HDAC1 (histone deacetylase 1) is a 65 kD member of the Class I histone deacetylase family, similar to the yeast RPD3 protein. This nuclear protein operates in concert with histone acetyltransferases to control core histone acetylation in highly conserved lysine residues. HDAC activity has been associated with transcriptional repression and nucleosomal condensation. HDAC1 can be modified by phosphorylation and sumoylation. HDAC1 has been shown to interact with protein phosphatase 1, Rb, MyoD (muscle cells), and the mSin3a co-repressor complex. The Poly6074 antibody has been shown to be useful for Western blotting of human and mouse HDAC1.