Project description:Analysis of Histone H3 Lysine 4 mono-, di- and trimethyl and the boundary protein CTCF in CD4+CD25+CD45RA+ regulatory T-cells and conventional CD4+CD25- T-cells. To investigate regulatory functions or potential new transcription start sites in Treg and Tconv cells, we investigated the associated histone modifications. Mono- and dimethylation of histone 3 lysin 4 (H3K4) were previously shown to mark enhancer regions, whereas H3K4 trimethylation generally associates with transcription start sites. At imprinted loci, binding of the insulator protein CTCF, which restricts or directs enhancer-promoter interactions, is often regulated by DNA-methylation. Therefore we performed ChIP-on-chip experiments (chromatin immunoprecipitation followed by microarray hybridization; samples were amplified with ligation mediated PCR [see label protocol for the procedure] prior to labeling) for mono- di- and trimethylation of histone 3 lysin 4 and of CTCF in expanded Treg and Tconv cells. Keywords: ChIP-on-chip ChIP-on-chip experiments for H3K4 mono-, di- and trimethyl and CTCF in CD4+CD25+CD45RA+ regulatory T-cells and conventional CD4+CD25- T-cells were co-hybridizied with the input. Three biologiacal replicates (rep1-3) were performed for every histone mark, two CTCF (rep1 and rep2).
Project description:Analysis of Histone H3 Lysine 4 mono-, di- and trimethyl and the boundary protein CTCF in CD4+CD25+CD45RA+ regulatory T-cells and conventional CD4+CD25- T-cells. To investigate regulatory functions or potential new transcription start sites in Treg and Tconv cells, we investigated the associated histone modifications. Mono- and dimethylation of histone 3 lysin 4 (H3K4) were previously shown to mark enhancer regions, whereas H3K4 trimethylation generally associates with transcription start sites. At imprinted loci, binding of the insulator protein CTCF, which restricts or directs enhancer-promoter interactions, is often regulated by DNA-methylation. Therefore we performed ChIP-on-chip experiments (chromatin immunoprecipitation followed by microarray hybridization; samples were amplified with ligation mediated PCR [see label protocol for the procedure] prior to labeling) for mono- di- and trimethylation of histone 3 lysin 4 and of CTCF in expanded Treg and Tconv cells. Keywords: ChIP-on-chip
Project description:Histone H3K4 methylation is a feature of meiotic recombination hotspots shared by many organisms including plants and mammals. Meiotic recombination is initiated by programmed double strand break (DSB) formation that in budding yeast is directed in gene promoters by histone H3K4 di/trimethylation. This histone modification is indeed recognized by Spp1, a PHD-finger containing protein that belongs to the conserved histone H3K4 methyltransferase Set1 complex. During meiosis, Spp1 binds H3K4me and recruits a DSB protein, Mer2, to promote DSB formation close to gene promoters. How Set1C and Mer2 related functions of Spp1 are connected is not clear.
Project description:To understand the role of LSD1 in regulating histone H3K4 methylation status, ChIP-seq analyse of mono- and di-methylated H3K4 in LSD1-KD HEL cells were performed. The analyses revealed demethylation of H3K4me1 and H3K4me2 by LSD1 at regulatory regions including CEBPA gene enhancer.
Project description:Enhancers act to regulate cell type specific gene expression by facilitating the transcription of target genes. In mammalian cells active or primed enhancers are commonly marked by monomethylation of Histone H3 at lysine 4 (H3K4me1) in a cell-type specific manner. Whether and how this histone modification regulates enhancer-dependent transcription programs in mammals has been unclear. In the present study, we conducted SILAC Mass-spec experiments with mono-nucleosomes and identified multiple H3K4me1 associated proteins, including proteins involved in chromatin remodeling. We demonstrate that H3K4me1 augments the association of the chromatin remodeling complex BAF to enhancers in vivo. Furthermore we show that in vitro, H3K4me1 nucleosomes are more efficiently remodeled by the BAF complex. Crystal structures of a BAF component BAF45c further reveal that monomethylation, but not trimethylation, is accommodated in this protein’s H3K4 binding site. Our results suggest that H3K4me1 plays an active role at enhancers by facilitating the binding of the BAF complex and possibly other chromatin regulators.
Project description:These ChIP-seq data files are part of a study where a comparison was made between the change in transcription and H3K4 mono-, di-, and tri-methylation levels in the Arabidopsis thaliana genome when plants are subjected to water deficit stress. Keywords: stress response, histone modification
Project description:In yeast and other eukaryotes, the histone methyltransferase Set1 mediates methylation of lysine 4 on histone H3 (H3K4me). This modification marks the 5' end of transcribed genes in a 5' to 3' tri- to di- to monomethyl gradient, and promotes association of chromatin remodeling enzymes that regulate transcription. In a screen to identify factors that control the distinct H3K4 methylation states, we identified Ctk1, the serine 2 C-terminal domain (CTD) kinase for RNA polymerase II (RNAP II). We found that CTK1 deletion nearly abolished H3K4 monomethylation, yet caused a significant increase in H3K4 di- and trimethylation. Both on individual genes and genome-wide, the loss of CTK1 disrupted the H3K4 methylation patterns normally observed. H3K4me2 and H3K4me3 spread 3' into the body of genes, while H3K4 monomethylation was diminished. These effects were dependent on the catalytic activity of Ctk1, but are independent of Set2-mediated H3K36 methylation. Furthermore, these effects are not due to spurious transcription initiation in the body of genes, changes in RNAP II occupancy, changes in serine 5 CTD phosphorylation patterns, or to ‘transcriptional stress’. These data show that Ctk1 acts to restrict the spread of H3K4 methylation through a mechanism that is independent of a general transcription defect. The evidence presented indicates that Ctk1 controls the maintenance of suppressive chromatin in the coding regions of genes by both promoting H3K36 methylation, which leads to histone hypoacetylation, and by preventing the 3' spread of H3K4 trimethylation, a mark associated with chromatin remodeling at the 5' end of genes. Keywords: ChIP-chip
Project description:This work uncovers a novel and biologically significant mechanism that directly connects nutrient availability to histone modifications and gene transcription. We report that glycolysis promotes histone H3K4 trimethylation (H3K4me3) by activating Tpk2, a catalytic subunit of protein kinase A (PKA) via the Ras-cyclic AMP (cAMP) pathway. Glucose-activated PKA (Tpk2) inhibits Jhd2-catalyzed H3K4 demethylation by phosphorylating Jhd2 at serine 321 and serine 340. In addition, Tpk2- catalyzed Jhd2 phosphorylation promotes H3K14ac by preventing the binding of Rpd3 at chromatin.