Cellular transformation and the 'morphologic phenotype' of transformed cells.

Expression of the product of the transforming gene (src) of RNA tumour viruses promotes growth and usually alters the adhesion, appearance and surface properties of cultured fibroblasts. The latter group of properties termed the 'morphologic phenotype' of transformed cells is largely due to diminished cell-to-substratum adhesion. The role of cyclic AMP, cell surface protein (CSP), and other factors in producing the 'morphologic phenotype' are discussed. The effects of src expression bear a striking resemblance to the action of peptide hormones such as insulin on appropriate target cells.     

The src gene product of transformed and morphologically reverted ASV-infected mammalian cells.

Morphological revertants of avian sarcoma virus transformed vole cells contain the sarcoma gene product (pp60src) in an enzymatically active form, suggesting that the presence of pp60src protein kinase activity is infussicient to induce morphological transformation. Structural analyses of pp60src from infected vole cell clones suggest that in one of the revertant clones on alteration in pp60src may be responsible for morphological reversion while in a second clone, reversion may result from an alteration in a cell gene product with which pp60src must interact. As these morphological revertant cells are tumorigenic, different cell components are required to interact with pp60src to facilitate the two events.