Control of translation by the 5′- and 3′-terminal regions of the dengue virus genome
Control of translation by the 5′- and 3′-terminal regions of the dengue virus genome
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DOI：
10.1128/jvi.79.13.8303-8315.2005
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发表时间：
2005-07-01
影响因子：
5.4
通讯作者：
Dreher, TW
中科院分区：
文献类型：
--
作者：
Chiu, WW;Kinney, RM;Dreher, TW
黄病毒（如登革病毒，DEN）的基因组RNA像细胞mRNA一样具有5' m(7)GpppN帽结构，但缺乏3'多聚（A）尾。我们通过将荧光素酶报告mRNA转染到Vero细胞中，研究了登革病毒2型血清型基因组5'和3'末端区域对翻译表达的贡献。DCLD RNA包含整个登革病毒5'和3'非翻译区（UTR），以及与荧光素酶报告基因融合的衣壳编码区的前36个密码子。加帽的DCLD RNA在Vero细胞中的翻译效率与加帽的GLGpA RNA相同，GLGpA RNA是一种具有来自高表达的α - 珠蛋白mRNA的UTR和72个残基的多聚（A）尾的报告基因。具有来自西尼罗河病毒和辛德毕斯病毒调控序列的类似报告RNA也能强烈表达。尽管加帽的DCLD RNA的表达效率比其无帽形式高得多，但无帽的DCLD RNA的翻译效率比具有来自珠蛋白mRNA的UTR的无帽RNA高6到12倍。5'帽和登革病毒3' UTR是DCLD RNA翻译效率的主要来源，并且它们在增强翻译方面具有协同作用。登革病毒3' UTR增加了mRNA的稳定性，尽管这种效应比翻译效率的增强要弱得多。因此，登革病毒3' UTR具有类似于多聚（A）尾的翻译调控特性。对于具有珠蛋白或登革病毒5'序列的RNA都观察到了其翻译增强效应，这表明病毒5'和3'序列之间没有相互依赖性。缺失研究表明，登革病毒3' UTR提供的翻译增强归因于几个保守元件以及紧邻终止密码子的一个非保守结构域的累积贡献。其中一个保守元件是保守序列（CS）CSI，它与登革病毒多聚蛋白开放阅读框5'端存在的cCS1互补。CS1和cCS1之间的互补性对于有效翻译不是必需的。
The genomic RNAs of flaviviruses such as dengue virus (DEN) have a 5' m(7)GpppN cap like those of cellular mRNAs but lack a 3' poly(A) tail. We have studied the contributions to translational expression of 5% and 3'-terminal regions of the DEN serotype 2 genome by using luciferase reporter mRNAs transfected into Vero cells. DCLD RNA contained the entire DEN 5' and 3' untranslated regions (UTRs), as well as the first 36 codons of the capsid coding region fused to the luciferase reporter gene. Capped DCLD RNA was as efficiently translated in Vero cells as capped GLGpA RNA, a reporter with UTRs from the highly expressed alpha-globin mRNA and a 72-residue poly(A) tail. Analogous reporter RNAs with regulatory sequences from West Nile and Sindbis viruses were also strongly expressed. Although capped DCLD RNA was expressed much more efficiently than its uncapped form, uncapped DCLD RNA was translated 6 to 12 times more efficiently than uncapped RNAs with UTRs from globin mRNA. The 5' cap and DEN 3' UTR were the main sources of the translational efficiency of DCLD RNA, and they acted synergistically in enhancing translation. The DEN 3' UTR increased mRNA stability, although this effect was considerably weaker than the enhancement of translational efficiency. The DEN 3' UTR thus has translational regulatory properties similar to those of a poly(A) tail. Its translation-enhancing effect was observed for RNAs with globin or DEN 5' sequences, indicating no codependency between viral 5' and 3' sequences. Deletion studies showed that translational enhancement provided by the DEN 3' UTR is attributable to the cumulative contributions of several conserved elements, as well as a nonconserved domain adjacent to the stop codon. One of the conserved elements was the conserved sequence (CS) CSI that is complementary to cCS1 present in the 5' end of the DEN polyprotein open reading frame. Complementarity between CS1 and cCS1 was not required for efficient translation.