bluuebunny/crossref_metadata_2025_split huggingface dataset:
BAF facilitates interphase nuclear membrane repair through recruitment of nuclear transmembrane proteins
Authors: Young Alexandra M. , Gunn Amanda L. , Hatch Emily M. 
Published: January 2020

AbstractNuclear membrane rupture during interphase occurs in a variety of cell contexts, both healthy and pathological. Membrane ruptures can be rapidly repaired, but these mechanisms are still unclear. Here we show BAF, a nuclear envelope protein that shapes chromatin and recruits membrane proteins in mitosis, also facilitates nuclear membrane repair in interphase, in part through recruitment of the nuclear membrane proteins emerin and LEMD2 to rupture sites. Characterization of GFP-BAF accumulation at nuclear membrane rupture sites confirmed BAF is a fast, accurate, and persistent mark of nucleus rupture whose kinetics are partially dictated by membrane resealing. BAF depletion significantly delayed nuclear membrane repair, with a larger effect on longer ruptures. This phenotype could be rescued by GFP-BAF, but not by a BAF mutant lacking the LEM-protein binding domain. Depletion of the BAF interactors LEMD2 or emerin, and to a lesser extent lamin A/C, increased the duration of nucleus ruptures, consistent with LEM-protein binding being a key function of BAF during membrane repair. Overall our results suggest a model where BAF is critical for timely repair of large ruptures in the nuclear membrane, potentially by facilitating membrane attachment to the rupture site.
Rare protein coding variants implicate genes involved in risk of suicide death
Authors: DiBlasi Emily , Shabalin Andrey A. , Monson Eric T. , Keeshin Brooks R. , Bakian Amanda V. , Kirby Anne V. , Ferris Elliott , Chen Danli , William Nancy , Gaj Eoin , Klein Michael , Jerominski Leslie , Callor W. Brandon , Christensen Erik , Gray Douglas , Smith Ken R. , Fraser Alison , Yu Zhe ,   PsychChip Investigators of the Psychiatric Genomics Consortium, Camp Nicola J. , Stahl Eli A. , Li Qingqin S. , Docherty Anna R. , Coon Hilary 
Published: January 2020

ABSTRACTSuicide death is a worldwide health crisis, claiming close to 800,000 lives per year. Recent evidence suggests that prediction and prevention challenges may be aided by discoveries of genetic risk factors. Here we focus on the role of rare (MAF <1%), putatively functional single nucleotide polymorphisms (SNPs) in suicide death using the large genetic resources available in the Utah Suicide Genetic Risk Study (USGRS). We conducted a single-variant association analysis of 30,377 rare putatively functional SNPs present on the PsychArray genotyping array in 2,672 USGRS suicides of non-Finnish European (NFE) ancestry and 51,583 publicly available NFE controls from gnomAD, with additional follow-up analyses using an independent control sample of 21,324 NFE controls from the Psychiatric Genomics Consortium. SNPs underwent rigorous quality control, and among SNPs meeting significance thresholds, we considered only those that were validated in sequence data. We identified five novel, high-impact, rare SNPs with significant associations with suicide death (SNAPC1, rs75418419;TNKS1BP1, rs143883793;ADGRF5, rs149197213;PER1, rs145053802; andESS2, rs62223875). BothPER1andSNAPC1have other supporting gene-level evidence of suicide risk, and an association with bipolar disorder has been reported forPER1and with schizophrenia forPER1, TNKS1BP1, andESS2. Three genes (PER1, TNKS1BP1, andADGRF5), with additional genes implicated by GWAS studies on suicidal behavior, showed significant enrichment in immune system, homeostatic and signal transduction processes. Pain, depression, and accidental trauma were the most prevalent phenotypes in electronic medical record data for the categories assessed. These findings suggest an important role for rare variants in suicide risk and provide new insights into the genetic architecture of suicide death. Furthermore, we demonstrate the added utility of careful assessment of genotyping arrays in rare variant discovery.
Spatially compartmentalized phase regulation of a Ca2+-cAMP-PKA oscillatory circuit
Authors: Tenner Brian , Getz Michael , Ross Brian , Ohadi Donya , Bohrer Christopher H. , Greenwald Eric , Mehta Sohum , Xiao Jie , Rangamani Padmini , Zhang Jin 
Published: January 2020

