Biology subjects

Chen, C.

Publications and source records attributed to Chen, C..

At least 559 records · Page 31Linked to original sources

bioRxiv2021

Deciphering Multi-way Interactions in the Human Genome

Chromatin architecture, a key regulator of gene expression, can be inferred using chromatin contact data from chromosome conformation capture, or Hi-C. However, classical Hi-C does not preserve multi-way contacts. Here we use long sequencing reads to map genome-wide multi-way contacts and investigate higher order chromatin organization in the human genome. We use hypergraph theory for data representation and analysis, and quantify higher order structures in neonatal fibroblasts, biopsied adult fibroblasts, and B lymphocytes. By integrating multi-way contacts with chromatin accessibility, gene expression, and transcription factor binding, we introduce a data-driven method to identify cell type-specific transcription clusters. We provide transcription factor-mediated functional building blocks for cell identity that serve as a global signature for cell types.

bioinformatics↗

bioRxiv2021

BubR1 recruitment to the kinetochore via Bub1 enhances Spindle Assembly Checkpoint signaling

During mitosis, unattached kinetochores in a dividing cell activate the Spindle Assembly Checkpoint (SAC) and delay anaphase onset by generating the anaphase-inhibitory Mitotic Checkpoint Complex (MCC). These kinetochores generate the MCC by recruiting MCC constituent proteins, including BubR1. In principle, BubR1 recruitment to signaling kinetochores should increase its local concentration and promote MCC formation. However, in human cells BubR1 is mainly thought to sensitize the SAC to silencing; whether BubR1 localization to signaling kinetochores per se enhances SAC signaling activity remains unknown. Therefore, we used ectopic SAC activation systems (eSAC) to isolate two molecules that recruit BubR1 to the kinetochore: the checkpoint protein Bub1 and the KI and MELT motifs in the kinetochore protein KNL1, and observed their contribution to eSAC signaling. Our quantitative analyses and mathematical modeling show that the Bub1-mediated BubR1 recruitment to the human kinetochore promotes SAC signaling and highlight BubR1s dual role of directly strengthening the SAC and indirectly silencing it.

cell biology↗

bioRxiv2021

Ontology-Aware Deep Learning Enables Novel Antibiotic Resistance Gene Discovery Towards Comprehensive Profiling of ARGs

Antibiotic resistance genes (ARGs) have emerged in pathogens and arousing a worldwide concern, which is estimated to cause millions of deaths each year globally. Accurately identifying and classifying ARGs is a formidable challenge in studying the generation and spread of antibiotic resistance. Current methods could identify close homologous ARGs, have limited utility for discovery of novel ARGs, thus rendering the profiling of ARGs incomprehensive. Here, an ontology-aware neural network (ONN) approach, ONN4ARG, is proposed for comprehensive ARG discovery. Systematic evaluation shows ONN4ARG is advanced than previous methods such as DeepARG in efficiency, accuracy, and comprehensiveness. Experiments using 200 million candidate microbial genes collected from 815 microbial community samples from diverse environments or hosts have resulted in 120,726 candidate ARGs, out of which more than 20% are not yet present in public databases. These comprehensive set of ARGs have clarified the environment-specific and host-specific patterns. The wet-experimental functional validation, together with structural investigation of docking sites, have also validated a novel streptomycin resistance gene from oral microbiome samples, confirming ONN4ARGs ability for novel ARGs identification. In summary, ONN4ARG is superior to existing methods in efficiency, accuracy, and comprehensiveness. It enables comprehensive ARG discovery, which is helpful towards a grand view of ARGs worldwide. ONN4ARG is available at https://github.com/HUST-NingKang-Lab/ONN4ARG, and online web service is available at http://onn4arg.xfcui.com/.

bioinformatics↗

bioRxiv2021

The tetrameric assembly of 2-aminomuconic acid dehydrogenase is a functional requirement of cofactor NAD+ binding

