生物谷綜合：近日,，中國(guó)科學(xué)院動(dòng)物研究所研究員康樂(lè)領(lǐng)導(dǎo)的研究組,，在昆蟲(chóng)特有蛋白的鑒定中取得突破性進(jìn)展,。他們通過(guò)分析完全變態(tài)與不完全變態(tài)昆蟲(chóng)的基因組信息,，并與其他真核生物的基因組信息進(jìn)行比較，鑒定出51種昆蟲(chóng)特有蛋白,，包括與環(huán)境脅迫和感受刺激相關(guān)的蛋白,、表皮蛋白和氣味結(jié)合蛋白等，揭示了昆蟲(chóng)在環(huán)境適應(yīng)與信息交流方面的獨(dú)特特征,。相關(guān)論文發(fā)表在國(guó)際著名基因組學(xué)雜志《英國(guó)醫(yī)學(xué)委員會(huì)·基因組學(xué)》（BMC Genomics）上,。
康樂(lè)告訴《科學(xué)時(shí)報(bào)》記者，昆蟲(chóng)是世界上種類(lèi)最多的高等生物類(lèi)群,，據(jù)估計(jì)世界上昆蟲(chóng)種類(lèi)大約有100多萬(wàn)種,。研究昆蟲(chóng)的基因組和蛋白質(zhì)組學(xué)對(duì)生物多樣性、農(nóng)業(yè)和人類(lèi)健康等具有重要意義,。昆蟲(chóng)種類(lèi)的多樣性,、行為和生理的多樣性以及遺傳的多樣性在生物界中都是最高的，昆蟲(chóng)多樣性的分化是對(duì)環(huán)境的適應(yīng)和億萬(wàn)年長(zhǎng)期進(jìn)化的結(jié)果,。導(dǎo)致昆蟲(chóng)高度多樣性的原因和內(nèi)在的遺傳機(jī)制并不完全清楚,。昆蟲(chóng)特有蛋白是昆蟲(chóng)物種分化、行為習(xí)性和形態(tài)上區(qū)別于其他生物種類(lèi)的重要特征,，但到底哪些蛋白屬于昆蟲(chóng)特有蛋白并不清楚,。
這項(xiàng)研究的對(duì)象包括不完全變態(tài)的飛蝗，完全變態(tài)的果蠅,、蜜蜂,、埃及伊蚊和家蠶的基因組信息，并與主要的真核生物真菌,、線蟲(chóng),、小鼠和人類(lèi)的基因組進(jìn)行了細(xì)致的比較。“我們成功鑒定了51種昆蟲(chóng)特有蛋白,，其中許多是昆蟲(chóng)的表皮蛋白和氣味結(jié)合蛋白,。表皮蛋白與昆蟲(chóng)的蛻皮、變態(tài)等重要生理過(guò)程密切相關(guān),，而氣味結(jié)合蛋白在昆蟲(chóng)尋找食物與配偶的過(guò)程中發(fā)揮重要作用,，說(shuō)明在昆蟲(chóng)的進(jìn)化與分化過(guò)程中,，對(duì)環(huán)境的適應(yīng)與交流對(duì)于塑造昆蟲(chóng)的形態(tài)與生理特征起到了關(guān)鍵的作用。”康樂(lè)說(shuō),，這項(xiàng)研究向世人揭示,，昆蟲(chóng)盡管有著豐富多彩的外形和迥異的習(xí)性，但是造成這種多樣性的原因,，并不像人們?cè)瓉?lái)認(rèn)識(shí)的那樣,，即以為原因是昆蟲(chóng)擁有多樣化的蛋白。
對(duì)這些蛋白的基因進(jìn)行KaKs分析發(fā)現(xiàn),，大多數(shù)昆蟲(chóng)特有蛋白有很低的KaKs值,，說(shuō)明這些蛋白在進(jìn)化過(guò)程中突變率低，能夠?yàn)槔ハx(chóng)提供穩(wěn)定的蛋白質(zhì)組成,。研究中通過(guò)比對(duì)發(fā)現(xiàn),，昆蟲(chóng)特有蛋白的基因序列具有較少的冗余，可能也為昆蟲(chóng)提供了優(yōu)于其他真核生物的環(huán)境適應(yīng)優(yōu)勢(shì),。“既比較穩(wěn)定,，也比較善于適應(yīng)環(huán)境，昆蟲(chóng)的特有蛋白確實(shí)很有趣,。對(duì)其功能的進(jìn)一步驗(yàn)證,，有助于科學(xué)家推測(cè)昆蟲(chóng)億萬(wàn)年來(lái)在基因組與蛋白質(zhì)組方面的進(jìn)化過(guò)程。我們的研究證明,，昆蟲(chóng)生命形式的多樣性并不是通過(guò)增加大量不同的基因?qū)崿F(xiàn)的,。”康樂(lè)告訴記者。
國(guó)際同行對(duì)文章給出了高度評(píng)價(jià),，他們認(rèn)為：“作者進(jìn)行了一項(xiàng)十分值得贊揚(yáng)的工作,，成功鑒定出的昆蟲(chóng)特有蛋白，對(duì)研究昆蟲(chóng)進(jìn)化具有重大的創(chuàng)新意義,。”“這篇文章十分有趣地研究了昆蟲(chóng)的核心蛋白,，而這些蛋白在哺乳動(dòng)物、線蟲(chóng)和真菌中從未被發(fā)現(xiàn)過(guò),。”“作者推測(cè)了昆蟲(chóng)的基因組和蛋白質(zhì)組是如何進(jìn)化的,，所有的分析十分細(xì)致，文章中的大量數(shù)據(jù)非常有意義,，這是一個(gè)非常有趣的論題,。”“昆蟲(chóng)與人類(lèi)的生活息息相關(guān)，每年昆蟲(chóng)的危害都給農(nóng)作物生產(chǎn)和人類(lèi)健康造成很大損失,，通過(guò)基因組學(xué)與蛋白質(zhì)組學(xué)信息分析尋找昆蟲(chóng)特有蛋白,，是發(fā)現(xiàn)昆蟲(chóng)防治新途徑的重要手段，該項(xiàng)研究具有重要的理論價(jià)值與實(shí)際意義,。”
原始出處：
BMC Genomics 2007, 8:93 doi:10.1186/1471-2164-8-93
published 4 April 2007
Identification and characterization of insect-specific proteins by genome data analysis
Guojie Zhang* 1 ,2 ,3 , Hongsheng Wang* 1 , Junjie Shi* 2 , Xiaoling Wang2 , Hongkun Zheng2 , Gane Ka-Shu Wong2 , Terry Clark4 , Wen Wang3 , Jun Wang2 ,5 and Le Kang1
