Mitotic H3K9 acetylation patterns are controlled by phase-specific activity of the histone deacetylases HDAC2, 3 and SIRT1

Histone acetylation play a fundamental role in many biological processes. H3K9ac is tightly linked to active transcription, and enriched in promoters, enhancers and insulators. During mitosis H3k9ac levels are reduced, and the mechanism of this reduction is not clear. Here, we used small molecules inhibitors of histone deacetylases and evaluated by immunofluorescence and western blots the involvement of each of the targeted enzymes in regulating H3K9ac during prophase, metaphase, anaphase, telophase and cytokinesis. We identified three histone deacetylases, HDAC2, HDAC3 and SIRT1, as modulators of H3K9ac mitotic levels. HDAC2 inhibition, increased global H3K9ac in prophase, whereas HDAC3 or SIRT1 inhibition, increased H3K9ac levels in metaphase. Next, we performed ChIP-seq in mitotic cells following specific inhibition of each of these histone deacetylases. While we observed a high concordance between the genomic areas impacted by HDAC2 and HDAC3, we detected a small set of loci that were unique to each condition, with HDAC3-specific targets being enriched for genes involved in mitosis regulation. Examination of 4 different HDACs inhibitors in STC arrested mitotic Hela S3 cells. each experiment was done in duplicates and we also checked untreated mitotic cells and untreated unsynchronized cells