Transport of DNA within cohesin involves clamping on top of engaged heads by Scc2 and entrapment within the ring by Scc3
In addition to extruding DNA loops, cohesin entraps within its SMC-kleisin ring (S-K) individual DNAs during G1 and sister DNAs during S-phase. All three activities require related hook-shaped proteins called Scc2 and Scc3. Using thiol-specific crosslinking we provide rigorous proof of entrapment activity in vitro. Scc2 alone promotes entrapment of DNAs in the E-S and E-K compartments, between ATP-bound engaged heads and the SMC hinge and associated kleisin, respectively. This does not require ATP hydrolysis nor is it accompanied by entrapment within S-K rings, which is a slower process requiring Scc3. Cryo-EM reveals that...
Source: eLife - September 15, 2020 Category: Biomedical Science Tags: Biochemistry and Chemical Biology Source Type: research

Meta Research: Questionable research practices may have little effect on replicability
This article examines why many studies fail to replicate statistically significant published results. We address this issue within a general statistical framework that also allows us to include various questionable research practices (QRPs) that are thought to reduce replicability. The analyses indicate that the base rate of true effects is the major factor that determines the replication rate of scientific results. Specifically, for purely statistical reasons, replicability is low in research domains where true effects are rare (e.g., search for effective drugs in pharmacology). This point is under-appreciated in current ...
Source: eLife - September 15, 2020 Category: Biomedical Science Source Type: research

TMEM79/MATTRIN defines a pathway for Frizzled regulation and is required for Xenopus embryogenesis
Wnt signaling through the Frizzled (FZD) family of serpentine receptors is essential for embryogenesis and homeostasis, and stringent control of the FZD protein level is critical for stem cell regulation. Through CRISPR/Cas9 genome-wide screening in human cells, we identified TMEM79/MATTRIN, an orphan multi-span transmembrane protein, as a specific inhibitor of Wnt/FZD signaling. TMEM79 interacts with FZD during biogenesis and promotes FZD degradation independent of ZNRF3/RNF43 ubiquitin ligases (R-spondin receptors). TMEM79 interacts withubiquitin-specificprotease 8 (USP8), whose activating mutations underlie human tumori...
Source: eLife - September 14, 2020 Category: Biomedical Science Tags: Cell Biology Developmental Biology Source Type: research

Meta-Research: Evaluating the impact of open access policies on research institutions
The proportion of research outputs published in open access journals or made available on other freely-accessible platforms has increased over the past two decades, driven largely by funder mandates, institutional policies, grass-roots advocacy, and changing attitudes in the research community. However, the relative effectiveness of these different interventions has remained largely unexplored. Here we present a robust, transparent and updateable method for analysing how these interventions affect the open access performance of individual institutes. We studied 1,207 institutions from across the world, and found that, in 2...
Source: eLife - September 14, 2020 Category: Biomedical Science Source Type: research

A large accessory protein interactome is rewired across environments
To characterize how protein-protein interaction (PPI) networks change, we quantified the relative PPI abundance of 1.6 million protein pairs in the yeastSaccharomyces cerevisiae across 9 growth conditions, with replication, for a total of 44 million measurements. Our multi-condition screen identified 13,764 pairwise PPIs, a 3-fold increase over PPIs identified in one condition. A few 'immutable' PPIs are present across all conditions, while most 'mutable' PPIs are rarely observed. Immutable PPIs aggregate into highly connected 'core' network modules, with most network remodeling occurring within a loosely connected 'access...
Source: eLife - September 14, 2020 Category: Biomedical Science Tags: Computational and Systems Biology Source Type: research

The many roles of C1q
The ability of a well-known component of the complement cascade to bind to a variety of receptors has implications for signaling biology, spinal cord injury and, possibly, the evolution of the complement system. (Source: eLife)
Source: eLife - September 14, 2020 Category: Biomedical Science Tags: Stem Cells and Regenerative Medicine Source Type: research

