Transforming genes of avian (v-fps) and mammalian (v-fes) retroviruses correspond to a common cellular locus.

The Gardner (GA) and Snyder-Theilen (ST) isolates of feline sarcoma virus (FeSV) represent genetic recombinants between feline leukemia virus (FeLV) and transformation-specific sequences (v-fes gene) of cat cellular origin. A related transforming gene (v-fps), common to the Fujinami, PRC II, and UR 1 strains of avian sarcoma virus has also been described. Translational products of each of these recombinant virus isolates are expressed in the form of polyproteins exhibiting protein kinase activities with specificity for tyrosine residues. In the present study, v-fes and v-fps homologous sequences of GA-FeSV, ST-FeSV, and Fujinami sarcoma virus (FSV) are defined and these independently derived transforming genes are shown to correspond to a common cellular genetic locus which has remained highly conserved throughout vertebrate evolution.