Project description:In eukaryotic cells, DNA is tightly packed in the nucleus in chromatin which has histones as its main protein component. Histones are subject to a large number of distinct post-translational modifications, whose sequential or combinatorial action affects genome function. Here, we report the identification of acetylation at lysine 36 in histone H3 (H3K36ac) as a modification in Arabidopsis thaliana. H3K36ac was found to be an evolutionary conserved modification in seed plants. It is highly enriched in euchromatin and very low in heterochromatin. Genome-wide ChIP-seq experiments revealed that H3K36ac is generally found at the 5â?? end of genes. Independently of gene length, H3K36ac covers about 500 bp, about two to three nucleosomes, immediately downstream of the transcriptional start. H3K36ac overlaps with H3K4me3 and the H2A.Z histone variant. The histone acetyl transferase GCN5 and the histone deacetylase HDA19 are required for normal steady state levels of H3K36ac in plants. There is negative crosstalk between H3K36ac and H3K36me3, mediated by the histone methyl transferase SDG8 and GCN5. H3K36ac levels are associated with transcriptional activity but show no linear relation. Instead, H3K36ac is a binary indicator of transcription Characterization of the genome-wide distribution of H3K36ac using ChIP-seq. Analysis of the mechanistic crosstalk in the deposition of acetylation and methylation at H3K36 by ChIP-seq of H3K36ac and H3K36me3 in sdg8-2 and gcn5-1, respectively.
Project description:Histone lysine (K) acetylation is a major mechanism by which cells regulate the structure and function of chromatin, and new sites of acetylation continue to be discovered. Here we identify and characterize histone H3K36 acetylation (H3K36ac). By mass spectrometric analysis of H3 purified from Tetrahymena thermophila and S. cerevisiae (yeast), we find that H3K36 is acetylated in addition to being methylated. Using an antibody specific to H3K36ac, we show that this modification is conserved in mammals. In yeast, genome-wide ChIP-chip experiments show that H3K36ac is localized predominantly to the promoters of RNA polymerase II-transcribed genes, a pattern mutually exclusive to that of H3K36 methylation. The pattern of H3K36ac localization is similar to that of other sites of H3 acetylation, including H3K9ac and H3K14ac. Using histone acetyltransferase complexes purified from yeast, we show that the Gcn5-containing SAGA complex specifically acetylates H3K36 in vitro. Deletion of GCN5 completely abolishes H3K36ac in vivo. The regulation of H3K36ac by Gcn5 suggests a function for this modification in transcription. These data expand our knowledge of the genomic targets of Gcn5, show H3K36ac is highly conserved, and raise the intriguing possibility that the transition between H3K36ac and H3K36me acts as a switch in chromatin function along transcription units. This SuperSeries is composed of the SubSeries listed below.
Project description:In eukaryotic cells, DNA is tightly packed in the nucleus in chromatin which has histones as its main protein component. Histones are subject to a large number of distinct post-translational modifications, whose sequential or combinatorial action affects genome function. Here, we report the identification of acetylation at lysine 36 in histone H3 (H3K36ac) as a modification in Arabidopsis thaliana. H3K36ac was found to be an evolutionary conserved modification in seed plants. It is highly enriched in euchromatin and very low in heterochromatin. Genome-wide ChIP-seq experiments revealed that H3K36ac is generally found at the 5’ end of genes. Independently of gene length, H3K36ac covers about 500 bp, about two to three nucleosomes, immediately downstream of the transcriptional start. H3K36ac overlaps with H3K4me3 and the H2A.Z histone variant. The histone acetyl transferase GCN5 and the histone deacetylase HDA19 are required for normal steady state levels of H3K36ac in plants. There is negative crosstalk between H3K36ac and H3K36me3, mediated by the histone methyl transferase SDG8 and GCN5. H3K36ac levels are associated with transcriptional activity but show no linear relation. Instead, H3K36ac is a binary indicator of transcription
Project description:ChIP-chip experiments were done to analyze the global distribution of H3K36Ac or H3K9K14Ac in yeast compared to H3 distribution Keywords: ChIP-chip