Structure and sequence of the cellular gene homologous to the RSV src gene and the mechanism for generating the transforming virus

Abstract

We determined the nucleotide sequences of all coding regions and a significant part of the flanking regions of the chicken c-src gene, which is a cellular homolog of the v-src gene of Rous sarcoma virus. The c-src gene consists of 12 exons; the boundaries of the exons were determined by assuming that the amino acid sequence of its product, pp60 c-src, is basically the same as that of pp60 v-src. The deduced amino acid sequence of pp60 c-src was very similar to that of pp60 c-src, but the last 19 carboxy-terminal amino acids of pp60 v-src were replaced by a new set of 12 amino acids of pp60 v-src. The sequence encoding the carboxy-terminal sequence of pp60 v-src was found 900 bp downstream from the termination codon of the c-src gene. We suggest that the c-src sequence was captured by a virus through recombination at both sides of the c-src gene, and that the recombinations occurred at the level of proviral DNA.