Molecular cloning and expression of rat contraception associated protein 1 (CAP1), a protein putatively involved in fertilization.

Epididymal fluid from rats rendered infertile by oral administration of ornidazole contains a protein CAP1 (contraception-associated protein 1) that is absent from epididymal fluid, but present on epididymal sperm, from fertile vehicle-treated rats. The gene for CAP1 has been isolated from a rat testis cDNA library and its expression investigated in different tissues. The deduced protein sequence of CAP1 contains 189 amino-acid residues and database searches revealed a high degree of homology (83-95%) with human and mouse DJ-1 at the nucleotide and amino acid levels. Northern blot hybridisation from different rat tissues indicated that CAP1 is encoded by a 1.6-kilobase RNA transcript and seems to be ubiquitiously expressed in the rat with a high level of expression in the testis. Copyright 1998 Academic Press.