Biology subjects

Zhai, J.

Publications and source records attributed to Zhai, J..

52 records · Page 3Linked to original sources

bioRxiv2022

PPRD: a comprehensive online database for expression analysis of ~45,000 plant public RNA-Seq libraries

High-throughput RNA-sequencing (RNA-seq) has become the most popular technology for profiling gene expression in the last decade due to its low cost and high coverage. As a result, the number of RNA-seq libraries from the plant community has been increasing exponentially in recent years. For major crops, such as maize, rice, soybean, wheat, and cotton, the plant community has collected a total of ~45,000 libraries by 2021. To take full advantage of the bigdata of RNA-seq libraries, an effort to integrate all publicly available libraries via a uniformed processing pipeline and curate them into an easy-to-use searchable database is urgently needed. To address this challenge, here we present a comprehensive web-based platform, Plant Public RNA-seq Database (PPRD, http://ipf.sustech.edu.cn/pub/plantrna/). PPRD consists of a large number of RNA-seq libraries of maize (11,726), rice (19,664), soybean (4,085), wheat (5,816), and cotton (3,483) from Gene Expression Omnibus (GEO), Sequence Read Archive (SRA), European Nucleotide Archive (ENA), and DNA Data Bank of Japan (DDBJ) databases.

plant biology↗

bioRxiv2022

An atlas of plant full-length RNA reveals tissue-specific and evolutionarily-conserved regulation of poly(A) tail length

Introductory paragraphPoly(A) tail is a hallmark of eukaryotic mRNA and its length plays an essential role in regulating mRNA metabolism1-3. However, a comprehensive resource for plant poly(A) tail length has yet to be established. Here, we applied a poly(A)-enrichment-free, Nanopore-based method4,5 to profile full-length RNA with poly(A) tail information in plants. Our atlas contains over 120 million polyadenylated mRNA molecules from seven different tissues of Arabidopsis, as well as the shoot tissue of maize, soybean and rice. In most tissues, the size of plant poly(A) tails shows peaks at approximately 20 and 45 nt, presumably the sizes protected by one and two poly(A) binding proteins (PABP), respectively2,6, while the poly(A) tails in pollen exhibit a distinct pattern with strong peaks centered at 55 and 80 nt. Moreover, poly(A) tail length is regulated in a gene-specific manner -- mRNAs with short half-lives in general have long poly(A) tails, while mRNAs with long half-lives are featured with relatively short poly(A) tails that peak at ~45 nt, suggesting that protection of poly(A) tail in this size by PABP is essential for mRNA stability. Across species, poly(A) tails in the nucleus are almost twice as long as in the cytoplasm, implying a conserved rapid shortening process of poly(A) tail occurs before the mRNA is stabilized in cytoplasm. Our comprehensive dataset lays the groundwork for future functional and evolutionary studies on poly(A) tail length regulation in plants.

molecular biology↗

bioRxiv2022

Pore-C Simultaneously Captures Genome-wide Multi-way Chromatin Interaction and Associated DNA Methylation Status in Arabidopsis

In the past decade, genome-wide characterization of the three-dimensional chromatin structure in plants using high-throughput methods has greatly advanced our knowledge in plant genome architecture (Liu and Weigel, 2015; Ouyang et al., 2020). However, due to the limitation of Illumina short-read sequencing, the genome-wide contact map obtained by Hi-C/ChIA-PET is pairwise, and the multi-way interaction can only be inferred from the two-way data. To directly capture multi-way interaction in Arabidopsis, we applied a long-read-based method called Pore-C that directly sequences the DNA fragments joined by proximity-based ligation (Ulahannan et al., 2019).

molecular biology↗

bioRxiv2020

easyMF: A Web Platform for Matrix Factorization-based Biological Discovery from Large-scale Transcriptome Data

