Targeting P300/CBP reveals discrete regulation of transcription and chromatin accessibility by histone acetylation [Hi-C]

ABSTRACT: To test the long-standing paradigm directly linking histone acetylation with chromatin decompaction and transcriptional output, we used integrated epigenomic and transcriptomic analyses following acute inhibition of major cellular lysine acetyltransferases P300 and CBP. We discovered that P300/CBP inhibition dynamically perturbs acetylation kinetics and dramatically suppresses core-transcriptional networks in the absence of changes to chromatin accessibility. CRISPR/Cas9 screening identified NCOR1 and HDAC3 transcriptional co-repressors as the principle antagonists of P300/CBP by counteracting acetylation turnover kinetics. Finally, deacetylation of H3K27 provides nucleation sites for reciprocal methylation switching, a feature that can be exploited therapeutically by concomitant KDM6A and P300 inhibition. Overall, this study indicates that the steady-state histone acetylation-methylation equilibrium functions as a molecular rheostat governing cellular transcription that is amenable to therapeutic exploitation as an anti-cancer regimen.

ORGANISM(S): Homo sapiens

PROVIDER: GSE173781 | GEO | 2021/05/11

REPOSITORIES: GEO