Project description:During development, changes in gene transcription are accompanied by changes in chromatin modification but the order and causality of events often remain unclear. Here we address this question using X-chromosome inactivation (XCI), which entails chromosome-wide gene silencing and heterochromatin formation. We initiate XCI in female, mouse embryonic stem cells by inducing Xist expression and monitor subsequent changes in transcription and chromatin modification by allele-specific TTseq and ChIPseq respectively. An unprecedented temporal resolution has enabled us to define early alterations in chromatin that are induced upon Xist RNA coating. Xist-induced repression begins with histone deacetylation, which involves the histone deacetylase HDAC3 and occurs before efficient loss of H3K4me3 and H3K4me1 modifications. Polycomb-associated repressive histone marks accumulate rapidly, starting with PRC1-associated H2AK119Ub and followed by PRC2-associated H3K27me3. However, polycomb accumulates initially at large premarked domains, some of which correspond to Xist entry sites, and then spreads into genes. We also show that spreading can only ensue when transcriptional silencing has occurred. These results establish a detailed epigenomic time course for XCI and reveal a hierarchy of events with chromatin playing an important role in transcriptional silencing of the X chromosome.
Project description:To understand the role of DPPA2 in epigenetic memory during X-Chromosome reactivation (XCR) we employed inducible Xist hybrid female embryonic stem cell line (TX1072, hybrid Bl6/Cast). Wild type or Dppa2 knockout TX1072 cells were cultured, in three or two independent biological replicates, respectively, in presence of DOX (1ug/ml) for 6 days to induce Xist overexpression and X-Chomosome inactivation (XCI) on the Bl6 allele. DOX was then washed out to silence Xist and XCR was followed in a time-series at 1, 3 or 7 days after DOX removal. Cell pellets were harvested at the following timepoints: -DOX, +DOX, 1d D-wo, 3d D-wo and 7d D-wo. RNA was extracted and 250 ng used for PolyA mRNA library preparation and Next generation sequencing.
Project description:A strain harboring two copies of RAP1 is used for a competition-ChIP experiment. One copy of RAP1 is expressed from the endogenous RAP1 promoter and a c-terminal 3X FLAG epitiope tag and the other is expressed from a weakened Galactose inducible promoter and a c-terminal 9X MYC tag. Following induction by 2% galactose Rap1-Myc and Rap1-Flag levels are determined genome wide using ChIP-chip. Time Course ChIP-ChIP experiment, Rap1-Flag IP and Rap1-Myc IP. 13 Time Points (0, 10, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210, 240 Minutes) 2 Biological Replicates. Total Rap1 Occupancy at times 0 and 60 minutes in the time course; 2 Biological Replicates. mRNA expression levels at times 0 and 60 minutes in the time course; 2 biological Replicates. ChIPs comparing the occupancy of Rap1 in a strain containing two copies of Rap1, one with a Flag tag and one with a Myc tag, and expressed from an identical promoter.
Project description:A strain harboring two copies of RAP1 is used for a competition-ChIP experiment. One copy of RAP1 is expressed from the endogenous RAP1 promoter and a c-terminal 3X FLAG epitiope tag and the other is expressed from a weakened Galactose inducible promoter and a c-terminal 9X MYC tag. Following induction by 2% galactose Rap1-Myc and Rap1-Flag levels are determined genome wide using ChIP-chip. Time Course ChIP-ChIP experiment, Rap1-Flag IP and Rap1-Myc IP. 10 Time Points (0,10,20,30,40,50,60,90,120,150 Minutes) 2 Biological Replicates. Total Rap1 Occupancy at times 0 and 60 minutes in the time course; 2 Biological Replicates. mRNA expression levels at times 0 and 60 minutes in the time course; 2 biological Replicates.
Project description:Murine ES cell gene expression before RA induction are used to compare gene expression for time-points of 2, 4, 6hrs post-induction. KH2 ES Cell RA Differentiation Time-course
Project description:Murine ES cell gene expression before RA induction are used to compare gene expression for time-points of 8, 12, 16, 24, 36, 48, 60 and 72 hours post-induction. KH2 ES Cell RA Differentiation Time-course
Project description:ChIPseq on H3K27ac, H4ac, H3K9ac, H3K4me3, H3K4me1, H3K27me3 and H2AK119Ub on TX1072 WT, Hdac3-/-, and ChIP targeting FLAG on Hdac3-AID-FLAG cell lines, at different time of Dox induction.