Probably mediates the deacetylation of lysine residues lysine residues on the N-terminal part of the core histones (H2A, H2B, H3 and H4). Histone deacetylation gives a tag for epigenetic repression and plays an important role in transcriptional regulation, cell cycle progression and developmental events. A number of isoforms are produced. According to EST sequences. Confined to stems and flowers with young siliques. HDT4 is not required for the cellular patterning in the root epidermis. Belongs to the histone deacetylase HD2 family.