The bacterium Pseudomonas sp. AP-3 is able to use the environmental pollutant 2-aminophenol as its sole source of carbon, nitrogen, and energy. Eight genes (amnA, B, C, D, E, F, G, and H) encoding 2-aminophenol metabolizing enzymes are clustered into a single operon. 2-aminomuconic 6-semialdehyde dehydrogenase (AmnC), a member of the aldehyde dehydrogenase (ALDH) superfamily, is responsible for oxidizing 2-aminomuconic 6-semialdehyde to 2-aminomuconate. In contrast to many other members of the ALDH superfamily, the structural basis of the catalytic activity of AmnC remains elusive. Here, we present the crystal structure of AmnC, which displays a homotetrameric quaternary assembly that is directly involved in its enzymatic activity. The tetrameric state of AmnC in solution was also presented using small-angle X-ray scattering. The tetramerization of AmnC is mediated by the assembly of a protruding hydrophobic beta-strand motif and residues V121 and S123 located in the NAD+-binding domain of each subunit. Dimeric mutants of AmnC dramatically lose NAD+ binding affinity and enzyme activity, indicating that tetrameric assembly of AmnC is required for oxidizing the unstable metabolic intermediate 2-aminomuconic 6-semialdehyde to 2-aminomuconic acid in the 2-aminophenol metabolism pathway.

microbiology↗

bioRxiv2021

Effects of sub-threshold transcutaneous auricular vagus nerve stimulation on cerebral blood flow

BackgroundTranscutaneous auricular vagus nerve stimulation (taVNS) has shown promise as a non-invasive alternative to vagus nerve stimulation (VNS) with implantable devices, which has been used to treat drug-resistant epilepsy and treatment-resistant depression. Prior work has used functional MRI to investigate the brain response to taVNS, and more recent work has also demonstrated potential therapeutic effects of high-frequency sub-threshold taVNS in rheumatoid arthritis. However, no studies to date have measured the effects of high-frequency sub-threshold taVNS on cerebral blood flow (CBF). Objective/HypothesisThe objective of this study was to determine whether high-frequency (20 kHz) sub-threshold taVNS induces significant changes in CBF. MethodsArterial spin labeling (ASL) MRI scans were performed on 20 healthy subjects in a single-blind placebo-controlled repeated measures experimental design. The ASL scans were performed before and after 15 minutes of either sub-threshold taVNS treatment or a sham control. ResultstaVNS induced significant changes in CBF in the superior posterior cerebellum that were largely localized to bilateral Crus I and Crus II. Post hoc analyses showed that the changes were driven by a treatment-related decrease in CBF. ConclusionsFifteen minutes of high-frequency sub-threshold taVNS can induce sustained CBF decreases in the bilateral posterior cerebellum in a cohort of healthy subjects. This study lays the foundation for future studies in clinical popluations to assess whether similar effects can be observed and are related to treatment outcomes.

neuroscience↗

bioRxiv2021

Quercetin ameliorates mitochondrial dysfunction and mitigates methamphetamine-induced anxiety-like behavior

Methamphetamine (MA) abuse results in neurotoxic outcomes, including increased anxiety and depression, during both MA use and withdrawal. Although numerous studies have reported an association between MA exposure and anxiety, the underlying mechanism remains elusive. In this study, escalating dose of MA was used to establish an MA-treated mouse model presenting anxiety behavior. RNA seq was then performed to profile the gene expression patterns in the hippocampus (HIPP). Differentially expressed genes (DEGs) were identified and function enrichment analysis was conducted to explore the underlying mechanisms. Quercetin as an mitochondria protector was used in vivo and in vitro. The C57BL/6J mice were co-treated with 50 mg/kg Quercetin and escalating MA. Anxiety behavior was evaluated by utilizing the elevated plus maze and the open field test. Transmission electron microscopy and immunohistochemistry were conducted to study the pathology of MA-inducced anxiety. The effects of MA and Quercetin on astrocytes were investigated by fluorescence staining, transmission electron microscopy, flow cytometry, and oxygen consumption rate. Western blot and qPCR were performed to analyze altered protein and gene levels of HIPP in mice and astrtocytes. The results demonstrated that forteen upregulated differentially expressed genes were identified and significantly enriched in signaling pathways related to psychiatric disorders and mitochondrial function. Interestingly, we found that quercetin was able to alleviate MA-induced anxiety-like behavior by improving neuron number and mitochondria injury. Mechanistically, quercetin can mitigate aberrant mitochondrial morphology and mitochondrial dysfunction not only by decreasing the levels of total cytoplasmic reactive oxygen species (ROS), mitochondria-derived ROS (mtROS), and mitochondrial membrane potential (MMP), but also increasing the oxygen consumption rate (OCR) and mitochondrial ATP production in vitro, indicating Quercetin ameliorated MA-induced anxiety-like behavior by modifying mitochondrial morphology and function. Furthermore, quercetin reversed OPA1 and DRP1 expression in astrocytes, and mitigated astrocyte activation and the release of inflammatory factors, which can trigger neuronal apoptosis and synaptic loss. Taken together, we provided evidence showing that MA can induce anxiety-like behavior via the induction of oxidative stress and mitochondrial dysfunction. Quercetin exerted antipsychotic activity through mitochondrial modulation, suggesting its potential for further therapeutic development in MA-induced anxiety.

