YEAST FUNCTIONAL ASSAY OF THE P53 GENE STATUS IN HUMAN CELL-LINES MAINTAINED IN OUR LABORATORY

We used a yeast functional assay (functional analysis of separated all eles in yeast: FASAY) to determine the p53 gene status of human cell l ines maintained in our laboratory. This assay enables the researcher t o score wild-type p53 expression on the basis of the ability of expres sed p53 to transactivate the reporter gene HIS 3 via the p53-responsiv e GAL 1 promoter in Saccharomyces cerevisiae. The cell lines examined were ten hepatoma, two hepatoblastoma, three in vitro immortalized fib roblast, two osteosarcoma, a chondrosarcoma, an ovarian teratocarcinom a and a colon cancer cell line. Out of 20 cell lines, 11 cell lines ha d mutations in both alleles of the p53 gene, and another 8 cell lines had no mutation in the p53 gene. Thus, 55% of the cell lines examined had mutations in the p53, Interestingly, PA-1 cells had both the norma l and the mutant p53 alleles, showing that FASAY is a useful method fo r detecting the wild-type and mutated p53 genes simultaneously. As for the three liver cell lines harboring HBsAg, there was no relationship between their p53 gene status and the presence of HBsAg. Two cell lin es were normal for p53 status, while the other had a mutation of the p 53 gene.