Vasa and dazl genes have been reported to play pivotal roles in germ cell development and differentiation both in vertebrates and invertebrates; however, little is known about their functions in germ cell differentiation during gametogenesis and sex reversal in hermaphroditic fish. In the present study, vasa (Ecvasa) and dazl (Ecdazl) cDNA were cloned from orange-spotted grouper (Epinephelus coioides). The full-length cDNA sequences of Ecvasa and Ecdazl were 2162 and 2101 bp, and encoded 646 and 214 amino acid residues, respectively. Reversal transcription PCR showed that Ecvasa and Ecdazl mRNA were highly expressed in the gonads. Further, in situ hybridization revealed that Ecvasa and Ecdazl RNA were dynamically expressed in germ cells at different stages during oogenesis, sex reversal, and spermatogenesis in orange-spotted grouper. Intriguingly, the signals for Ecvasa and Ecdazl mRNA became weaker in oocytes of ovo-testes gonads, indicating that the expression of germ cell genes could be suppressed in oocytes during sex reversal in the orange-spotted grouper. Our study is the first time to describe the expression profiles of vasa and dazl mRNA in germ cells during gametogenesis and sex reversal in the orange-spotted grouper. These findings will provide new insights into understanding the mechanisms through which vasa and dazl regulate germ cell differentiation in hermaphrodite fish species.

据报道，Vasa和dazl基因在脊椎动物和无脊椎动物的生殖细胞发育和分化中起关键作用。然而，关于雌雄同体鱼类在配子发生和性逆转期间它们在生殖细胞分化中的功能了解甚少。在本研究中，从橙斑石斑鱼（Epinephelus coioides）中克隆了vasa（Ecvasa）和dazl（Ecdazl）cDNA 。Ecvasa和Ecdazl的全长cDNA序列为2162和2101 bp，分别编码646和214个氨基酸残基。逆转录PCR显示Ecvasa和Ecdazl mRNA在性腺中高表达。此外，原位杂交显示Ecvasa和Ecdazl RNA在橙色斑点石斑鱼的卵子发生，性逆转和精子发生过程中的不同阶段在生殖细胞中动态表达。有趣的是，卵睾丸性腺的卵母细胞中Ecvasa和Ecdazl mRNA的信号变弱，表明在橙色斑点石斑鱼的性逆转期间，卵母细胞中生殖细胞基因的表达可能受到抑制。我们的研究是第一次描述vasa和dazl的表达谱桔斑石斑鱼配子发生和性逆转期间生殖细胞中的mRNA。这些发现将为了解瓦萨和达兹尔调节雌雄同体鱼类中生殖细胞分化的机制提供新的见解。