Fig. 5.

Histograms of repair time. The cell count vs. the repair time is plotted for a population of 2,000 cells with and without p53 regulation (red and black lines, respectively) at the IR dose of 4 Gy (A), 5 Gy (B), or 6 Gy (C). The blue line denotes the threshold time for cell fate decision. With p53 regulation, the repair process depends on the levels of p53 and DNA damage, i.e., p53 promotes the repair of minor damage but suppresses the repair of severe damage. A threshold of 175 DSBs is set to distinguish between low and high damage levels.