SPECIFIC REPERTOIRE OF OLFACTORY RECEPTOR GENES IN THE MALE GERM-CELLS OF SEVERAL MAMMALIAN-SPECIES

Olfactory receptors constitute the largest family among G protein-coup led receptors, with up to 1000 members expected. We have previously sh own that genes belonging to this family were expressed in the male ger m line from both dog and human. We have subsequently demonstrated the presence of one of the corresponding olfactory receptor proteins durin g dog spermatogenesis and in mature sperm cells. In this study, we inv estigated whether the unexpected pattern of expression of olfactory re ceptors in the male germ line was conserved in other mammalian species . Using reverse transcription-PCR with primers specific for the olfact ory receptor gene family, about 20 olfactory receptor cDNA fragments w ere cloned from the testis of each mammalian species tested. As a whol e, they displayed no sequence specificity compared to other olfactory receptors, but highly homologous, possibly orthologous, genes were amp lified from different species. Finally, their pattern of expression, a s determined by RNase protection assay, revealed that many but not all of these receptors were expressed predominantly in testis. The male g erm line from each mammalian species tested is thus characterized by a specific repertoire of olfactory receptors, which display a pattern o f expression suggestive of their potential implication in the control of sperm maturation, migration, Or fertilization. (C) 1997 Academic Pr ess.