5,463 Matching Annotations
  1. Aug 2023
    1. Reviewer #3 (Public Review):

      Liang and colleagues set out to test whether the human brain uses distance and grid-like codes in social knowledge using a design where participants had to navigate in a two-dimensional social space based on competence and warmth during an fMRI scan. They showed that participants were able to navigate the social space and found distance-based codes as well as grid-like codes in various brain regions, and the grid-like code correlated with behavior (reaction times).

      On the whole, the experiment is designed appropriately for testing for distant-based and grid-like codes and is relatively well-powered for this type of study, with a large amount of behavioral training per participant. They revealed that a number of brain regions correlated positively or negatively with distance in the social space, and found grid-like codes in the frontal polar cortex and posterior medial entorhinal cortex, the latter in line with prior findings on grid-like activity in the entorhinal cortex. The current paper seems quite similar conceptually and in design to previous work, most notably by Park et al., 2021, Nature Neuroscience.

      Below, I raise a few issues and questions on the evidence presented here for a grid-like code as the basis of navigating abstract social space or social knowledge.

      1. The authors claim that this study provides evidence that humans use a spatial / grid code for abstract knowledge like social knowledge.

      This data does specifically not add anything new to this argument. As with almost all studies that test for a grid code in a similar "conceptual" space (not only the current study), the problem is that when the space is not a uniform, square/circular space, and 2-dimensional then there is no reason the code will be perfectly grid-like, i.e., show six-fold symmetry. In real-world scenarios of social space (as well as navigation, semantic concepts), it must be higher dimensional - or at least more than two-dimensional. It is unclear if this generalizes to larger spaces where not all part of the space is relevant. Modelling work from Tim Behrens' lab (e.g., Whittington et al., 2020) and Bradley Love's lab (e.g., Mok & Love, 2019) have shown/argued this to be the case. In experimental work, like in mazes from the Mosers' labs (e.g., Derdikman et al., 2009), or trapezoid environments from the O'Keefe lab (Krupic et al., 2015), there are distortions in mEC cells, and would not pass as grid cells in terms of the six-fold symmetry criterion.

      The authors briefly discuss the limitations of this at the very end but do not really say how this speaks to the goal of their study and the claim that social space or knowledge is organized as a grid code and if it is in fact used in the brain in their study and beyond. This issue deserves to be discussed in more depth, possibly referring to prior work that addressed this, and raising the issue for future work to address the problem - or if the authors think it is a problem at all.

      Data and analysis

      2. Concerning the negative correlation of distance with activation in the fusiform gyrus and visual cortex: this is a slightly puzzling but potentially interesting finding. However, could this be related to reaction times? The larger the distance, the longer the reaction times, so the original finding might reflect larger activations with smaller distances.

      3. Concerning the correlation of grid-like activity with behavior: is the correlation with reaction time just about how long people took (rather than a task-related neural signal)? The authors have only reported correlations with reaction time. The issue here is that the duration of reaction times also relates to the starting positions of each trial and where participants will navigate to. Considering the speed-accuracy tradeoff, could performance accuracy be negatively correlated with these grid consistency metrics? Or it could be positively correlated, which would suggest the grid signal reflects a good representation of the task.

    1. Reviewer #3 (Public Review):

      Summary:

      In this manuscript, the authors report the first evidence of Nav1.5 regulation by a long noncoding RNA, LncRNA-DACH1, and suggest its implication in the reduction in sodium current observed in heart failure. Since no direct interaction is observed between Nav1.5 and the LncRNA, they propose that the regulation is via dystrophin and targeting of Nav1.5 to the plasma membrane.

      Strengths:

      1. First evidence of Nav1.5 regulation by a long noncoding RNA.<br /> 2. Implication of LncRNA-DACH1 in heart failure and mechanisms of arrhythmias.<br /> 3. Demonstration of LncRNA-DACH1 binding to dystrophin.<br /> 4. Potential rescuing of dystrophin and Nav1.5 strategy.

      Weaknesses:

      1. Main concern is that the authors do not provide evidence of how LncRNA-DACH1 regulates Nav1.5 protein level. The decrease in total Nav1.5 protein by about 50% seems to be the main consequence of the LncRNA on Nav1.5, but no mechanistic information is provided as to how this occurs.<br /> 2. The fact that the total Nav1.5 protein is reduced by 50% which is similar to the reduction in the membrane reduction questions the main conclusion of the authors implicating dystrophin in the reduced Nav1.5 targeting. The reduction in membrane Nav1.5 could simply be due to the reduction in total protein.

    1. Reviewer #3 (Public Review):

      Summary:

      The receptor tyrosine kinase Anaplastic Lymphoma Kinase (ALK) in humans is nervous system expressed and plays an important role as an oncogene. A number of groups have been signalling ALK signalling in flies to gain mechanistic insight into its various role. In flies, ALK plays a critical role in development, particularly embryonic development and axon targeting. In addition, ALK also was also shown to regulate adult functions including sleep and memory. In this manuscript, Sukumar et al., used a suite of molecular techniques to identify downstream targets of ALK signalling. They first used targeted DamID, a technique that involves a DNA methylase to RNA polymerase II, so that GATC sites in close proximity to PolII binding sites are marked. They performed these experiments in wild-type and ALK loss of function mutants (using an Alk dominant negative ALkDN), to identify Alk responsive loci. Comparing these loci with a larval single-cell RNAseq dataset identified neuroendocrine cells as an important site of Alk action. They further combined these TaDa hits with data from RNA seq in Alk Loss and Gain of Function manipulations to identify a single novel target of Alk signalling - a neuropeptide precursor they named Sparkly (Spar) for its expression pattern. They generated a mutant allele of Spar, raised an antibody against Spar, and characterised its expression pattern and mutant behavioural phenotypes including defects in sleep and circadian function.

      Strengths:

      The molecular biology experiments using TaDa and RNAseq were elegant and very convincing. The authors identified a novel gene they named Spar. They also generated a mutant allele of Spar (using CrisprCas technology) and raised an antibody against Spar. These experiments are lovely, and the reagents will be useful to the community. The paper is also well written, and the figures are very nicely laid out making the manuscript a pleasure to read.

      Weaknesses:

      My main concerns were around the genetics and behavioural characterisation which is incomplete. The authors generated a novel allele of Spar - Spar ΔExon1 and examined sleep and circadian phenotypes of this allele. However, they have only one mutant allele of Spar, and it doesn't appear as if this mutant was outcrossed, making it very difficult to rule out off-target effects. To make this data convincing, it would be better if the authors had a second allele, perhaps they could try RNAi?

      Further, the sleep and circadian characterisation could be substantially improved. In Fig 8 E-F it appears as if sleep was averaged over 30 days! This is a little bizarre. They then bin the data as day 1 - 12 and 12-30. This is not terribly helpful either. Sleep in flies, as in humans, undergoes ontogenetic changes - sleep is high in young flies, stabilises between day 3-12, and shows defects by around 3 weeks of age (cf Shaw et al., 2000 PMID 10710313). The standard in the sleep field is to average over 3 days or show one representative day. The authors should reanalyse their data as per this standard, and perhaps show data from 3-10 day old flies, and if they like from 20-30 day old flies. Further, sleep data is usually analysed and presented from lights on to lights on. This allows one to quantify important metrics of sleep consolidation including bout lengths in day and night, and sleep latency. These metrics are of great interest to the community and should be included.

      The authors also claim there are defects in circadian anticipatory activity. However, these data, as presented are not solid to me. The standard in the field is to perform eduction analyses and quantify anticipatory activity e.g. using the method of Harrisingh et al. (PMID: 18003827). Further, circadian period could also be evaluated. There are several free software packages to perform these analyses so it should not be hard to do.

    1. Reviewer #3 (Public Review):

      A central step in cell division is the formation of midbody abscission that separates two daughter cells at the end of cytokinesis. The ESCRT, endosomal sorting complexes required for transport, plays a critical role in this process. Specifically, the ESCRT-III proteins are actively recruited throughout the cell at the membrane fission sites, and their oligomerization into filaments is necessary to constrict the cell membranes to the fission point. Fundamental structural elements in ESCRT-III interactome are the so-called MIT-interacting motifs (MIMs) located at the protein's C terminal portion. Recently, Sundquist and co-workers (eLife 2022) identified several cofactors interacting with ESCRT-III subunits directly implicated in abscission. Among those cofactors, they identified Calpain-7, a cysteine protease whose function is still unclear. Calpain-7 comprises two MIT domains that target ESCRT-II subunit IST1. Here, the authors use structural methods and cell assays to characterize the interactions between Calpain-7 and IST1. For the structural studies, they constructed a minimalistic system in which MT1 and MT2 domains of Calpain-7 interact with the two MIMs localized in the IST1 construct. The truncated constructs interact with high affinity, recapitulating the strength of interaction expected for the full-length constructs in the cell. Using fluorescence polarization anisotropy binding isotherms, these researchers obtained solid binding data, showing a dissociation constant of 0.09 uM for the construct containing both MIMs, ~2 uM for the second MIM domain, and 100 uM for the first MIM. These data suggest a synergistic binding mechanism between the two MIM domains. The authors expressed and purified these constructs in recombinant systems and obtained purified isotopically labeled proteins to study by NMR. To characterize the binding by NMR, the authors studied the IST1 constructs with the two MIMs in the absence and presence of Calpain-7. The IST1 construct displays a well-resolved NMR fingerprint, with most resonances assigned to specific residues. Upon addition of the Calpain-7 construct, the resonances of the residues involved in the binding either broaden beyond detection or shift significantly, which supports the fluorescence binding studies. Given the high affinity, these authors were able to crystallize these complexes and identify the binding interfaces that parallel the solution NMR studies. Mutational studies confirm the hot spots for the interactions, and the authors concluded that the MIT:MIM binding interface is responsible for the association of the full-length constructs of Calpain-7 and IST1 in the cell. Using localization experiments, the authors concluded that IST1 is responsible for recruiting Calpain-7 to midbodies, and the presence of both MIT domains of Calpain-7 and MIM domains is required for localization. Taken together, the biophysical characterization of these complexes and the cell assays led the authors to conclude that IST1 binding to Calpain-7 is necessary for its role in abscission and Nocut checkpoint maintenance.<br /> In my opinion, the research is well executed and also supported by their previous finding (see Sundquist 2022 eLife). The paper is succinct and well-written.

    1. Reviewer #3 (Public Review):

      The manuscript by Salloum et al., titled "Statin-mediated reduction in mitochondrial cholesterol primes an anti-inflammatory response in macrophages by upregulating JMJD3" reports an extensive characterization of the mechanisms underlying the anti-inflammatory role of statins using different in vitro studies. Based on these approaches, the authors observed that cholesterol reduction in response to statin treatment alters mitochondrial function and they identify JMJD3 as a potential critical driver of macrophage anti-inflammatory phenotype. Overall, the study is interesting and provides new findings that could shed light on the molecular effects of statins in these cells, but a number of issues remain confusing, and the experimental design is, on some occasions, not rigorous enough to support the drawn conclusions.

      Major issues:

      1. Focus on JMJD3 is justified by the authors as it was among the 40 genes commonly up-regulated in macrophages exposed to statin or methyl--cyclodextrin (MCD) by RNA-Seq analysis. However, this analysis has not been presented in the manuscript and it is unclear what genes (apart from JMJD3) might play an important role in the response of these cells. A detailed characterization of both up- and down-regulated genes in these experimental conditions and a better justification for JMJD3 are required to fully support further analysis.<br /> 2. In the same line, Figures 6A and B fail to fully describe the changes found by ATAC-seq and RNA-seq. A more comprehensive analysis of these three datasets (together with previous RNA-seq studies) would help to obtain a better understanding of overlapping dysregulated genes (not only those found up-regulated) and what other epigenetic modifying factors might be involved.<br /> 3. In Figure 6C and Supplementary Figure 7, it would be noteworthy to also measure the gene expression of Kdm6a/UTX homolog Kdm6c/UTY, as it has been shown to lack demethylate H3K27me3 demethylase activity due to mutations in the catalytic site of the Jumomji-C-domain.<br /> 4. The use of rather unspecific treatments such as MG-132 (proteasome inhibitor) and GSKj4 (inhibitor of both JMJD3 and UTX) may distort the results observed and might elude their correct interpretation. To avoid this limitation, additional silencing and/or overexpression experiments are currently needed.<br /> 5. Figure 3 and Supplementary Figure 3 seem to be duplicated, please correct them. Moreover, for a better representation of these data, please include representative Seahorse profile figures of each experimental condition in these figures.<br /> 6. As stated by the authors, macrophage phenotype is much more complex than M1/M2 polarization. In this view, assessing a very limited set of genes (i.e, Il-1, IL-10, TNF, IL-6, IL-12, Arg1, Ym1, Mrc1) appears to be inappropriate. A meaningful number of markers must be added.<br /> 7. For accurate quantification of H3K27me3 global levels, please add immunoblotting against histone H3 in Supplementary Figure 1.

    1. Reviewer #3 (Public Review):

      The autocatalytic replication mechanism of misfolded Prion-like proteins (PrP) into amyloid aggregates is associated with a plethora of deleterious neurodegenerative diseases. Despite of the huge amount of research, the underlying molecular events of self-replication and identification of the toxic species are not fully understood. Many recent studies have indicated that non-fibrillar oligomeric intermediates could be more neurotoxic compared to the Prion fibrils. Various cellular factors, like the participation of other proteins and chaperone activity, also play an important role in PrP misfolding, aggregation, and neurotoxicity. The present work focuses on understanding the PrP aggregation mechanism with the identification of the associated toxic species and cellular factors. One of the significant strengths of the work is performing the aggregation assay in near-native conditions. In contrast, most in vitro studies use harsh conditions (such as high temperature, denaturant, detergent, low pH, etc.) to promote protein aggregation. The authors successfully observed the well-known seeding property of the PrP in this aggregation assay that bypasses the primary nucleation during aggregation. Moreover, the authors have shown that syntaxin 6 (Stx6), a known risk factor in prion-mediated Creutzfeldt-Jakob disease, delays fibril formation and prolongs the persistence of toxic intermediates, thus playing an anti-chaperone activity. This study will contribute to understanding the molecular mechanism of PrP aggregation and neurotoxicity. However, further studies are required to identify and characterize the toxic intermediate in the near future precisely.

    1. Reviewer #3 (Public Review):

      In this manuscript by Lu et al., the authors cloned TPC1 from Vicia faba (VfTPC1) and characterized its channel properties by patching the vacuoles isolated from VfRPC1 expressing TPC1-loss-of-function Arabidopsis mutant tpc1-2. They found that VfTPC1 displayed faster kinetics, higher voltage dependence, and less sensitivity to luminal calcium than its Arabidopsis orthologue (AtTPC1). Mutating three luminal residues (E457, E605 and D606) in AtTPC1 to the corresponding ones in VfTPC1 converted the channel into one that resembles VfTPC1: hyperactive and desensitized to luminal Ca2+. By constructing a VfTPC1 model based on the published Ca2+-bound AtTPC1-D454N (fou2) cryo-EM structures, the authors proposed a Ca2+-dependent interaction between the E605/D606 motif and a Ca2+ coordination site at the luminal entrance of the selectivity filter (D269/E637; in VfTPC1, D271/E639). Finally, they showed that vacuoles with VfTPC1 or AtTPC1- triple mutant were hyperexcitable. Overall, this is an interesting study that might have both evolutional and functional implications.

    1. Writing on small cards forces certain habits which would be good even for larger paper, but which I didn’t consider until the small cards made them necessary. It forces ideas to be broken up into simple pieces, which helps to clarify them. Breaking up ideas forces you to link them together explicitly, rather than relying on the linear structure of a notebook to link together chains of thought.

      A statement of the common "one idea per card" (or per note). He doesn't state it, but links to an article whose title is "One Thought Per Note".

      Who else has use this or similar phrasing in the historical record? - Beatrice Webb certainly came pretty close. - Others?

    2. one early reader of this write-up decided to use half 3x5 cards, so that they’d fit in mtg deck boxes.

      First reference I've seen for someone suggesting using half size 3 x 5" index cards so that they could use commercially available Magic: The Gathering (MTG) boxes.

      Oxford and possibly other manufacturers already make 1/2 size 3 x 5" index cards.

    1. Reviewer #3 (Public Review):

      The authors investigate the role of commensal microbes and molecules in the antigen presentation pathway in the development and phenotype of CD8 T cells specific for the Qa-1b-restricted peptide FL9 (QFL). The studies track both endogenous QFL-specific T cells and utilize a recently generated TCR transgenic model. The authors confirm that QFL-specific T cells in the spleen and small intestine intraepithelial lymphocyte (IEL) pool show an antigen-experienced phenotype as well as unique phenotypic and innate-like functional traits, especially among CD8+ T cells expressing Va3.2+ TCRs. They find that deficiency in the TAP transporter leads to almost complete loss of QFL-specific T cells but that loss of either Qa1 or the ERAAP aminopeptidase does not impact QFL+ T cell numbers but does cause them to maintain a more conventional, naïve-like phenotype. In germ-free (GF) mice, the QFL-specific T cells are present at similar numbers and with a similar phenotype to SPF animals, but in older animals (>18w) there is a notable loss of IEL QFL-specific cells. This drop can be avoided by neonatal colonization of GF mice with the commensal microbe Pediococcus pentosaceus but not a different commensal, Lactobacillus johnsonii, and the authors show that P. pentosaceus encodes a peptide that weakly stimulates QFL-specific T cells, while the homologous peptide from L. johnsonii does not stimulate such cells.

      This study provides new insights into the way in which the differentiation, phenotype, and function of CD8+ T cells specific for Qa-1b/FL9 is regulated by peptide processing and Qa1 expression, and by interactions with the microbiota. The approaches are well designed, the data compelling, and the interpretation, for the most part, appropriate. There are a few relatively minor concerns.

      1) For most of the report, the authors use a set of phenotypic traits to highlight the unique features of QFL-specific CD8+ T cells - specifically, CD44high, CD8aa+ve, CD8ab-ve. In Supp. Fig. 4, however, completely distinct phenotypic characteristics are presented, indicating that IEL QFL-specific T cells are CD5low, Thy-1low. No explanation is provided in the text about whether this is a previously reported phenotype, whether any elements of this phenotype are shared with splenic QFL T cells, what significance the authors ascribe to this phenotype (and to the fact that Qa1-deficiency leads to a more conventional Thy-1+ve, CD5+ve phenotype), and whether this altered phenotype is also seen in ERAAP-deficient mice. At least some explanation for this abrupt shift in focus and integration with prior published work is needed. On a related note, CD5 expression is measured in splenic QFL-specific CD8+ T cells from GF vs SPF mice (Supp. Fig. 9), to indicate that there is no phenotypic impact in the GF mice - but from Supp. Fig. 4, it would seem more appropriate to report CD5 expression in QFL-specific cells from the IEL, not the spleen.

      2) The authors suggest the finding that QFL-specific cells from ERAAP-deficient mice have a more "conventional" phenotype indicates some form of negative selection of high-affinity clones (this result being somewhat unexpected since ERAAP loss was previously shown to increase the presentation of Qa-1b loaded with FL9, confirmed in this report). It is not clear how this argument aligns with the data presented, however, since the authors convincingly show no significant reduction in the number of QFL-specific cells in ERAAP-knockout mice (Fig. 3a), and their own data (e.g. Fig. 2a) do not suggest that CD44 expression correlates with QFL-multimer staining (as a surrogate for TCR affinity/avidity). Is there some experimental basis for suggesting that ERAAP-deficient lacks a subset of high-affinity QFL-specific cells?

      3) The rationale for designing FL9 mutants, and for using these data to screen the proteomes of various commensal bacteria needs further explanation. The authors propose P4 and P6 of FL9 are likely to be "critical" but do not explain whether they predict these to be TCR or Qa-1b contact sites. Published data (e.g., PMID: 10974028) suggest that multiple residues contribute to Qa-1b binding, so while the authors find that P4A completely lost the ability to stimulate a QFL-specific hybridoma, it is unclear whether this is due to the loss of a TCR- or a Qa-1-contact site (or, possibly, both). This could easily be tested - e.g., by determining whether P4A can act as a competitive inhibitor for FL9-induced stimulation of BEko8Z (and, ideally, other Qa-1b-restricted cells, specific for distinct peptides). Without such information, it is unclear exactly what is being selected in the authors' screening strategy of commensal bacterial proteomes. This, of course, does not lessen the importance of finding the peptide from P. pentosaceus that can (albeit weakly) stimulate QFL-specific cells, and the finding that association with this microbe can sustain IEL QFL cells.

    1. Reviewer #3 (Public Review):

      In this study, Ruan et al. investigate the role of the IQCH gene in spermatogenesis, focusing on its interaction with calmodulin and its regulation of RNA-binding proteins. The authors examined sperm from a male infertility patient with an inherited IQCH mutation as well as IQCH CRISPR knockout mice. The authors found that both human and mouse sperm exhibited structural and morphogenetic defects in multiple structures, leading to reduced fertility in ICHQ-knockout male mice. Molecular analyses such as mass spectrometry and immunoprecipitation indicated that RNA-binding proteins are likely targets of IQCH, with the authors focusing on the RNA-binding protein HNRPAB as a critical regulator of testicular mRNAs. The authors used in vitro cell culture models to demonstrate an interaction between IQCH and calmodulin, in addition to showing that this interaction via the IQ motif of IQCH is required for IQCH's function in promoting HNRPAB expression. In sum, the authors concluded that IQCH promotes male fertility by binding to calmodulin and controlling HNRPAB expression to regulate the expression of essential mRNAs for spermatogenesis. These findings provide new insight into molecular mechanisms underlying spermatogenesis and how important factors for sperm morphogenesis and function are regulated.

      The strengths of the study include the use of mouse and human samples, which demonstrate a likely relevance of the mouse model to humans; the use of multiple biochemical techniques to address the molecular mechanisms involved; the development of a new CRISPR mouse model; ample controls; and clearly displayed results. There are some minor weaknesses in that more background details could be provided to the reader regarding the proteins involved; some assays could benefit from more rigorous quantification; some of the mouse testis images and analyses could be improved; and larger sample sizes, especially for the male mouse breeding tests, could be increased. Overall, the claims made by the authors in this manuscript are well-supported by the data provided and there are only minor technical issues that could increase the robustness and rigor of the study.

      1. More background details are needed regarding the proteins involved, in particular IQ proteins and calmodulin. The authors state that IQ proteins are not well-represented in the literature, but do not state how many IQ proteins are encoded in the genome. They also do not provide specifics regarding which calmodulins are involved, since there are at least 5 family members in mice and humans. This information could help provide more granular details about the mechanism to the reader and help place the findings in context.

      2. The mouse fertility tests could be improved with more depth and rigor. There was no data regarding copulatory plug rate; data was unclear regarding how many WT females were used for the male breeding tests and how many litters were generated; the general methodology used for the breeding tests in the Methods section was not very explicitly or clearly described; the sample size of n=3 for the male breeding tests is rather small for that type of assay; and, given that ICHQ appears to be expressed in testicular interstitial cells (Fig. S10) and somewhat in other organs (Fig. S2), another important parameter of male fertility that should be addressed is reproductive hormone levels (e.g., LH, FSH, and testosterone).

      3. The Western blots in Figure 6 should be rigorously quantified from multiple independent experiments so that there is stronger evidence supporting claims based on those assays.

      4. Some of the mouse testis images could be improved. For example, the PNA and PLCz images in Figure S7 are difficult to interpret in that the tubules do not appear to be stage-matched, and since the authors claimed that testicular histology is unaffected in knockout testes, it should be feasible to stage-match control and knockout samples. Also, the anti-ICHQ and CaM immunofluorescence in Figure S10 would benefit from some cell-type-specific co-stains to more rigorously define their expression patterns, and they should also be stage-matched.

    1. Reviewer #3 (Public Review):

      Summary. This study sought to clarify the connection between inositol pyrophosphates (IPPs) and their regulation of phosphate homeostasis in the yeast Saccharomyces cerevisiae to answer the question of whether any of the IPPs (1-IP7, 5-IP7, and IP8) or only particular IPPs are involved in regulation. IPPs bind to SPX domains in proteins to affect their activity, and there are several key proteins in the PHO pathway that have an SPX domain, including Pho81. The authors use the latest methodology, capillary electrophoresis and mass spectrometry (CE-MS), to examine the cytosolic concentrations of PP-IPs in wild-type and strains carrying mutations in the enzymes that metabolize these compounds in rich medium and during a phosphate starvation time-course for the wild-type.

      Major strengths and weaknesses. The authors have strong premises for performing these experiments: clarifying the regulatory molecule(s) in yeast and providing a unifying mechanism across eukaryotes. They use the latest methodologies and a variety of approaches including genetics, biochemistry, cell biology and protein structure to examine phosphate regulation. Their experiments are rigorous and well controlled, and the story is clearly told. The consideration of physiological levels of IPPs throughout the study was critical to interpretation of the data and a strength of the manuscript. The investigation of the structure of Pho81, its regulation by IPPs, and its interactions with Pho80 provide a vivid model for regulation.

      Appraisal. The authors achieved their goal of determining the mechanistic details for phosphate regulation, revising the prior model with new insights. Additionally, they provided strong support for the idea that IP8 regulates phosphate metabolism across eukaryotes - including animals and plants in addition to fungi.

      Impact. This study is likely to have broad impact because it addresses prior findings that are inconsistent with current understanding, and they provide good reasoning as to how older methods were inadequate.

    1. Reviewer #3 (Public Review):

      This study investigated cognitive mechanisms underlying approach-avoidance behavior using a novel reinforcement learning task and computational modelling. Participants could select a risky "conflict" option (latent, fluctuating probabilities of monetary reward and/or unpleasant sound [punishment]) or a safe option (separate, generally lower probability of reward). Overall, participant choices were skewed towards more rewarded options, but were also repelled by increasing probability of punishment. Individual patterns of behavior were well-captured by a reinforcement learning model that included parameters for reward and punishment sensitivity, and learning rates for reward and punishment. This is a nice replication of existing findings suggesting reward and punishment have opposing effects on behavior through dissociated sensitivity to reward versus punishment.

      Interestingly, avoidance of the conflict option was predicted by self-reported task-induced anxiety. Importantly, when a subset of participants were retested over 1 week later, most behavioral tendencies and model parameters were recapitulated, suggesting the task may capture stable traits relevant to approach-avoidance decision-making.

      The revised paper commendably adds important additional information and analyses to support these claims. The initial concern that not accounting for participant control over punisher intensity confounded interpretation of effects has been largely addressed in follow-up analyses and discussion.

      This study complements and sits within a broad translational literature investigating interactions between reward/punishers and psychological processes in approach-avoidance decisions.

    1. Reviewer #3 (Public Review):

      The authors of this study have designed a novel screening pipeline to detect DNA motif spacing preferences between TF partners using publicly available data. They were able to recapitulate previously known composite elements, such as the AP-1/IRF4 composite elements (AICE) and predict many composite elements that are expected to be very useful to the community of researchers interested in dissecting the regulatory logic of mammalian enhancers and promoters. The authors then focus on a novel, SPICE predicted interaction between JUN and IKZF1, and show that under LPS and IL-21 treatment, JUN and IKZF1 in B cells have significant overlap in their genomic localization. Next, to know whether the two TFs physically interact, a co-immunoprecipitation experiment was performed. While JUN immunoprecipitated with an anti-IKZF1 antibody, curiously IKZF1 did not immunoprecipitate with an anti-JUN antibody. Finally, EMSA and luciferase experiments were performed to show that the two TFs bind cooperatively at an IL20 upstream probe.

      Major strengths:<br /> 1. SPICE was able to recapitulate previously known composite elements, such as the AP-1/IRF4 composite elements (AICE).<br /> 2. Under LPS and IL-21 treatment, JUN and IKZF1 in B cells have significant overlap in their genomic localization. This is very good supporting evidence for the efficacy of SPICE in detecting TF partners.

      Major weaknesses:<br /> 1. The authors fail to convincingly show that IKZF1 and Jun physically interact. A quantitative measurement of their interaction strength would have been ideal.<br /> 2. The super-shift experiment to show that the proteins bound to their EMSA probe were indeed IKZF1 and JUN are not very convincing and would benefit from efforts to quantify the shift (Figure 3E). Nuclear extracts from cells with single or double CRISPR knock outs of the two TFs would have been ideal.<br /> 3. There is a second band beneath the more prominent band in the EMSA experiment with recombinant IKZF1 and JUN (Figure 4C). This second band is most probably bound by IKZF1 because it becomes weaker when the IKZF1 site is mutated and is completely absent when only JUN is added. This is completely ignored by the authors. Therefore, experiments with EMSA fail to convincingly show that IKZF1 and Jun bind cooperatively. They could just as well bind independently to the two sites.

    1. Reviewer #3 (Public Review):

      Laham et al. present a manuscript investigating the function of adult-born granule cells (abGCs) projecting to the CA2 region of the hippocampus during social memory. It should be noted that no function for the general DG to CA2 projection has been proposed yet. The authors use targeted ablation, chemogenetic silencing, and in vivo ephys to demonstrate that the abGCs to CA2 projection is necessary for the retrieval of remote social memories such as the memory of one's mother. They also use in vivo ephys to show that abGCs are necessary for differential CA2 network activity, including theta-gamma coupling and sharp wave-ripples, in response to novel versus familiar social stimuli.

      The question investigated is important since the function of DG to CA2 projection remained elusive a decade after its discovery. Overall, the results are interesting but focused on the social memory of the mother, and their description in the manuscript and figures is too cursory. For example, raw interaction times must be shown before their difference. The assumption that mice exhibit social preference between familiar or novel individuals such as mother and non-mother based on social memory formation, consolidation, and retrieval should be better explained throughout the manuscript. Thus, when describing the results, the authors should comment on changes in preference and how this can be interpreted as a change in social memory retrieval. Several critical experimental details such as the total time of presentation to the mother and non-mother stimulus mice are also lacking in the manuscript. The in vivo e-phys results are interesting as well but even more succinct with no proposed mechanism as to how abGCs could regulate SWR and PAC in CA2.

      The manuscript is well-written with the appropriate references. The choice of the behavioral test is somewhat debatable, however. It is surprising that the authors chose to use a direct presentation test (presentation of the mother and non-mother in alternation) instead of the classical 3-chamber test which is particularly appropriate to investigate social preference. Since the authors focused exclusively on this preference, the 3-chamber test would have been more adequate in my opinion. It would greatly strengthen the results if the authors could repeat a key experiment from their investigation using such a test. In addition, the authors only impaired the mother's memory. An additional experiment showing that disruption of the abGCs to CA2 circuit impairs social memory retrieval would allow us to generalize the findings to social memories in general. As the manuscript stands, the authors can only conclude the importance of this circuit for the memory of the mother. Developmental memory implies the memory of familiar kin as well.

      The in vivo ephys section (Figure 3) is interesting but even more minimalistic and it is unclear how abGCs projection to CA2 can contribute to SWR and theta-gamma PAC. In Figure 1, the authors suggest that abGCs project preferentially to PV+ neurons in CA2. At a minimum, the authors should discuss how the abGCs to PV+ neurons to CA2 pyramidal neurons circuit can facilitate SWR and theta-gamma PAC.

      Finally, proposing a function for 4-6-week-old abGCs projecting to CA2 begs two questions: What are abGCs doing once they mature further, and more generally, what is the function of the DG to CA2 projection? It would be interesting for the authors to comment on these questions in the discussion.

    1. Reviewer #3 (Public Review):

      The potential for sexual selection and the extent of sexual dimorphism in gene expression have been studied in great detail in animals, but hardly examined in plants so far. In this context, the study by Zhao, Zhou et al. al represents a welcome addition to the literature.

      Relative to the previous studies in Angiosperms, the dataset is interesting in that it focuses on reproductive rather than somatic tissues (which makes sense to investigate sexual selection), and includes more than a single developmental stage (buds + mature flowers).

      The main limitation of the study is the very low number of samples analyzed, with only three replicate individuals per sex (i.e. the whole study is built on six individuals only). This provides low power to detect differential expression. Along the same line, only three species were used to evaluate the rates of non-synonymous to synonymous substitutions, which also represents a very limited dataset, in particular when trying to fit parameter-rich models such as those implemented here.

      A third limitation relates to the absence of a reference genome for the species, making the use of a de novo transcriptome assembly necessary, which is likely to lead to a large number of incorrectly assembled transcripts. Of course, the production of a reference transcriptome in this non-model species is already a useful resource, but this point should at least be acknowledged somewhere in the manuscript.

      Each of these shortcomings is relatively important, and together they strongly limit the scope of the conclusions that can be made, and they should at least be acknowledged more prominently. The study is valuable in spite of these limitations and the topic remains grossly understudied, so I think the study will be of interest to researchers in the field, and hopefully inspire further, more comprehensive analyses.

    1. Reviewer #3 (Public Review):

      More than 80 million people live at high altitude. This impacts health outcomes, including those related to pregnancy. Longer-lived populations at high altitudes, such as the Tibetan and Andean populations show partial protection against the negative health effects of high altitude. The paper by Yue sought to determine the mechanisms by which the placenta of Tibetans may have adapted to minimise the negative effect of high altitude on fetal growth outcomes. It compared placentas from pregnancies from Tibetans to those from the Han Chinese. It employed RNAseq profiling of different regions of the placenta and fetal membranes, with some follow-up of histological changes in umbilical cord structure and placental structure. The study also explored the contribution of fetal sex in these phenotypic outcomes.

      A key strength of the study is the large sample sizes for the RNAseq analysis, the analysis of different parts of the placenta and fetal membranes, and the assessment of fetal sex differences.

      A main weakness is that this study, and its conclusions, largely rely on transcriptomic changes informed by RNAseq. Changes in genes and pathways identified through bioinformatic analysis were not verified by alternate methods, such as by western blotting, which would add weight to the strength of the data and its interpretations. There is also a lack of description of patient characteristics, so the reader is unable to make their own judgments on how placental changes may link to pregnancy outcomes. Another weakness is that the histological analyses were performed on n=5 per group and were rudimentary in nature.

    1. Reviewer #3 (Public Review):

      The manuscript by Egan and coworkers investigates how Caspase-1 and Caspase-4 mediated cell death affects replication of Salmonella in human THP-1 macrophages in vitro.

      Overall evaluation:

      Strength of the study include the use of human cells, which exhibit notable differences (e.g., Caspase 11 vs Caspase-4/5) compared to commonly used murine models. Furthermore, the study combines inhibitors with host and bacterial genetics to elucidate mechanistic links.

      The main weaknesses of the study are the inherent limitations of tissue culture models. For example, to study interaction of Salmonella with host cells in vitro, it is necessary to kill extracellular bacteria using gentamicin. However, since Salmonella-induced macrophage cell death damages the cytosolic membrane, gentamicin can reach intracellular bacteria and contribute to changes in CFU observed in tissue culture models (major point 1). This can result in tissue culture "artefacts" (i.e., observations/conclusions that cannot be recapitulated in vivo). For example, intracellular replication of Salmonella in murine macrophages requires T3SS-2 in vitro, but T3SS-2 is dispensable for replication in macrophages of the spleen in vivo (Grant et al., 2012).

      Major comments:

      In Figure 1: are increased CFU in WT vs CASP1-deficient THP-1 cells due to Caspase 1 restricting intracellular replication or due to Caspase-1 causing pore formation to allow gentamicin to enter the cytosol thereby restricting bacterial replication? The same question arises about Caspase-4 in Figure 2, where differences in CFU are observed only at 24h when differences in cell death also become apparent. The idea that gentamicin entering the cytosol through pores is responsible for controlling intracellular Salmonella replication is also consistent with the finding that GSDMD-mediated pore formation is required for restricting intracellular Salmonella replication (Figure 3). Similarly, the finding that inflammasome responses primarily control Salmonella replication in the cytosol could be explained by an intact SCV membrane protecting Salmonella from gentamicin (Figure 5).

    1. Reviewer #3 (Public Review):

      Strengths:

      NanoPDLIM2, nanotechnologies that efficiently deliver lentivirus overcomes resistance to chemotherapy and anti-PD-1 immunotherapy. This is a new strategy for enhancing the efficiency of immune checkpoint inhibitors. This finding is important from a clinical translation perspective, but I have several minor concerns.

      Weaknesses:

      1. Please describe the mechanism of increased MHC class I and PD-L1 by PDLIM2.<br /> 2. Please describe the mechanism of decreased MDR1, nuclear RelA and STAT3 by PDLIM2.<br /> 3. Please determine whether PDLIM2 expression directly impacts immune cells (function and number)?<br /> 4. What is the efficiency of PDLIM2 delivery? Does delivery efficiency determine anti-tumor effect?<br /> 5. Authors used a non-immunogenic tumor model. Can you demonstrate the combination effect with PDLIM2 in immunogenic lung cancer models to determine whether the combination of PDLIM2 with anti-PD-1 Ab confers a synergistic effect without chemotherapy?<br /> 6. On page 11, % change can make one over-interpret data.<br /> 7. In Figure 5, what is the difference between 5A and 5D?<br /> 8. It is unclear whether PDLIM2 confers an additive or a synergistic effect with anti-PD-1/chemo.<br /> 9. Have the authors tested any toxicity in normal lungs?

    1. Reviewer #3 (Public Review):

      I very much like this approach and the idea of incorporating hypervariable markers. The method is intriguing, and the ability to e.g. estimate recombination rates, the size of DMRs, etc. is a really nice plus. I am not able to comment on the details of the statistical inference, but from what I can evaluate it seems sound and reasonable. This is an exciting new avenue for thinking about inference from genomic data. I have a few concerns about the presentation and then also questions about the use of empirical methylation data sets.

      I think a more detailed description of demographic accuracy is warranted. For example, in L245 MSMC2 identifies the bottleneck (albeit smoothed) and only slightly overestimates recent size. In the same analysis the authors' approach with unknown mu infers a nonexistent population increase by an order of magnitude that is not mentioned.

      Similarly, it seems problematic that (L556) the approach requiring estimation of site and region parameters (as would presumably be needed in most empirical systems like endangered nonmodel species mentioned in the introduction) does no better than using only SNPs. Overall, I think a more objective and perhaps quantitative comparison of approaches is warranted.

      The authors simulate methylated markers at 2% (and in some places up to 20%). In many plant genomes a large proportion of cytosines are methylated (e.g. 70% in maize: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8496265/). I don't know what % of these may be polymorphic, but this leads to an order of magnitude more methylated cytosines than there are SNPs. Couldn't this mean that any appreciable error in estimating methylation threatens to be of a similar order of magnitude to the SNP data? I would welcome the authors' thoughts here.

      A few points of discussion about the biology of methylation might be worth including. For example, methylation can differ among cell types or cells within a tissue, yet sequencing approaches evaluate a pool of cells. This results in a reasonable fraction of sites having methylation rates not clearly 0 or 1. How does this variation affect the method? Similarly, while the authors cite literature about the stable inheritance of methylation, a sentence or so more about the time scale over which this occurs would be helpful. Finally, in some species methylated cytosines have mutation rates an order of magnitude higher than other nucleotides. The authors mention they assume independence, but how would violation of this assumption affect their inference?

    1. Reviewer #3 (Public Review):

      In this manuscript, Lewis et al. investigate the role of tetraspanins in the formation of discs - the key structure of vertebrate photoreceptors essential for light reception. Two tetraspanin proteins play a role in this process: PRPH2 and ROM1. The critical contribution of PRPH2 has been well established and loss of its function is not tolerated and results in gross anatomical pathology and degeneration in both mice and humans. However, the role of ROM1 is much less understood and has been considered somewhat redundant. This paper provides a definitive answer about the long-standing uncertainty regarding the contribution of ROM1 firmly establishing its role in outer segment morphogenesis. First, using an ingenious quantitative proteomic technique the authors show PRPH2 compensatory increase in ROM1 knockout explaining the redundancy of its function. Second, they uncover that despite this compensation, ROM1 is still needed, and its loss delays disc enclosure and results in the failure to form incisures. Third, the authors used a transgenic mouse model and show that deficits seen in ROM1 KO could be completely compensated by the overexpression of PRPH2. Finally, they analyzed yet another mouse model based on double manipulation with both ROM1 loss and expression of PRPH2 mutant unable to form dimerizing disulfide bonds further arguing that PRPH2-ROM1 interactions are not required for disc enclosure. To top it off the authors complement their in vivo studies by a series of biochemical assays done upon reconstitution of tetraspanins in transfected cultured cells as well as fractionations of native retinas. This report is timely, addresses significant questions in cell biology of photoreceptors, and pushes the field forward in a classical area of photoreceptor biology and mechanics of membrane structure as well. The manuscript is executed at the top level of technical standard, exceptionally well written, and does not leave much more to desire. It also pushes standards of the field- one such domain is the quantitative approach to analysis of the EM images which is notoriously open to alternative interpretations - yet this study does an exceptional job unbiasing this approach.

      According to my expertise in photoreceptor biology, there is nothing wrong with this manuscript either technically or conceptually and I have no concerns to express.

    1. Reviewer #3 (Public Review):

      Hon et al. investigated the role of BNST CRF signaling in modulating phasic and sustained fear in male and female mice. They found that partial and full fear conditioning had similar effects in both sexes during conditioning and during recall. However, males in the partially reinforced fear conditioning group showed enhanced acoustic startle, compared to the fully reinforced fear conditioning group, an effect not seen in females. Using fiber photometry to record calcium activity in all BNST neurons, the authors show that the BNST was responsive to foot shock in both sexes and both conditioning groups. Shock response increased over the session in males in the fully conditioned fear group, an effect not observed in the partially conditioned fear group. This effect was not observed in females. Additionally, tone onset resulted in increased BNST activity in both male groups, with the tone response increasing over time in the fully conditioned fear group. This effect was less pronounced in females, with partially conditioned females exhibiting a larger BNST response. During recall in males, BNST activity was suppressed below baseline during tone presentations and was significantly greater in the partially conditioned fear group. Both female groups showed an enhanced BNST response to the tone that slowly decayed over time. Next, they knocked CRF in the BNST to examine its effect on fear conditioning, recall and anxiety-like behavior after fear. They found no effect of the knockdown in either sex or group during fear conditioning. During fear recall, BNST CRF knockdown lead to an increase in freezing in only the partially conditioned females. In the anxiety-like behavior tasks, BNST CRF knockdown lead to increased anxiolysis in the partially reinforced fear male, but not in females. Surprisingly, BNST CRF knockdown increased startle response in fully conditioned, but not partially conditioned males. An effect not observed in either female group. In a final set of experiments, the authors single photon calcium imaging to record BNST CRF cell activity during fear conditioning and recall. Approximately, 1/3 of BNST CRF cells were excited by shock in both sexes, with the rest inhibited and no differences were observed between sexes or group during fear conditioning. During recall, BNST CRF activity decreased in both sexes, an effect pronounced in male and female fully conditioned fear groups.

      Overall, these data provide novel, intriguing evidence in how BNST CRF neurons may encode phasic and sustained fear differentially in males and females. The experiments were rigorous.

    1. Reviewer #3 (Public Review):

      Summary:<br /> The manuscript Kroon et al. described two algorithms, which when combined achieve high throughput automation of "martinizing" protein structures with selected protonation states and post-translational modifications.

      Strengths:<br /> A large scale protein simulation was attempted, showing strong evidence that authors' algorithms work smoothly.

      The authors described the algorithms in detail and shared the open-source code under Apache 2.0 license on GitHub. This allows both reproducibility of extended usefulness within the field. These algorithms are potentially impactful if the authors can address some of the issues listed below.

      Weaknesses:<br /> One major caveat of the manuscript is that the authors claim their algorithms aim to "process any type of molecule or polymer, be it linear, cyclic,<br /> branched, or dendrimeric, and mixtures thereof" and "enable researchers to prepare simulation input files for arbitrary (bio)polymers". However, the examples provided by the manuscript only support one type of biopolymer, i.e. proteins. Despite the authors' recommendation of using polyply along with martinize2/vermouth, no concrete evidence has been provided to support the authors' claim. Therefore, the manuscript must be modified to either remove these claims or include new evidence.

      Method descriptions on Martinize2 and graph algorithms in SI should be core content of the manuscript. I argue that Figure S1 and Figure S2 are more important than Figure 3 (protonation state). I recommend the authors can make a workflow chart combining Figure S1 and S2 to explain Martinize2 and graph algorithms in main text.

      In Figure 3 (protonation state), the figure itself and the captions are ambiguous about whether at the end the residue is simply renamed from HIS to HIP, or if hydrogen is removed from HIP to recover HIS.

      In "Incorporating a Ligand small-molecule Database", the authors are calling for a community effort to build a small-molecule database. Some guidance on when the current database/algorithm combination does or does not work will help the community in contributing.

      A speed comparison is needed to compare Martinize2 and Martinize.

    1. Reviewer #3 (Public Review):

      To analyze the circuit mechanisms leading to the habituation of the O-bed responses upon repeated dark flashes (DFs), the authors performed 2-photon Ca2+ imaging in larvae expressing nuclear-targeted GCaMP7f pan-neuronally panning the majority of the midbrain, hindbrain, pretectum, and thalamus. They found that while the majority of neurons across the brain depress their responsiveness during habituation, a smaller population of neurons in the dorsal regions of the brain, including the torus longitudinalis, cerebellum, and dorsal hindbrain, showed the opposite pattern, suggesting that motor-related brain regions contain non-depressed signals, and therefore likely contribute to habituation plasticity.

      Further analysis using affinity propagation clustering identified 12 clusters that differed both in their adaptation to repeated DFs, as well as the shape of their response to the DF.

      Next by the pharmacological screening of 1953 small molecule compounds with known targets in conjunction with the high-throughput assay, they found that 176 compounds significantly altered some aspects of measured behavior. Among them, they sought to identify the compounds that 1) have minimal effects on the naive response to DFs, but strong effects during the training and/or memory retention periods, 2) have minimal effects on other aspects of behaviors, 3) show similar behavioral effects to other compounds tested in the same molecular pathway, and identified the GABAA/C Receptor antagonists Bicuculline, Amoxapine, and Picrotoxinin (PTX). As partial antagonism of GABAAR and/or GABACR is sufficient to strongly suppress habituation but not generalized behavioral excitability, they concluded that GABA plays a very prominent role in habituation. They also identified multiple agonists of both Melatonin and Estrogen receptors, indicating that hormonal signalling may also play a prominent role in habituation response.

      To integrate the results of the Ca2+ imaging experiments with the pharmacological screening results, the authors compared the Ca2+ activity patterns after treatment with vehicle, PTX, or Melatonin in the tethered larvae. The behavioral effects of PTX and Melatonin were much smaller compared with the very strong behavioral effects in freely-swimming animals, but the authors assumed that the difference was significant enough to continue further experiments. Based on the hypothesis that Melatonin and GABA cooperate during habituation, they expected PTX and Melatonin to have opposite effects. This was not the case in their results: for example, the size of the 12(Pot, M) neuron population was increased by both PTX and Melatonin, suggesting that pharmacological manipulations that affect habituation behavior manifest in complex functional alterations in the circuit, making capturing these effects by a simple difficult.

      Since the 12(𝑃𝑜𝑡, 𝑀) neurons potentiate their responses and thus could act to progressively depress the responses of other neuronal classes, they examined the identity of these neurons with GABA neurons. However, GABAergic neurons in the habituating circuit are not characterized by their Adaptation Profile, suggesting that global manipulations of GABAergic signalling through PTX have complex manifestations in the functional properties of neurons.

      Overall, the authors have performed an admirably large amount of work both in whole-brain neural activity imaging and pharmacological screening.

    1. Reviewer #3 (Public Review):

      In this paper, Toschi et al. performed dMRI to in vivo estimate axon diameter in the brain and demonstrated that multi-compartmental modeling (AxCaliber) is sensitive to microstructural axonal damage in rats and axon caliber increase in demyelinating lesions in MS patients, suggesting that axon diameter mapping provides a potential biomarker to bridge the gap between medical imaging contrasts and biological microstructure. In particular, authors injected ibotenic acid (IBO) and saline in the left and right rat hippocampus, respectively, and compared in vivo estimated axon diameter and ex vivo neurofilament staining in left and right fimbria. The axon size estimation was larger in the fimbria of IBO injection side, where the neurofilament intensity is higher. Correlation of axon size estimation and neurofilament intensity was observed in both injection sides. Further, higher axon diameter estimation was observed in normal appearing white matter (NAWM) of MS patients, compared with the healthy subjects. The axon size estimation increased in hypointense lesions of T1 weighted contrast, but not in isointense lesions. Through the comparison of dMRI-estimated axon size and histology-based fluorescence intensity, authors indirectly validated the sensitivity of axon diameter mapping to the tissue microstructure in the rat brain, and further explored the axon size change in the brain of MS patients. However, the dMRI protocol and biophysical modeling in this study were not fully optimized to maximize the sensitivity to axon size estimation, and the dMRI-estimated axon size (4.4-5.4 micron) was much larger than values reported in previous histological studies (0.5-3 micron) [Barazany et al., Brain 2009]. Finally, although the modified AxCaliber model incorporated two fiber bundles in different directions, the fiber dispersion in each bundle was not considered (c.f. fiber dispersion ~20-30 degree in corpus callosum), potentially leading to overestimated axon diameter.

      The conclusions in this study are supported by experimental results. However, the dMRI protocol and biophysical model could be further optimized and validated:<br /> 1. To in vivo estimate the axon diameter ~1 micron using dMRI, strong diffusion weighting (b-value) should be applied to maximize the signal decay due to intra-axonal restricted diffusion and minimize the signal contribution of extra-cellular hindered diffusion. However, authors only applied maximal b-value = 4000 s/mm2, much smaller than values ~15,000-20,000 s/mm2 in previous studies [Assaf et al., MRM 2008; Huang et al., BSAF 2020, 225:1277]. The use of low diffusion weighting in this study leads to a lower bound ~4-6 micron for accurate diameter estimation, the so-called resolution limit in [Nilsson et al., NMR Biomed 2017, 30:e3711]. In other words, the estimated axon diameter is potentially overestimated and related with the imaging protocol and image quality, confounding the biological interpretation.<br /> 2. In this study, the positive correlation of dMRI-estimated axon size and neurofilament fluorescence intensity is indeed an encouraging result, and yet this validation is indirect since it relies on the positive correlation between neurofilament intensity and axon diameter in histology.<br /> 3. Authors did not consider the fiber dispersion in the proposed dMRI model. This can lead to overestimated axon diameter, even in the highly aligned WM, such as corpus callosum with ~20-30 degree dispersion in histology [Ronen et al., BSAF 2014, 219:1773; Leergaard et all, PLoS One 2010, 5(1), e8595] and MRI [Dhital et al., NeuroImage 2019, 189, 543; Novikov et al., NeuroImage 2018, 174:518].

    1. Reviewer #3 (Public Review):

      This study examined the changes in fear response, as measured by the flight initiation distances (FID), of birds living in urban areas. The authors examined the FIDs of birds during the pandemic (COVID-19 lockdown restrictions) compared to FIDs measured before the pandemic (mostly in 2018 & 2019). The main study justification was that human presence changed drastically during the pandemic lockdowns and the change in human presence might have influenced the fear response of birds as a result of changing the "landscape of fear". Human presence was quantified using a 'stringency' index (government-mandated restrictions). Urban areas were selected from within five different cities, which included four European cities (Czech Republic - Prague, Finland - Rovaniemi, Hungary - Budapest, Poland - Poznan), and one city in the global south (Australia - Melbourne). Using 6369 flight initiation distances across 147 different bird species, the authors found that FIDs were not significantly different before the pandemic versus during the pandemic, nor was the variation in FID explained by the level of 'stringency'.

      Major strengths: There are several strengths to this study that allows for understanding the variety of factors that influence a bird's response to fear (measured as flight initiation distances). This study also demonstrates that FIDs are highly variable between species and regions.<br /> Specifically,<br /> 1) One of the major strengths of this paper is the focus on birds living in urban areas, a habitat type that is hypothesized to have changed drastically in the 'landscape of fear' experienced by animals during the pandemic lockdown restrictions (due to the presumed decrease in human presence and densities). Maintaining the focus on urban birds allowed for a deeper examination of the effect of human behaviour changes on bird behaviour in urban habitats, which are at the interface of human-wildlife interactions.<br /> 2) This study accounted for several variables that are predicted to influence flight initiation distances in birds including species, genus, region (country), variability between years, pandemic year (pre- versus during), the strictness of government-mandated lockdown measures, and ecological factors such as the human observer starting distance, flock size, species-specific body size, ambient air temperature (also a proxy of the timing during the breeding season), time of day, date of data collection (timing within the regional [Europe or Australia] breeding season), and categorization of urban site type (e.g. park, cemetery, city centre).<br /> 3) This study examined FIDs in two years previous to the pandemic (mostly 2018 and 2019, one site was 2014) which would account for some of the within- and between-year FID variation exhibited prior to the pandemic.<br /> 4) This study uses strong statistical approaches (mixed effect models) which allows for repeat sampling, and a post hoc analysis testing for a phylogenetic signal.

      Major weaknesses: The authors used government 'stringency' as a proxy for human presence and densities, however, this may not have been an accurate measure of actual human presence at the study sites and during measurements of FIDs. Furthermore, although the authors accounted for many factors that are predicted to influence fear response and FIDs in birds, there are several other factors that may have contributed to the high level of variation and patterns in FIDS observed during this study, thus resulting in the authors' conclusion that FIDs did not vary between pre- and during pandemic years.<br /> Specifically,<br /> 1) The authors used "government stringency" as a measure of change in human activity, which makes the assumption that the higher the level of 'stringency', the fewer humans in urban areas where birds are living. However, the association between "stringency" and actual human presence at the study sites was not measured, nor was 'stringency' compared to other measures of human presence such as human mobility.<br /> 2) There was considerable variation in FID measurements, which can be seen in the figures, indicating that most of the variation in FID was not accounted for in the authors' models. Factors that may have contributed to variation in FIDs that were not accounted for in this study are as follows:<br /> a. The authors accounted for the date of data collection using the 'day' since the start of the general region's breeding season (Europe: Day 1 = 1 April; Australia: Day 1 = 15 August). Using 'day' since the breeding season started probably was an attempt to quantify the effect of the breeding stage (e.g. territory establishment, nest young, fledgling) on FIDs. However, breeding stages vary both within- and between species, as well as between sub-regions (e.g. Finland vs. Hungary). As different species respond to predation or human presence differently depending on the stage during their breeding cycle, more specificity in the breeding cycle stage may allow for explaining the observed variation and patterns in FID.<br /> b. Variation in species-specific FIDs may also vary with habitat features within urban sites, such as the proximity of trees and other protective structures (e.g. perches and cover), the openness of the area, and the level of stressors present (e.g. noise pollution, distance to roads). Perhaps accounting for this habitat heterogeneity would account for the FID variation measured in this study.<br /> c. The authors accounted for species and genus within their models, however, FIDs may vary with other species-specific (or even specific populations of a species) characteristics such as whether the species/population is neophobic versus neophilic, precocial versus altricial, and the level of behavioural plasticity exhibited. These variables were not accounted for in the analysis.<br /> d. Three different methods of measuring the distances between flight and the observer location were used, and FIDs were only measured once per bird, such that there were no measures of repeatability for a test subject. Thus, variation surrounding the measurement of FIDs would have contributed to the variation in FIDs seen during this study.<br /> 3) The sample design of this study may have influenced the FID variability associated with specific species, and specific populations of species. A different number of species were sampled across the time periods of interest; 68 species were sampled before the pandemic versus 135 species after the pandemic. However, the authors do not appear to have directly compared the FIDs for the same species before the pandemic compared to during the pandemic (e.g. the FIDs of Eurasian blackbirds before the pandemic versus during the pandemic). Furthermore, within the same country-city, it is unclear whether the species observed before the pandemic were observed at the same location (e.g. same habitat type such as the same park) during the pandemic. As a species' FID response may be influenced by population characteristics and features specific to each site (e.g. habitat openness), these factors may have influenced the variability in FID measurements in this study.<br /> 4) The models in this study accounted for many factors predicted to affect FIDs (see the section on major strengths), however, the number of fixed and random factors are large in number compared to the total sample size (N =6369), such that models may have been over-extended.

