FIGURE 3.

Degradation of Bora is required for G₂/M checkpoint activation. U2OS cells were infected with lentiviruses encoding Bora shRNA. 48 h later, cells were transfected with shRNA-resistant WT or T501A Bora. Cells were left untreated or UV-irradiated (20 J/m²) or IR (10 gray). A, cells were lysed 1 h post-radiation and blotted with the indicated antibodies. B, cells were fixed at 1 h, and the mitotic index was determined by phospho-H3 staining. C, cells were UV-irradiated (20 J/m²) and fixed at the indicated time, and the mitotic index was determined by phospho-H3 staining. D, cells were UV-irradiated (20 J/m²).1 h later, cells were incubated in medium containing nocodazole and stained with phospho-H3 antibody at the indicated time to determine the mitotic index. 1000 cells were counted. The results represent the mean values from three independent experiments. Error bars represent S.E. #, p > 0.05; *, p < 0.05; **, p < 0.01.