FIG. 5.

Expression of 53BP2 sensitizes cells to UV irradiation-induced apoptosis. (A) Percentage of 293/53BP2 and 293/LZ cells with apoptotic nuclear morphology 48 h after UV irradiation (shaded bars) or no UV irradiation (open bars). Cells induced to express 53BP2 or β-galactosidase (+) were treated with 2.5 μM ponasterone A for 24 h prior to UV irradiation. Mock-induced cells (−) were treated with an equivalent volume of control carrier (ethanol). Shown are the means and standard deviations from triplicate plates. (B) Western blot using anti-53BP2 monoclonal antibody DX547 of equivalent amounts of lysates prepared from 293/53BP2 cells induced for 24 h with 2.5 μM ponasterone A (+) or ethanol (−).