凡纳滨对虾3个sHSP成员的序列与表达特征分析

Sequence and Expression Analysis of Three sHSP from Litopenaeus vannmei

通过搜索凡纳滨对虾EST数据库,获得3个包含完整开放阅读框的sHSP cDNA序列。对3个sHSP cDNA和相应蛋白序列进行多序列比对发现,3个sHSP的cDNA序列同源性非常高,均达到95%以上,但在开放阅读框第376 bp之后,3个基因间有多个插入和缺失突变,使编码的蛋白序列在C端有较大差异,sHSP-1与sHSP-2、sHSP-3蛋白的同源性只有86.5%和78.7%。不同物种多个sHSP蛋白序列构建的系统进化树显示,3个sHSP与其他物种的HSP20.6、HSP21.4和HSP Beta亲缘关系都很近,推测不同物种sHSP起源相似,且同一物种的不同sHSP通过基因复制产生。运用荧光定量PCR分析了sHSP-1和sHSP-2基因在凡纳滨对虾不同组织及低温胁迫处理下的表达,结果显示,sHSP-1和sHSP-2均在肌肉组织中优势表达,并在低温诱导对虾肌肉组织中呈上调表达,暗示sHSP基因可能在对虾应对低温时发挥功能。

Three sHSP cDNAs with whole ORF （open reading frame） were got from the EST library of Litopenaeus vannmeiby data mining.Multi-alignment of the 3 sHSP cDNAs and corresponding proteins revealed that the sHSP cDNAs have high identity with each other,while the proteins have much more diversity in its C-terlminal,owing to the insert and default mutations in ORFs after 376bp.Phylogenetic tree constructed by sHSP proteins from different species revealed that the 3 sHSP from Litopenaeus vannmei were similar to HSP20.6,HSP21.4 and HSP Beta from other species.Real-time PCR showed that sHSP-1 and sHSP-2 were mainly expressed in muscle and their expression were up regulated in muscle of low temperature treated shrimp,which indicate the sHSPs may function in cold tolerance of shrimp.