半滑舌鳎Vasa基因cDNA克隆及其在繁殖周期的表达

摘要

The Vasa gene encodes a protein of DEAD-box family that is essential for PGCs proliferation. In this study,we characterized the cDNA of Vasa and researched its expression in the reproductive cycle of Cynoglossus semilaevis through RACE and RT-PCR technology, aiming to clarify its function in gametogenesis of fishes. The length ef Vasa gene is 2 602 bp and this gene encodes a protein of 722 amino acids. The dudced amino acid sequence contains 8 conserved motifs of DEAD-box family protein, 5 RGG repeats and 10 RG repeats in N-terminal region. Comparisons of the deduced amino acid sequence with those of other vertebrates and invertebrates revealed the highest homology (91% ) with Thunnus orientalis. Vasa was strongly expressed in gonad and little expressed in heart. In the reproductive cycle, the transcript level of Vasa gene in the primary yolk stage and tertiary yolk stage is higher than peri-nucleolus stage and atretic follicles in ovary. The transcript level of spermatogenesis stage is obviously higher than that of spermatocyte stage and spermiation stage. These results suggest that Vasa gene may play an important role in spermatogenesis and oogenesis during reproductive cycle.%通过简并引物和RACE技术分离得到了半滑舌鳎Vasa基因的cDNA序列,其全长为2 602 bp,编码包含722个氨基酸残基的蛋白质.半滑舌鳎Vasa在N末端含有5个RGG重复和10个RG重复,具备DEAD-box家族特有的8个保守基序,与东方蓝旗鲔的同源性最高(91％).利用RT-PCR技术研究了csVasa在性成熟半滑舌鳎中的表达模式.组织分布研究发现,Vasa在半滑舌鳎的卵巢和精巢中表达丰富,心脏中有微量表达；繁殖周期中,卵巢中Vasa的表达量在初级卵黄期和囊泡期要明显高于核周期和退化吸收期；精巢中,Vasa在精子细胞增殖期的表达量要显著高于精子成熟期和精母细胞增殖期.结果表明,Vasa可能在半滑舌鳎的配子发生中起重要作用.