A novel yeast histone deacetylase: partial characterization and development of an activity assay

We have characterized a histone deacetylase activity associated with yeast nuclei. An unusual feature of the deacetylase is that it is not inhibited by the short-chain fatty acids n-butyrate and propionate. These short-chain fatty acids are typically potent inhibitors of histone deacetylases in eukaryotic systems. The deacetylase(s) were detected by monitoring the levels of acetylation of yeast histones during incubation of isolated yeast nuclei. The activity was optimal at 37 degrees C and at 0.1 M NaCl. The enzyme did not require divalent cations and was inhibited by Zn2+ and Cu2+. A simple activity assay was developed using as substrate, [3H]acetate-labeled histone in chicken erythrocyte nuclei. This assay was used to demonstrate that the deacetylase(s) can be extracted from yeast nuclei with 0.5 M NaCl. A gel electrophoretic analysis of the deacetylated chicken histones verified that the solubilization of incorporated radiolabel was a result of histone deacetylation, not an artifact of histone degradation by yeast proteinases.