Mice were subjected or not to total body irradiation (IR) and after 2 h the indicated tissues were analyzed by a p53 immunofluorescence, b γ-H2AX immunofluorescence. Representative images from three (a) or two (b) independent experiments are shown. c, e Co-staining of p53 and γ-H2AX (c) or Ki67 (e) in the small intestine 2 h after irradiation. d, f Data from c and e, respectively, plotted as a function of cell position from the crypt base. Bold line shows running average; dots represent individual cells (n = 461 cells (d) and 615 cells (f)). g A diagram of crypt structure and summary of staining results in the small intestine. h TUNEL staining for indicted tissues in untreated mice or 5 h after ionizing radiation. Experiments were performed in duplicates.