Structure of the bacterial ribosome at 2 Å resolution
Using cryo-electron microscopy (cryo-EM), we determined the structure of theEscherichia coli70S ribosome with a global resolution of 2.0 A ̊. The maps reveal unambiguous positioning of protein and RNA residues, their detailed chemical interactions, and chemical modifications. Notable features include the first examples of isopeptide and thioamide backbone substitutions in ribosomal proteins, the former likely conserved in all domains of life. The maps also reveal extensive solvation of the small (30S) ribosomal subunit, and interactions with A-site and P-site tRNAs, mRNA, and the antibiotic paromomycin. The maps and model...
Source: eLife - September 14, 2020 Category: Biomedical Science Tags: Structural Biology and Molecular Biophysics Source Type: research

Vascular control of the CO < sub > 2 < /sub > /H < sup > + < /sup > dependent drive to breathe
Respiratory chemoreceptors regulate breathing in response to changes in tissue CO2/H+. Blood flow is a fundamental determinant of tissue CO2/H+, yet little is known regarding how regulation of vascular tone in chemoreceptor regions contributes to respiratory behavior. Previously, we showed in rat that CO2/H+-vasoconstriction in the retrotrapezoid nucleus (RTN) supports chemoreception by a purinergic-dependent mechanism (Hawkins et al. 2017). Here, we show in mice that CO2/H+ dilates arterioles in other chemoreceptor regions, thus demonstrating CO2/H+ vascular reactivity in the RTN is unique. We also identify P2Y2 receptors...
Source: eLife - September 14, 2020 Category: Biomedical Science Tags: Neuroscience Source Type: research

When pH comes to the rescue
In starving yeast exposed to thermal stress, a transient drop in intracellular pH helps to trigger the heat shock response. (Source: eLife)
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Biochemistry and Chemical Biology Cell Biology Source Type: research

Large domains of heterochromatin direct the formation of short mitotic chromosome loops
During mitosis chromosomes reorganise into highly compact, rod-shaped forms, thought to consist of consecutive chromatin loops around a central protein scaffold. Condensin complexes are involved in chromatin compaction, but the contribution of other chromatin proteins, DNA sequence and histone modifications is less understood. A large region of fission yeast DNA inserted into a mouse chromosome was previously observed to adopt a mitotic organisation distinct from that of surrounding mouse DNA. Here we show that a similar distinct structure is common to a large subset of insertion events in both mouse and human cells and is...
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Cell Biology Chromosomes and Gene Expression Source Type: research

Alternative splicing at neuroligin site A regulates glycan interaction and synaptogenic activity
Post-transcriptional mechanisms regulating cell surface synaptic organizing complexes that control the properties of connections in brain circuits are poorly understood. Alternative splicing regulates the prototypical synaptic organizing complex, neuroligin-neurexin. In contrast to the well-studied neuroligin splice site B, little is known about splice site A. We discovered that inclusion of the positively charged A1 insert in mouse neuroligin-1 increases its binding to heparan sulphate, a modification on neurexin. The A1 insert increases neurexin recruitment, presynaptic differentiation, and synaptic transmission mediated...
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Developmental Biology Neuroscience Source Type: research

Stress-activated MAPK signalling controls fission yeast actomyosin ring integrity by modulating formin For3 levels
Cytokinesis, which enables the physical separation of daughter cells once mitosis has been completed, is executed in fungal and animal cells by a contractile actin- and myosin-based ring (CAR). In the fission yeastSchizosaccharomyces pombethe formin For3 nucleates actin cables and also co-operates for CAR assembly during cytokinesis. Mitogen-Activated Protein Kinases (MAPKs) regulate essential adaptive responses in eukaryotic organisms to environmental changes. We show that the Stress Activated Protein Kinase pathway (SAPK) and its effector, MAPK Sty1, downregulates CAR assembly inS. pombe when its integrity becomes compro...
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Cell Biology Microbiology and Infectious Disease Source Type: research

Neural variability determines coding strategies for natural self-motion in macaque monkeys
We have previously reported that central neurons mediating vestibulo-spinal reflexes and self-motion perception optimally encode natural self-motion (Mitchell et al., 2018). Importantly however, the vestibular nuclei also comprise other neuronal classes that mediate essential functions such as the vestibulo-ocular reflex (VOR) and its adaptation. Here we show that heterogeneities in resting discharge variability mediate a trade-off between faithful encoding and optimal coding via temporal whitening. Specifically, neurons displaying lower variability did not whiten naturalistic self-motion but instead faithfully represented...
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Neuroscience Source Type: research

