A Sequence Homologous to Rous Sarcoma Virus v-src is on Human Chromosome 20

Cellular sequences (c-src) homologous to the v-src gene of Rous sarcoma virus (RSV) are present in the genomic DNAs of all vertebrates examined and have been evolutionarily conserved. The v-src gene is responsible for the malignant transformation of cells and is expressed as a 60,000-dalton phosphoprotein, designated as pp6Ov-src, with protein kinase activity. Using Southern hybridization techniques and man-mouse somatic cell hybrids, a human c-src gene is assigned to chromosome 20 in the chapter. Cellular DNAs were cut with EcoRI and probed with a 3.1-kb EcoRI DNA fragment containing v-src derived from pSRA-2, a recombinant plasmid containing the genome of the Schmidt–Ruppin A strain of RSV. The v-src gene hybridizes principally to a large EcoRI fragment of human DNA and to two EcoRI fragments of mouse DNA. The presence of additional minor bands that hybridize to v-src suggests that other src-related genes might be present in human and mouse genomes. Human cells contain two related but distinct forms of pp60c-src; however, it is not known whether the two forms are the products of separate c-src genes.