ABSTRACTSignaling networks are spatiotemporally organized in order to sense diverse inputs, process information, and carry out specific cellular tasks. In pancreatic β cells, Ca2+, cyclic adenosine monophosphate (cAMP), and Protein Kinase A (PKA) exist in an oscillatory circuit characterized by a high degree of feedback, which allows for specific signaling controls based on the oscillation frequencies. Here, we describe a novel mode of regulation within this circuit involving a spatial dependence of the relative phase between cAMP, PKA, and Ca2+. We show that nanodomain clustering of Ca2+-sensitive adenylyl cyclases drives oscillations of local cAMP levels to be precisely in-phase with Ca2+oscillations, whereas Ca2+-sensitive phosphodiesterases maintain out-of-phase oscillations outside of the nanodomain, representing a striking example and novel mechanism of cAMP compartmentation. Disruption of this precise in-phase relationship perturbs Ca2+oscillations, suggesting that the relative phase within an oscillatory circuit can encode specific functional information. This example of a signaling nanodomain utilized for localized tuning of an oscillatory circuit has broad implications for the spatiotemporal regulation of signaling networks.
ChiS is a noncanonical DNA-binding hybrid sensor kinase that directly regulates the chitin utilization program inVibrio cholerae
Authors: Klancher Catherine A. , Yamamoto Shouji , Dalia Triana N. , Dalia Ankur B. 
Published: January 2020

AbstractTwo-component signal transductionsystems (TCSs) represent a major mechanism that bacteria use to sense and respond to their environment. Prototypical TCSs are composed of a membrane-embedded histidine kinase (HK), which senses an environmental stimulus and subsequently phosphorylates a cognate partner protein called a response regulator (RR) that regulates gene expression in a phosphorylation-dependent manner.Vibrio choleraeuses the hybrid HK ChiS to activate the expression of the chitin utilization program, which is critical for the survival of this facultative pathogen in its aquatic reservoir. A cognate RR for ChiS has not been identified and the mechanism of ChiS-dependent signal transduction remains unclear. Here, we show that ChiS is a noncanonical membrane-embedded one-component system that can both sense chitin and directly regulate gene expression via a cryptic DNA binding domain. Unlike prototypical TCSs, we find that ChiS DNA binding is diminished, rather than stimulated, by phosphorylation. Finally, we provide evidence that ChiS likely activates gene expression by directly recruiting RNA polymerase. Together, this work addresses the mechanism of action for a major transcription factor inV. choleraeand highlights the versatility of signal transduction systems in bacterial species.Significance StatementFrom bacteria to humans, the ability to properly respond to environmental cues is critical for survival. The cholera pathogenVibrio choleraeuses one protein, ChiS, to sense chitin in its environmental reservoir to regulate the expression of genes that are critical for the survival and evolution of this pathogen in this niche. Here, we study how the chitin sensor ChiS works, and discover that it regulates gene expression in an unexpected and unorthodox manner. Thus, this study uncovers how the major regulator ChiS works in this important human pathogen and highlights the versatile mechanisms that living systems use to respond to their environment.
Bariatric surgery reveals a gut-restricted TGR5 agonist that exhibits anti-diabetic effects
Authors: Chaudhari Snehal N. , Harris David A. , Aliakbarian Hassan , Henke Matthew T. , Subramaniam Renuka , Vernon Ashley H. , Tavakkoli Ali , Sheu Eric G. , Devlin A. Sloan 
Published: January 2020

AbstractBariatric surgery, the most effective treatment for obesity and type 2 diabetes, is consistently associated with increased levels of the incretin hormone GLP-1 and changes in overall levels of circulating bile acids. The levels of individual bile acids in the GI tract following surgery, however, have remained largely unstudied. Using UPLC-MS-based quantification, we observed an increase in an endogenous bile acid, cholic acid-7-sulfate (CA7S), in the GI tract of both mice and humans after sleeve gastrectomy. We show that CA7S is a TGR5 agonist that induces GLP-1 secretion in vitro and in vivo and that CA7S administration increases glucose tolerance in insulin-resistant mice in a GLP-1 receptor-dependent manner. CA7S remains gut-restricted, minimizing off-target effects previously observed for TGR5 agonists absorbed into circulation. By studying changes in individual metabolites following surgery, this study has revealed a naturally occurring TGR5 agonist that exerts systemic glucoregulatory effects while remaining confined to the gut.
Highly Multiplexed Single-Cell Full-Length cDNA Sequencing of human immune cells with 10X Genomics and R2C2
Authors: Volden Roger , Vollmers Christopher 
Published: January 2020