Structural Insights into Human Acid-sensing Ion Channel 1a Inhibition by Snake Toxin Mambalgin1
Acid-sensing ion channels (ASICs) are proton-gated cation channels that are involved in diverse neuronal processes including pain sensing. Peptide toxin Mambalgin1 (Mamba1) from black mamba snake venom can reversibly inhibit the conductance of ASICs, showing an analgesic effect. However, the detailed inhibitory mechanism of Mamba1 on ASIC1s, especially how Mamba1 binding to extracellular domain affects the conformational changes of the transmembrane domain of ASICs remains elusive. Here, we present single-particle cryo-EM structures of human ASIC1a (hASIC1a) and hASIC1a-Mamba1 complex at resolutions of 3.56 and 3.90 Å...
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Structural Biology and Molecular Biophysics Source Type: research

More than just a pool
An intricate stem cell niche boundary formed by finger-like extensions generates asymmetry in stem cell divisions. (Source: eLife)
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Developmental Biology Source Type: research

Structural basis of αE-catenin-F-actin catch bond behavior
Cell-cell and cell-matrix junctions transmit mechanical forces during tissue morphogenesis and homeostasis. α-Catenin links cell-cell adhesion complexes to the actin cytoskeleton, and mechanical load strengthens its binding to F-actin in a direction-sensitive manner. Specifically, optical trap experiments revealed that force promotes a transition between weak and strong actin-bound states. Here, we descr ibe the cryo-electron microscopy structure of the F-actin-bound αE-catenin actin-binding domain, which in solution forms a 5-helix bundle. In the actin-bound structure, the first helix of the bundle dissociates...
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Structural Biology and Molecular Biophysics Source Type: research

A single-cell atlas of the mouse and human prostate reveals heterogeneity and conservation of epithelial progenitors
Understanding the cellular constituents of the prostate is essential for identifying the cell of origin for prostate adenocarcinoma. Here we describe a comprehensive single-cell atlas of the adult mouse prostate epithelium, which displays extensive heterogeneity. We observe distal lobe-specific luminal epithelial populations (LumA, LumD, LumL, and LumV), a proximally-enriched luminal population (LumP) that is not lobe-specific, and a periurethral population (PrU) that shares both basal and luminal features. Functional analyses suggest that LumP and PrU cells have multipotent progenitor activity in organoid formation and ti...
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Cancer Biology Stem Cells and Regenerative Medicine Source Type: research

Nutrient levels and trade-offs control diversity in a serial dilution ecosystem
Microbial communities feature an immense diversity of species and this diversity is linked to outcomes ranging from ecosystem stability to medical prognoses. Yet the mechanisms underlying microbial diversity are under debate. While simple resource-competition models don't allow for coexistence of a large number of species, it was recently shown that metabolic trade-offs can allow unlimited diversity. Does this diversity persist with more realistic, intermittent nutrient supply? Here, we demonstrate theoretically that in serial dilution culture, metabolic trade-offs allow for high diversity. When a small amount of nutrient ...
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Ecology Physics of Living Systems Source Type: research

Dichotomous role of the human mitochondrial Na < sup > + < /sup > /Ca < sup > 2+ < /sup > /Li < sup > + < /sup > exchanger NCLX in colorectal cancer growth and metastasis
Despite the established role of mitochondria in cancer, the mechanisms by which mitochondrial Ca2+ (mtCa2+) regulates tumorigenesis remain incompletely understood. The crucial role of mtCa2+ in tumorigenesis is highlighted by altered expression of proteins mediating mtCa2+ uptake and extrusion in cancer. Here, we demonstrate decreased expression of the mitochondrial Na+/Ca2+/Li+exchanger NCLX (SLC8B1) in human colorectal tumors and its association with advanced-stage disease in patients. Downregulation of NCLX causes mtCa2+ overload, mitochondrial depolarization, decreased expression of cell-cycle genes and reduced tumor s...
Source: eLife - September 11, 2020 Category: Biomedical Science Tags: Structural Biology and Molecular Biophysics Source Type: research

