Identification of an atypical insect olfactory receptor subtype highly conserved within noctuids
Identification of an atypical insect olfactory receptor subtype highly conserved within noctuids
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DOI：
10.1111/j.1742-4658.2009.07351.x
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发表时间：
2009-11-01
期刊：
影响因子：
5.4
通讯作者：
Jacquin-Joly, Emmanuelle
中科院分区：
文献类型：
--
作者：
Brigaud, Isabelle;Montagne, Nicolas;Jacquin-Joly, Emmanuelle
嗅觉主要由嗅觉受体大家族介导。虽然所有昆虫嗅觉受体共享相同的结构与七个跨膜结构域，他们提出穷人的序列同源性内和物种之间。作为唯一的例外，果蝇OR 83 b及其直系同源物定义了一种在昆虫物种之间非常保守的受体亚型。在这篇文章中，我们报告了一个新的亚型的推定的嗅觉受体异常保守的昆虫，包括农作物害虫的分类组。通过同源性分子克隆，在不同属的6种昆虫触角中发现了与以前鉴定的烟芽夜蛾OR 18同源的序列，平均同源性为88%。在不同昆虫目的基因组中没有发现直系同源物，选择压力分析表明，昆虫OR 18处于纯化选择中。对棉夜蛾（Spodoptera littoralis）的嗅觉受体基因OR 18进行了详细的研究，结果表明：OR 18基因具有嗅觉受体编码基因的所有特征：其表达仅限于触角，在两性中均有表达，其发育表达模式与其他嗅觉基因相似;触角内的原位杂交实验表明，受体表达细胞与嗅觉结构密切相关，包括信息素敏感和非信息素敏感结构。两者合计，我们的数据表明，我们已经确定了一个新的原始亚型的嗅觉受体，是非常保守的martuids，并可能履行一个关键的功能，在男性和女性martuids化学感觉神经元。
Olfaction is primarily mediated by the large family of olfactory receptors. Although all insect olfactory receptors share the same structure with seven transmembrane domains, they present poor sequence homologies within and between species. As the only exception, Drosophila melanogaster OR83b and its orthologues define a receptor subtype singularly conserved between insect species. In this article, we report the identification of a new subtype of putative olfactory receptors exceptionally conserved within noctuids, a taxonomic group that includes crop pest insects. Through homology-based molecular cloning, homologues of the previously identified OR18 from Heliothis virescens were identified in the antennae of six noctuid species from various genera, presenting an average of 88% sequence identity. No orthologues were found in genomes available from diverse insect orders and selection pressure analysis revealed that the noctuid OR18s are under purifying selection. The OR18 gene was studied in details in the cotton leafworm, Spodoptera littoralis, where it presented all the characteristic features of an olfactory receptor encoding gene: its expression was restricted to the antennae, with expression in both sexes; its developmental expression pattern was reminiscent of that from other olfactory genes; and in situ hybridization experiments within the antennae revealed that the receptor-expressing cells were closely associated with the olfactory structures, including pheromone- and non-pheromone-sensitive structures. Taken together, our data suggest that we have identified a new original subtype of olfactory receptors that are extremely conserved within noctuids and that might fulfil a critical function in male and female noctuid chemosensory neurones.