Contact relationships between chick embryo cells growing in monolayer culture after infection with Rous sarcoma virus

Abstract

An electron microscopic examination was made of cell contacts and associated microfilament arrays in subconfluent cultures of chick embryo fibroblasts (CEF) and chick embryo retinal pigmented epithelium cells (RPE) transformed by strains of Rous sarcoma virus (RSV) imparting a rounded (Morph r) or fusiform (Morph f) transformed morphology. A few cell substrate contact specializations were found in Morph r-transformed CEF and RPE cells. These resembled cell/substrate plaques of uninfected fibroblasts, but lacked associated microfilament tracts. In contrast Morph f-transformed CEF and RPE resembled untransformed fibroblasts having well developed cell/substrate and cell/cell contact specializations with extensive associated microfilament arrays. Morph r- and Morph f-transformed RPE cells had lost the junctional complex typical of untransformed RPE cultures and additionally no melanosomes were found. SEM and TEM demonstrated differences in adhesive properties of CEF and RPE cell surfaces, few virions adhering to the free cell surface of RPE cells but being found in clumps and singly on CEF cells.