AbstractSingle cell transcriptome analysis elucidates facets of cell biology that have been previously out of reach. However, the high-throughput analysis of thousands of single cell transcriptomes has been limited by sample preparation and sequencing technology. High-throughput single cell analysis today is facilitated by protocols like the 10X Genomics platform or Drop-Seq which generate cDNA pools in which the origin of a transcript is encoded at its 5’ or 3’ end. These cDNA pools are most often analyzed by short read Illumina sequencing which can identify the cellular origin of a transcript and what gene it was transcribed from. However, these methods fail to retrieve isoform information. In principle, cDNA pools prepared using these approaches can be analyzed with Pacific Biosciences and Oxford Nanopore long-read sequencers to retrieve isoform information but current implementations rely heavily on Illumina short-reads for analysis in addition to long reads. Here, we used R2C2 to sequence and demultiplex 12 million full-length cDNA molecules generated by the 10X Chromium platform from ∼3000 peripheral blood mononuclear cells (PBMCs). We used these reads to – independent from Illumina data – cluster cells into B cells, T cells, and Monocytes and generate isoform-level transcriptomes for these cell types. We also generated isoform-level transcriptomes for all single cells and used this information to identify a wide range of isoform diversity between genes. Finally, we also designed a computational workflow to extract paired adaptive immune receptors – T cell receptor and B cell receptor (TCR and BCR) – sequences unique to each T and B cell. This work represents a new, simple, and powerful approach that – using a single sequencing method – can extract an unprecedented amount of information from thousands of single cells.
Detection of urease and carbonic anhydrase activity using a rapid and economical field test to assess microbially-induced carbonate precipitation
Authors: Ferrer Fernando Medina , Hobart Kathryn , Bailey Jake V. 
Published: January 2020

ABSTRACTMicrobial precipitation of calcium carbonate has diverse engineering applications, from building and soil restoration, to carbon sequestration. Urease-mediated ureolysis and CO2(de)hydration by carbonic anhydrase (CA) are known for their potential to precipitate carbonate minerals, yet many microbial community studies rely on marker gene or metagenomic approaches that are unable to determinein situactivity. Here, we developed fast and cost-effective tests for the field detection of urease and CA activity using pH-sensitive strips inside microcentrifuge tubes that change color in response to the reaction products of urease (NH3) and CA (CO2). Samples from a saline lake, a series of calcareous fens, and ferrous springs were assayed in the field, finding relatively high urease activity in lake samples, whereas CA activity was only detected in a ferrous spring. Incubations of lake microbes with urea resulted in significantly higher CaCO3precipitation compared to incubations with a urease inhibitor. Therefore, the rapid assay indicated an on-site active metabolism potentially mediating carbonate mineralization. Field urease and CA activity assays complement molecular approaches and facilitate the search for carbonate-precipitating microbes and theirin situactivity, which could be applied toward agriculture, engineering and carbon sequestration technologies.
Chaperone mediated coupling of subunit availability to activation of flagellar Type III Secretion
Authors: Bryant Owain J. , Chung Betty Y-W. , Fraser Gillian M. 
Published: January 2020

