Original Article Gamma-Radiation-Induced Phosphorylation of p53 on Serine

Abstract. Molecular indicators of the absorbed dose of ionizing radiation are powerful tools in biodosi-metry. The studies reported here were undertaken with the motivation to find such a marker among the mo l-ecules involved in ataxia-telangiectasia mutated ki-nase-dependent signalling induced by ionizing radia-tion (ATM-kinase, checkpoint kinase-2, protein p53, and oncoprotein Mdm2). In our previous work on T-lymphocyte leukaemia MOLT-4 cells we described the mentioned molecules of ATM-dependent path-way and none of them showed a pronounced dose-dependent response. Here we employed Western blotting and ELISA assay to investigate the response of post-translationally modified p53 (particularly phosphorylated on serine 15) after gamma-irradia-tion. We have found the amount of phosphorylated p53 to be homogenously increased after irradiation by the doses of 0.5 to 7.5 Gy. The dose-dependent re-sponse was pronounced especially after the doses up to 3.0 Gy. The presented data indicate that p53 phos-phorylated on serine 15 might be used as a potential biodosimetric marker