Project description:This SuperSeries is composed of the following subset Series: GSE18261: Expression analysis on Mll1+/+ and Mll1-/- MEFs GSE18262: ChIP-chip with antibodies for histone 3 lysine 4 trimethylation and histone 3 in Mll1+/+ and Mll1-/- MEFs GSE18263: ChIP-chip with antibodies for histone 3 lysine 4 trimethylation in Mll3+/+ and Mll3-/- MEFs and Ptip+/+ and Ptip-/- MEFs GSE18264: ChIP-chip with antibodies for histone 3 lysine 4 trimethylation, histone 3, and PolII in Mll1+/+ and Mll1-/- MEFs Refer to individual Series
Project description:Global analysis of H3K4 methylation defines MLL family member targets and points to a role for MLL1-mediated H3K4 methylation in the regulation of transcriptional initiation by RNA polymerase II A common landmark of activated genes is the presence of trimethylation on lysine 4 of histone H3 (H3K4) at promoter regions. The Set1/COMPASS was the founding member and the only H3K4 methylases in S. cerevisiae, however, in mammals at least six H3K4 methylases Set1A/B and MLL1-4 are found in COMPASS-like complexes capable of methylating H3K4. To gain further insight into the different roles and functional targets for the H3K4 methylases, we have undertaken a genome-wide analysis of H3K4 methylation pattern in wild-type Mll1+/+ and Mll1-/- mouse fibroblasts (MEFs). We found that Mll1 is required for the H3K4 trimethylation of less than 5% of promoters carrying this modification. Many of these genes, which include developmental regulators such as Hox genes show decreased levels of RNA polymerase II recruitment and expression concomitant with the loss of H3K4 methylation. Although Mll1 is only required for the methylation of a subset of Hox genes, Menin, a component of the Mll1 and Mll2 complexes, is required for the overwhelming majority of H3K4 methylation at Hox loci. However, the loss of MLL3/4 and/or the Set1 complexes have little to no effect on the Hox loci H3K4 methylation or expression levels in these MEFs. Together these data provide insight into redundancy and specialization of COMPASS-like complexes in mammals and provide evidence on a possible role for Mll1-mediated H3K4 methylation in the regulation of transcriptional initiation. Chromatin Immunoprecipitation was performed with antibodies for histone 3 lysine 4 trimethylation, histone 3, and PolII in Mll1+/+ and Mll1-/- mouse embryonic fibroblasts. DNA was hybridized to a custom Agilent tiling array (4x44k format) that covers three of the hox regions (A,B,D) and a collection of other genes.
Project description:Global analysis of H3K4 methylation defines MLL family member targets and points to a role for MLL1-mediated H3K4 methylation in the regulation of transcriptional initiation by RNA polymerase II A common landmark of activated genes is the presence of trimethylation on lysine 4 of histone H3 (H3K4) at promoter regions. The Set1/COMPASS was the founding member and the only H3K4 methylases in S. cerevisiae, however, in mammals at least six H3K4 methylases Set1A/B and MLL1-4 are found in COMPASS-like complexes capable of methylating H3K4. To gain further insight into the different roles and functional targets for the H3K4 methylases, we have undertaken a genome-wide analysis of H3K4 methylation pattern in wild-type Mll1+/+ and Mll1-/- mouse fibroblasts (MEFs). We found that Mll1 is required for the H3K4 trimethylation of less than 5% of promoters carrying this modification. Many of these genes, which include developmental regulators such as Hox genes show decreased levels of RNA polymerase II recruitment and expression concomitant with the loss of H3K4 methylation. Although Mll1 is only required for the methylation of a subset of Hox genes, Menin, a component of the Mll1 and Mll2 complexes, is required for the overwhelming majority of H3K4 methylation at Hox loci. However, the loss of MLL3/4 and/or the Set1 complexes have little to no effect on the Hox loci H3K4 methylation or expression levels in these MEFs. Together these data provide insight into redundancy and specialization of COMPASS-like complexes in mammals and provide evidence on a possible role for Mll1-mediated H3K4 methylation in the regulation of transcriptional initiation. Expression arrays were done with Mll1+/+ and Mll1-/- mouse embryonic fibroblasts. Four replicates were done (dyes were swapped). DNA was hybridized to Agilent Mouse Whole Genome Expression Arrays (4x44k).
