Biology subjects

Hu, Z.

Publications and source records attributed to Hu, Z..

At least 325 records · Page 18Linked to original sources

bioRxiv2019

Reconstructing species evolutionary trees using the numerical features of microRNA

Research has revealed that some microRNAs show obvious lineage or species specificity, but others show highly conserved properties among species. Based on these properties, we aimed to reconstruct a species evolution tree using a new technique that refers to the numerical features of microRNA. First, we selected 132 microRNA numerical features that included base content, secondary structure matching state frequency, free energy features and information entropy features, and 32 species that included 22 animals, 9 plants and a representative virus group. Second, we found several significantly different numerical features among lineages or species by statistical analysis and confirmed that differences in each numerical feature were not identical. Third, we designed a comprehensive feature and confirmed that it showed obvious lineage and species specificity. Last, species trees were built using the comprehensive feature. The results showed that the reconstructed species tree was almost in keeping with the actual chronological order of species evolution. This indicated that our analysis was effective. Our research strategy offers a new route for investigating species evolution.

bioinformatics↗

bioRxiv2019

Discovery Function Labels Based On Numerical Features Of MicroRNA Found In Plant

MicroRNAs(miRNAs),are a class of small endogenous non-coding RNAs that play Important post-transcriptional regulation role by degrading targeted mRNAs or repressing mRNA translation. We screened 84 miRNAs belonging to 21 conserved family from 4014 miRNAs in miRBase database which distributed in 47 plant species. Of the predicted 274 target genes,42 GO terms were found in the Gene Ontology. With the 135 numerical features which extracted by perl program, the difference significantly result of ANOVA (P<0.001) and multiple comparison show that the function labels G...,GC content and Helix in biological process, cellular component and biological function, respectively. Our result have suggested a potential connection between numerical features of miRNAs and the function of target genes of miRNAs.

bioinformatics↗

bioRxiv2019

A new strategy for selection of crop cultivated varieties based on yield factors driving and meteorological prediction

Meteorological conditions, as an uncontrollable factor, have a direct impact on the growth and yield of crops in the field. Its particularly important to choose the cultivated varieties suitable for environmental change. As for this problem, a new strategy for selection of crop cultivated varieties is proposed in this paper. The experiment selected Harbin pilot (Heilongjiang, China) and Changchun pilot (Jilin, China). In the experiment, the cultivated varieties suitable for forecasting meteorological conditions in 2015 could be provided according to the meteorological data of 2005-2014 years and the yield data of different soybean varieties in Harbin pilot. The same method was also taken in Changchun pilot. The results showed that the recommended varieties of Harbin pilot and Changchun pilot had 70% and 50% probability respectively for selection of soybean cultivated varieties when the yield evaluation trait was 100-seed-weight. As for seed weight per plant, the possibility of more than 60% of the recommended varieties in two pilots is to provide prejudgment. Therefore, this method can help to improve the current situation of the impact of uncontrollable meteorological conditions on crop yield and also can be applied to the selection of any other crops cultivated varieties under a certain environment.

plant biology↗

bioRxiv2019

Dissecting adaptive traits with nested association mapping: Genetic architecture of inflorescence morphology in sorghum

In the cereal crop sorghum (Sorghum bicolor) inflorescence morphology variation underlies yield variation and confers adaptation across precipitation gradients, but its genetic basis is poorly understood. Here we characterized the genetic architecture of sorghum inflorescence morphology using a global nested association mapping (NAM) population (2200 recombinant inbred lines) and 198,000 phenotypic observations from multi-environment trials for four inflorescence morphology traits (upper branch length, lower branch length, rachis length, and rachis diameter). Trait correlations suggest that lower and upper branch length are under largely independent genetic control, while lower branch length and rachis diameter are pleiotropic. Joint linkage and genome-wide association mapping revealed an oligogenic architecture with 1-22 QTL per trait, each explaining 0.1%-5.0% of variation across the entire NAM population. Overall, there is a significant enrichment (2.4-fold) of QTL colocalizing with homologs of grass inflorescence genes, notably with orthologs of maize (Ramosa2) and rice (Aberrant Panicle Organization1, TAWAWA1) inflorescence regulators. In global georeferenced germplasm, allelic variation at the major inflorescence morphology QTL is significantly associated with precipitation gradients, consistent with a role for these QTL in adaptation to agroclimatic zones. The findings suggest that global inflorescence diversity in sorghum is largely controlled by oligogenic, epistatic, and pleiotropic variation in ancestral regulatory networks. This genotype-phenotype trait dissection in global germplasm provides a basis for genomics-enabled breeding of locally-adapted inflorescence morphology.