AbstractBacterial flagellar subunits are exported across the cell membrane by the flagellar Type III Secretion System (fT3SS), powered by the proton motive force (pmf) and a specialized ATPase that enables the flagellar export gate to utilise the pmf electric potential (ΔΨ). Export gate activation is mediated by the ATPase stalk, FliJ, but how this process is regulated to prevent wasteful dissipation of pmf in the absence of subunit cargo is not known. Here, we show that FliJ activation of the export gate is regulated by flagellar export chaperones. FliJ binds unladen chaperones and, using novel chaperone variants specifically defective for FliJ binding, we show that disruption of this interaction attenuates motility and cognate subunit export. We demonstrate in vitro that chaperones and the FlhA export gate component compete for binding to FliJ, and show in vivo that unladen chaperones, which would be present in the cell when subunit levels are low, sequester FliJ to prevent activation of the export gate and attenuate subunit export. Our data indicate a mechanism whereby chaperones couple availability of subunit cargo to pmf-driven export by the fT3SS.
Slow drift of neural activity as a signature of impulsivity in macaque visual and prefrontal cortex
Authors: Cowley Benjamin R. , Snyder Adam C. , Acar Katerina , Williamson Ryan C. , Yu Byron M. , Smith Matthew A. 
Published: January 2020

AbstractAn animal’s decision depends not only on incoming sensory evidence but also on its fluctuating internal state. This internal state is a product of cognitive factors, such as fatigue, motivation, and arousal, but it is unclear how these factors influence the neural processes that encode the sensory stimulus and form a decision. We discovered that, over the timescale of tens of minutes during a perceptual decision-making task, animals slowly shifted their likelihood of reporting stimulus changes. They did this unprompted by task conditions. We recorded neural population activity from visual area V4 as well as prefrontal cortex, and found that the activity of both areas slowly drifted together with the behavioral fluctuations. We reasoned that such slow fluctuations in behavior could either be due to slow changes in how the sensory stimulus is processed or due to a process that acts independently of sensory processing. By analyzing the recorded activity in conjunction with models of perceptual decision-making, we found evidence for the slow drift in neural activity acting as an impulsivity signal, overriding sensory evidence to dictate the final decision. Overall, this work uncovers an internal state embedded in the population activity across multiple brain areas, hidden from typical trial-averaged analyses and revealed only when considering the passage of time within each experimental session. Knowledge of this cognitive factor was critical in elucidating how sensory signals and the internal state together contribute to the decision-making process.
Machine learning classification can reduce false positives in structure-based virtual screening
Authors: Adeshina Yusuf , Deeds Eric , Karanicolas John 
Published: January 2020

AbstractWith the recent explosion in the size of libraries available for screening, virtual screening is positioned to assume a more prominent role in early drug discovery’s search for active chemical matter. Modern virtual screening methods are still, however, plagued with high false positive rates: typically, only about 12% of the top-scoring compounds actually show activity when tested in biochemical assays. We argue that most scoring functions used for this task have been developed with insufficient thoughtfulness into the datasets on which they are trained and tested, leading to overly simplistic models and/or overtraining. These problems are compounded in the literature because none of the studies reporting new scoring methods have validated their model prospectively within the same study. Here, we report a new strategy for building a training dataset (D-COID) that aims to generate highly-compelling decoy complexes that are individually matched to available active complexes. Using this dataset, we train a general-purpose classifier for virtual screening (vScreenML) that is built on the XGBoost framework of gradient-boosted decision trees. In retrospective benchmarks, our new classifier shows outstanding performance relative to other scoring functions. We additionally evaluate the classifier in a prospective context, by screening for new acetylcholinesterase inhibitors. Remarkably, we find that nearly all compounds selected by vScreenML show detectable activity at 50 µM, with 10 of 23 providing greater than 50% inhibition at this concentration. Without any medicinal chemistry optimization, the most potent hit from this initial screen has an IC50 of 280 nM, corresponding to a Ki value of 173 nM. These results support using the D-COID strategy for training classifiers in other computational biology tasks, and for vScreenML in virtual screening campaigns against other protein targets. Both D-COID and vScreenML are freely distributed to facilitate such efforts.
Reconstruction of motor control circuits in adultDrosophilausing automated transmission electron microscopy
Authors: Maniates-Selvin Jasper T. , Hildebrand David Grant Colburn , Graham Brett J. , Kuan Aaron T. , Thomas Logan A. , Nguyen Tri , Buhmann Julia , Azevedo Anthony W. , Shanny Brendan L. , Funke Jan , Tuthill John C. , Lee Wei-Chung Allen 
Published: January 2020

