DIFFERENT REGULATION OF P53 STABILITY IN UV-IRRADIATED NORMAL AND DNA-REPAIR DEFICIENT HUMAN-CELLS

The stabilization of p53 protein was studied after UV exposure of norm al human skin fibroblasts and cells derived from patients suffering fr om xeroderma pigmentosum (XP) and trichothiodystrophy (TTD). The data show that p53 is transiently stabilized both in UV-irradiated normal a nd repair deficient cells. However, particularly at later times after UV irradiation, stabilization of p53 persists much longer in repair de ficient XP and TTD cells than in normal cells. The stabilization of p5 3 was found to be dose-dependent in normal and XP cells. These results indicate that unremoved DNA damage could possibly be responsible for the induction of transient stabilization of p53.