HDAC3 (UniProt/Swiss-Prot entry O15379) catalyses the deacetylation of lysine residues on the N-terminal part of the core histones (H2A, H2B, H3 and H4) and on some other non-histone substrates. Acetylation and deacetylation of these highly conserved lysine residues is important for the control of gene expression. When tethered to a promoter, HDAC3 represses transcription and therefore plays an important role in transcriptional regulation, cell cycle progression and developmental events. HDAC3 probably participates in the regulation of transcription through its binding to the YY1 transcription factor, increasing YY1 repression. HDAC3 also downregulates p53 and is considered a potential tumor suppressor gene.