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.