neuroscience↗

bioRxiv2021

Structural insight into molecular inhibitory mechanism of InsP6 on African Swine Fever Virus mRNA-decapping enzyme g5Rp

Removal of 5' cap on cellular mRNAs by the African Swine Fever Virus (ASFV) decapping enzyme g5R protein (g5Rp) is beneficial to viral gene expression during the early stages of infection. As the only nucleoside diphosphate linked moiety X (Nudix) decapping enzyme encoded in the ASFV genome, g5Rp works in both the degradation of cellular mRNA and hydrolyzation of the diphosphoinositol polyphosphates. Here, we report the structures of dimeric g5Rp and its complex with inositol hexakisphosphate (InsP6). The two g5Rp protomers interact head-to-head to form a dimer, and the dimeric interface is formed by extensive polar and nonpolar interactions. Each protomer composed a unique N-terminal helical domain and C-terminal classic Nudix domain. As a mRNA decapping enzyme, we identified key residues, including K8, K94, K95, K98, K175, R221, and K243 located on the substrate RNA binding interfaces of g5Rp, are important to RNA binding and decapping enzyme activity. Furthermore, we identified that the g5Rp-mediated mRNA decapping was inhibited by the InsP6. The g5Rp-InsP6 complex structure showed that the InsP6 molecules occupy the same regions that primarily mediate g5Rp-RNA interaction, elucidating the roles of InsP6 in the regulation of the viral decapping activity of g5Rp in mRNA degradation. Collectively, these results provide the structural basis of interaction between RNA and g5Rp and highlight the inhibitory mechanism of InsP6 on mRNA decapping by g5Rp.

biochemistry↗

bioRxiv2021

One viral sequence for each host? - The neglected within-host diversity as the main stage of SARS-CoV-2 evolution

The standard practice of presenting one viral sequence for each infected individual implicitly assumes low within-host genetic diversity. It places the emphasis on the viral evolution between, rather than within, hosts. To determine this diversity, we collect SARS-CoV-2 samples from the same patient multiple times. Our own data in conjunction with previous reports show that two viral samples collected from the same individual are often very different due to the substantial within-host diversity. Each sample captures only a small part of the total diversity that is transiently and locally released from infected cells. Hence, the global SARS-CoV-2 population is a meta-population consisting of the viruses in all the infected hosts, each of which harboring a genetically diverse sub-population. Advantageous mutations must be present first as the within-host diversity before they are revealed as between-host polymorphism. The early detection of such diversity in multiple hosts could be an alarm for potentially dangerous mutations. In conclusion, the main forces of viral evolution, i.e., mutation, drift, recombination and selection, all operate within hosts and should be studied accordingly. Several significant implications are discussed.

evolutionary biology↗

bioRxiv2021

A genotype independent DMP-HI system in dicot crops

Doubled haploid (DH) technology is used to obtain homozygous lines in a single generation, which significantly accelerates the crop breeding trajectory. Traditionally, in vitro culture is used to generate DHs, but is limited by species and genotype recalcitrance. In vivo haploid induction (HI) through seed is been widely and efficiently used in maize and was recently extended to several monocot crops. However, a similar generic and efficient HI system is still lacking in dicot crops. Here we show that genotype-independent in vivo HI can be triggered by mutation of DMP genes in tomato, rapeseed and tobacco with HI rates of ~1.9%, 2.4% and 1.2%, respectively. The DMP-HI system offers a robust DH technology to facilitate variety improvement in these crops. The success of this approach and the conservation of DMP genes paves the way for a generic and efficient genotype-independent HI system in other dicot crops.

plant biology↗

bioRxiv2021

Bacteriophage T4 Vaccine Platform for Next-generation Influenza Vaccine Development

