(A) Whole cell extracts infected with Ad-GFP (“GFP”) and Ad-antisense Hbo1 (“AS”) for 48 hr were analyzed by western blotting with antibodies to Hbo1, acetylated histone H4, and α-tubulin. (B) Whole cell extracts infected with Ad-Hbo1 (“WT”) and Ad-catalytically inactivated Hbo1 (“Mut”) for 48 hr were analyzed by western blotting with antibodies to Hbo1, acetylated histone H4, and α-tubulin. (C) Chromatin fractions of virus-infected MCF7 cells were separated on a protein gel, transferred to a membrane, were assayed for Histone H2B by immunoblotting to examine integrity of core histones.