Sullivan Christopher S, Ganem Don
G. W. Hooper Research Foundation, University of California, San Francisco, 513 Parnassus Ave., HSW 1501, Box 0552, San Francisco, CA 94143-0552, USA.
J Virol. 2005 Jun;79(12):7371-9. doi: 10.1128/JVI.79.12.7371-7379.2005.
Nodamura virus (NoV) is a small RNA virus that is infectious for insect and mammalian hosts. We have developed a highly sensitive assay of RNA interference (RNAi) in mammalian cells that shows that the NoV B2 protein functions as an inhibitor of RNAi triggered by either short hairpin RNAs or small interfering RNAs. In the cell, NoV B2 binds to pre-Dicer substrate RNA and RNA-induced silencing complex (RISC)-processed RNAs and inhibits the Dicer cleavage reaction and, potentially, one or more post-Dicer activities. In vitro, NoV B2 inhibits Dicer-mediated RNA cleavage in the absence of any other host factors and specifically binds double-stranded RNAs corresponding in structure to Dicer substrates and products. Its abilities to bind to Dicer precursor and post-Dicer RISC-processed RNAs suggest a mechanism of inhibition that is unique among known viral inhibitors of RNAi.
诺达木拉病毒（NoV）是一种小型RNA病毒，可感染昆虫和哺乳动物宿主。我们在哺乳动物细胞中开发了一种高度灵敏的RNA干扰（RNAi）检测方法，结果表明NoV B2蛋白可作为短发夹RNA或小干扰RNA引发的RNAi的抑制剂。在细胞中，NoV B2与Dicer酶切前体RNA和RNA诱导沉默复合体（RISC）加工后的RNA结合，抑制Dicer酶切反应，并可能抑制一种或多种Dicer酶切后的活性。在体外，NoV B2在没有任何其他宿主因子的情况下抑制Dicer介导的RNA切割，并特异性结合结构上与Dicer底物和产物相对应的双链RNA。它与Dicer前体和Dicer酶切后RISC加工的RNA结合的能力表明了一种抑制机制，这在已知的RNAi病毒抑制剂中是独特的。