      Overarching main conclusion<br /> Overall, this study examines factors influencing FIDs in a variety of bird species and concludes that FIDs did not differ during the pandemic lockdowns compared to before the pandemic (2019 and earlier). Furthermore, FIDs were not influenced by the strictness of government-mandated restrictions. Although the authors accounted for many factors influencing the measurement of FIDs in birds, the authors did not achieve their aim of disentangling the effects of pandemic-specific ecological effects from ecological effects unrelated to the pandemic (such as habitat heterogeneity). Their findings indicate that FIDs are highly variable both within- and between- species, but do not strongly support the conclusion that FIDs did not change in urban species during the pandemic lockdown. Therefore, this study is of limited impact on our understanding of how a drastic change in human behaviour may impact bird behaviour in urban habitats. Overall, the study demonstrates the challenges in using FIDs as a general fear response in birds, even during a pandemic lockdown when fewer humans are presumably present, and this study illustrates the large degree of variation in FIDs in response to a human observer.

    1. Reviewer #3 (Public Review):

      A big open question in evolutionary biology is how single cells become multicellular organisms, capable of adaptation as a collective. Many cells form groups, but adaptation at the level of the group tends to be inefficient (especially in comparison to cells). Theoretically, it has been proposed that groups formed by clonal development (cells remain attached to each other after division) can more readily lead to group-level adaptation than groups coming together through the aggregation of different cells post-division. To evaluate empirically the plausibility of this hypothesis, the authors compared adaptation in two lines of yeast that differ only in a couple of mutations determining their mechanism of group formation. Ace2 mutants develop through staying together, and Floc mutants through aggregation. They performed a form of size selection (through settling) as a way to select for multicellularity (this selection regime has been used before to obtain multicellular phenotypes). This selective regime has two components: growing (largely due to differences between cells) and settling (largely due to differences between groups). Thus, the authors assume that increases in fitness through growth are due mostly to adaptation at the single-cell level, whereas increases in fitness through settling are mostly due to adaptation at the multicellular level. They find that adaptation in clonal groups is mostly through settling and that aggregative groups adapt more through growth (despite getting bigger).

      Overall this assumption makes sense (especially in a positive way) but growth, in this case, is also selecting against groups in the snowflake case and less strongly so in the floc case in which cells aggregate and disaggregate with some probability, and therefore cells can keep growing. That is, in addition to assortment the result is somewhat expected because there is less of a trade-off between growth and settling in floc: having a higher density in floc probably leads to higher aggregation and indirectly benefits settling, whereas in the clonal case, larger groups mean that a larger proportion of cells is not growing.

      The main result of the paper holds true: clonal development favors multicellular adaptation relative to aggregative multicellularity, but the reason is not exclusively a difference in the distribution of variation, but a difference in the trade-off between single cell and multicellular traits.

      In the second part of the paper, the authors beautifully show that the mechanisms of group formation affect evolutionary processes. Clonal aggregation leads to a decrease in the effective population size (because the descendants of mutants are likely to be in the same group, and therefore be selected together). This result shows that the mode of development can affect evolution!

    1. Reviewer #3 (Public Review):

      Summary:<br /> Smith-Magenis syndrome (SMS) is associated with obesity and is caused by deletion or mutations in one copy of the Rai1 gene which encodes a transcriptional regulator. Previous studies have shown that Bdnf gene expression is reduced in the hypothalamus of Rai1 heterozygous mice. This manuscript by Javed et al. further links SMS-associated obesity with reduced Bdnf gene expression in the PVH.

      Strengths:<br /> The authors show that deletion of the Rai1 gene in all BDNF-expressing cells or just in the PVH BDNF neurons postnatally caused obesity. Interestingly, mutant mice displayed sexual dimorphism in the cause for the obesity phenotype. Overall, the data are well presented and convincing except the data from LM22A-4.

      Weaknesses:<br /> 1. The most serious concern is about data from LM22A-4 administration experiments (Figure 5 and associated supplemental figures). A rigorous study has demonstrated that LM22A-4 does not activate TrkB (Boltaev et al., Science Signaling, 2017), which is consistent with unpublished results from many labs in the neurotrophin field. It is tricky to interpret body weight data from pharmacological studies because compounds always have some side effects, which can reduce body weight non-specifically.

      2. The resolution of all figures are poor, and thus I could not judge the quality of the micrographs.

      3. Citation of the literature is not precise. The study by An et al. (2015) shows that deletion of the Bdnf gene in the PVH leads to obesity due to increased food intake and reduced energy expenditure (not just hyperphagic obesity; Line 72). Furthermore, the study by Unger et al. (2017) carried out Bdnf deletion in the VMH and DMH using AAV-Cre and did not discuss SF1 neurons at all (Line 354). The two studies by Yang et al. (Mol Endocrinol, 2016) and Kamitakahara et al. (Mol Metab, 2015) did use SF1-Cre to delete the Bdnf gene and did not observe any obesity phenotype.

      4. Animal number is not described in many figure legends.

    1. Reviewer #3 (Public Review):

      This paper considers a challenging motor control task - the critical stability task (CST) - that can be performed equally well by humans and macaque monkeys. This task is of considerable interest since it is rich enough to potentially yield important novel insights into the neural basis of behavior in more complex tasks that point-to-point reaching. Yet it is also simple enough to allow parallel investigation in humans and monkeys, and is also easily amenable to computational modeling. The paper makes a compelling argument for the importance of this type of parallel investigation and the suitability of the CST for doing so.

      Behavior in monkeys and in human subjects suggests that behavior seems to cluster into different regimes that seem to either oscillate about the center of the screen, or drift more slowly in one direction. The authors show that these two behavioral regimes can be reliably reproduced by instructing human participants to either maintain the cursor in the center of the screen (position control objective), or keep the cursor still anywhere in the screen (velocity control objective) - as opposed to the usual 'instruction' to just not let the cursor leave the screen. A computational model based on optimal feedback control can similarly reproduce the two control regimes when the costs are varied

      Overall, this is a creative study that successfully leverages experiments in humans and computational modeling to gain insight into the nature of individual differences in behavior across monkeys (and people). The approach does work and successfully solves the core problem the authors set out to address. I do think that more comprehensive approaches might be possible that might involve, e.g. using a richer set of behavioral features to classify behavior, fitting a parametric class of control objectives rather than assuming a binary classification, and exploring the reliability of the inference process in more detail.

      In addition, the authors do fully establish that varying control objectives is the only way to obtain the different behavioral phenotypes observed. It may, for instance, be possible that some other underlying differences (e.g. the sensitivity to effort costs or the extent of signal-dependent noise) might also lead to a similar range of behaviors as varying the position versus velocity costs.

      Specific Comments:<br /> The simulations convincingly show that varying the control objective via the cost function can reproduce the different observed behavioral regimes. However, in principle, the differences in behavior among the monkeys and among the humans in Experiment 1 might not necessarily be due to difference in other aspects of the model. For instance, for a fixed cost function, differences in motor execution noise might perhaps lead the model to favor a position-like strategy or a velocity-like strategy. Or differences in the relative effort cost might alter the behavioral phenotype. Given that the narrative is about inferring control objectives, it seems important to rule out more systematically that some other factor might not potentially dictate each individual's style of performing the task. One approach to rule this out might be to try to formally fit the parameters of the model (or at least a subset of them) under a fixed cost function (e.g. velocity-based), and check whether the model might still recover the different regimes of behavior when parameters *other than the cost function* are varied.

      The approach to the classification problem is somewhat ad hoc and based on fairly simplistic, hand-picked features (RMS position and RMS velocity). I do wonder whether a more comprehensive set of behavioral features might enable a clearer separation between strategies, or might even reveal that the uninstructed subjects were doing something qualitatively different still from the instructed groups. Different control objectives ought to predict meaningfully different control policies - that is, different ways of updating hand position based on current state of the cursor and hand - e.g. the hand/cursor gain, which does clearly differ across instructed strategies. Would it be possible to distinguish control strategies more accurately based on this level of analysis, rather than based on gross task metrics? Might this point to possible experimental interventions (e.g. target jumps) that might validate the inferred objective?

      It seems that the classification problem cannot be solved perfectly, at least on a single-trial level. Although it works out that the classification can recover which participants were given which instructions, it's not clear how robust this classification is. It should be straightforward to estimate the reliability of the strategy classification by simulating participants and deriving a "confusion matrix", i.e. calculating how often e.g. data generated under a velocity-control objective gets mis-classified as following a position-control objective. It's not clear how this kind of metric relates to the decision confidence outputted by the classifier.

      The problem of inferring the control objective is framed as a dichotomy between position control and velocity control. In reality, however, it may be a continuum of possible objectives, based on the relative cost for position and velocity. How would the problem differ if the cost function is framed as estimating a parameter, rather than as a classification problem?

    1. https://www.attorneyatwork.com/analog-attorney-5-best-index-cards/

      Article about general usefulness of index cards written by a lawyer and for them, though not specific to them as a subgroup.

      Makes not of Nock's Dot-Dash cards which were apparently 3 x 5" dash gridded cards similar to Midori's grid notebooks. The website for the company is no longer active. Archived site: https://web.archive.org/web/20171007102414/https://nockco.com/paper/dotdash-3-x-5-note-cards

    1. Reviewer #3 (Public Review):

      This manuscript describes the use of scRNA-seq to decipher the cellular heterogeneity, molecular dynamics and signaling interactions during fibrocartilaginous enthesis formation. They delineate the enthesis growth and the temporal atlas from embryonic stage to postnatal stage by scRNA-seq, compared the development pattern of enthesis origins with tendon and articular cartilage, then demonstrated the cellular complexity and heterogeneity of postnatal enthesis growth and revealed the molecular dynamics and signaling networks during enthesis formation.

      This manuscript used appropriate and validated methodology in line with current state-of-the-art, and the conclusions of this paper are mostly well supported by data, more in vitro or in vivo experiments are encouraged to verify the key molecular dynamics and signaling networks revealed by scRNA-seq during enthesis formation.

      This manuscript facilitates better understand of the enthesis development, which will benefit the important field of enthesis research.

    1. Reviewer #3 (Public Review):

      The major claim from the paper is the dependence of two factors that determine the polymerization of MreB from a Gram-positive, thermophilic bacteria 1) The role of nucleotide hydrolysis in driving the polymerization. 2) Lipid bilayer as a facilitator/scaffold that is required for hydrolysis-dependent polymerization. These two conclusions are contrasting with what has been known until now for the MreB proteins that have been characterized in vitro. The experiments performed in the paper do not completely justify these claims as elaborated below.

      Major comments:

      1. No observation of filaments in the absence of lipid monolayer can also be accounted due to the higher critical concentration of polymerization for MreBGS in that condition. It is seen that all the negative staining without lipid monolayer condition has been performed at a concentration of 0.05 mg/mL. It is important to check for polymerization of the MreBGS at higher concentration ranges as well, in order to conclusively state the requirement of lipids for polymerization.

      2. The absence of filaments for the non-hydrolysable conditions in the lipid layer could also be because the filaments that might have formed are not binding to the planar lipid layer, and not necessarily because of their inability to polymerize.

      3. Given the ATPase activity measurements, it is not very convincing that ATP rather than ADP will be present in the structure. The ATP should have been hydrolysed to ADP within the structure. The structure is now suggestive that MreB is not capable of hydrolysis, which is contradictory to the ATP hydrolysis data.

    1. Reviewer #3 (Public Review):

      In this study, Ye et al investigated how a peptide that binds to the transmembrane (TM) domain of the T cell receptor (TCR) subunits affects TCR activation. The objective was to test the allosteric relaxation model of TCR activation. To this end, the authors leveraged their previously established strategy of designing TM-targeting peptides and studied how such peptide alters the TCR activation and downstream signaling cascades in Jurkat T cells. The authors found that the TM-targeting peptide inhibited phosphorylation of the TCR submits, phosphorylation of downstream signaling proteins such as ZAP70, and calcium influx in T cells. Using immunoprecipitation experiments, the authors proposed that the peptide binds into the membrane gap between CD3 and CD3 subunits in the TCR complex. The authors conclude that their data support the allosteric TCR activation model, in which allosteric changes in the TM bundle in the TCR complex determine the receptor signaling.

      The use of pH-responsive TM-targeting peptides, which the authors previously developed, is a novel aspect of this study. Those peptides can be quite powerful for understanding molecular mechanisms of receptor signaling, such as the allosteric activation model as tested in this study. The manuscript contains several interesting approaches and observations, but there are concerns about the experimental design and interpretation of the results. More importantly, the authors' primary conclusion that the allosteric changes in the TM bundles determine TCR activation is not fully supported by the data presented. For example:

      1. The authors provided confocal fluorescence images showing the colocalization of fluorescently labeled peptides and TCR subunits. Based on the data, they concluded that "PITCR is able to bind to TCR". This is misleading, because given the spatial resolution of the imaging technique, "colocalization" does not indicate binding or interaction between molecules. Because the peptide binding to the TM region is the pillar of the primary finding of this study, direct evidence supporting the peptide-TM binding or interaction is essential.<br /> 2. In calcium response experiments, the authors compared calcium influx (indicated by Indo-1 ratio) under different cell activation conditions (Figure 2). There are some concerns about how the authors interpreted the data: (1) The calcium plots from OKT3 activation in A-C panels are inconsistent. The plot in (A) showed a calcium peak after activation, which is not present in the plots shown in (B) and (C). There is no explanation or discussion on this inconsistency. (2) What is more concerning is that this prominent calcium peak in (A) was used to draw the conclusion that the designer peptide inhibitor effectively reduces calcium response. However, inconsistent with that conclusion, the calcium plots are indistinguishable for the three conditions: with PITCR (peptide inhibitor), with PITCRG41P (negative control that should not affect TCR activation), or no peptide. All three plots have similar magnetite and fluctuations. This does not support the authors' conclusion that the PITCR (peptide inhibitor) reduces calcium response in T cells.<br /> 3. Different types of T cells were used for separate measurements: E6-1 Jurkat T cells were used for calcium influx experiments, J. OT.hCD8+ Jurkat cells were used for CD69 measurements, and primary murine CD4+ T cells were used for colocalization imaging experiments. Rationales for the choices of cells in different measurements are also unclear. This is different from the common practice where different cell types are used in repeated experiments to test the generality of a finding. Here, they were used for different experiments, and findings were lumped together as "T cells", without further evidence/discussion on how translatable the findings from different cell types are.<br /> 4. The authors set out to test the model that TCR activation by pMHC occurs through allosteric changes in the TM region, but in most experiments, they activated Jurkat T cells by anti-CD3 antibody, not by antigen peptides. The anti-CD3 antibody activates TCR signaling through clustering. It is unclear whether TCR activation by anti-CD3 leads to the same allosteric changes in the TM region as activation by pMHC.

      As such, the main claim of the paper, namely that the designer peptide affects TCR signaling by disrupting the allosteric changes in the TM region, remains insufficiently supported by the data presented.

    1. Reviewer #3 (Public Review):

      Here the authors use high-parameter flow cytometry to address expression patterns of inhibitory receptors and concordant functional responses in CD8+ T cells from people living with HIV (PLWH) during early vs. long-term ART treatment in order to understand the potential evolution of exhausted T cells in HIV infection. High-dimensional bioinformatic analysis is employed to uncover different subsets of CD8+ T cells expressing TIM-3, TIGIT, PD1, LAG3, and CD39. Stimulation assays were further conducted to assess polyclonal T cell responses (superantigen) or HIV-gag-specific CD8+ T cells, and whether the responding cells displayed inhibitory receptors. Finally, inhibitory receptor blockade was used (focusing on TIGIT and TIM-3 only) to examine the potential reversal of exhaustion. The authors found that CD107a+ degranulating central memory T cells apparently were sensitive to TIGIT blockade, yielding increased responses in cells from ART-treated PLWH.

      Methods and Results Major Strengths: Sample size and data density. Longitudinal samples from long-term treated PLWH. Mechanistic studies to assess inhibitory receptor blockade.

      Methods and Results Major Weaknesses: Lack of clarity on flow cytometric analysis and statistical methodology, including correction for multiple comparisons. Clustering density in tSNE analysis is unjustified, leading to potentially spurious outcomes. Insufficient raw flow cytometry data presented on inhibitory receptor expression in the various contexts of the study to allow determination of whether the subsequent bioinformatic analysis was merited due to the very low expression of 3/5 markers examined. Unclear whether differences observed are biologically meaningful (despite statistical differences). Finally, although the longitudinal samples are a distinct strength of the study, changes over time within individuals are unfortunately not assessed.

      Aims and conclusions: The authors do find differences between the cohorts as described in the manuscript; however, the biological relevance of the findings is questionable due to an absence of direct studies on the cell populations found to be different. The use of unbiased clustering analysis is both a strength and a weakness. Specifically, the algorithm uncovers potential cell clusters that might be missed; however, the clustering program requires pre-set inputs on the expected number of clusters to be found, leading to possible irrelevant subsets being identified. The conclusions of the study are appropriately limited in scope.

      Impact: There have been numerous studies of CD8+ T cell inhibitory receptor expression and T cell exhaustion in the context of HIV infection. It is well-accepted that T-cell exhaustion is a hallmark of progressive infection. This study contributes to the current knowledge in this area specifically through the examination of very long-term ART-treated PLWH. Unfortunately, it is not clear that several of the examined inhibitory receptors could be adequately detected, limiting the interpretation of the findings. Finally, it is unclear that this study justifies the potential use of TIGIT blockade to improve T cell function given the unclear biological relevance of the differential populations of CD8+ T cells observed.

    1. Reviewer #3 (Public Review):

      Henault et al. address the important open question of whether hybridization could trigger TE mobilization. To do this they analysed MA lines derived from crosses of Saccharomyces paradoxus and Saccharomyces cerevisiae using long-read sequencing. These MA lines were already analysed in a previous publication using Illumina short-read data but the novelty of this work is the long-read sequencing data, which may reveal previously missed information. It is an interesting message of this study that hybridization between the two species did not lead to much TE activity. Due to this low activity, the authors performed an additional TE activity assay in vivo to measure transposition rates in hybrid backgrounds. The study is well written and I cannot spot any major problems. The study provides some important messages (like the influence of the genotype and mitochondrial DNA on transposition rates).

      Major comments<br /> - What I miss the most in this work is the perspective of the host defence against TEs in Saccharmoces. Based on such a mechanistic perspective, why do the authors think that hybridization could lead to a TE reactivation? For example, in Drosophila small RNAs important for the defence against a TE, are solely maternally transmitted. Hybrid offspring will thus solely have small-RNAs complementary to the TEs of the mother but not to the TEs of the father, therefore a reactivation of the paternal TEs may be expected. I was thus wondering, what is the situation in yeast. Why would we expect an upregulation of TEs? Without such a mechanistic explanation the hypothesis that TEs should be upregulated in hybrids is a bit vague, based on a hunch.

    1. Reviewer #3 (Public Review):

      In this manuscript, Gustison et al., describe the development of an automated whole-brain mapping pipeline, including the first 3D histological atlas of the prairie vole, and then use that pipeline to quantify Fos immunohistochemistry as a measure of neural activity during mating and pair bonding in male and female prairie voles. Prairie voles have become a useful animal model for examining the neural bases of social bonding due to their socially monogamous mating strategy. Prior studies have focused on identifying the role of a few neuromodulators (oxytocin, vasopressin, dopamine) acting in a limited number of brain regions. The authors use this unbiased approach to determine which areas become activated during mating, cohabitation, and pair bonding in both sexes to identify 68 brain regions clustered in seven brain-wide neuronal circuits that are activated over the course of pair bonding. This is an important study because i) it generates a valuable tool and analysis pipeline for other investigators in the prairie vole research community and ii) it highlights the potential involvement of many brain regions in regulating sexual behavior, social engagement, and pair bonding that have not been previously investigated.

      Strengths of the study include the unbiased assessment of neural activity using the automated whole brain activity mapped onto the 3D histological atlas. The design of the behavioral aspect of the study is also a strength. Brains were collected at baseline and 2.5, 6 and 22 hrs after cohabitation with either a sibling or opposite-sex partner. These times were strategically chosen to correspond to milestones in pair bond development. Behavior was also quantified during epochs over the 22 hr period providing useful information on the progression of behaviors (e.g. mating) during pair bonding and relating Fos activation to specific behaviors (e.g. sex vs bonding). The sibling co-housed group provided an important control, enabling the identification of areas specifically activated by sex and bond formation. The analyses of the data were rigorous, resulting in convincing conclusions. While there was nothing particularly surprising in terms of the structures that were identified to be active during the mating and cohabitation, the statistical analysis revealed interesting relationships in terms of interactions of the various clusters, and also some level of synchrony in brain activation between partners. Furthermore, ejaculation was found to be the strongest predictor of Fos activation in both males and females. The sex differences identified in the study were subtle and less than the authors expected, which is interesting.

      While the study provides a potentially useful tool and approach that may be of general use to the prairie vole community and identifies in an anatomically precise manner areas that may be important for mating or pair bond formation, there are some weaknesses as well. The study is largely descriptive. It is impossible to determine whether the activated areas are simply involved in sex or in the pair bond process itself. In other words, the authors did not use the Fos data to inform functional testing of circuits in pair bonding or mating behaviors. However, that is likely beyond the scope of this paper in which the goal was more to describe the automated, unbiased approach. This weakness is offset by the value of the comprehensive and detailed analysis of the Fos activation data providing temporal and precise anatomical relationships between brain clusters and in relation to behavior. The manuscript concludes with some speculative interpretations of the data, but these speculations may be valuable for guiding future investigations.

    1. Reviewer #3 (Public Review):

      Summary:<br /> The study by Karaś et al. reveals how multi-protein systems can evolve into single-protein equivalents, shedding light on the molecular events enabling gene loss during evolution. This work is valuable for researchers in evolutionary fields and offers potential applications in protein and organism engineering. While the findings lack broader appeal and societal implications, the evidence presented supports the proposed molecular mechanism. Using computational methods and biochemical analysis, the authors traced the evolutionary simplification of bacterial small heat shock proteins, linking specific mutations to functional changes. The study's strength lies in its vertical approach, identifying functional residues, but it does not introduce new techniques, limiting its novelty and significance.

      Strengths:<br /> 1) Experimental Approach<br /> The research question was clearly outlined and the author's approach to answering it was systematic. In particular, their model system was highly suitable to address the research question. The authors employed appropriate experimental and computational techniques, and their 'vertical approach' was beneficial in that it allowed them to discover functional residues in the sHsp system which may not have been possible otherwise. Overall, their approach to this study was solid.

      2) Reproducibility<br /> The results were presented well. The number of experimental repeats was suitable, as well as their analysis of the data. The values for standard deviation were reasonable, and their results using the alternative ancestors for the substrate aggregation assays helped support the robustness of their observations.

      Weaknesses:<br /> During the mutational experiments, the authors examined seven potential substitutions identified through ASR and measured their impact on protein disaggregation activity. Positions 66 and 109 exhibited a significant decrease in luciferase refolding stimulation. To explore the combined effect of these mutations, the authors created the double mutant AncA0. However, predicting the most impactful combination of mutations due to epistatic effects is challenging. A more effective strategy would be to test various combinations of mutations to identify the double mutant with the greatest decrease in luciferase refolding stimulation and/or alternatively perform a co-evolutionary study to try to understand any epistatic effects between the mutations.

    1. Reviewer #3 (Public Review):

      Summary:<br /> This study aimed to understand the neural correlates of memory recall over short (1-day) and long (14-days) intervals in children (5-7 years old) relative to young adults. The results show that children recall less than young adults and that this is accompanied by less activation (relative to young adults) in brain networks associated with memory retrieval.

      Strengths:<br /> This paper is one of few investigating long-term memory (multiple days) in a developmental population, an important gap in the field. Also, the authors apply a representational similarity analysis to understand how specific memories evolve over time. This analysis shows how the specificity of memories decreases over time in children relative to adults. This is an interesting finding.

      Weaknesses:<br /> Overall, these results are consistent with what we already know: recall is worse in children relative to adults (e.g., Cycowicz et al., 2001) and children activate memory retrieval networks to a lesser extent than adults (Bauer et al, 2017).

      It seems that the reduced activation in memory recall networks is likely associated with less depth of memory encoding in children due to inattentiveness, reduced motivation, and documented differences in memory strategies. In regards to this, there was consideration of IQ, sex, and handedness but these were not included as covariates as they were not significant although I note p<.16 suggests there was some level of association nonetheless. Also, IQ is measured differently for the children and adults so it's not clear these can be directly contrasted. The authors suggest the instructed elaborative encoding strategy is effective for children and adults but the reference in support of this (Craik & Tulving, 1975) does not seem to support this point.

    1. Reviewer #3 (Public Review):

      Overall, this is a strong manuscript that uses multiple current techniques to provide specific mechanistic insight into prior discoveries of the contributions of the Bcl11b transcription factor to mossy fiber synapses of dentate gyrus granule cells. The authors employ an adult deletion of Bcl11b via Tamoxifen-inducible Cre and use immunohistochemical, electron microscopy, and electrophysiological studies of synaptic plasticity, together with viral rescue of C1ql2, a direct transcriptional target of Bcl11b or Nrxn3, to construct a molecular cascade downstream of Bcl11b for DG mossy fiber synapse development. They find that C1ql2 re-expression in Bcl11b cKOs can rescue the synaptic vesicle docking phenotype and the impairments in MF-LTP of these mutants. They also show that C1ql2 knockdown in DG neurons can phenocopy the vesicle docking and plasticity phenotypes of the Bcl11b cKO. They also use artificial synapse formation assays to suggest that C1ql2 functions together with a specific Nrxn3 splice isoform in mediating MF axon development, extending these data with a C1ql2-K262E mutant that purports to specifically disrupt interactions with Nrxn3. All of the molecules involved in this cascade are disease-associated and this study provides an excellent blueprint for uncovering downstream mediators of transcription factor disruption. Together this makes this work of great interest to the field. Strengths are the sophisticated use of viral replacement and multi-level phenotypic analysis while weaknesses include the linkage of C1ql2 with a specific Nrxn3 splice variant in mediating these effects.

      Here is an appraisal of the main claims and conclusions:

      1. C1ql2 is a downstream target of Bcl11b which mediates the synaptic vesicle recruitment and synaptic plasticity phenotypes seen in these cKOs. This is supported by the clear rescue phenotypes of synapse anatomy (Fig.2) and MF synaptic plasticity (Fig.3). One weakness here is the absence of a control assessing over-expression phenotypes of C1ql2. It's clear from Fig.1D that viral rescue is often greater than WT expression (totally expected). In the case where you are trying to suppress a LoF phenotype, it is important to make sure that enhanced expression of C1ql2 in a WT background does not cause your rescue phenotype. A strong overexpression phenotype in WT would weaken the claim that C1ql2 is the main mediator of the Bcl11b phenotype for MF synapse phenotypes.

      2. Knockdown of C1ql2 via 4 shRNAs is sufficient to produce the synaptic vesicle recruitment and MF-LTP phenotypes. This is supported by clear effects in the shRNA-C1ql2 groups as compared to nonsense-EGFP controls. One concern (particularly given the use of 4 distinct shRNAs) is the potential for off-target effects, which is best controlled for by a rescue experiment with RNA-insensitive C1ql2 cDNA as opposed to nonsense sequences, which may not elicit the same off-target effects.

      3. C1ql2 interacts with Nrxn3(25b+) to facilitate MF terminal SV clustering. This claim is theoretically supported by the HEK cell artificial synapse formation assay (Fig.5), the inability of the K262-C1ql2 mutation to rescue the Bcl11b phenotype (Fig.6), and the altered localization of C1ql2 in the Nrxn1-3 deletion mice (Fig.7). Each of these lines of experimental evidence has caveats that should be acknowledged and addressed. Given the hypothesis that C1ql2 and Nrxn3b(25b) are expressed in DG neurons and work together, the heterologous co-culture experiment seems strange. Up till now, the authors are looking at pre-synaptic function of C1ql2 since they are re-expressing it in DGNs. The phenotypes they are seeing are also pre-synaptic and/or consistent with pre-synaptic dysfunction. In Fig.5, they are testing whether C1ql2 can induce pre-synaptic differentiation in trans, i.e. theoretically being released from the 293 cells "post-synaptically". But the post-synaptic ligands (Nlgn1 and and GluKs) are not present in the 293 cells, so a heterologous synapse assay doesn't really make sense here. The effect that the authors are seeing likely reflects the fact that C1ql2 and Nrxn3 do bind to each other, so C1ql2 is acting as an artificial post-synaptic ligand, in that it can cluster Nrxn3 which in turn clusters synaptic vesicles. But this does not test the model that the authors propose (i.e. C1ql2 and Nrxn3 are both expressed in MF terminals). Perhaps a heterologous assay where GluK2 is put into HEK cells and the C1ql2 and Nrxn3 are simultaneously or individually manipulated in DG neurons?

      4. K262-C1ql2 mutation blocks the normal rescue through a Nrxn3(25b) mechanism (Fig.6). The strength of this experiment rests upon the specificity of this mutation for disrupting Nrxn3b binding (presynaptic) as opposed to any of the known postsynaptic C1ql2 ligands such as GluK2. While this is not relevant for interpreting the heterologous assay (Fig.5), it is relevant for the in vivo phenotypes in Fig.6. Similar approaches as employed in this paper can test whether binding to other known postsynaptic targets is altered by this point mutation.

      5. Altered localization of C1ql2 in Nrxn1-3 cKOs. These data are presented to suggest that Nrx3(25b) is important for localizing C1ql2 to the SL of CA3. Weaknesses of this data include both the lack of Nrxn specificity in the triple a/b KOs as well as the profound effects of Nrxn LoF on the total levels of C1ql2 protein. Some measure that isn't biased by this large difference in C1ql2 levels should be attempted (something like in Fig.1F).

    1. Reviewer #3 (Public Review):

      This study demonstrates that from fish to mammals CIB2/3 is required for hearing, revealing the high degree of conservation of CIB2/3 function in vertebrate sensory hair cells. The modeling data reveal how CIB2/3 may affect the conductance of the TMC1/2 channels that mediate mechanotransduction, which is the process of converting mechanical energy into an electrical signal in sensory receptors. This work will likely impact future studies of how mechanotransduction varies in different hair cell types.

      One caveat is that the experiments with the mouse mutants are confirmatory in nature with regard to a previous study by Wang et al., and the authors use lower resolution tools in terms of function and morphological changes. Another is that the modeling data is not supported by electrophysiological experiments, however, as mentioned above, future experiments may address this weakness.

    1. Reviewer #3 (Public Review):

      Summary:<br /> Using ex vivo electrophysiology and morphological analysis, Boi et al. investigate the electrophysiological and morphological properties of serotonergic and dopaminergic subpopulations in the dorsal raphe nucleus (DRN). They performed labor-intensive and rigorous electrophysiology with posthoc immunohistochemistry and neuronal reconstruction to delineate the two major cell classes in the DRN: DRN-DA and DRN-5HT, named according to their primary neurotransmitter machinery. They find that the dopaminergic (DRN-DA) and serotonergic (DRN-5HT) neurons are electrophysiologically and morphologically distinct, and are altered following striatal injection of the toxin 6-OHDA. However, these alterations were largely prevented in DRN-5HT neurons by pre-treatment with desipramine. These findings suggest an important interplay between catecholaminergic systems in healthy and parkinsonian conditions, as well as a relationship between neuronal structure and function.

      Strengths:<br /> A large, well-validated dataset that will be a resource for others.<br /> Complementary electrophysiological and anatomical characterizations.<br /> Conclusions are justified by the data.<br /> Relevant for basic scientists interested in DRN cell types and physiology.<br /> Relevant for those interested in serotonin and/or DRN neurons in Parkinson's Disease.

      Weaknesses:<br /> Given the scope of the author's questions and hypotheses, I did not identify any major weaknesses.

    1. Reviewer #3 (Public Review):

      Ghasemahmad et al. examined behavioral and neurochemical responses of male and female mice to vocalizations associated with mating and restraint. The authors made two significant and exciting discoveries. They revealed that the affective content of vocalizations modulated both behavioral responses and the release of acetylcholine (ACh) and dopamine (DA) but not serotonin (5-HIAA) in the basolateral amygdala (BLA) of male and female mice. Moreover, the results show sex-based differences in behavioral responses to vocalizations associated with mating. The authors conclude that behavior and neurochemical responses in male and female mice are experience-dependent and are altered by vocalizations associated with restraint and mating. The findings suggest that ACh and DA release may shape behavioral responses to context-dependent vocalizations. The study has the potential to significantly advance our understanding of how neuromodulators provide internal-state signals to the BLA while an animal listens to social vocalizations; however, multiple concerns must be addressed to substantiate their conclusions.

      Major concerns:

      1. The authors normalized all neurochemical data to the background level obtained from a single pre-stimulus sample immediately preceding playback. The percentage change from the background level was calculated based on a formula, and the underlying concentrations were not reported. The authors should report the sample and background concentrations to make the results and analyses more transparent. The authors stated that NE and 5-HT had low recovery from the mouse brain and hence could not be tracked in the experiment. The authors could be more specific here by relating the concentrations to ACh, DA, and 5-HIAA included in the analyses.

      2. For the EXP group, the authors stated that each animal underwent 90-min sessions on two consecutive days that provided mating and restraint experiences. Did the authors record mating or copulation during these experiments? If yes, what was the frequency of copulation? What other behaviors were recorded during these experiences? Did the experiment encompass other courtship behaviors along with mating experiences? Was the female mouse in estrus during the experience sessions?

      3. For the mating playback, the authors stated that the mating stimulus blocks contained five exemplars of vocal sequences emitted during mating interactions. The authors should clarify whether the vocal sequences were emitted while animals were mating/copulating or when the male and female mice were inside the test box. If the latter was the case, it might be better to call the playback "courtship playback" instead of "mating playback".

      4. Since most differences that the authors reported in Figure 3 were observed in Stim 1 and not in Stim 2, it might be better to perform a temporal analysis - looking at behaviors and neurochemicals over time instead of dividing them into two 10-minute bins. The temporal analysis will provide a more accurate representation of changes in behavior and neurochemicals over time.

      5. In Figures 2 and 3, the authors show the correlation between Flinching behavior and ACh concentration. The authors should report correlations between concentrations of all neurochemicals (not just ACh) and all behaviors recorded (not just Flinching), even if they are insignificant. The analyses performed for the stim 1 data should also be performed on the stim 2 data. Reporting these findings would benefit the field.

      6. The mice used in the study were between p90 - p180. Although CBA/CaJ mice display normal hearing, sexual behaviors, and social behaviors for at least 1 year (Ohlemiller, Dahl, and Gagnon, JARO 11: 605-623, 2010), the age of the mice covers a range of 90 days. It would strengthen the authors' argument that the affective content of vocalizations modulated both behavioral responses and the release of acetylcholine (ACh) and dopamine (DA) but not serotonin (5-HIAA) in the basolateral amygdala (BLA) of male and female mice if there were no correlations between the magnitude of the neural responses and age.

      7. The authors reported neurochemical levels estimated as the animals listened to the sounds played back. What about the sustained effects of changes in neurochemicals? Are there any potential long-term effects of social vocalizations on behavior and neurochemical levels? The authors might consider discussing long-term effects.

      8. Histology from a single recording was shown in supplementary figure 1. It would benefit the readers if additional histology was shown for all the animals, not just the colored schematics summarizing the recording probe locations. Further explanation of the track location is also needed to help the readers. Make it clear for the readers which dextran-fluorescein labeling image is associated with which track in the schematic.

      9. The authors did not control for the sounds being played back with a speaker. This control may be necessary since the effects are more pronounced in Stim 1 than in Stim 2. Playing white noise rather than restraint or courtship vocalizations would be an excellent control. However, the authors could perform a permutation analysis and computationally break the relationship between what sound is playing and the neurochemical data. This control would allow the authors to show that the actual neurochemical levels are above or below chance.

      10. The authors indicated that each animal's post-vocalization session was also recorded. No data in the manuscript related to the post-vocalization playback period was included. This omission was a missed opportunity to show that the neurochemical levels returned to baseline, and the results were not dependent on the normalization process described in major concern #1. The data should be included in the manuscript and analyzed. It would add further support for the model described in Figure 6.

      11. The authors could use a predictive model, such as a binary classifier trained on the CSF sampling data, to predict the type of vocalizations played back. The predictive model could support the conclusions and provide additional support for the model in Figure 6.

    1. Reviewer #3 (Public Review):

      Using the zebrafish model, this paper by Kraus A. et al., described the anti-virus response in the Olfactory bulb (OB) neurons and microglia. This paper used the behavioral test, neuron calcium imaging, and single-cell transcriptomic analysis. Importantly, this paper discovered that following IHNV infection, the OB neuron increased Pacap expression, which likely protects the neuron cells and mediates the anti-viral defense response. Overall, the findings presented in this paper are quite interesting.

      Major strength:<br /> (1) The author demonstrated for the first time that zebrafish OSN neurons sense the IHNV viruses and transmit the viral signal to OB neurons. The zebrafish can be used as a new system to investigate the viral-neuron interaction and understand the mechanisms of how the neurons in the CNS to viral infection through the peripheral chemosensory system.

      (2) This paper generated the first zebrafish OB sc-RNA sequencing data. The sc-RNA sequencing data generated in this paper will also help other zebrafish researchers who study the OB neurons.

      Major weakness:<br /> The experiment results presented in this paper are not well-integrated. For example, it is unclear how the behavioral phenotype is connected to the neuronal calcium phenotype. It is also unclear how the behavioral or neuronal calcium imaging results is connected to the scRNA sequencing result.

    1. Reviewer #3 (Public Review):

      This manuscript aims to exploit experimental measurements of the extracellular voltages produced by colliding action potentials to adjust a simplified model of action potential propagation that is then used to predict the extracellular fields at axon terminals. The overall rationale is that when solving the cable equation (which forms the substrate for models of action potential propagation in axons), the solution for a cable with a closed end can be obtained by a technique of superposition: a spatially reflected solution is added to that for an infinite cable and this ensures by symmetry that no axial current flows at the closed boundary. By this method, the authors calculate the expected extracellular fields for axon terminals in different situations. These fields are of potential interest because, according to the authors, their magnitude can be larger than that of a propagating action potential and may be involved in ephaptic signalling. The authors perform direct measurements of colliding action potentials, in the earthworm giant axon, to parameterise and test their model.

      Although simplified models can be useful and the trick of exploiting the collision condition is interesting, I believe there are several significant problems with the rationale, presentation, and application, such that the validity and potential utility of the approach is not established.

      Simplified model vs. Hogdkin and Huxley<br /> The authors employ a simplified model that incorporates a two-state membrane (in essence resting and excited states) and adds a recovery mechanism. This generates a propagating wave of excitation and key observables such as propagation speed and action potential width (in space) can be adjusted using a small number of parameters. However, even if a Hodgkin-Huxley model does contain a much larger number of parameters that may be less easy to adjust directly, the basic formalism is known to be accurate and typical modifications of the kinetic parameters are very well understood, even if no direct characterisations already exist or cannot be obtained. I am therefore unconvinced by the utility of abandoning the Hodgkin-Huxley version.

      In several places in the manuscript, the simplified model fits the data well whereas the Hodgkin-Huxley model deviates strongly (e.g. Fig. 3CD). This is unsatisfying because it seems unlikely that the phenomenon could not be modelled accurately using the HH formulation. If the authors really wish to assert that it is "not suitable to predict the effects caused by AP [collision]" (p9) they need to provide a good deal more analysis to establish the mechanism of failure.

      (In)applicability of the superposition principle<br /> The reflecting boundary at the terminal is implemented using the symmetry of the collision of action potentials. However, at a closed cable there is no reflecting boundary in the extracellular space and this implied assumption is particularly inappropriate where the extracellular field is one objective of the modelling, as here. I believe this assumption is not problematic for the calculation of the intracellular voltage, because extracellular voltage gradients can usually be neglected, but the authors need to explain how the issue was dealt with for the calculation of the extracellular fields of terminals. I assume they were calculated from the membrane currents of one-half of the collision solution, but this does not seem to be explained. It might be worth showing a spatial profile of the calculated field.

      Missing demonstrations<br /> Central analytical results are stated rather brusquely, notably equations (3) and (4) and the relation between them. These merit an expanded explanation at the least. A better explanation of the need for the collision measurements in parameterising the models should also be provided.

      Adjusted parameters<br /> I am uncomfortable that the parameters adjusted to fit the model are the membrane capacitance and intracellular resistance. These have a physical reality and could easily be measured or estimated quite accurately. With a variation of more than 20-fold reported between the different models in Appendix 2 we can be sure that some of the models are based upon quite unrealistic physical assumptions, which in turn undermines confidence in their generality.

      p8 the values of both the extracellular (100 Ohm m) and intracellular resistivity (1 Ohm m) appear to be in error, especially the former.

      (In)applicability to axon terminals<br /> The rationale of the application of the collision formalism to axon terminals is somewhat undermined by the fact that they tend not to be excitable. There is experimental evidence for this in the Calyx of Held and the cerebellar pinceau. The solution found via collision is therefore not directly applicable in these cases.

      Comparison with experimental data<br /> More effort should be made to compare the modelling with the extracellular terminal fields that have been reported in the literature.

      Choice of term "annihilation"<br /> The term annihilation does not seem wholly appropriate to me. The dictionary definitions are something along the lines of complete destruction by an external force or mutual destruction, for example of an electron and a positron. I don't think either applies exactly here. I suggest retaining the notion of collision which is well understood in this context.

    1. Reviewer #3 (Public Review):

      The authors utilize chimpanzee-human hybrid cell lines to assess cis-regulatory evolution. These hybrid cell lines offer a well-controlled environment, enabling clear differentiation between cis-regulatory effects and environmental or other trans effects.<br /> In their research, Wang et al. expand the range of chimpanzee-human hybrid cell lines to encompass six new developmental cell types derived from all three germ layers. This expansion allows them to discern cell type-specific cis-regulatory changes between species from more pleiotropic ones. Although the study investigates only two iPSC clones, the RNA- and ATAC-seq data produced for this paper is a valuable resource.

      The authors begin their analysis by examining the relationship between allele-specific expression (ASE) as a measure of species divergence and cell type specificity. They find that cell-type-specific genes exhibit more divergent expression. By integrating this data with measures of constraint within human populations, the authors conclude that the increased divergence of tissue-specific genes is, at least in part, attributable to positive selection. A similar pattern emerges when assessing allele-specific chromatin accessibility (ASCA) as a measure of divergence of cis-regulatory elements (CREs) in the same cell lines.

      By correlating these two measures, the authors identify 95 CRE-gene pairs where tissue-specific ASE aligns with tissue-specific ASCA. Among these pairs, the authors select two genes of interest for further investigation. Notably, the authors employ an intriguing machine-learning approach in which they compare the inferred chromatin state of the human sequence with that of the chimpanzee sequence to pinpoint putatively causal variants.

      Overall, this study delves into the examination of gene expression and chromatin accessibility within hybrid cell lines, showcasing how this data can be leveraged to identify potential causal sequence differences underlying between-species expression changes.

      I have three major concerns regarding this study:

      1. The only evidence that the cells are indeed differentiated in the right direction is the expression of one prominent marker gene per cell type. Especially for the comparison of conservation between the differentiated cell types, it would be beneficial to describe the cell type diversity and the differentiation success in more detail.

      2. Check for a potential confounding effect of sequence similarity on the power to detect ASE or ASCA.

      3. In the last part the authors showcase 2 examples for which the log2 fold changes in chromatin state scores as inferred by the machine learning model Sei are used. This is an interesting and creative approach, however, more sanity checks on this application are necessary.

    1. Reviewer #3 (Public Review):

      The manuscript by Bimai et al describes a structural and functional characterization of an anaerobic ribonucleotide reductase (RNR) enzyme from the human microbe, P. copri. More specifically, the authors aimed to characterize the mechanism by how (d)ATP modulates nucleotide reduction in this anaerobic RNR, using a combination of enzyme kinetics, binding thermodynamics, and cryo-EM structural determination. One of the principal findings of this paper is the ordering of a NxN 'flap' in the presence of ATP that promotes RNR catalysis and the disordering of both this flap and the glycyl radical domain (GRD) when the inhibitory effector, dATP, binds. The latter is correlated with a loss of substrate binding, which is the likely mechanism for dATP inhibition. It is important to note that the GRD is remote (>30 Ang) from the binding site of the dATP molecule, suggesting long-range communication of the structural (dis)ordering. The authors also present evidence for a shift in oligomerization in the presence of dATP. The work does provide evidence for new insights/views into the subtle differences of nucleotide modulation (allostery) of RNR through long-range interactions.

      The strengths of the work are the impressive, in-depth structural analysis of the various regulated forms of PcRNR by (d)ATP using cryo-EM. The authors present seven different models in total, with striking differences in oligomerization and (dis)ordering of select structural features, including the GRD that is integral to catalysis. The authors present several, complementary biochemical experiments (ITC, MST, EPR, kinetics) aimed at resolving the binding and regulatory mechanism of the enzyme by various nucleotides. The authors present a good breadth of the literature in which the focus of allosteric regulation of RNRs has been on the aerobic orthologues.

      Given the resolution of some of the structures in the remote regions that appear to be of importance, the rigor of the work could have been improved by complementing this experimental studies with molecular dynamics (MD) simulations to reveal the dynamics of the GRD and loops/flaps at the active site. The biochemical data supporting the loss of substrate binding with dATP association is compelling, but the binding studies of the (d)ATP regulatory molecules are not; the authors noted less-than-unity binding stoichiometries for the effectors. Also, the work would benefit from additional support for oligomerization changes using an additional biochemical/biophysical approach.

      Overall, the authors have mostly achieved their overall aims of the manuscript. With focused modifications, including additional control experiments, the manuscript should be a welcomed addition to the RNR field.

    1. Reviewer #3 (Public Review):

      Light harvesting (LH) associated with photosynthesis, photoprotection, and the formation of useful pigment-protein complexes are all major functions of carotenoid (Car) pigments. However, the connections between quinone exchange, prokaryotic reaction center (RC)-LH complex formation, and Car depletion in the LH are not entirely understood. This article examined the native RC-LH (nRC-LH) and Car-depleted RC-LH (dRC-LH) complexes in the filamentous anoxygenic phototroph Roseiflexus castenholzii. The authors show with a high degree of detail using crystallography and Cryo-EM complemented with biophysical techniques important results of a new conformation of a LH. They could assigned the amino acid sequences of subunit X and two hypothetical proteins, Y and Z, that formed the quinone channel and maintained the RC-LH connections. This study identifies a new architectural basis for the regulation of bacterial RC-LH complex and quinone exchange by Cars assembly, which is distinct from the well known purple bacteria. These findings represent a significant advancement of diversity and development of bacterial photosynthetic machinery.

    1. Reviewer #3 (Public Review):

      The present paper uncovers evidence of the coordination of two brain areas involved in a two-step learning process in birdsong plasticity. Indeed, songbirds can modify their song based on an error-correction mechanism that involves a motor bias expressed by a basal ganglia-thalamo-cortical loop. After training (hundreds or a few thousands of renditions), the motor bias necessary to correct vocal errors becomes independent of the BG-thalamo-cortical loop and is transferred into the long-term motor program stored in a primary motor network. Current understanding claims that the output nucleus of the BG-thalamo-cortical loop, LMAN, trains the primary motor networks (in area RA) to drive the learning transfer. However, no clear evidence for such entrainment was available until now. In the present study, the authors elegantly show that correlations in trial-by-trial fluctuations in the premotor activity in LMAN and RA are present spontaneously (in multi-unit electrophysiological recordings) and are increased during a lab-induced plasticity protocol. The change in correlation is specific to the syllable that undergoes plasticity. Moreover, perturbing LMAN activity through low-intensity and spatially broad electrical stimulation of LMAN during the premotor window prevents behavioral adaptation. Altogether, their results convincingly show that the entrainment of RA neural populations by LMAN neurons is present during baseline, strengthened during plasticity in a syllable-specific manner, and necessary for song plasticity.

      This study thus provides important validation of the current model for the 2-step learning process underlying song learning and plasticity, where a BG-thalamo-cortical network drive motor bias to correct vocal errors based on a reinforcement learning mechanism, while the song motor engram is updated slowly through the adjustment of song-related activity in the primary motor areas. Beyond the songbird field, these results will be of importance to all studying sensorimotor learning and adaptation, and more broadly the formation of memory through a two-step learning process.

      The authors present the context for their hypothesis clearly, state their hypothesis precisely, and conduct a thorough investigation of the posed question. The conclusions are well supported by data.

      In particular, the statistical evaluation of the covariance of LMAN and RA activity in the premotor window is adequate and the interpretation of the results is therefore well backed by their analysis. The methods used here to assess covariation between LMAN and RA activity during singing set the ground for future studies looking at the coordination between brain areas during behavior.

    1. Reviewer #3 (Public Review):

      Jie Yang et al. investigated the transgenerational behavioral modification of a high-sugar diet (HSD) in Drosophila and revealed the underlying molecular and neural mechanisms. It has been reported that HSD exposure decreases sweet sensitivity in gustatory sensory neurons, resulting in reduced sugar response (Proboscis extension reflex, PER) in flies. The current study reports that this effect can be transmitted across generations through the maternal germline. Furthermore, the authors show that H3K27me3 modification is enhanced in the first-generation progenies of HSD-treated flies (F1), and genetical or pharmacological disruption of PCL-PRC2 complex blocks the behavioral change and restores the sweet sensitivity in the Gr5a+ sweet sensory neurons. The authors further analyze the differentially expressed genes in the F1 flies. Among H3K27me3 hypermethylated regions, they focus on homeobox genes and find a transcription factor Caudal (Cad), which shows decreased expression in the F1 flies. Knocking down Cad in Gr5a+ neurons results in decreased PER response to sucrose.

      Transgenerational changes in physiology and metabolism have been broadly studied, while inherited changes at the behavioral level are much less investigated. This work provides convincing evidence for transgenerational modification of feeding behavior and digs out the underlying molecular and neural mechanisms. However, there still are several concerns that need to be clarified.

      1) The epigenetic regulator PCR2 has been found to play an essential role in the 7d-HSD-induced modification of the PER response. In this study, it's important to clarify for the transgenerational change, whether epigenetic modification is required in the flies exposed to HSD (F0), the progenies (F1), or both. It would be very helpful for better interpretation if the procedures of HSD treatment in RNAi experiments and the drug treatments were stated in more detail. In addition, the F0 flies should be examined as the control.<br /> 2) The information on the drug treatment period is also missing for imaging experiments (Fig.4C). Moreover, the response curve is very different from those recorded in the same neurons in previous studies. What's the reason? Please also provide a representative image showing which part of the Gr5a neurons is recorded.<br /> 3) It's unclear whether the decreased Cad expression upon HSD treatment specifically occurred in Gr5a+ neurons or a lot of cells. If the change in gene expression is significant in the qPCR test, it should occur in a large number of cells, most likely including different types of gustatory sensory neurons. If lower cad expression led to lower neural response and thereby lower behavioral response, how to specifically decrease the PER response to sucrose but not to other tastes? --whether HSD-induced desensitization is specific to sucrose in the offspring?<br /> 4) In Fig.2D, data are sorted for genomic regions showing an up-regulated modification of H3K27me. It's unclear whether similar sorting was performed in panel C. This needs to be clarified.

    1. Reviewer #3 (Public Review):

      The authors aim to gain a more comprehensive understanding of the role of FIKK4.1 in parasite biology. To achieve this, they used a novel approach termed PerTurboID that allows them to map changes in the conformational and interaction environment of proteins that are in close proximity of the tagged gene of interest. Here the authors focus on two proteins KHARP and PTP4 who are known targets of FIKK4.1 and assessed the impact of the genetic disruption of the kinase on the interaction environment of these proteins. The experimental strategy identifies a range of changes that indicate that changes go beyond the direct targets of FIKK4.1 and therefore creates new insights of interaction networks that are regulated by this specific kinase.

      The strength of this approach is not only that it can identify new interaction networks relating to FIKK4.1 but that serves as a proof of concept that can be used for a wide range of applications in parasite biology. At the same time as the authors have noted themselves the extent of the biotin pulse is important and most likely needs to be calibrated for every specific application. In addition, this approach is only suitable for proteins that can be tagged without impacting their function.

      The authors present very convincing evidence that the PerTurboID is suitable to study FIKK kinases in parasites and have used this to shed new light on how FIKK4.1 is involved directly or indirectly in a wider range of biological activities in the parasite.

      The main impact of this work is that it provides a wider understanding of the relationship between a specific kinase and structural as well as biological consequences. The methodology is also very powerful and will have a wide range of applications.

    1. Reviewer #3 (Public Review):

      Summary:<br /> The authors present a biophysically detailed model of the basolateral amygdala (BLA) that is capable of fear learning through a depression-dominated spike-timing dependent plasticity (STDP) mechanism. Furthermore, the model also replicates experimentally measured rhythmic signatures of baseline amygdala activity and changes of these signatures during and after fear learning. The authors furthermore carefully dissect the contributions of the three different types of interneurons (parvalbumin-positive (PV), somatostatin-positive (SOM), and vaso-active peptide-positive (VIP) interneurons) in regulating network activity to allow for the association between conditioned and unconditioned stimuli.

      Strengths:<br /> The biophysical detail of the model allows the authors to go beyond a simple modelling of the fear learning process in terms of spiking activity of the principal cells and to link the associative learning to several oscillatory rhythms in the BLA, namely high and low theta and gamma rhythms. This provides an understanding of the generation and function of these rhythms in the baseline amygdala circuit as well as of the functional consequences of alterations of these rhythms during and after the fear learning process. This offers a new and uniquely detailed insight into the mechanistic level.

      Weaknesses:<br /> The main weakness of the approach is the lack of experimental data from the BLA to constrain the biophysical models. This forces the authors to use models based on other brain regions and leaves open the question of whether the model really faithfully represents the basolateral amygdala circuitry. Furthermore, the authors chose to use model neurons without a representation of the morphology. However, given that PV and SOM cells are known to preferentially target different parts of pyramidal cells and given that the model relies on a strong inhibition form SOM to silence pyramidal cells, the question arises whether SOM inhibition at the apical dendrite in a model representing pyramidal cell morphology would still be sufficient to provide enough inhibition to silence pyramidal firing. Lastly, the fear learning relies on the presentation of the unconditioned stimulus over a long period of time (40 seconds). The authors justify this long-lasting input as reflecting not only the stimulus itself but as a memory of the US that is present over this extended time period. However, the experimental evidence for this presented in the paper is only very weak.

      The authors achieved the aim of constructing a biophysically detailed model of the BLA not only capable of fear learning but also showing spectral signatures seen in vivo. The presented results support the conclusions with the exception of a potential alternative circuit mechanism demonstrating fear learning based on a classical Hebbian (i.e. non-depression-dominated) plasticity rule, which would not require the intricate interplay between the inhibitory interneurons. This alternative circuit is mentioned but a more detailed comparison between it and the proposed circuitry is warranted.