With the development of high-throughput experimental technologies, large-scale RNA sequencing (RNA-Seq) data have been and continue to be produced, but have led to challenges in extracting relevant biological knowledge hidden in the produced high-dimensional gene expression matrices. Here, we present easyMF, a user-friendly web platform that aims to facilitate biological discovery from large-scale transcriptome data through matrix factorization (MF). The easyMF platform enables users with little bioinformatics experience to streamline transcriptome analysis from raw reads to gene expression and to decompose expression matrix from thousands of genes to a handful of metagenes. easyMF also offers a series of functional modules for metagene-based exploratory analysis with an emphasis on functional gene discovery. As a modular, containerized and open-source platform, easyMF can be customized to satisfy users specific demands and deployed as a web server for broad applications. easyMF is freely available at https://github.com/cma2015/easyMF. We demonstrated the application of easyMF with four case studies using 940 RNA sequencing datasets from maize (Zea mays L.).

bioinformatics↗

bioRxiv2020

Interactive Web-based Annotation of Plant MicroRNAs with iwa-miRNA

MicroRNAs (miRNAs) are important regulators of gene expression. The large-scale detection and profiling of miRNAs has accelerated with the development of high-throughput small RNA sequencing (sRNA-Seq) techniques and bioinformatics tools. However, generating high-quality comprehensive miRNA annotations remains challenging, due to the intrinsic complexity of sRNA-Seq data and inherent limitations of existing miRNA predictions. Here, we present iwa-miRNA, a Galaxy-based framework that can facilitate miRNA annotation in plant species by combining computational analysis and manual curation. iwa-miRNA is specifically designed to generate a comprehensive list of miRNA candidates, bridging the gap between already annotated miRNAs provided by public miRNA databases and new predictions from sRNA-Seq datasets. It can also assist users to select promising miRNA candidates in an interactive mode through the automated and manual steps, contributing to the accessibility and reproducibility of genome-wide miRNA annotation. iwa-miRNA is user-friendly and can be easily deployed as a web application for researchers without programming experience. With flexible, interactive, and easy-to-use features, iwa-miRNA is a valuable tool for annotation of miRNAs in plant species with reference genomes. We illustrated the application of iwa-miRNA for miRNA annotation of plant species with varying complexity. The sources codes and web server of iwa-miRNA is freely accessible at: http://iwa-miRNA.omicstudio.cloud/.

plant biology↗

bioRxiv2020

Single-nucleus full-length RNA profiling in plants incorporates isoform information to facilitate cell type identification

The broad application of large-scale single-cell RNA profiling in plants has been restricted by the prerequisite of protoplasting. We recently found that the Arabidopsis nucleus contains abundant polyadenylated mRNAs, many of which are incompletely spliced. To capture the isoform information, we combined 10x Genomics and Nanopore long-read sequencing to develop a protoplasting-free full-length single-nucleus RNA profiling method in plants. Our results demonstrated using Arabidopsis root that nuclear mRNAs faithfully retain cell identity information, and single-molecule full-length RNA sequencing could further improve cell type identification by revealing splicing status and alternative polyadenylation at single-cell level.

genomics↗

bioRxiv2020

Co-targeting myelin inhibitors and CSPGs enhances sensory axon regeneration within, but not into, the spinal cord

A major barrier to intraspinal regeneration after dorsal root (DR) injury is the DR entry zone (DREZ), the CNS/PNS interface. DR axons stop regenerating at the DREZ, even if regenerative capacity is increased by a nerve conditioning lesion. This potent blockade has long been attributed to myelin-associated inhibitors and CSPGs, but incomplete lesions and conflicting reports have prevented conclusive agreement. Here we evaluated DR regeneration in mice, using novel strategies to facilitate complete lesions and analyses, selective tracing of proprioceptive and mechanoreceptive axons, and the first simultaneous targeting of Nogo/Reticulon-4, MAG, OMgp, CSPGs and GDNF. Co-eliminating myelin inhibitors and CSPGs elicited regeneration of only a few conditioning-lesioned DR axons across the DREZ. Their absence, however, markedly and synergistically enhanced regeneration of GDNF-stimulated axons, highlighting the importance of sufficiently elevating intrinsic growth capacity. We also conclude that myelin inhibitors and CSPGs are not the primary mechanism stopping axons at the DREZ.

