Depsipeptide induction of histone H3 acetylation in CLL cells. Histone H3 acetylation increases in the majority of CLL cells following treatment with depsipeptide. CLL cells were incubated in media or depsipeptide (0.038 and 0.38 μM) for 4 hours. Acetylation of H3 was analyzed at 4 hours by immunofluorescence detection with Cy3-conjugated antiacetylated H3 and appropriate negative control antibodies. Magnification is × 100 in all panels.