genetics↗

bioRxiv2019

Bone-targeted lncRNA OGRU alleviates unloading-induced bone loss via miR-320-3p/Hoxa10 axis

Although the underlying molecular mechanism of unloading-induced bone loss has been broadly elucidated, the pathophysiological role of long noncoding RNAs (lncRNAs) in this process is unknown. Here, we identified a novel lncRNA, OGRU, a 1816-nucleotide transcript with significantly decreased levels in bone specimens from hindlimb-unloaded mice and in MC3T3-E1 cells under clinorotation unloading conditions. OGRU overexpression promoted osteoblast activity and matrix mineralization under normal loading conditions and attenuated the suppression of MC3T3-E1 cell differentiation induced by clinorotation unloading. Furthermore, this study found that supplementation of pcDNA3.1(+)-OGRU via (DSS)6-liposome delivery to the bone formation surfaces of hindlimb-unloaded (HLU) mice partially alleviated unloading-induced bone loss. Mechanistic investigations demonstrated that OGRU can function as a competing endogenous RNA (ceRNA) to facilitate the protein expression of Hoxa10 by competitively binding miR-320-3p and subsequently promote osteoblast differentiation and bone formation. Taken together, the results of our study provide the first clarification of the role of the OGRU in unloading-induced bone loss through the miR-320-3p/Hoxa10 axis, suggesting an efficient anabolic strategy for osteoporosis treatment.

molecular biology↗

bioRxiv2019

Cyclin Dependent Kinase 5 (CDK5) Regulates the Circadian Clock

Circadian oscillations emerge from transcriptional and post-translational feedback loops. An important step in generating rhythmicity is the translocation of clock components into the nucleus, which is regulated in many cases by kinases. In mammals, the kinase promoting the nuclear import of the key clock component Period 2 (PER2) is unknown. Here we show that the cyclin-dependent kinase 5 (CDK5) regulates the mammalian circadian clock involving phosphorylation of PER2. Knock-down of Cdk5 in the suprachiasmatic nuclei (SCN), the main coordinator site of the mammalian circadian system, shortened the free-running period in mice. CDK5 phosphorylated PER2 at serine residue 394 (S394) in a diurnal fashion. This phosphorylation facilitated interaction with Cryptochrome 1 (CRY1) and nuclear entry of the PER2-CRY1 complex. Taken together, we found that CDK5 drives nuclear entry of PER2, which is critical for establishing an adequate circadian period of the molecular circadian cycle. Therefore, CDK5 is critically involved in the regulation of the circadian clock and may represent a link to various diseases affected by the circadian clock.

neuroscience↗

bioRxiv2019

The repertoire of serous ovarian cancer non-genetic heterogeneity revealed by single-cell sequencing of normal fallopian tube epithelial cells

The inter-differentiation between cell states promotes cancer cell survival under stress and fosters non-genetic heterogeneity (NGH). NGH is, therefore, a surrogate of tumor resilience but its quantification is confounded by genetic heterogeneity. Here we show that NGH can be accurately measured when informed by the molecular signatures of the normal cells of origin. We surveyed the transcriptomes of [~] 4000 normal fallopian tube epithelial (FTE) cells, the cells of origin of serous ovarian cancer (SOC), and identified six FTE subtypes. We used subtype signatures to deconvolute SOC expression data and found substantial intra-tumor NGH that was previously unrecognized. Importantly, NGH-based stratification of [~]1700 tumors robustly predicted survival. Our findings lay the foundation for accurate prognostic and therapeutic stratification of SOC.\n\nHighlightsO_LIThe projection of FTE subtypes refines the molecular classification of serous OC\nC_LIO_LIComprehensive single-cell profiling of FTE cells identifies 6 molecular subtypes\nC_LIO_LISubstantial non-genetic heterogeneity of HGSOC identified in 1700 tumors\nC_LIO_LIA mesenchymal-high HGSOC subtype is robustly correlated with poor prognosis\nC_LI

cancer biology↗

bioRxiv2019

Diverse noncanonical PAMs recognized by SpCas9 in human cells

The CRISPR/Cas9 system derived from Streptococcus pyogenes (SpCas9) provides unprecedented genome editing capabilities, but the potential for off-target mutations limits its application. In addition to NGG protospacer adjacent motif (PAM), off-target mutations are also associated with noncanonical PAMs, which have not yet been systematically evaluated. Here, we developed a highly sensitive approach that allows systematically analyzing PAM sequences in human cells, and identified multiple alternative PAMs recognized by SpCas9.

