轉(zhuǎn)位因子（transposable elements,，TEs）在植物和動物的基因組中到處存在,，但是科學(xué)家還不是很清楚基因組如何適應(yīng)成百甚至數(shù)千新的轉(zhuǎn)位因子的快速插入。
在最近的一項研究中,，喬治亞大學(xué)的植物生物學(xué)家首次證實這些突然的插入對水稻的影響,。
這項研究一驚奇的發(fā)現(xiàn)是：轉(zhuǎn)位因子對宿主的影響似乎是中性的。此外,，研究人員表示,，遺傳多樣性，是由大量TE的快速插入造成的,。這種意想不到的方式實際上對植物來說是有益的,。
這項發(fā)現(xiàn)是全新的，也確實是很讓人興奮的,。該研究的負(fù)責(zé)人Susan Wessler介紹說,，他們所研究的TE避開了在外顯子區(qū)域的插入。但是更重要的一點是,，像水稻這類自我授粉的植物,，TE的闖入可能是它們在面對不斷變化的環(huán)境，一種快速產(chǎn)生遺傳多樣性的重要方式,。
這項研究結(jié)果發(fā)布在Nature的在線版本上,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 461, 1130-1134 (22 October 2009) | doi:10.1038/nature08479
Unexpected consequences of a sudden and massive transposon amplification on rice gene expression
Ken Naito1,2, Feng Zhang1,3, Takuji Tsukiyama2, Hiroki Saito2, C. Nathan Hancock1, Aaron O. Richardson1, Yutaka Okumoto2, Takatoshi Tanisaka2 & Susan R. Wessler1
1.Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
2.Division of Agronomy and Horticulture Science, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
3.Present address: Department of Genetics, Cell Biology and Development, University of Minnesota, Minnesota 55455, USA.
Correspondence to: Takatoshi Tanisaka2Susan R. Wessler1 Correspondence and requests for materials should be addressed to S.R.W. or T.Tanisaka.
High-copy-number transposable elements comprise the majority of eukaryotic genomes where they are major contributors to gene and genome evolution1. However, it remains unclear how a host genome can survive a rapid burst of hundreds or thousands of insertions because such bursts are exceedingly rare in nature and therefore difficult to observe in real time2. In a previous study we reported that in a few rice strains the DNA transposon mPing was increasing its copy number by 40 per plant per generation3. Here we exploit the completely sequenced rice genome to determine 1,664 insertion sites using high-throughput sequencing of 24 individual rice plants and assess the impact of insertion on the expression of 710 genes by comparative microarray analysis. We find that the vast majority of transposable element insertions either upregulate or have no detectable effect on gene transcription. This modest impact reflects a surprising avoidance of exon insertions by mPing and a preference for insertion into 5' flanking sequences of genes. Furthermore, we document the generation of new regulatory networks by a subset of mPing insertions that render adjacent genes stress inducible. As such, this study provides evidence for models first proposed previously4, 5, 6 for the involvement of transposable elements and other repetitive sequences in genome restructuring and gene regulation.
