中国明对虾caspase2基因克隆及其在抗白斑综合征病毒中的表达分析

采用RACE技术克隆获得中国明对虾caspase2基因cDNA序列全长,并对该序列进行分析。结果显示,中国明对虾caspase2基因全长为1517 bp,开放阅读框长924 bp,5'非编码区长78 bp,3'非编码区长515 bp,命名为FcCasp2。推测该基因编码307个氨基酸,预测分子量为34.21 ku,理论等电点为7.62。同源性和系统进化分析发现,FcCasp2基因与凡纳滨对虾caspase2和斑节对虾caspase的相似性分别为88%和80%,与其他节肢动物caspase家族基因聚为一类。荧光定量RT-PCR结果显示,FcCasp2基因在肝胰腺中的相对表达量最高,在肌肉中表达量最低。WSSV感染后该基因在中国明对虾肌肉、肝胰腺和鳃丝中的表达量有不同的时空表达趋势,表明FcCasp2基因可能参与中国明对虾生物胁迫的应答反应。

cDNA cloning of caspase2 gene in Fenneropenaeus chinensis and its expression analysis in WSSV infection

In this study, full-length cDNA sequence of caspase2 gene from Fenneropenaeus chinensis was first cloned using RACE method. The full-length cDNA sequence of caspase2 was 1517 bp, which contains a 78 bp 5'-UTR, 515 bp 3'-UTR and 924 bp open reading frame that encoded 307 amino acid residues, which had the isoelectric point(PI) of 7.62 and molecular mass of 34.21 ku. Homology analysis revealed that the amnio acid sequences of caspase2 highly identified with caspase family of other species, for example, it had 88% identity with caspase2 of Litopenaeus vannamei, and had 80% identity with caspase of Penaeus monodon. The phylogenetic analysis showed that Fenneropenaeus chinensis caspase2 was in the same class with other arthropods caspase. The expression levels of caspase2 gene in different tissues were analyzed by quantitative real-time PCR. The results showed that the highest level of caspase2 gene was in hepatopancreas. Real-time PCR analysis showed that the expression level of caspase2 was up-regulated distinctly in muscle, hepatopancreas and gill after stimulation with WSSV infection, and caspase2 showed different expression profiles. The results implied that caspase2 might play an important role in WSSV-challenge response of F. chinensis.