棉铃虫嗅觉受体基因的克隆及组织特异性表达

昆虫嗅觉受体是一个高度变异的蛋白家族，但是其中一类嗅觉受体很特殊，它们在不同昆虫体内高度保守。该文作者从棉铃虫Helicoverpa armigera体内克隆得到了这类受体基因，命名为ORHarm。ORHarm编码473个氨基酸残基，序列中有7个跨膜区，是典型的G蛋白偶联的受体。ORHarm与已经报道的昆虫同类嗅觉受体的同源性在60％以上，与近缘种烟芽夜蛾Heliothis virescens嗅觉受体的同源性高达99.4％。半定量RT-PCR研究表明，ORHarm主要在棉铃虫成虫触角中表达，在喙中也有表达，但表达量较低，在成虫其他的部位不表达；在棉铃虫发育的各个时期，如卵、幼虫、蛹和成虫体内，也都有表达。ORHarm不仅在感受挥发性气味物质的过程中起着重要的作用，而且也参与液态化学刺激的识别过程。

Gene cloning and tissue-specific expression of an olfactory receptor in Helicoverpa armigera

Olfactory receptors in insects were found to be extremely diverse, but there is one exception. There is a kind of olfactory receptor, which shares a rather high identity among different insects. The gene encoding the similar olfactory receptor from Helicoverpa armigera was cloned and named as ORHarm. The ORHarm encoded 473 amino acid residues, including seven putative transmembrane domains, which is the typical characteristic of G protein-coupled receptors. ORHarm shares very obvious homology (>60%) with similar olfactory receptors reported from other insects and the homology with the close sibling species Heliothis virescens reaches 99.4%. Semi-quantitative RT-PCR analysis showed that ORHarm was highly expressed in antenna of H. armigera moth, low expressed in proboscis and not expressed in other tissues of the moth. ORHarm was also expressed in different developmental stages of egg, larva, pupa and imago. ORHarm may play important roles in sensing volatile odors as well as sensing liquid chemical stimulates.