bioengineering↗

bioRxiv2019

First report on the effective intraperitoneal therapy of insulin-dependent diabetes mellitus in pet dogs using \"Neo-Islets\", aggregates of adipose stem and pancreatic islet cells

We previously reported that allogeneic, intraperitoneally administered \"Neo-Islets,\" composed of cultured pancreatic islet cells co-aggregated with high numbers of immunoprotective and cytoprotective Adipose-derived Stem Cells, reestablished, through omental engraftment, redifferentiation and splenic and omental up-regulation of Regulatory T-cells, normoglycemia in autoimmune Type-1 Diabetic Non-Obese Diabetic (NOD) mice without the use of immunosuppressive agents or encapsulation devices. Based on these observations, we are currently testing this Neo-Islet technology in an FDA guided Pilot Study (INAD 012-776) in insulin-dependent, spontaneously diabetic pet dogs by the intraperitoneal administration of 2x10e5 Neo-Islets/kilogram body weight to metabolically controlled (blood glucose, triglycerides, thyroid and adrenal functions) animals under sedation and local anesthesia and ultrasound guidance. We report here initial observations on the first 4 Neo-Islet-treated, insulin dependent pet dogs that are now in the intermediate-term follow-up phase of the study (> 6 months post treatment). Current results indicate that in dogs, Neo-Islets appear to engraft, redifferentiate and physiologically produce insulin, and are neither rejected by auto- or allo-immune attacks, as evidenced by (a) an absent IgG response to the allogeneic cells contained in the administered Neo-Islets, and (b) progressively improved glycemic control that achieves up to a 50% reduction in daily insulin needs paralleled by a significant fall in serum glucose levels. This is accomplished without the use of anti-rejection drugs or encapsulation devices. No adverse or serious adverse events related to the Neo-Islet administration have been observed to date. We conclude that this minimally invasive therapy has significant translational relevance to veterinary and clinical Type 1 Diabetes Mellitus by achieving complete and at this point partial glycemic control in two species, i.e., diabetic mice and dogs, respectively.

cell biology↗

bioRxiv2019

A web-server framework to explore and visualize large genomic variation data in lab and its applications to wheat and its progenitors

BackgroundThe cost of high-throughput sequencing is rapidly decreasing, allowing researchers to investigate genomic variations across hundreds or even thousands of samples in the post-genomic era. The management and exploration of these large-scale genomic variation data require programming skills. The public genotype querying databases of many species are usually centralized and implemented independently, making them difficult to update with new data over time. Currently, there is a lack of a widely used framework for setting up user-friendly web servers for exploring new genomic variation data in diverse species. ResultsHere, we present SnpHub, a Shiny/R-based server framework for retrieving, analysing and visualizing the large-scale genomic variation data that be easily set up on any Linux server. After a pre-building process based on the provided VCF files and genome annotation files, the local server allows users to interactively access SNPs/INDELs and annotation information by locus or gene and for user-defined sample sets through a webpage. Users can freely analyse and visualize genomic variations in heatmaps, phylogenetic trees, haplotype networks, or geographical maps. Sample-specific sequences can be accessed as replaced by SNPs/INDELs. ConclusionsSnpHub can be applied to any species, and we build up a SnpHub portal website for wheat and its progenitors based on published data in present studies. SnpHub and its tutorial are available as http://guoweilong.github.io/SnpHub/.

