Growth-related alterations induced in chick embryo fibroblasts by src-gene deletion mutants of the Schmidt-Ruppin strain of Rous sarcoma virus.

Certain tdSRD viruses induce multilayered cell foci, agar colony formation, and increased density of cellular populations in line-15 chick embryo fibroblasts. These alterations in cellular growth properties are distinct from oncogenic transformation. Available evidence favors the idea that transformation-defective focus formation is caused by one or more of the replicative viral genes, but which of the three-gag, pol, or env-is involved, remains to be determined.