Binding between wild-type p53 and hsp72 accumulated after UV and gamma-ray irradiation.

We have investigated the increased levels of p53 and hsp72 after UV or gamma-ray irradiation and the association of these using two human glioblastoma cell lines. Human glioblastoma cell line A-172 exhibited no mutations in the p53 gene, whereas cell line T98G had a mutation in exon 7 of the p53 gene. In A-172, the level of wild-type p53 was increased by UV or gamma-ray irradiation. Although the level of mutant p53 in T98G was very high before irradiation, it was unchanged by UV or gamma-ray irradiation. Furthermore, in the A-172 cell line after UV or gamma-ray irradiation, wild-type p53 was co-immunoprecipitated with anti-hsp72/73 antibody, and accumulated hsp72 was also co-immunoprecipitated with anti-p53 antibody. These findings indicate that wild-type p53 accumulated by UV or gamma-ray irradiation is associated with hsp72 induced by these treatments.