REDUCED UV-INDUCED MUTATIONS IN HUMAN OSTEOSARCOMA CELLS STABLY EXPRESSING TRANSFECTED WILD-TYPE P53 CDNA

We constructed the plasmid which can express human wild-type p53 cDNA and introduced it into the human osteosarcoma cell line SAOS-2 that la cks the chromosomal p53 gene. A cell clone stably expressing p53 prote in was isolated and UV sensitivity and UV-induced mutation frequencies of the clone were examined. The UV sensitivity of the clone was sligh tly higher and UV-induced hprt mutation frequencies of the clone were markedly lower than those of parental SAOS-2 cells. The capability to repair UV-induced DNA damage assessed by the amount of unscheduled DNA synthesis or DNA single strand breaks as well as cell cycle progressi on after UV irradiation were not different between the clone and SAOS- 2 cells. These results indicate that wild-type p53 protein would be in volved in the human DNA damage-processing pathway other than the genom e-overall excision repair. (C) 1998 Elsevier Science Ireland Ltd.