Atg1 kinase in fission yeast is activated by Atg11-mediated dimerization and cis-autophosphorylation
Autophagy is a proteolytic pathway conserved from yeasts to mammals. Atg1 kinase is essential for autophagy but how its activity is controlled remains insufficiently understood. Here, we show that, in the fission yeastSchizosaccharomyces pombe, Atg1 kinase activity requires Atg11, the ortholog of mammalian FIP200/RB1CC1, but does not require Atg13, Atg17, or Atg101. Remarkably, a 62-amino-acid region of Atg11 is sufficient for the autophagy function of Atg11 and for supporting the Atg1 kinase activity. This region harbors an Atg1-binding domain and a homodimerization domain. Dimerizing Atg1 is the main role of Atg11, as it...
Source: eLife - September 10, 2020 Category: Biomedical Science Tags: Cell Biology Source Type: research

The host exosome pathway underpins biogenesis of the human cytomegalovirus virion
Human Cytomegalovirus (HCMV) infects over half the world's population, is a leading cause of congenital birth defects, and poses serious risks for immuno-compromised individuals. To expand the molecular knowledge governing virion maturation, we analysed HCMV virions using proteomics, and identified a significant proportion of host exosome constituents. To validate this acquisition, we characterized exosomes released from uninfected cells, and demonstrated that over 99% of the protein cargo was subsequently incorporated into HCMV virions during infection. This suggested a common membrane origin, and utilization of host exos...
Source: eLife - September 10, 2020 Category: Biomedical Science Tags: Microbiology and Infectious Disease Source Type: research

Dissecting the immunosuppressive tumor microenvironments in Glioblastoma-on-a-Chip for optimized PD-1 immunotherapy
Programmed cell death protein-1 (PD-1) checkpoint immunotherapy efficacy remains unpredictable in glioblastoma (GBM) patients due to the genetic heterogeneity and immunosuppressive tumor microenvironments. Here, we report a microfluidics-based, patient-specific ‘GBM-on-a-Chip’ microphysiological system to dissect the heterogeneity of immunosuppressive tumor microenvironments and optimize anti-PD-1 immunotherapy for different GBM subtypes. Our clinical and experimental analyses demonstrated that molecularly distinct GBM subtypes have distinct epigenetic and immune signatures that may lead to different immunosupp...
Source: eLife - September 10, 2020 Category: Biomedical Science Tags: Cancer Biology Physics of Living Systems Source Type: research

Vascular dimorphism ensured by regulated proteoglycan dynamics favors rapid umbilical artery closure at birth
The umbilical artery lumen closes rapidly at birth, preventing neonatal blood loss, whereas the umbilical vein remains patent longer. Here, analysis of umbilical cords from humans and other mammals identified differential arterial-venous proteoglycan dynamics as a determinant of these contrasting vascular responses. The umbilical artery, but not the vein, has an inner layer enriched in the hydrated proteoglycan aggrecan, external to which lie contraction-primed smooth muscle cells (SMC). At birth, SMC contraction drives inner layer buckling and centripetal displacement to occlude the arterial lumen, a mechanism revealed by...
Source: eLife - September 10, 2020 Category: Biomedical Science Tags: Computational and Systems Biology Developmental Biology Source Type: research

SOX11 promotes epithelial/mesenchymal hybrid state and alters tropism of invasive breast cancer cells
SOX11 is an embryonic mammary epithelial marker that is normally silenced prior to birth. HighSOX11 levels in breast tumours are significantly associated with distant metastasis and poor outcome in breast cancer patients. Here, we show that SOX11 confers distinct features to ER-negative DCIS.com breast cancer cells, leading to populations enriched with highly plastic hybrid epithelial/mesenchymal cells, which display invasive features and alterations in metastatic tropism when xenografted into mice. We found that SOX11+DCIS tumour cells metastasize to brain and bone at greater frequency and to lungs at lower frequency comp...
Source: eLife - September 10, 2020 Category: Biomedical Science Tags: Cancer Biology Developmental Biology Source Type: research

Soluble collectin-12 mediates C3-independent docking of properdin that activates the alternative pathway of complement
In conclusion, a prerequisite for properdin binding and in situ C3bBb assembly was the initial docking of sCL-12. This implies a new important function of properdin in host defence bridging pattern recognition and specific AP activation. (Source: eLife)
Source: eLife - September 10, 2020 Category: Biomedical Science Tags: Immunology and Inflammation Microbiology and Infectious Disease Source Type: research

