Kraynack Bryan A, Baker Brenda F
ISIS Pharmaceuticals, Carlsbad Research Center, 1896 Rutherford Road, Carlsbad, CA 92008, USA.
RNA. 2006 Jan;12(1):163-76. doi: 10.1261/rna.2150806. Epub 2005 Nov 21.
RNA interference (RNAi) is a process by which short interfering RNAs (siRNAs) direct the degradation of complementary single-strand RNAs. In this study, we investigated the effects of full-strand phosphorothioate (PS) backbone and 2'-O-methyl (2'-OMe) sugar modifications on RNAi-mediated silencing. In contrast to previous reports, we have identified active siRNA duplexes containing full 2'-OMe-modified sense strands that display comparable activity to the unmodified analog of similar sequence. The structure of these modified siRNAs is the predominant determinant of their activity, with sequence and backbone composition being secondary. We further show, by using biotin-tagged siRNAs and affinity-tagged hAgo2/eIF2C2, that activity of siRNA duplexes containing full 2'-OMe substitutions in the sense strand is mediated by the RNA-induced silencing complex (RISC) and that strand-specific loading (or binding) to hAgo2 may be modulated through selective incorporation of these modifications.
RNA干扰（RNAi）是一个过程，通过该过程，短干扰RNA（siRNA）指导互补单链RNA的降解。在本研究中，我们研究了全链硫代磷酸酯（PS）骨架和2'-O-甲基（2'-OMe）糖修饰对RNAi介导的沉默作用的影响。与之前的报道相反，我们鉴定出了活性siRNA双链体，其正义链完全由2'-OMe修饰，与相似序列的未修饰类似物表现出相当的活性。这些修饰的siRNA的结构是其活性的主要决定因素，序列和骨架组成是次要因素。我们进一步表明，通过使用生物素标记的siRNA和亲和标记的hAgo2/eIF2C2，正义链中含有完全2'-OMe取代的siRNA双链体的活性由RNA诱导沉默复合体（RISC）介导，并且通过选择性掺入这些修饰，可能会调节其与hAgo2的链特异性装载（或结合）。
