Expression and Distributing of vasa Gene During Gametogenesis of Goldfish (Carassius auratus)

Using in situ hybridization with DIG antisense RNA probe, we detected the expression and distributing of goldfish (Carassius auratus) DEAD-box family gene vasa during oogenesis and spermatogenesis. The results showed that during oogenesis, the positive signals of vasa RNA were detected in the cytoplasm of oocytes at all stages. In stage Ⅰand Ⅱ oocytes, strong hybridization signals of vasa RNA were dispersed uniformly throughout the cytoplasm. With the development of oocytes and accumulation of yolk, the signals of vasa RNA significantly decreased in most of the regions while remained strong at cortical region in stage Ⅲ, Ⅳ oocytes. During spermatogenesis, the positive signals of vasa RNA could only be detected in spermatogenia and primary spermatocytes while the signals in the former were much stronger than in the latter. However, no signals could be detected in spermatids. Our results suggested that gene vasa may play an important role in the early stage of goldfish spermatogenesis; vasa RNA is deposited in oocytes and subsequently regulate the germ cells specification and differentiation during the early embryogenesis.