Developing influenza vaccines that protect against a broad range of viruses is a public health priority, and several conserved viral proteins or domains have been identified as promising targets for such vaccine development. However, none of the targets is immunogenic, and vaccine platforms that can incorporate multiple antigens with enhanced immunogenicity are desperately needed. In this study, we provided proof-of-concept for the development of next-generation influenza vaccine using T4 phage virus-like particle (VLP) platform. With extracellular domain of influenza matrix protein 2 (M2e) as a readout, we showed that more than 1,280 M2e molecules can be assembled on a 120x90 nanometer phage capsid to form T4-M2e VLPs, which are highly immunogenic and induced complete protection against influenza virus challenge without any addition adjuvant. Potentially, additional conserved antigens or molecular adjuvants could be incorporated into the T4-M2e VLPs to customize influenza vaccines to address different issues. All the components of T4 VLP vaccines can be mass-produced in E. coli in a short time, therefore, providing a rapid approach to deal with the potential influenza pandemic.

microbiology↗

bioRxiv2021

Brain charts for the human lifespan

Over the past few decades, neuroimaging has become a ubiquitous tool in basic research and clinical studies of the human brain. However, no reference standards currently exist to quantify individual differences in neuroimaging metrics over time, in contrast to growth charts for anthropometric traits such as height and weight1. Here, we built an interactive resource to benchmark brain morphology, www.brainchart.io, derived from any current or future sample of magnetic resonance imaging (MRI) data. With the goal of basing these reference charts on the largest and most inclusive dataset available, we aggregated 123,984 MRI scans from 101,457 participants aged from 115 days post-conception through 100 postnatal years, across more than 100 primary research studies. Cerebrum tissue volumes and other global or regional MRI metrics were quantified by centile scores, relative to non-linear trajectories2 of brain structural changes, and rates of change, over the lifespan. Brain charts identified previously unreported neurodevelopmental milestones3; showed high stability of individual centile scores over longitudinal assessments; and demonstrated robustness to technical and methodological differences between primary studies. Centile scores showed increased heritability compared to non-centiled MRI phenotypes, and provided a standardised measure of atypical brain structure that revealed patterns of neuroanatomical variation across neurological and psychiatric disorders. In sum, brain charts are an essential first step towards robust quantification of individual deviations from normative trajectories in multiple, commonly-used neuroimaging phenotypes. Our collaborative study proves the principle that brain charts are achievable on a global scale over the entire lifespan, and applicable to analysis of diverse developmental and clinical effects on human brain structure. Furthermore, we provide open resources to support future advances towards adoption of brain charts as standards for quantitative benchmarking of typical or atypical brain MRI scans.

neuroscience↗

bioRxiv2021

BrainEXP-NPD: a database of transcriptomic profiles of human brains of six neuropsychiatric disorders

BackgroundSpatio-temporal gene expression has been widely used to study gene functions and biological mechanisms in diseases. Numerous microarray and RNA sequencing data focusing on brain transcriptomes in neuropsychiatric disorders have accumulated. However, their consistency, reproducibility has not been properly evaluated. Except for a few psychiatric disorders, like schizophrenia, bipolar disorder and autism, most have not been compared to each other for cross-disorder comparisons. MethodsWe organized 48 human brain transcriptome datasets from six sources. The original brain donors include patients with schizophrenia (SCZ, N=427), bipolar disorder (BD, N=312), major depressive disorder (MDD, N=219), autism spectrum disorder (ASD, N=53), Alzheimers disease (AD, N=765), Parkinsons disease (PD, N=163) as well as controls as unaffected by such disorders (CTRL, N=6,378), making it a total of 8,317 samples. Raw data included multiple brain regions of both sexes, with ages ranging from embryonic to seniors. After standardization, quality control, filtering and removal of known and unknown covariates, we performed comprehensive meta- and mega-analyses, including gene differential expression and gene co-expression network. ResultsA total of 6922, 3011, 2703, 4389, 3507, 4279 significantly differentially expressed genes (FDR q < 0.05) were detected in the comparisons of 6 brain regions of SCZ-CTRL, 5 brain regions of BD-CTRL, 6 brain regions of MDD-CTRL, 4 brain regions of ASD-CTRL, 7 brain regions of AD-CTRL, and 6 brain regions of PD-CTRL, respectively. Most differentially expressed genes were brain region-specific and disease-specific. SCZ and BD have a maximal transcriptome similarity in striatum ({rho}=0.42) among the four brain regions, as measured by Spearmans correlation of differential expression log2 FC values. SCZ and MDD have a maximal transcriptome similarity in hippocampus ({rho}=0.30) among the five brain regions. BD and MDD have a maximal transcriptome similarity in frontal cortex ({rho}=0.45) among the five brain regions. Other disease pairs have a less transcriptome similarity ({rho}<0.1) in all brain regions. PD is negatively correlated with SCZ, BD, and MDD in cerebellum and striatum. We also performed coexpression network analyses for different disorders and controls separately. We developed a database named BrainEXP-NPD (http://brainexpnpd.org:8088/BrainEXPNPD/), to provide a userfriendly web interface for accessing the data, and analytical results of meta- and mega-analyses, including gene differential expression and gene co-expression networks between cases and controls on different brain regions, sexes and age groups. Discussion: BrainEXP-NPD compiled the largest collection of brain transcriptomic data of major neuropsychiatric disorders and presented lists of differentially expressed genes and coexpression modules in multiple brain regions of six major disorders.

