Biology subjects

Shi, M.

Publications and source records attributed to Shi, M..

10 recordsLinked to original sources

bioRxiv2018

Characterisation of the faecal virome of captive and wild Tasmanian devils using virus-like particles metagenomics and meta-transcriptomics

BackgroundThe Tasmanian devil is an endangered carnivorous marsupial threatened by devil facial tumour disease (DFTD). While research on DFTD has been extensive, little is known about the viruses present in devils, and whether any of these are of potential conservation relevance for this endangered species.\n\nMethodsUsing both metagenomics based on virus-like particle (VLP) enrichment and sequence-independent amplification (VLP metagenomics), and meta-transcriptomics based on bulk RNA sequencing, we characterised and compared the faecal viromes of captive and wild Tasmanian devils.\n\nResultsA total of 54 devil faecal samples collected from captive (n = 2) and wild (n = 4) populations were processed for virome characterisation using both approaches. We detected many novel, highly divergent viruses, including vertebrate viruses, bacteriophage and other dietary associated plant and insect viruses. In total, 18 new vertebrate viruses, including novel sapelovirus, astroviruses, bocaviruses, papillomaviruses and gammaherpesvirus were identified, as well as known mammalian pathogens including rabbit haemorrhagic disease virus 2 (RHDV2). Captive devils showed significantly lower levels of viral diversity than wild devils. Comparison of the two methodological approaches revealed substantial differences in the number and types of viruses detected, with meta-transcriptomics mainly identifying RNA viruses, and VLP metagenomics largely identifying DNA viruses.\n\nConclusionThis study has greatly expanded our knowledge of eukaryotic viruses in the Tasmanian devil and provides important baseline information that will contribute to the conservation and captive management of this endangered species. In addition, our results showed that a combination of VLP metagenomics and meta-transcriptomics may be a more comprehensive approach to virome characterisation than either method alone.

molecular biology↗

bioRxiv2018

A divergent hepatitis D-like agent in birds

Hepatitis delta virus (HDV) is currently only found in humans, and is a satellite virus that depends on hepatitis B virus (HBV) envelope proteins for assembly, release and entry. Using meta-transcriptomics, we identified the genome of a novel HDV-like agent in ducks. Sequence analysis revealed secondary structures that were shared with HDV, including self-complementarity and ribozyme features. The predicted viral protein shares 32% amino acid similarity to the small delta antigen of HDV and comprises a divergent phylogenetic lineage. The discovery of an avian HDV-like agent has important implications for the understanding of the origins of HDV and subviral agents.\n\nImportanceHepatitis delta virus (HDV) is currently only found in humans, and coinfections of HDV and Hepatitis B virus (HBV) in humans result in severe liver disease. There are a number of hypotheses for the origin of HDV, although a key component of all is that HDV only exists in humans. Here, we describe a novel deltavirus-like agent identified in wild birds. Although this agent is genetically divergent, it exhibits important similarities to HDV, such as the presence of ribosymes and self-complementarity. The discovery of an avian HDV-like agent challenges our understanding of both the origin and the co-evolutionary relationships of subviral agents with helper viruses.

molecular biology↗

bioRxiv2018

Extensive Diversity of RNA Viruses in Australian Ticks

Understanding the microbiome of ticks in Australia is of considerable interest given the ongoing debate over whether Lyme disease, and its causative agent the bacterium Borrelia burgdorferi senso lato, are present in Australia. The diversity of bacteria infecting Australian ticks has been the subject of a number of studies using both culture and metagenomics based techniques. However, little is known about the virome of Australian ticks, including those that may have the potential to infect mammalian species. We used a meta-transcriptomics approach to reveal the viral diversity within Australian ticks collected from two locations on the central-east coast of Australia, including metropolitan Sydney. From this we identified 19 novel species of RNA virus belonging to 10 families, as well as one previously described RNA virus. The majority of these viruses clustered phylogenetically with arthropod-associated viruses suggesting that they do not utilize mammalian hosts. However, two novel viruses discovered in ticks feeding on bandicoot marsupials clustered closely within the mammalian associated Hepacivirus and Pestivirus genera (Flaviviridae). Notably, another bandicoot tick yielded a novel Coltivirus (Reoviridae) - a group of largely tick-associated viruses containing the known human pathogen Colorado tick fever virus and its relative Eyach virus. Importantly, our transcriptomic data provided no evidence for the presence of B. burgdorferi s.l.. in any tick sample, providing further evidence against the presence of Lyme Disease in Australia. In sum, this study reveals that Australian ticks harbor a diverse virome, including some viruses that merit additional screening in the context of emerging infectious disease.\n\nIMPORTANCEEach year a growing number of individuals along the east coast of Australia experience debilitating disease following tick bites. As there is no evidence for the presence of the causative agent of Lyme disease, Borrelia Burgdorferi seno lato, in Australian ticks, the etiological basis of this disease syndrome remains controversial. To characterize the viruses associated with Australian ticks, particularly those that might be associated with mammalian infection, we performed unbiased RNA sequencing on 146 ticks collected across two locations along the coast of New South Wales, Australia. This revealed 19 novel RNA viruses from a diverse set of families. Notably, three of these viruses were related to known mammalian viruses, including one that fell within the genus Coltivirus and related to the human pathogen, Colorado tick fever virus.