Response to comment on 'Lack of evidence for associative learning in pea plants'
In 2016 Gagliano et al. reported evidence for associative learning in plants (Gagliano et al., 2016). A subsequent attempt to replicate this finding by the present author was not successful (Markel, 2020). Gagliano et al. attribute this lack of replication to differences in the experimental set-ups used in the original work and the replication attempt (Gagliano et al., 2020). Here, based on a comparison of the two set-ups, I argue that these differences are unable to explain the lack of replication in Markel, 2020. (Source: eLife)
Source: eLife - September 10, 2020 Category: Biomedical Science Tags: Plant Biology Source Type: research

Comment on 'Lack of evidence for associative learning in pea plants'
In 2016 we reported evidence for associative learning in plants (Gagliano et al., 2016). In view of the far-reaching implications of this finding we welcome the attempt made by Markel to replicate our study (Markel, 2020). However, as we discuss here, the protocol employed by Markel was unsuitable for testing for associative learning. (Source: eLife)
Source: eLife - September 10, 2020 Category: Biomedical Science Tags: Ecology Plant Biology Source Type: research

Minimally dependent activity subspaces for working memory and motor preparation in the lateral prefrontal cortex
The lateral prefrontal cortex is involved in the integration of multiple types of information, including working memory and motor preparation. However, it is not known how downstream regions can extract one type of information without interference from the others present in the network. Here, we show that the lateral prefrontal cortex of non-human primates contains two minimally dependent low-dimensional subspaces: one that encodes working memory information, and another that encodes motor preparation information. These subspaces capture all the information about the target in the delay periods, and the information in both...
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Neuroscience Source Type: research

Speciation and the developmental alarm clock
New species arise as the genomes of populations diverge. The developmental ‘alarm clock’ of speciation sounds off when sufficient divergence in genetic control of development leads hybrid individuals to infertility or inviability, the world awoken to the dawn of new species with intrinsic post-zygotic reproductive isolation. Some developmental stages will be more prone to hybrid dysfunction due to how molecular evolution interacts with the ontogenetic timing of gene expression. Considering the ontogeny of hybrid incompatibilities provides a profitable connection between ‘evo-devo’ and speciation gen...
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Developmental Biology Genetics and Genomics Source Type: research

Nurturing nature
Mutant zebrafish exhibit different behaviours depending on the genetic background of the fish they were raised with. (Source: eLife)
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Ecology Neuroscience Source Type: research

Genetic variation in the social environment affects behavioral phenotypes of oxytocin receptor mutants in zebrafish
Oxytocin-like peptides have been implicated in the regulation of a wide range of social behaviors across taxa. On the other hand, the social environment, which is composed of conspecifics that may vary in their genotypes, also influences social behavior, creating the possibility for indirect genetic effects. Here, we used a zebrafish oxytocin receptor knockout line to investigate how the genotypic composition of the social environment (Gs) interacts with the oxytocin genotype of the focal individual (Gi) in the regulation of its social behavior. For this purpose, we have raised wild-type or knock-out zebrafish in either wi...
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Ecology Neuroscience Source Type: research

Neurofascin and Kv7.3 are delivered to somatic and axon terminal surface membranes en route to the axon initial segment
This study reveals how key proteins are delivered to the AIS and thereby how they may contribute to its functional plasticity. (Source: eLife)
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Neuroscience Source Type: research

Breakage of the Oligomeric CaMKII Hub by the Regulatory Segment of the Kinase
Ca2+/calmodulin dependent protein kinase II (CaMKII) is an oligomeric enzyme with crucial roles in neuronal signaling and cardiac function. Previously, we showed that activation of CaMKII triggers the exchange of subunits between holoenzymes, potentially increasing the spread of the active state (Stratton et al. 2014; Bhattacharyya et al. 2016). Using mass spectrometry, we show now that unphosphorylated and phosphorylated peptides derived from the CaMKII- α regulatory segment bind to the CaMKII-α hub and break it into smaller oligomers. Molecular dynamics simulations show that the regulatory segments dock spont...
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Computational and Systems Biology Source Type: research

