p53 deficiency rescues the senescence of <i>Rnf8^−/−</i> MEFs.

<p>(A) Western blot analysis of <i>Rnf8^−/−p53^−/−</i> and control MEFs for p21 and p19^ARF under untreated conditions and following 8 Gy ionizing radiation. β-actin is used as a loading control. * indicates a non specific band. (B) Western blot analysis of phosphorylated Ser-p53 and total p53 in untreated or γ-irradiated <i>Rnf8^−/−p53^−/−</i> and control MEFs. β-actin was used as a loading control. * indicates a non specific band. (C) Senescence-associated β-galactosidase staining of <i>Rnf8^−/−</i> MEFs and controls. MEFs were fixed and stained with X-gal solutions. The cells were then visualized using a brightfield microscope. These images are representative of three different experiments. (D) Quantification of the percentages of β-galactosidase-positive cells for 3 different experiments. * indicates P<0.05. Bar: 500 µm.