Figure 6

Tip60-knockdown also repressed both HR activity and acetylation of histone H2A. (A) Tip60-knockdown reduced acetylation of histone H2A. MRC5SV cells were transfected by Tip60 siRNA. After 2 days, these cells were irradiated by 5 Gy of γ-ray and were harvested at indicated times after IR and analyzed by Western blot using indicated antibodies. (B) HR activity in Tip60-knockdowned cells. M5D cells were transfected by Tip60 siRNA. After 2 days, I-SceI expression plasmids were introduced by electroporation. After 3 days, GFP-positive cells were analyzed by flowcytometer. (C) The effect of pentamidine on HAT activity of Tip60. Whole cell extract was prepared from irradiated or un-irradiated HeLa cells. And then, Tip60-dependent HAT activity was measured with or without pentamidine (5 μM) as described in Material and Methods. (D) Pentamidine repressed Tip60-dependent acetylation of p53. MRC5SV cells were added by 0.5 mM adriamycin with or without pre-treatment of pentamidine (0.5 mM, 30 minutes). These cells were harvested after 4 hours and analyzed by Western blot using anti-acetylated p53 antibody.