表現序列標幟(EST)功能註解分析的新流程

表現序列標幟(expressed sequence tag, EST)是cDNA序列片段，直接研究EST可獲取基因表現訊息。針對EST功能的註解、分類及表現量統計分析，本研究建立了一套完整且快速的新流程：將EST資料經CAP3軟體聚集和接合後所獲得的較高品質和去除多餘性的單一序列(unique sequences)，去比對TIGR(The Institute for Gene Research)之TC(tentative consensus sequence)資料庫以進行功能註解，再藉由TC搜尋結果連結到GO(Gene Ontology)與MIPS(Munich Information Center for Protein Sequences)之功能分類系統進行功能分類，最後進行基因功能表現量之統計。褐飛蝨[Nilaparvata lugens (Stal.)]是亞洲地區重要的水稻(Oryza sativa L.)蟲害，為利於瞭解水稻對褐飛蝨的基因防禦機制，本研究以取自NCBI之dbEST資料庫中受褐飛蝨誘導的EST 序列資料作為應用材料，利用所建立的功能註解分析流程，進行不同水稻抗、感性品種間基因功能表現的差異性比較。分析結果顯示，受褐飛蝨誘導之水稻抗、感品種在GO功能分類上，皆以生物程序的功能表現為主；而在更細分的MIPS功能分類上，抗性品種在生物程序中的代謝相關基因的表現量較感性品種為高，同時抗性品種啟動了感性品種所沒有的細胞逆境防禦反應（援救、防禦和毒性）、轉錄、及細胞生長和形態發生的基因功能表現。

關鍵字

表現序列標幟；聚集及接合；功能註解；分類目錄；基因表現量統計；水稻；褐飛蝨

並列摘要

Expressed sequence tag (EST) is the fragment of cDNA sequence. Direct study of EST is therefore helpful to obtain the gene expression information. A complete and rapid procedure including EST functional annotation, classification and representation statistics was established as the followings. The first step was to use unique sequences of high quality from removing redundancy after clustering and assembling by CAP3 software to homology search TC (tentative consensus sequence) database of TIGR (The Institute of Genomic Research). The second step was to link the functional catalogs of GO (Gene Ontology) and MIPS (Munich Information Center for Protein Sequences) from tentative annotation of the selected TC sequences. Finally the statistics of gene functional representation was calculated. Brown planthopper [Nilaparvata lugens (Stal.)] is the major pest of rice (Oryza sativa L.) in Asia. In order to know the mechanisms of rice genes resistant to brown planthopper, we used rice EST sequences induced by brown planthopper from NCBI-dbEST database as materials to compare the gene expression differences between the resistant and sensitive varieties. Using our procedure of EST functional annotation and analysis, the results showed that the dominant gene function of rice ESTs induced by brown planthopper was biological process based on GO functional category. According to minute classification of MIPS functional category system, the genes of resistant rice variety expressed richer metabolism function than that of sensitive rice variety. The resistant rice variety switched on the gene functions related to cell rescue/defense and virulence, transcription, and cell growth/morphogenesis, but sensitive variety did not.

並列關鍵字

Expressed sequence tag ； Clustering and assembly ； Functional annotation ； Classification catalogue ； Statistics of gene representation ； Rice ； Brown planthopper

國際替代計量

表現序列標幟(EST)功能註解分析的新流程

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