1State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology Chinese Academy of Sciences, Haidian Beijing 100080, China
2Beijing Institute of Genomics of Chinese Academy of Sciences, Beijing Genomics Institute, Beijing 101300, China
3CAS-Max Plank Junior Research Group, Key Laboratory of Cellular and Molecular Evolution, Kunming Institute of Zoology, Chinese Academy of Science (CAS), Kunming, Yunnan 650223, China
4Department of Electrical Engineering and Computer Science, The University of Kansas, 2001 Eaton Hall, Lawrence, KS 66044, USA
5Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230, Odense M, Denmark
Abstract
Background
Insects constitute the vast majority of known species with their importance including biodiversity, agricultural, and human health concerns. It is likely that the successful adaptation of the Insecta clade depends on specific components in its proteome that give rise to specialized features. However, proteome determination is an intensive undertaking. Here we present results from a computational method that uses genome analysis to characterize insect and eukaryote proteomes as an approximation complementary to experimental approaches.
Results
Homologs in common to Drosophila melanogaster, Anopheles gambiae, Bombyx mori, Tribolium castaneum, and Apis mellifera were compared to the complete genomes of three non-insect eukaryotes (opisthokonts) Homo sapiens, Caenorhabditis elegans and Saccharomyces cerevisiae. This operation yielded 154 groups of orthologous proteins in Drosophila to be insect-specific homologs; 466 groups were determined to be common to eukaryotes (represented by three opisthokonts). ESTs from the hemimetabolous insect Locust migratoria were also considered in order to approximate their corresponding genes in the insect-specific homologs. Stress and stimulus response proteins were found to constitute a higher fraction in the insect-specific homologs than in the homologs common to eukaryotes.
Conclusion
The significant representation of stress response and stimulus response proteins in proteins determined to be insect-specific, along with specific cuticle and pheromone/odorant binding proteins, suggest that communication and adaptation to environments may distinguish insect evolution relative to other eukaryotes. The tendency for low Ka/Ks ratios in the insect-specific protein set suggests purifying selection pressure. The generally larger number of paralogs in the insect-specific proteins may indicate adaptation to environment changes. Instances in our insect-specific protein set have been arrived at through experiments reported in the literature, supporting the accuracy of our approach.
