Expression of a testis-specific member of the olfactory receptor gene family in human primordial germ cells

Olfactory receptors are G protein-coupled transmembrane receptors, Genes en coding olfactory receptors constitute a large gene family of similar to 100 0 total member genes. In mammals, a subset of member genes is specifically expressed in the testis (and not in the olfactory mucosa) and olfactory rec eptor proteins have been identified in elongated spermatids and mature sper matozoa of dogs. It is postulated that olfactory receptors may recognize si gnal molecules present in the female genital tract and play a role in chemo taxis of spermatozoa towards the oocyte, In a previous study, we identified 10 cDNA sequences, corresponding to genes specifically expressed in human primordial germ cells (PGC), by differential display, Sequence analysis rev ealed that one of these sequences appeared to be a member of the olfactory receptor gene family. To investigate this further, we have used degenerate oligonucleotide primers corresponding to conserved amino acid sequences of olfactory receptor proteins to amplify all the olfactory receptor genes exp ressed in the PGC, Sequence analysis of a total of 30 cloned sequences disc losed that one member gene, which was previously isolated from a human test is cDNA library by others, was also preferentially expressed in our PGC, Ou r results suggest that specific members of the olfactory receptor gene fami ly may have a function in germ cells in the migratory phase of their life c ycle.