Wei Xu

Bio: Wei Xu is an academic researcher from Southern University of Science and Technology. The author has contributed to research in topics: Embryoid body & Embryonic stem cell. The author has an hindex of 1, co-authored 3 publications receiving 1 citations.

A plate-based single-cell ATAC-seq workflow for fast and robust profiling of chromatin accessibility

Abstract: Profiling chromatin accessibility at the single-cell level provides critical information about cell type composition and cell-to-cell variation within a complex tissue. Emerging techniques for the interrogation of chromatin accessibility in individual cells allow investigation of the fundamental mechanisms that lead to the variability of different cells. This protocol describes a fast and robust method for single-cell chromatin accessibility profiling based on the assay for transposase-accessible chromatin using sequencing (ATAC-seq). The method combines up-front bulk Tn5 tagging of chromatin with flow cytometry to isolate single nuclei or cells. Reagents required to generate sequencing libraries are added to the same well in the plate where cells are sorted. The protocol described here generates data of high complexity and excellent signal-to-noise ratio and can be combined with index sorting for in-depth characterization of cell types. The whole experimental procedure can be finished within 1 or 2 d with a throughput of hundreds to thousands of nuclei, and the data can be processed by the provided computational pipeline. The execution of the protocol only requires basic techniques and equipment in a molecular biology laboratory with flow cytometry support. This protocol describes a plate-based ATAC-seq assay that combines up-front bulk tagging of accessible DNA by the Tn5 transposase with FACS sorting for robust and cost-efficient profiling of chromatin accessibility in single cells.

Genome-wide Interrogation of Protein-DNA Interactions in Mammalian Cells Using ChIPmentation.

Abstract: Summary Mapping the genomic locations of chromatin-associated proteins, such as transcription factors and histone modifications, is key to understanding the mechanisms of transcriptional regulation. ChIPmentation offers a simple and robust way of investigating the genomic binding sites of a protein using relatively low-input material. Here, we present a detailed protocol for the key steps that lead to a successful ChIPmentation experiment, as well as a quick analysis pipeline to examine the data. For complete details on the use and execution of this protocol, please refer to Schmidl et al. (2015) . For example data produced by this protocol, please refer to Henriksson et al. (2019) and Zhang et al. (2019) .

A Modified SMART-Seq Method for Single-Cell Transcriptomic Analysis of Embryoid Body Differentiation

Abstract: Embryoid bodies (EBs) are aggregate of cells that contain three embryonic germ layers. They can be formed by direct differentiation from pluripotent embryonic stem cells (ESCs), which serves as a useful model for understanding early embryo development. Due to the mixture of different cell types, it is necessary to investigate EBs at the single-cell level. Here, we describe a robust and straightforward method for single-cell gene expression profiling during mouse EB differentiation from mouse ESCs (mESCs). The protocol is modified from a widely used method in the SMART-seq family, which only requires standard molecular biology techniques and lab equipment. It allows for accurate 3' counting of transcript at the single-cell level, which helps reveal cellular identities during EB formation. Combined with perturbation experiments, the method provides an opportunity for mechanistic studies of embryo development at the single-cell level.

Recent advances in single-cell sequencing technologies

Abstract: Abstract Single-cell omics sequencing was first achieved for the transcriptome in 2009, which was followed by fast development of technologies for profiling the genome, DNA methylome, 3D genome architecture, chromatin accessibility, histone modifications, etc., in an individual cell. In this review we mainly focus on the recent progress in four topics in the single-cell omics field: single-cell epigenome sequencing, single-cell genome sequencing for lineage tracing, spatially resolved single-cell transcriptomics and third-generation sequencing platform-based single-cell omics sequencing. We also discuss the potential applications and future directions of these single-cell omics sequencing technologies for different biomedical systems, especially for the human stem cell field.

ISSAAC-seq enables sensitive and flexible multimodal profiling of chromatin accessibility and gene expression in single cells

Abstract: Joint profiling of chromatin accessibility and gene expression from the same single cell provides critical information about cell types in a tissue and cell states during a dynamic process. Here, we develop in situ sequencing hetero RNA-DNA-hybrid after assay for transposase-accessible chromatin-sequencing (ISSAAC-seq), a highly sensitive and flexible single-cell multi-omics method to interrogate chromatin accessibility and gene expression from the same single nucleus. We demonstrated that ISSAAC-seq is sensitive and provides high quality data with orders of magnitude more features than existing methods. Using the joint profiles from over 10,000 nuclei from the mouse cerebral cortex, we uncovered major and rare cell types and cell-type specific regulatory elements and identified heterogeneity at the chromatin level within established cell types defined by gene expression. Finally, we revealed distinct dynamics and relationships of gene expression and chromatin accessibility during an oligodendrocyte maturation trajectory.

Single-cell omics: Overview, analysis, and application in biomedical science

Abstract: Single-cell sequencing methods provide the highest resolution insight into cellular heterogeneity. Owing to their rapid growth and decreasing cost, they are now widely accessible to scientists worldwide. Single-cell technologies enable analysis of a large number of cells, making them powerful tools to characterise rare cell types and refine our understanding of diverse cell states. Moreover, single-cell application in biomedical sciences helps to unravel mechanisms related to disease pathogenesis and outcome. In this Viewpoint, we briefly describe existing single-cell methods (genomics, transcriptomics, epigenomics, proteomics, and mulitomics), comment on available analysis tools, and give examples of method applications in the biomedical field.