Novel cis-Acting Element within the Capsid-Coding Region Enhances Flavivirus Viral-RNA Replication by Regulating Genome Cyclization
Novel cis-Acting Element within the Capsid-Coding Region Enhances Flavivirus Viral-RNA Replication by Regulating Genome Cyclization
复制标题
衣壳编码区内的新型顺式作用元件通过调节基因组环化增强黄病毒RNA复制
DOI：
10.1128/jvi.00243-13
复制
发表时间：
2013-06-01
影响因子：
5.4
通讯作者：
Qin, Cheng-Feng
中科院分区：
文献类型：
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作者：
Liu, Zhong-Yu;Li, Xiao-Feng;Qin, Cheng-Feng
病毒基因组RNA（vRNA）中的顺式作用元件是RNA病毒翻译、复制和/或降解所必需的。本研究在蚊媒黄病毒衣壳蛋白编码区发现了一个新的保守的顺式作用元件。结构预测和生化分析表明，5′环化序列（5′CS）假结（DCS-PK）元件下游具有三茎假结结构。使用登革热病毒作为模型，我们表明，DCS-PK增强vRNA复制，其功能取决于其二级结构和特定的一级序列。突变显示，高度保守的茎1和环2，参与潜在的环-螺旋相互作用，是至关重要的DCS-PK功能。预测的环1-茎3碱基三重相互作用对于DCS-PK的结构稳定性和功能是重要的。此外，DCS-PK的功能取决于其相对于5′CS的位置，并且DCS-PK的存在促进5′-3′ RNA复合物的形成。综上所述，我们的研究结果表明，顺式作用元件DCS-PK通过调节基因组环化增强vRNA复制，DCS-PK可能与其他顺式作用元件相互作用，形成功能性vRNA环化结构域，从而在黄病毒的生命周期和进化中发挥关键作用。
ABSTRACT cis-Acting elements in the viral genome RNA (vRNA) are essential for the translation, replication, and/or encapsidation of RNA viruses. In this study, a novel conserved cis-acting element was identified in the capsid-coding region of mosquito-borne flavivirus. The downstream of 5′ cyclization sequence (5′CS) pseudoknot (DCS-PK) element has a three-stem pseudoknot structure, as demonstrated by structure prediction and biochemical analysis. Using dengue virus as a model, we show that DCS-PK enhances vRNA replication and that its function depends on its secondary structure and specific primary sequence. Mutagenesis revealed that the highly conserved stem 1 and loop 2, which are involved in potential loop-helix interactions, are crucial for DCS-PK function. A predicted loop 1-stem 3 base triple interaction is important for the structural stability and function of DCS-PK. Moreover, the function of DCS-PK depends on its position relative to the 5′CS, and the presence of DCS-PK facilitates the formation of 5′-3′ RNA complexes. Taken together, our results reveal that the cis-acting element DCS-PK enhances vRNA replication by regulating genome cyclization, and DCS-PK might interplay with other cis-acting elements to form a functional vRNA cyclization domain, thus playing critical roles during the flavivirus life cycle and evolution.