Department of Hepatology and Gene Therapy, Center for Applied Medical Research (CIMA), University of Navarra, Pio XII 55. 31008 Pamplona, Spain.
Nucleic Acids Res. 2012 Jan;40(1):e8. doi: 10.1093/nar/gkr956. Epub 2011 Nov 15.
Inhibition of gene expression can be achieved with RNA interference (RNAi) or U1 small nuclear RNA-snRNA-interference (U1i). U1i is based on U1 inhibitors (U1in), U1 snRNA molecules modified to inhibit polyadenylation of a target pre-mRNA. In culture, we have shown that the combination of RNAi and U1i results in stronger inhibition of reporter or endogenous genes than that obtained using either of the techniques alone. We have now used these techniques to inhibit gene expression in mice. We show that U1ins can induce strong inhibition of the expression of target genes in vivo. Furthermore, combining U1i and RNAi results in synergistic inhibitions also in mice. This is shown for the inhibition of hepatitis B virus (HBV) sequences or endogenous Notch1. Surprisingly, inhibition obtained by combining a U1in and a RNAi mediator is higher than that obtained by combining two U1ins or two RNAi mediators. Our results suggest that RNAi and U1i cooperate by unknown mechanisms to result in synergistic inhibitions. Analysis of toxicity and specificity indicates that expression of U1i inhibitors is safe. Therefore, we believe that the combination of RNAi and U1i will be a good option to block damaging endogenous genes, HBV and other infectious agents in vivo.
基因表达的抑制可以通过 RNA 干扰（RNAi）或 U1 小核 RNA-snRNA 干扰（U1i）来实现。U1i 基于 U1 抑制剂（U1in），即经过修饰以抑制靶标 pre-mRNA 多聚腺苷酸化的 U1 snRNA 分子。在培养中，我们已经表明，与单独使用任何一种技术相比，RNAi 和 U1i 的组合可导致报告基因或内源性基因的抑制更强。我们现在已经在小鼠中使用这些技术来抑制基因表达。我们表明 U1in 可以在体内诱导靶基因的强烈抑制。此外，U1i 和 RNAi 的组合在小鼠中也会产生协同抑制。这在乙型肝炎病毒（HBV）序列或内源性 Notch1 的抑制中得到了证明。令人惊讶的是，通过组合使用 U1in 和 RNAi 介导物获得的抑制作用高于通过组合使用两个 U1in 或两个 RNAi 介导物获得的抑制作用。我们的结果表明，RNAi 和 U1i 通过未知机制协同作用，导致协同抑制。对毒性和特异性的分析表明，U1i 抑制剂的表达是安全的。因此，我们认为 RNAi 和 U1i 的组合将是阻止体内有害内源性基因、HBV 和其他传染性病原体的一个很好的选择。