      The presented model demonstrates how the complex interplay between different types of interneurons is able to precisely control neural activity to enable learning to happen. Furthermore, the presented work shows this interactive control of activity by the interneurons gives rise to specific oscillatory signatures. Since the three types of interneurons considered here are found throughout the brain, the findings will likely have a big impact on other studies of interneuron function and learning in general.

    1. Reviewer #3 (Public Review):

      In the present study, Iversen et al investigate the effect of middle cerebral artery occlusion (MCAo) on penumbral capillary blood flow in rat brains. Using Laser Speckle Contrast imaging and two-photon microscopy, they found that during MCAo the red blood cell dynamics become chaotic in penumbral capillaries despite an apparent constant residual blood flow. They further conclude that these disturbances would cause decreases in steady-state cerebral metabolic rate of oxygen (CMRO2), and tissue oxygen tension (PtO2) using a post hoc biophysical model for oxygen extraction. Interestingly, the authors present data excluding a role for pericytes in altering capillary blood flow. From this observation, the study raises potentially interesting questions on the origin of the disturbance but fails to address them by not investigating the upstream arteriolar behavior. Increased vasomotion, palpability, or intermittent vasospasm may trigger capillary blood flow disturbances without necessarily impacting residual blood flow resting as measured by Laser Speckle Contrast imaging. Furthermore, the data are very poorly presented, here are some examples:<br /> Fig 1b is incorrectly labeled and, assuming this is the "first" 1f panel, the scale bar shows 500 µm while the legend says 200.<br /> Fig 1d is poorly convincing as pink or grey, as detailed in the legend, are not visible. It also looks like there is a second core and penumbra on the more rostral left part of the brain.<br /> Line 219 time is misspelled.<br /> Fig 2, what does "percent of alle capillaries" on the y axes mean? 2d is presented before 2c in the text.<br /> What is the rationale for presenting the statistics from Fig 3 in Fig 4? Panels 4e and 4f are not discussed. The reference in the Fig 4 legend is not formatted.<br /> Fig 6 is presented before Fig 5.<br /> The overall lack of a central hypothesis combined with the aforementioned weaknesses prevents the study from achieving its proposed goal "to characterize microvascular flow disturbances in penumbral tissue in a rat model of acute ischemic stroke".

    1. Reviewer #3 (Public Review):

      Summary:<br /> Bidirectional transsynaptic signaling via cell adhesion molecules and cell surface receptors contributes to the remarkable specificity of synaptic connectivity in the brain. Zaman et al., investigate how the receptor tyrosine kinase Kit and its trans-cellular kit ligand regulate molecular layer interneuron (MLI)- Purkinje cell (PC) connectivity in the cerebellum. Presynaptic Kit is specific for MLIs, and forms a trans-synaptic complex with Kit ligand in postsynaptic PC cells. The authors begin by generating Kit cKOs via an EUCOMM allele to enable cell-type specific Kit deletion. They cross this Kit cKO to the MLI-specific driver Pax2-Cre and conduct validation via Kit IHC and immunoblotting. Using this system to examine the functional consequences of presynaptic MLI Kit deletion onto postsynaptic PC cells, they record spontaneous and miniature synaptic currents from PC cells and find a selective reduction in IPSC frequency. Deletion of Kit ligand from postsynaptic PC cells also results in reduced IPSC frequency, together supporting that this trans-synaptic complex regulates GABAergic synaptic formation or maturation. The authors then show that sparse Kit ligand overexpression in PCs decreases neighboring uninfected control sIPSCs in a potentially competitive manner.

      Strengths:<br /> Overall, the study addresses an important open question, the data largely support the authors' conclusions, the experiments appear well-performed, and the manuscript is well-written. I just have a few suggestions to help shore up the author's interpretations and improve the study.

      Weaknesses:<br /> The strong decrease in sIPSC frequency and amplitude in control uninfected cells in Figure 4 is surprising and puzzling. The competition model proposed is one possibility, and I think the authors need to do additional experiments to help support or refute this model. The authors can conduct similar synaptic staining experiments as in Fig S4 but in their sparse infection paradigm, comparing synapses on infected and uninfected cells. Additional electrophysiological parameters in the sparse injection paradigm, such as mIPSCs or evoked IPSCs, would also help support their conclusions.

      The authors should validate KL overexpression and increased cell surface levels using their virus to support their overexpression conclusions.

    1. Reviewer #3 (Public Review):

      This manuscript provides a more or less quantitative analysis of protein synthesis in lymphocytes. I have no issue with the data as presented, as I'm sure all measurements have been expertly done. I see no need for additional experimental work, although it would be helpful if the authors could comment on the possibility of measuring the rate of synthesis of a defined protein, say a histone, in cells prior to and after activation. The conclusion the authors leave us with is the idea that the rates of protein synthesis recorded here are incompatible with observed rates of T cell division in vivo. Indeed, in the final paragraph of the discussion, the authors note the mismatch between what they consider a requirement for cell division, and the observed rates of protein synthesis. They then invoke unconventional mechanisms to make up for the shortfall, without -in this reviewer's opinion- discussing in adequate detail the technical limitations of the methodology used.

      A key question is the broad interest, novelty, and extension of current knowledge, in comparison with Argüello's (reference 27) 'SunRise' method. It would be helpful for the authors to stake out a clear position as to the similarities and differences with reference 27: what have we learned that is new? The authors could cite reference 27 in the introduction of their manuscript, given the similarity in approach. That said, the findings reported here will generate further discussion.

      The manuscript would increase in impact if the authors were to clearly define why a particular measurement is important and then show the actual experiment/result. As an example, it would be helpful to explain to the non-expert why the distinction between monosomes, polysomes, and stalled versions of the same is important, and then explain the rationale of the actual experiment: how can these distinctions be made with confidence, and what are confounding variables? The initial use of human cells, later abandoned in favor of the OT-1 in vitro and in vivo models, requires contextualization. If the goal is to address the relationship between rates of translation and cell division of antigen-activated T cells in vivo, then a lot of the work on the human model and the in vitro experiments becomes more of a distraction, unless properly contextualized. Is there any reason to assume that antigen-specific activation in vivo will impact translation differently than the use of the PMA/ionomycin/IL2 cocktail? The way the work is presented leaves me with the impression that everything that was done is included, regardless of whether it goes to the core of the question(s) of interest.

      It would be helpful if the authors made explicit some of the assumptions that underlie their quantitative comparisons. Likewise, the authors should discuss the limitations of their methods and provide alternative interpretations where possible, even if they consider them less/not plausible, with justification. As they themselves note, improvements in the RPM protocols raised the increase in translating ribosomes upon activation from 10-fold to 15-fold. Who's to say that is the best achievable result? What about the reliability/optimization of the other measurements?

      The composition of the set of proteins produced upon activation will differ from cell to cell (CD4, CD8, B, resting vs. dividing). Even if analyses are performed on fixed cells, the ability of the monoclonal anti-puromycin antibody to penetrate the matrix of the various fixed cell types may not be equal for all of them, depending on protein composition, susceptibility to fixation etc. Is it possible for puromycin to occupy the ribosome's A site and terminate translation without forming a covalent bond with the nascent chain? This could affect the staining with anti-puromycin antibodies and also underestimate the number of nascent chains.

      I believe that the concept of FACS-based quantitation also requires an explanation for the non-expert. For the FACS plots shown, the differences between the highest and lowest RPM scores for cells that divided and that have a similar CFSE score is at least 10-fold. Does that mean that divided cells can differ by that margin in terms of the number of nascent chains present? If I make the assumption that cells stimulated with PMA/ionomycin/IL2 respond more or less synchronously, why would there be a 10-fold difference in absolute fluorescence intensity (anti=puromycin) for randomly chosen cells with similar CFSE values? While the use of MFI values is standard practice in cytofluorimetry, the authors should devote some comments to such variation at the population level.

      It is assumed that for cells to complete division, they must have produced a full and complete copy of their proteome and only then divide. What if cells can proceed to divide even when expressing a subset of the proteome of departure (=the threshold set required for initiation of division), only to complete synthesis of the 'missing ' portion once cell division is complete? Would this obviate the requirement for an unusual mechanism of protein acquisition (trogocytosis; other)?

      Translation is estimated to proceed at a rate of ~6 amino acids per second, but surely there is variability in this number attributable to inaccuracies of the methods used, in addition to biological variability. Were these so-called standard values determined for a range of different tissues? It stands to reason that there might be variation depending on the availability of initiation/elongation factors, NTPs, aminoacyl tRNAs etc. What is the margin of error in calculating chain elongation rates based on the results shown here?

    1. Reviewer #3 (Public Review):

      The authors introduce two new concepts for antimicrobial resistance borrowed from pharmacology, "variant vulnerability" (how susceptible a particular resistance gene variant is across a class of drugs) and "drug applicability" (how useful a particular drug is against multiple allelic variants). They group both terms under an umbrella term "drugability". They demonstrate these features for an important class of antibiotics, the beta-lactams, and allelic variants of TEM-1 beta-lactamase.

      The strength of the result is in its conceptual advance and that the concepts seem to work for beta-lactam resistance. However, I do not necessarily see the advance of lumping both terms under "drugability", as this adds an extra layer of complication in my opinion.

      I also think that the utility of the terms could be more comprehensively demonstrated by using examples across different antibiotic classes and/or resistance genes. For instance, another good model with published data might have been trimethoprim resistance, which arises through point mutations in the folA gene (although, clinical resistance tends to be instead conferred by a suite of horizontally acquired dihydrofolate reductase genes, which are not so closely related as the TEM variants explored here).

      The impact of the work on the field depends on a more comprehensive demonstration of the applicability of these new concepts to other drugs.

    1. Reviewer #3 (Public Review):

      This study performs in vivo recordings of neurons in the mouse superior colliculus and their afferents from the retina, retinal ganglion cells (RGCs). Building on a preparation they previously published, this study adds the use of optogenetic identification of inhibitory neurons (aka optotagging) to compare RGC connectivity to excitatory and inhibitory neurons in SC. Using this approach, the authors characterize connection probability, strength, and response correlation between RGCs and their target neurons in SC, finding several differences from what is observed in the retina-thalamus-visual cortex pathway. As such, this may be a useful dataset for efforts to understand retinocollicular connectivity and computations.

    1. Reviewer #3 (Public Review):

      This manuscript describes the development of CRISPR knockouts for gh, fsh and tsh in the fast-aging Nothobranchius furzeri grz strain. CRISPR knockouts have been published before, and the strength of the paper is that here, the authors include a novel, easy and fast way of rescuing the loss of function in the entire body by electroporation in muscle. This offers flexibility in timing and dosage, and leads to intriguing results regarding the role of these hormones in growth and fertility. Finally they also add a conditional doxycycline-dependent overexpression model that would allow even more control over the modalities of the rescue. The phenotypes of the knockouts were not the key message of the paper and remained at times only superficially described. The doxycycline-dependent overexpression was only minimally validated, and here it is not yet clear how robust this system is in terms of overexpression levels, timing, and reversibility.

      Overall this study brings a new set of tools in the killifish toolbox that can have much wider applications and will be appreciated also in other teleost models.

    1. Reviewer #3 (Public Review):

      The present study used novel data logging devices to record the foraging behavior of wandering albatrosses. Specifically, the authors showed how localized winds and wave heights influence their ability to take off from the sea surface, which is the most expensive behavior they engage in while foraging. There is no better platform for this initial work because these birds are so large, the equipment they can carry without creating significant impact is tremendous.

      The results were impressive, presented well, and the paper was generally written in an accessible way to readers with less knowledge. The authors provide a convincing set of results that support the aims and conclusions. The theory and application could be used to inform our understanding of flight behavior in other seabirds.

      Although the idea of taking off from the sea surface may sound trivial, it is essential to understand that albatrosses and other soaring seabirds have wings that are adapted for soaring (i.e. long and narrow). The trade off, however, is that powered flight through wing flapping is energetically expensive because the wings have a shallow amplitude and generate less power compared to a shorter, wider wing. Thus, wind is everything and this study shows how wind facilitates the ability of the birds to gain flight using wind and waves. Awesome!

    1. Reviewer #3 (Public Review):

      In this work, the authors tried to profile time-dependent changes in gene and protein expression during BMP-induced amnion differentiation from hPSCs. The authors depicted a GATA3 - TFAP2A - ISL1/HAND1 order of amniotic gene activation, which provides a more detailed temporary trajectory of amnion differentiation compared to previous works. As a primary goal of this study, the above temporal gene/protein activation order is amply supported by experimental data. However, the mechanistic insights on amniotic fate decision, as well as the transcriptomic analysis comparing amnion-like cells from this work and other works remain limited. While this work allows us to see more details of amnion differentiation and understand how different transcription factors were turned on in a sequence and might be useful for benchmarking the identity of amnion in ex utero cultured human embryos/embryoids, it provides limited insights on how amnion cells might diverge from primitive streak / mesoderm-like cells, despite some transcriptional similarity they shared, during early development.

    1. Reviewer #3 (Public Review):

      In this manuscript by Berrocal and coworkers, the authors do a deep dive into the transcriptional regulation of the eve gene in both an endogenous and ectopic background. The idea is that by looking at eve expression under non-native conditions, one might infer how enhancers control transcriptional bursting. The main conclusion is that eve enhancers have not evolved to have specific behaviors in the eve stripes, but rather the same rates in the telegraph model are utilized as control rates even under ectopic or 'de novo' conditions. For example, they achieve ectopic expression (outside of the canonical eve stripes) through a BAC construct where the binding sites for the TF Giant are disrupted along with one of the eve enhancers. Perhaps the most general conclusion is that burst duration is largely constant throughout at ~ 1 - 2 min. This conclusion is consistent with work in human cell lines that enhancers mostly control frequency and that burst duration is largely conserved across genes, pointing to an underlying mechanistic basis that has yet to be determined.

    1. Reviewer #3 (Public Review):

      Strengths:

      On the positive side, I thought the use of ChatGPT to score the sentiment of text was novel and interesting, and I was largely convinced by the parts of the methods which illustrate that the AI provides broadly similar sentiment and politeness scores to humans who were asked to rank a sub-set of the reviews. The paper is mostly clear and well-written, and tackles a question of importance and broad interest (i.e. the potential for bias in the peer review process, and the objectivity of peer review).

      Weaknesses:

      The sample size and scope of the paper are a bit limited, and I have concerns covering diverse aspects including statistical/inferential issues, missing references, and suggestions for other material that could be included that would greatly increase the usefulness of the paper. A major limitation is that the paper focuses on published papers, and thus is a biased sample of all the reviews that were written, which prevents the paper properly answering the questions that it sets out to answer (e.g. is peer review repeatable, fair and objective).

    1. Reviewer #3 (Public Review):

      This paper reports a considerable technical achievement: the optogenetic activation of single retinal ganglion cells in vivo in monkeys. As clearly specified in the paper, this is an important step towards causal tests of the role of specific ganglion cell types in visual perception. Yet this methodological advance is not described currently in sufficient detail to replicate or evaluate. The paper could be improved substantially by including additional methodological details. Some specific suggestions follow.

      The start of the results needs a paragraph or more to outline how you got to Figure 1. Figure 1 itself lacks scale bars, and it is unclear, for example, that the ganglion cells targeted are in the foveal slope.

      The text mentions the potential difficulties targeting ganglion cells at larger eccentricities where the soma density increases. If this is something that you have tried it would be nice to include some of that data (whether or not selective activation was possible). Related to this point, it would be helpful to include a summary of the ganglion cell density in monkey retina.

      Related to the point in the previous paragraph - do you have any experiments in which you systematically moved the stimulation spot away from the target ganglion cell to directly test the dependence of stimulation on distance? This would be a valuable addition to the paper.

      The activity in Figure 1 recovers from activation very slowly - much more slowly than the light response of these cells, and much more slowly than the activity elicited in most optogenetic studies. Can you quantify this time course and comment on why it might be so slow?

      Traces from non-targeted cells should be shown in Figure 1 along with those of targeted cells.

    1. Reviewer #3 (Public Review):

      a) Important findings<br /> - This study confirms that Gr28 subfamily members are expressed in distinct sets of taste neurons in Drosophila larvae, supporting previous findings (e.g., Kwon et al., 2011).<br /> - Neurons expressing different members of the Gr28 family exhibit distinct behavioral responses when chemically activated with capsaicin.<br /> - Silencing experiments reveal that neurons expressing Gr28bc are necessary for larval avoidance of four bitter compounds, whereas neurons expressing Gr28be are necessary for avoiding lobeline and caffeine.<br /> - Inserting either Gr28ba or Gr28bc into the GR28 mutant line restored larval avoidance of denatonium.<br /> - Calcium imaging experiments show that Gr28ba and Gr28bc are involved in sensing denatonium, while none of the GR28 family members are involved in detecting quinine.

      b) Caveats<br /> - The authors did not acknowledge that neurons expressing members of the GR28 family also express other Gr family members, which could potentially contribute to the detection and behavioral responses to the tested bitter compounds.<br /> - Gal4 lines from various studies exhibit varying expression patterns, highlighting the necessity for improved reagents. These findings also suggest the importance of employing different Gal4 lines for each receptor to validate the results of the current study.<br /> - Activating or silencing neurons pertains to the function of the neurons rather than the receptors.<br /> - Inconsistency is observed in the use of different reagents across the experiments. Specifically, all six Gal4 lines were utilized in the Chemical Activation experiments, while only two lines were employed in the silencing experiments.<br /> - The Alphafold structure prediction is exciting but lacks conclusive evidence.

    1. Reviewer #3 (Public Review):

      Leeds et al. employ elegant in vitro experiments and sophisticated numerical modeling to investigate the ability of mechanical coupling to coordinate the growth of individual microtubules within microtubule bundles, specifically k-fibers. While individual microtubules naturally polymerize at varying rates, their growth must be tightly regulated to function as a cohesive unit during chromosome segregation. Although this coordination could potentially be achieved biochemically through selective binding of polymerases and depolymerases, the authors demonstrate, using a novel dual laser trap assay, that mechanical coupling alone can also coordinate the growth of in vitro microtubule pairs.

      By reanalyzing recordings of single microtubules growing under constant force (data from their own previous work), the authors investigate the stochastic kinetics of pausing and show that pausing is suppressed by tension. Using a constant shared load, the authors then show that filament growth is tightly coordinated when pairs of microtubules are mechanically coupled by a material with sufficient stiffness. In addition, the authors develop a theoretical model to describe both the natural variability and force dependence of growth, using no freely adjustable parameters. Simulations based on this model, which accounts for stochastic force-dependent pausing and intrinsic variability in microtubule growth rate, fit the dual-trap data well.

      Overall, this study illuminates the potential of mechanical coupling in coordinating microtubule growth and offers a framework for modeling k-fibers under shared loads. The research exhibits meticulous technical rigor and is presented with exceptional clarity. It provides compelling evidence that a minimal, reconstituted biological system can exhibit complex behavior. As it currently stands, the paper is highly informative and valuable to the field.

      To provide further clarity regarding the implications of their study, the authors may wish to address the following points in more detail:

      - Considering the authors' understanding of the quantitative relationship between forces, microtubule growth, and coordination, is the dual trap assay necessary to demonstrate this coordination? What advantages does the (semi)experimental system offer compared to a purely in silico treatment?

      - What are the limitations of studying a system comprising only two individual microtubules? How might the presence of crosslinkers, which are typically present in vivo between microtubules, influence their behavior in this context?

      - How dependent are the results on the chosen segmentation algorithm? Can the distributions of pause and run durations truly be fitted by "simple" Gaussians, as indicated in Figure S5-2? Given the inherent limitations in accurately measuring short durations and the application of threshold durations, it is likely that the first bins in the histograms underestimate events. Cumulative plots could potentially address this issue.

    1. Reviewer #3 (Public Review):

      The authors investigated the initial steps involved in angiogenesis. Using appropriate experimental tools they associated engineered vasculature models with a strong mathematical analysis. The study provides a dynamic view of the early steps involved in angiogenesis. It shows significant fluctuations in the onset of angiogenesis that suggest transitions between order and disorder in cell organization. The data obtained strongly support the hypothesis and support the conclusion of the study. This work brings new insights into the comprehension of the complex processes involved in the onset of angiogenesis and it provides a strong model to predict how VEGF will activate the delta-NOTCH signaling. Nevertheless, it would be important to describe in more detail how the current study can be used for a better understanding of the angiogenesis process in physiological and in pathological situations.

    1. Reviewer #3 (Public Review):

      Prior work from the Kaverina lab and others had determined that beta-cells build a microtubule network that differs from the canonical radial organization typical in most mammalian cell types and that this organization facilitates the regulated secretion of insulin-containing secretory granules (IGs). In this manuscript, the authors tested the hypothesis that kinesin-driven microtubule sliding is an underlying mechanism that establishes a sub-membranous microtubule array that regulates IG secretion. They employed knock-down and dominant-negative strategies to convincingly show microtubule sliding does, in fact, drive the assembly of the sub-membranous microtubule band. They also used live cell imaging assays to demonstrate that kinesin-mediated microtubule sliding in beta-cells is triggered by extracellular high glucose. Overall, this is an interesting and important study that relates microtubule dynamics to an important physiological process. The experiments were rigorous and well-controlled.

    1. Reviewer #3 (Public Review):

      Summary:<br /> Using a combination of approaches, including automated feature selection and hierarchical clustering, the author identified a set of genes persistently associated with extrachromosomal DNA (ecDNA) presence across cancer types. The authors further validated the gene set identified using gene ontology enrichment analysis and identified that upregulated genes in extrachromosomal DNA-containing tumors are enriched in biological processes like DNA damage and cell proliferation, whereas downregulated genes are enriched in immune response processes.

      Major comments:<br /> 1. The authors presented a solid comparative analysis of ecDNA-containing and ecDNA-free tumors. An established automated feature selection approach, Boruta, was used to select differentially expressed genes (DEG) in ecDNA(+) and ecDNA(-) TCGA tumor samples, and the iterative selection process and two-tier multiple hypothesis testing ensured the selection of reliable DEGs. The author showed that the DEG selected using Boruta has stronger predictive power than genes with top log-fold changes.

      2. The author performed a thorough interpretation of the findings with GO enrichment analysis of biological processes enriched in the identified DEG set, and presented interesting findings, including the enrichment in DNA damage process among the genes upregulated in ecDNA(+) tumors.

      3. Overall, the authors achieved their aims with solid data mining and analysis approaches applied to public data tumor data sets.

      4. While it may not be the scope of this study, it will be interesting to at least have some justification for choosing Boruta over other feature selection methods, such as Recursive Feature Elimination (RFE) and backward stepwise selection.

      5. The authors showed that DESEQ-selected DEGs with top log-fold changes have less strong predictive power and speculated that this may be due to the fact that genes with top log-fold changes (LFC) are confined only to a small subset of samples. It will be interesting to select DEGs with top log-fold changes after first partitioning the tumor samples. For example, randomly partition the tumor samples, identify the DEGs with top LFC, combine the DEGs identified from each partition, then evaluate the predictive power of these DEGs against the Boruta-selected DEGs.

      6. While the authors showed that the presence of mutations was not able to classify ecDNA(+) and (-) tumor samples, it will be interesting to see if variant allele frequencies of the genes containing these mutations have predictive power.

    1. Reviewer #3 (Public Review):

      Summary:<br /> Variants in the UBA5 gene are associated with rare developmental and epileptic encephalopathy, DEE44. This research developed a system to assess in vivo and in vitro genotype-phenotype relationships between UBA5 allele series by humanized UBA5 fly models and biochemical activity assays. This study provides a basis for evaluating current and future individuals afflicted with this rare disease.

      Strengths:<br /> The authors developed a method to measure the enzymatic reaction activity of UBA5 mutants over time by applying the UbiReal method, which can monitor each reaction step of ubiquitination in real time using fluorescence polarization. They also classified fruit fly carrying humanized UBA5 variants into groups based on phenotype. They found a correlation between biochemical UBA5 activity and phenotype severity.

      Weaknesses:<br /> In the case of human DEE44, compound heterozygotes with both loss-of-function and hypomorphic forms (e.g., p.Ala371Thr, p.Asp389Gly, p.Asp389Tyr) may cause disease states. The presented models have failed to evaluate such cases.

    1. Reviewer #3 (Public Review):

      The work presented in the manuscript tries to identify tRNA modifications present in Mycobacterium tuberculosis (Mtb) using reverse transcription-derived error signatures with tRNA-seq. The study identified enzyme homologs and correlates them with presence of respective tRNA modifications in Mtb. The study used several chemical treatments (IAA and alkali treatment) to further enhance the reverse transcription signals and confirms the presence of modifications in the bases. tRNA modifications by two enzymes TruB and MnmA were established by doing tRNA-seq of respective deletion mutants. Ultimately, authors show that MnmA-dependent tRNA modification is important for intracellular growth of Mtb. Overall, this report identifies multiple tRNA modifications and discuss their implication in Mtb infection.

    1. Reviewer #3 (Public Review):

      In this study, the authors sought to test the hypothesis that blocking triglyceride storage in adipose tissue by knockout of DGAT1 and DGAT2 in adipocytes would lead to ectopic lipid deposition, lipodystrophy, and impaired glucose homeostasis. Surprisingly, the authors found the opposite result, with DGAT1/2 DKO in adipocytes leading to increased energy expenditure, minimal ectopic lipid deposition, and improved glucose homeostasis with HFD feeding. These metabolic improvements were largely attributed to increased beiging of the white fat and increased brown adipose tissue activity. This study provides an interesting new paradigm whereby impairing fat storage, the major function of adipose tissue, does not lead to severe metabolic disease, but rather improves it. The authors provide a comprehensive assessment of the metabolism of these DKO mice under chow and HFD conditions, which support their claims. The study lacks in mechanistic insight, which would strengthen the study, but does not detract from the authors' major conclusions.

    1. Reviewer #3 (Public Review):

      In this study, Sun et al examine the role of the splicing factor SRSF1 in spermatogenesis in mice. Alternative splicing is important for spermatogenic development, but its regulation and major developmental roles during spermatogenesis are not well understood. The authors set out to better define both SRSF1 function in testes and the contribution of alternative splicing. They collect several large 'omics datasets to define SRSF1 targets in testis, including RNA interactions by CLIP-seq in whole testis, protein interactions by IP-mass spec in whole testis, and RNA sequencing to detect expression levels and splice variants. They also examine the phenotype of germline conditional knockouts (cKO) for Srsf1, using the early-acting Vasa-Cre, and find a severe depletion of germ cells starting at 7 days post partum (dpp) and culminating with a lack of germ cells (Sertoli Cell Only Syndrome) by adulthood. They detect differences in gene expression as well as differences in splicing between control and knockout, including 9 genes that are downregulated, experience alternative splicing, and whose transcripts are also bound by SRSF1, and identify the Tial1/Tiar transcript as one of these targets. They conclude that SRSF1 is required for homing and self-renewal of spermatogonial stem cells, at least in part through its regulation of Tial1/Tiar splicing.

      Strengths of the paper include detailed phenotyping of the Srsf1 cKO, which convincingly supports the Sertoli Cell Only phenotype, establishes the timing of the first appearance of the spermatogonial defect, and provides new insight into the role of splicing factors and SRSF1 specifically in spermatogenesis. Another strength is the generation of CLIP-seq, IP-MS, and RNA-seq datasets which will be a useful resource for the field of germ cell development. Major weaknesses include a lack of robust support for two major claims: first, there is inadequate support for the claim of defects in either "homing" or "self-renewal" of spermatogonia in the cKO, and second, there is inadequate support for the claim that altered splicing of the Tial1 transcript mediates the effect of SRSF1 loss. A moderate weakness is the superficial discussion of the CLIP, RNA-seq, and IP-MS datasets, limiting their otherwise high utility for other researchers. Overall, the paper as it stands will have a moderate impact on the field of male reproductive biology. Specific points that should be addressed to improve support for the claims are below.

      Major comments

      1) In Fig 1D, it appears that SRSF1 is expressed most strongly in spermatogonia by immunofluorescence, but this is inconsistent with the sharp rise in expression detected by RT-qPCR at 20 days post partum (dpp) (Fig. 1B), which is when round spermatids are first added; this discrepancy should be explained or addressed.

      2) It is important to provide a more comprehensive basic description of the CLIP-seq datasets beyond what is shown in the tracks shown in Fig. 2B. This would allow a better assessment of the data quality and would also provide information about the transcriptome-wide patterns of SRSF1 binding. No information or quality metrics are provided about the libraries, and it is not stated how replicates are handled to maximize the robustness of the analysis. The distribution of peaks across exons, introns, and other genomic elements should also be shown.

      3) The claim that SRSF1 is required for "homing and self-renewal" of SSCs is made in multiple places in the manuscript. However, neither homing nor self-renewal is ever directly tested. A single image is shown in Fig. 5E of a spermatogonium at 5dpp that does not appropriately sit on the basal membrane, potentially indicating a homing defect, but this is not quantified or followed up. There is good evidence for depletion of spermatogonia starting at 7 dpp, but no further explanation of how homing and/or self-renewal fit into the phenotype.

      4) In Fig. 6A (lines 258-260) very few genes downregulated in the cKO are bound by SRSF1 and undergo abnormal splicing. The small handful that falls into this overlap could simply be noise. A much larger fraction of differentially spliced genes are CLIP-seq targets (~33%), which is potentially interesting, but this set of genes is not explored.

      5) The background gene set for Gene Ontology analyses is not specified. If these were done with the whole transcriptome as background, one would expect enrichment of spermatogenesis genes simply because they are expressed in testes. The more appropriate set of genes to use as background in these analyses is the total set of genes that are expressed in testis.

      6) In general, the model is over-claimed: aside from interactions by IP-MS, little is demonstrated in this study about how SRSF1 affects alternative splicing in spermatogenesis, or how alternative splicing of TIAL1 specifically would result in the phenotype shown. It is not clear why Tial1/Tiar is selected as a candidate mediator of SRSF1 function from among the nine genes that are downregulated in the cKO, are bound by SRSF1, and undergo abnormal splicing. Although TIAL1 levels are reduced in cKO testes by Western blot (Fig. 7J), this could be due just be due to a depletion of germ cells from whole testis. The reported splicing difference for Tial1 seems very subtle and the ratio of isoforms does not look different in the Western blot image.

    1. Reviewer #3 (Public Review):<br /> <br /> Tutor et al. present their work on Kelch13/K13 from Plasmodium falciparum, the causative agent of malaria. This protein is involved in resistance against artemisinin (ART), one of the most commonly used drugs to treat malaria. Despite having identified the mutation in K13 that leads to resistance to ART, the exact molecular mechanism, function of K13, and impact of the K13 mutations still need to be elucidated. This is where the authors step in to investigate the relationship between endocytosis and K13, as well as the impact of depleting the protein using knock-sideway (KS). Using light microscopy, the authors demonstrate how K13-YFP forms a pore associated with fluorescently labeled dextran, which is taken up into tubules that move toward the digestive vacuole. This tubule formation is not sensitive to jasplakinolide (JAS) treatment. Using electron microscopy, they show that K13 is localized at the dark contrast border of the cytostome, and knocking down K13 leads to the disruption of the cytostome structure. Upon removal of K13, the structure changes, and the opening enlarges. The impact of KS induction on the cytostome was quantified using TEM and tomography. The authors also provide reconstructions of the cytostome in both induced and non-induced parasites. Finally, they measure the impact of KS on haem degradation. These data provide clear information on the function of K13 in cytostome formation and the implication of this structure in endocytosis for Plasmodium falciparum.

      The conclusions of this paper are well supported by the data, but some data analysis should be clarified and extended, and some complementary experiments would further strengthen the authors' claims.

    1. Reviewer #3 (Public Review):

      The authors report a study in which they use intracranial recordings to dissociate subjectively aware and subjectively unaware stimuli, focusing mainly on prefrontal cortex. Although this paper reports some interesting findings (the videos are very nice and informative!) the interpretation of the data is unfortunately problematic for several reasons. I will detail my main comments below. If the authors address these comments well, I believe the paper may provide an interesting contribution to further specifying the neural mechanisms important for conscious access (in line with Gaillard et al., Plos Biology 2009).

      The main problem with the interpretation of the data is that the authors have NOT used a so-called "no-report paradigm". The idea of no report paradigms is that subjects passively view a certain stimulus without the instruction to "do something with it", e.g., detect the stimulus, immediately or later in time. Because of the confusion of this term, specifically being related to the "act of reporting", some have argued we should use the term no-cognition paradigm instead (Block, TiCS, 2019, see also Pitts et al., Phil Trans B 2018). The crucial aspect is that, in these types of paradigms, the critical stimulus should be task-irrelevant and thus not be associated with any task (immediately or later). Because in this experiment subjects were instructed to detect the gratings when cued 600 ms later in time, the stimuli are task relevant, they have to be reported about later and therefore trigger all kinds of (known and potentially unknown) cognitive processes at the moment the stimuli are detected in real-time (so stimulus-locked). You could argue that the setup of this delayed response task excludes some very specific report related processes (e.g., the preparation of an eye-movement), which is good, however this is usually not considered the main issue. For example when comparing masked versus unmasked stimuli (Gaillard et al., 2009 Plos Biology), these conditions usually also both contain responses but these response related processes are "averaged out" in the specific contrasts (unmasked > masked). In this paper, RT differences between conditions (that are present in this dataset) are taken care of by using this delayed response in this paper, which is a nice feature for that and is not the case for the above example set-up.

      Given the task instructions, and this being merely a delayed-response task, it is to be expected that prefrontal cortex shows stronger activity for subjectively aware versus subjectively unaware stimuli. Unfortunately, given the nature of this task, the novelty of the findings is severely reduced. The authors cannot claim that prefrontal cortex is associated with "visual awareness", or what people have called phenomenal consciousness (this is the goal of using no-cognition paradigms). The only conclusion that can be drawn is that prefrontal cortex activity is associated with accessing sensory input: and hence conscious access. This less novel observation has been shown many times before and there is also little disagreement about this issue between different theories of consciousness (e.g., global workspace theory and local recurrency theories both agree on this).

      The best solution at this point seems to rewrite the paper entirely in light of this. My advice would be to state in the introduction that the authors investigate conscious access using iEEG and then not refer too much to no-cognition paradigm or maybe highlight some different strategies about using task-irrelevant stimuli (see Canales-Johnson et al., Plos Biology 2023; Hesse et al., eLife 2020; Hatamimajoumerd et al Curr Bio 2022; Alilovic et al., Plos Biology 2023; Pitts et al., Frontiers 2014; Dwarakanth et al., Neuron 2023 and more). Obviously, the authors should then also not claim that their results solve debates about theories regarding visual awareness (in the "no-cognition" sense, or phenomenal consciousness), for example in relation to the debate about the "front or the back of the brain", because the data do not inform that discussion. Basically, the authors can just discuss their results in detail (related to timing, frequency, synchronization etc) and relate the different signatures that they have observed to conscious access.

      I think the authors have to discuss the Gaillard et al PLOS Biology 2009 paper in much more detail. Gaillard et al also report a study related to conscious access contrasting unmasked and masked stimuli using iEEG. In this paper they also report ERP, time frequency and phase synchronization results (and even Granger causality). Because of the similarities in approach, I think it would be important to directly compare the results presented in that paper with results presented here and highlight the commonalities and discrepancies in the Discussion.

      In the Gaillard paper they report a figure plotting the percentage of significant frontal electrodes across time (figure 4A) in which it can be seen that significant electrodes emerge after approximately 250 ms in PFC as well. It would be great if the authors could make a similar figure to compare results. In the current paper there are much more frontal electrode contacts than in the Gaillard paper, so that is interesting in itself.

      In my opinion, some of the most interesting results are not highlighted: the findings that subjectively unaware stimuli show increased activations in the prefrontal cortex as compared to stimulus absent trials (e.g., Figure 4D). Previous work has shown PFC activations to masked stimuli (e.g., van Gaal et al., J Neuroscience 2008, 2010; Lau and Passigngham J Neurosci 2007) as well as PFC activations to subjectively unaware stimuli (e.g., King, Pescetelli, and Dehaene, Neuron 2016) and this is a very nice illustration of that with methods having more detailed spatial precision. Although potentially interesting, I wonder about the objective detection performance of the stimuli in this task. So please report objective detection performance for the patients and the healthy subjects, using signal detection theoretic d'. This gives the reader an idea of how good subjects were in detecting the presence/absence of the gratings. Likely, this reveals far above chance detection performance and in that case I would interpret these findings as "PFC activation to stimuli indicated as subjectively unaware" and not unconscious stimuli. See Stein et al., Plos Biology 2021 for a direct comparison of subjectively and objectively unaware stimuli.

      In Figure 7 of the paper the authors want to make the case that the contrast does not differ between subjectively aware stimuli and subjectively unaware stimuli. However so far they've done the majority of their analyses across subjects, and for this analysis the authors only performed within-subject tests, which is not a fair comparison imo. Because several P values are very close to significance I anticipate that a test across subjects will clearly show that the contrast level of the subjectively aware stimuli is higher than of the subjectively unaware stimuli, at the group level. A solution to this would be to subselect trials from one condition (NA) to match the contrast of the other condition (NU), and thereby create two conditions that are matched in contrast levels of the stimuli included. Then do all the analyses on the matched conditions.

      Related, Figure 7B is confusing and the results are puzzling. Why is there such a strong below chance decoding on the diagonal? (also even before stimulus onset) Please clarify the goal and approach of this analysis and also discuss/explain better what they mean.

      I was somewhat surprised by several statements in the paper and it felt that the authors may not be aware of several intricacies in the field of consciousness. For example a statement like the following "Consciousness, as a high-level cognitive function of the brain, should have some similar effects as other cognitive functions on behavior (for example, saccadic reaction time). With this question in mind, we carefully searched the literature about the relationship between consciousness and behavior; surprisingly, we failed to find any relevant literature." This is rather problematic for at least two reasons. First, not everyone would agree that consciousness is a high-level cognitive function and second there are many papers arguing for a certain relationship between consciousness and behavior (Dehaene and Naccache, 2001 Cognition; van Gaal et al., 2012, Frontiers in Neuroscience; Block 1995, BBS; Lamme, Frontiers in Psychology, 2020; Seth, 2008 and many more). Further, the explanation for the reaction time differences in this specific case is likely related to the fact that subjects' confidence in that decision is much higher in the aware trials than in the unaware trials, hence the speeded response for the first. This is a phenomenon that is often observed if one explores the "confidence literature". Although the authors have not measured confidence I would not make too much out of this RT difference.

      I would be interested in a lateralized analysis, in which the authors compare the PFC responses and connectivity profiles using PLV as a factor of stimulus location (thus comparing electrodes contralateral to the presented stimulus and electrodes ipsilateral to the presented stimulus). If possible this may give interesting insights in the mechanism of global ignition (global broadcasting), supposing that for contralateral electrodes information does not have to cross from one hemisphere to another, whereas for ipsilateral electrodes that is the case (which may take time). Gaillard et al refer to this issue as well in their paper, and this issue is sometimes discussed regarding to Global workspace theory. This would add novelty to the findings of the paper in my opinion.

    1. Reviewer #3 (Public Review):

      The authors report on the nature of interventions that were applied to aid and improve engagement in cervical screening, brought about by the SARS CoV Pandemic in Sweden.

      I appreciate that the impact of these interventions, given that they are recent, will take some time to quantify but the description (and reach) of the policy changes that occurred in a short amount of time is of significant interest to the screening community. The piece on HPV Even Faster is particularly novel; I am not aware of another example of where this has been enacted within a routine programme.

      The authors make reference to (15) where the reader can find greater details relating to the population who received the offer of self sampling (and the nature of the device). However I was a little confused (in this stand alone piece) as to who the self sampling group constituted exactly. Did this group not include pregnant women, women invited for first screen or women on non routine recall?

      The authors state that "the most likely explanation for the large increase in population coverage seen is that the sending of self-sampling kits resulted in improved attendance in particular among previously non-attending women" - why is this written as speculation at this stage (?) is it not possible to attribute directly the contribution made by self sampling, or is this in hand?

      While self sampling is certainly an option that can support uptake and enfranchisement in cervical screening - its overall performance is fundamentally contingent on the number of women who then comply with follow up should the HPV test be positive; it is not simply about who returns the sample. It would have been of interest to see the proportion of women who did comply with follow up.

    1. Reviewer #3 (Public Review):

      'Collateral sensitivity' occurs when drug-resistance mutations render a drug target more sensitive to inhibition by another drug, which has been previously described in some detail for malaria parasite dihydroorotate dehydrogenase (DHODH - see refs 36, 46, and 47, for example). Although it has been suggested that combinations of such drugs could potentially suppress the emergence of resistance, cross-resistance-associated mutation (or copy-number variation, CNV) could render such combination strategies ineffective. In the current study, the authors assess a new pairing of DHODH-targeting drugs. Cross-resistant parasites with DHODH mutation or CNV arise following either sequential or combined drug selection, suggesting that the drug combination described would likely fail to effectively suppress the emergence of resistance.

      The strength of the study is that it describes, for a particular drug combination, different mutations associated either with collateral sensitivity or with cross-resistance, and the authors conclude that "combination treatment with DSM265 and TCMDC-125334 failed to suppress resistance". They go on to say that this "brings into question the usefulness of pursuing further DHODH inhibitors." More specific interpretations and implications of the study are as follows:<br /> a. Other combinations may also fail but there may be combinations that can effectively suppress resistance. A more exhaustive analysis of mutational space will likely be required to determine which combinations if any, would be predicted to succeed in a clinical setting.<br /> b. It was previously reported that "a combination of [DHODH] wild-type and mutant-type selective inhibitors led to resistance far less often than either drug alone. ... Comparative growth assays demonstrated that two mutant parasites grew less robustly than their wild-type parent, and the purified protein of those mutants showed a decrease in catalytic efficiency, thereby suggesting a reason for the diminished growth rate" (Ref 46). Also, "selection with a combination of Genz-669178, a wild-type PfDHODH inhibitor, and IDI-6273, a mutant-selective PfDHODH inhibitor, did not yield resistant parasites" (Ref 36). It is possible that these previously tested combinations would also yield cross-resistant mutants if selected further.<br /> c. Although increased DHODH copy number "confers only moderately reduced susceptibility" to the drug used for selection and although these clones were not assessed here for cross-resistance, it seems likely that CNV may represent a general mechanism that could undermine other collateral resistance strategies.

    1. Reviewer #3 (Public Review):

      The authors described their extensive single-cell analysis of Candida undergoing (sub-inhibitory) antibiotic treatment versus no treatment. To do so, the authors used a microfluidics platform they had previously developed, and they optimized, characterized, and validated it for this particular application. Their findings included: (a) the transcription of untreated cells is driven mostly by cell cycle phase, (b) treated cells can be clustered into several major groups and a few outlier groups that the authors termed comets, (c) cells undergoing FCZ treatment can adopt one of two different states (possibly bistability). I found the results interesting and the approach to be sound, and much of the results confirmed my prior expectations. The authors provide a detailed depiction of what is going on in the transcriptome during sub-inhibitory treatment, although this did not always lead to a mechanistic explanation. The clinical relevance was unclear to me beyond a proof of concept application for single-cell transcriptomics. In my opinion, an interesting follow-up would be to follow the transcriptional trajectory of lineages undergoing antimicrobial switching (on and off). The main issues I identified were the author's use of the term tolerance versus resistance, interpretation of "comets", clustering approach, description of fitness, and comparison between time points.

    1. Reviewer #3 (Public Review):

      Increased LRRK2 kinase activity is known to confer Parkinson's disease risk. While much is known about disease-causing LRRK2 mutations that increase LRRK2 kinase activity, the normal cellular mechanisms of LRRK2 activation are less well understood. Rab GTPases are known to play a role in LRRK2 activation and to be substrates for the kinase activity of LRRK2. However, much of the data on Rabs in LRRK2 activation comes from over-expression studies and the contributions of endogenously expressed Rabs to LRRK2 activation are less clear. To address this problem, Bondar and colleagues tested the impact of systematically depleting candidate Rab GTPases on LRRK2 activity as measured by its ability to phosphorylate Rab10 in the human A549 type 2 pneumocyte cell line. This resulted in the identification of a major role for Rab12 in controlling LRRK2 activity towards Rab10 in this model system. Follow-up studies show that this role for Rab12 is of particular importance for the phosphorylation of Rab10 by LRRK2 at damaged lysosomes. Increases in LRRK2 activity in cells harboring disease-causing mutants of LRRK2 and VPS35 also depend (at least partially) on Rab12. Confidence in the role of Rab12 in supporting LRRK2 activity is strengthened by parallel experiments showing that either siRNA-mediated depletion of Rab12 or CRISPR-mediated Rab12 KO both have similar effects on LRRK2 activity. Collectively, these results demonstrate a novel role for Rab12 in supporting LRRK2 activation in A549 cells. It is likely that this effect is generalizable to other cell types. However, this remains to be established. It is also likely that lysosomes are the subcellular site where Rab12-dependent activation of LRRK2 occurs. Independent validation of these conclusions with additional experiments would strengthen this conclusion and help to address some concerns that much of the data supporting a lysosome localization for Rab12-dependent activation of LRRK2 comes from a single method (LysoIP). Furthermore, there is a discrepancy between panel 4A versus 4D in the effect of LLoMe-induced lysosome damage on LRRK2 recruitment to lysosomes that will need to be addressed to strengthen confidence in conclusions about lysosomes as sites of LRRK2 activation by Rab12.

    1. Reviewer #3 (Public Review):

      This manuscript by Bellegarda et al. examined the in vivo dynamic behavior of the Reissner fiber and its interactions with cilia and sensory neurons in the central canal of zebrafish larvae. The authors accomplished this by performing live imaging with a transgenic reporter zebrafish line in which the fiber is GFP-tagged and by finely tracking the movement of the fiber. Interestingly, they discovered that the fiber undergoes a dynamic vibratory-like movement along the dorsoventral axis. The authors then utilized a pulsed laser to precisely cut the fiber, which frequently resulted in a fast retraction behavior and a loss of calcium activity in sensory neurons in the central canal called CSF-CNs. Mechanical modeling of the elastic properties of the fiber indicated that the fiber is a soft elastic rod with graded tension along the rostrocaudal axis. Finally, by performing live imaging of motile cilia and the fiber in the central canal, they found that the two interact in close proximity and that cilia motility is affected when the fiber was cut. The authors concluded that the Reissner fiber is a dynamic structure under tension that interacts with sensory neurons and cilia in the central canal.

      Strengths:<br /> 1. The study utilizes state-of-the-art microscopy techniques and beautiful transgenic zebrafish tools to characterize the in vivo behavior of the Reissner fiber and found that it exhibits surprising dynamic movements along the dorsal-ventral axis. This observation has important implications for the physiology and function of the Reissner fiber.

      2. By performing a series of clever laser cutting experiments, the authors reveal that the Reissner fiber is under tension in the central canal of zebrafish. This finding provides direct experimental evidence to support the hypothesis that the Reissner fiber functions in a biomechanical manner during spinal cord development and body axis straightening.

      3. By developing a mechanical model of the Reissner fiber and its retraction behavior, the authors estimate the elastic properties of the fiber and found that it is more akin to an elastic polymer rather than a stiff rod. This is a useful finding that illuminates the biophysical properties of the fiber.

      4. Through calcium and cilia imaging studies, the authors demonstrate that the Reissner fiber likely interacts with motile cilia and regulates the activity of ciliated sensory neurons (CSF-CNs). The authors propose a model in which fiber-cilia interactions may occur via weak interactions or frictional forces. This model is plausible and opens several new doors for additional investigation.

      Weaknesses:<br /> 1. All the live imaging experiments appear to be performed with animals paralyzed via the injection of a chemical agent (bungarotoxin). Does paralysis and/or bungarotoxin negatively impact the behavior of the Reissner fiber? Some data from non-paralyzed animals would ameliorate this concern.

      2. Although the authors convincingly demonstrate that the Reissner fiber is under graded tension, it remains unclear what is the relevance and function of tension on this structure. The photoablation data presented do not delineate between the relevance of the fiber being intact or tension on the fiber as cutting the fiber impacts both. Is fiber tension required for body straightening? At the site of fiber photoablation, does a spinal curvature develop? If cultured, do the ablated animals exhibit a scoliotic phenotype?

      3. One of the most potentially impactful conclusions of the paper is that the Reissner fiber interacts with cilia, but the evidence is insufficient to support this. Although some motile cilia are near the fiber (Figure 3A), many cilia are not near the fiber. The provided images and videos do not clearly demonstrate that cilia physically contact or influence the behavior of the Reissner fiber. Further, the data is lacking to conclude that the Reissner fiber directly impacts cilia motility as they did not observe an overall statistically significant difference before and after ablation (Supplemental Figure 1A). Higher magnification, higher resolution, higher acquisition rate and/or colocalization analyses of fiber-cilia interactions could alleviate this concern.

      4. Similarly, how does the Reissner fiber interact with CSF-CN sensory neurons? The authors suggest that the fiber interacts with CSF-CN sensory neurons by modulating their spontaneous calcium activity via weak interactions or frictional forces from motile ciliated ependymal radial glial cells. While the calcium imaging data of the CSF-CNs is convincing and sound, the exact nature of the fiber-neuron interaction is unclear. Do cilia or apical extensions on CSF-CN sensory neurons sense the fiber or forces through a mechanosensing or chemosensing mechanism? There is some additional confusion as the authors appear to focus their cilia experiments on ependymal radial glial cells in section 4, rather than CSF-CNs. The addition of an illustrative cartoon would add clarity.

      Overall, the conclusions of the study are well supported by the data presented. However, the strength of the conclusions could be enhanced by additional controls, alternative experimental approaches and clarifications.

      This manuscript is an important contribution to the fields of spinal cord development and body axis development, which are fundamental questions in neurobiology, developmental biology, and musculoskeletal biology. In recent years, the Reissner fiber and motile cilia function have been linked to cerebrospinal fluid flow signaling and body straightening, but the precise form and function of the fiber remain unclear. This study provides new insight into the dynamic and biophysical properties of the Reissner fiber in vivo in zebrafish and proposes a model in which the fiber interacts with cilia and sensory neurons. This study provides novel insight into the cellular mechanisms that underlie the pathogenesis of disorders such as idiopathic scoliosis.

    1. Reviewer #3 (Public Review):

      CaMKII is a multimeric kinase of great biologic interest due to its crucial roles in long-term memory, cardiac pacemaking, and fertilization. CaMKII subunits organize into holoenzymes comprised of 12-14 subunits, adopting a donut-like, double-ringed structure. In this manuscript, Lucic et al challenge two models in the CaMKII field, which are somewhat related. The first is a longstanding topic in the field about whether the autophosphorylation of a crucial residue, Thr286, can be phosphorylated between intact holoenzymes (inter-holoenzyme phosphorylation). The second is a more recent biochemical finding, which tested the long-running theory that CaMKII exchanges subunits between holoenzymes to create mixed oligomers. These two models are connected by the idea that subunit exchange could facilitate phosphorylation between subunits of different holoenzymes by allowing subunits to integrate into a different holoenzyme and driving transphosphorylation within the CaMKII ring. Here, the authors attempt to show that one intact holoenzyme phosphorylates another intact holoenzyme at Thr286. The authors also provide evidence suggesting that subunit exchange is not occurring under their conditions, and therefore not driving this phosphorylation event. The authors propose a model where instead of exchanging subunits, two holoenzymes interact via their kinase domains to enable transphosphorylation at Thr286 without integrating into the holoenzyme structure. In order for the authors to successfully convince readers of all three facets of this new model, they need to provide evidence that 1) transphosphorylation at Thr286 happens when subunit exchange is blocked, 2) subunit exchange does not occur under their conditions, and 3) there are interactions between kinases of different holoenzymes that lead to productive autophosphorylation at Thr286.

      Strengths:<br /> The authors have designed and performed a battery of cleverly designed and orthogonal experiments to test these models. Using mutagenesis, they mixed a kinase-dead mutant with an active kinase to ask whether transphosphorylation occurs. They observe phosphorylation of the kinase-dead variant in this experiment, which indicates that the active kinase must have phosphorylated it. A few key questions arise here: 1) whether this phosphorylation occurred within a single CaMKII holoenzyme ring (which is the canonical mechanism for Thr286 phosphorylation), 2) whether the phosphorylation occurred between two separate holoenzyme rings, and 3) why was this not observed in previous literature? To address questions 1 and 2, the authors implemented an innovative strategy introducing a genetically-encoded photocrosslinker in the oligomerization domain, which when crosslinked using UV light, should lock the holoenzyme in place. The rate of phosphorylation was the same when comparing uncrosslinked and crosslinked CaMKII variants, indicating that phosphorylation is occurring between holoenzymes, rather than through a subunit exchange mechanism that would require some type of disassembly and reassembly (presumably blocked by crosslinking). The 3rd question remains as to why this has not been previously observed, as it has not been for lack of effort. The authors mention low temperature and low concentration as culprits, however, Bradshaw et al, JBC v. 277, 2002 carry out a series of careful experiments that indicated that autophosphorylation at T286 is not concentration-dependent (meaning that the majority of phosphorylation occurs via intra-holoenzyme), and this is done over a concentration and temperature range. It is possible that due to the mutants used in the current manuscript, it allows for the different behavior of the kinase-dead domains, which will have an empty nucleotide-binding pocket. Further studies will need to elucidate these details, and importantly, understand what physiological conditions facilitate this mechanism.

      The most convincing data that subunit exchange does not occur is from the crosslinking mass spectrometry experiment. The authors created mixtures of 'light' and 'heavy' CaMKII holoenzymes, either activated or not and then used a Lys-Lys crosslinker (DSS) to trap the enzyme in its final state. The results of this experiment indicate that subunit exchange is not occurring under their conditions. A caveat here is that there are not many lysines at hub-hub interfaces, which is the crux of this experiment. If there is no subunit exchange under their conditions, how does transphosphorylation occur between holoenzymes? The authors show very nice mass photometry data indicating that there are populations of 24-mers, which corresponds to a double-holoenzyme. Paired with the data from their crosslinking mass spectrometry which shows crosslinks between kinase domains of different holoenzymes, this indicates that perhaps kinases between holoenzymes do interact, and they do so in a competent manner to allow transphosphorylation to occur.

      Weaknesses:<br /> The authors should be commended for performing three orthogonal experiments to test whether CaMKII holoenzymes exchange subunits to form heterooligomers. However, there are technical issues that dampen the strength of the results shown here. For simplicity, let's consider that CaMKII holoenzymes are comprised of two stacked hexameric rings. It has been proposed that the stable unit of CaMKII assembly and perhaps also disassembly and subunit exchange is a vertical dimer unit (comprised of one subunit from each hexameric ring). In the UV crosslinking data shown in this paper, the authors have a significant number of monomers, some crosslinked dimers (of which there are two populations), and fewer higher-order oligomers. To effectively block subunit exchange, robust crosslinking into hexamers is necessary, which the authors have not done. Incomplete crosslinking results in smaller species that can still exchange (and/or dissociate), confounding the results of this experiment. In addition, Figure 3 shows a trapping experiment, where if the exchange was occurring, there would be an oligomeric band in Lane 8, which is visible and highlighted with a blue arrow by the authors. This result is explained by nonspecific UV effects, however by eye it is not clear if there is an equivalent band in lane 10. The overall issue here is inefficient crosslinking.

