Project description:PPARγ is a master transcriptional regulator of adipogenesis. Hence, the identification of PPARγ coactivators should help reveal mechanisms controlling gene expression in adipose tissue development and physiology. We show that the non-coding RNA Steroid receptor RNA Activator, SRA, associates with PPARγ and coactivates PPARγ-dependent reporter gene expression. Overexpression of SRA in ST2 adipocyte precursor cells promotes their differentiation into adipocytes. Conversely, knockdown of endogenous SRA inhibits 3T3-L1 preadipocyte differentiation. Microarray analysis reveals hundreds of SRA-responsive genes in adipocytes, including genes in cell cycle, insulin and TNFα signaling pathways. Some functions of SRA may involve mechanisms other than coactivation of PPARγ. SRA increases insulin-stimulated glucose uptake in adipocytes. SRA promotes S-phase entry during mitotic clonal expansion, decreases expression of cyclin-dependent kinase inhibiters p21Cip1 and p27Kip1, and increases phosphorylation of Cdk1/Cdc2. SRA also inhibits the TNFα-induced phosphorylation of c-Jun NH2-terminal kinase. In conclusion, SRA enhances adipogenesis and adipocyte function through multiple pathways.
Project description:We performed Chromatin Isolation by RNA Purification (ChIRP) of SRA and ChIP of p68 following by high-throughput sequencing in NTERA2 cell line. We find that SRA localizes with p68 genome-wide at genes whose function is involved in embryonic development.
Project description:CCCTC-binding factor (CTCF) is a DNA-binding protein that plays important roles in chromatin organization, though the mechanism by which CTCF carries out these functions is not fully understood. Recent studies show that CTCF recruits the cohesin complex to insulator sites and that cohesin is required for insulator activity. Here we have shown that the DEAD box RNA helicase p68 (DDX5) and its associated noncoding RNA, steroid receptor RNA activator (SRA), form a complex with CTCF that is essential for insulator function. p68 was detected at CTCF sites in the IGF2/H19 imprinted control region (ICR) as well as other genomic CTCF sites. In vivo depletion of SRA or p68 reduced CTCF-mediated insulator activity at the IGF2/H19 ICR, increased levels of IGF2 expression, and increased interactions between the endodermal enhancer and IGF2 promoter. p68/SRA also interacts with members of the cohesin complex. Depletion of either p68 or SRA does not affect CTCF binding to its genomic sites, but it does reduce cohesin binding. The results suggest that p68/SRA stabilizes the interaction of cohesin with CTCF, by binding to both, and is required for proper insulator function.
Project description:We performed Chromatin Isolation by RNA Purification (ChIRP) of SRA and ChIP of p68 following by high-throughput sequencing in NTERA2 cell line. We find that SRA localizes with p68 genome-wide at genes whose function is involved in embryonic development. SRA ChIRP and p68 ChIP of triplicate samples.
Project description:The human steroid receptor RNA activator (SRA) gene encodes both non-coding RNAs (ncRNAs) and protein-generating isoforms. However, the breadth of endogenous target genes that might be regulated by SRA RNAs remains largely unknown. To address this, we depleted SRA RNA in two human cancer cell lines (HeLa and MCF-7) with small interfering RNAs, then assayed for changes in gene expression by microarray analyses using Affymetrix HGU133+2 arrays. We also tested if SRA depletion affects estradiol-regulated genes in MCF-7 breast cancer cells.
Project description:We report a novel function of the lncRNA SRA in regulation of global gene expression through direct chromatin binding in human erythroleukemia cell line K562 and in primary human proerythroblasts derived from HSCs. We demonstrate that SRA, together with CTCF, H3K4me3, and H3K27me3, occupies various genomic regions. Further, SRA facilitates transcriptome-wide expression of erythroid program and expression of erythroid markers in K562 and in primary human proerythroblasts. Hence, a possible function of the lncRNA SRA during erythroid development is to promote transcription of erythroid genes and therefore erythropoiesis.
Project description:We employed next generation sequencing to examine whether knocking down the steroid receptor RNA activator (SRA) gene significantly affect the expression levels of certain genes in MCF-7 cells. MCF-7 cells were transfected with either a pool of four non-target control siRNAs or a pool of four SRA siRNAs for 32 hrs. 157 million reads were generated from triplicate samples of the control group; 151 million reads were generated from triplicate samples of the SRA knockdown group. Six genes were identified as significantly changed in the expression levels with the cutoff of q value ≤ 0.05, fold change ≤ 0.5 or ≥ 2, and reads per kilobase per million mapped reads (RPKM) ≥ 1. However, except for SRA itself, the other five genes were shown by real-time PCR to be only affected by one siRNA in the SRA siRNA pool. Further analysis of this dataset with different cuttoff setting may reveal true SRA-regulated genes in MCF-7.
Project description:We performed Chromatin Isolation by RNA Purification (ChIRP) of SRA by high-throughput sequencing in K562 cell line. We find that SRA occupied genome-wide including alpha- and beta-globin loci.
Project description:The sequence read archive (SRA) contains over 52 terabases or 482 billion reads from Drosophila melanogaster (as of June 2018). These data are massively underused by the community and include 14,423 RNA-Seq samples, that is roughly 7 times the size of modENCODE. Currently the major challenge is finding high quality datasets that are suitable for inclusion in new studies. To help the community overcome this hurdle, we re-processed all D. melanogaster RNA-Seq SRA experiments (SRXs) using an identical workflow. This workflow uses a data driven approach to identify technical metadata (i.e., strandedness and layout) for each sample in order to optimize mapping parameters. The workflow generates QC metrics, coverage tracks based on the dm6 assembly, and calculates gene level, junction level, and intergenic counts against FlyBase r6.11. This resource will allow any researcher to visualize browser tracks for any publicly available dataset, quickly identify high quality data sets for use in their own research, and download identically processed counts tables. There is a treasure trove of underused data sitting in the SRA and this work addresses the first challenge to make data integration a common laboratory practice.
Project description:In order to test the global effects of CpG island-centered gene regulation on global gene expression profile, pA+ RNA-seq data of diverse tissues and cell lines were gathered and profiled. All available mouse poly-A positive RNA-seq data (3,818 samples) were summarized and downloaded at May, 5th, 2015. Among them, excluding single cell RNA-seq or experiments whose expression verified gene counts are small (less than 5,000 genes with RPKM 0.5 or higher), 1,524 high quality RNA-seq data were used. Raw data were downloaded from Sequence Read Archive (SRA) in National Center for Biotechnology Information (NCBI) database. FASTQ files were extracted with the SRA Toolkit version 2.5.5 and aligned using STAR 2.4.2 onto the mouse and human genome (mm9 and hg19, respectively). Gene expression was calculated as RPKM values using rpkmforgenes.py (Ramsköld et al., 2009).