Nonlinearities between inhibition and T-type calcium channel activity bidirectionally regulate thalamic oscillations
Absence seizures result from 3-5 Hz generalized thalamocortical oscillations that depend on highly regulated inhibitory neurotransmission in the thalamus. Efficient reuptake of the inhibitory neurotransmitter GABA is essential, and reuptake failure worsens human seizures. Here, we show that blocking GABA transporters (GATs) in acute rat brain slices containing key parts of the thalamocortical seizure network modulates epileptiform activity. As expected, we found that blocking either GAT1 or GAT3 prolonged oscillations. However, blocking both GATs unexpectedly suppressed oscillations. Integrating experimental observations i...
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Computational and Systems Biology Neuroscience Source Type: research

Natural variation in autumn expression is the major adaptive determinant distinguishing Arabidopsis < i > FLC < /i > haplotypes
InArabidopsis thaliana, winter is registered during vernalization through the temperature-dependent repression and epigenetic silencing of floral repressorFLOWERING LOCUS C (FLC). Natural Arabidopsis accessions show considerable variation in vernalization. However, which aspect of theFLCrepression mechanism is most important for adaptation to different environments is unclear. By analyzingFLC dynamics in natural variants and mutants throughout winter in three field sites, we find that autumnalFLCexpression, rather than epigenetic silencing, is the major variable conferred by the distinct ArabidopsisFLC haplotypes. This var...
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Chromosomes and Gene Expression Plant Biology Source Type: research

Histone deposition pathways determine the chromatin landscapes of H3.1 and H3.3 K27M oncohistones
Lysine 27-to-methionine (K27M) mutations in the H3.1 or H3.3 histone genes are characteristic of pediatric diffuse midline gliomas (DMGs). These oncohistone mutations dominantly inhibit histone H3K27 trimethylation and silencing, but it is unknown how oncohistone type affects gliomagenesis. We show that the genomic distributions of H3.1 and H3.3 oncohistones in human patient-derived DMG cells are consistent with the DNA replication-coupled deposition of histone H3.1 and the predominant replication-independent deposition of histone H3.3. Although H3K27 trimethylation is reduced for both oncohistone types, H3.3K27M-bearing c...
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Cancer Biology Chromosomes and Gene Expression Source Type: research

Topology-driven protein-protein interaction network analysis detects genetic sub-networks regulating reproductive capacity
Understanding the genetic regulation of organ structure is a fundamental problem in developmental biology. Here, we use egg-producing structures of insect ovaries, called ovarioles, to deduce systems-level gene regulatory relationships from quantitative functional genetic analysis. We previously showed that Hippo signalling, a conserved regulator of animal organ size, regulates ovariole number inDrosophila melanogaster. To comprehensively determine how Hippo signalling interacts with other pathways in this regulation, we screened all known signalling pathway genes, and identified Hpo-dependent and Hpo-independent signallin...
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Computational and Systems Biology Developmental Biology Source Type: research

Long ascending propriospinal neurons provide flexible, context-specific control of interlimb coordination
Within the cervical and lumbar spinal enlargements, central pattern generating (CPG) circuitry produces the rhythmic output necessary for limb coordination during locomotion. Long propriospinal neurons that inter-connect these CPGs are thought to secure hindlimb-forelimb coordination, ensuring that diagonal limb pairs move synchronously while the ipsilateral limb pairs move out-of-phase during stepping. Here, we show that silencing long ascending propriospinal neurons (LAPNs) that interconnect the lumbar and cervical CPGs disrupts left-right limb coupling of each limb pair in the adult rat during overground locomotion on a...
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Neuroscience Source Type: research

CB < sub > 1 < /sub > receptor-mediated inhibitory LTD triggers presynaptic remodeling via protein synthesis and ubiquitination
Long-lasting forms of postsynaptic plasticity commonly involve protein synthesis-dependent structural changes of dendritic spines. However, the relationship between protein synthesis and presynaptic structural plasticity remains unclear. Here, we investigated structural changes in cannabinoid-receptor 1 (CB1)-mediated long-term depression of inhibitory transmission (iLTD), a form of presynaptic plasticity that involves a protein synthesis-dependent long-lasting reduction in GABA release. We found that CB1-iLTD in acute rat hippocampal slices was associated with protein synthesis-dependent presynaptic structural changes. Us...
Source: eLife - September 9, 2020 Category: Biomedical Science Tags: Neuroscience Source Type: research

