Granzyme N (GZMN)

Granzyme N, a Novel Granzyme, Is Expressed in Spermatocytes and Spermatids of the Mouse Testis1. The Gzmn mRNA was specifically expressed in the testes of adult mice. The Gzmn expression was found to initiate in the testes at 3 wk of age and to become more prominent as the animal reached sexual maturity. In situ hybridization analysis revealed that both spermatocytes and spermatids of the adult mouse testes express Gzmn mRNA. Consistent with these findings, the protein was immunohistochemically detected in the spermatocytes and spermatids, although some of the germ cells showed no positive staining. Gzmn was demonstrated to be a secretory and N-glycosylated protein that exists in two protein forms in the testes extract. Gzmn is not involved in the process of germ cell apoptosis induced by heat shock, but that it may be involved in spermatogenesis in the mouse testes.