neuroscience↗

bioRxiv2020

Introducing undergraduate students to reverse genetics in the laboratory: a case study of a project-oriented learning (POL) system in Taishan Medical University, China

Biochemistry and molecular biology have become increasingly reliant on experimental experience, because they are difficult subjects to understand from a theoretical approach. The Innovation and Entrepreneurship Training Program was established by the China Ministry of Education to foster the scientific interests and experiences of undergraduate students. Here, we reported on an innovative project-oriented learning (POL) system directed by Taishan Medical University (Named Shandong First Medical University & Shandong Academy of Sciences since February 2019) China, which fused innovative project with biochemical course concepts. This study takes reverse genetics, which is considered to be difficult to understand through course-only learning, as an example. To help undergraduate students understand the principle of reverse genetics, the project involved producing hepatitis C virus in vitro. Furthermore, to give them a comprehensive scientific experience based on their knowledge from textbook, extensive mentorship was provided through the project, including theoretical guidance and technical support for experiments. Assessment showed a comprehensive improvement after participating in these programs. In conclusion, this POL system was a good model that enabled undergraduates to learn more during courses. It also provided a chance to experience hands-on sciences, which might motivate them to pursue a career in science.View Full Text

scientific communication and education↗

bioRxiv2020

Single-cell atlas of human developing and azoospermia patients' testicles reveals the roadmap and defects in somatic microenvironment

Non-obstructive azoospermia (NOA) affects 1% of men. However, the unknowns of NOA pathogenesis and even normal spermatogenic microenvironment establishment severely limit the clinical efficacy of NOA treatment. We profiled > 80,000 human testicular single-cell transcriptomes from 10 healthy donors spanning the range from infant to adult and 7 NOA patients. Sertoli cells, which form the scaffold in the testicular microenvironment, exhibited the most obvious damages in NOA patients. We identified the roadmap of Sertoli cell maturation. Notably, Sertoli cells of patients with congenital causes (Klinefelter syndrome and Y chromosome microdeletions) are mature but with abnormal immune response, while the cells in idiopathic NOA (iNOA) are basically physiologically immature. Furthermore, inhibition of Wnt signaling promotes the maturation of Sertoli cells from iNOA patients, allowing these cells to regain their ability to support germ cell survival. We provide a novel perspective on the development of diagnostic methods and therapeutic targets for NOA.

developmental biology↗

bioRxiv2020

Substrate deformation regulates DRM2-mediated DNA methylation in plants

DNA methylation is an important epigenetic mechanism that critically regulates gene expression and genomic stability. In plants, Domains Rearranged Methyltransferase 2 (DRM2) preferentially mediates CHH methylation (H=C, T, A), a substrate specificity distinct from that of mammalian DNA methyltransferases. However, the underlying mechanism is unknown. Here, we report structure-function characterizations of DRM2-mediated methylation. An arginine finger from the catalytic loop intercalates into DNA minor groove, inducing large DNA deformation that impacts the substrate specificity of DRM2. To accommodate the substrate deformation, the target recognition domain of DRM2 embraces the enlarged DNA major groove via shape complementarity, disruption of which via C397R mutation shifts the substrate specificity of DRM2 toward CHG DNA. This study uncovers DNA deformation as a mechanism in regulating the substrate specificity of DRM2, implicative of transposon-specific repression in plants.

biochemistry↗

bioRxiv2020

Isolation and Characterization of 2019-nCoV-like Coronavirus from Malayan Pangolins

