Role of p53 gene in genetic instability induced by ionizing radiation

Abstract To know the role of p53 gene for delayed somatic mutation, we analysed T-cell receptor (TCR) mutation in X-irradiated mice. Wild-type p53 (+/+) and heterozygous p53 (+/−) mice were given a whole-body acute exposure of 3 Gy X-ray at 8 weeks of age. TCR assays were done at various time intervals between 9 days and 40 weeks after exposure. In p53 (+/−) mice, TCR mutation frequency (TCR-MF) increased again 36 weeks after irradiation. However, in p53 (+/+) mice, TCR-MF did not increase again. These findings show that the loss of p53 function becomes relevant to the acquisition delayed mutations.