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.