THE STATE OF IMMORTALIZED, TRANSFORMING AND SUPPRESSOR GENES IN RAT-CELLS, TRANSFECTED BY POLYOMAVIRUS LARGE-T AND HPV18 E6+E7 GENES

Several novel cell clones (A1-A6) derived from the rat embryo fibrobla sts immortalized by the polyoma virus T-antigen (LT) gene and transfor med by HPV18 E6 and E7 genes were explored. Using E6 or E7 peptide ant isera we detected E6 and E7 proteins with approximate molecular masses of 16 kDa and 20 kDa, respectively. Monoclonal antibody to p53 PAb421 but not PAb240 precipitated different but appreciable amounts of p53 protein in all cell clones, indicating that wild-type p53 is expressed in these cells. So expression of HPV18 E6 protein in cells does not a lways lead to a complete reduction in p53 levels. The quantity of p53 protein in cell clones did not correlate with the level of polyoma vir us large T-antigen expression. Variations in levels of p53 protein in clones did not influence on such cell biological properties as anchora ge-independence and tumorigenicity for nude mice which were similar in all cell clones.