Project description:We investigated the RNAPII and γH2AX occupancy genome wide by ChIP-Seq in MLL2 F/F and FC/FC80 MEF cells. We found that a week after MLL2 excision (FC/FC cells), a group of genes present higher levels of γH2AX and RNAPII near the TSS, as compared to the control (F/F cells). H3K4Me1, H3K4M2 and H3K4Me3 levels near the TSS were also studied.
Project description:We investigated the RNAPII and γH2AX occupancy genome wide by ChIP-Seq in MLL2 F/F and FC/FC80 MEF cells. We found that a week after MLL2 excision (FC/FC cells), a group of genes present higher levels of γH2AX and RNAPII near the TSS, as compared to the control (F/F cells). H3K4Me1, H3K4M2 and H3K4Me3 levels near the TSS were also studied. There is a total of 52 samples. 3 independent replicates for each experiment were performed. H3, H2AX and IgG ChIPs were used for normalisation or as controls.The experiments were performed using immortalised mouse embryonic fibroblasts (MEF) in which both MLL2 alleles were targeted by the loxp system (F/F cells). Tamoxifen treatment of the F/F cells for 24 hours results in the excision of both MLL2 alleles (FC/FC cells).
Project description:Global Run-On has been performed in MLL2 F/F and FC/FC MEF cells. The aim of the experiment is to test how the lack of MLL2 affects nascent RNA transcription. Four samples were analyzed - 2 independent replicates. The experiments were performed using immortalized mouse embryonic fibroblasts (MEF) in which both MLL2 alleles were targeted by the loxp system (F/F cells). Tamoxifen treatment of the F/F cells for 24 hours results in the excision of both MLL2 alleles (FC/FC cells).
Project description:Global Run-On has been performed in MLL2 F/F and FC/FC MEF cells. The aim of the experiment is to test how the lack of MLL2 affects nascent RNA transcription.
Project description:Trimethylation of histone H3 lysine 4 (H3K4me3) is associated with transcriptional start sites and proposed to regulate transcription initiation. However, redundant functions of the H3K4 SET1/COMPASS methyltransferase complexes complicate elucidation of the specific role of H3K4me3 in transcriptional regulation. Here, by using mouse embryonic stem cells (mESCs) as a model system, we show that acute ablation of shared subunits of the SET1/COMPASS complexes leads to complete loss of all H3K4 methylation. H3K4me3 turnover occurs more rapidly than H3K4me1 and H3K4me2 and is dependent on KDM5 demethylases. Surprisingly, acute loss of H3K4me3 does not have detectable effects on transcriptional initiation but leads to a widespread decrease in transcriptional output, an increase in RNA polymerase II (RNAPII) pausing and slower elongation. Notably, we show that H3K4me3 is required for the recruitment of the Integrator Complex Subunit 11 (INTS11), which is essential for the eviction of paused RNAPII and transcriptional elongation. Thus, our study demonstrates a distinct role for H3K4me3 in transcriptional pause-release and elongation rather than transcriptional initiation.
Project description:Promoters of many developmentally regulated genes, in the embryonic stem cell state, have a bivalent mark of H3K27me3 and H3K4me3, proposed to confer precise temporal activation upon differentiation. Although Polycomb repressive complex 2 is known to implement H3K27 trimethylation, the COMPASS family member responsible for H3K4me3 at bivalently marked promoters was previously unknown. Here, we identify Mll2 (KMT2b) as the enzyme catalyzing H3K4 trimethylation at bivalently marked promoters in embryonic stem cells. Although H3K4me3 at bivalent genes is proposed to prime future activation, we detected no substantial defect in rapid transcriptional induction after retinoic acid treatment in Mll2-depleted cells. Our identification of the Mll2 complex as the COMPASS family member responsible for H3K4me3 marking at bivalent promoters provides an opportunity to reevaluate and experimentally test models for the function of bivalency in the embryonic stem cell state and in differentiation. ChIP-Seq in mouse embryonic stem (mES) cells for MLL2. ChIP-seq of H3K4me1, H3K4me3 and H3K27me3 for mES cells with RNAi against MLL2(shMLL2) and control (shGFP). ChIP-seq of H3K4me3 in mES cells with RNAi against MLL3 (shMLL3). RNA-seq of mES cells with RNAi against MLL2 and control (shGFP). RNA-seq of control mES cells (shGFP) or MLL2 RNAi mES cells (shMLL2) induced with RA for 6h and 12h.
Project description:Trimethylation of histone H3 lysine 4 (H3K4me3) is associated with transcriptional start sites and proposed to regulate transcription initiation. However, redundant functions of the H3K4 SET1/COMPASS methyltransferase complexes complicate elucidation of the specific role of H3K4me3 in transcriptional regulation. Here, we show that acute ablation of shared subunits of the SET1/COMPASS complexes leads to complete loss of all H3K4 methylation. H3K4me3 turnover occurs more rapidly than H3K4me1 and H3K4me2 and is dependent on KDM5 demethylases. Surprisingly, acute loss of H3K4me3 does not have detectable effects on transcriptional initiation but leads to a widespread decrease in transcriptional output, an increase in RNA polymerase II (RNAPII) pausing and slower elongation. Our study demonstrates a distinct role for H3K4me3 in transcriptional pause-release and elongation rather than transcriptional initiation.
Project description:Genome-wide mapping of H3K4me1, H3K4me3 and H3K27ac in KP and DK ChIP-seq for H3K4me1, H3K4me3 and H3K27ac in KP and DK p63 profiling of DK through ChIP-seq