Rous sarcoma virus production from clones of nontransformed chick embryo fibroblasts

Abstract

When chick embryo cells are infected with high concentrations of Rous sarcoma virus (RSV) and cloned, most of the clones which produce RSV contain transformed cells. The remaining virus-producing clones, however, are normal in appearance. When cells from these nontransformed virus-producing clones are dispersed and recloned they give rise to clones, of which 90% are normal in appearance and produce no virus and 10% contain transformed cells and produce virus. It is suggested that nontransformed virus-producing clones arise from infected cells which grow into mixed clones. This occurs when virus is segregated to only one of the two daughter cells produced during the first divisions of a newly infected cell.