Biology subjects

Jiang, L.

Publications and source records attributed to Jiang, L..

At least 271 records · Page 15Linked to original sources

bioRxiv2019

Quantifying genetic heterogeneity between continental populations for human height and body mass index

Genome-wide association studies (GWAS) in samples of European ancestry have identified thousands of genetic variants associated with complex traits in humans. However, it remains largely unclear whether these associations can be used in non-European populations. Here, we seek to quantify the proportion of genetic variation for a complex trait shared between continental populations. We estimated the between-population correlation of genetic effects at all SNPs (rg) or genome-wide significant SNPs (rg(GWS)) for height and body mass index (BMI) in samples of European (EUR; n = 49,839) and African (AFR; n = 17,426) ancestry. The [Formula] between EUR and AFR was 0.75 (s. e. = 0.035) for height and 0.68 (s. e. = 0.062) for BMI, and the corresponding [Formula] was 0.82 (s. e. = 0.030) for height and 0.87 (s. e. = 0.064) for BMI, suggesting that a large proportion of GWAS findings discovered in Europeans are likely applicable to non-Europeans for height and BMI. There was no evidence that [Formula] differs in SNP groups with different levels of between-population difference in allele frequency or linkage disequilibrium, which, however, can be due to the lack of power.

genetics↗

bioRxiv2019

A genome-wide almanac of co-essential modules assigns function to uncharacterized genes

A central remaining question in the post-genomic era is how genes interact to form biological pathways. Measurements of gene dependency across hundreds of cell lines have been used to cluster genes into co-essential pathways, but this approach has been limited by ubiquitous false positives. Here, we develop a statistical method that enables robust identification of gene co-essentiality and yields a genome-wide set of functional modules. This almanac recapitulates diverse pathways and protein complexes and predicts the functions of 102 uncharacterized genes. Validating top predictions, we show that TMEM189 encodes plasmanylethanolamine desaturase, the long-sought key enzyme for plasmalogen synthesis. We also show that C15orf57 binds the AP2 complex, localizes to clathrin-coated pits, and enables efficient transferrin uptake. Finally, we provide an interactive web tool for the community to explore the results (coessentiality.net). Our results establish co-essentiality profiling as a powerful resource for biological pathway identification and discovery of novel gene functions.

genomics↗

bioRxiv2019

One-step generation of zebrafish carrying a conditional knockout-knockin visible switch via CRISPR/Cas9-mediated intron targeting

The zebrafish has been becoming a popular vertebrate animal model in biomedical research. However, it is still challenging for making conditional gene knockout (CKO) zebrafish due to the low efficiency of homologous recombination (HR). Here we report an efficient non-HR-based method for generating zebrafish carrying a CKO and knockin (KI) switch (zCKOIS) coupled with dual-color fluorescent reporters. Using this strategy, we generated hey2zCKOIS which served as a hey2 KI reporter with EGFP expression. Upon Cre induction in targeted cells, the hey2zCKOIS was switched to a non-functional CKO allele hey2zCKOIS-inv associated with TagRFP expression, enabling to visualize CKO alleles. Thus, the simplification of the design, and the visibility and combination of both CKO and KI alleles engineering make our zCKOIS strategy an applicable CKO approach for zebrafish.

genetics↗

bioRxiv2019

Mechanistic insights into NAD synthase NMNAT chaperoning phosphorylated Tau from pathological aggregation

Tau hyper-phosphorylation and deposition into neurofibrillary tangles have been found in brains of patients with Alzheimers disease (AD) and other tauopathies. Molecular chaperones are involved in regulating the pathological aggregation of phosphorylated Tau (pTau) and modulating disease progression. Here, we report that nicotinamide mononucleotide adenylyltransferase (NMNAT), a well-known NAD synthase, serves as a chaperone of pTau to prevent its amyloid aggregation in vitro as well as mitigate its pathology in a fly tauopathy model. By combining NMR spectroscopy, crystallography, single-molecule and computational approaches, we revealed that NMNAT adopts its enzymatic pocket to specifically bind the phosphorylated sites of pTau, which can be competitively disrupted by the enzymatic substrates of NMNAT. Moreover, we found that NMNAT serves as a co-chaperone of Hsp90 for the specific recognition of pTau over Tau. Our work uncovers a dedicated chaperone of pTau and suggests NMNAT as a key node between NAD metabolism and Tau homeostasis in aging and neurodegeneration.