      The authors also employ a single-molecule TIRF experiment to further interrogate subunit exchange. Upon inspection of the TIRF images, it is not clear that the authors are achieving single molecule resolution (there are evident overlapping and distorted particles). The analysis employed here is Pearson's correlation coefficient, which is not sufficient for single molecule analysis and would not account for particle overlap, particles that are too bright, and/or particles that are too dim. For example, an alternative explanation for the authors' results is that activation results in aggregation (high correlation), and subsequent EGTA treatment leads to dissociation at these low concentrations (low correlation). However, further experimentation and analysis are necessary.

      Taken together, the authors have provided important food for thought regarding inter-holoenzyme phosphorylation and subunit exchange. However, given the shortcomings discussed here, it remains unclear exactly what mechanisms are at play within and between CaMKII holoenzymes once activated.

    1. Reviewer #3 (Public Review):

      Joechner and their co-authors performed an extensive analysis of two existing datasets from sleeping children aged between 5 to 18 years. By identifying discrete events of slow oscillations (SOs) and (fast) sleep spindles they examined not only the developmental changes of these distinct sleep grapho-elements. They also took a closer look at their interplay, e.g., to what extend sleep spindles are co-occurring with slow oscillation up-states, as this coupling is thought to underlie sleep-dependent memory consolidation.

      The authors found that both sleep spindles and slow oscillation undergo a change across the young age, e.g., while sleep spindles increased in frequency approaching the typical 12-16 Hz range found in adults, slow oscillation showed a shift in occurrence patterns from posterior to anterior sites. Likewise, the coupling of fast spindles within slow oscillation up-states manifested with age, which is almost non-existing in 5- to 6-year-old children. However, and most intriguingly, a coupling analysis based on the adult-like 12-16 Hz range revealed an already existing SO-spindle phase-relation across all age ranges. Altogether, this data nicely demonstrates the trajectory of sleep spindles and SOs in children and highlights the almost inherent coupling between SOs and "adult" sleep spindles. In my view, these results not only provide a good overview of a healthy development but also interesting food for thought regarding the function of SO-spindle coupling in healthy or clinical development.

      Overall, this work is well-written, and the performed analyses are well conceptualized. Hence, there are one general and a few minor aspects that could be addressed to hopefully strengthen this manuscript a bit further.

      The biggest aspect that was striking is the shear amount of data reported, e.g., a supplement with 28 tables is too extensive. The authors should consider reducing a few aspects.<br /> For example, the authors employ a linear mixed effects model and report coefficient etc. in the supplement. However, in the main text, the authors mainly report ANOVA-based results. Obviously, a LMM and an ANOVA are equivalent, however, focusing on one approach could streamline everything.<br /> Another example is the assessment of spindle frequency via the discrete events: First spindle peak frequency is derived via power spectra. Using the then individually identified peaks, discrete events are detected. Shouldn't it be obvious that these events show the same behavior with regard to their frequency?<br /> As a final example, the authors first report changes in fast spindle properties across age and, e.g., find an increase in frequency towards 12-16 Hz adult range. They then repeat the whole analysis in the 12-16 Hz range and examine the "distance" to the individualized results. It should again be obvious that this approach comes to the same conclusion, a smaller distance in older children. Even more obvious is the conclusion "Hence, it appears as if fast centro-parietal SPs become more dominant and adult-like in their frequency and amplitude characteristics in older children" because it describes a normal development of a healthy child. Altogether, the authors could streamline a few aspects by removing hidden redundancies and focus on the - in my view - central aspect of an inherent 12-16 Hz coupling across all ages.

    1. Reviewer #3 (Public Review):

      Mesenchymal stem cells have been shown to have potent immunomodulatory and regenerative properties and have been tested and tried in kidney transplantation. In a previous paper, the authors of this paper reviewed the beneficial actions of nitric oxide (NO) on the beneficial action of MSC. In this manuscript, they describe a method to generate NO in the therapeutic MSC. While NO donors like the short-acting nitrates have been used for angina pectoris patients few therapeutic approaches have been published aiming at the local delivery of NO to specific tissues or organs like the kidney. Gene therapy with adenoviral vectors, overexpressing the eNOS gene itself failed due to the fact that the eNOS enzyme, when overexpressed quickly runs out of sufficient co-factors like BH4. As a consequence, the enzyme uncouples and becomes cytotoxic due to the generation of peroxynitrate. Hence, the current strategy to generate NO in the MSC itself is novel and interesting.

      The authors first describe the cryoprotective effects and antioxidant effects of NO generation in MSC in vitro and subsequently in vivo in a mouse model of ischemia-reperfusion injury that may reflect acute kidney injury (or ischemia associated with kidney transplantation) in patients. While the MSC are transplanted intracortical on a local position in the kidneys, the manuscript describes surprising effectivity on serum creatinine, ureum, casts, and protection of brush border. Also, upon immunohistochemical analyses, fibrosis, and kidney injury markers decrease. Most likely there is a strong paracrine effect. It is unfortunate that the control "PBS + MGP" is lacking to exclude some low-grade background conversion of the compound with subsequent release of NO. MGP only is tested however, studies in kidney sections with state-of-the-art EPR, give the authors the wanted control.

      The paper provides an interesting proof of concept for a novel therapeutic approach. However, in the clinical arena, some questions remain involving the survival of the MSC after transplantation and the introduction of novel antigens associated with the engineered cells

    1. Reviewer #3 (Public Review):

      Pinatel and colleagues addressed a currently understudied topic in neurobiology, namely, the architecture and function of myelination in subsets of Parvalbumin (PV)- and Somatostatin (SST)-positive GABAergic hippocampal interneurons and its dependence on juxtaparanodal organizer proteins. In order to elucidate the structural and functional implications of interneuron myelination, the authors visualized inhibitory neurons by utilizing a Lhx2-tdTomato reporter line in combination with crucial cytoskeletal linker proteins such as Contactin2/TAG-1, Caspr2, and Protein 4.1B. They then applied a comprehensive set of histological, electrophysiological, and behavioral experiments to dissect the role these proteins play in proper myelination and function of PV- and SST-interneurons.

      The bulk of the study's data is based on immunofluorescence, which is presented in a number of figures comprised of high-quality images. As much as this is a strength of the study, the underlying image analysis as described in the methods falls short. All structural data rely on the measurements of physical parameters such as length of internodes, the distance between (juxta)paranode and node, the distance between node and myelin sheath, length of the axon initial segment (AIS), etc. In light of this, and considering the small physical dimensions of the nodal region in general, the methods remain unclear about the depth of 3D reconstruction/deconvolution applied to the samples. Measurements presented in the results show significant differences in sub-micrometer dimension, which at least according to the stated methods, are unlikely to be precise given that the confocal imaging parameters do not seem to reach Nyquist conditions. For a study in which a third of all data is aimed at elucidating (sub)micrometer changes, this is crucial and the study would benefit from a more rigorous method description by the authors.

      Another methodological weakness is the somewhat small n, and its incoherence across the experiments and therefore, the statistics performed in some of the experiments. Statistics are based on either n for animals, or n for individual data points from several animals. Why is not all data represented as mean/animal? Also, the sampling in general with n = 3 animals is borderline acceptable; in some cases, it seems that only 2 animals were used, and in others, no number is given at all (please refer to author comments for details). This needs to be addressed, either by explaining why so few animals were used, or by adding more data from individual animals. Assigning structures (AIS, nodes) as n results in overstating effects, since especially for AIS, there is significant heterogeneity in the length across neurons from the same type, and this is masked when 100 AIS are considered as individual n instead 100 AIS per animal, and the animal is (correctly) the n. Since the study seems to switch back and forth between these assignments, it would be helpful to level these data across all experiments unless there are specific reasons not to do so, which then need to be explained. As outlined in the methods, all values are given as means {plus minus} SEM; this needs to be corrected for those cases where the standard deviation is the appropriate choice (e.g. all graphs showing n = individual structure, and not the mean of an animal).

      As far as the analysis of geometrical AIS changes is concerned, the method section should be extended to address how, if at all, AIS length and position were analyzed in 3D, also considering the somewhat "spotty" immunosignal outlined in Fig. 8D. The observed AIS length change is then discussed in the context of a study conducted in a pharmacological model of myelin loss, however, that particular study (Hamada & Kole, 2015) found not only a length change but a position change after cuprizone-induced AIS plasticity. The authors should therefore discuss this finding in a bit more detail than simply stating "Adaptation of the AIS has been reported in the cuprizone chemical model of demyelination" (p. 14, ll. 512).

      Similarly to the points made about structural data above, the data from electrophysiological recordings should be presented in such a way that e.g. the number of cells and/or animals is readily accessible from the graph or legend. In its current form, this information - while available - needs to be pieced together from in-text information supplemented by figure legends. Sometimes, the authors do not include the number of animals behind individual cell data (for details please see author comments). Please carefully review all figures and edit accordingly.

      The behavioral data presented in the study is interesting, but the conclusions drawn are not supported by the data presented, as many unknown factors remain in place that could contribute to the observed phenotype.

    1. Reviewer #3 (Public Review):

      This work contributes to the literature characterizing early and late waves of transcription and associated chromatin remodeling following neuronal depolarization, here in cultured embryonic striatum. While they find IEG transcription 1h after depolarization, they find chromatin remodeling is slower (opening at the 4h time point). This may be due to chromatin at IEG regulatory regions already being open (in embryonic striatum), although previous work has found remodeling occurring at the 1h time point (in adult dentate gyrus). The authors next show that the chromatin remodeling that occurs at the late (4h) stage is largely in putative regulatory regions of the genome (rather than gene bodies), and is dependent on translation, which validates and extends the prior literature. The authors then transition from genome-wide basic neuroscience to focus on a specific gene of interest, prodynorphin (Pdyn), and a putative enhancer they identify from their chromatin analysis. They target CRISPR-activating and -inhibiting complexes to the putative enhancer and demonstrate that accessibility of this locus is necessary and sufficient for Pdyn transcription. They then show that at least one PDYN enhancer is conserved from rodents to humans, and is only activity-regulated in human GABAergic but not glutamatergic neurons. Finally, the authors generate snATAC-seq and show Pdyn gene and enhancer activity are also cell-type-specific in the rat striatum. The Pdyn work in particular is thorough and novel.

      Strengths:<br /> This work integrates multiple cutting-edge methods (multiple forms of genome-wide sequencing, combining new and published data across species, applying new forms of bioinformatic analysis, and targeted epigenome editing) to repeatedly and convincingly demonstrate these waves of chromatin remodeling and transcription. The figures and visual representations of data in particular set a new standard for the field. Although several findings within this paper are not novel, this paper ties previous findings all together in one place and goes on to show potential relevance for neuropsychiatric disorders beyond basic cellular neuroscience. The conclusions are mostly supported by the data.

      Results and conclusions that would benefit from clarification/extension.<br /> 1. Throughout the paper, the authors emphasize a "temporal decoupling" of transcriptional and chromatin response to depolarization, based on a lack of significant chromatin changes at 1h, despite IEG transcription. However, previous publications show significant chromatin remodeling at 1h (e.g. Su et al., NN 2017 in adult dentate gyrus) or 2h (Kim et al., Nature 2010; Malik et al., NN 2014 in cultured embryonic cortical neurons). The discussion briefly mentions this contrast, but it remains difficult to conclude decisively whether there is temporal decoupling when such decoupling is not found consistently. If one is to make broad conclusions about basic neural chromatin response to depolarization, it would be ideal to know under which conditions there is temporal decoupling, or if this is a region-specific phenomenon.

      2. The UMAP analysis is a novel way to probe transcription factor enrichment, but it's unclear what this is actually showing. The authors sought to ask whether "DARs could be separated based on transcription factor motifs in these regions." However, the motifs present in any genomic stretch are fixed based on genomic sequence, so it seems like this analysis might be asking whether certain motifs are more likely to be physically clustered together in the genome, in activity-regulated regions (rather than certain transcription factors acting in concert, as is implied in discussion). While still potentially interesting, this analysis does not seem to give much additional insight into activity-dependent chromatin remodeling beyond the motif enrichment analysis already performed. Nevertheless, to draw stronger conclusions, it would be necessary to compare clustering to a random set of genomic regions of the same length/size to interpret the clustering here. It would also be useful to know whether the ISL1 motif is also enriched in ubiquitously accessible genomic regions in the striatum (and not just DARs).

      3. The authors identify late-response gene enhancers by 3 criteria. However, only Pdyn was highlighted thereafter. How many putative DARs met these three criteria in striatum? Only Pdyn?

    1. Reviewer #3 (Public Review):

      This work provides a novel framework for semi-automatic segmentation and parcellation of brain tissues from fetal magnetic resonance imaging (MRI) by fusing an advanced deep learning technique and manual correction by experts. Over the broad age spectrum spanning newborns to adults, several fully-automatic segmentation/parcellation techniques have been proposed, showing robust, reliable performance across MR images with varying imaging quality. Unlike other age groups, however, scanning of the fetal brain is conducted in the womb; thus, there are additional and unique challenges, such as ambiguous positioning of the fetal brain, the surrounding maternal tissue in the fetal MRI, and fetal and maternal motion. These challenges in fetal MRI have collectively served as important bottlenecks in developing robust, reliable automatic segmentation/parcellation frameworks to date. This paper proposes a methodological framework for the segmentation and parcellation of fetal MRI scans using a two-step deep learning model, each for segmentation and parcellation. It is also noteworthy that the validity of the proposed framework has been extensively tested over different datasets with different image quality and different recording parameters, so the robust generalizability of the framework over other fetal MRI datasets is clearly suggested.

      Strengths:

      In general, a novel design framework, with separation of segmentation and parcellation schemes under each deep learning model, provides ample room for improving the model performance, as suggested by the results of this study. In addition, thanks to the flexibility in the model design (e.g., the choice of deep learning model) and parameters (e.g., manual correction step during training), an identical or similar framework can be easily extended to other datasets for different age groups or diagnostic groups/brain disorders. Another strength is the minimal requirement of human interaction after the training stage as significant time and effort of manual correction is often required following the automatic segmentation of fetal MR images. Lastly, thorough investigation of the inter-dataset generalizability of the proposed segmentation/parcellation framework will be well-received by the fetal neuroscience community.

      Weakness:

      The main weakness of this paper is the vague definition of the scientific novelty. By design, this paper is a technical study. The technical advancement claimed by the authors is a novel design of deep learning and a two-step deep-learning framework; each for segmentation and parcellation. There have been, however, other deep learning studies, and some share nearly identical model architecture to the one published by Asis-Cruz et al. (Frontiers in Neuroscience, 2022). As such the conceptual improvement in terms of deep learning model architecture is overstated. Regarding the separate framework for segmentation and parcellation, the conventional preprocessing protocol (e.g., Draw-EM; Makropoulos et al. IEEE Transactions on Medical Imaging, 2014) already presented a similar concept. Overall, it is unclear what unique technical advances have been made in the current paper.

      A second weakness of the work is the insufficient comparison to other conventional published methods. While the authors' claim that there is no "universally accepted" protocol for fetal brain segmentation/parcellation is at least partially true, Draw-EM, which was originally designed for neonatal brain segmentation, has been widely and successfully utilized in many fetal MRI studies, as discussed by the authors. Instead of a direct comparison to Draw-EM, the authors only performed a descriptive comparison using two exemplar MRI scans. It is unclear whether the superior performance of the proposed framework in these selected scans would be generalizable to others. Similarly, the authors claim that the proposed deep-learning-based segmentation/parcellation framework required minimal time for manual post-preprocessing refinement (1-3 mins), compared to 1-3 hours in another study using Draw-EM (Story et al. Neuroimage: Clinical, 2021). Again, this may not represent a fair comparison considering that the intensity/precision of manual refinement may differ depending on the different goals/objectives of other studies.

    1. Reviewer #2 (Public Review):

      In this study, the authors propose the possibility that some neurons in the enteric nervous system (ENS) originate postnatally from a non-ectodermal source. This possibility is investigated using a combination of transgenic lines, single cell RNA-sequencing (scRNA-seq), and immunofluorescence. Initially the authors identify a subset of neurons within myenteric enteric ganglia that are not lineage-labeled by canonical neural-crest derived cre-LoxP strategies. In their analysis, the group seeks to show that these neurons have an origin distinct from neural crest-derived progenitors that are known to initially colonize the developing gut. The team uses multiple cre lines (both Wnt1-cre and Pax3-cre) as well as several distinct reporter lines (ROSA-tdTomato, ROSA-EGFP, Hprt-tdTomato) to demonstrate that the lack of labeling by neural crest cre transgenes is consistent across several tools and not due to any transgene or reporter line artifact. Based on prior analysis that suggests some neurons in the ENS might be arising from a mesodermal lineage, the authors evaluate the possibility that mesoderm could contribute neurons to the ENS by evaluating expression of Tek-cre and Mesp1-cre tagged cell types in myenteric ganglia. The work with transgenic lines is convincing that some ENS neurons originate from an alternative source in the postnatal intestine and that this population increases in aging mice.

      The authors apply single cell RNA-sequencing to identify additional markers of these non-neural crest enteric neurons. They rely on dissociation of laminar gut muscle preparations, stripped from the outside of the adult intestine, that contain many cell types including smooth muscle, vasculature, and enteric ganglia. In the analysis of this scRNA-seq data, the authors focus on a cluster of cells in the resulting UMAP plots as being the MENs cluster based on labeling of this cluster with three genes (Calcb (CGRP), Met, and Cdh3). Based on expression of these marker genes there are a very large number of MENs and very few neural crest-derived enteric neurons (NENs) seen in the UMAPs. It is not clear why this difference in cell numbers has occurred. The early lineage tracing data shown with cre transgenes (Figures 1 and 2) shows relatively equal numbers of NENs and MENs in confocal imaging studies, yet in the RNA-seq UMAPs thousands of MENs are displayed while very few NENs are present. There is the possibility that the authors have identified a cell cluster as MENs that does not coincide with the Mesp1-cre or Tek-cre lineage labeled neurons observed within enteric ganglia of the laminar gut muscle preparations. The authors state that they have "used the single cell transcriptomics to both confirm the presence of MENs and identify more MEN-specific markers", however there is not a direct relationship made in this study between the MENs imaged and the cells profiled by single cell RNA-sequencing.

      In their analysis the authors note a difference in the percentage of enteric neurons labeled by the neural crest lineage tracer line, Wnt1-cre, relative to the total neurons labeled by the pan-neuronal marker HuC/D with age of the mice studied. They undertake a temporal analysis of the percentage of Wnt1-cre labeled neurons over total HuC/D neurons over the lifespan and note a decrease of Wnt1-cre labeled neurons with age. Further, the team assessed levels of growth factors that are known to promote proliferation and survival of NENs (GDNF-Ret signaling) versus factors known to promote growth of mesoderm (HGF) with age and document a decrease in GDNF-Ret signaling while HGF levels increase with age. The authors propose that the balance between these two signaling pathways is responsible for the shift in proportions of NENs versus MENs in aging animals.

      Some of the conclusions of this paper are supported, but several additional analyses are needed to reach the outcomes that the authors infer:

      1) Because the scRNA-seq data generated in this study derives from mixed cell populations present in laminar gut muscle preparations, there is a gap between the image data shown for the mesodermal cre lineage tracing and the MENs clusters the authors have selected in their single cell RNA-seq analysis. The absence of direct transcriptional profiling of cells labeled by Mesp1-cre or Tek1-cre expression prevents the authors from definitively connecting their in situ lineage labeling with specific clusters in the single cell RNA-seq analysis.

      2) Differential gene expression is the standard approach for identifying markers of a particular cluster and yet this is lacking in this study, and the rationale for why some genes were prioritized as markers of MENs is missing from the manuscript. Reanalysis of the authors posted single cell RNA-seq data found that genes integral to calling MENs (marker genes) were detectable in the data. Met, Cdh3, Calcb, Elavl2, Hand2, Pde10a, Vsnl1, Tubb2b, Stmn2, Stx3, and Gpr88 were all expressed in very few cells and at low levels. Given this, how were these genes chosen to be marker genes for MENs, especially given the low sequencing depth utilized?

      3) The authors rely on Phox2b as a marker for all ENS cells, including MENs. However, reprocessing of the authors posted single cell RNA-seq data finds that Phox2b is not detected in any of the cells in the MENs cluster and it's only expressed in very few cells of the neuroglia cluster. This discrepancy between the data the authors have generated and what is widely known about Phox2b expression in the ENS field must be explained as the absence of Phox2b message suggests there is an issue with reliance on low-depth scRNA-seq data for reaching the stated conclusions.

      4) The authors have not considered potential similarities between their MENs and other developing ENS lineages, like enteric mesothelial fibroblasts reported by Zeisel et al. 2018, and further analysis is needed to show that MENs are indeed a distinct cell type. Top marker genes of the author's MENs clusters were expressed more often in the clusters that were left out of Morarach et al 2021's E15.5 and E18.5 datasets because those clusters were mostly Phox2b-negative on UMAPs. This lack of Phox2b expression matches the characteristic of the MENs clusters' Phox2b-negative status in the authors single cell dataset. It is important to note that the Morarach dataset consists of Wnt1-cre lineage labeled (originating from neural crest) flow sorted cells. This is of import as it implies that Phox2b-negative cells ARE present within the Wnt1-cre lineage labeled population, an aspect that is relevant to this study's data analysis.

      5) Upon reprocessing of the authors MENs-genesis dataset with integration by sample as the authors describe, Met expression is evident within the cluster of NENs on the resulting UMAP plot and yet the authors rely on this gene as a marker of MENs. Whether Met expression is restricted to MENs should be resolved because the authors state it is exclusive to MENs and they subsequently investigate this gene across lifespan. Because it is not clear that Met is absent from neural crest derived enteric neurons this caveat complicates the interpretations of the present study.

      6) The authors apply MHCst immunofluorescence to mark MENs, but do not show any RNA expression for the MHCst transcripts in their single cell data. How did the authors come to the conclusion that MHCst IHC would be an appropriate marker for MENs? This rationale is missing from the text.

    1. Reviewer #3 (Public Review):

      Human complex traits including common diseases are highly polygenic (influenced by thousands of loci). This observation is in need of an explanation. The authors of this manuscript propose a model that competition for a single global resource (such as RNA polymerase II) may lead to a highly polygenic architecture of traits. Following an analytical examination, the authors reject their hypothesis. This work is of clear interest to the field. It remains to be seen if the model covers the variety of possible competition models.

    1. Reviewer #3 (Public Review):

      Wang et al. explored the unique biology of the deep-sea mussel Gigantidas platifrons to understand the fundamental principles of animal-symbiont relationships. They used single-nucleus RNA sequencing and validation and visualization of many of the important cellular and molecular players that allow these organisms to survive in the deep sea. They demonstrate that a diversity of cell types that support the structure and function of the gill including bacteriocytes, specialized epithelial cells that host sulfur-oxidizing or methane-oxidizing symbionts as well as a suite of other cell types including supportive cells, ciliary, and smooth muscle cells. By performing experiments of transplanting mussels from one habitat which is rich in methane to methane-limited environments, the authors showed that starved mussels may consume endosymbionts versus in methane-rich environments upregulated genes involved in glutamate synthesis. These data add to the growing body of literature that organisms control their endosymbionts in response to environmental change.

      The conclusions of the data are well supported. The authors adapted a technique that would have been technically impossible in their field environment by preserving the tissue and then performing nuclear isolation after the fact. The use of single-nucleus sequencing opens the possibility of new cellular and molecular biology that is not possible to study in the field. Additionally, the in-situ data (both WISH and FISH) are high-quality and easy to interpret. The use of cell-type-specific markers along with a symbiont-specific probe was effective. Finally, the SEM and TEM were used convincingly for specific purposes in the case of showing the cilia that may support water movement.

      The one particular area for clarification and improvement surrounds the concept of a proliferative progenitor population within the gill. The authors imply that three types of proliferative cells within gills have long been known, but their study may be the first to recover molecular markers for these putative populations. The markers the authors present for gill posterior end budding zone cells (PEBZCs) and dorsal end proliferation cells (DEPCs) are not intuitively associated with cell proliferation and some additional exploration of the data could be performed to strengthen the argument that these are indeed proliferative cells. The authors do utilize a trajectory analysis tool called Slingshot which they claim may suggest that PEBZCs could be the origin of all gill epithelial cells, however, one of the assumptions of this analysis is that differentiated cells are developed from the same precursor PEBZC population.

      However, these conclusions do not detract from the overall significance of the work of identifying the relationship between symbionts and bacteriocytes and how these host bacteriocytes modulate their gene expression in response to environmental change. It will be interesting to see how similar or different these data are across animal phyla. For instance, the work of symbiosis in cnidarians may converge on similar principles or there may be independent ways in which organisms have been able to solve these problems.

    1. Reviewer #3 (Public Review):

      In this manuscript, the authors describe the development of a machine-learning model to be used for gait assessment using insole data. They first developed a machine learning model using an existing, large data set of ground reaction forces collected during walking with force plates in a lab, from healthy adults and a group of people with knee injuries. Subsequently, they tested this model on ground reaction forces derived from insoles worn by a group of 19 healthy adults and a group of n=44 people with knee osteoarthritis (OA). The model was able to accurately identify individuals belonging to the knee OA group or the healthy group using the ground reaction forces during walking. Note: I do not have expertise on machine learning and will therefore refrain from reviewing the ML methods that were applied in this paper.

      Strengths: The authors successfully externally validated the trained model for GRF on insole data. Insole data carries potentially rich information, including the path of the CoP during the stance phase. The additional value of insoles over force plates in itself is clear, as insoles can be used independently of laboratory facilities. Moreover, insoles provide information on the COP path, which can have added value over other mobile assessment methods such as inertial sensors.

      Limitations: The second ML model, using only insole data to identify knee arthropathy from healthy subjects, was trained on a small sample of subjects. Although I have no background in ML, I can imagine that external validation in an independent and larger sample is needed to support the current findings.

      Gait speed has a major influence on the majority of gait-related outcomes. Slow or more cautious gait, due to pain or other causes, is reflected in vertical GRF's with less pronounced peaks. A difference in gait speed between people with pain in their knee (due to injury) and healthy subjects can be expected. This raises the question of what the added value of a model to estimate vertical GRF is over a simpler output (e.g. gait speed itself). Moreover, the paper does not elucidate what the added value of machine learning is over a simpler statistical model.

      In line with this issue, the current analyses are not strongly convincing me that the model described resulted in an identification of knee arthropathy-specific signature. Only knee arthropathy vs healthy (relatively young) subjects was compared, and we cannot rule out that this group only reflects general cautious, slow, or antalgic gait. As such, the data does not provide any evidence that the tool might be valuable to identify people with more or less severity of symptoms, or that the tool can be used to discriminate knee osteoarthritis from hip, or ankle osteoarthritis, or even to discriminate between people with musculoskeletal diseases and people with neurological gait disorders. This substantially limits the relevance for clinical (research) practice. In short, the output of the model seems to be restricted to "something is going on here", without further specification. Further development towards more specific aims using the insole data may substantially amplify clinical relevance.

    1. Reviewer #3 (Public Review):

      Hayashi et al., investigate the role of spinal neurons derived from the V2 progenitor domain. They identify a molecular marker, Hes2, specific to the V2 lineage in the spinal cord. The authors use this result to generate a new mouse line allowing specific access to the Hes2 lineage and show that this lineage is composed of excitatory V2a and inhibitory V2b spinal interneurons plus some populations of supraspinal neurons. Taking advantage of this new tool, they demonstrate that the developmental silencing of the Hes2 lineage leads to a disruption of mouse locomotor gait characterized by shorter strides and an increased cadence with no alteration of the alternation between flexion and extension. In addition, the authors show that the silencing of the Hes2 lineage also leads to an alteration of the interlimb coordination and a decreased capacity of the mice to achieve complex motor tasks. Using an intersectional genetic approach, the authors further demonstrate that the selective ablation of spinal V2 neurons in adult mice recapitulates the festination phenotype as well as the altered execution of complex motor tasks.

      By identifying a novel marker of the V2 lineage in the spinal cord and using this finding to generate a new mouse line Hayashi and colleagues suggest an intriguing interplay between excitatory and inhibitory V2 spinal neurons modulating differentially, multiple facets of motor behavior.

      The conclusions of this study are for the vast majority well supported by data. However, a few additional validations of the mouse model that is used and clarification about the methods of statistical analysis would improve the quality of this manuscript.

      1) Additional validations of the Hes2iCre mouse line generated and used in this study would improve the quality of the manuscript as well as shed light on the potential value of the use of the Hes2iCre mouse line for future investigations.

      - When reporting the cell population labeled by GFP in Hes2iCre; R26LSL-Sun1-GFP the authors need to report the number of animals on which these quantifications were performed to strengthen their conclusions (Figure 3C-E). Similarly, when showing the number of Hes2+, Chx10+ (V2a) and GATA3+ (V2b) neurons in Hes2iCre heterozygous vs homozygous the number of animals should be reported (Figure 3G; Figure S2E-F).

      - The numbers of Hes2+, Chx10+ (V2a) and GATA3+ (V2b) neurons in Hes2iCre heterozygous vs homozygous is reported. However, it would improve the validation of the mouse line, if the authors could provide a quantification of the numbers of Chx10+ and GATA3+ cells in heterogygous Hes2WT/iCre animals versus littermates lacking the Cre.

      - Although the study focus on spinal V2 neurons and the intersectional approach used in the last part of the paper is compelling, a better description of the supraspinal neurons that are part of the Hes2 lineage would give a better insight into the potential contribution of supraspinal Hes2 lineage to the motor phenotype described in Hes2-silenced mouse. In particular, an experiment showing if V2 (especially Chx10+ V2a) neurons from the medullary reticular nucleus are part of the Hes2 lineage would allow us to get a better grasp on the potential supraspinal effect of Hes2 neurons silencing.

      2) Adding a part in the methods explaining the statistical analysis applied is needed. In this part, the choices of the statistical analysis performed should be clearly explained and the assumptions stated. Although the intersectional genetic approach is challenging and does not allow for obtaining numerous animals, the use of parametric Student's t-tests on groups with only 4 animals is discussable and at least needs to be justified in the methods (results presented in Figure 6 and Figure S5). When the number of statistical units allows it, the normality of the distributions and the homoscedasticity should be tested prior to the use a parametric test. In some instances, tests taking into account the hierarchical structure of the data could be used. Furthermore, running statistical analysis on what seems to be a group of n=2 statistical units (Figure S3L) is not appropriate.

      3) Although this decision belongs to the authors, the use of the term "synergy" in the title and abstract might be misleading and might lead to confusion regarding the important outcome of this study. The authors show compelling evidence that the spinal ablation of the V2 lineage leads to a disruption of the ipsilateral coordination of body movements. However, as well explained by the authors, prior studies ablating individual V2a and V2b populations did not show any abnormal ipsilateral body coordination. This rather suggests a redundant or complementary function of inhibitory and excitatory V2 spinal neurons in spinal circuits, with the possibility for one individual population to compensate for the effect on the ipsilateral coordination following the ablation of the other population. Alternatively, "synergy" may suggest a simultaneous activity of V2a and V2b neurons that is not in the scope of this work.

    1. Reviewer #3 (Public Review):

      The authors previously showed that expressing formate dehydrogenase, rubisco, carbonic anhydrase, and phosphoribulokinase in Escherichia coli, followed by experimental evolution, led to the generation of strains that can metabolise CO2. Using two rounds of experimental evolution, the authors identify mutations in three genes - pgi, rpoB, and crp - that allow cells to metabolise CO2 in their engineered strain background. The authors make a strong case that mutations in pgi are loss-of-function mutations that prevent metabolic efflux from the reductive pentose phosphate autocatalytic cycle. The authors also argue that mutations in crp and rpoB lead to an increase in the NADH/NAD+ ratio, which would increase the concentration of the electron donor for carbon fixation. While this may explain the role of the crp and rpoB mutations, there is good reason to think that the two mutations have independent effects, and that the change in NADH/NAD+ ratio may not be the major reason for their importance in the CO2-metabolising strain.

      Specific comments:

      1. Deleting pgi rather than using a point mutation would allow the authors to more rigorously test whether loss-off-function mutants are being selected for in their experimental evolution pipeline. The same argument applies to crp.

      2. Page 10, lines 10-11, the authors state "Since Crp and RpoB are known to physically interact in the cell (26-28), we address them as one unit, as it is hard to decouple the effect of one from the other". CRP and RpoB are connected, but the authors' description of them is misleading. CRP activates transcription by interacting with RNA polymerase holoenzyme, of which the Beta subunit (encoded by rpoB) is a part. The specific interaction of CRP is with a different RNA polymerase subunit. The functions of CRP and RpoB, while both related to transcription, are otherwise very different. The mutations in crp and rpoB are unlikely to be directly functionally connected. Hence, they should be considered separately.

      3. A Beta-galactosidase assay would provide a very simple test of CRP H22N activity. There are also simple in vivo and in vitro assays for transcription activation (two different modes of activation) and DNA-binding. H22 is not near the DNA-binding domain, but may impact overall protein structure.

      4. There are many high-resolution structures of both CRP and RpoB (in the context of RNA polymerase). The authors should compare the position of the sites of mutation of these proteins to known functional regions, assuming H22N is not a loss-of-function mutation in crp.

      5. RNA-seq would provide a simple assay for the effects of the crp and rpoB mutations. While the precise effect of the rpoB mutation on RNA polymerase function may be hard to discern, the overall impact on gene expression would likely be informative.

  2. Jul 2023
    1. Reviewer #3 (Public Review):

      This work presents a novel approach for predicting fracture risk from high-resolution peripheral quantitative computed tomography (HR-pQCT): by training a deep learning model to predict five-year fracture risk where the sole input is the full 3D HR-pQCT image. Prior studies have developed models, of varying complexity, to predict fracture risk from HR-pQCT. However, this study is novel in that neither the typical manual efforts required for HR-pQCT image analysis nor additional biomarker collection are required, simplifying potential clinical implementation. The authors show that their model predicts fracture within five years with greater sensitivity than FRAX (with an assumed diagnostic threshold of FRAX > 20% or T-score < -2.5 SD), albeit with reduced specificity. The authors further investigate how their model output, the structural fragility score derived by artificial intelligence (SFS-AI), is correlated with two microarchitectural parameters that can be measured with HR-pQCT, demonstrating that their model captures many relevant characteristics of a patient's bone quality that cannot be captured by the standard clinical tools used to diagnose osteoporosis, and thus to identify patients at elevated risk of fracture.

      Strengths

      The authors use a very large dataset and a combination of state-of-the-art methods for training and validating their fracture prediction model: k-fold cross-validation is used for training and a held-out external test dataset is used to evaluate ensembled model predictions compared to the current clinical standard for fracture screening. The results with the test dataset show that the model can identify women at risk of fracture in the next five years with greater sensitivity than both FRAX with BMD and BMD alone.

      Because the model takes only a full 3D HR-pQCT image as input, the feasibility of clinical implementation is maximized. Standard morphological analysis with HR-pQCT is semi-automated and the labour required for the manual portions of analysis poses a significant barrier to clinical implementation. There is mounting evidence for the clinical utility of HR-pQCT (see Gazzotti et al. Br. J. Radiol. 2023) and fully automated models such as the one presented in this work will be critical for making clinical applications of HR-pQCT feasible.

      The authors quantify the contributions to the variance of the model output and examine activation maps overlaid on the HR-pQCT images. These sub-analyses indicate that the model is identifying relevant characteristics of hierarchical bone structure for fracture prediction that are not available from aBMD measurements from DXA and thus are not accounted for in the current standard clinical diagnostic tool.

      Weaknesses

      The authors make the claim that SFS-AI outperforms FRAX with BMD and BMD in terms of sensitivity and specificity of predicting fragility fractures within 5 years. This claim is supported by looking at the ROCs in figure 1, but the specific comparison made in the discussion is not completely fair as currently presented in the article. The thresholds of FRAX > 20% and T-score < -2.5SD were selected by the authors for binary comparison. FRAX and BMD achieve specificities of ~95% at these thresholds, while SFS-AI achieves a specificity of only 77% at the selected threshold, SFS-AI > 0.5. Conversely, SFS-AI achieves a sensitivity of 50% to 60% while FRAX and BMD achieve very poor sensitivities, between 4% and 16%. The authors have not justified their choice of binarization thresholds for FRAX or BMD by citing literature or clinical guidelines, nor have they motivated their choice of any of the thresholds with a discussion of how clinical considerations could influence the sensitivity-specificity trade-off. It is difficult to directly compare the prognosticative performance of SFS-AI to that of FRAX or BMD when the thresholds for FRAX and BMD are at such different locations on the respective ROCs when compared to where the threshold for SFS-AI places it on the ROC. The authors have also not compared their estimates of the sensitivity and specificity of FRAX and BMD to literature to provide important context for the comparison to SFS-AI. An additional unacknowledged limitation is that the FRAX tool is designed to predict 10-year fracture risk, while the outcome used to train the SFS-AI model and to compare to FRAX was 5-year fracture risk.

      Direct comparison may be impossible due to differences in study design or reported performance metrics, but the authors have not at all discussed the quantitative performance of prior models for fracture prediction or discrimination that use HR-pQCT (see Lu et al. Bone 2023 or Whittier et al. JBMR 2023) to contextualize the performance of their novel model. While the model presented in this article has the advantage that it does not require the typical expertise and manual effort needed for HR-pQCT image analysis, it is still important to acknowledge the potential trade-off of ease of implementation vs performance. Models that incorporate additional clinical data or that use standard HR-pQCT analysis outputs rather than raw images may perform well enough to justify the increase in the difficulty of clinical implementation or to motivate further work on fully automating microarchitectural analysis with HR-pQCT images.

      Finally, the article does not indicate that either the code used for model training or the trained model itself will be made publicly available. This limits the ability of future researchers to replicate and build on the results presented in the article.

    1. Reviewer #3 (Public Review):

      Royer et al. present a fully automated variant of the Barnes maze to reduce experimenter interference and ensure consistency across trials and subjects. They train mice in this maze over several days and analyze the progression of mouse search strategies during the course of the training. By fitting models involving stochastic processes, they demonstrate that a model combined of the random, spatial, and serial processes can best account for the observed changes in mice's search patterns. Their findings suggest that across training days the spatial strategy (using local landmarks) was progressively employed, mostly at the expense of the random strategy, while the serial strategy (consecutive nearby vestibule check) is reinforced from the early stages of training. Finally, they discuss potential mechanistic underpinnings within brain systems that could explain such behavioral adaptation and flexibility.

      Strength:<br /> The development of an automated Barnes maze allows for more naturalistic and uninterrupted behavior, facilitating the study of spatial learning and memory, as well as the analysis of the brain's neural networks during behavior when combined with neurophysiological techniques. The system's design has been thoughtfully considered, encompassing numerous intricate details. These details include the incorporation of flexible options for selecting start, goal, and proximal landmark positions, the inclusion of a rotating platform to prevent the accumulation of olfactory cues, and careful attention given to atomization, taking into account specific considerations such as the rotation of the maze without causing wire shortage or breakage. When combined with neurophysiological manipulations or recordings, the system provides a powerful tool for studying spatial navigation system.<br /> The behavioral experiment protocols, along with the analysis of animal behavior, are conducted with care, and the development of behavioral modeling to capture the animal's search strategy is thoughtfully executed. It is intriguing to observe how the integration of these innovative stochastic models can elucidate the evolution of mice's search strategy within a variant of the Barnes maze.

      Weakness:<br /> 1. The development of the well-thought-out automated Barnes maze may attract the interest of researchers exploring spatial learning and memory. However, this aspect of the paper lacks significance due to insufficient coverage of the materials and methods required for readers to replicate the behavioral methodology for their own research inquiries.<br /> Moreover, as discussed by the authors, the methodology favors specialists who utilize wired recordings or manipulations (e.g. optogenetics) in awake, behaving rodents. However, it remains unclear how the current maze design, which involves trapping mice in start and goal positions and incorporating angled vestibules resulting in the addition of numerous corners, can be effectively adapted for animals with wired implants.

      2. Novelty: In its current format, the main axis of the paper falls on the analysis of animal behavior and the development of behavioral modeling. In this respect, while it is interesting to see how thoughtfully designed models can explain the evolution of mice search strategy in a maze, the conclusions offer limited novel findings that align with the existing body of research and prior predictions.

      3. Scalability and accessibility: While the approach may be intriguing to experts who have an interest in or are familiar with the Barnes maze, its presentation seems to primarily target this specific audience. Therefore, there is a lack of clarity and discussion regarding the scalability of behavioral modeling to experiments involving other search strategies (such as sequence or episodic learning), other animal models, or the potential for translational applications. The scalability of the method would greatly benefit a broader scientific community. In line with this view, the paper's conclusions heavily rely on the development of new models using custom-made codes. Therefore, it would be advantageous to make these codes readily available, and if possible, provide access to the processed data as well. This could enhance comprehension and enable a larger audience to benefit from the methodology.

      4. Cross-validation of models: The authors have not implemented any measures to mitigate the risk of overfitting in their modeling. It would have been beneficial to include at least some form of cross-validation with stochastic models to address this concern. Additionally, the paper lacks the presence of analytics or measures that assess and compare the performance of the models.

      5. Quantification of inter-animal variations in strategy development: It is important to investigate, and address the argument concerning the possibility that not all animals recruit and develop the three processes (random, spatial, and serial) in a similar manner over days of training. It would be valuable to quantify the transition in strategy across days for each individual mouse and analyze how the population average, reflecting data from individual mice, corresponds to these findings. Currently, there is a lack of such quantification and analysis in the paper.

    1. Reviewer #3 (Public Review):

      The authors identified the mefenamic (Mef) binding site and DIDS binding site on the KCNQ1 KCNE1 complex. The authors also identified the mechanism of interactions using electrophysiological recording, calculating V1/2 of different mutants, and looking at the instantaneous and tail currents. The contribution of each residue within the binding pocket was analysed using GBSA and PBSA and traditional molecular dynamics simulation.

      The manuscript has been substantially revised from the previous version with a greater depth of computational analysis.

    1. Reviewer #3 (Public Review):

      The manuscript by Tejeda-Munoz examines signaling by Wnt and macropinocytosis in Xenopus embryos and colon cancer cells. A major problem with the study is the extensive use of pleiotropic inhibitors as "specific" inhibitors of macropinocytosis in embryos. It is true that BafA and EIPA block macropinocytosis, but they do many other things as well. A major target of EIPA is the NheI Na+/proton transporter, which also regulates invasive structures (podosomes, invadopodia) which could have major roles in development. Similarly, Baf1 will disrupt lysosomes and the endocytic system, which secondary effects on mTOR signaling and growth factor receptor trafficking. The authors cannot assume that processes inhibited by these drugs demonstrate a role of macropinocytosis. While correlations in tumor samples between increased expression of PAK1 and V0a3 and decreased expression of GSK3 are consistent with a link between macropinocytosis and Wnt-driven malignancy, the cell and embryo-based experiments do not convincingly make this connection. Finally, the data on FAK and TES are not well integrated with the rest of the manuscript.

      1. The data in Fig. 1A do not convincingly demonstrate macropinocytosis - it is impossible to tell what is being labeled by the dextran.

      2. The data in Fig. 2 do not make sense. LiCL2 bypasses the WNT activation pathway by inhibiting GSK3. If subsequent treatment with BafA blocks the effects of GSK3 inhibition, then BafrA is doing something unrelated to Wnt activation, whose target is the inhibition/sequestration of GSK3. While BafA might block GSK3 sequestration by inhibiting MVB function, it should have no effect on the inhibition of GSK3 by LiCl2.

      3. The effect of EHT on MP in SW480 cells is not clearly related to what is happening in the embryos. The nearly total loss of staining for Rac and -catenin after overnight EIPA does not implicate MP in protein stability - critical controls for cell viability and overall protein turnover are absent. Inhibition of WNT signaling might be expected to enhance -catenin turnover, but the effect on Rac1 is surprising. A more quantitative analysis by western blotting is required.

      4. The data on FAK inhibition and TES trafficking are poorly integrated with the rest of the paper.

    1. Reviewer #3 (Public Review):

      The work addresses challenges in linking anatomical information to transcriptomic data in single-cell sequencing. It proposes a method called Targeted Genetically-Encoded Multiplexing (TaG-EM), which uses genetic barcoding in Drosophila to label specific cell populations in vivo. By inserting a DNA barcode near the polyadenylation site in a UAS-GFP construct, cells of interest can be identified during single-cell sequencing. TaG-EM enables various applications, including cell type identification, multiplet droplet detection, and barcoding experimental parameters. The study demonstrates that TaG-EM barcodes can be decoded using next-generation sequencing for large-scale behavioral measurements. Overall, the results are solid in supporting the claims and will be useful for a broader fly community. I have only a few comments below:

      Specific comments:

      1. The authors mentioned that the results of structure pool tests in Fig. 2 showed a high level of quantitative accuracy in detecting the TaG-EM barcode abundance. Although the data were generally consistent with the input values in most cases, there were some obvious exceptions such as barcode 1 (under-represented) and barcodes 15, 20 (over-represented). It would be great if the authors could comment on these and provide a guideline for choosing the appropriate barcode lines when implementing this TaG-EM method.

      2. In Supplemental Figure 6, the authors showed GFP antibody staining data with 20 different TaG-EM barcode lines. The variability in GFP antibody staining results among these different TaG-EM barcode lines concerns the use of these TaG-EM barcode lines for sequencing followed by FACS sorting of native GFP. I expected the native GFP expression would be weaker and much more variable than the GFP antibody staining results shown in Supplemental Figure 6. If this is the case, variation of tissue-specific expression of TaG-EM barcode lines will likely be a confounding factor.

      3. As the authors mentioned in the manuscript, multiple barcodes for one experimental condition would be a better experimental design. Could the authors suggest a recommended number of barcodes for each experiential condition? 3? 4? Or more? Also, it would be great if the authors could provide a short discussion on the cost of such TaG-EM method. For example, for the phototaxis assay, if it is much more expensive to perform TaG-EM as compared to manually scoring the preference index by videotaping, what would be the practical considerations or benefits of doing TaG-EM over manual scoring?

    1. Reviewer #3 (Public Review):

      The study attempts to develop a Drosophila model for the human disease of LND. The issue here, and the main weakness of this study, is that Drosophila does not express the enzyme, HGPRT, which when mutated causes LND. The authors, instead, mutate the functionally-related Drosophila Aprt enzyme. However, it is unknown whether Aprt is also a structural homologue. Because of this, it will likely not be possible to identify pharmacological compounds that rescue HGPRT activity via a direct interaction (unless modelling predicts high conservation of substrate binding pocket between the two enzymes, etc). An additional weakness is that the study does not identify a molecule that may act as a lead compound for further development for treating LND. Rather, the various rescues reported are selective for only a subset of the disease-associated phenotypes. Thus, whilst informative, this first section of the study does not meet the study ambitions.

      The second approach adopted is to express a 'humanised mutated' form of HGPRT in Drosophila, which holds more promise for the development of a pharmacological screen. In particular, the locomotor defect is recapitulated but the seizure-like activity, whilst reported as being recapitulated, is debatable. A recovery time of 2.3 seconds is very much less than timings for typical seizure mutants. Nevertheless, the SING behaviour could be sufficient to screen against. However, this is not explored.

      In summary, this is a largely descriptive study reporting the behavioural effects of an Aprt loss-of-function mutation. RNAi KD and rescue expression studies suggest that a mix of neuronal (particularly dopaminergic and possibly adenosinergic signalling pathways) and glia are involved in the behavioural phenotypes affecting locomotion, sleep and seizure. There is insufficient evidence to have confidence that the Arpt fly model will prove valuable for understanding / treating LND.

    1. Reviewer #3 (Public Review):

      The authors thoroughly evaluate the performance and scalability of existing cell-type deconvolution methods. The paper builds on the existing knowledge by considering the suitability of deconvolution algorithms in the context of more challenging analyses where rare cell types are present or when dealing with unmatched references or noise introduced by a highly abundant cell type within the data. The paper also presents a new simulation framework for spatial transcriptomics data to support their benchmarking effort.

      ● Major strengths and weaknesses of the methods and results.

      While most of the benchmarking studies rely on publicly available spatial transcriptomics datasets, one of the major strengths of the paper is the additional evidence support from their silver standard datasets. Leveraging computational processes synthspot, the authors generated abundant synthetic spatial transcriptomics data with replicates. In addition, the data generation process also accounts for 9 different biological patterns to stay close to real data quality. The authors also communicated with the original authors of each benchmarked method to ensure correct implementation and optimal performance. Figure 2 provides a clear and concise summary of the benchmark results, which will be of great assistance to users who are contemplating conducting deconvolution analysis.

      The simulation setup has a significant weakness in the selection of reference single-cell RNAseq datasets used for generating synthetic spots. It is unclear why a mix of mouse and human scRNA-seq datasets were chosen, as this does not reflect a realistic biological scenario. This could call into question the findings of the "detecting rare cell types remains challenging even for top-performing methods" section of the paper, as the true "rare cell types" would not be as distinct as human skin cells in a mouse brain setting as simulated here. Furthermore, it is unclear why the authors developed Synthspot when other similar frameworks, such as SRTsim, exist. Have the authors explored other simulation frameworks? Finally, we would have appreciated the inclusion of tissue samples with more complex structures, such as those from tumors, where there may be more intricate mixing between cell types and spot types.

      The authors have effectively accomplished their objectives in benchmarking deconvolution methods by thoughtfully designing the experiments and selecting appropriate evaluation metrics. This paper will be highly beneficial for the community.

      This paper can provide guidance for selecting the most proper deconvolution methods under user-decided scenarios of the interests. Synthspot, allows for generating more realistic artificial tissue data with specific spatial patterns and is integrated as part of an easy-to-use and adaptable Nextflow pipeline. It might be worthwhile to clearly differentiate this work from previous work either in the benchmarking area or SRT data simulation area.

    1. Reviewer #3 (Public Review):

      Polygenic scores (PGS), constructed based on genetic effect sizes estimated in genome-wide association studies (GWAS) and used to predict phenotypes in humans have attracted considerable recent interest in human and evolutionary genetics, and in the social sciences. Recent work, however, has shown that PGSs have limited portability across ancestry groups, and that even within an ancestry group, their predictive accuracy varies markedly depending on characteristics such as the socio-economic status, age, and sex of the individuals in the samples used to construct them and to which they are applied. This study takes further steps in investigating and addressing the later problem, focusing on body mass index, a phenotype of substantial biomedical interest. Specifically, it quantifies the effects of a large number of co-variates and of interactions between these covariates and the PGS on prediction accuracy; it also examines the utility of including such covariates and interaction in the construction of predictors using both standard methods and artificial neural networks. This study would be of interest to investigators that develop and apply PGSs.

      I should add that I have not worked on PGSs and am not a statistician, and apologize in advance if this has led to some misunderstandings.

      Strengths:

      - The paper presents a much more comprehensive assessment of the effects of covariates than previous studies. It finds many covariates to have a substantial effect, which further highlights the importance of this problem to the development and application of PGSs for BMI and more generally.<br /> - The findings re the relationships between the effects of covariates and interactions between covariates and PGSs are, to the best of my knowledge, novel and interesting.<br /> - The development of predictors that account for multiple covariates and their interaction with the PGS are, to the best of my knowledge, novel and may prove useful in future efforts to produce reliable PGSs.<br /> - The improvement offered by the predictors that account for PGS and covariates using neural networks highlights the importance of non-linear interactions that are not addressed by standard methods, which is both interesting and likely to be of future utility.

      Weaknesses:

      - The paper would benefit substantially from extensive editing. It also uses terminology that is specific to recent literature on PGSs, thus limiting accessibility to a broader readership.<br /> - The potential meaning of most of the results is not explored. Some examples are provided below:<br /> • the paper emphasizes that 18/62 covariates examined show significant effects, but this result clearly depends on the covariates included. It would be helpful to provide more detail on how these covariates were chosen. Moreover, many of these covariates are likely to be correlated, making this result more difficult to interpret. Could these questions at least be partially addressed using the predictors constructed using all covariates and their interactions jointly (i.e., with LASSO)? In that regard, it would be helpful to know how many of the covariates and interactions were used in this predictor (I apologize if I missed that).<br /> • While the relationship between covariate effects and covariate-PGS interaction effects is intriguing, it is difficult to interpret without articulating what one would expect, i.e., what would be an appropriate null.<br /> • The finding that using artificial neural networks substantially improves prediction over more standard methods is especially intriguing, and highlights the potential importance of non-linear relationships between PGSs and covariates. These relationships remain hidden in a black box, however. Even fairly straightforward analyses, based on using different combinations of the PGS and/or covariates may shed some light on these relationships. For example, analyzing which covariates have a substantial effect on the prediction or varying one covariate at a time for different values of the PGS, etc.<br /> - The relationship to previous work should be discussed in greater detail.

    1. Reviewer #3 (Public Review):

      Braithwaite et al. present data from a comprehensive large-scale study of 18-month-old's visual attention. The authors leverage a battery of well-known visual attention tasks to replicate canonical effects found in the literature and assess the latent structure of these tasks. They find that, while controlling for eye tracking precision and accuracy, two factors best fit the data - attention to social and non-social stimuli.

      Strengths:<br /> The current study represents what amounts to years of hard work collecting data from a population that is challenging to work with - young children. The authors have diligently attended to data cleaning and sample size throughout the manuscript. Not only do they provide a large-scale replication of several well-known tasks, but they use advanced statistical modeling to discover the structure of visual attention in these 18-month-olds. Overall, this is a valuable contribution to the literature and provides a useful framework for studying visual attention development.

      Weaknesses:<br /> While the study is clearly a valuable addition to the extant literature, I have several concerns that might be addressed to improve the manuscript. These primarily center around clarity and conciseness. First, the introduction seems to lack clarity at times. For example, the first paragraph seems to introduce several ideas (e.g., brain and cognitive development, direct and indirect measures of cognition, eyetracking, etc) that make it hard to understand where the paper is going. The authors might consider homing in on 2 main points to motivate eye tracking as a tool. Second, there are many different eye tracking measures may make it difficult for the reader to track which measures were used for each task and which were relevant for the larger model. This may be remedied by adding a section to the methods that briefly describes how each measure was calculated and perhaps a table that lists each task, the measure, and how it was calculated. Third, the results are exciting but hard to visualize in the supplementary figures. I commend them on using raincloud plots to visualize the individual data, but I would strongly encourage the authors to rethink how they display the data. For example, I find the supplementary images hard to see and as a result the effects reported are hard to discern in the image. Fourth, I believe the current data warrant a deeper discussion of what these findings mean. For example, given the developmental nature of the current study, it would be valuable for the authors to discuss how the structure visual attention might change or stay the same across development. For example, do the authors believe the current two factor model would replicate in older children, or would exogenous and endogenous attention emerge as separable components? How do these predictions relate to the extensive research in the adult literature?

    1. Reviewer #3 (Public Review):

      The manuscript "Mechanical activation of TWIK-related potassium channel by nanoscopic movement and second messenger signaling" presents a new mechanism for the activation of TREK-1 channel. The mechanism suggests that TREK1 is activated by phosphatidic acids that are produced via a mechanosensitive motion of PLD2 to PIP2-enriched domains. Overall, I found the topic interesting, but several typos and unclarities reduced the readability of the manuscript. Additionally, I have several major concerns on the interpretation of the results. Therefore, the proposed mechanism is not fully supported by the presented data. Lastly, the mechanism is based on several previous studies from the Hansen lab, however, the novelty of the current manuscript is not clearly stated. For example, in the 2nd result section, the authors stated, "fluid shear causes PLD2 to move from cholesterol dependent GM1 clusters to PIP2 clusters and this activated the enzyme". However, this is also presented as a new finding in section 3 "Mechanism of PLD2 activation by shear."