Direct reprogramming of human smooth muscle and vascular endothelial cells reveals defects associated with aging and Hutchinson-Gilford progeria syndrome
Vascular dysfunctions are a common feature of multiple age-related diseases. However, modeling healthy and pathological aging of the human vasculature represents an unresolved experimental challenge. Here, we generated induced vascular endothelial cells (iVECs) and smooth muscle cells (iSMCs) by direct reprogramming of healthy human fibroblasts from donors of different ages and Hutchinson-Gilford Progeria Syndrome (HGPS) patients. iVECs induced from old donors revealed upregulation ofGSTM1 andPALD1, genes linked to oxidative stress, inflammation and endothelial junction stability, as vascular aging markers. A functional as...
Source: eLife - September 8, 2020 Category: Biomedical Science Tags: Medicine Source Type: research

Fibrodysplasia ossificans progressiva mutant ACVR1 signals by multiple modalities in the developing zebrafish
Fibrodysplasia ossificans progressiva (FOP) is a rare human genetic disorder characterized by altered skeletal development and extraskeletal ossification. All cases of FOP are caused by activating mutations in the type I BMP/TGF β cell surface receptor ACVR1, which over-activates signaling through phospho-Smad1/5 (pSmad1/5). To investigate the mechanism by which FOP-ACVR1 enhances pSmad1/5 activation, we used zebrafish embryonic dorsoventral (DV) patterning as an assay for BMP signaling. We determined that the FOP mutants ACVR1-R206H and -G328R do not require their ligand binding domain to over-activate BMP signaling ...
Source: eLife - September 8, 2020 Category: Biomedical Science Tags: Developmental Biology Source Type: research

A perspective on HPK1 as a novel immuno-oncology drug target
In this perspective review, the role Hematopoietic Progenitor Kinase 1 (HPK1) in tumor immunity will be reviewed, with special emphasis on how T cells are negatively-regulated at different junctures of cancer-immunity cycle by this regulatory kinase. The review will highlight the strengths and weaknesses of HPK1 as a candidate target for novel immuno-oncology (IO) drug development that is centered on the use of small molecule kinase inhibitor to modulate the immune response against cancer. Such a therapeutic approach, if proven successful, could supplement the cancer cell-centric standard of care therapies in order to full...
Source: eLife - September 8, 2020 Category: Biomedical Science Tags: Cancer Biology Immunology and Inflammation Source Type: research

A regulatory pathway that selectively up-regulates elongasome function in the absence of class A PBPs
Bacteria surround themselves with peptidoglycan, an adaptable enclosure that contributes to cell shape and stability. Peptidoglycan assembly relies on penicillin-binding proteins (PBPs) acting in concert with SEDS-family transglycosylases RodA and FtsW, which support cell elongation and division respectively. InBacillus subtilis, cells lacking all four PBPs with transglycosylase activity (aPBPs) are viable. Here, we show that the alternative sigma factor σI is essential in the absence of aPBPs. Defects in aPBP-dependent wall synthesis are compensated by σI-dependent upregulation of an MreB homolog, MreBH, which...
Source: eLife - September 8, 2020 Category: Biomedical Science Tags: Genetics and Genomics Source Type: research

Non-thalamic origin of zebrafish sensory nuclei implies convergent evolution of visual pathways in amniotes and teleosts
Ascending visual projections similar to the mammalian thalamocortical pathway are found in a wide range of vertebrate species, but their homology is debated. To get better insights into their evolutionary origin, we examined the developmental origin of a thalamic-like sensory structure of teleosts, the preglomerular complex (PG), focusing on the visual projection neurons. Similarly to the tectofugal thalamic nuclei in amniotes, the lateral nucleus of PG receives tectal information and projects to the pallium. However, our cell lineage study in zebrafish reveals that the majority of PG cells are derived from the midbrain, u...
Source: eLife - September 8, 2020 Category: Biomedical Science Tags: Neuroscience Source Type: research

