Morphological revertants of an avian sarcoma virus-transformed mammalian cell line exhibit tumorigenicity and contain pp60src.

The biological and biochemical properties of Rous sarcoma virus-transformed and revertant field vole cells were investigated. Revertant vole cells appear morphologically similar to normal, uninfected cells, yet, like transformed vole cells, they are fully capable of growing in agar suspension and producing tumors in athymic nude mice. These highly tumorigenic, yet morphologically normal appearing, vole cells express viral-specific antigens such as the gag gene product (Pr76) but lack the env gene protein (gp85). Moreover, they contain the src gene protein, pp60src. These results support the concept of the pleiotropic nature of the src gene product and in addition suggest that pp60src may have multiply mechanisms of action. With this revertant cell system it may be feasible to distinguish between those biochemical functions of the src gene product that are important for tumorigenicity in vivo and those that are related to in vitro morphological transformation.