Project description:Alternative transcription start sites (TSSs) usage plays a critical role in gene transcription regulation in mammals. However, precisely identifying alternative TSSs remains challenging at the genome-wide level. Here, we report a single-cell genomic technology for alternative TSSs annotation and cell heterogeneity detection. Here, we utilize Fluidigm C1 system to capture individual cells of interest, SMARTer cDNA synthesis kit to recover full-length cDNA, then dual priming oligonucleotide system to specifically enrich 5’-end tags for genomic analysis.
Project description:Most genes are transcribed from multiple transcription start sites (TSSs), defined as alternative TSSs, which are highly regulated and can lead to various gene regulatory outcomes including changes in translation efficiency and protein isoforms. Transcription factors and chromatin regulators control alternative TSS selection. DNA supercoiling affects multiple aspects of transcription including transcription initiation. However, its regulatory effect on genes with multiple TSSs is not known. Here we investigated how DNA supercoiling impacts alternative TSS usage in Saccharomyces cerevisiae. We depleted topoisomerases during early meiosis, where alternative TSS usage is prevalent, and applied an improved TSS sequencing protocol. We show that supercoiling affects alternative TSS usage of almost 600 genes. Increased alternative and aberrant TSS usage were observed near and within open reading frames, likely resulting from transcription-induced supercoiling originating from upstream alternative TSSs. DNA supercoiling had the greatest impact on genes with a dominant alternative TSS, significant spacing between alternative TSSs, and greater overall length. Our results establish that DNA supercoiling release during transcription is critical for correct TSS selection.
Project description:More than half of human protein-coding genes have an alternative transcription start site (TSS). We aimed to investigate the contribution of alternative TSSs to the acute-stress–induced transcriptome response in human tissue (skeletal muscle) using the cap analysis of gene expression approach. TSSs were examined at baseline and during recovery after acute stress (a cycling exercise). We identified 44,680 CAGE TSS clusters (including 3,764 first defined) belonging to 12,268 genes and annotated for the first time 290 TSSs belonging to 163 genes. The transcriptome dynamically changes during the first hours after acute stress; the change in the expression of 10% of genes was associated with the activation of alternative TSSs, indicating differential TSSs usage. The majority of the alternative TSSs do not increase proteome complexity suggesting that the function of thousands of alternative TSSs is associated with the fine regulation of mRNA isoform expression from a gene due to the transcription factor-specific activation of various alternative TSSs. We identified individual muscle promoter regions for each TSS using muscle open chromatin data (ATAC-seq and DNase-seq). Then, using the positional weight matrix approach we predicted time course activation of “classic” transcription factors involved in response of skeletal muscle to contractile activity, as well as diversity of less/un-investigated factors. Transcriptome response induced by acute stress related to activation of the alternative TSSs indicates that differential TSSs usage is an essential mechanism of fine regulation of gene response to stress stimulus. A comprehensive resource of accurate TSSs and individual promoter regions for each TSS in muscle was created. This resource together with the positional weight matrix approach can be used to accurate prediction of TFs in any gene(s) of interest involved in the response to various stimuli, interventions or pathological conditions in human skeletal muscle.
Project description:We reported a Concanavalin A-based Barcoding Strategy (CASB) for single-cell and single-nucleus sample multiplexing, which could be followed by different single-cell sequencing techniques. The method involves minimal sample processing, thereby preserving intact transcriptomic or epigenomic patterns. Besides sample multiplexing, the CASB could further improve data quality through doublet identification.
Project description:We reported a Concanavalin A-based Barcoding Strategy (CASB) for single-cell and single-nucleus sample multiplexing, which could be followed by different single-cell sequencing techniques. The method involves minimal sample processing, thereby preserving intact transcriptomic or epigenomic patterns. Besides sample multiplexing, the CASB could further improve data quality through doublet identification.
Project description:We reported a Concanavalin A-based Barcoding Strategy (CASB) for single-cell and single-nucleus sample multiplexing, which could be followed by different single-cell sequencing techniques. The method involves minimal sample processing, thereby preserving intact transcriptomic or epigenomic patterns. Besides sample multiplexing, the CASB could further improve data quality through doublet identification.
Project description:We reported a Concanavalin A-based Barcoding Strategy (CASB) for single-cell and single-nucleus sample multiplexing, which could be followed by different single-cell sequencing techniques. The method involves minimal sample processing, thereby preserving intact transcriptomic or epigenomic patterns. Besides sample multiplexing, the CASB could further improve data quality through doublet identification.