Detection of a transformation-related antigen in chemically induced sarcomas and other transformed cells of the mouse.

Abstract

Antisera prepared against BALB/c Meth A sarcoma in syngeneic or compatible F1 mice recognized a protein with an apparent MW of 53,000 in extracts of [35S]methionine-labeled transformed BALB/c cells. This component, designated p53, was not detected in normal adult mouse fibroblasts, lymphoid cells or hematopoietic cells or in mouse embryo cells or 3T3 [fibroblasts] cells. An extensive variety of antisera, including alloantisera and heterologous antisera directed against structural antigens of murine leukemia viruses, was tested for reactivity with p53. Other than Meth A antisera, only comparably prepared antisera against another BALB/c sarcoma, CMS4, had anti-p53 activity. All transformed mouse cells tested expressed p53. The tests included chemically induced sarcomas, leukemias, spontaneously transformed fibroblasts and cells transformed by SV40 and murine sarcoma virus. The presence of p53 in tumors of no known viral etiology indicated coding by resident cellular genes. This does not exclude endogenous viruses as the source of coding sequences or the possibility that transforming viruses code directly for p53.