biochemistry↗

bioRxiv2019

A Quantitative Proteome Map of the Human Body

Determining protein levels in each tissue and how they compare with RNA levels is important for understanding human biology and disease as well as regulatory processes that control protein levels. We quantified the relative protein levels from 12,627 genes across 32 normal human tissue types prepared by the GTEx project. Known and new tissue specific or enriched proteins (5,499) were identified and compared to transcriptome data. Many ubiquitous transcripts are found to encode highly tissue specific proteins. Discordance in the sites of RNA expression and protein detection also revealed potential sites of synthesis and action of protein signaling molecules. Overall, these results provide an extraordinary resource, and demonstrate that understanding protein levels can provide insights into metabolism, regulation, secretome, and human diseases.\n\nSummaryQuantitative proteome study of 32 human tissues and integrated analysis with transcriptome data revealed that understanding protein levels could provide in-depth knowledge to post transcriptional or translational regulations, human metabolism, secretome, and diseases.

systems biology↗

bioRxiv2019

RobNorm: Model-Based Robust Normalization for High-Throughput Proteomics from Mass Spectrometry Platform

MotivationData normalization is an important step in processing proteomics data generated in mass spectrometry (MS) experiments, which aims to reduce sample-level variation and facilitate comparisons of samples. Previously published methods for normalization primarily depend on the assumption that the distribution of protein expression is similar across all samples. However, this assumption fails when the protein expression data is generated from heterogenous samples, such as from various tissue types. This led us to develop a novel data-driven method for improved normalization to correct the systematic bias meanwhile maintaining underlying biological heterogeneity. MethodsTo robustly correct the systematic bias, we used the density-power-weight method to down-weigh outliers and extended the one-dimensional robust fitting method described in the previous work of (Windham, 1995, Fujisawa and Eguchi, 2008) to our structured data. We then constructed a robustness criterion and developed a new normalization algorithm, called RobNorm. ResultsIn simulation studies and analysis of real data from the genotype-tissue expression (GTEx) project, we compared and evaluated the performance of RobNorm against other normalization methods. We found that the RobNorm approach exhibits the greatest reduction in systematic bias while maintaining across-tissue variation, especially for datasets from highly heterogeneous samples. Availabilityhttps://github.com/mwgrassgreen/RobNorm Contacthuatang@stanford.edu and mpsnyder@stanford.edu

bioinformatics↗

bioRxiv2019

Tuber yield and processing quality response of French fried potatoes to nitrogen fertilization

Nitrogen (N) is an important factor that influences potato production; appropriate N fertilizer management can optimize tuber yield and quality and thus reduce the risk of environmental N losses. The present study aimed to evaluate the effects of different nitrogen (N) application rates (0, 75, 150, 225, 300, and 375 kg ha-1) on the total tuber yield, marketable yield, dry matter content, reducing sugar content, sucrose content of tuber, and fry color index of two potato cultivars (Kennebec and Shepody) in 2016 and 2017. N supply significantly affected tuber yield and processing quality, but these effects depended on the year and/or cultivar. The results indicated that low (75 kg ha-1) and medium-N application rates (150 or 225 kg ha-1) had a positive effect on tuber yield and processing quality; however, high-N application rates (300 and 375 kg ha-1) resulted in lower yield and poor quality. Total and marketable yields responded quadratically to N, and they were optimized at 150 kg ha -1 for Kennebec and 225 kg ha-1 for Shepody in both the years. The processing quality of tubers also responded quadratically with increasing N application rates. The optimal range of N application was approximately 145-185.83 kg ha-1 for Kennebec and approximately 93.44-288.67 kg ha-1 for Shepody according to the processing quality standards of French fried potatoes in China. To achieve the goals of high yield and high quality, N application rates should be 150 kg ha-1for Kennebec and 225 kg ha-1 for Shepody.

