Component of the RPD3C(L) histone deacetylase complex (HDAC). Responsible for the deacetylation of 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. ASH1 is necessary to repress HO in daughter cells to block mating-type switching through its binding to HO promoter 5'-YTGAT-3' sites. Also involved in pseudohyphal growth. Component of the RPD3C(L) complex composed of at least ASH1, CTI6, DEP1, PHO23, RPD3, RXT2, RXT3, SAP30, SDS3, SIN3, UME1 and UME6. Preferentially accumulates in daughter cell nuclei at the end of anaphase. The ASH1 mRNA is transported to the daughter cell before cytokinesis where translation produces the protein to block mating-type switching. The ASH1 mRNA 3'-UTR and the mRNA localization machinery that are essential to restrict accumulation to the bud. Present with 1800 molecules/cell in log phase SD medium.