bioinformatics↗

bioRxiv2019

Genomics of sorghum local adaptation to a parasitic plant

Host-parasite coevolution can maintain high levels of genetic diversity in traits involved in species interactions. In many systems, host traits exploited by parasites are constrained by use in other functions, leading to complex selective pressures across space and time. Here, we study genome-wide variation in the staple crop Sorghum bicolor (L.) Moench and its association with the parasitic weed Striga hermonthica (Delile) Benth., a major constraint to food security in Africa. We hypothesize that geographic selection mosaics across gradients of parasite occurrence maintain genetic diversity in sorghum landrace resistance. Suggesting a role in local adaptation to parasite pressure, multiple independent loss-of-function alleles at sorghum LOW GERMINATION STIMULANT 1 (LGS1) are broadly distributed among African landraces and geographically associated with S. hermonthica occurrence. However, low frequency of these alleles within S. hermonthica-prone regions and their absence elsewhere implicate potential tradeoffs restricting their fixation. LGS1 is thought to cause resistance by changing stereochemistry of strigolactones, hormones that control plant architecture and belowground signaling to mycorrhizae and are required to stimulate parasite germination. Consistent with tradeoffs, we find signatures of balancing selection surrounding LGS1 and other candidates from analysis of genome-wide associations with parasite distribution. Experiments with CRISPR-Cas9 edited sorghum further indicate the benefit of LGS1-mediated resistance strongly depends on parasite genotype and abiotic environment and comes at the cost of reduced photosystem gene expression. Our study demonstrates long-term maintenance of diversity in host resistance genes across smallholder agroecosystems, providing a valuable comparison to both industrial farming systems and natural communities. SIGNIFICANCE STATEMENTUnderstanding co-evolution in crop-parasite systems is critical to management of myriad pests and pathogens confronting modern agriculture. In contrast to wild plant communities, parasites in agricultural ecosystems are usually expected to gain the upper hand in co-evolutionary arms races due to limited genetic diversity of host crops in cultivation. Here, we develop a framework to characterize associations between genome variants in global landraces (traditional varieties) of the staple crop sorghum with the distribution of the devastating parasitic weed Striga hermonthica. We find long-term maintenance of diversity in genes related to parasite resistance, highlighting an important role of host adaptation for co-evolutionary dynamics in smallholder agroecosystems.

evolutionary biology↗

bioRxiv2019

Genetic Architecture of Chilling Tolerance in Sorghum Dissected with a Nested Association Mapping Population

Dissecting the genetic architecture of stress tolerance in crops is critical to understand and improve adaptation. In temperate climates, early planting of chilling-tolerant varieties could provide longer growing seasons and drought escape, but chilling tolerance (<15{degrees}) is generally lacking in tropical-origin crops. Here we developed a nested association mapping (NAM) population to dissect the genetic architecture of early-season chilling tolerance in the tropical-origin cereal sorghum (Sorghum bicolor [L.] Moench). The NAM resource, developed from reference line BTx623 and three chilling-tolerant Chinese lines, is comprised of 771 recombinant inbred lines genotyped by sequencing at 43,320 single nucleotide polymorphisms. We phenotyped the NAM population for emergence, seedling vigor, and agronomic traits (>75,000 data points from [~]16,000 plots) in multi-environment field trials in Kansas under natural chilling stress (sown 30-45 days early) and normal growing conditions. Joint linkage mapping with early-planted field phenotypes revealed an oligogenic architecture, with 5-10 chilling tolerance loci explaining 20-41% of variation. Surprisingly, several of the major chilling tolerance loci co-localize precisely with the classical grain tannin (Tan1 and Tan2) and dwarfing genes (Dw1 and Dw3) that were under strong directional selection in the US during the 20th century. These findings suggest that chilling sensitivity was inadvertently selected due to coinheritance with desired nontannin and dwarfing alleles. The characterization of genetic architecture with NAM reveals why past chilling tolerance breeding was stymied and provides a path for genomics-enabled breeding of chilling tolerance.\n\nArticle SummaryChilling sensitivity limits productivity of tropical-origin crops in temperate climates, and remains poorly understood at a genetic level. We developed a nested association mapping resource in sorghum, a tropical-origin cereal, to understand the genetic architecture of chilling tolerance. Linkage mapping of growth traits from early-planted field trials revealed several major chilling tolerance loci, including some colocalized with genes that were selected in the origin of US grain sorghum. These findings suggest chilling sensitivity was inadvertently selected during 20th century breeding, but can be bypassed using a better understanding of the underlying genetic architecture.\n\nDisclaimerMention of a trademark, warranty, proprietary product, or vendor does not constitute a guarantee by the USDA and does not imply approval or recommendation of the product to the exclusion of others that may be suitable. USDA is an equal opportunity provider and employer.