      For PLD2 dependent TREK-1 activation. Overall, I found the results compelling. However, two key results are missing.<br /> 1. Does HEK cells have endogenous PLD2? If so, it's hard to claim that the authors can measure PLD2-independent TREK1 activation.<br /> 2. Does the plasma membrane trafficking of TREK1 remain the same under different conditions (PLD2 overexpression, truncation)? From Figure S2, the truncated TREK1 seem to have very poor trafficking. The change of trafficking could significantly contribute to the interpretation of the data in Figure 1.

      For shear-induced movement of TREK1 between nanodomains. The section is convincing, however I'm not an expert on super-resolution imaging. Also, it would be helpful to clarify whether the shear stress was maintained during fixation. If not, what is the time gap between reduced shear and the fixed state. lastly, it's unclear why shear flow changes the level of TREK1 and PIP2.

      For the mechanism of PLD2 activation by shear. I found this section not convincing. Therefore, the question of how does PLD2 sense mechanical force on the membrane is not fully addressed. Particularly, it's hard to imagine an acute 25% decrease cholesterol level by shear - where did the cholesterol go? Details on the measurements of free cholesterol level is unclear and additional/alternative experiments are needed to prove the reduction in cholesterol by shear.<br /> Importantly, there is no direct evidence for "shear thinning" of the membrane and the authors should avoid claiming shear thinning in the abstract and summary of the manuscript.

      The authors should also be aware that hypotonic shock is a very dirty assay for stretching the cell membrane. Often, there is only a transient increase in membrane tension, accompanied by many biochemical changes in the cells (including acidification, changes of concentration etc). Therefore, I would not consider this as definitive proof that PLD2 can be activated by stretching membrane.

    1. Reviewer #3 (Public Review):

      A landmark work (Chouhan et al., 2022) from the Sehgal group previously investigated the relationship between sleep and long-term memory formation by dissecting the role of mushroom body intrinsic neurons, extrinsic neurons, and output neurons during sleep-dependent and sleep-independent memory consolidation. In this manuscript, Li et al., profiled transcriptome in the anterior-posterior (ap) α'/β' neurons and identified genes that are differentially expressed after training in fed condition, which supports sleep-dependent memory formation. By knocking down candidate genes systematically, the authors identified Polr1F and Regnase-1 as two important hits that play potential roles in sleep and memory formation. What is the function of sleep and how to create a memory are two long-standing questions in science. The present study used a creative approach to identify novel components that may link sleep and memory consolidation in a specific type of neuron. Importantly, these components implicated that RNA processing may play a role in these processes.

      While I am enthusiastic about the innovative approach employed to identify RNA processing genes involved in sleep regulation and memory consolidation, I feel that the data presented in the manuscript is insufficient to support the claim that these two genes establish a definitive link between sleep and memory consolidation. First, the developmental role of Regnase-1 in reducing sleep remains unclear because knocking down Regnase-1 using the GeneSwitch system produced neither acute nor chronic sleep loss phenotype. To address potential confounding issues caused by the GeneSwtich system, I would suggest considering alternative methods, such as Gal80ts, to restrict the RNAi knockdown to adulthood. In addition, QPCR or other expression-measuring methods should be used to validate the specificity and efficiency of the knockdown. Further testing of additional RNAi fly lines and conducting overexpression experiments would also lend credibility to the phenotypes. Second, while constitutive Regnase-1 knockdown produced robust phenotypes for both sleep-dependent and sleep-independent memory, it also led to a severe short-term memory phenotype. This raises the possibility that flies with constitutive Regnase-1 knockdown are poor learners, thereby having little memory to consolidate. The defect in learning could be simply caused by chronic sleep loss before training. Thus, this set of results does not substantiate a strong link between sleep and long-term memory consolidation. Lastly, the discussion on the sequential function of training, sleep, and RNA processing on memory consolidation appears to be speculative based on the present data. While the novel approach did provide novel candidate genes with functions in sleep, memory, and potentially their link, the manuscript would greatly benefit from carefully adjusting the conclusions and incorporating rigorous validations for the RNAi knockdown experiments.

    1. Reviewer #3 (Public Review):

      In this manuscript, the authors investigated the effects of deletion of the ER-plasma membrane/Golgi tethering proteins tricalbins (Tcb1-3) on vacuolar morphology to demonstrate the role of membrane contact sites (MCSs) in regulating vacuolar morphology in Saccharomyces cerevisiae. Their data show that tricalbin deletion causes vacuolar fragmentation possibly in parallel with TORC1 pathway. In addition, their data reveal that levels of various lipids including ceramides, long-chain base (LCB)-1P and phytosphingosine (PHS) are increased in tricalbin-deleted cells. The authors find that exogenously added PHS can induce vacuole fragmentation and by performing analyses of genes involved in sphingolipid metabolism, they conclude that vacuolar fragmentation in tricalbin-deleted cells is due to the accumulated PHS in these cells. Importantly, exogenous PHS- or tricalbin deletion-induced vacuole fragmentation was suppressed by loss of the nucleus vacuole junction (NVJ), suggesting the possibility that PHS transported from the ER to vacuoles via the NVJ triggers vacuole fission.

      This work provides valuable insights into the relationship between MCS-mediated sphingolipid metabolism and vacuole morphology. The conclusions of this paper are mostly supported by their results, but there is concern about physiological roles of tricalbins and PHS in regulating vacuole morphology under known vacuole fission-inducing conditions. That is, in this paper it is not addressed whether the functions of tricalbins and PHS levels are controlled in response to osmotic shock, nutrient status, or ER stress.

      There is another weakness in their claim that the transmembrane domain of Tcb3 contributes to the formation of the tricalbin complex which is sufficient for tethering ER to the plasma membrane and the Golgi complex. Their claim is based only on the structural simulation, but not on biochemical experiments such as co-immunoprecipitation and pull-down.

    1. Reviewer #3 (Public Review):

      This manuscript deals with the sex-related gene, DMRT1, showing that it has a testis-promoting function in the rabbit. In loss-of-function studies in the mouse and human, DMRT1 has a role in testis maintenance after birth, although forced expression in the mouse can induce testis formation.

      The authors used CRISPR/Cas9 genome editing to generate DMRT1-/- rabbit embryos. The gonads of these embryos developed as ovaries. Interestingly, in addition Y-linked SRY, DMRT1 is required for timely up-regulation of SOX9 during Sertoli cell differentiation in the male gonad. This is quite different to the situation in mice, where Dmrt1 is not required in the testis until after birth (and Sry induced up-regulation of Sox9 hence does not require Dmrt1).

      The work adds to the field of sex determination by further broadening our understanding of the DMRT1 gene and the evolution of gonadal sex determination.

      In the Discussion section, it is suggested that DMRT1 could act as a pioneering factor to allow SRY action upon Sox9 in the rabbit model. The data show that DMRT1 may be more central to testis formation in mammals than previously considered. The work supports the notion that our understanding that the genetics of gonadal development (and indeed development more generally) should not rest solely on findings in the mouse.

    1. Reviewer #3 (Public Review):

      This study on drug repurposing presents the identification of potent activators of the Hippo pathway. The authors successfully screen a drug library and identify two CLK kinase inhibitors as YAP activators, with SM04690 targeting specifically CLK2. They further investigate the molecular basis of SM04690-induced YAP activity and identify splicing events in AMOTL2 as strongly affected by CLK2 inhibition. Exon skipping within AMOTL2 decreases the interactions with membrane bound proteins and is sufficient to induce YAP target gene expression. Overall the study is well designed, the conclusions are supported by sufficient data and represent an exciting connection between alternative splicing and the HIPPO pathway. The specificity of the inhibitor towards CLK2 and the mode of action via AMOTL2 could be supported by further data:

      1. The inconsistent inhibitor concentrations and varying results reported in the paper can be distracting. For instance, the response of endogenous targets to 100 nM concentration is described as a >5-fold increase in Figure 2B, whereas it is reported as a 1-1.5-fold response to 1000 nM in Figure 2D. This inconsistency should be addressed and clarified to provide a more accurate and reliable representation of the findings.<br /> 2. In the absence of a strong inhibitor induced YAP target gene expression (Figure 2D), it is difficult to conclude the dependency on YAP expression, as investigated by siRNA mediated knockdown. In a similar experiment, the dependency of the inhibitor on CLK2 expression could be confirmed<br /> 3. To further support the conclusion that CLK2 is the direct target of SM04690, it would be informative to investigate the effects of CLK1/4 inhibition on AMOTL2 exons (for example within RNA-seq data). If CLK1/4 inhibitors do not induce changes in AMOTL2 exons, it would strengthen the evidence for CLK2's role as the direct target. Including the results in the discussion would enhance the comprehensiveness of the study.<br /> 4. It would be important to determine the specific dose of SM04690 required to induce changes in AMOTL2 splicing. The authors observe that AMOTL2 protein levels appear unaffected at doses below 50 nM in Figure 3D, while YAP target genes are already affected at 20 nM in Figure 3G. Although Western blotting may not be the most sensitive method to detect minor changes in splicing, performing PCR experiments at lower doses could provide more insight into the splicing changes. Therefore, it is suggested that the authors include PCR experiments at lower doses to determine if changes in splicing are visible and to better establish the relationship between splicing and gene expression changes.

    1. Reviewer #3 (Public Review):

      The manuscript by Sun et al. reveals several crystal structures that help underpin the offensive-defensive relationship between the sea slug Aplysia kurodai and algae. These centre on TNA (a algal glycosyl hydrolase inhibitor), EHEP (a slug protein that protects against TNA and like compounds) and BGL (a glycosyl hydrolase that helps digest algae). The hypotheses generated from the crystal structures herein are supported by biochemical assays.

      The crystal structures of apo and TNA-bound EHEP reveals the binding (and thus protection) mechanism. The authors then demonstrate that the precipitated EHEP-TNA complex can be resolubilised at an alkaline pH, potentially highlighting a mechanism for EHEP recycling in the A. kurodai midgut. The authors also present the crystal structures of akuBGL, a beta-glucosidase utilised by Aplysia kurodai to digest laminarin in algae into glucose. The structure revealed that akuBGL is composed of two GH1 domains, with only one GH1 domain having the necessary residue arrangement for catalytic activity, which was confirmed via hydrolytic activity assays. Docking was used to assess binding of the substrate laminaritetraose and the inhibitors TNA, eckol and phloroglucinol to akuBGL. The docking studies revealed that the inhibitors bound akuBGL at the glycone-binding suggesting a competitive inhibition mechanism. Overall, most of the claims made in this work are supported by the data presented.

    1. Reviewer #3 (Public Review):

      Light energy drives photosynthesis. However, excessive light can damage (i.e., photo-damage) and thus inactivate the photosynthetic process. A major target site of photo-damage is photosystem II (PSII). In particular, one component of PSII, the reaction center protein, D1, is very suspectable to photo-damage, however, this protein is maintained efficiently by an elaborate multi-step PSII-D1 turnover/repair cycle. Two proteases, FtsH and Deg, are known to contribute to this process, respectively, by efficient degradation of photo-damaged D1 protein processively and endoproteolytically. In this manuscript, Kato et al., propose an additional step (an early step) in the D1 degradation/repair pathway. They propose that "Tryptophan oxidation" at the N-terminus of D1 may be one of the key oxidations in the PSII repair, leading to processive degradation of D1 by FtsH. Both, their data and arguments are very compelling.

      The D1 protein repair/degradation pathway in its simplest form can be defined essentially by five steps: (1) migration of damaged PSII core complex to the stroma thylakoid, (2) partial PSII disassembly of the PSII core monomer, (3) access of protease degrading damaged D1, (4) concomitant D1 synthesis, and (5) reassembly of PSII into grana thylakoid. An enormous amount of work has already been done to define and characterize these various steps. Kato et al., in this manuscript, are proposing a very early yet novel critical step in D1 protein turnover in which Tryptophan(Trp) oxidation in PSII core proteins influences D1 degradation mediated by FtsH.

      Using a variety of approaches, such as mass-spectrometry (Table 1), site-directed mutagenesis (Figures 2-4), D1 degradation assays (Figures 3, and 4), and simulation modeling (Figure 5), Kato et al., provide both strong evidence and reasonable arguments that an N-terminal Trp oxidation may be likely to be a 'key' oxidative post-translational modification (OPTM) that is involved in triggering D1 degradation and thus activating the PSII repair pathway. Consequently, from their accumulated data, the authors propose a scenario in which the unraveling of the N-terminal of the D1 protein facilitated by Trp oxidation plays a critical 'recognition' role in alerting the plant that the D1 protein is photo-damaged and thus to kick start the processive degradation pathway initiated possibly by FtsH. Coincidently, Forsman and Eaton-Rye (Biochemistry 2021, 60, 1, 53-63), while working with the thermophilic cyanobacterium, Thermosynechococcus vulcanus, showed that when the N-terminal DE-loop of the D1 protein is photo-damaged a disruption of the interaction between the PsbT subunit and D1 occurs which may serve as a signal for PSII to undergo repair following photodamage. While the activation of the processive degradation pathways in Chlamydomonas versus Thermosynechococcus vulcanus have significant mechanistic differences, it's interesting to note and speculate that the stability of the N-terminal of their respective D1 proteins seems to play a critical role in 'signaling' the PSII repair system to be activated and initiate repair. But it's complicated. For instance, significant Trp oxidation also occurs on the lumen side of other PSII subunits which may also play a significant role in activating the repair processes as well. Indeed, Kato et al.,( Photosynthesis Research volume 126, pages 409-416 (2015)) proposed a two-step model whereby the primary event is disruption of a Mn-cluster in PSII on the lumen side. A secondary event is damage to D1 caused by energy that is absorbed by chlorophyll. But models adapt, change, and get updated. And the data provided by Kato et al., in this manuscript, gives us a unique glimpse/snapshot into the importance of the stability of the N-terminal during photo-damage and its role in D1-turnover. For instance, the author's use site-directed mutagenesis of Trp residues undergoing OPTM in the D1 protein coupled with their D1 degradation assays (Figure 3 and 4), provides evidence that Trp oxidation (in particular the oxidation of Trp14) in coordination with FtsH results in the degradation of D1 protein. Indeed, their D1 degradation assays coupled with the use of a ftsh mutant provide further significant support that Trp14 oxidation and FtsH activity are strongly linked. But for FstH to degrade D1 protein it needs to gain access to photo-damaged D1. FtsH access to D1 is achieved by having CP43 partially dissociate from the PSII complex. Hence, the authors also addressed the possibility that Trp oxidation may also play a role in CP43 disassembly from the PSII complex thereby giving FtsH access to D1. Using a site-directed mutagenesis approach, they showed that Trp oxidation in CP43 appeared to have little impact on the PSII repair (Supplemental Figure S6). This result shows that D1-Trp14 oxidation appears to be playing a role in D1 turnover that occurs after CP43 disassembly from the PSII complex. Alternatively, the authors cannot exclude the possibility that D1-Trp14 oxidation in some way facilitates CP43 dissociation. Further investigation is needed on this point. However, D1-Trp14 oxidation is causing an internal disruption of the D1 protein possibly at the N-terminus of the protein. Consequently, the role of Trp14 oxidation in disrupting the stability of the N-terminal domain of the D1 protein was analyzed computationally. Using a molecular dynamics approach (Figure 5), the authors attempted to create a mechanistic model to explain why when D1 protein Trp14 undergoes oxidation the N-terminal domain of D1protein becomes unraveled. Specifically, the authors propose that the interaction between D1 protein Trp14 with PsbI Ser25 becomes disrupted upon oxidation of Trp14. Consequently, the authors concluded from their molecular dynamics simulation analysis that " the increased fluctuation of the first α-helix of D1 would give a chance to recognize the photo-damaged D1 by FtsH protease". Hence, the author's experimental and computational approaches employed here develop a compelling early-stage repair model that integrates 1) Trp14 oxidation, 2) FtsH activation and 3) D1- turnover being initiated at its N-terminal domain. However, a word of caution should be emphasized here. This model is just a snapshot of the very early stages of the D1 protein turnover process. The data presented here gives us just a small glimpse into the unique relationship between Trp oxidation of the D1 protein which may trigger significant N-terminal structural changes of the D1 protein that both signals and provides an opportunity for FstH to begin protease digestion of the D1 protein. However, the authors go to great lengths in their discussion section to not overstate solely the role of Trp14 oxidation in the complicated process of D1 turnover. The authors certainly recognize that there are a lot of moving parts involved in D1 turnover. And while Trp14 oxidation is the major focus of this paper, the authors show in Supplemental Fig S4 the structural positions of various additional oxidized Trp residues in the Thermosynecoccocus vulcans PSII core proteins. Indeed, this figure shows that the majority of oxidized Trps are located on the luminal side of PSII complex clustered around the oxygen-evolving complex. So, while oxidized Trp14 may be involved in the early stages of D1 turnover certainly oxidized Trps on the lumen side are also more than likely playing a role in D1 turnover as well. To untangle this complex process will require additional research.

      Nevertheless, identifying and characterizing the role of oxidative modification of tryptophan (Trp) residues, in particular, Trp14, in the PSII core provides another critical step in an already intricate multi-step process of D1 protein turnover during photo-damage.

    1. Reviewer #3 (Public Review):

      The data presented suggest that their algorithm can replace a human operator, which is a strong enough reason to publish and disseminate the technology. At the same time, aspects of the methods and results could benefit from a clearer explication. For example, the reported R^2 values for their model's performance are less than 0.5, (0.191, 0.2, 0.345, 0.467). I take this to mean the model's predictions are better than the mean value but that it will probably not generalize well for data it hasn't seen yet. Please comment.

      Did the authors partition their data into a training set, a validation set, and a test set? From the manuscript, it wasn't obvious to me they withheld a test set (a set of data never seen by the model, which they used to evaluate the performance of the model selected based on the validation set). From Extended Data Figures 1 and 2, I inferred that the number of samples in the confusion matrix matches the validation size (n=2341). So, are they reporting validation results and not test results? Please explain.

    1. Reviewer #3 (Public Review):

      In this manuscript, Zhou et al. demonstrate that the pseudokinase ULK4 has an important role in Hedgehog signaling by scaffolding the active kinase Stk36 and the transcription factor Gli2, enabling Gli2 to be phosphorylated and activated.<br /> Through nice biochemistry experiments, they show convincingly that the N-terminal pseudokinase domain of ULK4 binds Stk36 and the C-terminal Heat repeats bind Gli2.

      Lastly, they show that upon Sonic Hedgehog signaling, ULK4 localizes to the cilia and is needed to localize Stk36 and Gli2 for proper activation.

      This manuscript is very solid and methodically shows the role of ULK4 and STK36 throughout the whole paper, with well controlled experiments. The phosphomimetic and incapable mutations are very convincing as well.<br /> I think this manuscript is strong and stands as is, and there is no need for additional experiments.

      Overall, the strengths are the rigor of the methods, and the convincing case they bring for the formation of the ULK4-Gli2-Stk36 complex. There are no weaknesses noted. I think a little additional context for what is being observed in the immunofluorescence might benefit readers who are not familiar with these cell types and structures.

    1. Reviewer #3 (Public Review):

      The study by Thommen et al. sought to identify the native role of the Plasmodium falciparum FKBP35 protein, which has been identified as a potential drug target due to the antiplasmodial activity of the immunosuppressant FK506. This compound has multiple binding proteins in many organisms; however, only one FKBP exists in P. falciparum (FKBP35). Using genetically-modified parasites and mass spectrometry-based cellular thermal shift assays (CETSA), the authors suggest that this protein is in involved in ribosome homeostasis and that the antiplasmodial activity of FK506 is separate from its activity on the FKBP35 protein. The authors first created a conditional knockdown using the destruction domain/shield system, which demonstrated no change in asexual blood stage parasites. A conditional knockout was then generated using the DiCre system. FKBP35KO parasites survived the first generation but died in the second generation. The authors called this "a delayed death phenotype", although it was not secondary to drug treatment, so this may be a misnomer. This slow death was unrelated to apicoplast dysfunction, as demonstrated by lack of alterations in sensitivity to apicoplast inhibitors. Quantitative proteomics on the FKBP35KO vs FKBP35WT parasites demonstrated enrichment of proteins involved in pre-ribosome development and the nucleolus. Interestingly, the KO parasites were not more susceptible to cycloheximide, a translation inhibitor, in the first generation (G1), suggesting that mature ribosomes still exist at this point. The SunSET technique, which incorporates puromycin into nascent peptide chains, also showed that in G1 the FKBP35KO parasites were still able to synthesize proteins. But in the second generation (G2), there was a significant decrease in protein synthesis. Transcriptomics were also performed at multiple time points. The effects of knockout of FKBP35 were transcriptionally silent in G1, and the parasites then slowed their cell cycles as compared to the FKBP35WT parasites.

      The authors next sought to evaluate whether killing by FK506 was dependent upon the inhibition of PfKBP35. Interestingly, both FKBP35KO and FKBP35WT parasites were equally susceptible to FK506. This suggested that the antiplasmodial activity of FK506 was related to activity targeting essential functions in the parasite separate from binding to FKBP35. To identify these potential targets, the authors used MS-CETSA on lysates to test for thermal stabilization of proteins after exposure to drug, which suggests drug-protein interactions. As expected, FK506 bound FKBP35 at low nM concentrations. However, given that the parasite IC50 of this compound is in the uM range, the authors searched for proteins stabilized at these concentrations as putative secondary targets. Using live cell MS-CETSA, FK506 bound FKBP35 at low nM concentrations; however, in these experiments over 50 ribosomal proteins were stabilized by the drug at higher concentrations. Of note, there was also an increase in soluble ribosomal factors in the absence of denaturing conditions. The authors suggested that the drug itself led to these smaller factors disengaging from a larger ribosomal complex, leading to an increase in soluble factors. Ultimately, the authors conclude that the native function of FKBP35 is involved in ribosome homeostasis and that the antiplasmodial activity of FK506 is not related to the binding of FKBP35, but instead results from inhibition of essential functions of secondary targets.

      Strengths<br /> This study has many strengths. It addresses an important gap in parasite biology and drug development, by addressing the native role of the potential antiplasmodial drug target FKBP35 and whether the compound FK506 works through inhibition of that putative target. The knockout data provide compelling evidence that the KBP35 protein is essential for asexual parasite growth after one growth cycle. Analysis of the FKBP35KO line also provides evidence that the effects of FK506 are likely not solely due to inhibition of that protein, but instead must have secondary targets whose function is essential. These data are important in the field of drug development as they may guide development away from structure-based FK506 analogs that bind more specifically to the FKBP35 protein.

      Weaknesses:<br /> There are also a few notable weaknesses in the evidence that call into question the conclusion in the article title that FKBP35 is definitely involved in ribosomal homeostasis. While the proteomics supports alterations in ribosome biogenesis factors, it is unclear whether this is a direct role of the loss of the FKBP35 protein or is more related to non-specific downstream effects of knocking down the protein. The CETSA data clearly demonstrate that FK506 binds PfKB35 at low nM concentrations, which is different than the IC50 noted in the parasite; however, the evidence that the proteins stabilized by uM concentrations of drug are actual targets is not completely convincing. Especially, given the high uM amounts of drug required to stabilize these proteins. This section of the manuscript would benefit from validation of a least one or two of the putative candidates noted in the text. In the live cell CETSA, it is noted that >50 ribosomal components are stabilized in drug treated but not lysate controls. Similarly, the authors suggest that the -soluble fraction of ribosomal components increases in drug-exposed parasites even at 37{degree sign}C and suggests that this is likely from smaller ribosomal proteins disengaging from larger ribosomal complexes. While the evidence is convincing that this protein may play a role in ribosome homeostasis in some capacity, it is not sure that the title of the paper "FKBP secures ribosome homeostasis" holds true given the lack of mechanistic data. A minor weakness, but one that should nonetheless be addressed, is the use of the term "delayed death phenotype" with regards to the knockout parasite killing. This term is most frequently used in a very specific setting of apicoplast drugs that inhibit apicoplast ribosomes, so the term is misleading. It is also possible that the parasites are able to go through a normal cycle because of the kinetics of the knockout and that the time needed for protein clearance in the parasite to a level that is lethal.

      Overall, the authors set out to identify the native role of FKB35 in the P. falciparum parasites and to identify whether this is, in fact, the target of FK506. The data clearly demonstrate that FKBP35 is essential for parasite growth and provide evidence that alterations in its levels have proteomic but not transcriptional changes. However, the conclusion that FKBP35 actually stabilizes ribosomal complexes remains intermediate. The data are also very compelling that FK506 has secondary targets in the parasite aside from FKBP35; however, the high uM concentrations of the drug needed to attain results and the lack of biological validation of the CETSA hits makes it difficult to know whether any of these are actually the target of the compound or instead are nonspecific downstream consequences of treatment.

    1. Reviewer #3 (Public Review):

      GluK1 forms glutamate-gated ion channels with an important function in synaptic transmission and neuron excitability. Particularly, a GluK1 splice-variant (Gluk1-1) with significant expression in different regions of the brain has not been characterized before. The paper of Dhingra et al. aims to evaluate the role of the Exon 9 splice insert in GluK1 on channel function. This study relies mainly on electrophysiological approaches to determine the effect of the splice insert on GluK1 gating properties, including desensitization, agonist efficacy, recovery, and rectification. Overall, this work provides two major milestones: 1) the first functional characterization of the Gluk1-1a variant and 2) the first structure of this channel. The functional data supporting the role of the insert on channel properties are solid, although the current data does not provide significant insights about the mechanisms behind this. Also, the little information associated with the resolved structure precludes providing further insights about the structural basis that account for the impact of the insert on channel function. Overall, I consider this an interesting paper that represents an important advance in the study of glutamate receptors.

    1. Reviewer #3 (Public Review):

      Lee, Kyungtae and colleagues have discovered and mapped out alpha-arrestin interactomes in both human and Drosophila through the affinity purification/mass spectrometry and the SAINTexpress method. They found the high confident interactomes, consisting of 390 protein-protein interactions (PPIs) between six human alpha-arrestins and 307 preproteins, as well as 740 PPIs between twelve Drosophila alpha-arrestins and 467 prey proteins. To define and characterize these identified alpha-arrestin interactomes, the team employed a variety of widely recognized bioinformatics tools. These included protein domain enrichment analysis, PANTHER for protein class enrichment, DAVID for subcellular localization analysis, COMPLEAT for the identification of functional complexes, and DIOPT to identify evolutionary conserved interactomes. Through these analyses, they confirmed known alpha-arrestin interactors' role and associated functions such as ubiquitin ligase and protease. Furthermore, they found unexpected biological functions in the newly discovered interactomes, including RNA splicing and helicase, GTPase-activating proteins, ATP synthase. The authors carried out further study into the role of human TXNIP in transcription and epigenetic regulation, as well as the role of ARRDC5 in osteoclast differentiation. This study holds important value as the newly identified alpha-arrestin interactomes are likely aiding functional studies of this group of proteins. Despite the overall support from data for the paper's conclusions, certain elements related to data quantification, interpretation, and presentation demand more detailed explanation and clarification.

      1) In Figure 1B, it is shown that human alpha-arrestins were N-GFP tagged (N-terminal) and Drosophila alpha-arrestins were C-GFP (C-terminal). However, the rationale of why the authors used different tags for human and fly proteins was not explained in the main text and methods.<br /> 2) In Figure 2A, there seems to be an error for labeling the GAL4p/GAL80p complex that includes NOTCH2, NOTCH1 and TSC2.<br /> 3) In Figure 5, given that knockdown of TXNIP did not affect the levels and nuclear localization of HDAC2, the authors suggest that TXNIP might modulate HDAC2 activity. However, the ChiP assay suggest a different model - TXNIP-HDAC2 interaction might inhibit the chromatin occupancy of HDAC2, reducing histone deacetylation and increasing global chromatin accessibly. The authors need to propose a model consistent with these sets of all data.<br /> 4) The authors showed that ectopic expression of ARRDC5 increased osteoclast differentiation and function. Does loss of ARDDC5 lead to defects in osteoclast function and fate determination?<br /> 5) From Figure 6D, the authors argued that ARRDC5 overexpression resulted in more V-ATPase signals: however, there is no quantification. Quantification of the confocal images will foster the conclusion. Also, western blots for V-ATPase proteins will provide an alternative way to determine the effects of ARRDC5.<br /> 6) The results from Figure 6D did not support the authors' argument that ARRDC5 might control the membrane localization of the V-ATPase, as bafilomycin is the V-ATPase inhibitor. ARRDC5 knockdown experiments will help to determine whether ARRDC5 can control the membrane localization of the V-ATPase in osteoclast.

    1. most people don't realize how vulnerable we are I mean for example the the food supply in the average city in the United States if it's not daily 00:01:44 renewed would run out in about three days there's not much of a buffer there
      • food supply chain vulnerability
      • most US cities would run out of food in 3 days if there was a major food supply chain disruption
    1. Reviewer #3 (Public Review):

      The authors generated a novel sfGFP::Aβ C. elegans models of AD that expresses Abeta aggregates extracellularly; using this worm model, they identified that a disintegrin and metalloprotease ADM-2, an ortholog of human ADAM9, participated in removing these extracellular aggregates. This worm model may be very useful to the AD field after further characterization.

      A novelty of this paper is the generation of a worm model of AD that produces extracellular Abeta aggregates, mimicking one of the two disease-defining pathological features of AD. The authors have also identified a protein which inhibits Abeta aggregation in the AD worm model; if these data are relevant to humans, they may reveal a new druggable target against AD.

    1. Reviewer #3 (Public Review):

      The study, performed in the animal model C. elegans, aims at characterizing functional differences in the meiosis-specific kleisins, REC-8 and COH-3/4.<br /> The authors conclude that in worms the identity of the kleisin subunit of the cohesin complex determines whether cohesin promotes cohesion, or controls higher-order chromosome structure. COH-3/4 is highly abundant and dynamic and responds to SCC-2 and WAPL-1. In contrast, REC-8 complexes associate stably and in low abundance and are resistant to SCC-2 and WAPL-1 perturbations.

      Main points:

      This study is a continuation and partially a repeat of a study Castellano-Pozo & Martinez-Perez published in Nat. Comm. 2020, in which they depleted COH-3/4 and REC-8 by injecting TEV and cleaved artificially engineered TEV sites in these kleisins.The results were slightly different though, as the authors concluded: "Disassembly of axial elements requires simultaneous removal of REC-8 and COH-3/4."

      The current study uses a degron instead of TEV and SIM to revisit the same result. This time, degradation of COH-3/4 alone, but not of Rec8 alone completely eliminates axial elements. It seems that, if the conclusion is now correct, the previous headline must be incorrect, showing that more care has to be taken in the conclusions.

      One new experiment in this study is the degradation of scc-2::AID::GFP. The authors treat the germline with auxin for 14 hours. How long scc-2::AID actually needs for degradation and thus, how long cells actually remain without SCC-2, is unknown. What is definitely needed is a serious analysis of the speed of degradation of Scc2 in the various stages.

      It is currently not possible to estimate, as the authors do, how long cells have been without SCC-2. This estimation assumes an immediate depletion of SCC-2.<br /> If this were indeed the case, then depletion intervals should be much shorter, because the important primary phenotypes occur immediately after depletion, not 14 hours later.

    1. Reviewer #3 (Public Review):

      This paper was a significant and commendable effort, given all the challenges in TB genetics research. It was generally well written and analyses well done. Analytical methods were appropriate. The inclusion of polygenic heritability estimates is also nice to have within this large work. There is also a wealth of supplemental data provided, which will be useful to the field.

      However, there are a number of important weaknesses that need to be addressed. These are listed here, and recommended revisions are addressed in the recommendations section:<br /> 1. As the authors point out, one of the challenges in this work is the varying phenotype definitions (diagnosis of TB cases, definition of controls) across all the included genetic studies. Table S1 is critical for this, however it is missing information, and some of the information is unclear. More importantly, the authors state multiple times that there is no evidence of heterogeneity due to these variable phenotype definitions, and that genetic ancestry contributes more to differences in effect sizes between GWAS than study design. However, these two things are confounded - different study designs / phenotype definitions were used in studies of different ancestry.<br /> 2. The polygenic heritability analysis table is not explained very well.<br /> 3. The supplemental data file is not very helpful without some sort of guide. It isn't clear whether the wealth of candidate genes that have been studied in TB were examined in these data. That would be a great benefit of this work.<br /> 4. There needs to be clarity on how unpublished works were sought. In non-genetic meta-analyses, there is usually some detail about a process of contacting authors, etc. There needs to be some assurance that every attempt was made to collect all the relevant data. It is also not clear why family-based analyses could not be included considering that summary statistics were the basis of analysis.<br /> 5. It is rather surprising that only one locus meets genome-wide significance. The authors do explain this well in terms of the ancestry-specific effects driving these results, but it is also surprising that no candidate genes (that had not been discovered in GWAS studies, but were rather studied separately) did not rise to some higher significance threshold.

    1. Reviewer #3 (Public Review):

      Liu and colleagues examined learning and brain plasticity in neurotypical children and children with autism. The main findings include autistic children relying more on rule-based versus memory-based learning strategies, altered associations between learning gains and brain plasticity in children with autism, and insistence on sameness as a moderator between brain plasticity and learning in autism. Although the sample size is limited in this study, the findings provide a significant contribution to the field.

      The major strengths of this paper include an extensive pre and post training protocol, a detailed methods section, rationale behind the study, investigation of a potential moderator of learning gains and neural plasticity, and investigation of "neural plasticity" in association to learning in autism.

      Weaknesses of the study include a small sample size, and some missing information/analyses from the study.

      The authors laid out four clear aims of the study. They investigated these aims and the analytic approaches were appropriate.

      The paper included significant findings toward better understanding the mechanisms underlying differences in learning strategies and behavior in children diagnosed with autism spectrum disorder. This holds significant value in educational and classroom settings. Further, the investigation of a potential moderator of learning gains and neural plasticity provides a potential mechanism to improve the relationship. Overall, this is a significant contribution to the field.

      The autism literature is limited in understanding differences in learning styles and the underlying neural mechanisms of these differences.

    1. Reviewer #3 (Public Review):

      In this paper, the authors report cervical cancer screening practice during the covid pandemic in the US from the perspective of health professionals (HPs). Two methods were used: survey and regression analysis, and qualitative interviews. Analyses indicated that older, non-White, internal medicine, and family medicine clinicians and those practicing in community health centers had higher odds of reporting reduced screening. Interviews highlighted disruptions of services and a lack of tracking systems.<br /> The strengths of the paper are mainly i) using three different sources of HPs' recruitment and ii) being able to recruit a large number of participants in both survey and interviews and iii) the demographic characteristics of the interviewees were similar to those of the participants of the survey.

    1. Reviewer #3 (Public Review):

      Once inside a cellular vacuole, Salmonella senses the low pH and activates the transcriptional regulator SsrB to induce expression of the Salmonella pathogenicity island 2 genes that are essential for intracellular survival and replication inside the host. This study investigates the mechanisms by which SsrB senses the pH changes, and with a series of elegant experiments identify a conserved residue in the receiver domain, His12, as essential for pH sensing and Salmonella virulence.

      Overall, this study identifies an important mechanism of pathogen virulence, which could be targeted to control intracellular replication of the pathogen. The experiments are well conducted, the manuscript is clearly written, and the data are convincing and well presented. The authors perform a logical and detailed analysis of several portions of SsrB to finally identify His12 as a key residue for pH sensing. This was not an easy task. Moreover, the fact that a single amino acid appears to be so important for SsrB pH sensing and SsrB phosphorylation is an important finding for potentially targeting SsrB and inhibiting Salmonella virulence.

    1. Reviewer #3 (Public Review):

      The work proposes a model of neural information processing based on a 'synergistic global workspace,' which processes information in three principal steps: a gatekeeping step (information gathering), an information integration step, and finally, a broadcasting step. The authors determined the synergistic global workspace based on previous work and extended the role of its elements using 100 fMRI recordings of the resting state of healthy participants of the HCP. The authors then applied network analysis and two different measures of information integration to examine changes in reduced states of consciousness (such as anesthesia and after-coma disorders of consciousness). They provided an interpretation of the results in terms of the proposed model of brain information processing, which could be helpful to be implemented in other states of consciousness and related to perturbative approaches. Overall, I found the manuscript to be well-organized, and the results are interesting and could be informative for a broad range of literature, suggesting interesting new ideas for the field to explore. However, there are some points that the authors could clarify to strengthen the paper. Key points include:

      1. The work strongly relies on the identification of the regions belonging to the synergistic global workspace, which was primarily proposed and computed in a previous paper by the authors. It would be great if this computation could be included in a more explicit way in this manuscript to make it self-contained. Maybe include some table or figure being explicit in the Gradient of redundancy-to-synergy relative importance results and procedure.

      2. It would be beneficial if the authors could provide further explanation regarding the differences in the procedure for selecting the workspace and its role within the proposed architecture. For instance, why does one case uses the strength of the nodes while the other case uses the participation coefficient? It would be interesting to explore what would happen if the workspace was defined directly using the participation coefficient instead of the strength. Additionally, what impact would it have on the procedure if a different selection of modules was used? For example, instead of using the RSN, other criteria, such as modularity algorithms, PCA, Hidden Markov Models, Variational Autoencoders, etc., could be considered. The main point of my question is that, probably, the RSN are quite redundant networks and other methods, as PCA generates independent networks. It would be helpful if the authors could offer some comments on their intuition regarding these points without necessarily requiring additional computations.

      3. The authors acknowledged the potential relevance of perturbative approaches in terms of PCI and quantification of consciousness. It would be valuable if the authors could also discuss perturbative approaches in relation to inducing transitions between brain states. In other words, since the authors investigate disorders of consciousness where interventions could provide insights into treatment, as suggested by computational and experimental works, it would be interesting to explore the relationship between the synergistic workspace and its modifications from this perspective as well.

    1. Reviewer #3 (Public Review):

      The study by Ngodup and colleagues describes the contribution of sodium leak NALCN conductance on the effects of noradrenaline on cartwheel interneurons of the DCN. The manuscript is very well-written and the experiments are well-controlled. The scope of the study is of high biological relevance and recapitulates a primary finding of the Khaliq lab (Philippart et al., eLife, 2018) in ventral midbrain dopamine neurons, that Gi/o-coupled receptors inhibit NALCN current to reduce neuronal excitability. Together these studies provide unequivocable evidence for NALCN as a downstream target of these receptors. There are no major concerns. I have only minor suggestions:

      Minor<br /> 1. As introduced in the introduction, NALCN is inhibited by extracellular calcium which has led to some discourse of the relevance of NALCN when recorded in 0.1 mM calcium. A strength of this study is the effect of NA on NALCN is recorded in physiological levels of calcium (1.2 mM). I suggest including the concentration of extracellular calcium in the aCSF in the Results section instead of relying on the reader to look to the Methods.

      2. It would be interesting to include the basal membrane properties of the KO compared to wildtype, including membrane resistance and resting membrane potential. From the example recording in Figure 2, one might think that the KOs have lower membrane resistance, so it is interesting that the 2 mV hyperpolarization produced similar effects on rheobase. In addition, from the example in Figure 2G, it appears that NA has an effect on firing frequency with large current injection in the KO. Is this true in grouped data and if so, is there any speculation into how this occurs?

      3. Please expand on the rationale for why GABAB and alpha2 must be physically close to NALCN. To my knowledge, the mechanism by which these receptors inhibit NALCN is not known. Must it be membrane-delimited?

    1. Reviewer #3 (Public Review):

      Functional and anatomical studies of spinal circuitry in vertebrates have formed the basis of our understanding of neuronal control of movements. Larval zebrafish provide a simplified system for deciphering spinal circuitry. In this manuscript, the authors performed scRNAseq on spinal cord neurons in larval zebrafish, identifying major classes of neuronal and glial types. Through transcriptome analysis, they validated several key interneuron types previously implicated in zebrafish locomotion circuitry. The authors went beyond identifying transcriptional markers and explored synaptic molecules associated with the strength of motor output. They discovered molecular distinctions causally related to the unique physiology of primary motoneuron (PMn) function, which involves providing strong synaptic outputs for escapes and fast swimming. They defined functional 'cassettes' comprising specific combinations of voltage-dependent ion channel types and synaptic proteins, likely responsible for generating maximal motor outputs.

    1. Reviewer #3 (Public Review):

      Syntactic parsing is a highly dynamic process: When an incoming word is inconsistent with the presumed syntactic structure, the brain has to reanalyze the sentence and construct an alternative syntactic structure. Since syntactic parsing is a hidden process, it is challenging to describe the syntactic structure a listener internally constructs at each time moment. Here, the authors overcome this problem by (1) asking listeners to complete a sentence at some break point to probe the syntactic structure mentally constructed at the break point, and (2) using a DNN model to extract the most likely structure a listener may extract at a time moment. After obtaining incremental syntactic features using the DNN model, the authors analyze how these syntactic features are represented in the brain using MEG.

      Although the analyses are detailed, the current conclusion needs to be further specified. For example, in the abstract, it is concluded that "Our results reveal a detailed picture of the neurobiological processes involved in building structured interpretations through the integration across multifaceted constraints". The readers may remain puzzled after reading this conclusion.

      Similarly, for the second part of the conclusion, i.e., "including an extensive set of bilateral brain regions beyond the classical fronto-temporal language system, which sheds light on the distributed nature of language processing in the brain."<br /> The more extensive cortical activation may be attributed to the spatial resolution of MEG, and it is quite well acknowledged that language processing is quite distributive in the brain.

      The authors should also discuss:

      (1) individual differences (whether the BERT representation is a good enough approximation of the mental representation of individual listeners).

      (2) parallel parsing (I think the framework here should allow the brain to maintain parallel representations of different syntactic structures but the analysis does not consider parallel representations).

    1. Reviewer #3 (Public Review):

      Vitamin A is critical for the development of the brain and for neuronal function and plasticity, however the mechanisms responsible for the uptake of retinol across the blood brain barrier (BBB) are currently not known. The authors investigate vitamin A uptake across the blood brain barrier using an in vitro model based on endothelial cells differentiated from human derived induced pluripotent stem cells. Using recombinant cargo proteins and radioactive tracers the authors then propose a mechanism and a kinetic model for the uptake of retinol across the BBB that requires serum retinol binding protein 4 (RBP4 or RBP) and its receptor stimulated by retinoic acid 6 (STRA6). The results support a concentration dependent mechanism of transport combining a rapid fluid-phase retinol and a slower directed RBP-complexed retinol across the BBB. The data also hint at the potential regulatory roles of TTR on this process independent of its interaction with RBP.

      Strengths:<br /> The studies are rigorous and careful and the authors consider free retinol uptake from the fluid-phase in addition to evaluating RBP-TTR and RBP-STRA6 interactions.<br /> The antibody to STRA6 is validated.<br /> The experiments performed are clearly described.

      Weaknesses:<br /> The results presented do not offer significant new information regarding the uptake of retinol by tissues beyond what is known and published using genetic, structural and biochemical approaches.<br /> The use of the iPSC-derived BBB model is potentially interesting but this could have been complemented by a thorough genetic dissection of the cellular factors required for the uptake, transcellular transport, and secretion of retinol by the brain endothelial cells.<br /> The conclusions derived are not well supported by the data presented.<br /> It is difficult to infer a mechanism or to derive a meaningful conclusion regarding the in vivo relevance of the results presented.

    1. Reviewer #3 (Public Review):

      Here, the authors trained catElMo, a new context-aware embedding model for TCRβ CDR3 amino acid sequences for TCR-epitope specificity and clustering tasks. This method benchmarked existing work in protein and TCR language models and investigated the role that model architecture plays in the prediction performance. The major strength of this paper is comprehensively evaluating common model architectures used, which is useful for practitioners in the field. However, some key details were missing to assess whether the benchmarking study is a fair comparison between different architectures. Major comments are as follows:

      - It is not clear why epitope sequences were also embedded using catELMo for the binding prediction task. Because catELMO is trained on TCRβ CDR3 sequences, it's not clear what benefit would come from this embedding. Were the other embedding models under comparison also applied to both the TCR and epitope sequences? It may be a fairer comparison if a single method is used to encode epitope sequence for all models under comparison, so that the performance reflects the quality of the TCR embedding only.<br /> - The tSNE visualization in Figure 3 is helpful. It makes sense that the last hidden layer features separate well by binding labels for the better performing models. However, it would be useful to know if positive and negative TCRs for each epitope group also separate well in the original TCR embedding space. In other words, how much separation between these groups is due to the neural network vs just the embedding?<br /> - To generate negative samples, the author randomly paired TCRs from healthy subjects to different epitopes. This could produce issues with false negatives if the epitopes used are common. Is there an estimate for how frequently there might be false negatives for those commonly occurring epitopes that most populations might also have been exposed to? Could there be a potential batch effect for the negative sampled TCR that confounds with the performance evaluation?<br /> - Most of the models being compared were trained on general proteins rather than TCR sequences. This makes their comparison to catELMO questionable since it's not clear if the improvement is due to the training data or architecture. The authors partially addressed this with BERT-based models in section 2.4. This concern would be more fully addressed if the authors also trained the Doc2vec model (Yang et al, Figure 2) on TCR sequences as baseline models instead of using the original models trained on general protein sequences. This would make clear the strength of context-aware embeddings if the performance is worse than catElmo and BERT.

    1. Reviewer #3 (Public Review):

      The study aims at creating novel episodic memories during slow wave sleep, that can be transferred in the awake state. To do so, participants were simultaneously presented during sleep both foreign words and their arbitrary translations in their language (one word in each ear), or as a control condition only the foreign word alone, binaurally. Stimuli were presented either at the trough or the peak of the slow oscillation using a closed-loop stimulation algorithm. To test for the creation of a flexible association during sleep, participant were then presented at wake with the foreign words alone and had (1) to decide whether they had the feeling of having heard that word before, (2) to attribute this word to one out of three possible conceptual categories (to which translations word actually belong), and (3) to rate their confidence about their decision.

      The paper is well written, the protocol ingenious and the methods are robust. However, the results do not really add conceptually to a prior publication of this group showing the possibility to associate in slow wave sleep pairs of words denoting large or small object and non words, and then asking during ensuing wakefulness participant to categorise these non words to a "large" or "small" category. In both cases, the main finding is that this type of association can be formed during slow wave sleep if presented at the trough (versus the peak) of the slow oscillation. Crucially, whether these associations truly represent episodic memory formation during sleep, as claimed by the authors, is highly disputable as there is no control condition allowing to exclude the alternative, simpler hypothesis that mere perceptual associations between two elements (foreign word and translation) have been created and stored during sleep (which is already in itself an interesting finding). In this latter case, it would be only during the awake state when the foreign word is presented that its presentation would implicitly recall the associated translation, which in turn would "ignite" the associative/semantic association process eventually leading to the observed categorisation bias (i.e., foreign words tending to be put in the same conceptual category than their associated translation). In the absence of a dis-confirmation of this alternative and more economical hypothesis, and if we follow Ocam's razor assumption, the claim that there is episodic memory formation during sleep is speculative and unsupported, which is a serious limitation irrespective of the merits of the study. The title and interpretations should be toned down in this respect

      Other remarks:

      Lines 43-45 : the assumption that the sleeping brain decides whether external events can be disregarded, requires awakening or should be stored for further consideration in the waking state is dubious, and the supporting references date from a time (the 60') during which hypnopedia was investigated in badly controlled sleep conditions (leaving open the doubt about the possibility that it occurred during micro awakenings)

      1st paragraph, lines 48-53 , the authors should be more specific about what kind of new associations and at which level they can be stored during sleep according to recent reports, as a wide variety of associations (mostly elementary levels) are shown in the cited references. Limitations in information processing during sleep should also be acknowledged.

      The authors ran their main behavioural analyses on delayed retrieval at 36h rather than 12h with the argument that retrieval performance was numerically larger at 36 than 12h but the difference was non-significant (line 181-183), and that effects were essentially similar. Looking at Figure 2, is the trough effect really significant at 12h ? In any case, the fact that it is (numerically) higher at 36 than 12h might suggest that the association created at the first 12h retrieval (considering the alternative hypothesis proposed above) has been reinforced by subsequent sleep.

      In the discussion section lines 419-427, the argument is somehow circular in claiming episodic memory mechanisms based on functional neuroanatomical elements that are not tested here, and the supporting studies conducted during sleep were in a different setting (e.g. TMR)

      Supplementary Material: in the EEG data the differentiation between correct and incorrect ulterior classifications when presented at the peak of the slow oscillation is only significant in association with 36h delayed retrieval but not at 12h, how do the authors explain this lack of effect at 12 hour?

    1. Reviewer #3 (Public Review):

      SOCE is a ubiquitous cell signalling pathway that sustains long-lasting Ca2+ elevations required for the proliferation of T cells and the differentiation and contractility of skeletal muscle. Patients with loss of function mutations in either STIM1 or ORAI1 suffer from severe combined immunodeficiency while patients with gain-of-function mutations suffer from muscle weakness. The report that an intracellular calcium channel acts as a tether at membrane contact sites to regulate the activity of STIM/ORAI channels is thus relevant for health and disease, given the essential role of the SOCE pathway for immune and muscle cell function.

      The IP3R is the major Ca2+ release pathway that initiates the STIM/ORAI activation cascade and the group of Colin Taylor (coauthor of the present study) showed that a pool of immobile receptors licensed to respond to physiological stimuli localizes near STIM-ORAI interaction sites at ER-PM junctions DOI: 10.1016/j.ceb.2018.10.001. This group further showed that IP3Rs are tethered to PM-bound actin by the KRas-induced actin-interacting protein (KRAP) DOI: 10.1038/s41467-021-24739-9 while the group of Indu Ambudkar showed that IP3R is juxtaposed to immobile STIM2 clusters within ER-PM junctions DOI: https://doi.org/10.1073/pnas.2114928118 The mechanism by which IP3R impinges on SOCE at ER-PM contact sites remains unclear, however.

      The present study provides an important clue by showing that IP3Rs themselves can act as tethering proteins independently of their calcium release function. However, several important questions remain unanswered. Are the native and mutated receptors recruited differentially to ER-PM junctions? If so, what interacting partner(s) and mechanisms enable IP3-bound receptors to enhance the interactions between STIM1 and ORAI1? And why is this effect restricted to neuronal cells?

      Previous studies indicate that IP3R can interact with actin via KRAP, with STIM proteins, with ORAI channels, and with phosphoinositides. The authors point to phosphoinositides as a potential target that could explain the need for IP3, but this possibility has not been experimentally addressed. They should establish whether phosphoinositides are involved in the recruitment of IP3R receptors and provide additional mechanistic insight by documenting whether IP3R depletion impacts the stability of contact sites or their ability to exchange lipids between membranes. Another unresolved question relates to the observation that the phenotype is restricted to neuronal cell types and absent in HEK-293 cells typically used for electrophysiological recordings of CRAC currents. The authors should attempt to clarify the molecular basis of this difference between cell types.

      From a methodological standpoint, one limitation is that the functional assays used are quite indirect. One critical SOCE determinant is the filling state of intracellular calcium stores, which was estimated indirectly by measuring the amplitude of the Ca2+ elevation evoked by the addition of the SERCA inhibitor thapsigargin. Although this method is widely used it does not directly reflect the key parameter driving STIM1 activation which is the free calcium concentration within the ER lumen. Direct ER [Ca2+] recordings are required to clarify this critical point.

    1. Reviewer #3 (Public Review):

      Summary of Author's Results/Intended Achievements<br /> The authors were trying to ascertain the underlying learning mechanisms and network structure that could explain their primary experimental finding: passive exposure to a stimulus (independent of when the exposure occurs) can lead to improvements in active (supervised) learning. They modeled their task with 5 progressively more complex shallow neural networks classifying vectors drawn from multi-variate Gaussian distributions.

      Account of Major Strengths:<br /> Overall, the experimental findings were interesting, albeit not necessarily novel. The modelling was also appropriate, with a solid attempt at matching the experimental condition to simplified network models.

      Account of Major Weaknesses:<br /> I would say there are two major weaknesses of this work. The first is that even Model 5 differs from their data. For example, the A+P (passive interleaved condition) learning curve in Figure 7 seems to be non-monotonic, and has some sort of complex eigenvalue in its decay to the steady state performance as trials increase. This wasn't present in their experimental data (Figure 2D), and implies a subtle but important difference. There also appear to be differences in how quickly the initial learning (during early trials) occurs for the A+P and A:P conditions. While both A+P and A:P conditions learn faster than A only in M5, A+P and A:P seem to learn in different ways, which isn't supported in their data. The second major weakness is that the authors also don't generate any predictions with M5. Can they test this model of learning somehow in follow-up behavioural experiments in mice?

      Discussion of Likely Impact:<br /> Without follow-up experiments to test their mechanism of why passive exposure helps in a schedule-independent way, the impact of this paper will be limited.

      Additional Context:<br /> I believe the authors need to place this work in the context of a large amount of existing literature on passive (unsupervised) and active (supervised) learning interactions. This field is broad both experimentally and computationally. For example, there is an entire sub-field of machine learning, called semi-supervised learning that is not mentioned at all in this work.

    1. Reviewer #3 (Public Review):

      This study investigates the hypothesis that humans (but not non-human primates) spontaneously learn reversible temporal associations (i.e., learning a B-A association after only being exposed to A-B sequences), which the authors consider to be a foundational property of symbolic cognition. To do so, they expose humans and macaques to 2-item sequences (in a visual-auditory experiment, pairs of images and spoken nonwords, and in a visual-visual experiment, pairs of images and abstract geometric shapes) in a fixed temporal order, then measure the brain response during a test phase to congruent vs. incongruent pairs (relative to the trained associations) in canonical vs. reversed order (relative to the presentation order used in training). The advantage of neuroimaging for this question is that it removes the need for a behavioral test, which non-human primates can fail for reasons unrelated to the cognitive construct being investigated. In humans, the researchers find statistically indistinguishable incongruity effects in both directions (supporting a spontaneous reversible association), whereas in monkeys they only find incongruity effects in the canonical direction (supporting an association but a lack of spontaneous reversal). Although the precise pattern of activation varies by experiment type (visual-auditory vs. visual-visual) in both species, the authors point out that some of the regions involved are also those that are most anatomically different between humans and other primates. The authors interpret their finding to support the hypothesis that reversible associations, and by extension symbolic cognition, is uniquely human.

      This study is a valuable complement to prior behavioral work on this question. However, I have some concerns about methods and framing.

      Methods - Design issues:

      1. The authors originally planned to use the same training/testing protocol for both species but the monkeys did not learn anything, so they dramatically increased the amount of training and evaluation. By my calculation from the methods section, humans were trained on 96 trials and tested on 176, whereas the monkeys got an additional 3,840 training trials and 1,408 testing trials. The authors are explicit that they continued training the monkeys until they got a congruity effect. On the one hand, it is commendable that they are honest about this in their write-up, given that this detail could easily be framed as deliberate after the fact. On the other hand, it is still a form of p-hacking, given that it's critical for their result that the monkeys learn the canonical association (otherwise, the critical comparison to the non-canonical association is meaningless).