SUMMARYMany animals use coordinated limb movements to interact with and navigate through the environment. To investigate circuit mechanisms underlying locomotor behavior, we used serial-section electron microscopy (EM) to map synaptic connectivity within a neuronal network that controls limb movements. We present a synapse-resolution EM dataset containing the ventral nerve cord (VNC) of an adult femaleDrosophila melanogaster. To generate this dataset, we developed GridTape, a technology that combines automated serial-section collection with automated high-throughput transmission EM. Using this dataset, we reconstructed 507 motor neurons, including all those that control the legs and wings. We show that a specific class of leg sensory neurons directly synapse onto the largest-caliber motor neuron axons on both sides of the body, representing a unique feedback pathway for fast limb control. We provide open access to the dataset and reconstructions registered to a standard atlas to permit matching of cells between EM and light microscopy data. We also provide GridTape instrumentation designs and software to make large-scale EM data acquisition more accessible and affordable to the scientific community.
The novel reversible LSD1 inhibitor SP-2577 promotes anti-tumor immunity in SWItch/Sucrose-NonFermentable (SWI/SNF) complex mutated ovarian cancer
Authors: Soldi Raffaella , Halder Tithi Ghosh , Weston Alexis , Thode Trason , Drenner Kevin , Lewis Rhonda , Kaadige Mohan R. , Srivastava Shreyesi , Ampanattu Sherin Daniel , del Villar Ryan Rodriguez , Lang Jessica , Vankayalapati Hariprasad , Weissman Bernard , Trent Jeffrey M. , Hendricks William P.D. , Sharma Sunil 
Published: January 2020

AbstractChromatin remodeling SWItch/Sucrose-NonFermentable (SWI/SNF) complexes, initially identified in yeast 20 years ago, are evolutionarily conserved multi-subunit protein complexes that use the energy from hydrolysis of adenosine triphosphate (ATP) to remodel nucleosome structure and modulate transcription. Mutations in proteins of SWI/SNF complexes occur in 20% of human cancers including ovarian cancer (OC). Approximately 50% of ovarian clear cell carcinoma (OCCC) carries mutations in the SWI/SNF subunit ARID1A while small cell carcinoma of the ovary hypercalcemic type (SCCOHT) is driven primarily by genetic inactivation of the SWI/SNF ATPase SMARCA4 (BRG1) alongside epigenetic silencing of the homolog ATPase SMARCA2 (BRM). Dual loss of these ATPases disrupts SWI/SNF chromatin remodeling activity and may also interfere with the function of other histone-modifying enzymes that associate with or are dependent on SWI/SNF activity. One such enzyme is lysine-specific histone demethylase 1 (LSD1/KDM1A) which regulates the chromatin landscape and gene expression by demethylating proteins, including histone H3. LSD1 associates with epigenetic complexes such as the nucleosome remodeling deacetylase complex (NuRD) and SWI/SNF to inhibit the transcription of genes involved in tumor suppression and cell differentiation. TGCA analysis of human cancers shows that LSD1 is highly expressed in SWI/SNF-mutated tumors. Further, SCCOHT and OCCC cell lines show low nM IC50s for the reversible LSD1 inhibitor SP-2577 (Seclidemstat, currently in clinical phase I trials), supporting that these SWI/SNF-deficient ovarian cancers are dependent on LSD1 activity. Recently, it has been also shown that inhibition of LSD1 stimulates interferon (IFN)-dependent anti-tumor immunity through induction of Endogenous Retroviruses Elements (ERVs) and may thereby overcome resistance to checkpoint blockade. Additionally, SCCOHTs have been shown to exhibit an immune-active tumor microenvironment with PD-L1 expression in both tumor and stromal cells that strongly correlated with T cell infiltration. Thus, in this study we investigated the ability of SP-2577 to promote anti-tumor immunity and T cell infiltration in SWI/SNF-mutant SCCOHT and OCCC models. Our data shows that the reversible LSD1 inhibitor SP-2577 stimulates IFN-dependent anti-tumor immunity in SCCOHT cellsin vitroin a 3D immune-organoid platform. Additionally, SP-2577 promoted the expression of PD-L1 in both SCCOHT and OCCC models. Together our findings suggest that SP-2577 and checkpoint inhibitors as a therapeutic combination may induce or augment immunogenic responses in these tumors.