拟穴青蟹vasa基因cDNA的特征分析与性腺特异表达

vasa蛋白属于DEAD家族蛋白,是一种RNA解旋酶,在生殖细胞的分化中具有重要作用。本研究从拟穴青蟹卵巢中克隆得到vasa基因cDNA全长(将其命名为Sp-vasa),Sp-vasa序列长度为2 944 bp,其中开放阅读框(ORF)长度为1 899 bp,编码632个氨基酸,具有DEAD-box家族蛋白的7个高度保守的结构域。半定量RT-PCR结果显示,Sp-vasa只在卵巢和精巢中特异表达,在其它组织则未检测到表达。由此可见,vasa属于拟穴青蟹性腺特异表达基因。因此,Sp-vasa基因可有望作为有效的分子指标研究拟穴青蟹原始生殖细胞的起源、迁移以及生殖腺的发生。

cDNA cloning and characteristic of vasa gene in the gonad of mud crab, Scylla paramamosain

The vasa gene encodes DEAD box family protein of ATP-dependent RNA helicase,which plays a crucial role in primordial germ cell proliferation.The full length of vasa cDNA(Sp-vasa) from the ovary of Scylla paramamosain was cloned by Rapid Amplification of cDNA End(RACE) methods.The Sp-vasa cDNA comprised of 2 944 bp,containing 182 bp in the 5′-untranslated region,1 899 bp in the open reading frame(ORF) and 863 bp in the 3′-untranslated region.Analysis of the deduced protein sequence of Sp-vasa showed that it encoded 632 amino acids which shared the seven conserved motifs of the DEAD box family: AQTGSGKT(Motif I),PTRELA(motif Ia),DEAD(motif II),SAT(motif III),LVFVE(motif IV),RGLD(motif V),HRIGRTGR(motif VI) and GG repeats.Furthermore,semi-quantitative RT-PCR analysis revealed that Sp-vasa mRNA was detectable only in the ovary and testis of S.paramamosain.Therefore,it was deduced primarily that Sp-vasa could be a useful maker for investigating the origin,migration and differentiation of germline of S.paramamosain.