HIV-1 RRE RNA acts as an RNA silencing suppressor by competing with TRBP-bound siRNAs
HIV-1 RRE RNA acts as an RNA silencing suppressor by competing with TRBP-bound siRNAs
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DOI：
10.1080/15476286.2015.1014759
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发表时间：
2015-01-01
期刊：
影响因子：
4.1
通讯作者：
Gatignol, Anne
中科院分区：
文献类型：
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作者：
Daniels, Sylvanne M.;Sinck, Lucile;Gatignol, Anne
已经报道了由哺乳动物病毒表达的几种蛋白质和RNA干扰RNA干扰（RNAi）活性。我们研究了HIV-1编码的RNA元件反式激活反应（TAR）和Rev反应元件（RRE）改变RNAi的能力。基于microRNA let 7的测定显示RRE是RNAi活性的有效抑制剂，而TAR显示中度RNAi抑制。我们证明，RRE结合到TAR-RNA结合蛋白（TRBP），RNA诱导沉默复合物（RISC）的一个重要组成部分。TAR和RRE与TRBP的结合取代了小干扰（si）RNA与TRBP的结合。几个茎缺失的RRE突变体失去了抑制RNAi活性的能力，这与与siRNA-TRBP结合竞争能力降低相关。表达TAR和RRE限制性RNAi的慢病毒载体，但当Rev或GagPol共表达时，RNAi恢复。腺病毒受RNAi限制，并编码其自身的RNAi抑制子，即病毒相关（VA）RNA元件。RRE增强了野生型和VA缺陷型腺病毒的复制。我们的工作将RRE描述为一种新的RNAi抑制剂，其通过与siRNA竞争而不是通过破坏RISC来发挥作用。这种功能在与病毒蛋白共表达的慢病毒载体中被掩盖，因此不会影响它们在基因治疗中的应用。本研究中鉴定的RRE的有效RNAi抑制作用可用于增强用于溶瘤的RNAi限制性病毒（如腺病毒）的表达。
Several proteins and RNAs expressed by mammalian viruses have been reported to interfere with RNA interference (RNAi) activity. We investigated the ability of the HIV-1-encoded RNA elements Trans-Activation Response (TAR) and Rev-Response Element (RRE) to alter RNAi. MicroRNA let7-based assays showed that RRE is a potent suppressor of RNAi activity, while TAR displayed moderate RNAi suppression. We demonstrate that RRE binds to TAR-RNA Binding Protein (TRBP), an essential component of the RNA Induced Silencing Complex (RISC). The binding of TAR and RRE to TRBP displaces small interfering (si) RNAs from binding to TRBP. Several stem-deleted RRE mutants lost their ability to suppress RNAi activity, which correlated with a reduced ability to compete with siRNA-TRBP binding. A lentiviral vector expressing TAR and RRE restricted RNAi, but RNAi was restored when Rev or GagPol were coexpressed. Adenoviruses are restricted by RNAi and encode their own suppressors of RNAi, the Virus-Associated (VA) RNA elements. RRE enhanced the replication of wild-type and VA-deficient adenovirus. Our work describes RRE as a novel suppressor of RNAi that acts by competing with siRNAs rather than by disrupting the RISC. This function is masked in lentiviral vectors co-expressed with viral proteins and thus will not affect their use in gene therapy. The potent RNAi suppressive effects of RRE identified in this study could be used to enhance the expression of RNAi restricted viruses used in oncolysis such as adenoviruses.