Radioresistance and increased proliferation of <i>Rnf8^−/−</i> cells in the absence of p53.

<p>(A) Freshly isolated thymocytes from <i>Rnf8^−/−p53^−/−</i> mice and control littermates were irradiated with 2 Gy and cell death was determined 12 hours later. Data are presented as the means SD of at least 5 independent experiments. * represents significant difference (P<0.05; student t-test) compared to <i>WT</i> and <i>Rnf8^−/−</i> controls. No difference was observed between <i>p53^−/−</i> and <i>Rnf8^−/−p53^−/−</i> thymoctes. (B) Freshly isolated splenocytes were irradiated (2 Gy) and cell death was determined 24 hours later. Data are presented as the means SD of at least 5 independent experiments. * represents statistical significance (P<0.05; student t-test) compared to <i>WT</i> and <i>Rnf8^−/−</i> controls. No significant difference was observed between <i>p53^−/−</i> and <i>Rnf8^−/−p53^−/−</i> splenocytes. (C) Cumulative growth curve of <i>Rnf8^−/−p53^−/−</i> MEFs. Passage 2 <i>Rnf8^−/−p53^−/−</i> MEFs and controls were plated in 60 mm plates at a density of 3×10⁵ cells/plate. Cells were replated at the same density every 3 days and cumulative cell growth was calculated. Data are presented as the log10 of means ± SD of at least 5 independent experiments.