genetics↗

bioRxiv2019

Meiosis related cancer-testis genes correlate with tumor aneuploidy and immune infiltration in 21 cancer types

The meiosis stage of spermatogenesis and the aneuploidy generation in tumorigenesis are highly linked. Cancer-testis genes (CT genes) were specifically expressed in testis and cancers and may serve as the molecular basis of the shared features between spermatogenesis and tumorigenesis. In the present study, we integrated multi-omics data from bulk samples and cell lines, and single cell RNA-Seq data from testis and two tumors to systematically investigate the association between CT genes and aneuploidy. After ranking genes according to their association with aneuploidy level, we found that CT genes, especially CT genes specifically expressed in meiosis, showed a consistently positive correlation with aneuploidy and homologous recombination deficiency (HRD) level. Similar results were also found in the CT non-coding genes. Then, we constructed a regulatory network based on the single cell RNA-seq data and revealed that the gain of accelerator transcriptional factors (TFs) E2F7 and E2F8 and the loss of the stabilizer TFs RFX2 and NFYA aberrantly activated CT genes in the cancers and were associated with the increase of HRD level. Finally, we found that the association between CT genes and cytotoxic infiltrating lymphocytes can be influenced by the HRD level. In sum, our results revealed the evidence of pseudomeiotic functions of CT genes in the aneuploidy generation process in the cancer cells. The results may help illuminate the origin of aneuploidy in cancers and guide future immunotherapy targeting CT antigens.

genomics↗

bioRxiv2019

Disruption of the kringle 1 domain of prothrombin leads to late onset mortality in zebrafish

The ability to prevent blood loss in response to injury is a critical, evolutionarily conserved function of all vertebrates. Prothrombin (F2) contributes to both primary and secondary hemostasis through the activation of platelets and the conversion of soluble fibrinogen to insoluble fibrin, respectively. Complete prothrombin deficiency has never been observed in humans and is incompatible with life in mice, limiting the ability to understand the entirety of prothrombins in vivo functions. We have previously demonstrated the ability of zebrafish to tolerate loss of both pro- and anticoagulant factors that are embryonic lethal in mammals, making them an ideal model for the study of prothrombin deficiency. Using genome editing with TALENs, we have generated a null allele in zebrafish f2. Homozygous mutant embryos develop normally into early adulthood, but demonstrate eventual complete mortality with the majority of fish succumbing to internal hemorrhage by 2 months of age. We show that despite the extended survival, the mutants are unable to form occlusive thrombi in both the venous and arterial systems as early as 3-5 days of life, and we were able to phenocopy this early hemostatic defect using direct oral anticoagulants. When the equivalent mutation was engineered into the homologous residues of human prothrombin, there were severe reductions in secretion and activation, suggesting a possible role for kringle 1 in thrombin maturation, and the possibility that the F1.2 fragment has a functional role in exerting the procoagulant effects of thrombin. Together, our data demonstrate the conserved function of thrombin in zebrafish, as well as the requirement for kringle 1 for biosynthesis and activation by prothrombinase. Understanding how zebrafish are able to develop normally and survive into early adulthood without prothrombin will provide important insight into its pleiotropic functions as well as the management of patients with bleeding disorders.\n\nKey PointsO_LIDisruption of the kringle 1 domain of prothrombin leads to severe impairment of biosynthesis, activation, and activity\nC_LIO_LIProthrombin deficiency is compatible with normal development in zebrafish but leads to inability to form clots followed by early mortality\nC_LI

genetics↗

bioRxiv2019

Epistasis detection and modeling for genomic selection in cowpea (Vigna unguiculata. L. Walp.)

Genetic architecture reflects the pattern of effects and interaction of genes underling phenotypic variation. Most mapping and breeding approaches generally consider the additive part of variation but offer limited knowledge on the benefits of epistasis which explains in part the variation observed in traits. In this study, the cowpea multiparent advanced generation inter-cross (MAGIC) population was used to characterize the epistatic genetic architecture of flowering time, maturity, and seed size. In addition, considerations for epistatic genetic architecture in genomic-enabled breeding (GEB) was investigated using parametric, semi-parametric, and non-parametric genomic selection (GS) models. Our results showed that large and moderate effect sized two-way epistatic interactions underlie the traits examined. Flowering time QTL colocalized with cowpea putative orthologs of Arabidopsis thaliana and Glycine max genes like PHYTOCLOCK1 (PCL1 [Vigun11g157600]) and PHYTOCHROME A (PHY A [Vigun01g205500]). Flowering time adaptation to long and short photoperiod was found to be controlled by distinct and common main and epistatic loci. Parametric and semi-parametric GS models outperformed non-parametric GS model. Using known QTL as fixed effects in GS models improved prediction accuracy when traits were controlled by both large and moderate effect QTL. In general, our study demonstrated that prior understanding the genetic architecture of a trait can help make informed decisions in GEB. This is the first report to characterize epistasis and provide insights into the underpinnings of GS versus marker assisted selection in cowpea.

