HD1

Histone deacetylase 1 (HDAC1) is a class I histone deacetylase that regulates chromatin structure and gene expression through removal of acetyl groups from histone and non-histone proteins^[1][2]. HDAC1 functions as a catalytic component of transcriptional corepressor complexes, including Sin3A, NuRD, and CoREST complexes, which regulate transcriptional repression and cellular differentiation programs^[2][3]. Mechanistically, HDAC1 controls epigenetic regulation by modulating histone acetylation states, including regulation of histone H3 acetylation marks associated with transcriptional activity^[2]. In experimental models, HDAC1 contributes to regulation of embryonic stem cell differentiation, erythroid differentiation, cell proliferation, and cancer-associated transcriptional programs^[3][4]. HDAC1-containing complexes regulate cancer cell responses by controlling transcriptional networks involved in proliferation, survival, and cellular stress adaptation^[4]. Compared with the closely related isoform HDAC2, HDAC1 has distinct biological functions, as genetic deletion of HDAC1 but not HDAC2 affects specific differentiation processes and reduces the activity of HDAC1/2-containing corepressor complexes^[3]. HDAC1 also differs from other HDAC family members through its preferential association with Sin3A, NuRD, and CoREST transcriptional regulatory complexes^[2][3]. For experimental applications, HDAC1 function is investigated using genetic depletion, catalytic activity assays, chromatin analysis, and pharmacological inhibition approaches^[1][4]. HDAC inhibitors are widely used to study HDAC1-dependent transcriptional regulation and cellular phenotypes, although many inhibitors target multiple HDAC family members rather than HDAC1 selectively^[5].