生物谷綜合：近日，中國科學院動物研究所研究員康樂領導的研究組,，在昆蟲特有蛋白的鑒定中取得突破性進展。他們通過分析完全變態(tài)與不完全變態(tài)昆蟲的基因組信息,，并與其他真核生物的基因組信息進行比較,，鑒定出51種昆蟲特有蛋白，包括與環(huán)境脅迫和感受刺激相關的蛋白,、表皮蛋白和氣味結合蛋白等,，揭示了昆蟲在環(huán)境適應與信息交流方面的獨特特征。相關論文發(fā)表在國際著名基因組學雜志《英國醫(yī)學委員會·基因組學》（BMC Genomics）上,。
康樂告訴《科學時報》記者,，昆蟲是世界上種類最多的高等生物類群，據(jù)估計世界上昆蟲種類大約有100多萬種,。研究昆蟲的基因組和蛋白質組學對生物多樣性,、農業(yè)和人類健康等具有重要意義。昆蟲種類的多樣性,、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,，昆蟲多樣性的分化是對環(huán)境的適應和億萬年長期進化的結果。導致昆蟲高度多樣性的原因和內在的遺傳機制并不完全清楚。昆蟲特有蛋白是昆蟲物種分化,、行為習性和形態(tài)上區(qū)別于其他生物種類的重要特征,，但到底哪些蛋白屬于昆蟲特有蛋白并不清楚。
這項研究的對象包括不完全變態(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、小鼠和人類的基因組進行了細致的比較,。“我們成功鑒定了51種昆蟲特有蛋白,，其中許多是昆蟲的表皮蛋白和氣味結合蛋白。表皮蛋白與昆蟲的蛻皮,、變態(tài)等重要生理過程密切相關,，而氣味結合蛋白在昆蟲尋找食物與配偶的過程中發(fā)揮重要作用，說明在昆蟲的進化與分化過程中,，對環(huán)境的適應與交流對于塑造昆蟲的形態(tài)與生理特征起到了關鍵的作用,。”康樂說，這項研究向世人揭示,，昆蟲盡管有著豐富多彩的外形和迥異的習性,，但是造成這種多樣性的原因，并不像人們原來認識的那樣,，即以為原因是昆蟲擁有多樣化的蛋白,。
對這些蛋白的基因進行KaKs分析發(fā)現(xiàn)，大多數(shù)昆蟲特有蛋白有很低的KaKs值,，說明這些蛋白在進化過程中突變率低,，能夠為昆蟲提供穩(wěn)定的蛋白質組成。研究中通過比對發(fā)現(xiàn),，昆蟲特有蛋白的基因序列具有較少的冗余,，可能也為昆蟲提供了優(yōu)于其他真核生物的環(huán)境適應優(yōu)勢。“既比較穩(wěn)定,，也比較善于適應環(huán)境,，昆蟲的特有蛋白確實很有趣,。對其功能的進一步驗證,，有助于科學家推測昆蟲億萬年來在基因組與蛋白質組方面的進化過程。我們的研究證明,，昆蟲生命形式的多樣性并不是通過增加大量不同的基因實現(xiàn)的,。”康樂告訴記者。
國際同行對文章給出了高度評價,，他們認為：“作者進行了一項十分值得贊揚的工作,，成功鑒定出的昆蟲特有蛋白,，對研究昆蟲進化具有重大的創(chuàng)新意義。”“這篇文章十分有趣地研究了昆蟲的核心蛋白,，而這些蛋白在哺乳動物,、線蟲和真菌中從未被發(fā)現(xiàn)過。”“作者推測了昆蟲的基因組和蛋白質組是如何進化的,，所有的分析十分細致,，文章中的大量數(shù)據(jù)非常有意義，這是一個非常有趣的論題,。”“昆蟲與人類的生活息息相關,，每年昆蟲的危害都給農作物生產和人類健康造成很大損失，通過基因組學與蛋白質組學信息分析尋找昆蟲特有蛋白,，是發(fā)現(xiàn)昆蟲防治新途徑的重要手段,，該項研究具有重要的理論價值與實際意義。”
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.