EphrinB2-EphB4 signalling provides Rho-mediated homeostatic control of lymphatic endothelial cell junction integrity
Endothelial integrity is vital for homeostasis and adjusted to tissue demands. Although fluid uptake by lymphatic capillaries is a critical attribute of the lymphatic vasculature, the barrier function of collecting lymphatic vessels is also important by ensuring efficient fluid drainage as well as lymph node delivery of antigens and immune cells. Here, we identified the transmembrane ligand EphrinB2 and its receptor EphB4 as critical homeostatic regulators of collecting lymphatic vessel integrity. Conditional gene deletion in mice revealed that EphrinB2/EphB4 signalling is dispensable for blood endothelial barrier function...
Source: eLife - September 8, 2020 Category: Biomedical Science Tags: Cell Biology Developmental Biology Source Type: research

Marked synergy by vertical inhibition of EGFR signaling in NSCLC spheroids shows SOS1 is a therapeutic target in EGFR-mutated cancer
Drug treatment of 3D cancer spheroids more accurately reflects in vivo therapeutic responses compared to adherent culture studies. In EGFR-mutated lung adenocarcinoma, EGFR-TKIs show enhanced efficacy in spheroid cultures. Simultaneous inhibition of multiple parallel RTKs further enhances EGFR-TKI effectiveness. We show that the common RTK signaling intermediate SOS1 was required for 3D spheroid growth of EGFR-mutated NSCLC cells. Using two distinct measures of pharmacologic synergy, we demonstrated that SOS1 inhibition strongly synergized with EGFR-TKI treatment only in 3D spheroid cultures. Combined EGFR- and SOS1-inhibi...
Source: eLife - September 8, 2020 Category: Biomedical Science Tags: Cancer Biology Source Type: research

Genome duplication in < i > Leishmania major < /i > relies on persistent subtelomeric DNA replication
DNA replication is needed to duplicate a cell's genome in S-phase and segregate it during cell division. Previous work inLeishmania detected DNA replication initiation at just a single region in each chromosome, an organisation predicted to be insufficient for complete genome duplication within S-phase. Here, we show that acetylated histone H3 (AcH3), base J and a kinetochore factor colocalise in each chromosome at only a single locus, which corresponds with previously mapped DNA replication initiation regions and is demarcated by localised G/T skew and G4 patterns. In addition, we describe previously undetected subtelomer...
Source: eLife - September 8, 2020 Category: Biomedical Science Tags: Genetics and Genomics Microbiology and Infectious Disease Source Type: research

Firing rate-dependent phase responses of Purkinje cells support transient oscillations
Both spike rate and timing can transmit information in the brain. Phase response curves (PRCs) quantify how a neuron transforms input to output by spike timing. PRCs exhibit strong firing-rate adaptation, but its mechanism and relevance for network output are poorly understood. Using our Purkinje cell (PC) model, we demonstrate that the rate adaptation is caused by rate-dependent subthreshold membrane potentials efficiently regulating the activation of Na+ channels. Then, we use a realistic PC network model to examine how rate-dependent responses synchronize spikes in the scenario of reciprocal inhibition-caused high-frequ...
Source: eLife - September 8, 2020 Category: Biomedical Science Tags: Neuroscience Source Type: research

Empathic pain evoked by sensory and emotional-communicative cues share common and process-specific neural representation
Pain empathy can be evoked by multiple cues, particularly observation of acute pain inflictions or facial expressions of pain. Previous studies suggest that these cues commonly activate the insula and anterior cingulate, yet vicarious pain encompass pain-specific responses as well as unspecific processes (e.g., arousal) and overlapping activations are not sufficient to determine process-specific shared neural representations. We employed multivariate pattern analyses to fMRI data acquired during observation of noxious stimulation of body limbs (NS) and painful facial expressions (FE) and found spatially and functionally si...
Source: eLife - September 7, 2020 Category: Biomedical Science Tags: Neuroscience Source Type: research

Removing unwanted variation with CytofRUV to integrate multiple CyTOF datasets
Mass cytometry (CyTOF) is a technology that has revolutionised single cell biology. By detecting over 40 proteins on millions of single cells, CyTOF allows the characterisation of cell subpopulations in unprecedented detail. However most CyTOF studies require the integration of data from multiple CyTOF batches usually acquired on different days and possibly at different sites. To date, the integration of CyTOF datasets remains a challenge due to technical differences arising in multiple batches. To overcome this limitation, we developed an approach called CytofRUV for analysing multiple CyTOF batches which includes an R-Sh...
Source: eLife - September 7, 2020 Category: Biomedical Science Tags: Computational and Systems Biology Source Type: research