东亚飞蝗储存蛋白基因LmiHex-2的克隆与表达分析

Cloning and Expression Analysis of a Hexamerin Gene Lmi Hex-2 from Locusta migratoria manilensis( Acridoidea: Oedipodidae)

昆虫储存蛋白是在昆虫体内普遍存在的一种特异性淋巴蛋白,在昆虫的生长发育过程中发挥着重要作用。为分析东亚飞蝗Locusta migratoria manilensis储存蛋白基因Lmi Hex-2的结构和时空表达特性,通过RACE技术获得了Lmi Hex-2基因2 171 bp全长c DNA序列,其中开放阅读框2 022 bp,编码673个氨基酸,预测分子量78.79 k Da。序列比对结果显示Lmi Hex-2基因c DNA序列与直翅目蝗总科储存蛋白基因c DNA序列的相似性达到82%~89%。RT-PCR结果显示Lmi Hex-2基因在东亚飞蝗卵和若虫阶段均有表达,5龄6 d时表达量最大;成虫中脂肪体表达量最高。通过贝叶斯法构建的系统发育树显示直翅目储存蛋白为单系群,昆虫血蓝蛋白与昆虫储存蛋白聚为姐妹群,二者均由甲壳纲血蓝蛋白进化而来。

Hexamerins are large hemolymph-proteins that accumulate in insects during the late larval stages and play important roles in insect development and growth. To investigate the structure and expression profiles of Locusta migratoria manilensis hexamerin（ Lmi Hex-2）,the complete c DNA（ 2 171 bp） of Lmi Hex-2 was obtained by RACE method. The Lmi Hex-2 contained an open reading frame of 2 022 bp,which encoded 673 amino acids with a predicted molecular mass of 78.79 k Da. Sequence alignment revealed that the Lmi Hex-2 shared an identity of 82% ~ 89% with hexamerins from other Acridoidea species. RT-PCR results showed that Lmi Hex-2 gene was expressed both in nymphs and adults. After 6 d 5th instar nymphs,the relative expression quantity of Lmi Hex-2 reached a maximum. In adult males and females,the fat body exhibited the highest level of Lmi Hex-2 transcripts. The phylogenetic tree showed that Orthoptera hexamerins was a monophyletic group,the Insecta hexamerins and the Insecta hemocyanins,which evolved from Crustacea hemocyanins and form a sister group.