The present invention features, inter alia, purified antibodies that selectively bind an isolated or recombinant histone deacetylase polypeptide comprising the amino acid sequence as set forth in SEQ ID NO: 2, which comprises a histone deacetylase catalytic domain at amino acids 635 to 953 of SEQ ID NO: 2, purified antibodies that selectively bind a biologically active fragment of the polypeptide of SEQ ID NO: 2, which fragment exhibits histone deacetylase activity, transcription repression activity, and the ability to deacetylate cellular substrates, purified antibodies that selectively bind an isolated or recombinant histone deacetylase polypeptide encoded by a nucleotide sequence as set forth in SEQ ID NO: 1, purified antibodies that selectively bind an isolated or recombinant histone deacetylase polypeptide comprising the amino acid sequence as set forth in SEQ ID NO: 2 lacking a nuclear localization signal, and purified antibodies that selectively bind an isolated or recombinant histone deacetylase polypeptide having at least 95% amino acid sequence identity to SEQ ID NO: 2 and which exhibits histone deacetylase activity, transcription repression activity, and the ability to deacetylate cellular substrates.