      2. Between-species comparisons are challenging. In addition to having differences in their DNA, human participants have spent many years living in a very different culture than that of NHPs, including years of formal education. As a result, attributing the observed differences to biology is challenging. One approach that has been adopted in some past studies is to examine either young children or adults from cultures that don't have formal educational structures. This is not the approach the authors take. This major confound needs to minimally be explicitly acknowledged up front.

      3. Humans have big advantages in processing and discriminating spoken stimuli and associating them with visual stimuli (after all, this is what words are in spoken human languages). Experiment 2 ameliorates these concerns to some degree, but still, it is difficult to attribute the failure of NHPs to show reversible associations in Experiment 1 to cognitive differences rather than the relative importance of sound string to meaning associations in the human vs. NHP experiences.

      4. More minor: The localizer task (math sentences vs. other sentences) makes sense for math but seems to make less sense for language: why would a language region respond more to sentences that don't describe math vs. ones that do?

      Methods - Analysis issues:

      5. The analyses appear to "double dip" by using the same data to define the clusters and to statistically test the average cluster activation (Kriegeskorte et al., 2009). The resulting effect sizes are therefore likely inflated, and the p-values are anticonservative.

      Framing:

      6. The framing ("Brain mechanisms of reversible symbolic reference: A potential singularity of the human brain") is bigger than the finding (monkeys don't spontaneously reverse a temporal association but humans do). The title and discussion are full of buzzy terms ("brain mechanisms", "symbolic", and "singularity") that are only connected to the experiments by a debatable chain of assumptions.

      First, this study shows relatively little about brain "mechanisms" of reversible symbolic associations, which implies insights into how these associations are learned, recognized, and represented. But we're only given standard fMRI analyses that are quite inconsistent across similar experimental paradigms, with purely suggestive connections between these spatial patterns and prior work on comparative brain anatomy.

      Second, it's not clear what the relationship is between symbolic cognition and a propensity to spontaneously reverse a temporal association. Certainly, if there are inter-species differences in learning preferences this is important to know about, but why is this construed as a difference in the presence or absence of symbols? Because the associations aren't used in any downstream computation, there is not even any way for participants to know which is the sign and which is the signified: these are merely labels imposed by the researchers on a sequential task.

      Third, the word "singularity" is both problematically ambiguous and not well supported by the results. "Singularity" is a highly loaded word that the authors are simply using to mean "that which is uniquely human". Rather than picking a term with diverse technical meanings across fields and then trying to restrict the definition, it would be better to use a different term. Furthermore, even under the stated definition, this study performed a single pairwise comparison between humans and one other species (macaques), so it is a stretch to then conclude (or insinuate) that the "singularity" has been found (see also pt. 2 above).

      7. Related to pt. 6, there is circularity in the framing whereby the authors say they are setting out to find out what is uniquely human, hypothesizing that the uniquely human thing is symbols, and then selecting a defining trait of symbols (spontaneous reversible association) *because* it seems to be uniquely human (see e.g., "Several studies previously found behavioral evidence for a uniquely human ability to spontaneously reverse a learned association (Imai et al., 2021; Kojima, 1984; Lipkens et al., 1988; Medam et al., 2016; Sidman et al., 1982), and such reversibility was therefore proposed as a defining feature of symbol representation reference (Deacon, 1998; Kabdebon and Dehaene-Lambertz, 2019; Nieder, 2009).", line 335). They can't have it both ways. Either "symbol" is an independently motivated construct whose presence can be independently tested in humans and other species, or it is by fiat synonymous with the "singularity". This circularity can be broken by a more modest framing that focuses on the core research question (e.g., "What is uniquely human? One possibility is spontaneous reversal of temporal associations.") and then connects (speculatively) to the bigger conceptual landscape in the discussion ("Spontaneous reversal of temporal associations may be a core ability underlying the acquisition of mental symbols").

    1. Reviewer #3 (Public Review):

      In this manuscript, Chang et al set out to find direct interactions with the Eph-B2 receptor, as our knowledge of its function/regulation is still incomplete. Using proteomic analysis of Hela cells expressing EPHB2, they identified MYCBP2 as a potential binder, which they then confirm using extensive biochemical analyses, an interaction that seems to be negatively affected by the binding of ephrin-B2 (but not B1). Furthermore, they find that FBXO45, a known MYCBP2 interaction, strongly facilitates its binding to EPHB2. Intriguingly, these interactions depend on the extracellular domains of EPHB2, something that is surprising given the fact that MYCBP2 is an intracellular protein. Finally, they find that, in contrast to what could be expected given the known function of MYCBP2 as a ubiquitin E3 ligase, it actually positively regulates EPHB2 protein stability, and function.

      The strength of this manuscript is the extensive biochemical analysis of the EPHB2/MYCBP2/FBXO43 interactions. Most of the conclusions are warranted although I do not understand the physiological interpretation of how these proteins could interact in the extracellular space.

      The attempt to extend the study to an in vivo animal using the worm is important. However, I find the results in the worm confusing and overly interpreted in their current form.

    1. Reviewer #3 (Public Review):

      Dux (or DUX4 in human) is a master transcription factor regulating early embryonic gene activation and has garnered much attention also for its involvement in reprogramming pluripotent embryonic stem cells to totipotent "2C-like" cells. The presented work starts with the recognition that DUX contains five conserved c. 100-amino acid carboxy-terminal repeats (called C1-C5) in the murine protein but not in that of other mammals (e.g. human DUX4). Using state-of-the-art techniques and cell models (BioID, Cut&Tag; rescue experiments and functional reporter assays in ESCs), the authors dissect the activity of each repeat, concluding that repeats C3 and C5 possess the strongest transactivation potential in synergy with a short C-terminal 14 AA acidic motif. In agreement with these findings, the authors find that full-length and active (C3) repeat containing Dux leads to increased chromatin accessibility and active histone mark (H3K9Ac) signals at genomic Dux binding sites. A further significant conclusion of this mutational analysis is the proposal that the weakly activating repeats C2 and C4 may function as attenuators of C3+C5-driven activity.

      By next pulling down and identifying proteins bound to Dux (or its repeat-deleted derivatives) using BioID-LC/MS/MS, the authors find a significant number of interactors, notably chromatin remodellers (SMARCC1), a histone chaperone (CHAF1A/p150) and transcription factors previously (ZSCAN4D) implicated in embryonic gene activation.

      The experiments are of high quality, with appropriate controls, and thus provide a rich compendium of Dux interactors for future study. Indeed, a number of these (SMARCC1, SMCHD1, ZSCAN4) make biological sense, both for embryonic genome activation and for FSHD (SMCHD1).

      The central question raised by this study, however, concerns the function of the Dux repeats, apparently unique to mice. While it is possible, as the authors propose, that the weak activating C1, C2 C4 repeats may exert an attenuating function ("sub-functionalization") on activation mediated by C3 and/or C5, it could similarly be argued that the different repeats are indeed expected to display different activation potentials, chromatin opening, cofactor recruitment, due to, simply, the differences in their sequences. The argument for an active attenuating function would have been strengthened, for example, by the finding of repressor recruitment by C1/C2/C4 (and not just less of everything). The possible biological relevance of these repeats thus remains to be established.

    1. Reviewer #3 (Public Review):

      Peng et al. designed a computational framework for identifying pioneer factors using epigenomic data from five cell types. The identification of pioneer factors is important for our understanding of the epigenetic and transcriptional regulation of cells. A computational approach toward this goal can significantly reduce the burden of labor-intensive experimental validation. Nevertheless, there are several caveats in the current analysis which may require some modification of the computational methods and additional analysis to maximize the confidence of the pioneer factor prediction results.

      A key consideration that arises during this review is that the current analysis anchors on H1 ESC and therefore may have biased the results toward the identification of pioneer factors that are relevant to the four other differentiated cell types. The low ranking of Yamanaka factors and known pioneer factors of NFYs and ESRRB may be due to the setup of the computational framework. Analysis should be repeated by using each of every cell type as an anchor for validating the reproducibility of the pioneer factors found so far and also to investigate whether TFs related to ESC identity (e.g. Yamanaka factors, NFYs and ESRRB) would show significant changes in their ranking. Given the potential cell type specificity of the pioneer factors, the extension to more cell types appears to be important for further demonstrating the utility of the computational framework.

    1. Reviewer #3 (Public Review):

      This paper combines experiments and simple modeling to try to identify the relationship between external muscle torque vs. a stimulus burst duration on several leg muscles of a stick insect. The authors created a setup to input PWM and voltage values and measured the output torque through load cells. They found an appropriate model for estimating muscle torque through different PWM burst durations and voltage values by comparing WAIC values for each modeling equation. They found that the linear hierarchical model relating burst duration and joint torque and a nonlinear hierarchical model relating burst duration and joint torque to a power function represent the muscle torque activation the best.

      The problem that the study tries to address is of great importance to the field of cyborg, biomechanics, neuromechanics, mechano-sensing, and animal locomotion (see below). There have been very few studies that tried to quantify how muscle activation in invertebrates affects force/torque output, which is important for understanding the dynamics of their movement, and this is one of the first to investigate this. The approach is technically sound, and the experimental data and modeling analyses are solid and support the conclusions drawn.

    1. Reviewer #3 (Public Review):

      In this manuscript, Castano et al generate and test a small molecule inhibitor of CDKL5, an X-linked kinase whose loss-of-function is the cause of a severe neurodevelopmental disorder. Since the current knowledge of CDKL5 functions mainly rely on genetic models it is still unclear which effects are caused directly by CDKL5 loss and which can be ascribed to indirect effects. A specific inhibitor would therefore be an important tool for the field.

      Castano and colleagues therefore tested a panel of twenty kinase inhibitors for their capacity to block phosphorylation of a EB2, a bona fide CDKL5 substrate, in rat neurons. Among the three that could inhibit EB2 phosphorylation at low concentrations, one was found to inhibit CDKL5 while not affecting GSK3 kinases, which share significant homology to CDKL5. Considering that genetic studies have previously linked CDKL5 to excitatory synaptic transmission, acute hippocampal slices were exploited to test the consequences of CDKL5 inhibition. While CDKL5 loss in the past was found to affect both AMPA- and NMDA-Rs, the small molecule-based inhibition affected only AMPA-R responses at the post-synaptic level. Since pharmacokinetic analyses showed that the inhibitor has a low capacity for brain penetration the molecule remains limited for testing the acute inhibition of CDKL5 in vitro and ex vivo. Such a tool represents an important aspect in the CDKL5 field and the findings suggesting a direct role of CDKL5 in regulating AMPA-R functions are interesting. However, the manuscript could be improved to render it more readable.

      The description of the binding and orthogonal assays, which are the basis for the selection of the small molecule inhibitor, is not straightforward to understand for non-expert readers and could be improved.

      While the in vitro and ex vivo assays are well presented, it is not clear why the myelin basic protein is used as a substrate for CDKL5 in the in vitro kinase assays. Does this protein contain a CDKL5 consensus site?

    1. Reviewer #3 (Public Review):

      The present manuscript describes a new method to identify the emitter of ultrasonic vocalisations during social interactions between 2 or 3 mice. The method combines two technologies (an "acoustic camera" and a set of four microphones) and succeeds in increasing the spatial precision and the attribution of USV emission to one of the mice. The manuscript describes the characteristics and advantages of each method and the advantages of using both to optimize the identification of USV emitter. The authors used the method to confirm that females are also vocalising during male-female interactions and that females emit USV mostly during nose-nose contact while this was not the case for males. Interestingly, the authors identified that the vocal behaviour of two competing males was strongly asymmetric when facing a female. This was not the case for two females facing one male.

      The method is really promising since the identification of the emitter of USVs during mouse social interactions is a necessary step to speed up our understanding of this communication modality. The increase in spatial precision and in the proportion of attributed vocalisations is non-negligible and will be of great utility in the future.

      Generally, the statistical analyses should be adjusted. Indeed, the statistical analyses do not consider the fact that the same individuals were recorded several times (if we understood well the methods). Each point was considered independent (in non-parametric Wilcoxon tests), while this is not the case given the repetitions with the same individuals (the number of repeated encounters per individual should be given in the methods section, by the way). We strongly recommend revising the statistical analyses of the results in Figures 4 and 5. In addition, it could be interesting to check whether the vocal behaviour is stable within each individual (i.e., a male that is vocalising frequently in one situation vocalises always frequently in other situations).

      It is not easy to understand the rationale behind testing animals in pairs and in triads from the beginning of the manuscript. The authors should better introduce this aspect in the manuscript, especially given the fact that biological results deal with this aspect in Figure 5. The authors might strengthen the parts on the biological results extracted from their new method.

      More specifically, the fact that one male takes over the vocal behaviour within a triad is of high interest. Nevertheless, some behavioural data would be needed to strengthen these findings.

      A small proportion of USVs was not assigned. The authors did not discuss the potential reason for this failure (Were the USVs too soft? Did they include specific acoustic characteristics that render them difficult to localise?). These points could be of interest when testing other mouse strains or other species.

    1. Reviewer #3 (Public Review):

      In this manuscript, Castano et al generate and test a small molecule inhibitor of CDKL5, an X-linked kinase whose loss-of-function is the cause of a severe neurodevelopmental disorder. Since the current knowledge of CDKL5 functions mainly rely on genetic models it is still unclear which effects are caused directly by CDKL5 loss and which can be ascribed to indirect effects. A specific inhibitor would therefore be an important tool for the field.

      Castano and colleagues therefore tested a panel of twenty kinase inhibitors for their capacity to block phosphorylation of a EB2, a bona fide CDKL5 substrate, in rat neurons. Among the three that could inhibit EB2 phosphorylation at low concentrations, one was found to inhibit CDKL5 while not affecting GSK3 kinases, which share significant homology to CDKL5. Considering that genetic studies have previously linked CDKL5 to excitatory synaptic transmission, acute hippocampal slices were exploited to test the consequences of CDKL5 inhibition. While CDKL5 loss in the past was found to affect both AMPA- and NMDA-Rs, the small molecule-based inhibition affected only AMPA-R responses at the post-synaptic level. Since pharmacokinetic analyses showed that the inhibitor has a low capacity for brain penetration the molecule remains limited for testing the acute inhibition of CDKL5 in vitro and ex vivo. Such a tool represents an important aspect in the CDKL5 field and the findings suggesting a direct role of CDKL5 in regulating AMPA-R functions are interesting. However, the manuscript could be improved to render it more readable.

      The description of the binding and orthogonal assays, which are the basis for the selection of the small molecule inhibitor, is not straightforward to understand for non-expert readers and could be improved.

      While the in vitro and ex vivo assays are well presented, it is not clear why the myelin basic protein is used as a substrate for CDKL5 in the in vitro kinase assays. Does this protein contain a CDKL5 consensus site?

    1. Reviewer #3 (Public Review):

      The paper by Li et al. describes the role of the TOR pathway in Aspergillus flavus. The authors tested the effect of rapamycin in WT and different deletion strains. This paper is based on a lot of experiments and work but remains rather descriptive and confirms the results obtained in other fungi. It shows that the TOR pathway is involved in conidiation, aflatoxin production, pathogenicity, and hyphal growth. This is inferred from rapamycin treatment and TOR1/2 deletions. Rapamycin treatment also causes lipid accumulation in hyphae. The phenotypes are not surprising as they have been shown already for several fungi. In addition, one caveat is in my opinion that the strains grow very slowly and this could cause many downstream effects. Several kinases and phosphatases are involved in the TOR pathway. They were known from S. cerevisiae or filamentous fungi. The authors characterized them as well with knock-out approaches.

      As for many results, I miss the re-complementation of the created mutants throughout the manuscript. This is standard praxis.

      Fig. 1: cultures were grown for 48 h before measuring the transcript level. The authors show that brlA, abaA, and some sexual regulators are less expressed. In my opinion, this does not allow the conclusion that there is a direct control through rapamycin. Since the colonies grow very slowly in the presence of rapamycin, the authors should add rapamycin and follow gene expression after 15, 30, 60, 90 min. The figure legend needs to be more detailed. Which type of cultures were used, liquid, solid medium? Etc.

      Why in chapter one Fig. 9 is already cited? Those data should then be included in Fig. 1 for the general phenotype.

      The authors wrote that radial growth and conidiation were gradually reduced with increasing rapamycin concentrations. This is not true. There is no gradient! However, it should be tested if there is a gradient if lower concentrations are used. The current data imply that there is a threshold concentration, so either there is 100 % growth or a reduction to 25 %. This looks strange.

    1. Reviewer #3 (Public Review):

      In this work, Kita et al., aim to understand the activation mechanisms of the kinesin-3 motors KLP-6 and UNC-104 from C. elegans. As with many other motor proteins involved in intracellular transport processes, KLP-6 and UNC-104 motors suppress their ATPase activities in the absence of cargo molecules. Relieving the autoinhibition is thus a crucial step that initiates the directional transport of intracellular cargo. To investigate the activation mechanisms, the authors make use of mass photometry to determine the oligomeric states of the full-length KLP-6 and the truncated UNC-104(1-653) motors at sub-micromolar concentrations. While full-length KLP-6 remains monomeric, the truncated UNC-104(1-653) displays a sub-population of dimeric motors that is much more pronounced at high concentrations, suggesting a monomer-to-dimer conversion. The authors push this equilibrium towards dimeric UNC-104(1-653) motors solely by introducing a point mutation into the coiled-coil domain and ultimately unleashing a robust processivity of the UNC-104 dimer. The authors find that the same mechanistic concept does not apply to the KLP-6 kinesin-3 motor, suggesting an alternative activation mechanism of the KLP-6 that remains to be resolved. The present study encourages further dissection of the kinesin-3 motors with the goal of uncovering the main factors needed to overcome the 'self-inflicted' deactivation.

    1. Reviewer #3 (Public Review):

      This is an interesting and carefully done study that will be of considerable value to the field of cortical interneurons. The main result is the development of a novel intersectional genetic strategy to identify and manipulate neurogliaform cells (NGFCs), an interneuron subtype that has been somewhat under-explored to date (but perhaps not quite as enigmatic as implied by the authors). The new strategy, using Id2-CreER transgenic mice crossed with a pan-interneuronal Flp line, appears to label all interneurons which do not express PV, Sst, or VIP, and thus defines a fourth subclass of interneurons. The main members of this subclass are NPY-expressing NGFCs. The strategy allows the targeting of NGFCs in all cortical layers, in contrast to previous strategies using the NDNF-Cre mice which target mostly Layer 1 NGFCs (and possibly also other Layer 1 subtypes). The same strategy also labels a relatively small population of non-NGF Id2 cells belonging to the CCK-expressing subtype(s).

      In the first stage of the study, the authors characterize the labeled neurons by their expression of protein markers (most notably NPY and CCK), by their dendritic and axonal morphology, and by their electrophysiological properties. This characterization is detailed and rigorous and the observed characteristics are consistent with what is already known about the properties of NGFCs. The weaknesses here are that the morphological features are not analyzed quantitatively, the definition of electrophysiological subtypes remains somewhat subjective, and the authors do not attempt a multivariate analysis that could provide a data-driven parcellation into subtypes.

      The authors then go two steps further. First, they use ex-vivo recordings to demonstrate that presumed CCK+ neurons (identified by their firing pattern as "non-late-spiking), but not NGFCs (identified by their "late-spiking" phenotype), are sensitive to endocannabinoids released from postsynaptic pyramidal cells upon depolarization of the latter. This DSI ("depolarization suppression of inhibition") is a well-studied property of hippocampal CCK+ basket cells, so its demonstration adds to the validation of the intersectional strategy in targeting this subtype in the neocortex. Somewhat surprisingly, the authors do not attempt to demonstrate in their ex-vivo experiments what may be the best-known property of NGFCs - their propensity to preferentially activate GABAB receptors.

      The authors then perform in-vivo silicon probe recordings in which Id2 cells are "optotagged" with ChR2 and can thus be identified in extracellular recordings. These in-vivo recordings are probably the first ever from identified NGFCs below layer 1, although some uncertainty remains about the identification of optotagged cells as NGFCs vs CCK-expressing interneurons. They find several differences between firing patterns of NGFCs and other interneurons or pyramidal cells (identified by their extracellular spike waveforms), the most dramatic being a pronounced "rebound" of NGFC firing during slow-wave sleep immediately after a DOWN-to-UP state transition. While the functional significance of these findings is not clear, these experiments provide proof of concept that this fourth (and last?) interneuron subclass can be identified, recorded, and manipulated in freely behaving animals.

      In summary, while adding only modestly to our knowledge of NGFCs and CCK-expressing interneurons per se, this work provides an important new tool that will no doubt be used in future studies to target cortical NGFCs and CCK interneurons for in-vivo and ex-vivo recordings, for optogenetic manipulations and for calcium or voltage imaging using genetically-encoded probes. In this sense, the current study is a breakthrough into what may truly be "the last frontier" of cortical interneurons.

    1. Reviewer #3 (Public Review):

      Overview: The authors propose a personalized ventricular computational model (Geno-DT) that incorporates the patient's structural remodeling (fibrosis and scar locations based on LGE-CMR scans) as well as genotyping (cell membrane kinetics based on genetic testing results) to predict VT locations and morphologies in ARVC setting.<br /> To test the model, the authors conducted a retrospective study using 16 ARVC patient data with two genotypes (PKP2, GE) and reported high degree of sensitivity, specificity, and accuracy. In addition, the authors determined that in GE patients, VT was driven by fibrotic remodeling, whereas, in PKP2 patients, VT was associated with a combination of structural and electrical remodeling (slowed conduction and altered restitution).<br /> Based on the findings, the authors recommend using Geno-DT approach to augment therapeutic accuracy in treatment of ARVC patients.

      Critiques:

      1. The small sample size is a limitation but has already been acknowledged and documented by the authors.

      2. Another limitation is the consideration of only two of the possible genotypes in developing the cell membrane kinetics, but again has been acknowledged by the authors.

      Final Thoughts: The authors have done a commendable job in targeting a disease phenotype that is relatively rare, which constrains the type of data that can be collected for research. Their personalized computational model approach makes a valuable contribution to furthering our understanding of ARVC mechanisms.

    1. Reviewer #3 (Public Review):

      Two studies published in 2020 independently identified the alPg, pC1d, and pC1e neurons to be involved in initiating and maintaining a state of aggression in female Drosophila. Both studies combined behavioural analyses, optogenitic manipulation of neurons, and connectomics. One of these studies proposed that the extensive interconnections seen between the alPg and pC1d+e neurons might represent a recurrent motif known to support persistent behvioural states in other systems. In this manuscript, the authors test this idea and report that their data do not support it. Specifically, they report that alPg or pC1d+e (but not pC1d alone) can initiate a persistent state of aggression. But they find that the persistent aggressive state is maintained even when the pC1d neurons are inactivated. Finally, they show that neither of these neurons themselves sustains neuronal activity upon stimulation, nor do either of them induce a persistent activity in the other. Together, their data suggest that the recurrent connection between alPg and pC1d is not what supports the persistent state. The data underlying these claims are convincing. A possibility to explore before ruling out recurrent motifs (at this circuit level) in maintaining aggression is that the connections between alPg and pC1e can compensate for the loss of pC1e. Overall, the study is important and will be of interest to those who study the circuit basis of persistent behavioural states, but also to neuroscientists in general.

    1. Reviewer #3 (Public Review):

      This study addresses the major question of 'whether and when grid cells contribute to behavior'. There is no doubt that this is a very important question. My major concern is that I'm not convinced that this study gives a significant contribution to this question, although this study is well-performed and potentially interesting. This is mainly due to the fact that the relation between grid cell properties and behavior is exclusively correlative and entirely based on single cell activity, although the introduction mentions quite often the grid cell network properties and dynamics. In general, this study gives the impression that grid cells exclusively support the cognitive processes involved in this task. This problem is in part related to the text. However, it would be interesting to look at the population level (even beyond grid cells) to test whether at the network level, the link between behavioral performance and neural activity is more straightforward compared to the single-cell level. This approach could reconcile the present results with those obtained in their previous study following MEC inactivation.

      The authors used a statistical method based on the computation of the frequency spectrum of the spatial periodicity of the neural firing to classify grid cells as 'position-coding' (with fields anchored to the virtual track) and 'distance-coding' (with fields repeating at regular intervals across trials). This is an interesting approach that has nonetheless the default to be based exclusively on autocorelograms. It would be interesting to compare with a different method based on the similarities between raw maps. Beyond this minor point, cell categorization is performed using all trial types. Each trial type (i.e. beacon or non-beacon) is supposed to force mice to use different strategies and should induce different spatial representations within the entorhinal-hippocampal circuit (and not only in the grid cell system). In that context, since all trials are mixed, it is difficult to extrapolate general information. On page 5 the authors state that 'Since only position representations should reliably predict the reward location, ..., we reasoned that the presence of positional coding could be used to assess whether grid firing contributes to the ongoing behaviour'.

      I do not agree with this statement. First of all, position coding should be more informative only in a cue-guided trial. Second, distance coding could be as informative as position coding since at the network level may provide information relevant to the task (such as distance from the reward). This possibility is not tested here. Third, position-coding is interpreted as more relevant because it predominates in correct trials. However, this does not imply that this coding scheme is indeed used to perform correct trials. It could be more informative to push forward the correlative analysis by looking at whether behavioral performance can be predicted by the coding scheme on a trial-by-trial basis. This analysis would not provide a causal relation between cell activity and behavior, but could strengthen the correlation between the two.

    1. Reviewer #3 (Public Review):

      In this work, the authors shed light onto the structures of Fusarium oxysporum f.sp. lycopersici proteins involved in the infection of tomato. They unravelled several new secreted effector protein structures and additionally used computational approaches to structurally classify the remaining effectors known from this pathogen. Through this they uncovered a new and unique structural class of proteins which they found to be present and widely distributed in fungal plant pathogens and plant symbiotic fungi. The authors further predicted structural models for the full SIX effector set revealing that genome-proximal effector pairs share similar structural classes. Building on their Avr1 structure, the authors also define the C-terminal domain and specific amino acid residues that are essential to Avr1 detection by its cognate immune receptor.

      A major strength of this work is a portfolio of several (Avr1, Avr3, SIX6, SIX8) new structurally resolved proteins which led to the discovery that several of them fall into the same structural class. These findings are supported by strong results.

      The experiments addressing the structure-function relationship of Avr1's avirulence activity are highly relevant to our understanding of disease resistance mechanisms against Fusarium, but will require additional controls to allow for solid conclusions to be drawn. In particular, it needs to be demonstrated that specific I gene alleles are at all required for FonSIX4's cell death activity in N.benthamiana leaves or whether FonSIX4 and those of some chimeric proteins is independent of the tomato I receptor. Complementary work in Fusarium mutants lacking Avr1 and expressing chimeric versions would document that the observations from transient expressions in Nicotiana benthamiana are relevant in the biological context of a Fusarium/tomato interaction.

      The discovered solvent-exposed residues conditioning Avr1 recognition by the I receptor seem to be positioned in an area of the protein which had previously been highlighted as being highly variable in FOLD proteins of symbiotic fungi but it is not clear from the work whether this is indeed the case or whether Avr1 differs significantly in its structure from FOLD proteins found in other fungi.<br /> It also remains to be addressed whether the residues conditioning avirulence activity is also crucial for virulence activity in Fusarium?

      This work uncovered a new structural class of proteins with critical roles in plant-pathogen interactions. Structure-based predictions and genome-wide comparisons have emerged as a new approach enabling the identification of similar proteins with divergent sequences. The work undertaken by the authors adds to a growing body of work in plant-microbe research, predominantly from pathogenic organisms, and more recently in symbiotic fungi.

    1. Reviewer #3 (Public Review):

      There has been a long-standing link between the biology of sulfur-containing molecules (e.g., hydrogen sulfide gas, the amino acid cysteine, and its close relative cystine, et cetera) and the biology of hypoxia, yet we have a poor understanding of how and why these two biological processes and are co-regulated. Here, the authors use C. elegans to explore the relationship between sulfur metabolism and hypoxia, examining the regulation of cysteine dioxygenase (CDO1 in humans, CDO-1 in C. elegans), which is critical to cysteine catabolism, by the hypoxia inducible factor (HIF1 alpha in humans, HIF-1 in C. elegans), which is the key terminal effector of the hypoxia response pathway that maintains oxygen homeostasis. The authors are trying to demonstrate that (1) the hypoxia response pathway is a key regulator of cysteine homeostasis, specifically through the regulation of cysteine dioxygenase, and (2) that the pathway responds to changes in cysteine homeostasis in a mechanistically distinct way from how it responds to hypoxic stress.

      Briefly summarized here, the authors initiated this study by generating transgenic animals expressing a CDO-1::GFP protein chimera from the cdo-1 promoter so that they could identify regulators of CDO-1 expression through a forward genetic screen. This screen identified mutants with elevated CDO-1::GFP expression in two genes, egl-9 and rhy-1, whose wild-type products are negative regulators of HIF-1, raising the possibility that cdo-1 is a HIF-1 transcriptional target. Indeed, the authors provide data showing that cdo-1 regulation by EGL-9 and RHY-1 is dependent on HIF-1 and that regulation by RHY-1 is dependent on CYSL-1, as expected from other published findings of this pathway. The authors show that exogenous cysteine activates cdo-1 expression, reflective of what is known to occur in other systems. Moreover, they find that exogenous cysteine is toxic to worms lacking CYSL-1 or HIF-1 activity, but not CDO-1 activity, suggesting that HIF-1 mediates a survival response to toxic levels of cysteine and that this response requires more than just the regulation of CDO-1. The authors validate their expression studies using a GFP knockin at the cdo-1 locus, and they demonstrate that a key site of action for CDO-1 is the hypodermis. They present genetic epistasis analysis supporting a role for RHY-1, both as a regulator of HIF-1 and as a transcriptional target of HIF-1, in offsetting toxicity from aberrant sulfur metabolism. The authors use CRISPR/Cas9 editing to mutate a key amino acid in the prolyl hydroxylase domain of EGL-9, arguing that EGL-9 inhibits CDO-1 expression through a mechanism that is largely independent of the prolyl hydroxylase activity.

      Overall, the data seem rigorous, and the conclusions drawn from the data seem appropriate. The experiments test the hypothesis using logical and clever molecular genetic tools and design. The sample size is a bit lower than is typical for C. elegans papers; however, the experiments are clearly not underpowered, so this is not an issue. The paper is likely to drive many in the field (including the authors themselves) into deeper experiments on (1) how the pathway senses hypoxia and sulfur/cysteine/H2S using these distinct mechanisms/modalities, (2) how oxygen and sulfur/cysteine/H2S homeostasis influence one another, and (3) how this single pathway evolved to sense and respond to both of these stress modalities.

      Major strengths of the paper include (1) the use of the powerful whole animal C. elegans model to reveal results that have meaning in vivo, (2) the careful demonstration through mutant rescue experiments that key transgenes have functional activity, (3) the use of CRISPR/Cas9 editing to mutate a critical residue in the catalytic domain of the EGL-9 prolyl hydroxylase, (4) transgenic rescue experiments that show that CDO-1 operates in the hypodermis with regard to the larval arrest phenotype, and (5) the thorough epistatic analysis of different pathway mutants.

      Major weaknesses of the paper include (1) the over-reliance on genetic approaches, (2) the lack of novelty regarding prolyl hydroxylase-independent activities of EGL-9, and (3) the lack of biochemical approaches to probe the underlying mechanism of the prolyl hydroxylase-independent activity of EGL-9.

      Major Issues We Feel the Authors Should Address:

      1. One particularly glaring concern is that the authors really do not know the extent to which the prolyl hydroxylase activity is (or is not) impacted by the H487A mutation in egl-9(rae276). If there is a fair amount of enzymatic activity left in this mutant, then it complicates interpretation. The paper would be strengthened if the authors could show that the egl-9(rae276) eliminates most if not all prolyl hydroxylase activity. In addition, the authors may want to consider doing RNAi for egl-9 in the egl-9(rae276) mutant as a control, as this would support the claim that whatever non-hydroxylase activity EGL-9 may have is indeed the causative agent for the elevation of CDO-1::GFP. Without such experiments, readers are left with the nagging concern that this allele is simply a hypomorph for the single biochemical activity of EGL-9 (i.e., the prolyl hydroxylase activity) rather than the more interesting, hypothesized scenario that EGL-9 has multiple biochemical activities, only one of which is the prolyl hydroxylase activity.

      2. The authors observed that EGL-9 can inhibit HIF-1 and the expression of the HIF-1 target cdo-1 through a combination of activities that are (1) dependent on its prolyl hydroxylase activity (and subsequent VHL-1 activity that acts on the resulting hydroxylated prolines on HIF-1), and (2) independent of that activity. This is not a novel finding, as the authors themselves carefully note in their Discussion section, as this odd phenomenon has been observed for many HIF-1 target genes in multiple publications. While this manuscript adds to the description of this phenomenon, it does not really probe the underlying mechanism or shed light on how EGL-9 has these dual activities. This limits the overall impact and novelty of the paper.

      3. Cysteine dioxygenases like CDO-1 operate in an oxygen-dependent manner to generate sulfites from cysteine. CDO-1 activity is dependent upon availability of molecular oxygen; this is an unexpected characteristic of a HIF-1 target, as its very activation is dependent on low molecular oxygen. Authors neither address this in the text nor experimentally, and it seems a glaring omission.

      4. The authors determined that the hypodermis is the site of the most prominent CDO-1::GFP expression, relevant to Figure 4. This claim would be strengthened if a negative control tissue, in the animal with the knockin allele, were shown. The hypodermal specific expression is a highlight of this paper, so it would make this article even stronger if they could further substantiate this claim.

      Minor issues to note:

      Mutants for hif-1 and cysl-1 are sensitive to exogenous cysteine levels, yet loss of CDO-1 expression is not sufficient to explain this phenomenon, suggesting other targets of HIF-1 are involved. Given the findings the authors (and others) have had showing a role for RHY-1 in sulfur amino acid metabolism, shouldn't the authors consider testing rhy-1 mutants for sensitivity to exogenous cysteine?

      The cysteine exposure assay was performed by incubating nematodes overnight in liquid M9 media containing OP50 culture. The liquid culture approach adds two complications: (1) the worms are arguably starving or at least undernourished compared to animals grown on NGM plates, and (2) the worms are probably mildly hypoxic in the liquid cultures, which complicates the interpretation.

      An easily addressable concern is the wording of one of the main conclusions: that cdo-1 transcription is independent of the canonical prolyl hydroxylase function of EGL-9 and is instead dependent on one of EGL-9's non-canonical, non-characterized functions. There are several points in which the wording suggests that CDO-1 toxicity is independent of EGL-9. In their defense, the authors try to avoid this by saying, "EGL-9 PHD," to indicate that it is the prolyl hydroxylase function of EGL-9 that is not required for CDO-1 toxicity. However, this becomes confusing because much of the field uses PHD and EGL-9/EGLN as interchangeable protein names. The authors need to be clear about when they are describing the prolyl hydroxylase activity of EGL-9 rather than other (hypothesized) activities of EGL-9 that are independent of the prolyl hydroxylase activity.

      The authors state in the text, "the egl-9; suox-1 double mutants are extremely sick and slow growing." We appreciate that their "health" assay, based on the exhaustion of food from the plate, is qualitative. We also appreciate that it is a functional measure of many factors that contribute to how fast a population of worms can grow, reproduce, and consume that lawn of food. However, unless they do a lifespan assay and/or measure developmental timing and specifically determine that the double mutant animals themselves are developing and/or growing more slowly, we do not think it is appropriate to use the words "slow growing" to describe the population. As they point out, the rate of consumption of food on the plate in their health assay is determined by a multitude and indeed a confluence of factors; the growth rate is one specific one that is commonly measured and has an established meaning.

    1. Reviewer #3 (Public Review):

      Sasani et al. develop and implement a new method for mutator allele discovery in the BXD mouse population. This new "IHD" method carries several notable strengths, including the ability to aggregate de novo mutations across individuals to reduce data sparsity and to combine mutation rate frequencies across multiple nucleotide contexts into a single estimate. These advantages may render the IHD method better suited to mutator discovery under certain scenarios, as compared to conventional QTL or association mapping. Overall, the theoretical premise of the IHD method is judged to be both strong and innovative, and careful simulation studies benchmark its power.

      The authors then apply their method to the BXD mouse recombinant inbred mapping population. As proof-of-principle, they first successfully re-identify a known mutator locus in this population on chr4. Next, to assess possible genetic interactions involving this known mutator, Sasani et al. condition on the chr4 mutator genotype and reimplement the IHD scan. This strategy led them to identify a second locus on chr6 that interacts epistatically with the chr4 locus; mice with "D" alleles at both loci exhibit a significantly increased burden of C>A de novo mutations, even though mice with the D allele at the chr6 locus alone show no appreciable increase in the C>A mutation fraction. This exciting discovery not only adds to the catalog of known mutator alleles, but also reveals key aspects of mutator biology. Notably, this finding reinforces the hypothesis that segregating variants in genes associated with DNA repair influence germline mutation spectra. Further, Sasani et al.'s findings suggest that some mutators may lie dormant until recombined onto a permissive genetic background. This discovery could have intriguing implications for the evolution of mutators in natural populations.

      Despite a high level of overall enthusiasm for this work, some weaknesses are identified in the IHD method, approach for nominating candidate genes within the newly identified chr6 locus, and the authors' conclusions.

      Under simulated scenarios, the authors' new IHD method is not appreciably more powerful than conventional QTL mapping methods. While this does not diminish the rigor or novelty of the authors findings, it does temper enthusiasm for the IHD method's potential to uncover new mutators in other populations or datasets. Further, adaptation of this methodology to other datasets, including human trios or multigenerational families, will require some modification, which could present a barrier to broader community uptake. Notably, BXD mice are (mostly) inbred, justifying the authors consideration of just two genotype states at each locus, but this decision prevents out-of-the-box application to outbred populations and human genomic datasets. Lastly, some details of the IHD method are not clearly spelled out in the paper. In particular, it is unclear whether differences in BXD strain relatedness due to the breeding epoch structure are fully accounted for in permutations. The method's name - inter-haplotype distance - is also somewhat misleading, as it seems to imply that de novo mutations are aggregated at the scale of sub-chromosomal haplotype blocks, rather than across the whole genome.

      Nominating candidates within the chr6 mutator locus requires an approach for defining a credible interval and excluding/including specific genes within that interval as candidates. Sasani et al. delimit their focal window to 5Mb on either side of the SNP with the most extreme P-value in their IHD scan. This strategy suffers from several weaknesses. First, no justification for using 10 Mb window, as opposed to, e.g., a 5 Mb window or a window size delimited by a specific threshold of P-value drop, is given, rendering the approach rather ad hoc. Second, within their focal 10Mb window, the authors prioritize genes with annotated functions in DNA repair that harbor protein coding variants between the B6 and D2 founder strains. While the logic for focusing on known DNA repair genes is sensible, this locus also houses an appreciable number of genes that are not functionally annotated, but could, conceivably, perform relevant biological roles. These genes should not be excluded outright, especially if they are expressed in the germline. Further, the vast majority of functional SNPs are non-coding, (including the likely causal variant at the chr4 mutator previously identified in the BXD population). Thus, the author's decision to focus most heavily on coding variants is not well-justified. Sasani et al. dedicate considerable speculation in the manuscript to the likely identity of the causal variant, ultimately favoring the conclusion that the causal variant is a predicted deleterious missense variant in Mbd4. However, using a 5Mb window centered on the peak IHD scan SNP, rather than a 10Mb window, Mbd4 would be excluded. Further, SNP functional prediction accuracy is modest [e.g., PMID 28511696], and exclusion of the missense variant in Ogg1 due its benign prediction is potentially premature, especially given the wealth of functional data implicating Ogg1 in C>A mutations in house mice. Finally, the DNA repair gene closest to the peak IHD SNP is Rad18, which the authors largely exclude as a candidate.

      Additionally, some claims in the paper are not well-supported by the author's data. For example, in the Discussion, the authors assert that "multiple mutator alleles have spontaneously arisen during the evolutionary history of inbred laboratory mice" and that "... mutational pressure can cause mutation rates to rise in just a few generations of relaxed selection in captivity". However, these statements are undercut by data in this paper and the authors' prior publication demonstrating that a number of candidate variants are segregating in natural mouse populations. These variants almost certainly did not emerge de novo in laboratory colonies, but were inherited from their wild mouse ancestors. Further, the wild mouse population genomic dataset used by the authors falls far short of comprehensively sampling wild mouse diversity; variants in laboratory populations could derive from unsampled wild populations.

      Finally, the implications of a discovering a mutator whose expression is potentially conditional on the genotype at a second locus are not raised in the Discussion. While not a weakness per se, this omission is perceived to be a missed opportunity to emphasize what, to this reviewer, is one of the most exciting impacts of this work. The potential background dependence of mutator expression could partially shelter it from the action of selection, allowing the allele persist in populations. This finding bears on theoretical models of mutation rate evolution and may have important implications for efforts to map additional mutator loci. It seems unfortunate to not elevate these points.

    1. Reviewer #3 (Public Review):

      The manuscript by Qin and Zhou presents an approach to predict dynamical properties of an intrinsically disordered protein (IDP) from sequence alone. In particular, the authors train a simple (but useful) machine learning model to predict (rescaled) NMR R2 values from sequence. Although these R2 rates only probe some aspects of IDR dynamics and the method does not provide insight into the molecular aspects of processes that lead to perturbed dynamics, the method can be useful to guide experiments.

      A strength of the work is that the authors train their model on an observable that directly relates to protein dynamics. They also analyse a relatively broad set of proteins which means that one can see actual variation in accuracy across the proteins.

      A weakness of the work is that it is not always clear what the measured R2 rates mean. In some cases, these may include both fast and slow motions (intrinsic R2 rates and exchange contributions). This in turn means that it is actually not clear what the authors are predicting. The work would also be strengthened by making the code available (in addition to the webservice), and by making it easier to compare the accuracy on the training and testing data.

    1. Reviewer #3 (Public Review):

      Alternative polyadenylation is an important aspect of RNA processing that can alter the type or amount of proteins that are produced from a gene, with consequences for many aspects of biology. Herron et al. set out to identify how the mTORC1 pathway, which regulates cellular metabolism, influences alternative polyadenylation in the mouse brain. They identified a novel mTORC1-regulated gene with alternative polyadenylation - TRIM9 - and convincingly demonstrate that its alternative polyadenylation is controlled by the CFIm complex of the cleavage and polyadenylation machinery. A major strength of these results is that the authors use multiple orthogonal methods - including PAPERCLIP, qPCR and western blotting, to demonstrate that TRIM9 is regulated by mTORC1 and CFIm. They also demonstrate that this regulation is conserved between mice and humans by using multiple different model systems, and use synthetic reporter constructs to identify the cis-regulatory elements that are responsible for TRIM9 regulation by CFIm. These results highlight the importance of alternative polyadenylation in controlling gene expression and are important for researchers wishing to understand how the mTORC1 pathway functions.

      The authors also identify that a "twin" UGUA motif in the poly(A) site of the short form of TRIM9 is responsible for its regulation by CFIm. They show that this motif is conserved across mammals and suggest that the adjacent UGUA motifs are necessary for regulation by CFIm. The evidence supporting this aspect of the manuscript is incomplete because the authors only ever mutate both UGUA motifs of TRIM9, and so it is not possible to determine whether the full motif or only one of the UGUA motifs is necessary for regulation, nor whether the effect of the two UGUA motifs is simply additive. The only evidence for the necessity of the full twin motif comes from a synthetic JUNB reporter construct, where a single UGUA motif was insufficient to induce proximal polyadenylation. However, given that there is previous evidence that individual UGUA motifs can act as enhancers of polyadenylation, this may be due to context-specific issues with the JUNB reporter, and evidence from different contexts would make the authors conclusions more convincing.

    1. Reviewer #3 (Public Review):

      The authors describe a mathematical and computational modeling study of RAF paradoxical activation (PA), a phenomenon in which RAF inhibitors exhibit a bell-shaped dose-response curve of Erk phosphorylation - activating signaling through wild-type RAF at low drug concentrations before inhibiting it at higher concentrations. They explore three distinct mechanisms that may contribute to PA - conformational autoinhibition, negative cooperativity, and drug-induced dimerization - and conclude that all three are required to best fit published data that show the PA phenomenon. They explore the effect of 14-3-3 binding to RAF both computationally and experimentally and reach the conclusion that 14-3-3 can potentiate the PA phenomenon via stabilization of the autoinhibited conformation.

      Strengths:

      One key finding will be quite valuable to the field - that paradoxical activation can arise in the absence of negative cooperativity and without any effect of the inhibitor on the propensity of RAF to dimerize, provided that there exists a "conformationally autoinhibited" state that cannot dimerize and cannot bind inhibitor. This finding is important because negative cooperativity and dimer-induction have been a major focus - arguably the main focus - of prior studies of the phenomenon and also a source of considerable confusion. Inhibitors with very different chemical structures and binding properties - type 1.5 inhibitors that are dimer-breakers (and may or may not exhibit negative cooperativity) and type I and II inhibitors that can promote dimers (and almost certainly do not exhibit negative cooperativity) can nevertheless both exhibit PA. Thus the authors' modeling provides a unifying explanation - it is not dimer-induction or negative cooperativity that is at the root of PA, rather it is that there exists an autoinhibited state that can neither bind inhibitor nor dimerize. The authors further show that negative cooperativity and dimer-induction can act in concert with "conformational autoinhibition" to modify the PA response in a drug-specific manner.

      Weaknesses:

      Unfortunately, the authors don't really explain in a straightforward manner what is going on with the conformational autoinhibition model (Figure 2A). One has to read carefully and all the way to section 3 of appendix 1 to piece it together. In short, what the math shows is that at least for certain ranges of parameter values, the presence of an inhibitor can increase the concentration of dimers, even when it does not change the equilibrium constant for dimer formation, and some of those dimers will have an active, drug-free protomer. This is because the inhibitor effectively traps open monomers, which can then capture drug-free open monomers to form active dimers (active in one subunit, inactive and drug-bound in the other). As inhibitor concentration increases, the pool of autoinhibited RAF is diminished, and eventually, it is shifted completely to fully inhibited dimers. But at low concentrations of inhibitor, there is a net increase in dimerized (active) but drug-free protomers (see figure on page 27 of the appendix). Voila, paradoxical activation, with no need to invoke negative cooperativity.

      Considering the potential for confusion around what is meant by "drug-induced dimerization" as an effect distinct from the effect of the drug in promoting RAF dimerization in their conformational autoinhibition model, it would have been helpful for the authors to explicitly address the distinction (drug-induced dimerization alters the equilibrium constant for dimerization; this is not a feature of the conformational autoinhibition model).

      Also, I am confused by Figure 3C. The figure shows, and the authors state in the text, that for type II inhibitors an f > ~1 indicates a propensity to break dimers. But type 1.5 inhibitors should break dimers, and Type I and II inhibitors should promote dimers (at least some Type I and II drugs have been shown to promote kinase dimers). Seems that the predictions of the model are inconsistent with experimental data, at least for some inhibitors.

      A large part of the paper deals with the effect of 14-3-3 binding. In my view, this part of the manuscript is not particularly helpful. There is no evidence (that I am aware of) that 14-3-3 concentrations vary significantly, or that their variation affects RAF activity/signaling. Considering their abundance relative to RAF, and relatively high affinity for RAF, it is likely that both autoinhibited and active RAF are saturated with 14-3-3. (RAF that is not 14-3-3-bound is likely mostly bound to chaperones and not active). That said, the authors' conclusion (based on modeling) that 14-3-3 can increase the extent of paradoxical activation by stabilizing the autoinhibited state seems sensible, but hard to reconcile with their experimental result where they find increased basal signaling with 14-3-3 over-expression. It is also difficult to understand how increased 14-3-3 binding to RAF could lead to active RAF dimers that are not inhibited at 10-100 uM concentrations of potent RAF dimer inhibitors like LY3009120 (Fig. 5C). It seems more likely that 14-3-3 overexpression is promoting Erk phosphorylation in a manner that is (at least partially) Raf-independent. To their credit, the authors acknowledge this concern.

      Finally, one comment regarding the presentation. The authors discuss conformational inhibition and 14-3-3 binding as if they are promoting and/or inducing paradoxical activation. This is pervasive in the paper, including in the title, and is distracting and potentially will mislead some readers. Obviously, it is RAF inhibitor that induces or promotes paradoxical activation. Conformational autoinhibition - mediated by 14-3-3 - is a feature of the system that makes paradoxical activation possible.

    1. Reviewer #3 (Public Review):

      The authors employed a set of cell-based and animal studies with tumor model systems that harbor a genetically deleted specific isoform of p73 to identify a novel function of this isoform in the regulation of lipid metabolism and obese disorder, which are associated with tumorigenesis. Interestingly, this new function was found to be through the increase in leptin expression. This is probably the first study showing the connection of the p73 family members with leptin, a molecule that has been shown to play a critical role in obesity and metabolism. Overall, their findings are novel, interesting, and important.

    1. Reviewer #3 (Public Review):

      Controlling the shape of biological tubes (blood vessels, lungs, etc) is essential for optimizing the traffick of liquid and gas in organisms. Tracheal tubulogenesis of Drosophila embryos is regulated separately in two dimensions, width, and length. Molecules controlling the tracheal tube length function at three levels of location, luminal ECM, plasma membrane mediating cell-apical ECM interaction, and the signaling at the membrane/cell junction. In this paper, Pinheiro et al. reported a novel function of a scavenger receptor family molecule, Emp, which mediates endocytosis of a subset of luminal proteins including chitin deacetylates Serp and Verm that are required for restricting the tube length. It was previously shown that endocytosis and recycling of Serp and Verm maintain the level of luminal chitin deacetylates for keeping the property of the apical ECM to restrict the tube length (10.1016/j.celrep.2014.03.066).

      This work is novel in two ways. First, Emp was shown to mediate the endocytosis of Serp and Verm by most likely interacting with the LDLr domains of cargo molecules and acting in parallel with the clathrin-mediated endocytosis to clear luminal materials. Second and surprisingly, the Emp-mediate endocytosis is coupled with the widespread alteration of the apical plasma membrane, including reduction of junctional E-cadherin and Crumbs, apical membrane protein DAAM1, and the cortical membrane skeleton component beta heavy spectrin (Kst). The elevation of junctional Crumbs protein in Emp mutants is noteworthy because the authors showed Crumbs was selectively upregulated in the longitudinal cell junctions. This change in Crumbs polarity may be related to the axial over-elongation of the trachea in Emp mutants. Furthermore, the authors showed that Src42A, which was previously shown to promote tube elongation, is also regulated negatively by Emp.

      Overall, the information provided in this work supports a model of endocytic coupling of luminal materials and the axial polarity of the tracheal tube. This leads to a new idea distinct (but none-exclusive) from the previously proposed mechanical coupling model (10.1016/j.celrep.2014.03.066) and would advance a fundamental understanding of biological tube shape regulation. One critical point of linking endocytosis to the axial polarity is the selective enrichment of Crumbs to the longitudinal cell boundaries (10.1371/journal.pgen.1007824), which is shown to be enhanced in Emp mutants (Fig. 5D-F). Discussing how the junction-enriched Crmbs contribute to selective axial cell elongation will be desirable to expand the scope of this work. This point is essential, given that the expression of the dominant-active form of Crumbs lacking the extracellular domain (Crumbs-intra) is mislocalized in the cytoplasmic puncta promotes axial cell elongation (Laprise et al., 2010).

    1. Reviewer #3 (Public Review):

      Because of the position of pigeon embryos in eggs, light exposure will only stimulate the right eye, leading to lateralisation of brain responses and behaviour. Lorenzi and colleagues injected manganese chloride into pigeon eggs, to assess neuronal activation in the embryonic brain. While the eggs were placed in the light or dark, manganese ions accumulated in neurons that were activated (in cell bodies and axons), which was then visualized with MRI of the embryos before hatching. The authors report lateralisation of neuronal activity in three brain regions, which could potentially be important for our understanding of experience-dependent development of lateralised neural activation.

      The tectofugal pathway in pigeons projects from the retina to the optical tectum, then to the nucleus rotundus in the thalamus, and then to the entopallium. The thalamofugal pathway projects from the retina to the GLd in the thalamus, and then to the wulst in the hyperpallium. The two pathways involve different thalamic nuclei (e.g., Deng 2006). In the methods and throughout the manuscript it should be specified which thalamic region is used as ROI.

      This manuscript only describes neural activity, but the MEMRI technique should also be used to assess the effect of experimental manipulations on axonal connectivity. It is important to learn about the asymmetry of contralateral projections in the light vs dark groups for answering the research question.

      There is an overinterpretation of post-hoc statistics that are reported without correction for multiple testing. The wulst light group lateralization is probably not actually different from zero (uncorrected p=0.04).

      The first line in the discussion states that there is thalamofugal lateralization, but no lateralization in the tectofugal pathway. To my understanding, previous literature reported it the other way around: in altricial pigeons, light exposure in the egg mainly affected the tectofugal pathway (Deng & Rogers 2002), while the thalamofugal pathway in pigeons was not lateralized (Strockens et al., 2013). The manuscript should compare the current findings with the literature and discuss differences.

      Moreover, the tectum is the only region shown here from the tectofugal pathway. However, lateralization of contralateral connections is expected from tectum to the nucleus rotundus in the thalamus, and thus lateralization of activation may only arise in downstream brain regions from the optical tectum. Therefore, the conclusion that there is no lateralization in the tectofugal pathway is not supported by the data.

      In conclusion, I think it is interesting and worthwhile that the authors assessed neural activity in response to visual stimulation in the embryo prior to hatching, but multiple methodological weaknesses and unclarities should be addressed.

    1. Reviewer #3 (Public Review):

      In this latest installment of a growing body of work from Henry Colecraft's lab in which native enzymes, ion channels, and other machinery are hijacked for therapeutic potential, cells can be made to respond to beta-adrenergic signals even when lacking the critical adaptor protein AKAP9. Normally, the cardiac repolarizing current IKs is enhanced in the face of beta-adrenergic signaling when increased cAMP activates PKA anchored to the channel protein by AKAP9. PKA phosphorylates the channel, increasing function or density in the membrane, especially during exercise or fright. Under these circumstances, when AKAP9 is missing in patients, the action potential fails to repolarize in a timely manner and arrhythmias can result. In this study, targeting the PKA catalytic or regulatory subunit to the E1 auxiliary channel subunit via a targeting nanobody restores at least some of the normal modulation in the presence of cAMP. This primary finding demonstrates a potential therapeutic approach when mutations disrupt its interaction with the channel complex.

      A secondary finding of the study is that, contrary to expectation, targeting the enzyme to the Q1 alpha subunit C-terminus does not restore modulation but rather inhibits current by tying up the protein in the ER. Retention apparently depends on phosphorylation because a kinase-dead PKA catalytic subunit exhibits normal current. These findings demonstrate that the efficacy of correction is critically dependent on the site of recruitment. The results represent a starting point whereby kinase-based signaling can be synthetically harnessed to restore normal function in a disease setting.

      The strengths of the study are the therapeutic potential of its principal finding and the clever approach to redirecting cellular components. Controls for the constructs are carefully designed and executed. Most of the conclusions are supported by the data presented. The weaknesses are minor and include providing more than an exemplar to support findings of enhanced phosphorylation and an accounting of how the findings from immunofluorescent images were quantitatively established. The study represents a major contribution to an emerging field of study in which modulation is induced by the proximity of enzymes to otherwise undruggable targets.

