文蛤SRBI基因克隆及其在不同壳色群体中的差异表达

CLONING AND EXPRESSION ANALYSIS OF SRBI GENE IN DIFFERENT SHELL-COLOR STRAINS OF MERETRIX MERETRIX

  • 摘要: 为了研究SRBI基因的结构、功能以及在贝类壳色形成中的作用, 利用SMART RACE技术克隆得到文蛤(Meretrix meretrix) SRBI (Mm-SRBI)基因的全长序列, 并对其内含子特征及不同组织、不同壳色群体外套膜中的表达差异进行了分析。结果表明: Mm-SRBI基因cDNA全长1676 bp, 开放阅读框1515 bp, 编码504个氨基酸, 结构域预测发现有一个CD36结构域; 氨基酸序列比对发现, 与华贵栉孔扇贝的同源性最高(55%), 与其他物种的相似性在34%—40%, 表明该基因变异较大; 在Mm-SRBI基因中扩增出12个内含子, 均存在于开放阅读框中, 且都遵循GT-AG原则; 荧光定量PCR (qRT-PCR)结果表明, Mm-SRBI在闭壳肌、外套膜、斧足、鳃、内脏团和水管6个组织均有表达, 其中在外套膜中表达量显著高于其他组织(P<0.01), 这可能与外套膜中类胡萝卜素含量较高有关; 不同壳色群体外套膜中基因表达分析表明,Mm-SRBI在黑斑和红壳文蛤中的表达量显著高于白壳文蛤(P<0.05)。实验结果为文蛤壳色形成研究奠定了基础。

     

    Abstract: To explore the molecular structure and biological function of SRBI in the process of carotenoids accumulation in Meretrix meretrix, we cloned cDNA of Mm-SRBI by SMART RACE technique and conducted the bioinformatics, expression analysis and intron amplification. The full length cDNA of Mm-SRBI is 1723 bp that contains a complete 1515 bp ORF encoding 504 amino acids with one functional domain of Mm-SRBI protein (CD36). Mm-SRBI is highly homologous with Mimachlamys nobilis and shares 55% similarity in amino acid sequence. It shares 34%—40% similarity with vertebrates. We also amplified 12 introns of Mm-SRBI, which followed the principle of GT-AG. Mm-SRBI gene expressed in all six tested tissues with the highest level in mantle (P<0.01), suggesting thatMm-SRBI gene maybe relate to high carotenoid in mantle. Moreover, the expression of Mm-SRBI gene in red shell strain was significantly higher than that of white shell strain (P<0.05). In conclusion, this study provides helpful foundation to explore the shell colors on this species.

     

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