Project description:Histone H3 lysine 9 (H3K9) methylation is a central epigenetic modification that defines heterochromatin from unicellular to multicellular organisms. In mammalian cells, H3K9 methylation can be catalyzed by at least six distinct SET domain enzymes: Suv39h1/Suv39h2, Eset1/Eset2 and G9a/Glp. We used mouse embryonic fibroblasts (MEFs) with a conditional mutation for Eset1 and introduced progressive deletions for the other SET domain genes by CRISPR/Cas9 technology. Compound mutant MEFs for all 6 SET domain methyltransferase (KMT) genes lack all H3K9 methylation states, derepress nearly all families of repeat elements and display genomic instabilities. Strikingly, the 6KO H3K9 KMT MEFs no longer maintain heterochromatin organization and have lost electron-dense heterochromatin. This is the first analysis of H3K9 methylation deficient mammalian chromatin and reveals a crucial function for H3K9 methylation in protecting heterochromatin organization and genome integrity.
Project description:Methylation of histone 3 on lysine 79 (H3K79) is broadly associated with active gene expression in eukaryotes, and the H3K79 methyltransferase DOT1L is indispensable for specific leukemia subtypes like those with MLL-translocations. We found that suppression of the histone deacetylase SIRT1 rescued MLL-AF9 leukemia cells from their dependence on DOT1L. We show that upon DOT1L inhibition, SIRT1 is required for the acquisition of a repressive chromatin state consistent with facultative heterochromatin around MLL-AF9 target genes in leukemia and other genes possess an H3K79me2(hi), H3K9ac(hi), H3K9me2(low) histone modification profile in normal hematopoietic stem and progenitor cells. Examination of histone modifications via ChIP-seq in three human cancer cell lines.
Project description:Methylation of histone 3 on lysine 79 (H3K79) is broadly associated with active gene expression in eukaryotes, and the H3K79 methyltransferase DOT1L is indispensable for specific leukemia subtypes like those with MLL-translocations. We found that suppression of the histone deacetylase SIRT1 rescued MLL-AF9 leukemia cells from their dependence on DOT1L. We show that upon DOT1L inhibition, SIRT1 is required for the acquisition of a repressive chromatin state consistent with facultative heterochromatin around MLL-AF9 target genes in leukemia and other genes possess an H3K79me2(hi), H3K9ac(hi), H3K9me2(low) histone modification profile in normal hematopoietic stem and progenitor cells. Examination of gene expression dynamics with and without drug treatment and RNA interference.
Project description:Methylation of histone 3 on lysine 79 (H3K79) is broadly associated with active gene expression in eukaryotes, and the H3K79 methyltransferase DOT1L is indispensable for specific leukemia subtypes like those with MLL-translocations. We found that suppression of the histone deacetylase SIRT1 rescued MLL-AF9 leukemia cells from their dependence on DOT1L. We show that upon DOT1L inhibition, SIRT1 is required for the acquisition of a repressive chromatin state consistent with facultative heterochromatin around MLL-AF9 target genes in leukemia and other genes possess an H3K79me2(hi), H3K9ac(hi), H3K9me2(low) histone modification profile in normal hematopoietic stem and progenitor cells. Examination of histone modifications and a chromatin modifier with and without drug treatment and RNA interference.
Project description:Methylation of histone 3 on lysine 79 (H3K79) is broadly associated with active gene expression in eukaryotes, and the H3K79 methyltransferase DOT1L is indispensable for specific leukemia subtypes like those with MLL-translocations. We found that suppression of the histone deacetylase SIRT1 rescued MLL-AF9 leukemia cells from their dependence on DOT1L. We show that upon DOT1L inhibition, SIRT1 is required for the acquisition of a repressive chromatin state consistent with facultative heterochromatin around MLL-AF9 target genes in leukemia and other genes possess an H3K79me2(hi), H3K9ac(hi), H3K9me2(low) histone modification profile in normal hematopoietic stem and progenitor cells. Examination of histone modifications and a chromatin modifier with and without drug treatment and RNA interference.
Project description:Methylation of histone 3 on lysine 79 (H3K79) is broadly associated with active gene expression in eukaryotes, and the H3K79 methyltransferase DOT1L is indispensable for specific leukemia subtypes like those with MLL-translocations. We found that suppression of the histone deacetylase SIRT1 rescued MLL-AF9 leukemia cells from their dependence on DOT1L. We show that upon DOT1L inhibition, SIRT1 is required for the acquisition of a repressive chromatin state consistent with facultative heterochromatin around MLL-AF9 target genes in leukemia and other genes possess an H3K79me2(hi), H3K9ac(hi), H3K9me2(low) histone modification profile in normal hematopoietic stem and progenitor cells.