生物谷：研究人員在8月在線出版的《自然—方法學(xué)》上報告,，通過基因工程合成的一種抑制劑能夠吞食哺乳類動物細(xì)胞中的小分子RNA。抑制小分子RNA的活性有助于深入認(rèn)識它們在正常發(fā)育和疾病中的功能,。
與更長的信使RNA不一樣，小分子RNA沒有含有制造蛋白質(zhì)的信息,，它只擁有21個核苷酸,，但這種序列卻能調(diào)控信使RNA的表達(dá)。小分子RNA的序列與其目標(biāo)物——信使RNA的序列部分相連,，結(jié)果令信使RNA的或是分解或是蛋白質(zhì)轉(zhuǎn)錄的過程被中止,。科學(xué)家們早已將某種小分子RNA的過度表達(dá)與癌癥和其他疾病聯(lián)系起來,，因此,，深入認(rèn)識這些小分子RNA的功能非常重要。
Philip Sharp和同事研制出一種可目標(biāo)阻斷小分子RNA的特殊工具,，這個工具的基本原理是：用一種補(bǔ)充的假序列來吞食全部的小分子RNA,，讓信使RNA不受阻擋地表達(dá)出蛋白質(zhì)。與以前描述的化學(xué)合成小分子RNA抑制劑的方法相反,，這些吞食小分子RNA的“海綿”是通過基因工程編碼的,，它們提供給細(xì)胞的信息或者是形成一種質(zhì)粒，或者是被整合進(jìn)某個細(xì)胞的序列,。新工作提供了在一個更高水平上控制細(xì)胞中小分子RNA水平的方法,，讓研究人員能夠在特定細(xì)胞或組織中研究小分子RNA的功能。（科學(xué)時報）
原始出處:
Published online: 12 August 2007; | doi:10.1038/nmeth1079
MicroRNA sponges: competitive inhibitors of small RNAs in mammalian cells
Margaret S Ebert, Joel R Neilson & Phillip A Sharp
Center for Cancer Research, E17-529B Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Correspondence should be addressed to Phillip A Sharp [email protected]
MicroRNAs are predicted to regulate thousands of mammalian genes, but relatively few targets have been experimentally validated and few microRNA loss-of-function phenotypes have been assigned. As an alternative to chemically modified antisense oligonucleotides, we developed microRNA inhibitors that can be expressed in cells, as RNAs produced from transgenes. Termed 'microRNA sponges', these competitive inhibitors are transcripts expressed from strong promoters, containing multiple, tandem binding sites to a microRNA of interest. When vectors encoding these sponges are transiently transfected into cultured cells, sponges derepress microRNA targets at least as strongly as chemically modified antisense oligonucleotides. They specifically inhibit microRNAs with a complementary heptameric seed, such that a single sponge can be used to block an entire microRNA seed family. RNA polymerase II promoter (Pol II)-driven sponges contain a fluorescence reporter gene for identification and sorting of sponge-treated cells. We envision the use of stably expressed sponges in animal models of disease and development.
