Project description:This study profiles RNA:DNA hybrid formation in human and mouse cell lines. DRIPc-seq (strand-specific R-loop mapping) was performed on human NT2 cells and mouse 3T3 cells. DRIP-seq (R-loop mapping) was performed on human NT2 and K562 and mouse E14 and 3T3 cell lines. MethylC-seq and RNA-seq were performed on NT2.
Project description:Strand asymmetry in the distribution of guanines and cytosines, measured by GC skew, predisposes DNA sequences towards R-loop formation upon transcription. Previous work revealed that GC skew and R-loop formation associate with a core set of unmethylated CpG island (CGI) promoters in the human genome. Here, we show that GC skew can distinguish four classes of promoters, including three types of CGI promoters, each associated with unique epigenetic and gene ontology signatures. In particular, we identify a strong and a weak class of CGI promoters and show that these loci are enriched in distinct chromosomal territories reflecting the intrinsic strength of their protection against DNA methylation. Interestingly, we show that strong CGI promoters are depleted from the X chromosome while weak CGIs are enriched, a property consistent with the acquisition of DNA methylation during dosage compensation. Furthermore, we identify a third class of CGI promoters based on its unique GC skew profile and show that this gene set is enriched for Polycomb group targets. Lastly, we show that nearly 2,000 genes harbor GC skew at their 3’ ends and that these genes are preferentially located in gene-dense regions and tend to be closely arranged. Genomic profiling of R-loops accordingly showed that a large proportion of genes with terminal GC skew form R-loops at their 3’-ends, consistent with a role for these structures in permitting efficient transcription termination. Altogether, we show that GC skew and R-loop formation offer significant insights into the epigenetic regulation, genomic organization, and function of human genes. DRIP-seq was performed on genomic DNA extracted from human pluripotent Ntera2 cells. The DNA was either fragmented using HindIII, EcoRI, BsrGI, XbaI and SspI (DRIP-seq 1) or BamHI, NcoI, ApaLI, NheI and PvuII (DRIP-seq 2, two technical replicates). Input DNA was also fragmented with each restriction enzyme cocktail and sequenced alongside.
Project description:Determining the role of DDX17 in the formation of DNA:RNA-hybrids around active DNA double-strand breaks (DSBs) using DRIP-seq in the damaged induced via AsiSI (DIvA) cell system that induced DSBs at known genomic loci in response to hydroxytamoxifen (OHT) treatment via and AsiSI enzyme fused to an oestrogen receptor. Sequencing was done using either control or DDX17 siRNA, and mock or 4 hours 300nM OHT treatment. Paired-end 150 cycles was completed on an Illumina NextSeq 500 and library prep was completed using the NEB NEBNext Ultra II library prep kit.
Project description:Distribution of R-loops on genomic sites was studied for exponentially growing Escherichia coli in different conditions using strand-specific DRIP-Seq with S9.6 antibodies.
Project description:To investigate the distribution of R-loop formation, we peformed R-loop mapping analysis using S9.6 antibody-based DRIP-seq in K562 cells (wild type and SF3B1K700E mutant) at 4 days after mutant allele expression We then performed metaplot and peak-based analysis using data obtained from DRIP-seq
Project description:Experiment to obtain the genome-wide distribution of DNA:RNA hybrid prone loci in Saccharomyces cerevisiae by DNA:RNA immunoprecipitation and tiling microarray (DRIP-chip). Samples: wild type, Rnase H deletion mutant, hpr1 deletion mutant, sen1-1 temperature sensitive mutant.