microbiology↗

bioRxiv2018

Comparative genomic analysis revealed rapid differentiation in the pathogenicity-related gene repertoires between Pyricularia oryzae and Pyricularia penniseti isolated from a Pennisetum grass

BackgroundsPyricularia is a multispecies complex that could infect and cause severe blast disease on diverse hosts, including rice, wheat and many other grasses. Although the genome size of this fungal complex is small [~40 Mbp for Pyricularia oryzae (syn. Magnaporthe oryzae), and ~45 Mbp for P. grisea], the genome plasticity allows the fungus to jump and adapt to new hosts. Therefore, deciphering the genome basis of individual species could facilitate the evolutionary and genetic study of this fungus. However, except for the P. oryzae subgroup, many other species isolated from diverse hosts, such as the Pennisetum grasses, remain largely uncovered genetically.\n\nResultsHere, we report the genome sequence of a pyriform-shaped fungal strain P. penniseti P1609 isolated from a Pennisetum grass (JUJUNCAO) using PacBio SMRT sequencing technology. We performed a phylogenomic analysis of 28 Magnaporthales species and 5 non-Magnaporthales species and addressed P1609 into a Pyricularia subclade that is distant from P. oryzae. Comparative genomic analysis revealed that the pathogenicity-related gene repertoires were fairly different between P1609 and the P. oryzae strain 70-15, including the cloned avirulence genes, other putative secreted proteins, as well as some other predicted Pathogen-Host Interaction (PHI) genes. Genomic sequence comparison also identified many genomic rearrangements.\n\nConclusionTaken together, our results suggested that the genomic sequence of the P. penniseti P1609 could be a useful resource for the genetic study of the Pennisetum-infecting Pyricularia species.

genomics↗

bioRxiv2018

Amino acids stimulate the endosome-to-Golgi trafficking through Ragulator and small GTPase Arl5

The endosome-to-Golgi or endocytic retrograde trafficking pathway is an important post-Golgi recycling route. We made a novel discovery that the retrograde trafficking of cargos is inhibited and stimulated by the absence and presence, respectively, of amino acids (AAs), especially glutamine. By testing components of the AA-stimulated mTORC1 signaling pathway, we demonstrated that SLC38A9, v-ATPase and Ragulator, but not Rag GTPases and mTORC1, are essential for the AA-stimulated trafficking. Arl5, an ARF-like family small GTPase, interacts with Ragulator in an AA-regulated manner and both Arl5 and its effector, the Golgi-associated retrograde protein complex (GARP), are required for the AA-stimulated trafficking. We have therefore identified a mechanistic connection between the nutrient signaling and the retrograde trafficking pathway, whereby SLC38A9 and v-ATPase sense AA-sufficiency and Ragulator functions as a guanine nucleotide exchange factor to activate Arl5, which, together with GARP, a tethering factor, probably facilitates the endosome-to-Golgi trafficking.

cell biology↗

bioRxiv2018

MAIT cells contribute to protection against lethal influenza infection in vivo

Mucosal associated invariant T (MAIT) cells are evolutionarily-conserved, innate-like lymphocytes which are abundant in human lungs and can contribute to protection against pulmonary bacterial infection. MAIT cells are also activated during human viral infections, yet it remains unknown whether MAIT cells play a significant protective or even detrimental role during viral infections in vivo. Using murine experimental challenge with two strains of influenza A virus, we show that MAIT cells accumulated and were activated early in infection, with upregulation of CD25, CD69 and Granzyme B, peaking at 5 days post infection. Activation was modulated via cytokines independently of MR1. MAIT cell-deficient MR1-/- mice showed enhanced weight loss and mortality to severe (H1N1) influenza. This was ameliorated by prior adoptive transfer of pulmonary MAIT cells in both immunocompetent and immunodeficient RAG2-/-{gamma}C-/- mice. Thus, MAIT cells contribute to protection during respiratory viral infections, and constitute a potential target for therapeutic manipulation.

immunology↗

bioRxiv2018

Acidic microenvironment shaped by lactate accumulation promotes pluripotency through multiple mechanisms

Enhanced glycolysis is a distinct feature associated with numerous stem cells and cancer cells. However, little is known about its regulatory roles in gene expression and cell fate determination. Here we show that acidic environment shaped by lactate accumulation promotes the self-renewal and pluripotency of both mouse and human embryonic stem cells (ESCs). Mechanistically, acidic pH reduces the tri-methylation of H3K27 globally at transcriptional start sites to partially prevent ESC differentiation. In addition, acidic pH stabilizes a large number of mRNAs including pluripotency genes. Furthermore, we found that AGO1 protein is downregulated at acidic conditions, leading to the de-repression of a subset of microRNA targets in low-pH treated ESCs. Altogether, our study provides insights into mechanisms whereby acidic microenvironment produced by enhanced glycolysis regulates gene expression to determine cell fate and has broad implications in the fields of regenerative medicine and cancer biology.

