A Novel Testis-Enriched Gene Spata33 Is Expressed during Spermatogenesis

With an increasing incidence of male idiopathic infertility, identification of novel genes involved in spermatogenesis is an important aspect for the understanding of human testicular failure. In the present study, we have identified a novel gene Spata33, also called as 4732415M23Rik or C16orf55, which is conserved in mammalian species. Spata33 was predominantly expressed in the postpartum and adult mouse testes at mRNA and protein levels. Its expression was increased during the first wave of the spermatogenesis, indicating that Spata33 may be associated with the meiotic process. Further immunohistochemistry analysis revealed that Spata33 was mainly expressed in the spermatocytes, spermatogonia and round spermatids. Its expression was uniformly distributed in the nucleus and cytosol in these germ cells, which was further confirmed by Spata33-tagged with GFP staining in the GC-1 and TM4 cells. These results indicated that Spata33 was predominantly expressed in the mouse testis and associated with spermatogenesis. Identification and characterization of the novel testis-enriched gene Spata33 may provide a new route for understanding of spermatogenesis failure.