genetics↗

bioRxiv2018

Sonodynamic therapy as an adjunctivw treatment on porphyromonas gingivalis induced periodontitis in rats with diabetes

ObjectivesThe purpose of our research was to examine the effects of Minocycline combined hyaluronic acid (HA)-mediated Ultrasound therapy of infected wound in wister rats.\n\nMethods40 female wister rats were made wound on the two side of the backbone, then infected in Staphylococcus aureus at the comic for three times. then, they are divided into four groups: control group, minocycline combined HA alone, ultasound alone, minocycline combined HA-mediated ultasound group, respective. After 3 times of treatments, the rats were killed and made into specimens. Assessments consisted of visual inspection in the change of the skin, scar formation pathological morphology by hematoxylin and eosin(HE) stain with optical microscopy, IL-1B assaying and TNF-a were performed.\n\nResultCompared with control group, minocycline combined HA alone, ultasound alone, minocycline combined HA-mediated ultasound group all have effect for wound healing, there was a obvious improvement in all parameters over the duration of the experiment(P<0.05). Compared with the control group, minocycline combined HA-mediated ultasound group indicated less inflammation cells (P<0.001) and the reduce of and IL-1B and TNF-a (P<0.001).\n\nConclusionMinocycline combined HA-mediated ultrasound can accelerate tissue regrowth, which exert significant benefits in healing the wounds.

microbiology↗

bioRxiv2018

Construction and Characterization of a Synthetic Baculovirus-inducible 39K Promoter

The low expression activity and specificity of natural promoters limit the applications of genetic engineering. To construct a highly efficient synthetic inducible promoter in the Bombyx mori (Lepidoptera), we analyzed the regulatory elements and functional regions of the B. mori nucleopolyhedrovirus (BmNPV) 39K promoter. The results of truncated mutation analysis of the 39K promoter showed that the transcriptional regulatory region spanning positions -573 to -274 and +1 to +62 is essential for virus-inducible promoter activity. Further investigation using electrophoretic mobility shift assay (EMSA) revealed that the baculovirus IE-1 protein binds to the 39K promoter at the -310 to -355 region, and transcription activates the expression of 39K promoter assay. Finally, we successfully constructed a synthetic inducible promoter that increase the virus-inducing activity of other promoters using the baculovirus-inducible transcriptional activation region that binds to specific core elements of 39K (i.e., spanning the region -310 to -355). In summary, we describes a novel, synthetic, and highly efficient biological tool, namely, a virus-inducible 39K promoter, which provides endless possibilities for future gene function research, gene therapy, and pest control in genetic engineering.

bioengineering↗

bioRxiv2018

Heterodimerization of UNC-13/RIM regulates synaptic vesicle release probability but not priming

UNC-13 proteins play an essential role in synaptic transmission by recruiting synaptic vesicles (SVs) to become available for release, which is termed SV priming. Here we show that the C2A domain of UNC-13L, like the corresponding domain in mammalian Munc13-1, displays two conserved binding modes: forming C2A/C2A homodimers, or forming a heterodimer with the zinc finger domain of UNC-10/RIM (C2A/RIM). Functional analysis revealed that UNC-13Ls C2A promotes synaptic transmission by regulating a post-priming process. Stimulus-evoked release but not SV priming, was impaired in unc-10 mutants deficient for C2A/RIM heterodimerization, leading to decreased release probability. Disrupting C2A/C2A homodimerization in UNC-13L-rescued animals had no effect on synaptic transmission, but fully restored the evoked release and the release probability of unc-10/RIM mutants deficient for C2A/RIM heterodimerization. Thus, our results support the model that RIM binding C2A releases UNC-13L from an autoinhibitory homodimeric complex to become fusion-competent by functioning as a switch only.

neuroscience↗