developmental biology↗

bioRxiv2017

Transcription factor SmWRKY1 positively promote the biosynthesis of tanshinones in Salvia miltiorrhiza

Tanshinones, one group of bioactive diterpenes, were widely used in the treatment of cardiovascular diseases. WRKYs play important roles in plant metabolism, but their regulation mechanism in S. miltiorrhiza remains elusive. In this study, one WRKY transcription factor SmWRKY1 was isolated and characterized from S. miltiorrhiza. Multiple sequence alignment and phylogenetic tree analysis showed SmWRKY1 shared high homology with other plant WRKYs such as CrWRKY1. SmWRKY1 were predominantly expressed in leaves and stems, and was responsive to salicylic acid (SA), methyl jasmonate (MeJA) and nitric oxide (NO) treatment. Subcellular localization analysis found that SmWRKY1 was localized in the nucleus. Over-expression of SmWRKY1 significantly elevated the transcripts of genes involved in MEP pathway especially 1-deoxy-D-xylulose 5-phosphate synthase (SmDXS) and 1-deoxy-D-xylulose 5-phosphate reductoisomerase (SmDXR), resulted in over 6 folds increase in tanshinones production in transgenic lines (up to 13.731mg/g dry weight (DW)) compared with the control lines. Dual-luciferase (Dual-LUC) assay showed that SmWRKY1 can positively regulate SmDXR expression by binding to its promoter. Our work revealed that SmWRKY1 participated in the regulation of tanshinones biosynthesis and acted as a positive regulator through activating SmDXR in the MEP pathway, thus discloses a new insight to further excavate the regulation mechanism of tanshinones biosynthesis.

bioengineering↗

bioRxiv2017

NF90/ILF3 is a transcription factor that promotes proliferation over differentiation by hierarchical regulation in K562 erythroleukemia cells

NF90 and splice variant NF110 are DNA- and RNA-binding proteins encoded by the Interleukin enhancer-binding factor 3 (ILF3) gene that regulate RNA splicing, stabilization and export. The role of NF90 in regulating transcription as a DNA-binding protein has not been comprehensively characterized. Here, ENCODE ChIP-seq identified 9,081 genomic sites specifically bound by NF90/110 in K562 cells. One third of binding sites occurred at promoters of annotated genes. NF90/110 binding colocalized with chromatin marks associated with active promoters and strong enhancers. Comparison with 150 ENCODE ChIP-seq experiments revealed that NF90 clustered with transcription factors exhibiting preference for promoters over enhancers (POLR2A, MYC, YY1). Differential gene expression analysis following shRNA knockdown of NF90 in K562 cells revealed that NF90 directly activates transcription factors that drive growth and proliferation (EGR1, MYC), while attenuating differentiation along erythroid lineage (KLF1). NF90/110 binds chromatin to hierarchically regulate transcription factors to promote proliferation and suppress differentiation.

genetics↗

bioRxiv2016

HBP: an integrative and flexible pipeline for the interaction analysis of Hi-C dataset

BackgroundThe spatial organization of interphase chromatin in the nucleus play an important role in gene expression regulation and function. With the rapid development of revolutionized chromosome conformation capture technology and its genome-wide derivatives such as Hi-C, investigation of the genome folding becomes more efficient and convenient. How to robustly deal with these massive datasets and infer accurate 3D model and within-nucleus compartmentalization of chromosomes becomes a new challenge.\n\nResultThe implemented pipeline HBP (Hi-C BED file analysis Pipeline) integrates existing pipelines focusing on individual steps of Hi-C data processing into an all-in-one package with adjustable parameters to infer the consensus 3D structure of genome from raw Hi-C sequencing data. Whats more, HBP could assign statistical confidence estimation for chromatin interactions, and clustering interaction loci according to enrichment tracks or topological structure automatically.\n\nConclusionThe freely available HBP is an optimized and flexible pipeline for analyzing the folding of whole chromosome and interactions between some specific sites from the Hi-C raw sequencing reads to the partially processed datasets. The other complex genetic and epigenetic datasets from public sources such as GWAS, ENCODE consortiums etc. will also easily be integrated into HBP, hence the final output results of HBP could provide a comprehensive in-depth understanding for the specific chromatin interactions, potential molecular mechanisms and biological significance. We believe that HBP is a reliable tool for the rapidly analysis of Hi-C data and will be very useful for a wide range of researchers, particularly those who lack of background in computational biology. HBP is freely accessible at https://github.com/hechao0407/HBP/blob/master/HBP_1.0.tar.gz.

bioinformatics↗