The outbreak of 2019-nCoV in the central Chinese city of Wuhan at the end of 2019 poses unprecedent public health challenges to both China and the rest world1. The new coronavirus shares high sequence identity to SARS-CoV and a newly identified bat coronavirus2. While bats may be the reservoir host for various coronaviruses, whether 2019-nCoV has other hosts is still ambiguous. In this study, one coronavirus isolated from Malayan pangolins showed 100%, 98.2%, 96.7% and 90.4% amino acid identity with 2019-nCoV in the E, M, N and S genes, respectively. In particular, the receptor-binding domain of the S protein of the Pangolin-CoV is virtually identical to that of 2019-nCoV, with one amino acid difference. Comparison of available genomes suggests 2019-nCoV might have originated from the recombination of a Pangolin-CoV-like virus with a Bat-CoV-RaTG13-like virus. Infected pangolins showed clinical signs and histopathological changes, and the circulating antibodies reacted with the S protein of 2019-nCoV. The isolation of a coronavirus that is highly related to 2019-nCoV in the pangolins suggests that these animals have the potential to act as the intermediate host of 2019-nCoV. The newly identified coronavirus in the most-trafficked mammal could represent a continuous threat to public health if wildlife trade is not effectively controlled.

microbiology↗

bioRxiv2019

A comprehensive online database for exploring ~20,000 public Arabidopsis RNA-Seq libraries

Application of Next Generating Sequencing (NGS) technology in transcriptome profiling has greatly improved our understanding of transcriptional regulation at genome-wide scale in the last decade, and tens of thousands of RNA-sequencing (RNA-seq) libraries have been produced by the research community. However, accessing such huge amount of RNA-seq data poses a big challenge for groups that lack dedicated bioinformatic personnel or expensive computational resources. Here, we introduce the Arabidopsis RNA-seq database (ARS), a free, web-accessible, and user-friendly to quickly explore expression level of any gene in 20,000+ publicly available Arabidopsis RNA-seq libraries.

bioinformatics↗

bioRxiv2019

sRNAanno --- a database repository of uniformly-annotated small RNAs in plants

Small RNAs (sRNAs) are essential regulatory molecules, including three mayor classes in plants, microRNAs (miRNAs), phased small interfering RNAs (phased siRNAs or phasiRNAs), and heterochromatic siRNAs (hc-siRNAs). Except miRNAs, the other two classes are not well-annotated and collected in public databases for most sequenced plant genomes. We performed comprehensive sRNA annotation for 138 plant species, which have fully sequenced genomes and public next-generation-sequencing (NGS) sRNA data available. The results are available via an online repository called sRNAanno (www.plantsRNAs.org). Compared to plant miRNAs deposited in miRBase, we obtained much more miRNAs, which are more complete and reliable because of consistent and high-stringent criteria used in our miRNA annotation. sRNAanno also provides free access to genomic information for >16,000 PHAS loci and >21,000,000 hc-siRNA loci annotated from these 138 plants. On the basis of Integrative Genomics Viewer (IGV), we developed a visualization tool for browsing NGS sRNA data (IGV-sRNA), which have been integrated a series of new functions compatible to specific sRNA features. To make sRNA annotation an easy task, sRNAanno also provides free service of sRNA annotation to the community. In summary, sRNAanno and IGV-sRNA are great resources to facilitate the genomic and genetic research of plant small RNAs.

genomics↗

bioRxiv2018

Exact Tests of Zero Variance Component in Presence of Multiple VarianceComponents with Application to Longitudinal Microbiome Study

