Sequence organization of the human int-2 gene and its expression in teratocarcinoma cells

We report the genomic organization and DNA sequence of the human homologue of int-2, a proto-oncogene implicated in virally induced mammary tumours in the mouse, and expressed at specific sites and times during embryogenesis. Direct comparisons with the coding domains of mouse int-2 allowed us to delineate the intron-exon boundaries of the human gene. These boundaries were subsequently confirmed by ribonuclease protection analyses of the single 1.7 kilobase (kb) int-2 transcript detectable in the human teratocarcinoma cell line, Tera-2. The data suggest that human int-2 may also function in embryonic lineages but that its transcription may be less complex than in the mouse. The predicted human protein comprises 239 amino acids and is 89% homologous to its murine counterpart, except at the carboxy terminus. This divergence occurs distal to the region of int-2 that shows homology to other members of the FGF family of growth modulators and oncogenes.