Rat C-Type Virus induced in Rat Sarcoma Cells by 5-Bromodeoxyuridine

HALOGENATED derivatives of uridine are highly effective inducers of latent C-type RNA viruses1,2 and have been successfully used to induce viruses identical to, or similar to, the C-type RNA tumour viruses in mouse, rat, and human cells3-6. In previous experiments we used 5-bromodeoxyuridine (BrUdR) for induction of focus-forming virus in non-productive rat cells that have been transformed by mouse sarcoma virus2. We describe here the induction of a C-type RNA virus in the cells of the rat tumour cell line XC, which contains the Rous sarcoma virus genome7. The induced virus possesses the group specific (gs) antigens of rat C-type viruses but not those of chicken C-type viruses.