Sequences coding for part of oncogene-induced transin are highly conserved in a related rat gene

The transin gene is induced by oncogenes and epidermal growth factor (EGF). We report here the isolation of a related gene (transin-2 gene). The structures of these genes are very similar. Indeed, a stretch of 428 nucleotides of the transin gene containing both exon and intron sequences is 98% conserved in the transin-2 gene. However, the putative promoter regions of the genes show little sequence homology, apart from a short element related to a sequence involved in control of transcription by cyclic AMP or a tumour promoter. Expression of the transin-2 gene, unlike that of the transin gene, is not induced by EGF, dibutyryl cyclic AMP or cytochalasin D. Nevertheless, transin-2 RNA is expressed in several transformed rat embryo fibroblast cell lines, and can be induced by a tumour promoter. The proteins transin and transin-2 are approximately 71% homologous in sequence. Both proteins show significant sequence homology with two connective tissue degrading metalloproteases. These homologies raise the possibility that expression of transin and transin-2 in transformed cells might play a role in tumour invasion.