bioinformatics↗

bioRxiv2021

Unbiased screen of human transcriptome reveals an unexpected role of 3'UTRs in translation initiation

Although most eukaryotic mRNAs require a 5'-cap for translation initiation, some can also be translated through a poorly studied cap-independent pathway. Here we developed a circRNA-based system and unbiasedly identified more than 10,000 sequences in the human transcriptome that contain Cap-independent Translation Initiators (CiTIs). Surprisingly, most of the identified CiTIs are located in 3'UTRs, which mainly promote translation initiation in mRNAs bearing highly structured 5'UTR. Mechanistically, CiTI recruits several translation initiation factors including eIF3 and DHX29, which in turn unwind 5'UTR structures and facilitate ribosome scanning. Functionally, we showed that the translation of HIF1A mRNA, an endogenous DHX29 target, is antagonistically regulated by its 5'UTR structure and a new 3'-CiTI in response to hypoxia. Therefore, deletion of 3'-CiTI suppresses cell growth in hypoxia and tumor progression in vivo. Collectively, our study uncovers a new regulatory mode for translation where the 3'UTR actively participate in the translation initiation.

molecular biology↗

bioRxiv2021

Stabilization of the SARS-CoV-2 Spike receptor-binding domain using deep mutational scanning and structure-based design

The unprecedented global demand for SARS-CoV-2 vaccines has demonstrated the need for highly effective vaccine candidates that are thermostable and amenable to large-scale manufacturing. Nanoparticle immunogens presenting the receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein (S) in repetitive arrays are being advanced as second-generation vaccine candidates, as they feature robust manufacturing characteristics and have shown promising immunogenicity in preclinical models. Here, we used previously reported deep mutational scanning (DMS) data to guide the design of stabilized variants of the RBD. The selected mutations fill a cavity in the RBD that has been identified as a linoleic acid binding pocket. Screening of several designs led to the selection of two lead candidates that expressed at higher yields than the wild-type RBD. These stabilized RBDs possess enhanced thermal stability and resistance to aggregation, particularly when incorporated into an icosahedral nanoparticle immunogen that maintained its integrity and antigenicity for 28 days at 35-40{degrees}C, while corresponding immunogens displaying the wild-type RBD experienced aggregation and loss of antigenicity. The stabilized immunogens preserved the potent immunogenicity of the original nanoparticle immunogen, which is currently being evaluated in a Phase I/II clinical trial. Our findings may improve the scalability and stability of RBD-based coronavirus vaccines in any format and more generally highlight the utility of comprehensive DMS data in guiding vaccine design.

microbiology↗

bioRxiv2021

Injectable Progranulin-derivative Atsttrin loaded Protein Engineered Gels for Post Traumatic Osteoarthritis

Protein-based biomaterials offer several advantages over synthetic materials, owing to their unique stimuli-responsive properties, biocompatibility and modular nature. We have successfully developed protein block polymers that consist of elastin like polypeptide (E) and the coiled-coil domain of cartilage oligomeric matrix protein (C). Here, we demonstrate that E5C, a construct consisting of five repeats of E and a single domain of C, is capable of forming a porous networked gel at physiological temperature, making it an excellent candidate for injectable biomaterials. Combination of E5C with Atsttrin, a chondroprotective engineered derivative of anti-inflammatory growth factor progranulin (PGRN), provides a unique biochemical and biomechanical environment to protect against post-traumatic osteoarthritis (PTOA) onset and progression. E5C gel was demonstrated to provide prolonged release of Atsttrin and inhibit chondrocyte catabolism while facilitating anabolic signaling in vitro. We also provide in vivo evidence that prophylactic and therapeutic application of Atsttrin-loaded E5C hydrogels protected against PTOA onset and progression in a rabbit anterior cruciate ligament transection model. Collectively, we have developed a unique protein-based gel capable of minimally invasive, sustained delivery of prospective therapeutics, particularly the PGRN-derivative Atsttrin, for prevention of OA onset and progression.

