凡纳滨对虾肌钙蛋白Ⅰ型基因4种不同剪切体的序列分析

采用RT-PCR技术克隆了凡纳滨对虾肌钙蛋白Ⅰ基因全长编码序列，对其核苷酸序列和编码的氨基酸序列进行了生物信息学分析，并在对虾肌钙蛋白Ⅰ基因的编码区查找了单核苷酸多态性位点。结果显示：本研究克隆获得了凡纳滨对虾肌钙蛋白Ⅰ基因的4个可变剪切体，其编码的蛋白质均具有Troponin超家族结构域特征，同源性比对发现该蛋白的氨基酸序列在节肢动物中高度保守。系统进化分析发现凡纳滨对虾Tn-Ⅰ3和Tn-Ⅰ4与中国对虾和小龙虾的Tn-Ⅰ遗传距离较近，而Tn-Ⅰ1和Tn-Ⅰ2单独聚为一支，且与其他物种Tn-Ⅰ遗传距离较远；通过测序比较不同个体凡纳滨对虾Tn-Ⅰ基因序列发现在Tn-Ⅰ的4种不同剪切体编码区共同序列区第302位和472位碱基分别存在2个（A/G） SNP位点，其中位于第302位碱基的（A/G）错义突变使编码氨基酸由甘氨酸变为了谷氨酸（G/E）。凡纳滨对虾Tn-Ⅰ基因不同剪切体及编码区错义突变的发现为进一步探讨其基因功能奠定了基础。

Sequence analysis of troponin I genes four different spliced variant in Litopenaeus vannamei

Troponin I gene of Litopenaeus vannamei was clone by RT-PCR technology. The nucleotide and deduced amino acid sequence of troponin I were analyzed. The SNP of troponin I gene was searched by sequencing in different individuals. The results showed four splice variants of troponin Ⅰ were isolated from Litopenaeus vannamei tissues, and the deduced amino acid sequences encoded by different variants of troponin Ⅰ have same troponin super family domain, and these sequences highly conserve among arthropod animals. The phylogenetic analysis based on amino acid sequence shows that there is higher similarity in Tn-Ⅰ3 and Tn-Ⅰ4 of Litopenaeus vannamei, Fenneropenaeus chinensis and Crayfish, but Tn-Ⅰ1 ofLitopenaeus vannamei was together with Tn Ⅰ2 of Litopenaeus vannamei individually. Two （A/G） SNPs at nucleotide 302 and 472 in the same coding sequences of four splice variants of Litopenaeus vannamei Tn Ⅰ were found by sequencing, and a transition A G at nucleotide 302 caused a Glycine glutamate missense mutation. For the first time four splice variants of troponin Ⅰ in Litopenaeus vannamei were cloned and a missense mutation was founded,these provide a good foundation for further research on its function.