真核生物已經(jīng)進(jìn)化出了復(fù)雜的機(jī)制,，通過蛋白感受器,、傳感器及作用因子的協(xié)同作用來進(jìn)行DNA雙鏈斷裂修復(fù)(DSBs),。
北京生命科學(xué)研究所的戚益軍等人研究發(fā)現(xiàn),，在擬南芥及人類細(xì)胞中,，DSB位點(diǎn)附近產(chǎn)生了大小約21個(gè)核苷酸的小RNAs,。研究人員把這些小RNAs稱作對(duì)DSB誘導(dǎo)的小RNAs有關(guān)的diRNAs,。相關(guān)論文發(fā)表在3月30日的Cell。
在擬南芥中,，diRNAs的產(chǎn)生需要PI3激酶ATR,，RNA合成酶IV(Pol IV)，以及Dicer樣蛋白,。這些蛋白及Pol V的突變會(huì)引起DSB修復(fù)效率顯著的降低,。
而且，在擬南芥中,，diRNAs是由Argonaute蛋白2(AGO2)招募來介導(dǎo)DSB的修復(fù),。在人類細(xì)胞中，敲除Dicer或Ago2同樣會(huì)降低DSB的修復(fù)效率,。
研究結(jié)果表明,，diRNAs介導(dǎo)的DSB修復(fù)在人類及植物中是保守的。
因此,，diRNAs很能是作為一個(gè)引導(dǎo)分子來指向染色體修飾,，或者是招募蛋白復(fù)合體到DSB位點(diǎn)來幫助修復(fù)。（生物谷Deepblue編譯）
doi: 10.1016/j.cell.2012.03.002
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A Role for Small RNAs in DNA Double-Strand Break Repair
Wei Wei, Zhaoqing Ba, Min Gao, Yang Wu, Yanting Ma, Simon Amiard, Charles I. White, Jannie Michaela Rendtlew Danielsen, Yun-Gui Yang, Yijun Qi .
Eukaryotes have evolved complex mechanisms to repair DNA double-strand breaks (DSBs) through coordinated actions of protein sensors, transducers, and effectors.Here we show that ～21-nucleotide small RNAs are produced from the sequences in the vicinity of DSB sites in Arabidopsis and in human cells. We refer to these as diRNAs for DSB-induced small RNAs.In Arabidopsis, the biogenesis of diRNAs requires the PI3 kinase ATR, RNA polymerase IV (Pol IV), and Dicer-like proteins. Mutations in these proteins as well as in Pol V cause significant reduction in DSB repair efficiency.In Arabidopsis, diRNAs are recruited by Argonaute 2 (AGO2) to mediate DSB repair. Knock down of Dicer or Ago2 in human cells reduces DSB repair.Our findings reveal a conserved function for small RNAs in the DSB repair pathway.We propose that diRNAs may function as guide molecules directing chro.
