Role of PML and c-Jun in UV-induced apoptosis. (A) Inhibition of c-Jun transcriptional function results in reduction of cell death upon UV radiation. Pml^+/+ and Pml^-/- MEFs were infected with pBabe (▦) or with a DN–c-Jun (▪). After 2 days of selection, cells were left untreated or UV-irradiated (60 J/m²). Cell death was measured by trypan blue uptake at 24 hours after the irradiation. Bars indicate fold induction of cell death over unirradiated controls. DN–c-Jun levels were measured in pBabe (B)- and DN–c-Jun (DN)–infected cells by using an anti–c-Jun antibody directed against the c-Jun C-terminus. Actin is shown as loading control. Data shown are representative of 3 independent experiments performed in duplicate. (B) c-Jun overexpression potentiates UV-triggered cell death. Pml^+/+ and Pml^-/- MEFs were infected with pBabe (▦) or c-Jun (▪) retroviruses and UV-treated as described earlier. Cell death was measured by trypan blue uptake at 24 hours after irradiation. Bars indicate fold induction of cell death over unirradiated controls. c-Jun levels were measured in pBabe (B)- and c-Jun (J)–infected cells by using an anti–c-Jun antibody directed against the c-Jun N-terminus. Actin is shown as control of loading. Data shown are representative of 3 independent experiments performed in duplicate. Error bars indicate standard deviation.