據(jù)美國(guó)匹茲堡大學(xué)癌癥研究中心的科學(xué)家的研究發(fā)現(xiàn),，之前一直被當(dāng)作是“垃圾RNA(junk RNA)”的細(xì)胞內(nèi)小片段RNA實(shí)際上是一種非常穩(wěn)定的分子,，或許在細(xì)胞代謝過程中發(fā)揮重大作用,。
這項(xiàng)發(fā)現(xiàn)發(fā)表在上周Journal of Virology網(wǎng)絡(luò)版上，是首個(gè)對(duì)小分子RNA——unusually small RNAs(usRNAs)的研究,，usRNA或?qū)⒊蔀橐环N新型的用于疾病診斷的生物標(biāo)記物或新的治療靶點(diǎn),。
近些年，科學(xué)家發(fā)現(xiàn)的小RNA一般長(zhǎng)度都超過20個(gè)核苷酸,。而在該研究中,，研究人員發(fā)現(xiàn)，長(zhǎng)度僅為15個(gè)核苷酸的RNA實(shí)際上是一種可以在不同組織中生成小分子RNA,，這類RNA非常穩(wěn)定,，并且重復(fù)性高，具有可再生能力,，所表現(xiàn)出多樣性遠(yuǎn)遠(yuǎn)超過所有其它的長(zhǎng)片段的RNA,。
研究人員利用的是卡波西肉瘤相關(guān)的皰疹病毒(Kaposi sarcoma-associated herpesvirus),，這種病毒所產(chǎn)生的usRNA能夠控制人體蛋白質(zhì)的產(chǎn)生。研究人員利用計(jì)算機(jī)技術(shù)以及實(shí)驗(yàn)工具對(duì)usRNAs進(jìn)一步研究發(fā)現(xiàn),，這類約只有15個(gè)核苷酸長(zhǎng)度的RNA有些有趣的特征,。許多usRNA能與參與小RNA調(diào)節(jié)通路的蛋白質(zhì)相互作用；一些usRNA鏈的一個(gè)末端具有高特異性的核苷酸,。
這項(xiàng)研究表明，usRNA參與了細(xì)胞的生物學(xué)過程,。Dr. John強(qiáng)調(diào),，這類小RNA或?qū)⒊蔀樵\斷疾病有用的工具，因此有必要對(duì)其進(jìn)行深入研究,。（生物谷Bioon.com）
生物谷推薦原始出處：
J. Virol. doi:10.1128/JVI.01325-09
Characterization of viral and human RNAs smaller than canonical microRNAs
Zhihua Li, Sang Woo Kim, Yuefeng Lin, Patrick S. Moore, Yuan Chang, and Bino John
University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA; Molecular Virology Program, Hillman Cancer Center, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
Recently identified small (20 to 40 bases) RNAs such as microRNAs (miRNAs) and endogenous siRNAs participate in important cellular pathways. In this report, we systematically characterize several novel features of human and viral RNA products smaller than miRNAs. We find that Kaposi sarcoma-associated herpesvirus K12-1 miRNA (23 bases), associates with a distinct, unusually small (17 bases) RNA (usRNA) that can effectively downregulate a K12-1 miRNA target, human RAD21, suggesting that stable degradation-like products may also contribute to gene regulation. High-throughput sequencing reveals a diverse set of human miRNA-derived usRNAs and other non-miRNA-derived usRNAs. Human miRNA-derived usRNAs preferentially match to 5' ends of miRNAs, and are also more likely to associate with the siRNA effector protein Ago2, than Ago1. Many non-miRNA-derived usRNAs associate with Ago proteins and also frequently contain C-rich 3'-specific motifs that are overrepresented in comparison to piRNAs and TSSa-RNAs. We postulate that approximately 30% of usRNAs could have evolved to participate in biological processes including gene-silencing.