bioengineering↗

bioRxiv2021

Spatiotemporal specificity of correlated DNA methylation and gene expression pairs across different human tissues and stages of brain development

DNA methylation (DNAm) that occurs on promoter regions is primarily considered to repress gene expression. Previous studies indicated that DNAm could also show positive correlations with gene expression. Both DNAm and gene expression profiles are known to be tissue- and development-specific. This study aims to investigate how DNAm and gene expression are coordinated across different human tissues and developmental stages, as well as the biological significance of such correlations. By analyzing 2,239 samples with both DNAm and gene expression data in the same human subjects obtained from six published datasets, we evaluated the correlations between gene and CpG pairs (GCPs) at cis-regions and compared significantly correlated GCPs (cGCPs) across different tissues and brains at different age groups. A total of 37,363 cGCPs were identified in the six datasets; approximately 38% of the cGCPs were positively correlated. The majority (>90%) of cGCPs were tissue- or development-specific. We also observed that the correlation direction can be opposite in different tissues and ages. Further analysis highlighted the importance of cGCPs for their cellular functions and potential roles in complex traits and human diseases. For instance, early developmental brain possessed a highly unique set of cGCPs that were associated with neurogenesis and psychiatric disorders. By assessing the epigenetic factors involved in cGCPs, we discovered novel regulatory mechanisms of positive cGCPs distinct from negative cGCPs, which were related to multiple factors, such as H3K27me3, CTCF, and JARD2. The catalog of cGCPs compiled can be used to guide functional interpretation of genetic and epigenetic studies.

genetics↗

bioRxiv2021

Mechanistic Insights of High Temperature-Interfered Meiosis in Autotetraploid Arabidopsis thaliana

Environmental temperature has a huge impact on multiple meiosis processes in flowering plants. Polyploid plants derived from whole genome duplication are believed to have an enhanced abiotic stress tolerance. In this study, the impact of high temperatures on male meiosis in autotetraploid Arabidopsis thaliana was investigated. We found that autotetraploid Columbia (Col-0) plants generate a subpopulation of aberrant meiotic products under normal temperature, which is significantly increased under heat stress. Cytological studies revealed that, as the case in diploid Arabidopsis thaliana, assembly of microtubular cytoskeleton network, pairing and segregation of homologous chromosomes, and meiotic recombination in autotetraploid Arabidopsis are compromised under the high temperatures. Immunostaining of {ramshorn}H2A.X and recombinase DMC1 suggested that heat stress inhibits formation of DNA double-strand breaks; additionally, it specifically destabilizes ASY1 and ASY4, but not SYN1 on chromosomes. The loading defects of ASY1 and ASY4 overlap in the syn1 mutant, which supports that the building of lateral element of synaptonemal complex occurs downstream of a SYN1-ASY4-ASY3 stepwise assembly of axis. Remarkably, heat-induced abnormalities of ASY1 and ASY4 co-localize on chromosomes of both diploid and autotetraploid Arabidopsis, suggesting that high temperatures interfere with ASY1-associated SC via an impacted stability of chromosome axis. Furthermore, ZYP1-dependent transverse filament of SC is disrupted by heat stress. Taken together, these findings suggest that polyploidization negatively contributes to instability of chromosome axis and meiotic recombination in Arabidopsis thaliana under heat stress.

plant biology↗

bioRxiv2021

Functional architecture of neural circuits for leg proprioception in Drosophila

To effectively control their bodies, animals rely on feedback from proprioceptive mechanosensory neurons. In the Drosophila leg, different proprioceptor subtypes monitor joint position, movement direction, and vibration. Here, we investigate how these diverse sensory signals are integrated by central proprioceptive circuits. We find that signals for leg joint position and directional movement converge in second-order neurons, revealing pathways for local feedback control of leg posture. Distinct populations of second-order neurons integrate tibia vibration signals across pairs of legs, suggesting a role in detecting external substrate vibration. In each pathway, the flow of sensory information is dynamically gated and sculpted by inhibition. Overall, our results reveal parallel pathways for processing of internal and external mechanosensory signals, which we propose mediate feedback control of leg movement and vibration sensing, respectively. The existence of a functional connectivity map also provides a resource for interpreting connectomic reconstruction of neural circuits for leg proprioception.

neuroscience↗