The hepatitis C virus RNA 3′-untranslated region strongly enhances translation directed by the internal ribosome entry site
The hepatitis C virus RNA 3′-untranslated region strongly enhances translation directed by the internal ribosome entry site
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DOI：
10.1128/jvi.00675-06
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发表时间：
2006-12-01
影响因子：
5.4
通讯作者：
Niepmann, Michael
中科院分区：
文献类型：
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作者：
Song, Yutong;Friebe, Peter;Niepmann, Michael
丙型肝炎病毒（HCV）的正链RNA基因组两侧是5 '和3'非翻译区（UTR）。病毒RNA的翻译由5 '-UTR中的内部核糖体进入位点（IRES）指导，并且随后的病毒RNA复制需要3'-UTR和5 '-UTR中的序列。在本研究中，我们解决了先前关于3 '-UTR对于RNA翻译的可能功能的相互矛盾的报道，发现报告构建体设计是测试3'-UTR功能的实验中的重要参数。HCV 3 '-UTR的翻译增强子功能仅在转染具有精确3'末端的3 '-UTR的单顺反子报告RNA或完整RNA基因组后检测到。3 '-UTR在人肝癌细胞系中强烈刺激HCV IRES依赖性翻译，但在非肝细胞系中仅微弱刺激。高度保守的3' X区的可变区、多聚（U中心点C）区和最3'末端茎环I对翻译增强有显著贡献，而3' X区的茎环2和3仅在较小程度上参与。因此，用于翻译增强和启动HCV 3 '-UTR中RNA负链合成的信号部分重叠，支持这些序列沿着病毒因子以及可能的细胞因子一起可能参与RNA 3'-5 '末端相互作用以及转换的想法翻译和RNA复制。
The positive-strand RNA genome of the hepatitis C virus (HCV) is flanked by 5'- and 3'-untranslated regions (UTRs). Translation of the viral RNA is directed by the internal ribosome entry site (IRES) in the 5'-UTR, and subsequent viral RNA replication requires sequences in the 3'-UTR and in the 5'-UTR. Addressing previous conflicting reports on a possible function of the 3'-UTR for RNA translation in this study, we found that reporter construct design is an important parameter in experiments testing 3'-UTR function. A translation enhancer function of the HCV 3'-UTR was detected only after transfection of monocistronic reporter RNAs or complete RNA genomes having a 3'-UTR with a precise 3' terminus. The 3'-UTR strongly stimulates HCV IRES-dependent translation in human hepatoma cell lines but only weakly in nonliver cell lines. The variable region, the poly(U center dot C) tract, and the most 3' terminal stem-loop I of the highly conserved 3' X region contribute significantly to translation enhancement, whereas stem-loops 2 and 3 of the 3' X region are involved only to a minor extent. Thus, the signals for translation enhancement and for the initiation of RNA minus-strand synthesis in the HCV 3'-UTR partially overlap, supporting the idea that these sequences along with viral and possibly also cellular factors may be involved in an RNA 3'-5' end interaction and a switch between translation and RNA replication.