FIG. 6.

Induction of p53 and apoptosis in p53^−/−, AY, and p53^S23A mouse thymocytes after IR. (A) Mouse thymocytes were recovered from AY-RAG2^−/− and p53^S23A-RAG2^−/− chimeric mice, stained for CD4 and CD8, and analyzed by flow cytometry. Cells residing in the lymphocyte gate were analyzed, and the percentages of total cells in a particular gate are indicated. (B) The percentage ratio of nonapoptotic CD4⁺ thymocytes in AY, p53^−/−, and p53^S23A thymocytes treated with 2.5, 5, 10, 15, and 20 Gy of IR to the nonapoptotic CD4⁺ thymocytes from untreated controls. Mean values from four independent experiments are presented with error bars. (C) p53 protein levels in AY and p53^S23A thymocytes at different times after IR treatment were determined by Western blot analysis. Time after treatment and genotypes are indicated at the top; p53 and actin are indicated on the right.