轉位子Ds1顯子化提供玉米基因轉錄及蛋白衍生體之新功能訊息

轉位子插入基因隱子中，可造成該基因轉錄時選擇轉位子所提供之剪接位點(splice site)稱選擇性剪接(alternative splicing)，若因此轉位子之遺傳序列併入轉錄體(即mRNA)則稱顯子化(exonization)。針對單一插入事件，玉米轉位子Ds可提供4組剪接供位(splice donor)，至多產生4種異構物；而Ds1轉位子可提供3組剪接供位以及2組剪接受位(splice acceptor)，至多產生11種異構物。先前模擬Ds及Ds1插入植物基因隱子之研究顯示，顯子化事件利用Ds/Ds1提供之剪接位點，將插入位點上下游隱子序列導入轉錄產物中，可提供基因新轉錄體及轉譯後之蛋白衍生體，因而提高轉錄體豐富度及其蛋白質異構物多樣性。本研究分析49個插入玉米基因區之Ds-like轉位子，顯示多數Ds-like轉位子插入隱子區並構成隱子一部分，亦有Ds-like轉位子插入顯子區後成為新的隱子；分析玉米轉錄體資料庫，發現在cDNA中包含Ds-like訊息者多位於UTR，有2例顯示Ds-like插入隱子區後造成顯子化現象，而Ds1轉位子插入玉米GRMZM2G085600基因第5隱子之衍生之蛋白質異構產物，分析其序列包含2個新增活性位點。據此，玉米基因中找到Ac/Ds轉位子系統之顯子化且產生新增活性位點之實例，呈現轉位子顯子化對蛋白體功能性豐富度之貢獻。

關鍵字

Ds1轉位子；選擇性剪接；顯子化

並列摘要

An intronic transposable elements (TE) which provides splice site may lead to alternative splicing or exonization. For a single insertion event, Ds1 transposon could offer 3 splice donors and 2 splice acceptors (yield 11 transcripts and protein isoforms) while Ds element could offer the maximum of 4 splice donors (yield 4 transcripts and protein isoforms). Previous studies showed that both of Ds and Ds1 exonization could increase transcripts' and proteins' sequence diversity by incorporating the intron sequences with different reading frame. In this study, 49 maize genes which contain Ds-like (Ds family) sequence are investigated. The annotation and transcripts of these genes indicated that 44 Ds-like elements were inserting within introns and most of them became part of the introns. Besides, 3 Ds-like elements insert to exon regions and 2 Ds-like elements insert to untranslated regions. One Ds-like elements which insert to the 5th intron of GRMZM2G085600 resulted in exonized transcripts and yielding 2 new functional profiles. Based on our research, exonization could be considered one of the reasons in the evolution of plant proteome complexity.

並列關鍵字

Ds1 transposon ； Alternative splicing ； Exonization

國際替代計量

轉位子Ds1顯子化提供玉米基因轉錄及蛋白衍生體之新功能訊息

全文下載

主題瀏覽