Purification and characterization of chicken erythrocyte histone deacetylase 1

Histone acetylation is involved in nuclear processes requiring chromatin remodeling. In chicken erythrocytes, DNA replication has ceased, and active reversible histone acetylation is restricted to transcriptionally active/competent chromatin domains. In this study, we set out to identify and purify the erythroid histone deacetylase responsible for catalyzing dynamic acetylation of transcriptionally active chromatin. Histone deacetylase purified from chicken erythrocytes had a molecular mass of 66 kDa. Complementary DNA encoding the chicken histone deacetylase was cloned from erythrocytes, and analysis of the derived amino acid sequence showed the chicken histone deacetylase to be the chicken homologue of mammalian HDAC1. Purified chicken erythrocyte HDAC1 deacetylated the four core histones, with a preference for H3. We present evidence that chicken HDAC1 is a metalloenzyme, the activity of which is lost when incubated with zinc chelators. In Western blot analysis with anti-HDAC1 antibodies, we found that most erythrocyte HDAC1 is associated with the low-salt insoluble chromatin fraction and, to a lesser extent, with 150 mM NaCl-soluble oligo- and polynucleosomes. The distribution of HDAC1 in erythrocyte chromatin parallels that of dynamically acetylated class 1 histones. Further, we show that HDAC1 is associated with the erythroid nuclear matrix and that the enzyme is bound to nuclear DNA in situ. We propose that in addition to catalyzing dynamic acetylation of transcribed chromatin, the enzyme has a role in the organization of nuclear DNA.