Depsipeptide induction of lysine-specific changes in histone acetylation. The amount of global and lysine-specific acetylated H3 and H4 in CLL cells increases in a dose-dependent manner following a 4-hour incubation with depsipeptide. Patients' mononuclear cells were isolated and cultured in media or depsipeptide (0.04 and 0.4 μM) for 4 hours. Histone extractions were performed at 4 hours and analyzed by SDS-PAGE/immunoblotting with antihuman antibodies for acetylated H3 and H4 and specific lysine residues on these histones. Equivalent loading was verified by staining with Coomassie blue.