Noncanonical repression of translation initiation through small RNA recruitment of the RNA chaperone Hfq
Noncanonical repression of translation initiation through small RNA recruitment of the RNA chaperone Hfq
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DOI：
10.1101/gad.182493.111
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发表时间：
2012-04-01
影响因子：
10.5
通讯作者：
Masse, Eric
中科院分区：
文献类型：
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作者：
Desnoyers, Guillaume;Masse, Eric
已知RNA伴侣Hfq主要帮助小调节RNA（sRNA）与靶mRNA相互作用以阻断起始核糖体。在该模型中，sRNA直接与起始30 S核糖体亚基竞争，而Hfq仅起间接作用，允许最佳sRNA-mRNA配对。在这里，我们报告说，Hfq的募集sRNA，斑点42，结合到一个精确的AU丰富的区域附近的翻译起始区（TIR）的sdhC mRNA和竞争直接与30 S核糖体亚基。我们表明，sRNA Spot 42结合sdhC太远上游的TIR直接抑制翻译起始在体外和体内。与sRNA调控的经典模型相反，这表明了一种新的机制，其中Hfq直接参与靶mRNA的翻译抑制，并且sRNA仅作为募集因子。
The RNA chaperone Hfq is mostly known to help small regulatory RNAs (sRNAs) interact with target mRNAs to block initiating ribosomes. In this model, whereas the sRNA is directly competing with initiating 30S ribosomal subunits, Hfq plays only an indirect role, allowing optimal sRNA-mRNA pairing. Here we report that Hfq is recruited by a sRNA, Spot42, to bind to a precise AU-rich region in the vicinity of the translation initiation region (TIR) of sdhC mRNA and competes directly with 30S ribosomal subunits. We show that the sRNA Spot42 binds sdhC too far upstream of the TIR to directly repress translation initiation in vitro and in vivo. Contrary to the canonical model of sRNA regulation, this suggests a new mechanism where Hfq is directly involved in the translational repression of the target mRNA and where the sRNA acts only as a recruitment factor.