The nucleotide sequence of the human int-1 mammary oncogene; evolutionary conservation of coding and non-coding sequences.

The mouse mammary tumor virus can induce mammary tumors in mice by proviral activation of an evolutionarily conserved cellular oncogene called int-1. Here we present the nucleotide sequence of the human homologue of int-1, and compare it with the mouse gene. Like the mouse gene, the human homologue contains a reading frame of 370 amino acids, with only four substitutions. The amino acid changes are all in the hydrophobic leader domain of the int-1 encoded protein, and do not significantly alter its hydropathic index. The conservation between the mouse and the human int-1 genes is not restricted to exons; extensive parts of the introns are also homologous. Thus, int-1 ranks among the most conserved genes known, a property shared with other oncogenes.