    1. Reviewer #3 (Public Review):

      This manuscript proposes to tackle a very interesting and methodologically challenging topic: the mechanistic underpinnings of neural specialization in the infant brain. The authors presented 4- to 7-month-old infants with social and non-social stimuli while their neural, hemodynamic, and metabolic activity was monitored, and they report a complex pattern of relationships between neural and metabolic or hemodynamic responses during social processing on the one hand, and during non-social processing on the other hand.

      The approach described in this manuscript is very interesting and the combined use of EEG and bNIRS data appears very promising. However, there is some confusion between the initial aims of the study, and the analyses performed, which jeopardizes the clarity and the impact of this manuscript. Besides, the predictions of the authors are often underspecified which complexifies the interpretation of the results.

      Based on its abstract, the goal of this work is to "combine simultaneous measures of coordinated neural activity metabolic rate and oxygenated blood supply to measure emerging specialization in the infant brain". The introduction nicely elaborates on the "interactive specialization theory" and the potential role of the interplay between brain energy consumption and neural activity in the emergence of functionally specialized brain regions during development. The authors present a novel multimodal approach, with potentially important implications for the study of brain specialization as a function of experience or maturation. Yet the experimental procedure presented in this manuscript only assesses specialized brain activity in response to social processing in 4- to 7-month-old infants, using multimodal neuroimaging.<br /> Indeed, the authors presented 4- to 7-month-old infants with social and non-social stimuli while their neural, hemodynamic, and metabolic activity was monitored. The authors report significant differences between the two conditions in terms of neural activity in the delta, alpha, beta, and gamma bands; as well as in the pattern of hemodynamic to metabolic coupling. Using a GLM approach, the authors report on fNIRS channels and EEG sensors showing significant relationships between the evoked neural activity in the beta and gamma frequency bands, and each of the bNIRS signals (HbO, HbR & CCO), in the social and in the non-social conditions. The authors identify a particular fNIRS channel overlaying posterior STS, showing a positive relationship between Pz EEG beta activity and HbO, as well as CCO, together with a negative relationship between that same neural activity and HbR, in the social condition. This pattern of activity was not observed in the non-social condition.<br /> Overall, these results indicate differential neural responses to social and non-social stimuli, coupled metabolic and hemodynamic activity in response to social as well as nonsocial stimuli. These results additionally indicate coordinated metabolic, hemodynamic, and neural responses in brain regions selective for social processing, but it does not allow us to conclude that this coordinated activity is actually related to the functional specialization process (e.g. last sentence of the abstract).

      Another weakness of this manuscript relates to the unclear or underspecified motivations behind some of the performed analyses. For example, the authors contrast brain responses to social vs. baseline, non-social vs. baseline, and social vs. non-social. For clarity in the manuscript, the authors should specify the motivation behind each of these contrasts and their predictions.

      Another example is in the analysis of the hemodynamic and metabolic coupling analysis, here the authors analyze only the social vs. baseline and non-social vs. baseline contrast, and they do not analyze the social vs non-social contrast. It would be useful for the reader to understand why only these two contrasts are performed and not the social vs. non-social, and what are the predictions of the authors.

      Finally, the core result of this work derives from the final GLM analysis which relates EEG activity to hemodynamic or metabolic responses. This analysis implies the inspection of interactions between 3 neuroimaging modalities, with 4 EEG measures, 2 hemodynamic measures, and 1 metabolic measure, which represents a very rich and relatively complex analytic approach. Unfortunately, the predictions are not clearly specified, which makes results interpretation difficult.

      Based on the results (L160-162) and discussion (L233-235) sections, it appears that the authors aim at identifying brain regions showing a precise pattern of activity, with a positive relationship between EEG activity and HbO/CCO responses together with a concurrent negative relationship between EEG and HbR responses in response to social events, but not in response to non-social events. Importantly, the social vs. non-social contrast seems crucial to assess the selectivity of the response. Yet, the authors analyze the 3 chromophores separately, and they do not contrast the two conditions (figure 3). As a result, the authors are limited to reporting a descriptive pattern of relationships between EEG and HbO/HbR/CCO activations for the social condition. And another one for the non-social condition. Overall, the authors conclude that channel 14, overlaying the right TPJ, shows the expected pattern of activity, specifically in response to social stimuli. Yet, this statement is only supported by visual inspection/comparison of the results between the social vs baseline and non-social vs baseline conditions. The authors do not assess analytically the differential patterns of activations between the two conditions. Instead, a GLM including all 3 chromophores and contrasting the two experimental conditions would allow us to directly test the predicted pattern of activity, and the selectivity of the activity for social stimuli.

    1. Reviewer #3 (Public Review):

      The authors used passive acoustic monitoring over a vast range of the North Atlantic to study the call rates of fin whales. They found a 'take over' of a new rythm (inter call intervals) during their study period. This was interpreted as a change in song production.

      I am not completely convinced the authors are correct in describing this change in rate as a change in the song. Even though fin whale calls are evidently a male mating ground display, little is known about its function. Compared to humpback whales with their impressive repertoire of vocalizations, repeating themselves on the breeding grounds after some tens of minutes and therefore qualifying as a very slow 'song' similar to bird song, fin whale only emit a single type of call, which is remaining the same throughout the study period. It can be contested, I would assume, that a ,erely change the repetition rate of calls, even though seemingly done here in an 'overtake' fasion, can qualify as a change and learning of song,

    1. Reviewer #3 (Public Review):

      The authors have made significant improvements in addressing my major concerns raised during the previous review. However, I still have some lingering concerns regarding the quantification and statistical analysis presented in the manuscript. Specifically, there is a lack of robust quantification and statistical analysis to support the conclusions drawn, particularly in relation to the numbers of DG, CA1, and CA3 neurons.

      To strengthen the validity and reliability of the findings, I would strongly recommend the authors to incorporate a more rigorous quantitative approach in their research. This could involve implementing stereological methods or other appropriate techniques to accurately estimate the numbers of neurons in the DG, CA1, and CA3 regions. By doing so, the authors would enhance the credibility of their conclusions and provide more solid evidence for their claims.

    1. Reviewer #3 (Public Review):

      As naturalistic neuroscience becomes increasingly popular, the importance of new computational tools that facilitate the study of animals behaving in minimally constrained environments grows. Yi et al convincingly demonstrate the usefulness of their new method on data from neuroethological studies involving multiple animals, including those with social interactions. Briefly, their method improves upon prior semi-supervised machine learning methods in that extracted latent variables can be more cleanly separated into those representing the behavior of individual subjects and those representing social interactions between subjects. Such an improvement is broadly useful for downstream analysis tasks in multi-subject or social neuroethological studies.

      Strengths:<br /> The authors tackle an important problem encountered in behavior analyses in an emerging subfield of neuroscience, naturalistic social neuroscience. They make a case for doing so using semi-unsupervised methods, a toolbox which balances competing scientific needs for building models using large neural-behavioral datasets and for model explainability. The paper is well written, with well-designed figures and relevant analyses that make for an enjoyable reading experience.

      The authors provide a remarkable variety of examples that make a convincing case for the utility of their method when used by itself or in conjunction with other data analysis techniques commonly used in modern neuroscience (behavioral motif extraction, neural decoding, etc.). The examples show not just that the extracted latents are more disentangled, but also that the improvement in disentangling has positive effects in downstream analysis tasks.

      Weaknesses:<br /> While the paper does a great job of applying the method to real world data, the components of the method itself are not as thoroughly investigated. For example, the contribution of the novel Cauchy-Schwarz regularization technique has not been systematically investigated. This could be done either by sharing additional data where hyperparameters control the contribution of the regularizer, or cite relevant papers where such an analysis have been carried out. It would also be valuable to understand what other regularization techniques might potentially have been applicable here.

      The authors conclude from their empirical investigations that the specific prior distribution does not matter to the regularization process. This seems reasonable given that the neural network can learn a complex and arbitrary transformation of the data during training. It would be helpful if the authors could cite prior work where this type of prior distribution does matter and how their approach is different from such prior work. If there is a visualization/explainability related motivation for choosing one prior distribution over another, this could be clarified.

    1. Reviewer #3 (Public Review):

      This paper reveals interesting physical connections between Elg1 and CST proteins that suggest a model where Elg1-mediated PCNA unloading is linked to regulation of telomere length extension via Stn1, Cdc13, and presumably Ten1 proteins. Some of these interactions appear to be modulated by sumolyation and connected with Elg1's PCNA unloading activity. The strength of the paper is in the observations of new interactions between CST, Elg1, and PCNA. These interactions should be of interest to a broad audience interested in telomeres and DNA replication.

      What is not well demonstrated from the paper is the functional significance of the interactions described. The model presented by the authors is one interpretation of the data shown, and proposes that the role of sumolyation is temporally regulate the Elg1, PCNA and CST interactions at telomeres. This model makes some assumptions that are not demonstrated by this work (such as Stn1 sumolyation, as noted) and are left for future testing. Alternative models that envision sumolyation as a key in promoting spatial localization could also be proposed based on the data here (as mentioned in the discussion), in addition to or instead of a role for sumolyation in enforcing a series of switches governing a tightly sequenced series of interactions and events at telomeres. Critically, the telomere length data from the paper indicates that the proposed model depicts interactions that are not necessary for telomerase activation or inhibition, as telomeres in pol30-RR strains are normal length and telomeres in elg1∆ strains are not nearly as elongated as in stn1 strains. One possibility mentioned in the paper is the PCNAS and Elg1 interactions are contributing to the negative regulation of telomerase under certain conditions that are not defined in this work. Could it also be possible that the role of these interactions is not primarily directed toward modulating telomerase activity? It will be of interest to learn more about how these interactions and regulation by Sumo function intersect with regulation of telomere extension.

    1. Reviewer #3 (Public Review):

      The introduction/background is excellent. It reviews evidence showing that the extinction of conditioned responding is regulated by noradrenaline and suggests that the locus coeruleus (LC) may be a critical locus of this regulation. This naturally leads to the aim of the study: to determine whether the locus coeruleus is involved in the extinction of an appetitive conditioned response. Overall, the study is well-designed, nicely conducted and the results advance our understanding of the role of the LC in the extinction of conditioned behaviour. As such, I believe that these results will be of interest to readers. I do, however, feel that the paper would benefit from the inclusion of additional data to clarify the impact of the LC manipulations (stimulation and inhibition) on performance in the task; and some comment regarding the likely source of differences between the groups at test.

    1. Reviewer #3 (Public Review):

      Complex behavior requires complex neural control involving multiple brain regions. The currently available tools to measure neural activity in multiple brain regions in small animals are limited and often involve obligatory head-fixation. The latter, obviously, impacts the behaviors under study. Hur and colleagues present a novel recording device, the E-Scope, that combines optical imaging of fluorescent calcium imaging in one brain region with high-density electrodes in another. Importantly, the E-Scope can be implanted and is, therefore, compatible with usage in freely moving mice. The authors used their new E-Scope to study neural activity during social interactions in mice. They demonstrate the presence of neural correlates of social interaction that happen simultaneously in the cerebellum and the anterior cingulate cortex.

      The major accomplishment of this study is the development and introduction of the E-Scope. The evaluation of this part can be short: it works, so the authors succeeded.

      The authors managed to reduce the weight of the implant to 4.5 g, which is - given all functionality - quite an accomplishment in my view. However, a mouse weighs between 20 and 40 g, so that an implant of 4.5 g is still quite considerable. It can be expected that this has an impact on the behavior and, possibly, the well-being of the animals. Whether this is the case or not, is not really addressed in this study. The authors suffice with the statement that "Recorded animals made more contact with the other mouse than with the object (Figure 2A), suggesting a normal preference for social contact with the E-Scope attached."

      Overall, the description of animal behavior is rather sparse. The methods state only that stranger age-matched mice were used, but do not state their gender. The nature of the social interactions was not described? Was their aggressive behavior, sexual approach and/or intercourse? Did the stranger mice attack/damage the E-Scope? Were the interactions comparable (using which parameters?) with and without E-Scope attached? It is not even described what the authors define as an "interaction bout" (Figure 2A). The number of interaction bouts is counted per 7 minutes, I presume? This is not specified explicitly.

      In Figure 1 D-G, the authors present raw data from the neurophysiological recordings. In panel D, we see events with vastly different amplitudes. It would be very insightful if the authors would describe which events they considered to be action potentials, and which not. Similarly, the raw traces of Figure 1E are declared to be single-unit recordings of Purkinje cells. Partially due to the small size of the traces (invisible in print and pixelated in the digital version), I have a hard time recognizing complex spikes and simple spikes in these traces. This is a bit worrisome, as the authors declare the typical duration of the pause in simple spike firing after a complex spike to be 20-100 ms. In my experience, such long pauses are rare in this region, and definitely not typical. In the right panel of Figure 1A, an example of a complex spike-induced pause is shown. This pause is around 15 ms, so not typical according to the text, and starts only around 4 ms after the complex spike, which should not be the case and suggests either a misalignment of the figure or the detection of complex spike spikelets as simple spikes, while the abnormally long pause suggests that the authors fail to detect a lot of simple spikes. The authors could provide more confidence in their data by including more raw data, making explicit how they analyzed the signals, and by reporting basic statistics of firing properties (like rate, cv or cv2, pause duration). In this respect, Figure 2 - figure supplement 3 shows quite a large percentage of cells to have either a very low or a very high firing rate.

      The number of Purkinje cells recorded during social interactions is quite low: only 11 cells showed a modulation in their spiking activity (unclear whether in complex spikes, simple spikes or both. During object interaction, only 4 cells showed a significant modulation. Unclear is whether the latter 4 are a subset of the former 11, or whether "social cells" and "object cells" are different categories. Having so few cells, and with these having different types of modulation, the group of cells for each type of modulation is really small, going down to 2 cells/group. It is doubtful whether meaningful interpretation is possible here.

      This brings us to the next point: neural correlates of social interaction are notoriously difficult to interpret. Social behavior is complex, and involves the processing of sensory cues (olfaction, touch (whiskers), visual and auditory), the production of ultrasonic vocalizations (in specific contexts), movements, and emotional behavior (fear, pleasure, sexual interest). In other words, neural activity patterns observed during social interaction do not necessarily relate specifically to social interaction, but can also occur in a non-social context. The authors control this by comparing social interactions with object interactions, but I miss a direct comparison between the two conditions, both in terms of behavior (now only the number of interactions is counted, not their duration or intensity), and in terms of neural activity. There is some analysis done on the interaction between movement and cerebellar activity (Figure 2 - figure supplement 4), but it is unclear to what extent social interactions and movements are separated here. It would already help to indicate in the plots with trajectories (e.g., Fig. 2H) indicate the social interactions (e.g., social interaction-related movements in red, the rest of the trajectories in black).

      The neuron count in the anterior cingulate cortex is much higher than for the cerebellum, but also here it is not so clear what is "social" and what is "non-social". In Figure 3G-H, the authors indicate a near-perfect separation between cells active during social encounters and those active during object encounters. This could indicate that there is here indeed a social aspect, but as we do not know to what extent the sensory and motor aspects differ between social and non-social interactions, this is still hard to interpret.

      Finally, the authors show that there are correlations between the modulation in neurons of the anterior cingulate cortex and cerebellar neurons related to bouts of social activity. Here, it could be interesting to see whether there are differences in latency between the two brain areas.

      In conclusion, the authors present a novel method to record neural activity with single cell-resolution in two brain regions in freely moving mice. Given the challenges associated with understanding of complex behaviors, this approach can be useful for many neuroscientists. The authors demonstrate the potential of their approach by studying social interactions in mice. Clearly, there are correlations in the activity of neurons in the anterior cingulate cortex and the cerebellum related to social interactions. To bring our understanding of these patterns to a higher level, more detailed analyses (and probably also larger group sizes of cerebellar neurons) are required, though.

    1. Reviewer #3 (Public Review):

      This study investigated what kind of reference (allocentric or egocentric) frame we used for perception in darkness. This question is essential and was not addressed much before. The authors compared the perception in the walking condition with that in the stationary condition, which successfully separated the contribution of self-movement to the spatial representation. In addition, the authors also carefully manipulated the contribution of the waiting period, attentional load, vestibular input, testing task, and walking direction (forward or backward) to examine the nature of the reference frame in darkness systematically.

      I am a bit confused by Figure 2b. Allocentric coordinate refers to the representation of the distance and direction of an object relative to other objects but not relative to the observer. In Figure 2, however, the authors assumed that the perceived target was located on the interception between the intrinsic bias curve and the viewing line from the NEW eye position to the target. This suggests that the perceived object depends on the observer's new location, which seems odd with the allocentric coordinate hypothesis.

      According to Fig 2b, the perceived size should be left-shifted and lifted up in the walking condition compared to that in the stationary condition. However, in Figure 3C and Fig 4, the perceived size was the same height as that in the baseline condition.

      Is the left-shifted perceived distance possibly reflecting a kind of compensation mechanism? Participants could not see the target's location but knew they had moved forward. Therefore, their brain automatically compensates for this self-movement when judging the location of a target. This would perfectly predict the left-shifted but not upward-shifted data in Fig 3C. A similar compensation mechanism exists for size constancy in which we tend to compensate for distance in computing object size.

      According to Fig 2a, the target, perceived target, and eye should be aligned in one straight line. This means that connecting the physical targets and the corresponding perceived target results in straight lines that converge at the eye position. This seems, however, unlikely in Figure 3c.

    1. Reviewer #3 (Public Review):

      Prior studies have shown that locomotion (e.g., running) modulates mouse V1 activity to a similar extent as visual stimuli. However, it's unclear if these findings hold in species with more specialized and advanced visual systems such as nonhuman primates. In this work, Liska et al. leverage population and single neuron analyses to investigate potential differences and similarities in how running modulates V1 activity in marmosets and mice. Specifically, they discovered that although a shared gain model could describe well the trial-to-trial variations of population-level neural activity for both species, locomotion more strongly modulated V1 population activity in mice. Furthermore, they found that at the level of individual units, marmoset V1 neurons, unlike mice V1 neurons, experience suppression of their activity during running.

      A major strength of this work is the introduction and completion of primate electrophysiology recordings during locomotion. Data of this kind was previously limited, and this work moves the field forward in terms of data collection in a domain previously inaccessible in primates. Another core strength of this work is that it adds to a limited collection of cross-species data collection and analysis of neural activity at the single-unit and population level, attempting to standardize analysis and data collection to be able to make inferences across species.

      However, the authors did not take full advantage of the quantity and diversity of the marmoset visual cortex recordings in their analyses. They mention recording and analyzing the activity of peripheral V1 neurons but mainly present results involving foveal V1 neurons. Foveal neurons, with their small receptive fields strongly affected by precise eye position, would seem to be less likely to be comparable to rodent data. If the authors have a reason for not doing so, they should provide an explanation. Given that the marmosets are motivated to run with liquid rewards, the authors should provide more context as to how this may or may not affect marmoset V1 activity. Additionally, the lack of consideration of eye movements or position presents a major absence for the marmoset results, and fails to take advantage of one of the key differences between primate and rodent visual systems - the marmosets have a fovea, and make eye movements that fixate in various locations on the screen during the task. Finally, the model provides a strong basis for comparison at the level of neuronal populations, but some methodological choices are insufficiently described and may have an impact on interpreting the claims.

      Overall, the methods and data are supportive of the main claims of the work. The use of single neuron and population level approaches demonstrate that the activity of V1 in mice and marmoset is categorically different. Since primate V1 is so diverse, this limits the interpretation of the cross-species comparison. Still, the work is a great step forward in the field, especially with the novel methodology of collecting neural activity from running primates.

    1. Reviewer #3 (Public Review):

      Yin-wei Lin et al set out to visualize the inactive conformation of full-length Bruton's Tyrosine Kinase (BTK), a molecule that has evaded high-resolution structural studies in its full-length form to this date. An open question in the field is how the Pleckstrin Homology-Tec Homology (PHTH) domain inhibits BTK activity, with multiple competing models in the field. The authors used a complimentary set of biophysical techniques combined with well-thought-out stabilizing mutations to obtain structural insights into BTK regulation in its full-length form. They were able to crystallize the full-length construct of BTK but unfortunately, the PHTH was not resolved yielding a structure similar to that previously obtained in the field. The investigation of the same construct by SAXS yielded an elongated structural model, consistent with previous SAXS studies. Using cryo-EM the authors obtained a low-resolution model for the FL BTK with a loosely connected density assigned to the dynamic PHTH around the compact SH2-SH3-Kinase Domain (KD) core. To gain further molecular insights into PHTH-KD interactions the authors followed a previously reported strategy and generated a fusion of PHTH-KD with a longer linker, yielding a crystal structure with a novel PHTH-KD interface which they tested in biochemical assays. Lastly, Yin-wei Lin et al crystallized the BTK KD in a novel partially active state in a "face-to-face" dimer with kinases exchanging the activation loops, although partially disordered, being theoretically perfectly positioned for transphosphorylation. Overall this presents a valiant effort to gain molecular insights into what clearly is a dynamic regulatory motif on BTK and is a valuable addition to the field.

      However, this work can be improved by considering these points:

      1) The cryo-EM reconstructions are potentially over-interpreted. The reported resolution for all of the analyzed reconstructions is better than 8Å, at which point helices should be recognized as well-resolved structural elements. In the current view/depiction of the cryo-EM maps/models it is hard to see such structural features and it would be great if the authors could include a panel showing maps at higher thresholds to show correspondence between the helices in the kinase C lobe and the cryo-EM maps. Otherwise, the overall positioning of the models within the cryo-EM maps is hard to evaluate and may very well be wrong. (Fig 4, S2).

      2) With the above in mind, if the maps are not at the point where helices are well resolved, it may be beneficial to low-pass filter the maps to a more conservative resolution for fitting, analysis, and representation. (Fig 4, S2).

      3) It would be valuable to get a quantitative metric on the model/map fitting for the cryo-EM work. One good package for this is Situs which provides cross-correlation values for the top orthogonal fits, without user input for initial fitting. This would again increase the confidence in the correctness of model positioning on the map. (Fig 4, S2).

      4) It would be great to see 2D class averages from the particles contributing to each of the 3D classes. Theoretically, a clear bright "blob" (hypothesized to be the PHTH domain) should be observable in the 2D class averages. In the current 2D class averages that region is unconvincingly weak. (Fig 4, S2).

      5) It seems like there was quite a large circular mask applied during 2D classification. Are authors confident that the weak density attributed to the PHTH domain is not neighboring particles making their way into the extraction box? It would be great if the authors would trim their particle stack with a very stringent inter-particle distance cutoff (or report the cutoff in the manuscript if already done so) to minimize this possibility.

      6) The cryo-EM processing may benefit from more stringent particle picking. The authors picked over 2M particles from 750 micrographs which likely represents very heavy overpicking. I would encourage the authors to re-pick the micrographs with 2D class averages and use more stringent metrics to reduce the overpicking. This may result in higher-resolution reconstructions. (Fig 4, S2).

      7) The Dmax from SAXS for the Full Length BTK is at 190Å. It would be great if the authors could make a cartoon of what domain arrangement may satisfy this distance, as it is quite extended for such a small particle. Can the authors rule out dimerization at SAXS concentrations? (Fig 1).

      8) In Figure S1 (C) it seems that the curves are just scattering curves with Guinier plots in the inserts, but are labeled as Guinier plots in the legend. The Guinier plots for some samples (FL 4P1F) show signs of aggregation, which may complicate the analysis, it could be beneficial to redo.

      9) Have the authors verified that the activation loop mutations that they introduce do not disrupt the PHTH binding as they previously reported an activation loop on BTK to interact with PHTH, an interaction they do not see here? If so, a citation would be helpful in the text. If not, testing this would strengthen the paper.

      10) Can the authors comment on the surfaces which are accessible and inaccessible to the PHTH in the crystal (Fig 3E)? The fact that PHTH doesn't adopt a stable conformation in the solvent channel to some degree indicates that the accessible interaction surfaces are not suitable for PHTH interactions, as the "effective concentration" of the PHTH would be quite high. Are these surfaces consistent with the cryo-EM analysis?

      11) For the novel active state dimer of the Kinase Domain it would be great to see some functional validation of the dimerization interface. It is structurally certainly quite suggestive, but without such experiments the functional significance is unclear. If appropriate mutations have been published previously a citation would be helpful.

    1. Reviewer #3 (Public Review):

      Verdikt et al. focused on the influence of Δ9-THC, the most abundant phytocannabinoid, on early embryonic processes. The authors chose an in vitro differentiation system as a model and compared the proliferation rate, metabolic status, and transcriptional level in ESCs, exposure to Δ9-THC. They also evaluated the change of metabolism and transcriptome in PGCLCs derived from Δ9-THC-exposed cells. All the methods in this paper do not involve the differentiation of ESCs to lineage-specific cells. So the results cannot demonstrate the impact of Δ9-THC on preimplantation developmental stages. In brief, the authors want to explore the impact of Δ9-THC on preimplantation developmental stages, but they only detected the change in ESCs and PGCLCs derived from ESCs, exposure to Δ9-THC, which showed the molecular characterization of the impact of Δ9-THC exposure on ESCs and PGCLCs.

    1. Reviewer #3 (Public Review):

      This paper presents the cognitive implications of claims made in two accompanying papers (Berger et al. 2023a, 2023b) about the creation of rock engravings, the intentional disposal of the dead, and fire use by Homo naledi. The importance of the paper, therefore, relies on the validity of the claims for the presence of socio-culturally complex and cognitively demanding behaviors that are presented in the associated papers. Given the archaeological, hominin, and taphonomic analyses in the associated papers are not adequate to enable the exceptional claims for naledi-associated complex behaviors, the inferences made in this paper are currently inadequate and incomplete.

      The claimed behaviors are widely recognized as complex and even quintessential to Homo sapiens. The implications of their unequivocal association with such a small-brained Middle Pleistocene hominin are thus far reaching. Accordingly, the main thrust of the paper is to highlight that greater cognition and complex socio-cultural behaviors were not necessarily associated with a positively encephalized brain. This argument begs the obvious question of whether absolute brain size and/or encephalization quotient (i.e., the actual brain volume of a given species relative the expected brain size for a species of the same average body size) can measure cognitive capacity and the complexity of socio-cultural behaviors among late Middle Pleistocene hominins.

      Claims for a positive correlation between absolute and/or relative brain size and cognitive ability are not common in discussions surrounding the evolution of Middle- and Late Pleistocene hominin behavior. Currently, the bulk of the evidence for early complex technological and social behaviors derives from multiple sites across South Africa and postdates the emergence of H. sapiens by more than 100,000 years. Such lag in the expression of complex technologies and behaviors within our species renders the brain size-implies-cognitive capacity argument moot. Instead, a rich body of research over the past several decades has focused on aspects related to socio-cultural, environmental, and even the wiring of the brain in order to understand factors underlying the expression of the capacity for greater behavioral variability. In this regard, even if the claimed evidence for complex behaviors among the small-brained naledi populations proves valid, the exploration of the specific/potential socio-cultural, neuro-structural, ecological and other factors will be more informative than the emphasis on absolute/relative brain size.

      The paper presents as supporting evidence previous claims for the appearance of similar complex behaviors predating the emergence of our species, H. sapiens, although it does acknowledge their controversial nature. It then uses the current claims for the association of such behaviors with H. naledi as decisive. Given the inadequate analyses in the accompanying papers and the lack of evidence for stone tools in the naledi sites, the present claims for the expression of culturally and symbolically mediated behaviors by this small-brained hominin must be adequately established. The importance of the paper thus rests on the validity of the claimed evidence--including contextual aspects--for rock engraving, mortuary practices, and the use of fire presented in the associated two papers. The claims in both associated papers are inadequate, incomplete, and largely assumption- (rather than evidence) based. As responsible and ethical researchers, the team must return to the sites, conduct the required standard chronomoetric and taphonomic studies and weigh the strength of the evidence before proceeding with the current claims.

    1. Reviewer #3 (Public Review):

      Lee Berger and colleagues argue here that markings they have found in a dark isolated space in the Rising Star Cave system are likely over a quarter of a million years old and were made intentionally by Homo naledi, whose remains nearby they have previously reported. As in a European and much later case they reference ('Neanderthal engraved 'art' from the Pyrenees'), the entangled issues of demonstrable intentionality, persuasive age and likely authorship will generate much debate among the academic community of rock art specialists. The title of the paper and the reference to 'intentional designs', however, leave no room for doubt as to where the authors stand, despite avoidance of the word art, entering a very disputed terrain. Iain Davidson's (2020) 'Marks, pictures and art: their contributions to revolutions in communication', also referenced here, forms a useful and clearly articulated evolutionary framework for this debate. The key questions are: 'are the markings artefactual or natural?', 'how old are they?' and 'who made them?, questions often intertwined and here, as in the Pyrenees, completely inseparable. I do not think that these questions are definitively answered in this paper and I guess from the language used by the authors (may, might, seem etc) that they do not think so either.

      First, a few referencing issues: the key reference quoted for distinguishing natural from artefactual markings (Fernandez-Jalvo et al. 2014), whilst mentioned in the text, is not included in the references. In the acknowledgements, the claim that "permits to conduct research in the Rising Star Cave system are provided by the South African National Research Foundation" should perhaps refer rather to SAHRA? In the primary description of their own markings from Rising Star and their presumed significance, there are, oddly, several unacknowledged quotes from the abstract of one of the most significant European references (Rodriguez-Vidal et al. 2014). These need attention.

      Before considering the specific arguments of the authors to justify the claims of the title, we should recognise the shift in the academic climate of those concerned with 'ancient markings' that has taken place over the past two or three decades. Before those changes, most specialists would probably have expected all early intentional markings to have been made by Homo sapiens after the African diaspora as part of the explosion of innovative behaviours thought to characterise the 'origins of modern humans'. Now, claims for earlier manifestations of such innovations from a wider geographic range are more favourably received, albeit often fiercely challenged as the case for Pyrenean Neanderthal 'art' shows (White et al. 2020). This change in intellectual thinking does not, however, alter the strict requirements for a successful assertion of earlier intentionality by non-sapiens species. We should also note that stone, despite its ubiquity in early human evolutionary contexts, is a recalcitrant material not easily directly dated whether in the form of walling, artefact manufacture or potentially meaningful markings. The stakes are high but the demands are no less so.

      Why are the markings not natural? Berger and co-authors seem to find support for the artefactual nature of the markings in their location along a passage connecting chambers in the underground Rising Star Cave system. The presumption is that the hominins passed by the marked panel frequently. I recognise the thinking but the argument is weak. More confidently they note that "In previous work researchers have noted the limited depth of artificial lines, their manufacture from multiple parallel striations, and their association into clear arrangement or pattern as evidence of hominin manufacture (Fernandez-Jalvo et al. 2014)". The markings in the Rising Star Cave are said to be shallow, made by repeated grooving with a pointed stone tool that has left striations within the grooves and to form designs that are "geometric expressions" including crosshatching and cruciform shapes. "Composition and ordering" are said to be detectable in the set of grooved markings. Readers of this and their texts will no doubt have various opinions about these matters, mostly related to rather poorly defined or quantified terminology. I reserve judgement, but would draw little comfort from the similarities among equally unconvincing examples of early, especially very early, 'designs'. Two or even three half-convincing arguments do not add up to one convincing one.

      The authors draw our attention to one very interesting issue: given the extensive grooving into the dolomite bedrock by sharp stone objects, where are these objects? Only one potential 'lithic artefact' is reported, a "tool-shaped rock [that] does resemble tools from other contexts of more recent age in southern Africa, such as a silcrete tool with abstract ochre designs on it that was recovered from Blombos Cave (Henshilwood et al. 2018)", also figured by Berger and colleagues. A number of problems derive from this comparison. First, 'tool-shaped rock' is surely a meaningless term: in a modern toolshed 'tool-shaped' would surely need to be refined into 'saw-shaped', 'hammer-shaped' or 'chisel-shaped' to convey meaning? The authors here seem to mean that the Rising Star Cave object is shaped like the Blombos painted stone fragment. But the latter is a painted fragment, not a tool and so any formal similarity is surely superficial and offers no support to the 'tool-ness' of the Rising Star Cave object. Does this mean that Homo naledi took (several?) pointed stone tools down the dark passageways, used them extensively and, whether worn out or still usable, took them all out again when they left? Not impossible, of course. And the lighting?

      The authors rightly note that the circumstance of the markings "makes it challenging to assess whether the engravings are contemporary with the Homo naledi burial evidence from only a few metres away" and more pertinently, whether the hominins did the markings. Despite this honest admission, they are prepared to hypothesise that the hominin marked, without, it seems, any convincing evidence. If archaeologists took juxtaposition to demonstrate authorship, there would be any number of unlikely claims for the authorship of rock paintings or even stone tools. The idea that there were no entries into this Cave system between the Homo naledi individuals and the last two decades is an assertion, not an observation, and the relationship between hominins and designs no less so. In fact, the only 'evidence' for the age of the markings is given by the age of the Homo naledi remains, as no attempt at the, admittedly very difficult, perhaps impossible, task of geochronological assessment, has been made.

      The claims relating to artificiality, age and authorship made here seem entangled, premature and speculative. Whilst there is no evidence to refute them, there isn't convincing evidence to confirm them.

      References:

      • Davidson, I. 2020. Marks, pictures and art: their contribution to revolutions in communication. Journal of Archaeological Method and Theory 27: 3 745-770.

      • Henshilwood, C.S. et al. 2018. An abstract drawing from the 73,000-year-old levels at Blombos Cave, South Africa. Nature 562: 115-118.

      • Rodriguez-Vidal, J. et al. 2014. A rock engraving made by Neanderthals in Gibralter. Proceedings of the National Academy of Sciences.

      • White, Randall et al. 2020. Still no archaeological evidence that Neanderthals created Iberian cave art.

    1. Reviewer #3 (Public Review):

      This paper provides new information on the Dinaledi Chamber at the Rising Star Cave System. In short, a previously excavated area was expanded and resulted in the discovery of a cluster of bones appearing to be of one individual, a second similar cluster, and a third cluster with articulated elements (though with several individuals). Two of these clusters are argued to be intentionally buried individuals (the third one has not been investigated) and thus Homo naledi not only placed conspecifics in deep and hard to reach parts of caves but also buried them (apparently in shallow graves). This would be the oldest evidence of intentional burial. The main issue with the paper is that the purported burials were not fully excavated. Two are still in the ground, and one was removed in blocks but left unexcavated. As burials are mostly about sediments, it means the authors are lacking important lines of evidence. Instead, they bring other lines of argument as outlined below. While their preferred scenario is possible, there are important issues with the evidence as presented and they are severely hampered by the lack of detailed archaeological and geoarchaeological information both from the specific skeletal contexts and more generally from the chamber (because in fact the amount of excavation conducted here is still quite limited in scope). I also found that while the presentations of the various specialists in the team was quite good, the integration of these contributions into the main text was not. In particular, the geology of the cave system and the chamber need (especially what is known of the depositional and post-depositional processes) need to be better integrated into the presentation of the archaeology and the interpretation of the finds.

      Often times the presence of articulated or mostly articulated skeletons is used to argue for intentional burial. This argument, however, is based on the premise that if not buried, these skeletons would have otherwise become disarticulated. Normally disarticulation would happen as a result of subsequent use of the site by hominins (e.g. purported burials in Neandertal cave sites) or by carnivores scavenging the body. Indeed this latter point is why bodies are buried so deeply in many Western societies (i.e. beyond the reach and smell of carnivores). Bodies can also be disarticulated by natural processes of deposit and erosion.

      However, here in the case of the Dinaledi Chamber, we apparently don't have any of these other processes. The chamber was not used by carnivores and it was not a living area where H. naledi would have frequently returned and cleared out the space. As for depositional processes, it is more complex, but it is clear from Wiersma et al. that there is a steady, constant movement of these sediments towards drains. They also think that this process can account for the mix of articulated and non-articulated elements in the cave. Importantly, that same paper makes the argument that the formation of these sediments is not the result of water movement and that the cave has been dry since the formation of this deposit. So bodies lying on the surface and slowly covered by the formation of the deposit and slowly moving towards the drains could perhaps account for the pattern observed, meaning burial is not needed to account for articulations (note that more information on fabrics would be good in this context - orientation analysis of surface finds or of excavated finds is either completely lacking or minimal - see figure 13b and c report orientations on 79 bones of unknown context that appear to show perhaps elevated plunge angles and some slightly patterning in bearing but there is no associated statistics or text explaining the significance).

      So, unless the team can provide some process that would have otherwise disarticulated these skeletons after the bodies arrived here and decomposed, their articulated state is not evidence of burial (no more than finding an articulated or mostly articulated bear skeleton deep in a European cave would suggest that it was buried).

      As for the elemental analysis, what I understood from the paper is that the sediment associated with bones is different from the sediment not associated with bones. It is therefore unsurprising that the sediment associated with the reported skeletons clusters with sediments with bones. The linking argument for why this makes this sediment pit fill is unclear to me. Perhaps it is there, but as written I didn't follow it.

      What the elemental analysis could suggest, I think, is that there has not been substantial reworking of the sediments (as opposed to the creep suggested by Wiersma et al.) since the bones leached these minerals into the sediment. What I don't know, and what is not reported, is how long after deposition we can expect the soil chemistry to change. If this elemental analysis were extended in a systematic way across the chamber (both vertically and horizontally) after more extensive excavations, I could see it perhaps being useful for better understanding the site formation processes and depositional context. As it is now, I did not see the argument in support of a burial pit.

      The other line of evidence here is that some bones are sediment supported. The argument here is that when a body decomposes, bones that were previously held in place by soft tissues will be free to move and will shift their position. How the bones shift will differ depending on whether the body is surrounded by matrix (as they argue here in an excavated burial pit) or whether it is in the open (say, for instance, in a coffin) (and there are other possibilities as well - for instance wrapped in a shroud). Experiments have also shown the order in which the tendons, for instance, decompose and therefore which bones are likely to be free to move first or last.

      I will note that this literature is poorly cited. I think the only two papers cited for how bodies decompose are Roksandic 2002 and Mickleburgh and Wescott 2019. The former is a review paper that summarizes a great many contexts that are clearly not appropriate here, and it generally makes the point that it is difficult to sort out, and it notes that progressively filled is an additional alternative to not buried/buried. The other looks at experimental data of bodies decomposing without being buried. In the paper here, this citation is used to argue that the body must have been buried. I don't see the linking argument at all. And the cited paper is mostly about how complicated it is to figure this all out and how many variables are still unaccounted for (including the initial positioning of the body and the consumption of the body by insects - something that is attested to at Naledi - plus snails - see not just Val but also Wiersma et al. and I think the initial Dirk et al. paper).

      So the team here instead simply speaks of how the body decomposes in burials as if it is known. For the Feature 1 skeleton, the authors note that the ribs are "apparently" sediment supported and that a portion of the partial cranium is vertical or subvertical and sediment supported. For both of these, the figures show it very poorly. We really have to take their word for it. Second, I would have liked to have seen some reference and comparison to the literature for how the ribs should be in sediment burial cases. For the cranium, seems like a broken cranium resting on a surface will have vertical aspects regardless of sediment support. To the contrary, the orientation of the cranium will change depending on whether there is sediment holding it in place or not. But that argument is not made here. It is very hard from the figures to have a detailed idea of how these skeletons are oriented in the sediments, to know which elements are in articulation, which are missing, etc.

      In the case of the Hill Antechamber Feature, an additional argument is made about the orientation of the finds in relation to the natural stratigraphy in this location. The team argues that the skeleton is lying more horizontally than the sediments and that in fact the foot is lying against the slope. First, there is no documentation of the slope of the layers here (e.g. a stratigraphic profile with the layers marked or a fabric analysis). There is a photo in the SI that says it shows sloping, but it needs some work. Second, this skeleton was removed in three blocks and then scanned. So the position of the skeleton is being worked out separate from its context. This is doable, but I would have liked to have seen some mention of how the blocks were georeferenced in the field and then subsequently in the lab and of how the items inside the block (i.e. the data coming from the CT scanner) were then georeferenced. I can think of ways I would try to do this, but without some discussion of this critical issue, the argument presented in Figure 10c is difficult to evaluate. Further, even if we accept this work, it is hard for me to see how the alignment of the foot is 15 degrees opposite the slope (the figure in the SI is better). It is also hard to understand the argument that the sediment separating the lower limb from the torso means burial. The team gives the explanation that if the body was in an open pit it would have been flat with no separation. Maybe. I mean I guess if the pit was flat. But there is no evidence here of a pit (at all). And what if the body was stuffed down the chute and was resting on a slope and covered with additional sediments from the chute (or additional bodies) as it decomposed? It seems that this should be the starting point here rather than imagining a pit.

      One of the key pieces of evidence for demonstrating deliberate burial is the recognition of a pit. Pits can be identified because of the rupture they create in the stratigraphy when older sediments are brought to the surface, mixed, and then refilled into the pit with a different color, texture, compaction, etc. In some homogenous sediments a pit can be hard to detect and in some instances post-depositional processes (e.g. burrowing) can blur the distinction between the pit and the surrounding sediments. But the starting point of any discussion of deliberate burial has to be the demonstration of a pit. And I don't see it here. It might just be that the figures need to be improved. But I am skeptical because the team has taken the view that these finds can't be excavated. While I appreciate the scanning work done on the Antechamber find, it is not the same as excavating. Same comment for Features 1 and 2.

      In short, my view is that they have an extremely interesting dataset. That H. naledi buried their dead here can't be excluded based on the data, but neither is it supported here. My view is that this paper is premature and that more excavation and the use of geoarchaeological techniques (especially micromorphology) are required to sort this out (or go a long way towards sorting it out).

    1. Reviewer #3 (Public Review):

      This study explores how condensin and telomere proteins cooperate to facilitate sister chromatid disjunction at chromosome ends during anaphase. Building upon previous results published by the same group (Reyes et al. 2015, Berthezene et al. 2020), the authors demonstrate that condensin is essential for sister telomere disjunction in anaphase in fission yeast. The primary role of condensin appears to be counteracting cohesin, which holds sister telomeres together. Furthermore, condensin is found to be enriched at telomeres, and this enrichment partially relies on Taz1, the principal telomere factor in S. pombe. The loss of Taz1 does not cause an obvious defect in sister telomere disjunction, which prevents drawing strong conclusions about its role in this process.

    1. Reviewer #3 (Public Review):

      In this study, Gadani et al. induced EAE in SJL/J mice and performed a comprehensive spatial transcriptomic analysis in areas of meningeal inflammation during the relapse phase of the disease. The authors found specific enrichment in spatial gene signatures (cluster 11) in the regions of increased contrast-enhancement by MRI (where meningeal extravasation of activated immune cells is observed) that overlap with signatures in the adjacent brain parenchyma, namely the thalamus. Several pathways were similarly upregulated in the meningeal-associated cluster 11 and adjacent parenchymal clusters (like adaptive mediated immunity, and antigen processing and presentation), suggestive of a "leakage" of inflammatory mediators from the meninges into the brain during the re-activation of disease. The tested hypothesis, as well as the data presented in this study, is quite interesting and novel.

    1. Reviewer #3 (Public Review):

      It is well known that as seasonal day length increases, molecular cascades in the brain are triggered to ready an individual for reproduction. Some of these changes, however, can begin to occur before the day length threshold is reached, suggesting that short days similarly have the capacity to alter aspects of phenotype. This study seeks to understand the mechanisms by which short days can accomplish this task, which is an interesting and important question in the field of organismal biology and endocrinology.

      The set of studies that this manuscript presents is comprehensive and well-controlled. Many of the effects are also strong and thus offer tantalizing hints about the endo-molecular basis by which short days might stimulate major changes in body condition. Another strength is that the authors put together a compelling model for how different facets of an animal's reproductive state come "on line" as day length increases and spring approaches. In this way, I think the authors broadly fulfill their aims.

      I do, however, also think that there are a few weaknesses that the authors should consider, or that readers should consider when evaluating this manuscript. First, some of the molecular genetic analyses should be interpreted with greater caution. By bioinformatically showing that certain DNA motifs exist within a gene promoter (e.g., FSHbeta), one is not generating robust evidence that corresponding transcription factors actually regulate the expression of the gene in question. In fact, some may argue that this line of evidence only offers weak support for such a conclusion. I appreciate that actually running the laboratory experiments necessary to generate strong support for these types of conclusions is not trivial, and doing so may even be impossible. I would therefore suggest a clear admission of these limitations in the paper.

      Second, I have another issue with the interpretation of data presented in Figure 3. The data show that FSHbeta increases in expression in the 8Lext group, suggesting that endogenous drivers likely act to increase the expression of this gene despite no change in day length. However, more robust effects are reported for FSHbeta expression in the 10v and 12v groups, even compared to the 8Lext group. Doesn't this suggest that both endogenous mechanisms and changes in day length work together to ramp up FSHbeta? The rest of the paper seemed to emphasize endogenous mechanisms and gloss over the fact that such mechanisms likely work additively with other factors. I felt like there was more nuance to these findings than the authors were getting into.

      Third, studies 1 - 3 are well controlled; however, I'm left wondering how much of an effect the transitions in day length might have on the underlying molecular processes that mediate changes in body condition. While the changes in day length are themselves ecologically relevant, the transitions between day length states are not. How do we know, for example, that more gradual changes in day length that occur over long timespans do not produce different effects at the levels of the brain and body? This seemed especially relevant for study 3, where animals experience a rather sudden change in day length. I recognize that these experimental methods are well described in the literature, and they have been used by endocrinologists for a long time; nonetheless, I think questions remain.

    1. Reviewer #3 (Public Review):

      In this manuscript, Touray et al investigate the mechanisms by which PIP5Pase and RAP1 control VSG expression in T. brucei and demonstrate an important role for this enzyme in a signalling pathway that likely plays a role in antigenic variation in T. brucei.

      The methods used in the study are rigorous and well-controlled. The authors convincingly demonstrate that RAP1 binds to PI(3,4,5)P3 through its N-terminus and that this binding regulates RAP1 binding to VSG expression sites, which in turn regulates VSG silencing. Overall their results support the conclusions made in the manuscript.

      There are a few small caveats that are worth noting. First, the analysis of VSG derepression and switching in Figure 1 relies on a genome that does not contain minichromosomal (MC) VSG sequences. This means that MC VSGs could theoretically be misassigned as coming from another genomic location in the absence of an MC reference. As the origin of the VSGs in these clones isn't a major point in the paper, I do not think this is a major concern, but I would not over-interpret the particular details of switching outcomes in these experiments.

      The authors state that "our data imply that antigenic variation is not exclusively stochastic." I am not sure this is true. While I also favor the idea that switching is not exclusively stochastic, evidence for a signaling pathway does not necessarily imply that antigenic variation is not stochastic. This pathway could be important solely for lifecycle-related control of VSG expression, rather than antigenic variation during infection. Nevertheless, these data are critical for establishing a potential pathway that could control antigenic variation and thus represent a fundamental discovery.

      Another aspect of this work that is perhaps important, but not discussed much by the authors, is the fact that signalling is extremely poorly understood in T. brucei. In Figure 1B, the RNA-seq data show many genes upregulated after expression of the Mut PIP5Pase (not just VSGs). The authors rightly avoid claiming that this pathway is exclusive to VSGs, but I wonder if these data could provide insight into the other biological processes that might be controlled by this signaling pathway in T. brucei.

      Overall, this is an excellent study that represents an important step forward in understanding how antigenic variation is controlled in T. brucei. The possibility that this process could be controlled via a signalling pathway has been speculated for a long time, and this study provides the first mechanistic evidence for that possibility.

    1. Reviewer #3 (Public Review):

      Bierman et al. present a novel statistical framework for examining the subcellular localisation of RNA molecules. Subcellular Patterning Ranked Analysis With Labels, SPRAWL, uses the data available in multiplexed single-cell imaging datasets to assign four metrics of localisation patterns to RNA at a gene per cell level. These easy-to-understand scores, ranging from -1 to 1, can be averaged to detect cell-type specific spatial patterns or used in tandem with tools for RNA 3' UTR length or splicing state to determine the correlation between subcellular localisation and RNA isoforms. Such quantitive association between RNA isoforms and localisation provides a useful tool to determine candidate genes for future studies.

      The peripheral and central scores indicate the proximity of RNA molecules to the cell boundary and centre of the cell respectively in relation to other RNA present in the cell. Whilst understanding whether a gene tends to be localised to the cellular membrane is important, it is unclear what biological benefits the central metric gives compared to high "anti-peripheral" scores considering that no single organelle (eg. the nucleus) is located specifically at the centre of the cell in all cell-types.

      The punctate and radial patterning scores provide information on the spatial aggregation of RNA molecules of a given gene within a cell. Whilst the punctate score is easy to understand as simply the distance between RNA, the radial score, the angle between RNA, is harder to understand from the main text and would benefit from a schematic showing how this is in respect to the cell-boundary centroid.

      Despite endeavouring to create a robust statistical measure of RNA subcellular localisation, this paper is full of inconsistencies. Values (eg. Pearson correlation coefficient values, number of significant genes, number of total genes) and names (eg. cell types, gene names) stated throughout the main text and figures/table do not match repeatedly and without fixing these disparities, the conclusions from this paper are hard to believe.

    1. Reviewer #3 (Public Review):

      The article by Ma et al pursues the previous work of the Schekman group, exploring the mechanisms of targeting of miRNAs into extracellular vesicles (EVs), or possibly exosomes, in HEK293 and U2OS cells. The authors had identified YBX1 as an RNA-binding protein required for the sorting of miR223 into CD63-expressing small EVs, probably mainly exosomes. Here they further observed that YBX1 directly binds miR223, which also binds to another protein, YBAP1, localized in mitochondria, where it sequesters miR223, thus preventing its targeting to MVBs' intraluminal vesicles. They observe the association of YBX1-containing P-bodies in the cytoplasm with mitochondria and with enlarged Rab5-endosomes and propose that this step is required for the exchange of miR223 for its loading into MVBs intraluminal vesicles and future exosomes.

      The biochemical parts of the article, with quantitative experiments to decipher the molecular interactions of YBX1 and YBAP1 with miR223, are nicely performed and convincing. By contrast, the parts on the involvement of YBX1 and of YBAP1 in the release of miR223 in EVs or exosomes are more correlative than demonstrative and lack some controls. In particular, it is far-fetched to conclude from the observed movement (which may be serendipitous) of 2 P-bodies between mitochondria and enlarged endosomes (without any visualization of the miR) that this movement may be instrumental in the transfer of miR223 between mitochondria and putative exosomes (figures 6 and model in figure 7).

      The experiments designed to evidence the mechanisms of miR223 release in EVs are also not sufficiently controlled and analysed to really support the interpretations. And the EV isolation steps are not performed in a way that supports the actual exosomal nature (i.e. exclusive origin from multivesicular endosome) of the EV analysed.

      Another experimental weakness is that the authors make strong conclusions on MVBs and exosomes when they only analyse artificially-enlarged endosomes induced by overexpression of mutant Rab5. Although this approach has been used previously and shown CD63 in these induced enlarged compartments, it is an artificial blocking of normal endosomal trafficking, and may not reflect the situation of intracellular trafficking of miR223 in normal cells.

    1. Reviewer #3 (Public Review):

      Sarkari et al. describe the effects of TTFields on inter-cellular communication structures called tunneling nanotubes in malignant pleural mesothelioma cells. Recent studies have implicated these F-actin-based nanotubes in promoting malignant transformation and biology by allowing long-range communications between malignant cells. The authors suggest that TTFields disrupt these structures by impacting the expression of genes involved in nanotube formation and cell proliferation. Although TTFields are thought to affect tubulin-based structures, recent studies suggest that TTFields also impact actin-based structures. Therefore, the authors' findings are in keeping with this new understanding. They also found that TTFields upregulated marker genes in immunity. This is one of the first studies that implicate TTFields in these tunneling nanotube structures. Overall, the study adds to our understanding of TTFields on various cellular structures. However, conclusions are only partially supported by the data presented. The study is largely descriptive and there are many areas that need to be addressed to substantively improve the premise and rigors and strengthen the conclusions.

    1. Reviewer #3 (Public Review):

      The authors investigate the potential effect of OGlcNacylation on the activity of the DNA methyltransferase DNMT1.

      Some results that are convincingly obtained include:<br /> - There is more overall OGlcNacylation when Glucose concentration in the culture medium or the feed is high;<br /> - DNMT1 is OGlcNacylated, and more so in high glucose or on rich chow;<br /> - The position S878 can be OGlcNacylated;<br /> - The activity of transfected DNMT1 is decreased in high glucose conditions. This effect is lessened when S878 is mutated to A or D.

      Some results that are suggested but not fully backed by experimental data include:<br /> - This process happens to the endogenous protein under physiologically relevant conditions;<br /> - This process is responsible for changes in DNA methylation, leading to changes in gene expression, leading to increased ROS and increased apoptosis.

      Studying the connection between cellular metabolism and epigenetic phenomena is interesting. However, I feel that the article falls short of its aims because of the limits of the experimental system, some missing controls, and some data overinterpretation.

    1. Reviewer #3 (Public Review):

      This US study presents findings from an online survey and in-person interviews of healthcare providers regarding themes associated with cervical screening in federally qualified health centres (FQHCs). The study provides insights during the post-acute phase of the pandemic into a range of areas, including perceived changes in the provision of cervical cancer screening services and the impact of the pandemic, staffing and systems barriers to cervical cancer screening, strategies for tracking missed screens and catch-ups, follow-up of abnormal screening results, as well as attitudes towards HPV self-sampling. Results indicate persisting pandemic-related impacts on patient engagement and staffing, as well as system barriers to effective screening, catch-up of missed screens and follow-ups. Taken together, these issues may lead to increases in cervical cancer in the long-term in populations serviced by these centres, if measures are not taken to adequately support them. Participants were recruited from various regions in the US, however, the study was not conducted using a nationally-representative sample. Although highlighted issues are informative, findings cannot be generalised and larger studies are warranted in the future to monitor cervical screening provision and outcomes in FQHCs.

    1. Reviewer #3 (Public Review):

      This study presents a new pipeline for mapping the auditory-language pathway in children with profound congenital sensorineural hearing loss (SNHL), focusing on those with inner ear malformations and/or cochlear nerve deficiency (IEM&CND). Using structural and diffusional MRI, the researchers investigated the structural fiber properties of the auditory-language networks in affected children under six years old. Findings suggest that the language pathway is more sensitive to peripheral auditory than the central auditory pathway, emphasizing the need for early intervention to provide speech inputs. The study also proposes a comprehensive pre-surgical evaluation from the cochlea to the auditory-language network.

      Strengths:

      1. Investigating fiber properties across various brain network levels (from peripheral structures to central auditory and higher-level language pathways) using high-resolution diffusion imaging and an innovative pipeline.

      2. Evaluating presurgical fiber properties in two subgroups of SNHL children (cochlear implant and auditory brainstem implant candidates) to demonstrate the relationship between peripheral auditory structure damage and the development of auditory-language structural pathways.

      Weaknesses:

      1. Limited sample size: The study analyzed data from 13 SNHL children and 10 normal-hearing children, potentially restricting the validity and reproducibility of the findings, particularly in correlation results based on individual differences.

      2. Lack of speech and language behavioral measures: Although the researchers collected behavioral data post-CI/ABI surgery for most participants, no such data was reported. Consequently, the association between presurgical fiber measures and postsurgical outcomes remains unclear.

      3. Unclear practical implications: The relevance of the presurgical evaluation of the auditory-language network for surgical decision-making and prognosis estimation is not evident, as fiber measures may not correlate with behavioral outcomes.

    1. Reviewer #3 (Public Review):

      Summary:

      A useful and potentially powerful analysis of gene expression correlations across major organ and tissue systems that exploits a subset of 310 humans from the GTEx collection (subjects for whom there are uniformly processed postmortem RNA-seq data for 18 tissues or organs). The analysis is complemented by a Shiny R application web service.

