The tRNA-like structure of Turnip yellow mosaic virus RNA is a 3′-translational enhancer
The tRNA-like structure of Turnip yellow mosaic virus RNA is a 3′-translational enhancer
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DOI：
10.1016/j.virol.2003.10.023
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发表时间：
2004-03-30
期刊：
影响因子：
3.7
通讯作者：
Dreher, TW
中科院分区：
文献类型：
--
作者：
Matsuda, D;Dreher, TW
许多正链RNA病毒基因组缺乏poly（A）尾，poly（A）尾是细胞mRNA的特征，并促进顺式翻译。预期这些基因组的3'非翻译区（UTR）提供与多聚腺苷酸尾类似的增强免疫的性质，然而3'序列的大量变化表明这是以一系列方式实现的。我们已经鉴定了存在于芜菁黄花叶病毒（TYMV）RNA的3' UTR中的翻译增强子，使用具有通用5'序列的荧光素酶报告RNA转染到植物细胞中。包含tRNA样结构（TLS）和上游假结（UPSK）的3'末端109个核苷酸与5'-帽协同作用以增强翻译，在稳定RNA方面具有较小的贡献。最大增强需要RNA能够氨酰化，但天然缬氨酸或工程化甲硫氨酸都是可接受的。降低翻译延伸因子eEF 1A亲和力（但也降低氨酰化效率）的突变强烈降低翻译增强，表明eEF 1A在机制上参与其中。UPSK似乎作为一个重要的，但非特异性，间隔元件，确保正确的功能TLS的介绍。我们的研究发现了一种新型的翻译增强子和植物病毒TLS的新作用。(C)2004年由Elsevier lnc出版。
Many positive stand RNA viral genomes lack the poly(A) tail that is characteristic of cellular mRNAs and that promotes translation in cis. The 3' untranslated regions (UTRs) of such genomes are expected to provide similar translation-enhancing properties as a poly(A) tail, yet the great variety of 3' sequences suggests that this is accomplished in a range of ways. We have identified a translational enhancer present in the 3' UTR of Turnip yellow mosaic virus (TYMV) RNA using luciferase reporter RNAs with generic 5' sequences transfected into plant cells. The 3' terminal 109 nucleotides comprising the tRNA-like structure (TLS) and an upstream pseudoknot (UPSK) act in synergy with a 5'-cap to enhance translation, with a minor contribution in stabilizing the RNA. Maximum enhancement requires that the RNA be capable of aminoacylation, but either the native valine or engineered methionine is acceptable. Mutations that decrease the affinity for translation elongation factor eEF1A (but also diminish aminoacylation efficiency) strongly decrease translational enhancement, suggesting that eEF1A is mechanistically involved. The UPSK seems to act as an important, though nonspecific, spacer element ensuring proper presentation of a functional TLS. Our studies have uncovered a novel type of translational enhancer and a new role for a plant viral TLS. (C) 2004 Published by Elsevier lnc.