Cooperation between gene encoding p53 tumour antigen and ras in cellular transformation.

The protein p53 is highly expressed in a large variety of transformed cell types originating from diverse species. These include cells transformed by Simian virus 40 (SV40), adenovirus and Abelson virus, as well as a variety of chemically transformed cells. Substantial amounts of p53 are also present in certain non-transformed cells, for example, some embryonic tissues. The protein may be localized in different cellular compartments in normal and transformed cells. The strong correlation between tumorigenicity and high levels of p53 suggests an important role of p53 in tumorigenesis. We report here experiments in which we have co-transfected the murine cellular gene encoding for p53 with a ras gene into primary rat embryo fibroblasts. Our results indicate that the p53-encoding gene can play a causal role in the conversion of normal fibroblasts into tumorigenic cells.