plant biology↗

bioRxiv2019

Bayesian analysis of GWAS summary data reveals differential signatures of natural selection across human complex traits and functional genomic categories

Understanding how natural selection has shaped the genetic architecture of complex traits and diseases is of importance in medical and evolutionary genetics. Bayesian methods have been developed using individual-level data to estimate multiple features of genetic architecture, including signatures of natural selection. Here, we present an enhanced method (SBayesS) that only requires GWAS summary statistics and incorporates functional genomic annotations. We analysed GWAS data with large sample sizes for 155 complex traits and detected pervasive signatures of negative selection with diverse estimates of SNP-based heritability and polygenicity. Projecting these estimates onto a map of genetic architecture obtained from evolutionary simulations revealed relatively strong natural selection on genetic variants associated with cardiorespiratory and cognitive traits and relatively small number of mutational targets for diseases. Averaging across traits, the joint distribution of SNP effect size and MAF varied across functional genomic regions (likely to be a consequence of natural selection), with enrichment in both the number of associated variants and the magnitude of effect sizes in regions such as transcriptional start sites, coding regions and 5- and 3-UTRs.

genetics↗

bioRxiv2019

Cryo-EM structures of alpha-synuclein fibrils with the H50Q hereditary mutation reveal new polymorphs

Abstract\n\nDeposits of amyloid fibrils of -synuclein are the histological hallmarks of Parkinsons disease, multiple system atrophy, and dementia with Lewy bodies. Although most cases of these diseases are sporadic, autosomal-dominant hereditary mutations have been linked to Parkinsons disease and dementia with Lewy bodies. Seeing the changes to the structure of amyloid fibrils bearing these mutations may help to understand these diseases. To this end, we determined the cryo-EM structures of -synuclein fibrils containing the H50Q hereditary mutation. We find that the H50Q mutation results in two new polymorphs of -synuclein, which we term Narrow and Wide Fibrils. Both polymorphs recapitulate the conserved kernel formed by residues 50-77 observed in wild-type structures; however, the Narrow and Wide Fibrils reveal that H50Q disrupts a key interaction between H50-E57 on the opposing protofilament, abolishing the extensive protofilament interface formed by preNAC residues in the wild-type \"rod\" structure. Instead, the Narrow Fibril is formed from a single protofilament and the two protofilaments of the Wide protofilament are held together by only a pair of atoms - the C{gamma} atoms from the two threonine 59 sidechains. Further, we find that H50Q forms an intramolecular hydrogen bond with K45 leading to the formation of a novel {beta}-arch formed by residues 36-46 that features an extensive hydrogen-bond network between Y39, T44, and E46. The structures of the H50Q polymorphs help to rationalize the faster aggregation kinetics, higher seeding capacity in biosensor cells, and greater cytotoxicity we observe for H50Q compared to wild-type -synuclein.

biochemistry↗

bioRxiv2019

Models of heterogeneous dopamine signaling in an insect learning and memory center

The Drosophila mushroom body exhibits dopamine dependent synaptic plasticity that underlies the acquisition of associative memories. Recordings of dopamine neurons in this system have identified signals related to external reinforcement such as reward and punishment. However, other factors including locomotion, novelty, reward expectation, and internal state have also recently been shown to modulate dopamine neurons. This heterogeneity is at odds with typical modeling approaches in which these neurons are assumed to encode a global, scalar error signal. How is dopamine dependent plasticity coordinated in the presence of such heterogeneity? We develop a modeling approach that infers a pattern of dopamine activity sufficient to solve defined behavioral tasks, given architectural constraints informed by knowledge of mushroom body circuitry. Model dopamine neurons exhibit diverse tuning to task parameters while nonetheless producing coherent learned behaviors. Our results provide a mechanistic framework that accounts for the heterogeneity of dopamine activity during learning and behavior.