Project description:An experiment was performed to understand its role in cell type specification, we have determined the human genomic binding sites of MLL1. MLL1 localizes with Pol II to the 5' end of actively transcribed genes, where histone H3 lysine 4 (H3-K4) trimethylation occurs. The ability of MLL1 to serve as a start site-specific global transcriptional regulator and to participate in larger chromatin domains at the Hox genes reveals the dual roles MLL1 plays in maintenance of cellular identity.
Project description:Despite correlations between histone methyltransferase (HMT) activity and gene regulation, direct evidence that HMT activity is responsible for gene activation is sparse. We address the role of the HMT activity for MLL1, a histone H3 lysine 4 (H3K4) methyltransferase critical for maintaining hematopoietic stem cells (HSCs). Here we show that the SET domain and thus HMT activity of MLL1 is dispensable for maintaining HSCs and for supporting leukemogenesis driven by the MLL-AF9 fusion oncoprotein. Upon Mll1 deletion, histone H4 lysine 16 (H4K16) acetylation was selectively depleted at MLL1 target genes in conjunction with reduced transcription. Surprisingly, inhibition of SIRT1 was sufficient to prevent the loss of H4K16 acetylation and the reduction in MLL1 target gene expression. Thus, recruited MOF activity, and not the intrinsic HMT activity of MLL1, is central for the maintenance of HSC target genes. In addition, this work reveals a role for SIRT1 in opposing MLL1 function. 11 Samples, 5 controls and 5 KOs with antibodies H3K4me1, H3K4me3, and H3K27Ac. One input Sample.
Project description:Global analysis of H3K4 methylation defines MLL family member targets and points to a role for MLL1-mediated H3K4 methylation in the regulation of transcriptional initiation by RNA polymerase II A common landmark of activated genes is the presence of trimethylation on lysine 4 of histone H3 (H3K4) at promoter regions. The Set1/COMPASS was the founding member and the only H3K4 methylases in S. cerevisiae, however, in mammals at least six H3K4 methylases Set1A/B and MLL1-4 are found in COMPASS-like complexes capable of methylating H3K4. To gain further insight into the different roles and functional targets for the H3K4 methylases, we have undertaken a genome-wide analysis of H3K4 methylation pattern in wild-type Mll1+/+ and Mll1-/- mouse fibroblasts (MEFs). We found that Mll1 is required for the H3K4 trimethylation of less than 5% of promoters carrying this modification. Many of these genes, which include developmental regulators such as Hox genes show decreased levels of RNA polymerase II recruitment and expression concomitant with the loss of H3K4 methylation. Although Mll1 is only required for the methylation of a subset of Hox genes, Menin, a component of the Mll1 and Mll2 complexes, is required for the overwhelming majority of H3K4 methylation at Hox loci. However, the loss of MLL3/4 and/or the Set1 complexes have little to no effect on the Hox loci H3K4 methylation or expression levels in these MEFs. Together these data provide insight into redundancy and specialization of COMPASS-like complexes in mammals and provide evidence on a possible role for Mll1-mediated H3K4 methylation in the regulation of transcriptional initiation.
Project description:Global analysis of H3K4 methylation defines MLL family member targets and points to a role for MLL1-mediated H3K4 methylation in the regulation of transcriptional initiation by RNA polymerase II A common landmark of activated genes is the presence of trimethylation on lysine 4 of histone H3 (H3K4) at promoter regions. The Set1/COMPASS was the founding member and the only H3K4 methylases in S. cerevisiae, however, in mammals at least six H3K4 methylases Set1A/B and MLL1-4 are found in COMPASS-like complexes capable of methylating H3K4. To gain further insight into the different roles and functional targets for the H3K4 methylases, we have undertaken a genome-wide analysis of H3K4 methylation pattern in wild-type Mll1+/+ and Mll1-/- mouse fibroblasts (MEFs). We found that Mll1 is required for the H3K4 trimethylation of less than 5% of promoters carrying this modification. Many of these genes, which include developmental regulators such as Hox genes show decreased levels of RNA polymerase II recruitment and expression concomitant with the loss of H3K4 methylation. Although Mll1 is only required for the methylation of a subset of Hox genes, Menin, a component of the Mll1 and Mll2 complexes, is required for the overwhelming majority of H3K4 methylation at Hox loci. However, the loss of MLL3/4 and/or the Set1 complexes have little to no effect on the Hox loci H3K4 methylation or expression levels in these MEFs. Together these data provide insight into redundancy and specialization of COMPASS-like complexes in mammals and provide evidence on a possible role for Mll1-mediated H3K4 methylation in the regulation of transcriptional initiation.