A Ribosome-Binding, 3′ Translational Enhancer Has a T-Shaped Structure and Engages in a Long-Distance RNA-RNA Interaction
A Ribosome-Binding, 3′ Translational Enhancer Has a T-Shaped Structure and Engages in a Long-Distance RNA-RNA Interaction
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DOI：
10.1128/jvi.00677-12
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发表时间：
2012-09-01
影响因子：
5.4
通讯作者：
Simon, Anne E.
中科院分区：
文献类型：
--
作者：
Gao, Feng;Kasprzak, Wojciech;Simon, Anne E.
许多植物 RNA 病毒的 3' 非翻译区 (3' UTR) 中含有增强翻译的元件。豌豆花叶病毒 (PEMV) 的 PTE（黍花叶病毒样翻译增强子）与真核起始因子 4E (eIF4E) 结合，但这如何影响 5' 端的翻译尚不清楚。我们在 PEMV PTE 的上游发现了一个三路分支元件，它与编码序列发夹进行长距离接吻环相互作用，这对于报告基因构建体的翻译和体内病毒基因组的积累至关重要。长距离相互作用的丧失比相邻 PTE 的消除更有害，这表明除了将 PTE 重新定位到 5' 端之外，RNA-RNA 相互作用还支持其他翻译功能。通过分子模型和分子动力学预测支链元件会形成类似于芜菁皱纹病毒（TCV）的核糖体结合TSS的T形结构（TSS）。 PEMV 元件与植物 80S 核糖体结合，K-d（解离常数）为 0.52 μM，与 60S 亚基结合，K-d 为 0.30 μM。与 TCV TSS 不同，PEMV 元件还结合 40S 亚基（K-d，0.36 μM）。抑制翻译的元件的突变会减少核糖体结合或 RNA-RNA 相互作用，这表明核糖体结合对于功能很重要。这种新颖的多功能元件被命名为 kl-TSS（接吻环 T 形结构），以区别于 TCV TSS。 kl-TSS具有与大多数PTE型元件的上部部分保守的序列和结构特征，除了PEMV PTE之外，其可以参与类似的长距离RNA-RNA相互作用。
Many plant RNA viruses contain elements in their 3' untranslated regions (3' UTRs) that enhance translation. The PTE (Panicum mosaic virus-like translational enhancer) of Pea enation mosaic virus (PEMV) binds to eukaryotic initiation factor 4E (eIF4E), but how this affects translation from the 5' end is unknown. We have discovered a three-way branched element just upstream of the PEMV PTE that engages in a long-distance kissing-loop interaction with a coding sequence hairpin that is critical for the translation of a reporter construct and the accumulation of the viral genome in vivo. Loss of the long-distance interaction was more detrimental than elimination of the adjacent PTE, indicating that the RNA-RNA interaction supports additional translation functions besides relocating the PTE to the 5' end. The branched element is predicted by molecular modeling and molecular dynamics to form a T-shaped structure (TSS) similar to the ribosome-binding TSS of Turnip crinkle virus (TCV). The PEMV element binds to plant 80S ribosomes with a K-d (dissociation constant) of 0.52 mu M and to 60S subunits with a K-d of 0.30 mu M. Unlike the TCV TSS, the PEMV element also binds 40S subunits (K-d, 0.36 mu M). Mutations in the element that suppressed translation reduced either ribosome binding or the RNA-RNA interaction, suggesting that ribosome binding is important for function. This novel, multifunctional element is designated a kl-TSS (kissing-loop T-shaped structure) to distinguish it from the TCV TSS. The kl-TSS has sequence and structural features conserved with the upper portion of most PTE-type elements, which, with the exception of the PEMV PTE, can engage in similar long-distance RNA-RNA interactions.