Project description:We introduce poly-adenine CRISPR gRNA-based single-cell RNA-sequencing (pAC-Seq), a method that enables the direct observation of guide RNAs (gRNAs) in scRNA-seq. We use pAC-Seq to assess the phenotypic consequences of CRISPR/Cas9 based alterations of gene cis-regulatory regions. We show that pAC-Seq is able to detect cis-regulatory-induced alteration of target gene expression even when biallelic loss of target gene expression occurs in only ~5% of cells. This low rate of biallelic loss significantly increases the number of cells required to detect the consequences of changes to the regulatory genome, but can be ameliorated by transcript-targeted sequencing. Based on our experimental results we model the power to detect regulatory genome induced transcriptomic effects based on the rate of mono/biallelic loss, baseline gene expression, and the number of cells per target gRNA.
Project description:Comparison of CoV 3'UTR cis-acting element interactome to link the cis-acting element to coronavirus replication by LC-MS/MS. The study is performed by in vitro-transcribed RNA followed by RNA-protein pull-down assay. In addition, the concluded results are decided by comparison between the biological processes derived from analysis of interactome and the replication efficiency.
Project description:Comparison of CoV 3'UTR cis-acting element interactome to link the cis-acting element to coronavirus replication by LC-MS/MS. The study is performed by in vitro-transcribed RNA followed by RNA-protein pull-down assay. In addition, the concluded results are decided by comparison between the biological processes derived from analysis of interactome and the replication efficiency.
Project description:We introduce poly-adenine CRISPR gRNA-based single cell RNA-sequencing (pAC-Seq), a method enabling simultaneous observation of mutagenic guide RNAs (gRNAs) and their transcriptional consequences in single cell RNA sequencing (scRNA-seq) data. We have made gRNAs robustly visible in scRNA-seq data while maintaining full activity by modifying them with a hardcoded poly-adenine tract. We apply pAC-Seq to study the transcriptomic effects of non-coding CRISPR/Cas9-induced mutations in a pooled screening format. pAC-Seq is a simple, robust, and broadly applicable method of measuring the global effects of genomic mutation.
Project description:Liver cancer susceptibility varies between strains of experimental animal models due to multiple genetic and epigenetic factors. We used DNase I hypersensitivity mapping and transcriptomic profiling to investigate cis-regulatory element and transcriptional perturbations associated with the early stages of phenobarbital (PB)-mediated liver tumor promotion in susceptible versus resistant mouse strains (B6C3F1 versus C57BL/6).
Project description:Thymic central tolerance is essential to preventing autoimmunity. In medullary thymic epithelial cells (mTECs), the Autoimmune regulator (Aire) gene plays an essential role in this process by driving the expression of a diverse set of tissue-specific antigens (TSAs), which are presented and help tolerize self-reactive thymocytes. Interestingly, Aire has a highly tissue-restricted pattern of expression, with only mTECs and peripheral extrathymic Aire-expressing cells (eTACs) known to express detectable levels in adults. Despite this high level of tissue specificity, the cis-regulatory elements that control Aire expression have remained obscure. We used sequence conservation analysis and ChIP-seq against the enhancer-associated histone mark H3K27ac to identify a candidate Aire cis-regulatory element. There is enrichment of H3K27ac near this element, ACNS1, in mTECs and the element also has characteristics of being NF-κB-responsive. Finally, we find that this element is essential for Aire expression in vivo and necessary to prevent spontaneous autoimmunity, reflecting the importance of this regulatory DNA element in promoting immune tolerance. Two experimental groups (GFP neg mTECs and GFP pos mTECs), each with three samples, and one control sample (D10 Th2 cells).
Project description:Here we report a highly scalable strategy for unbiased discovery and functional characterization of cis regulatory elements in the genome. These results demonstrate the utility of our cis element discovery strategy and reveal the dual function of gene promoters: they not only initiate transcription of their own genes, but could also control transcription of nearby genes.