neuroscience↗

bioRxiv2019

Noninvasive Prenatal Diagnosis for Duchenne Muscular Dystrophy Based on the Direct Haplotype Phasing

ObjectiveWe aimed to investigate the validity of noninvasive prenatal diagnosis (NIPD) based on direct haplotype phasing without the proband and its feasibility for clinical application in the case of Duchenne Muscular Dystrophy (DMD).\n\nMethodsThirteen singleton-pregnancy families affected by DMD were recruited. Firstly, we resolved maternal haplotypes for each family by performing targeted linked-read sequencing of their high molecular weight DNA, respectively. Then, we identified SNPs of the DMD gene in all carrier mothers and inferred the DMD gene mutation status of all fetuses. Finally, the fetal genotypes were further validated by using chorionic villus sampling.\n\nResultsThe method of directly resolving maternal haplotype through targeted linked-read sequencing was smoothly performed in all participated families. The predicted mutational status of 13 fetuses was correct, which had been confirmed by invasive prenatal diagnosis.\n\nConclusionDirect haplotyping of NIPD based on linked-read sequencing for DMD is accurate.

genetics↗

bioRxiv2019

Comparative transcriptomic and epigenomic analysis identifies key regulators of injury response and neurogenic competence in retinal glia

Injury induces retinal Muller glia of cold-blooded, but not mammalian, vertebrates to regenerate neurons. To identify gene regulatory networks that control neuronal reprogramming in retinal glia, we comprehensively profiled injury-dependent changes in gene expression and chromatin accessibility in Muller glia from zebrafish, chick and mice using bulk RNA-Seq and ATAC-Seq, as well as single-cell RNA-Seq. Cross-species integrative analysis of these data, together with functional validation, identified evolutionarily conserved and species-specific gene networks controlling glial quiescence, gliosis and neurogenesis. In zebrafish and chick, transition from the resting state to gliosis is essential for initiation of retinal regeneration, while in mice a dedicated network suppresses neurogenic competence and restores quiescence. Selective disruption of NFI family transcription factors, which maintain and restore quiescence, enables Muller glia to proliferate and generate neurons in adult mice following retinal injury. These findings may aid in the design of cell-based therapies aimed at restoring retinal neurons lost to degenerative disease. Summary sentenceThis study identifies gene regulatory networks controlling proliferative and neurogenic competence in retinal Muller glia.

neuroscience↗

bioRxiv2019

New genotype invasion of dengue virus serotype 1 drove massive outbreak in Guangzhou, China

