Figure 6.

H3K56 deacetylation and acetylation is not regulated by ATR checkpoint kinase. (A) Seckel cells are proficient in the deacetylation and restoration of H3K56 acetylation in response to UV irradiation. Seckel cells were exposed to 10 J m⁻² UV radiation and were harvested at the indicated times. Whole cell lysates prepared from the cells were resolved on SDS–PAGE and H3K56 acetylation levels determined by western blotting. (B) ATR deficiency does not affect either the deacetylation or restoration of H3K56 acetylation in response to UV irradiation. HeLa cells were transfected with 100 nM ATR siRNA using Lipofectamine tansfection reagent. At 48 h after transfection, cells were irradiated with 10 J m⁻² UV and harvested at the indicated times. Whole-cell lysates were prepared, resolved on SDS–PAGE and H3K56Ac levels determined by western blotting with anti-H3K56Ac antibodies.