      The need for more multisystems analysis of transcript correlation is very well motivated by the authors. Their work should be contrasted with more simple comparisons of correlation structure within different organs and tissues, rather than actual correlations across organs and tissues.

      Strengths and Weaknesses:

      The strengths and limitations of this work trace back to the nature of the GTEx data set itself. The authors refer to the correlations of transcripts as "gene" and "genetic" correlations throughout. In fact, they name their web service "Genetically-Derived Correlations Across Tissues". But all GTEx subjects had strong exposure to unique environments and all correlations will be driven by developmental and environmental factors, age, sex differences, and shared and unshared pre- and postmortem technical artifacts. In fact we know that the heritability of transcript levels is generally low, often well under 25%, even studies of animals with tight environmental control.

      This criticism does not comment materially detract for the importance and utility of the correlations-whether genetic, GXE, or purely environmental-but it does mean that the authors should ideally restructure and reword text so as to NOT claim so much for "genetics". It may be possible to incorporate estimates of chip heritability of transcripts into this work if the genetic component of correlations is regarded as critical (all GTEx cases have genotypes).

      Appraisal of Work on the Field:

      There are two parts to this paper: 1. "case studies" of cross-tissue/organ correlations and 2. the creation of an R/Shiny application to make this type of analysis much more practical for any biologist. Both parts of the work are of high potential value, but neither is fully developed. My own opinion is that the R/Shiny component is the more important immediate contribution and that the "case studies" could be placed in the context of a more complete primer. Or Alternatively, the case studies could be their own independent contributions with more validation.

    1. Reviewer #3 (Public Review):

      In this paper, the authors analyze a large previously published deep mutational scanning data set using a reference-free regression approach. They extract the contributions of single locus and epistatic effects to the functionality of the sequence (no, weak or strong transcription activation of two response elements). They find that pairwise epistasis plays a crucial and dominant role at creating functional sequences and at connecting the functional sequence space.

      I enjoyed reading the paper and the topic (role of epistasis at creating and connecting functional sequences; development of measures of epistasis) is very exciting to me. However, I found it difficult to judge the strength of the paper both because it is written in a rather dense and yet potentially redundant fashion (see comment 1) and because I was left with a number of questions upon reading. I will focus on conceptual questions in the following comments, since I am not able to judge the statistical approach in detail.

      1/ Regarding the biological result (importance of pairwise epistasis) I was wondering how potentially redundant the consecutive sections of the paper are. In which situation would the authors expect that pairwise epistasis does *not* play a crucial role for mutational steps, trajectories, or space connectedness, if it is dominant in the genotype-phenotype landscape? I would also appreciate an explanation of how much new biological results this paper delivers as compared with the paper in which the data were published (which I, unfortunately, cannot access at the moment of writing this report).

      2a/ Regarding the regression approach: I very much appreciate a reference-free approach to the estimation of epistasis. However, I would enjoy an explanation of how the results would have been (potentially) different if a reference-based approach was used, and how it compares with other reference-free approaches to estimating epistasis (e.g., linear regression or the gamma statistics of Ferretti et al. 2015).

      2b/ When comparing the outcomes with and without epistasis, I understood that the authors compare the estimated "full model" with the outcome if epistatic effects were ignored - but without a new estimation of main effects if epistasis is ignored. Wouldn't that be a more fair comparison?

      2c/ Where do the authors see the applicability of their approach to data beyond those analyzed in the present study? What are the requirements to use it? Does it only work for combinatorially complete landscapes? I did not have a chance to look at the code - how easily could other researchers apply the approach to their data?

    1. Reviewer #3 (Public Review):

      This work provides a novel design of implantable and high-density EMG electrodes to study muscle physiology and neuromotor control at the level of individual motor units. Current methods of recording EMG using intramuscular fine-wire electrodes do not allow for isolation of motor units and are limited by the muscle size and the type of behavior used in the study. The authors of myomatrix arrays had set out to overcome these challenges in EMG recording and provided compelling evidence to support the usefulness of the new technology.

      Strengths:

      • They presented convincing examples of EMG recordings with high signal quality using this new technology from a wide array of animal species, muscles, and behavior.<br /> • The design included suture holes and pull-on tabs that facilitate implantation and ensure stable recordings over months.<br /> • Clear presentation of specifics of the fabrication and implantation, recording methods used, and data analysis

      Weaknesses:

      • The justification for the need to study the activity of isolated motor units is underdeveloped. The study could be strengthened by providing example recordings from studies that try to answer questions where isolation of motor unit activity is most critical. For example, there is immense value for understanding muscles with smaller innervation ratio which tend to have many motor neurons for fine control of eyes and hand muscles.

    1. Reviewer #3 (Public Review):

      The manuscript describes new ligand-bound structures within the larger bile acid sodium symporter family (BASS). This is the primary advance in the manuscript, together with molecular simulations describing how sodium and the bile acids sit in the structure when thermalized. What I think is fairly clear is that the ligands are more stable when the sodiums are present, with a marked reduction in RMSD over the course of repeated trajectories. This would be consistent with a transport model where sodium ions bind first, and then the bile acid binds, followed by a conformational change to another state where the ligands unbind.

      While the authors mention that BASS transporters are thought to undergo an elevator transport mechanisms, this is not tested here. In my reading, all the crystal structures describe the same conformational state, and the simulations do not make an attempt to induce a transition on accessible simulation timescales. Instead, there is a morph between two states where different substrates are bound, which induces a conformational change that looks unrelated to the transport cycle.

      Instead, the focus is on what kinds of substrates bind to this transporter, interrogating this with isothermal calorimetry together with mutations. With a Kd in the micromolar range, even the best binder, pantoate, actually isn't a particularly tight binder in the pharmaceutical sense. For a transporter, tight binding is not actually desirable, since the substrate needs to be able to leave after conformational change places it in a position accessible to the other side.

      There is one really important point that readers and authors should be aware of. In Figure 2A, the names are not consistent with the chemical structure. "-ate" denotes when a carboxylic acid is in the deprotonated form, creating a charged carboxylate. What is drawn is pantoic acid, ketopantoic acid, and pantoethenic acid. Less importantly, the wedges and hashes for the methyl group are arguably not appropriate, since the carbon they are attached to is not a chiral center. For the crystallization, this makes no difference, since under near-neutral pKas the carboxylic acid will spontaneously deprotonate, and the carboxylate form will be the most common. However, if the structures in Figure 2A were used for classical molecular simulation, that would be a big problem, since now that would be modeling the much rarer neutral form rather than the charged state. I am reasonably sure based on Figure 5 that the MD correctly modeled the deprotonated form with a carboxylate, but that is inconsistent with Figure 2A. Otherwise, the structure and simulation analysis falls into the mainstream of modern structural biology work.

    1. Reviewer #3 (Public Review):

      The authors investigate the mechanisms by which ISG65 and C3 recognize and interact with each other. The major strength is the identification of eco-site by determining the cryoEM structure of the complex, which suggests new intervention strategies. This is a solid body of work that has an important impact on parasitology, immunology, and structural biology.

    1. Reviewer #3 (Public Review):

      The manuscript describes a combination of in vitro and in vivo results implicating Dyrk1a in the regulation of mTORC. Particular strengths of the data are this combination of cell and whole animal (drosophila) based studies. However, most of the experiments seem to lack a key additional experimental condition that could increase confidence in the authors' conclusions. Overall some tantalizing data is presented. However, there are several issues that should be clarified or otherwise addressed with additional data.

      1. In Figure 1G, why not test overexpression levels of Dyrk1a via western rather than only looking at the RNA levels?

      2. In Figure 2, while there is clearly TSC1 protein in the Dyrk1a and FLAG-Dyrk1a IPs that supports an interaction between the proteins, it would be good to see the reciprocal IP experiment wherein TSC1 or TSC2 are pulled down and then the blot probed for Dyrk1a.

      3. Figures 3 A and D tested the effects of Dyrk1a knockdown using different methods in different cell lines. This is a reasonable approach to ascertain the generalizability of findings. However, each experiment is performed differently. For example, in 3A, the authors found no difference in baseline pS6, so they did a time course of treatment to induce phosphorylation and found differences depending on Dyrk1a expression. In 3D, they only show baseline effects from the CRISPr knockdown. Why not do the time course as well for consistency? Also, why the inconsistency in approaches wherein one shows baseline effects and the other does not? The authors could also consider the pharmacologic inhibition of Dyrk1a activity as well.

      4. In Figure 4, RHEB overexpression increases cell size in both Dyrk1a wt and Dyrk1a shRNA treated cells, although the magnitude of the effect appears reduced in Dyrk1a shRNA cells. However, there is the possibility here that RHEB acts independently of Dyrk1a. Why not also do the experiment of Figure 1 wherein Dyrk1a is overexpressed and then knockdown RHEB in that context? If the hypothesis is supported, then RHEB knockdown should eliminate the cell size effect of Dyrk1a overexpression.

      5. The discussion should incorporate relevant findings from other models, such as Arabidopsis. Barrada et al., Development (2019), 146 (3).

    1. Reviewer #3 (Public Review):

      A detailed understanding of how membrane receptor guanylyl cyclases (mGC) are regulated has been hampered by the absence of structural information on the cytoplasmic regions of these signaling proteins. The study by Caveney et al. reports the 3.9Å cryo-EM structure of the human mGC cyclase, GC-C, bound to the Hsp90-Cdc37 chaperone complex. This structure represents a first view of the intracellular functional domains of any mGC and answers without doubt that Hsp90-Cdc37 recognizes mGCs via their pseudokinase (PK) domain. This is the primary breakthrough of this study. Additionally, the new structural data reveals that the manner in which Hsp90-Cdc37 recognizes the GC-C PK domain C-lobe is akin to how kinase domains of soluble kinases docks to the chaperone complex. This is the second major finding of this study, which provides a concrete framework to understand, more broadly, how Hsp90-Cdc37 recruits a large number of other diverse client proteins containing kinase or pseudokinase domains. Finally, the Hsp90-Cdc37-GC-C structure offer clues as to how GC-C may be regulated by phosphorylation and/or ubiquitinylation by serving as a platform for recruitment of PP5 and/or E3 ligases.

    1. Reviewer #3 (Public Review):

      The authors set out to demonstrate the utility of functional ultrasound for evaluating changes in brain hemodynamics elicited acutely and subacutely by the middle cerebral artery occlusion model of ischemic stroke in awake rats.

      Functional ultrasound affords a distinct set of tradeoffs relative to competing imaging modalities. Acclimatization of rats for awake imaging has proven difficult with most, and the high quality of presented data in awake rats is a major achievement. The major weakness of the approach is in its being restricted to single-slice acquisitions, which also complicates the registration of acquisition across multiple imaging sessions within the same animal. Establishing that awake imaging represents an advancement in relation to studies under anesthesia hinges upon the establishment of the level of stress experienced by the animals in the course of imaging, i.e., requires providing data on the assessment of stress over the course of these long imaging sessions. This is particularly significant given how significant a stressor physical restraint has been established to be in rodent models of stress. Furthermore, assessment of the robustness of these measurements is of particular significance for supporting the wide applicability of this approach to preclinical studies of brain injury: the individual animal data (effect sizes, activation areas, kinetics) should thus be displayed and the statistical analysis expanded. Both within-subject, within/across sessions, and across-subjects variability should be evaluated. Thoughtful comments on the relationship between power doppler signal and cerebral blood volume are important to include and facilitate comparisons to studies recording other blood volume-weighted signals. Finally, the contextualization of the observations with respect to other studies examining acute and subacute changes in brain hemodynamics post focal ischemic stroke in rats is needed. It is also quite helpful, for establishing the robustness of the approach, when the statistical parametric maps are shown in full (i.e. unmasked).

    1. Reviewer #3 (Public Review):

      In this manuscript, Rossato and colleagues present a method for real-time decoding of EMG into putative single motor units. Their manuscript details a variety of decision points in their code and data collection pipeline that lead to a final result of recording on the order of ~10 putative motor units per muscle in human males. Overall the manuscript is highly restricted in its potential utility but may be of interest to aficionados. For those outside the field of human or nonhuman primate EMG, these methods will be of limited interest.

      Notes<br /> 1. Artificial data should be used with this method to provide ground truth performance evaluations. Without it, the study assumptions are unchallenged and could be seriously flawed.

      2. From the point of view of a motor control neuroscientist studying movement in animals other than humans or non-human primates, the title was misleadingly hopeful. The use case presented in this study requires human participants to perform isometric contractions, facilitating spatially redundant recordings across the muscle for the algorithm to work. It is unclear whether these methods will be of utility to use cases under more physiological conditions (ie. dynamic movement).

      3. The text states that "EMG signals recorded with an array of electrodes can be considered and instantaneous mixture of the original motor unit spike trains and their delayed versions." While this may be a true statement, it is not a complete statement, since motor units at distal sites may be shared, not shared, or novel. It was not clear to me whether the diversity of these scenarios would affect the performance of the software or introduce artifacts. In other words, if at site 1 you can pick up the bulk signal of units 1,2,3,4; at site two you pick up the signals of units 2,3,4,5 and site three you pick up the signal of units 3,4,5,6, what does the algorithm assume is happening and what does it report and why?

      4. I could not fully appreciate the performance gap solved by the current methods. What was not achievable before that is now achievable? The 125 ms speed of deconvolution? What was achievable before? Intro text around ln 85 states that 'most of the current implementations of this approach rely on offline processing, which restricts its ability to be used..." but no reference is provided here about what the non 'most' of can achieve.

      5. Relatedly, it would have been nice to see a proof of concept using real-time feedback for some kind of biofeedback signal. If that is the objective here, why not show us this? I found the actual readout metrics of performance rather esoteric. They may be of interest to very close experts so I will defer to them for input.

      6. I was disappointed to see that only male participants are used because of some vague statement that 'it is widely known in the field' that more motor units can be resolved in males, without thorough referencing. It seems that the objective of the algorithm is the speed of analysis, not the number of units, which makes the elimination of female participants not justified.

      7. Human curation is often used in spike sorting, but the description of criteria used in this step or how the human curation choices are documented is missing.

      8. The authors might try to add text to be more circumspect about the contributions of this method. I would recommend emphasizing the conceptual advances over the specifics of the performance of the algorithm since processor speed and implementation of the ideas in a faster environment (Matlab can be slow) will change those outcomes in a trivial way. Yet, much of the results section is very focused on these metrics.<br /> Minor<br /> Ln 115, "inversing" is not a word. "inverse" is not a verb<br /> Ln 186, typo, bioadhesive<br /> MVC should be defined on first use. It is currently defined on 3rd use or so.<br /> The term rate is used in a variety of places without units. Eg line 465 but not limited to that

    1. Reviewer #3 (Public Review):

      This paper analyses self-citation rates in the field of Neuroscience, comprising in this case, Neurology, Neuroscience and Psychiatry. Based on data from Scopus, the authors identify self-citations, that is, whether references from a paper by some authors cite work that is written by one of the same authors. They separately analyse this in terms of first-author self-citations and last-author self-citations. The analysis is well-executed and the analysis and results are written down clearly. There are some minor methodological clarifications needed, but more importantly, the interpretation of some of the results might prove more challenging. That is, it is not always clear what is being estimated, and more importantly, the extent to which self-citations are "problematic" remains unclear.

      When are self-citations problematic? As the authors themselves also clarify, "self-citations may often be appropriate". Researchers cite their own previous work for perfectly good reasons, similar to reasons of why they would cite work by others. The "problem", in a sense, is that researchers cite their own work, just to increase the citation count, or to promote their own work and make it more visible. This self-promotional behaviour might be incentivised by certain research evaluation procedures (e.g. hiring, promoting) that overly emphasise citation performance. However, the true problem then might not be (self-)citation practices, but instead, the flawed research evaluation procedures that emphasis citation performance too much. So instead of problematising self-citation behaviour, and trying to address it, we might do better to address flawed research evaluation procedures. Of course, we should expect references to be relevant, and we should avoid self-promotional references, but addressing self-citations may just have minimal effects, and would not solve the more fundamental issue.

      Some other challenges arise when taking a statistical perspective. For any given paper, we could browse through the references, and determine whether a particular reference would be warranted or not. For instance, we could note that there might be a reference included that is not at all relevant to the paper. Taking a broader perspective, the irrelevant reference might point to work by others, included just for reasons of prestige, so-called perfunctory citations. But it could of course also include self-citations. When we simply start counting all self-citations, we do not see what fraction of those self-citations would be warranted as references. The question then emerges, what level of self-citations should be counted as "high"? How should we determine that? If we observe differences in self-citation rates, what does it tell us?

      For example, the authors find that the (any author) self-citation rate in Neuroscience is 10.7% versus 15.9% in Psychiatry. What does this difference mean? Are psychiatrists citing themselves more often than neuroscientists? First author men showed a self-citation rate of 5.12% versus a self-citation rate of 3.34% of women first authors. Do men engage in more problematic citation behaviour? Junior researchers (10-year career) show a self-citation rate of about 5% compared to a self-citation rate of about 10% for senior researchers (30-year career). Are senior researchers therefore engaging in more problematic citation behaviour? The answer is (most likely) "no", because senior authors have simply published more, and will therefore have more opportunities to refer to their own work. To be clear: the authors are aware of this, and also take this into account. In fact, these "raw" various self-citation rates may, as the authors themselves say, "give the illusion" of self-citation rates, but these are somehow "hidden" by, for instance, career seniority.

      Again, the authors do consider this, and "control" for career length and number of publications, et cetera, in their regression model. Some of the previous observations then change in the regression model. Neuroscience doesn't seem to be self-citing more, there just seem to be junior researchers in that field compared to Psychiatry. Similarly, men and women don't seem to show an overall different self-citation behaviour (although the authors find an early-career difference), the men included in the study simply have longer careers and more publications.

      But here's the key issue: what does it then mean to "control" for some variables? This doesn't make any sense, except in the light of causality. That is, we should control for some variable, such as seniority, because we are interested in some causal effect. The field may not "cause" the observed differences in self-citation behaviour, this is mediated by seniority. Or is it confounded by seniority? Are the overall gender differences also mediated by seniority? How would the selection of high-impact journals "bias" estimates of causal effects on self-citation? Can we interpret the coefficients as causal effects of that variable on self-citations? If so, would we try to interpret this as total causal effects, or direct causal effects? If they do not represent causal effects, how should they be interpreted then? In particular, how should it "inform author, editors, funding agencies and institutions", as the authors say? What should they be informed about?

      The authors also "encourage authors to explore their trends in self-citation rates". It is laudable to be self-critical and review ones own practices. But how should authors interpret their self-citation rate? How useful is it to know whether it is 5%, 10% or 15%? What would be the "reasonable" self-citation rate? How should we go about constructing such a benchmark rate? Again, this would necessitate some causal answer. Instead of looking at the self-citation rate, it would presumably be much more informative to simply ask authors to check whether references are appropriate and relevant to the topic at hand.

      In conclusion, the study shows some interesting and relevant differences in self-citation rates. As such, it is a welcome contribution to ongoing discussions of (self) citations. However, without a clear causal framework, it is challenging to interpret the observed differences.

    1. Reviewer #3 (Public Review):

      The present study aims to investigate whether pain influences cortical excitability. To this end, heat pain stimuli are applied to healthy human participants. Simultaneously, TMS pulses are applied to M1 and TMS-evoked potentials (TEPs) and pain ratings are assessed after each TMS pulse. TEPs are used as measures of cortical excitability. The results show that TEP amplitudes at 45 msec (N45) after TMS pulses are higher during painful stimulation than during non-painful warm stimulation. Control experiments indicate that auditory, somatosensory, or proprioceptive effects cannot explain this effect. Considering that the N45 might reflect GABAergic activity, the results suggest that pain changes GABAergic activity. The authors conclude that TEP indices of GABAergic transmission might be useful as biomarkers of pain sensitivity.

      Pain-induced cortical excitability changes is an interesting, timely, and potentially clinically relevant topic. The paradigm and the analysis are sound, the results are mostly convincing, and the interpretation is adequate. The following clarifications and revisions might help to improve the manuscript further.

      1. Non-painful control condition. In this condition, stimuli are applied at warmth detection threshold. At this intensity, by definition, some stimuli are not perceived as different from the baseline. Thus, this condition might not be perfectly suited to control for the effects of painful vs. non-painful stimulation. This potential confound should be critically discussed.<br /> 2. MEP differences between conditions. The results do not show differences in MEP amplitudes between conditions (BF 1.015). The analysis nevertheless relates MEP differences between conditions to pain ratings. It would be more appropriate to state that in this study, pain did not affect MEP and to remove the correlation analysis and its interpretation from the manuscript.<br /> 3. Confounds by pain ratings. The ISI between TMS pulses is 4 sec and includes verbal pain ratings. Considering this relatively short ISI, would it be possible that verbal pain ratings confound the TEP? Moreover, could the pain ratings confound TEP differences between conditions, e.g., by providing earlier ratings when the stimulus is painful? This should be carefully considered, and the authors might perform control analyses.<br /> 4. Confounds by time effects. Non-painful and painful conditions were performed in a fixed order. Potential confounds by time effects should be carefully considered.<br /> 5. Data availability. The authors should state how they make the data openly available.

    1. Reviewer #3 (Public Review):

      In this manuscript, Magnuson and colleagues investigate the meiotic functions of ARID1A, a putative DNA binding subunit of the SWI/SNF chromatin remodeler BAF. The authors develop a germ cell specific knockout mouse model using Stra8-cre and observe that ARID1A-deficient cells undergo pachytene arrest, although due to inefficiency of the Stra8-cre system the mice retain ARID1A-expressing cells that yield sperm and allow fertility. Because ARID1A was found to accumulate at the XY body late in Prophase I, the authors suspected a potential role in meiotic silencing and by RNAseq observe significant misexpression of sex-linked genes that typically are silenced at pachytene. They go on to show that ARID1A is required for exclusion of RNA PolII from the sex body, consistent with a meiotic sex chromosome inactivation (MSCI) defect. The authors proceed to investigate the impacts of ARID1A on chromatin accessibility and H3.3 deposition genome-wide. H3.3 is known be regulated by ARID1A and is linked to silencing, and here the authors find that upon loss of ARID1A, overall H3.3 enrichment at the sex body as measured by IF failed to occur, but H3.3 was enriched specifically at transcriptional start sites of sex-linked genes that are normally regulated by ARID1A. The results suggest that ARID1A normally prevents H3.3 accumulation at target promoters on sex chromosomes and based on additional data, restricts H3.3 to intergenic sites. Finally, the authors present data implicating ARID1A and H3.3 occupancy in DSB repair, finding that ARID1A KO leads to a reduction in focus formation by DMC1, a key repair protein. Overall the paper covers a lot of ground, provides important new insights into the process of MSCI from the perspective of chromatin composition and structure, and raises many interesting questions. In general the paper is well written and the data are clear. Specific points to address are as follows:

      1. A challenge with the author's CKO model is the incomplete efficiency of ARID1A loss, due to incomplete CRE-mediated deletion. The authors effectively work around this issue, but they don't state specifically what percentage of CKO cells lack ARID1A staining. This information should be added. They refer to cells that retain ARID1A staining in CKO testes as 'internal controls' but this reviewer finds that label inappropriate. Although some cells that retain ARID1A won't have undergone CRE-mediated excision, others may have excised but possibly have delayed kinetics of deletion or ARID1A RNA/protein turnover and loss. Such cells likely have partial ARID1A depletion to different extents and therefore in some cases are no longer wild-type. In subsequent figures in which co-staining for ARID1A is done, it would be appropriate for the authors to specify if they are quantifying all cells from CKO testes, or only those that lack ARID1A staining.

      2. The authors don't see defects in a few DDR markers in ARID1A CKO cells and conclude that the role of ARID1A in silencing is 'mutually exclusive to DDR pathways' (p 12) and 'occurs independently of DDR signaling' (p30). The data suggest that ARID1A may not be required for DDR signaling, but do not rule out the possibility that ARID1A is downstream of DDR signaling (and the authors even hypothesize this on p30). The data provided do not justify the conclusion that ARID1A acts independently of DDR signaling.

      3. After observing no changes in levels or localization of H3.3 chaperones, the authors conclude that 'ARID1A impacts H3.3 accumulation on the sex chromosomes without affecting its expression or incorporation during pachynema.' It's not clear to this reviewer what the authors mean by this. Aside from the issue of not having tested DAXX or HIRA activity, are they suggesting that some other process besides altered incorporation leads to H3.3 accumulation and if so what process would that be?

      4. The authors find an interesting connection between certain regions that gained chromatin accessibility after ARID1A loss (clusters G1 and G3) and presence of the PRDM9 sequence motif. The G1 and G3 clusters also show DMC1 occupancy and H3K4me3 enrichment. However, an additional cluster with gained accessibility (G4) also shows DMC1 occupancy and H3K4me3 enrichment but unlike clusters G1 and G3 has modest H3.3 accumulation. The paper would benefit for additional discussion about the G4 cluster (which encompasses 960 peak calls). Is there any enrichment of PRDM9 sites in G4? If H3.3 exclusion governs meiotic DSBs, how does cluster G4 fit into the model?

      5. The impacts of ARID1A loss on DMC1 focus formation (reduced sex chromosome association) are very interesting and also raise additional questions. Are DMC1 foci on autosomes also affected during pachynema? The corresponding lack of apparent effect on RAD51 implies that breaks are still made and resected, enabling RAD51 filament formation. A more thorough quantitative assessment of RAD51 focus formation will be interesting in the long run, enabling determination of the number of break sites and the kinetics of repair, which the authors suggest is perturbed by ARID1A loss but don't directly test. It isn't clear how a nucleosomal factor (H3.3) would influence loading of recombinases onto ssDNA, especially if the alteration is not at the level of resection and ssDNA formation. Additional discussion of this point is warranted. Lastly, there currently are various notions for the interplay between RAD51 and DMC1 in filament formation and break repair, and brief discussion of this area and the implications of the new findings from the ARID1A CKO would strengthen the paper further.

    1. Reviewer #3 (Public Review):

      Neuronal migration is one of the key processes for appropriate neuronal development. Defects in neuronal migration are associated with different brain disorders often accompanied by intellectual disabilities. Therefore, the study of the mechanisms involved in neuronal migration helps to understand the pathogenesis of some brain malformations and psychiatric disorders.

      FMRP is an RNA-binding protein implicated in RNA metabolism regulation and mRNA local translation. FMRP loss of function causes fragile X syndrome (FXS), the most common form of inherited intellectual disability. Previous studies have shown the role of FMRP in the multipolar to bipolar transition during the radial migration in the cortex and its possible relation with periventricular heterotopia and altered synaptic communication in humans with FXS. However, the role of FMRP in neuronal tangential migration is largely unknown. In this manuscript, the authors aim to decipher the role of FMRP in the tangential migration of neuroblasts along the rostral migratory stream (RMS) in the postnatal brain. By extensive live-imaging analysis of migrating neuroblasts along the RMS, they demonstrate the requirement of FMRP for neuroblast migration and centrosomal movement. These migratory defects are cell-autonomous and mediated by the microtubule-associated protein Map1b.

      Overall, the manuscript highlights the importance of FMRP in neuronal tangential migration. They performed an analysis of different aspects of migration such as nucleokinesis and cytokinesis in migrating neuroblasts from live-imaging videos.<br /> However, the work is quite incomplete. The role of FMRP and Map1b in neuronal migration is not well introduced and discussed. In the cortex, FMRP is mainly implicated in the multipolar to bipolar transition of immature neurons, but not in the migration itself (la Fata et al., 2014). In fact, Fmr1 KO mice do not show impairment in cortical lamination. On the other hand, very less is mentioned about the role of Map1b in neuronal migration. It is not shown whether overexpression of Map1b alters neuroblast migration and recapitulates the Fmr1 KO phenotype.

      Moreover, it is unclear to me which are the anatomical consequences of aberrant migration of neuroblasts in the Fmr1 KO mice. Authors mention that neuroblasts properly arrive at the OB and they refer to a previous publication (Scotto-Lomassese et al., 2011). However, this study does not show the distribution of neuroblasts in the SVZ, along the RMS or in the olfactory bulb (OB) in mutant mice. On the contrary, they said that there is no delay in the migration or maturation of granular cells arriving at the OB (Scotto-Lomassese et al., 2011). In summary, the authors do not show the functional consequences of aberrant neuroblast migration in the Fmr1 KO mice, making weaker the assumption that the study is important for the understanding of FXS pathophysiology.

    1. Reviewer #3 (Public Review):

      This important manuscript investigates the role of basal forebrain cholinergic interneurons in conditioned responding by measuring the licking behaviour of head-fixed mice during photostimulation of the aforementioned neurons. Licking is found to increase only during windows when licking is rewarded, and similar behaviour is observed when terminals are stimulated in basolateral amygdala, then several more experiments are conducted to determine the behavioural and anatomical specificity of the effect. The findings are solid, particularly those relating to the recordings, although the interpretation of the behavioural findings is still somewhat unclear.

      Strengths<br /> • The manuscript is beautifully written and structured. I found it really easy to follow and felt that the authors did an exceptional job of walking me through each experiment that they completed, the rationale for it, and what they found.<br /> • The question of the function of basal forebrain cholinergics is an interesting one and a somewhat understudied question, so the study is timely and on an interesting topic.<br /> • The experiments are well-designed and the findings are novel. There are a number of important control experiments performed to determine that the observed effects were not due to locomotor activity and that stimulating basal forebrain ACh neurons is not inherently reinforcing.<br /> • The discussion is really nice - covering important topics such as potential interactions with dopamine, the potential anatomical specificity of the effects observed, and the possibility that projections other than those studied here might mediate effects, among other things.

      Weaknesses<br /> • Although very clearly written and set out, I found myself confused by the behavioural findings and their interpretation. Mainly this was because photostimulation only increased licking during the window of opportunity, which is not signalled by any discrete stimulus, which means that the only signal that the animal receives to determine that they are within the reward window is them receiving the reward. Therefore, the only time within this window that licking could be increased is post-reward (otherwise the reward window is identical to a non-rewarded window) and it is not clear to me what this increase in post-award licking might mean? In fact, this time post-award is actually the time the animal is most certain to not receive another reward for a few seconds, meaning that licking at this time is not a useful behaviour and therefore it is difficult to interpret what it means to artificially increase licking at this time. I think it would probably have been less confusing for the authors to study a paradigm in which animals develop a conditioned response that is unsignaled by discrete stimuli and then to inhibit basal forebrain ACh prior to that response.<br /> • I should also note that the authors state (Lines 249-251) that stimulation increases responding prior to reinforcer delivery, but I couldn't find evidence for this, and it seems counterintuitive to me that it would do so because then how would the animals discriminate the window of opportunity from a non-rewarded window? Perhaps I misunderstood something, but I found this confusing.<br /> • I do not think the behaviour in this task can be classed as operant - it is still a good task and still fine for detecting conditioned responding, but it cannot determine whether the responding is governed by a response-outcome association in the absence of a stimulus-outcome association (with stimuli being the licking spout, other facets of the behavioural context etc) through bidirectionality or omission, as would be required to demonstrate its operant nature.<br /> • I was confused by the pupil dilation data in Figure S4 as the authors seem to want to argue that this effect, although specific to the rewarded window as licking is, is independent of the licking behaviour as it develops more slowly than the behaviour (Lines 201-202). I was curious as to how the authors interpret these data then? Does it indicate that stimulating basal forebrain ACh interneurons does both things (i.e. increases arousal AND conditioned responding in the absence of discrete stimuli) but that the two things are independent of each other?<br /> • The authors refer to the dorsal medial prefrontal cortex in mice, which from the methods appears to be the prelimbic region. My understanding is that dmPFC has fallen out of favour for use in mice as it is not homologous to the same region in primates and can be confusing for this reason.

    1. Reviewer #3 (Public Review):

      Summary:<br /> The present article attempts to answer both the ultimate question of why different stinging behaviours have evolved in Cnidiarians with different ecological niches and shed light on the proximate question of which electro-physiological mechanisms underlie these distinct behaviours.

      Account of major methods and results:<br /> In the first part of the paper, the authors try to answer the ultimate question of why distinct dependencies of the sting response on internal starvation levels have evolved. The premise of the article that Exaiptasia's nematocyte discharge is independent of the presence of prey (Artemia nauplii) as compared to Nematostella's significant dependence of the discharge on the presence of actual prey, is shown be a robust phenomenon justified by the data in Figure 1.

      The hypothesis that defensive vs. predatory stinging leads to different nematocyte discharge behaviours is analysed in mathematical models based on the suitable framework of optimal control/decision theory. By assuming functional relations between the:<br /> 1) cost of a full nematocyte discharge and the starvation level.<br /> 2) probability of successful predation/avoidance on the discharge level.<br /> 3) desirability/reward of the reached nutritional state.

      Based on these assumptions of environmental and internal influences, the optimal choice of attack intensity is calculated using Bellman's equation for this problem. The model predictions are validated using counted nematocytes on a coverslip. The scaling of normalised nematocyte discharge numbers with scaled starvation time is qualitatively comparable to what is predicted from the models. The abundance of nematocytes in the tentacles was, on the other hand, independent of the starvation state of the animals.

      Next, the authors turn to investigate the proximate cause of the differential stinging behaviour. The authors have previously reported convincing evidence that a strongly inactivating Cav2.1 channel ortholog (nCav) is used by Nematostella to prevent stinging in the absence of prey (Weir et al. 2020). This inactivation is released by hyperpolarising sensory inputs signalling the presence of prey. In this article, it is clearly shown by blocking respective currents that Exaiptasia, too, relies on extracellular Ca2+ influx to initiate stinging. Patch clamp data of the involved currents is provided in support. However, the authors find that in addition to the nCav with a low-inactivation threshold, Exaiptasia has a splice variant with a higher inactivation threshold expressed (Figure 3D).

      The authors hypothesise that it is this high-threshold nCav channel population that amplifies any voltage depolarisation to release a sting irrespective of the presence of prey signals. They found that the β subunit that is responsible for Nematostella's unusually low inactivation threshold exists in Exaiptasia as two alternative splice isoforms. These N-terminus variants also showed the greatest variation in a phylogenetic comparison (Figure 5), rendering it a candidate target for mutations causing variation in stinging responses.

      Appraisal of methodology in support of the conclusions:<br /> The authors base their inference on a normative model that yields quantitative predictions which is an exciting and challenging approach. The authors take care in stating the model assumptions as well as showing that the data indeed does not contradict their model predictions. The interesting comparative nature of the modelling part of the study is complicated by slightly different cost assumptions for the two scenarios. Hence, Figure 2 needs to be carefully digested by readers.

      It would be even more prudent to analyse the same set of cost-of-discharge vs. starvation scenarios for both species. Specifically, for Nematostella the complete cost-of-discharge vs starvation-state curves as for Exaiptasia (Figure 2E, example 2-4) could be used. It is likely that the differential effect size of Nematostella and Exaiptasia behaviour is the strongest if only the flat cost-of-discharge vs starvation is used (Figure 2A) for Nematostella. But as a worst-case comparison the other curves, where the cost to the animal scales with starvation would be a good comparison. This could help the reader to understand when the different prediction of Nematostella's behaviour breaks down. In addition, this minor change could shed light on broader topics like common trade-offs in pursuit predation.

      The qualitatively similar scaling of the model-derived relation between starvation and sting intensity with the counted nematocytes for different feeding pauses is evidence that feeding has indeed been optimised for the two distinct ecological niches.<br /> To prove that Exaiptasia uses a similar Ca2+ channel ortholog as well as a different splice variant, the authors employed both clean electrophysiological characterisaiton (Figure 3) as well as transcriptomics data (Figure 4S1).

      To strengthen the authors' hypothesis that variation in the N-termini leads to changes in Ca2+ channel inactivation and hence altered stinging, the response sequence variability of 6 Cnidaria was analysed.

      Additional context:<br /> Although, the present article focuses on nematocytes alone, currently, there has been a refocus in neurobiology on the nervous systems of more basal metazoans, which received much attention already in the works of Romanes (1885). In part, this is driven by the goal to understand the early evolution of nervous systems. Cnidarians and Ctenophors are exciting model organisms in this venture. This will hopefully be accompanied by more comparative studies like the present one. Some of the recent literature also uses computational models to understand mechanisms of motor behaviour using full-body simulations (Pallasdies et al. 2019; Wang et al. 2023), which can be thought of as complementary to the normative modelling provided by the authors.

      Comparative studies of recent Cnidarians, such as the present article, can shed light on speculative ideas on the origin of nervous systems (Jékely, Keijzer, and Godfrey-Smith 2015). During a time (the Ediacarium/Cambrium transition) that has seen the genesis of complex trophic foodwebs with preditor-prey interaction, symbioses, but also an increase of body sizes and shapes, multiple ultimate causes can be envisioned that drove the increase in behavioural complexity. The authors show that not all of it needs to be implemented in dedicated nerve cells.

      References:

      Jékely, Gáspár, Fred Keijzer, and Peter Godfrey-Smith. 2015. "An Option Space for Early Neural Evolution." Philosophical Transactions of the Royal Society B: Biological Sciences 370 (December): 20150181. https://doi.org/10.1098/rstb.2015.0181.

      Pallasdies, Fabian, Sven Goedeke, Wilhelm Braun, and Raoul-Martin Memmesheimer. 2019. "From Single Neurons to Behavior in the Jellyfish Aurelia Aurita." eLife 8 (December). https://doi.org/10.7554/elife.50084.

      Romanes, G. J. 1885. Jelly-Fish, Star-Fish and Sea-Urchins: Being a Research on Primitive Nervous Systems. Appleton.

      Wang, Hengji, Joshua Swore, Shashank Sharma, John R. Szymanski, Rafael Yuste, Thomas L. Daniel, Michael Regnier, Martha M. Bosma, and Adrienne L. Fairhall. 2023. "A Complete Biomechanical Model of hydra Contractile Behaviors, from Neural Drive to Muscle to Movement." Proceedings of the National Academy of Sciences 120 (March). https://doi.org/10.1073/pnas.2210439120.

      Weir, Keiko, Christophe Dupre, Lena van Giesen, Amy S-Y Lee, and Nicholas W Bellono. 2020. "A Molecular Filter for the Cnidarian Stinging Response." eLife 9 (May). https://doi.org/10.7554/elife.57578.

    1. Reviewer #3 (Public Review):

      In this study, Hwangbo and co-workers investigate the extent to which the well-established life extending effects of DR rely on the molecular circadian clock and how the landscape of clock-controlled gene expression changes in the face of DR within the fat body of the fly, a tissue that performs the functions associate with both the liver and adipose tissue of mammals. The authors evidence that DR extends lifespan in a manner that depends on only one of the two major limbs of the fly's molecular circadian clock, namely the positive limb, that DR produces major changes in the identities of cycling clock output genes, and that genes related to the proteosome represent a major component of DR-induced transcript cycling. Though interesting, these conclusions are not strongly supported by the data and there are two major reasons for this. First, the authors rely on only one loss of function genotype each for the loss of positive and negative limb clock gene function. Second, though they wish to address the "circadian transcriptome" under normal and DR conditions, the authors conduct all their work under strong Light/Dark cycles, making it impossible to address circadian phenomena. These shortcomings are problematic in the extreme, as they leave open obvious alternative explanations for the results and fail to directly determine if the rhythmic expression, they observe are clock controlled or merely driven by the light/dark cycles, which themselves produce major effects on activity, feeding, etc., that may be responsible for differentially driving rhythmic transcripts under normal and DR conditions in the fat bodies.

      Major Weakness One: The use of only genotype each for the loss of positive (Clk^JRK) and negative (Per^01) limb of the circadian represents a major challenge for a central conclusion of the study. Phenotypes caused by the loss of a single clock gene may be due to the loss of circadian timekeeping, or they may represent a pleiotropic effect of the loss of function mutant being used. There are multiple precedents for pleiotropic (non-circadian) effects of clock gene mutants. It is, therefore, possible that the differences in the extent of DR mediated life extension between Clk^JRK and Per^01 may not represent a difference between breaking the positive and negative limbs of the clock but may simply reflect a pleiotropic effect of the dominant negative Clk^JRK. This possibility is acknowledged by the authors (lines 343-344). This could be addressed quite easily by extending the analysis to other loss of function mutants, for example, tim01 for the negative limb and cyc01 for the positive. Given the central focus here on the "circadian transcriptome," leaving open this alternative explanation for Clk's role in DR induced life extension represents a major weakness of the study. Furthermore, given the fact that Clk^JRK appears to be short lived on most of the media tested in the study, is it really surprising or informative that they would display lower life extension under DR?

      Major Weakness Two: The authors have not established that any of cycling transcripts they have detected in the fat body under normal and DR conditions are driven by the circadian clock. This is because: 1.) they have conducted their transcriptomic analysis on cells taken from flies entrained to light dark cycles, which can themselves drive daily changes in expression levels and 2.) they have not shown that the cycling measured on normal diet or DR conditions depends on a functional circadian clock. The "significant reorganization of the circadian transcriptome" is presented as a major conclusion of this study, but the authors have not addressed circadian control of transcription at all here, either by an examination of transcription under free-running conditions and/or in loss of function clock mutants.

      In addition, there is a logical gap in this study. The authors have shown that DR produces less life extension in Clk^JRK mutants than Per^01 or wild-type controls. They then show that DR produces changes in the rhythmic transcriptome when flies are place on DR. The central model presented in Fig. 6 shows/concludes that CLK drives increases in proteome-related transcript rhythms under DR. This conclusion could have been directly tested by asking if the changes in rhythmic gene expression induced by DR are gone the loss of function Clk mutants, or if the transcriptomic landscapes fail to differ between feeding conditions in these mutants.

      In conclusion, the study falls far short of directly testing the ideas it puts forth, greatly limiting its impact and interest.

    1. Reviewer #3 (Public Review):

      In this study, Ciampa and colleagues demonstrate that HIF-1α activity is increased with gestation in humans and mice placentas and use several in vitro models to indicate that HIF activation in trophoblasts may release factors (yet to be identified) which promote myometrial contraction. Previous studies have linked placental factors to the preparation of the myometrium for labour (e.g. prostaglandins), but HIF-1α has not been implicated.

      Weaknesses and concerns:

      1) The author's rebuttal state that placentas undergo subclinical cellular aging as they reach term. Although several future studies are described to test functional deficits at the cellular level, the current manuscript does not provide convincing evidence of cellular aging. The only evidence of cellular senescence provided in both human and mouse data is the mRNA expression of a single gene associated with senescence.

      2) The authors have not responded to the concern regarding CoCl2 mediating differentiation. The paragraph from a ref states that JAR cells do not respond as well as BeWOs to forskolin. However, this does not mean that JAR cells do not differentiate. This point is particularly pertinent as a quick search of their RNA-seq data shows upregulation of STB genes following CoCl2 treatment including ERVs (ERVFRD1, ERVV-1, ERVV-2, ERV3-1), CYP19A1 and OVOL1 just to name a few. If the authors' conclusion is that CoCl2 treatment did not alter trophoblast differentiation, the authors should provide additional data showing this. For example, cell fusion assays showing E-cadherin/desmoplakin staining and nuclear localization within stained boundaries.

      3) The authors acknowledge the possibility of extraplacental effects of DMOG in the initiation of labour in their model, no additional evidence has been provided to support placental effects of their model. The authors also argue that although PMID 30808919 (which specifically overexpressed HIF-1a in the placenta) did not show changes in birth length, they propose that this may be due to constitutive HIF1a expression at the beginning of pregnancy. This argument is invalid since placental maldevelopment is consistently linked with several pregnancy complications including spontaneous preterm birth. If anything, perturbations in the beginning of pregnancy are more likely to lead to worse outcomes than those at the end of pregnancy.

      4) Regarding induction of syncytialisation, please provide additional evidence that the cells have/have not syncytialised.

      5) Lack of cohesion between experimental models. Please provide evidence that DMOG mediates similar effects on SA-β gal activity as CoCl2 in JARs.

      6) Evidence of senescence and mitochondrial abundance could be strengthened by providing additional markers. E.g. only GLB1 mRNA expression is provided as evidence of senescence, and COX IV protein for mitochondrial abundance in mouse and human placentas. This point has not been addressed. Please provide at least one additional marker of senescence and mitochondrial abundance.

    1. Reviewer #3 (Public Review):

      The computational study reported in the manuscript "Free energy landscapes of KcsA inactivation" by Pérez-Conesa and Delemotte is quite interesting and insightful.

      The computations provide the first complete analysis of how the opening of the activation gate and the constriction of the selectivity filter are coupled in the KcsA channel.

      The analysis is careful and is state-of-the-art. The results reveal remarkable differences between the CHARMM and AMBER force fields.

      Unfortunately, the "elephant in the room" with regards to K+ channel inactivation is the significance of the dilated structures more recently obtained by Xray and EM. While it is worthwhile doing our best to really understand the constriction mechanism of KcsA, and the present manuscript does an excellent job at that, the ground has shifted and understanding finer points about KcsA constriction has become, unfortunately, not the most prominent issue in the field at the present time.

      Let's discuss the current situation about the inactivation of K+ channels. The situation is fairly unsettled. The KcsA channel was the first for which some atomic structure and mechanism, centered on a constriction of the selectivity filter, were proposed. The constricted conformation really does not conduct because the filter is too narrow. More recently a few structures (Xray and EM) for channel mutants known to have more propensity to inactivate have revealed a different conformation of the filter which appears to be dilated toward the extracellular side. This is a conformation that had never been seen previously. Different "camps" co-exist in the K+ channel community about inactivation. Those who were very skeptical about the constricted conformation claim that the new dilated structures is the final truth. While the dilated structures are certainly part of the body of information that we have now, but their significance remains somewhat unclear if anything because of the fact that they are not perfectly occluded and they allow ion conduction! While it is worthwhile doing our best to really understand the constriction mechanism of KcsA, and the present manuscript does an excellent job at that, the ground has shifted and understanding finer points about KcsA constriction has become, unfortunately, not the most prominent issue in the field at the present time.

    1. Reviewer #3 (Public Review):

      How chromatin state is defined is an important question in the epigenetics field. Here, Jamge et al. proposed that the dynamics of histone variant exchange control the organization of histone modifications into chromatin states. They found 1) there is a tight association between H2A variants and histone modifications; 2) H2A variants are major factors that differentiate euchromatin, facultative heterochromatin, and constitutive heterochromatin; 3) the mutation in DDM1, a remodeler of H2A variants, causes the mis-assembly of chromatin states in TE region. The topic of this paper is of general interest and the results are novel.

      Overall, the paper is well-written and the results are clearly presented. The biochemical analysis part is solid.

    1. Reviewer #3 (Public Review):

      In this work, Urbanska et al. link the mechanical phenotypes of human glioblastoma cell lines and murine iPSCs to their transcriptome, and using machine learning-based network analysis identify genes with putative roles in cell mechanics regulation. The authors identify 5 target genes whose transcription creates a combinatorial marker which can predict cell stiffness in human carcinoma and breast epithelium cell lines as well as in developing mouse neurons. For one of the target genes, caveolin1 (CAV1), the authors perform knockout, knockdown, overexpression and rescue experiments in human carcinoma and breast epithelium cell lines. They determine the cell stiffness via RT-DC, AFM indentation and AFM rheology and confirm that high CAV1 expression levels correlate with increased stiffness in those model systems. This work brings forward an interesting approach to identify novel genes in an unbiased manner, but surprisingly the authors validate caveolin 1, a target gene with known roles in cell mechanics regulation.

      I have two main concerns with the current version of this work:<br /> 1) The authors identify a network of 5 genes that can predict mechanics. What is the relationship between the 5 genes? If the authors aim to highlight the power of their approach by knockdown, knockout or over-expression of a single gene why choose CAV1 (which has an individual p-value of 0.16 in Fig S4)? To justify their choice, the authors claim that there is limited data supporting the direct impact of CAV1 on mechanical properties of cells but several studies have previously shown its role in for example zebrafish heart stiffness, where a knockout leads to higher stiffness (Grivas et al., Scientific Reports 2020), in cancer cells, where a knockdown leads to cell softening (Lin et al., Oncotarget 2015), or in endothelial cell, where a knockout leads to cell softening (Le Master et al., Scientific Reports 2022).<br /> 2) The authors do not show how much does PC-Corr outperforms classical co-expression network analysis or an alternative gold standard. It is worth noting that PC-Corr was previously published by the same authors to infer phenotype-associated functional network modules from omics datasets (Ciucci et al., Scientific Reports 2017).

      Altogether, the authors provide an interesting approach to identify novel genes associated with cell mechanics changes, but the current version does not fulfill such potential by focusing on a single gene with known roles in cell mechanics.

    1. Reviewer #3 (Public Review):

      The goal of this study was to use a combination of fluorescent dyes and genetically encoded reporters to estimate the temperature of mitochondria. The authors provide additional evidence that they claim to support "hot" mitochondria.

      Strengths:<br /> 1. The authors use several methods, including a mitochondrial fluorescent reporter dye, as well as a genetically encoded gTEMP temperature probe, to estimate mitochondrial temperature.<br /> 2. The authors couple these measurements with other perturbation of mitochondria, such as OXPHOS inhibitors, to show consistency

      Weaknesses:<br /> 1. The methodology for inferring mitochondrial temperature is not well-established to begin with and requires additional controls for interpretation.<br /> a. Very little benchmarking is done of the "basal" fluorescence ratio, and whether that fluorescence ratio actually reflects true organelle temperature. For instance, the authors should in parallel compare between different organelles to see if only mitochondria appear "hot" or whether this is some calibration error. Another control is to use different incubator temperatures and see how mitochondrial (vs other organelle) temperature varies as a function of external temperature.<br /> b. The authors do not rigorously control for other factors that may also be changing fluorescence and may be confounders to the delta fluorescence (eg, delta calcium in response to mito inhibitors, membrane potential, redox status, ROS, etc.). There should be additional calibration for all potential confounders.<br /> c. It was unclear where the mito-targeted dyes/probes localized in terms of mitochondrial compartment. Regardless, one important control would be to target these dyes to each of the different compartments eg. Matrix vs IMS vs outer membrane to determine if a gradient of temperatures can be observed.<br /> d. Can these probes be used in isolated mitochondria and other isolated organelles. Such data would also help to clarify whether the high temperature is a specific to mitochondria.<br /> 2. The authors should try to calibrate their fluorescence inference of temperature with an alternative method and benchmark to others in the field. For instance, Okabe et al Nat Comm 2012 used a polymeric thermometer to measure temperature and reported 33degC cytoplasm and 35degC nucleus. Can the authors also show a ~2degC difference in their hands between those two compartments, and under those conditions are mitochondria still 10degC hotter?<br /> 3. There are some theoretical considerations and critiques about temperature imaging in cells (eg Baffou et al Nat Methods 2014; Lane et al Plos Biology 2018), and the possible magnitude of theoretical variation between compartments. The authors should address some of those theoretical concerns, either experimentally or in the discussion.

      Based on the aforementioned weaknesses, in my opinion, the authors did not achieve their Aims to accurately determine the temperature of mitochondria. The results, while interesting, are preliminary and require additional controls before conclusions can be drawn. Previous studies have indicated intra-organelle temperature variations within cells; typically, previous reports have estimated that the variation is within a few degrees (Okabe et al Nat Comm 2012). Only one report has previously suggested that mitochondria are at 50degC (Cretien, Plos biology 2018). The study does not substantially clarify the true temperature of mitochondria or resolve potential discrepancies in previous estimates of mitochondrial temperature.

    1. Reviewer #3 (Public Review):

      To assess the degree to which highly social primates like marmosets share a human-like Theory of Mind (ToM), the authors used eye tracking and functional magnetic resonance brain imaging on marmosets and humans who were viewing two of the three categories from classic Frith-Happé animations. Humans viewing the ToM animations showed, relative to the random movement animations, longer fixation times, more viewing of the large shape, and more viewing of the small shape. In contrast, the marmosets did not differ in their viewing of the ToM videos as a category and did not show differential viewing of the small shape. The marmosets did show differential viewing of the large shape, but this difference was blunted relative to that seen in humans. Neurally, both species showed widespread brain activation in many areas that discriminated between ToM videos and random movement videos. This pattern of activation partially overlapped and partially was different in humans and marmosets. It was also partially overlapping and partially different when comparing humans in this study to humans in another study. Overall, the authors conclude that their evidence cannot address whether marmosets have a Theory of Mind, but that marmosets show a "clear preference for interacting shapes" that may be an ancestral form of human Theory of Mind.

      There are several laudable strengths to this report. It reports a direct human/monkey comparison. It uses a robust population of subjects, especially for the monkey experiment. It uses strong imaging methods that use modern parcellation maps, compares human data from this study to comparable data from another study, and accounts for lateralization differences convincingly using maps of signal-to-noise ratio. It uses eye-tracking methods and stimuli that are solidly grounded in the human literature and that has recently been used in a different monkey species.

      Unfortunately, the weaknesses of this report limit its interpretability. First, it omits one of the three major categories of the Frith-Happé animations: Goal-Directed actions. Data from this category are critical because they provide a case where the shapes are engaging in biological motion but are not behaving as if they attribute minds to each other. Without including it, readers cannot interpret whether any given finding is due to biological motion or mentalizing. Second, the study did not gather explicit reports of mental state attribution from humans. This does not allow for a manipulation check about whether humans were even engaging in mentalizing and does not allow the researchers to separate out what brain activation patterns are due to mentalizing and which are due to eye movements or stimulus movement. Third, in interpreting the data, the researchers gloss over the major species differences and primarily focus on one small species similarity. Both this study and a previous human study (Klein et al., 2009, Quart. J. Exp. Psychol.) have shown longer fixations for the ToM videos relative to the random motion videos and that these fixations correlate with explicit ratings of the intentionality of the shapes (Klein et al., 2009). That the marmosets don't show this difference should be a major piece of evidence against the hypothesis that they are engaging in anything like mentalizing. The marmosets also failed to show a viewing difference for the small shape. In short, the small viewing difference in the large shape, itself blunted relative to that seen in humans, is not sufficient evidence to justify the conclusion that marmosets engage in anything like ToM or even that they show a "clear preference for interacting shapes". Fourth, alternative explanations for the small differences that do exist were not sufficiently explored. The videos that make up the categories in the Frith-Happé animations differ in many ways, such as in the amount of visual motion, smoothness/jerkiness of motion, amount of the screen taken up by shapes vs white space, etc. Indeed, in the prior study to use these stimuli with monkeys, the authors also found that the categories differed in viewing parameters but that this difference disappeared once low-level visual motion was accounted for (Schafroth et al., 2021, Sci. Rep.). Without a similar analysis here or a second experiment that assesses generalization to stimuli that don't differ on low-level perceptual features, readers cannot know whether the small viewing difference that exists is due to something like mentalizing or something about low-level visual motion. Indeed, other studies have found overlapping brain activity patterns in monkeys that are driven primarily by low-level visual motion (e.g., Russ et al., 2015, Neuroimage). Fifth, the prior monkey study to use these stimuli raised the point that these stimuli may not even be appropriate to test ToM in nonhumans. Human-like displays of "mocking", "coaxing", or "seducing" are likely meaningless to monkeys. This weakness has not been addressed in the current study.

      Considering the weaknesses in the behavioral methods, the well-collected neural activity patterns cannot be interpreted in a meaningful way. As such, the authors' conclusions are not justified at the current time. Nevertheless, this report may be useful to others who attempt similar experiments of their own.