BackgroundDengue fever is a mosquito-borne infectious disease that has caused major health problems. Variations in dengue virus (DENV) genes are important features of epidemic outbreaks. However, the associations of DENV genes with epidemic scale have not been extensively examined. Here, we assessed new genotype invasion of DENV-1 isolated from Guangzhou in China to evaluate associations with epidemic outbreaks.\n\nMethodology/Principal FindingsWe used DENV-1 strains isolated from sera of dengue cases from 2002 to 2016 in Guangzhou for complete genome sequencing. A neighbor-joining phylogenetic tree was constructed to elucidate the genotype characteristics and determine if new genotype invasion correlated with major outbreaks. In our study, a new genotype invasion event was observed during each significant outbreak period in 2002-2003, 2006-2007 and 2013-2014. Genotype II was the main epidemic genotype in 2003 and before. Invasion of genotype I in 2006 caused an unusual outbreak with 765 cases (relative risk (RR)=16.24, 95% confidence interval (CI) =12.41-21.25). At the middle and late stages of the 2013 outbreak, genotype III was introduced to Guangzhou as a new genotype invasion responsible for 37340 cases with RR 541.73 (95%CI=417.78-702.45), after which genotypes I and III began co-circulating. Base mutations occurred after new genotype invasion, and the gene sequence of NS3 protein had the lowest average similarity ratio (99.82%), followed by the gene sequence of E protein (99.86%), as compared to the 2013 strain.\n\nConclusions/SignificanceGenotype replacement and co-circulation of multiple DENV-1 genotypes were observed. New genotype invasion was highly correlated with local unusual outbreaks. In addition to DENV-1 genotype I in the unprecedented outbreak in 2014, new genotype invasion by DENV-1 genotype III occurred in Guangzhou.\n\nAuthor SummaryNew genotype invasion of dengue virus highly correlates with the massive outbreaks. In this study, we examined the association of the genotype of dengue virus serorype 1 (DENV-1) from human cases through complete genome sequencing with outbreak scale during 2002 and 2016 in Guangzhou, China. It was observed that genotype replacement and co-circulation of multiple genotypes occurred. Most importantly, it indicated that new genotype invasion was highly related with local unusual outbreaks in major outbreak periods in 2002-2003, 2006-2007 and 2013-2014. DENV-1 genotype II was the main epidemic genotype in 2003 and before. Invasion of genotype I in 2006 caused an unusual outbreak with 765 cases reported. In addition to genotype I circulation, new genotype invasion by genotype III was the key determinant for the 2014 massive outbreak reaching the highest number of cases with 37340. Furthermore, base mutations appeared after genotype III invasion, and the gene sequence of NS3 protein had the lowest average similarity ratio, followed by the gene sequence of E protein, as compared to the 2013 strain.

epidemiology↗

bioRxiv2019

Diversity and some bioactivities of soil actinomycetes from southwestern China

With the natural medicine exploring, the actinomycetes (actinobacteria) have gotten more and more recognition. 815 soil samples were collected from six areas in the southwestern China. 7063 purified strains of actinomycetes were isolated from these samples by using four media. The 16S rRNA gene sequences of 1998 selected strains of the 7063 were determined, and the phylogenetic analysis was carried out. The diversity of actinomycetes is analyzed. Total 33 genera of actinomycetes as the purified cultivation were identified from these soil samples. 14, 13, 5, 9 and 26 genera of actinobacteria were identified from E, A, B, D, C and F area respectively, and the communities of actinomycetes are very different from each other. The diversity of Xishuangbanna (F area) is the richest, and 26 genera were isolated. That of Emei and Qingcheng Mountain (C area) is monotone, and only five genera were isolated. 158 of 1998 strains (7.9 %) are possible new species. Antimicrobial activities of 1070 selected strains against 11 bacteria and fungi were tested using agar well diffusion method, and biosynthetic genes of type I and II polyketide synthases (PKS I, PKS II), nonribosomal peptide synthase (NRPS) and polygene cytochrome P450 hydroxylase (CYP) of 1036 selected strains were detected by PCR. High rate of antimicrobial activity and the four antibiotic biosynthetic genes existed in these actinomycetes. Results of this study indicates that firstly more unknown actinomycetes can be obtained from soil samples, specially primeval tropical forests. Second, isolation methods for actinomycetes must be continually improved and improved.\n\nImportanceFirst, discarding repeat of a mass of known microbes and compounds is very difficult. Second, pharmaceuticals development can still not overtake the increase of resistance of pathogens to antibiotics, and new diseases continuously and fleetly occur. Soil actinomycetes of these regions are researched few by microbiologist yet. In order to get much more unknown actinomycetes for discovery of new bioactive metabolites, the actinomycetes of forest soil in southwestern China were isolated and identified. Anti-microbial activities and synthetic gene clusters of four kinds of antibiotics of some selected strains were detected.

microbiology↗

bioRxiv2019

Single cell RNA-Seq analysis identifies molecular mechanisms controlling hypothalamic patterning and differentiation.

