The Characteristics of vasa Gene from Japanese Sea Bass(Lateolabrax japonicas) and Its Response to the External Hormones The Characteristics of vasa Gene from Japanese Sea Bass(Lateolabrax japonicas) and Its Response to the External Hormones

The RNA helicase Vasa is an important regulator of primordial germ cell development. Its function in mature fish, especially the hormone-related differences in maturing male fish has seldom been documented. In this study, a full length c DNA sequence of the vasa gene was cloned from Japanese sea bass, Lateolabrax japonicas, and it was named jsb-vasa. Homology analysis showed that jsb-vasa was closely related to its teleost homologs. The spatial distribution of jsb-vasa indicated that it was only highly expressed in testis, showing its germ cell-specific expression pattern. During the testicular development cycle, jsb-vasa was highly expressed during early period of spermatogenesis, and reduced when spermatogenesis advanced. In addition, the jsb-vasa gene expression was significantly inhibited at 6 h, 12 h and 24 h after injecting h CG(human chorionic gonadotropin) and Gn RHa(Gonadotropin-releasing hormone analogue), indicating that jsb-vasa gene may play an important role in spermatogenesis of Japanese sea bass, and be under the regulation of external sex hormones