In the metagenomics studies, testing the association of microbiome composition and clinical conditions translates to testing the nullity of variance components. Computationally efficient score tests have been the major tools. But they can only apply to the null hypothesis with a single variance component and when sample sizes are large. Therefore, they are not applicable to longitudinal microbiome studies. In this paper, we propose exact tests (score test, likelihood ratio test, and restricted likelihood ratio test) to solve the problems of (1) testing the association of the overall microbiome composition in a longitudinal design and (2) detecting the association of one specific microbiome cluster while adjusting for the effects from related clusters. Our approach combines the exact tests for null hypothesis with a single variance component with a strategy of reducing multiple variance components to a single one. Simulation studies demonstrate that our method has correct type I error rate and superior power compared to existing methods at small sample sizes and weak signals. Finally, we apply our method to a longitudinal pulmonary microbiome study of human immunodeficiency virus (HIV) infected patients and reveal two interesting genera Prevotella and Veillonella associated with forced vital capacity. Our findings shed lights on the impact of lung microbiome to HIV complexities. The method is implemented in the open source, high-performance computing language Julia and is freely available at https://github.com/JingZhai63/VCmicrobiome.

genomics↗

bioRxiv2018

The basis of accumulation differences in plant 21-nt reproductive phasiRNAs, and their cis-directed activity

O_LIPost-transcriptional gene silencing in plants results from independent activities of diverse small RNA types. In anthers of grasses, hundreds of loci yield non-coding RNAs that are processed into 21- and 24-nt phased small interfering RNAs (phasiRNAs); these are triggered by miR2118 and miR2275.\nC_LIO_LIWe characterized these \"reproductive phasiRNAs\" from rice panicles and anthers across seven developmental stages. Our computational analysis identified characteristics of the 21-nt reproductive phasiRNAs that impact their biogenesis, stability, and potential functions.\nC_LIO_LIWe demonstrate that 21-nt reproductive phasiRNAs can function in cis to target their own precursors. We observed evidence of this cis regulatory activity in both rice (Oryza sativa) and maize (Zea mays). We validated this activity with evidence of cleavage and a resulting shift in the pattern of phasiRNA production.\nC_LIO_LIWe characterize biases in phasiRNA biogenesis, demonstrating that the Pol II-derived \"top\" strand phasiRNAs are consistently higher abundance than the bottom strand. The first phasiRNA from each precursor overlaps the miR2118 target site, and this impacts phasiRNA accumulation or stability, evident in the weak accumulation of this phasiRNA position. Additional influences on this first phasiRNA duplex include the sequence composition and length, and we show that these factors impact Argonaute loading.\nC_LI

plant biology↗

bioRxiv2017

PEA: an integrated R toolkit for plant epitranscriptome analysis

MotivationThe epitranscriptome, also known as chemical modifications of RNA (CMRs), is a newly discovered layer of gene regulation, the biological importance of which emerged through analysis of only a small fraction of CMRs detected by high-throughput sequencing technologies. Understanding of the epitranscriptome is hampered by the absence of computational tools for the systematic analysis of epitranscriptome sequencing data. In addition, no tools have yet been designed for accurate prediction of CMRs in plants, or to extend epitranscriptome analysis from a fraction of the transcriptome to its entirety.\n\nResultsHere, we introduce PEA, an integrated R toolkit to facilitate the analysis of plant epitranscriptome data. The PEA toolkit contains a comprehensive collection of functions required for read mapping, CMR calling, motif scanning and discovery, and gene functional enrichment analysis. PEA also takes advantage of machine learning technologies for transcriptome-scale CMR prediction, with high prediction accuracy, using the Positive Samples Only Learning algorithm, which addresses the two-class classification problem by using only positive samples (CMRs), in the absence of negative samples (non-CMRs). Hence PEA is a versatile epitranscriptome analysis pipeline covering CMR calling, prediction, and annotation, and we describe its application to predict N6-methyladenosine (m6A) modifications in Arabidopsis thaliana. Experimental results demonstrate that the toolkit achieved 71.6% sensitivity and 73.7% specificity, which is superior to existing m6A predictors. PEA is potentially broadly applicable to the in-depth study of epitranscriptomics.\n\nAvailabilityPEA is implemented using R and available at https://github.com/cma2015/PEA.

bioinformatics↗