The hypothalamus is a central regulator of many innate behaviors essential for survival, but the molecular mechanisms controlling hypothalamic patterning and cell fate specification are poorly understood. To identify genes that control hypothalamic development, we have used single-cell RNA sequencing (scRNA-Seq) to profile mouse hypothalamic gene expression across 12 developmental time points between embryonic day 10 and postnatal day 45. This identified genes that delineated clear developmental trajectories for all major hypothalamic cell types, and readily distinguished major regional subdivisions of the developing hypothalamus. By using our developmental dataset, we were able to rapidly annotate previously unidentified clusters from existing scRNA-Seq datasets collected during development, and to identify the developmental origins of major neuronal populations of the ventromedial hypothalamus. We further show that our approach can rapidly and comprehensively characterize mutants that have altered hypothalamic patterning, identifying Nkx2.1 as a negative regulator of prethalamic identity. These data serve as a resource for further studies of hypothalamic development, physiology and dysfunction.

neuroscience↗

bioRxiv2019

An omnidirectional visualization model of personalized gene regulatory networks

Gene regulatory networks (GRNs) have been widely used as a fundamental tool to reveal the genomic mechanisms that underlie the organisms response to environmental and developmental cues. Standard approaches infer GRNs as holistic graphs of gene co-expression, but such graphs cannot quantify how gene-gene interactions differentiate among organisms and how they alter structurally across spatiotemporal gradients. Here, we develop a generalized framework for inferring informative, dynamic, omnidirectional, and personalized GRNs (idopGRNs) from routine transcriptional experiments. This framework is constructed by a system of quasi-dynamic ordinary differential equations (qdODEs) derived from the combination of ecological and evolutionary theories. We reconstruct idopGRNs from a clinical genomic study and illustrate how network structure and organization affect surgical response to infrainguinal vein bypass grafting and the outcome of grafting. idopGNRs may shed light on genotype-phenotype relationships and provide valuable information for personalized medicine.

bioinformatics↗

bioRxiv2019

Ablation of tanycytes of the arcuate nucleus and median eminence increases visceral adiposity and decreases insulin sensitivity in male mice.

Tanycytes are radial glial cells located in the mediobasal hypothalamus. Recent studies have proposed that tanycytes play an important role in hypothalamic control of energy homeostasis, although this has not been directly tested. Here, we report the phenotype of mice in which tanycytes of the arcuate nucleus and median eminence were conditionally ablated. Although the CSF-hypothalamic barrier was rendered more permeable, the blood-hypothalamic barrier was not altered. The metabolic effects of tanycyte ablation were likewise moderate. However, we consistently observed a significant increase in visceral fat distribution accompanying insulin insensitivity, but only in male mice, and without an effect on either body weight or food intake. A high-fat diet accelerated overall body weight gain in tanycyte-ablated mice, but the development of visceral adiposity and insulin insensitivity was attenuated. These results clarify the extent to which tanycytes regulate energy metabolism, and indicate a role for tanycytes in controlling body adiposity.

physiology↗

bioRxiv2019

Chromosome-level de novo assembly of the pig-tailed macaque genome using linked-read sequencing and HiC proximity scaffolding

Old world monkey species share over 93% genome homology with humans and develop many disease phenotypes similar to those of humans, making them highly valuable animal models for the study of numerous human diseases. However, the quality of genome assembly and annotation for old world monkeys including macaque species lags behind the human genome effort. To close this gap and enhance functional genomics approaches, we employed a combination of de novo linked-read assembly and scaffolding using proximity ligation assay (HiC) to assemble the pig-tailed macaque (Macaca nemestrina) genome. This combinatorial method yielded large scaffolds at chromosome-level with a scaffold N50 of 127.5 Mb; the 23 largest scaffolds covered 90% of the entire genome. This assembly revealed large-scale rearrangements between pig-tailed macaque chromosomes 7,12, and13 and human chromosomes 2, 14, and 15.

genomics↗