摘要： 为阐明松墨天牛肌肉收缩机理和相关基因表达模式,用构建cDNA文库方法,从松墨天牛cDNA中克隆到松墨天牛肌球蛋白轻链2基因,命名为 MaMLC-2 (GenBank:KM371003)。该基因cDNA为882 bp,其中开放阅读框(ORF)为618 bp,编码205个氨基酸,推测的蛋白等电点为4.66,分子量为22.26 kDa。MaMLC-2的氨基酸序列与赤拟谷盗同源性最高,为96%,与东方蝼蛄等8种昆虫同源性为85% ~88%。松墨天牛与赤拟谷盗处在系统发育树的同一分支上。MaMLC-2属于亲水性氨基酸,存在2个EF-hand结构域,长度均为29个氨基酸,其中第1个EF-hand结构域含有 Ca²⁺结合位点。SWISS-MODEL预测结果显示,MaMLC-2有2个螺旋-环-螺旋结构。用 RT-qPCR 分析了 MaMLC-2 基因的相对表达量,结果显示:蛹和幼虫的表达量高于成虫;成虫中足表达量最高,腹部表达量最低,各部位均有表达,且有显著差异(P<0.05)。

关键词: 松墨天牛, 肌球蛋白轻链2, 基因表达模式, RT-qPCR

Abstract: In order to elucidate the muscle contraction mechanism and related gene expression pattern of Monochamus alternatus,the myosin light chain 2 gene from Monochamus alternatus,called MaMLC-2 (GenBank:KM371003) was cloned by using cDNA library construction.The cloned cDNA of MaMLC-2 was 882 bp in length,which contains a 618 bp open reading frame (ORF) encoding 205 amino acids with a calculated molecular mass of 22.26 kDa and an isoelectric point of 4.66.MaMLC-2 showed the highest homology with Tribolium castaneum (96%),and has amino acid sequence homology with the myosin light chain 2 from 8 species of insects such as Gryllotalpa orientalis (85% -88%). M.alternatus and T.castaneum on the same branch in the phylogenetic tree based on insect myosin light chain 2 amino acids.MaMLC-2 was hydrophilic,which contains 2 EF-hand functional domains,and both of the domains are comprised of 29 amino acids.The first EF-hand functional domain can bind Ca²⁺.There was a Ca²⁺ binding site in the first EF-hand domain.SWISS-MODEL prediction results showed that MaMLC-2 has 2 helix-loop-helix structures.The relative expression levels of MaMLC-2 detected by RT-qPCR indicated that the expression levels of MaMLC-2 in pupae and larvae were higher than that in adults,and the expression level in head of adults was the highest,nevertheless,the expression level in abdomen of adults was the lowest.The MaMLC-2 were prominently and differently expressed in all of the adult parts(P<0.05).

Key words: Monochamus alternatus, Myosin light chain 2, Gene expression pattern, RT-qPCR

中图分类号: 

• Q966