Distinct RNA elements confer specificity to flavivirus RNA cap methylation events
Distinct RNA elements confer specificity to flavivirus RNA cap methylation events
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DOI：
10.1128/jvi.02455-06
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发表时间：
2007-05-01
影响因子：
5.4
通讯作者：
Shi, Pei-Yong
中科院分区：
文献类型：
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作者：
Dong, Hongping;Ray, Debashish;Shi, Pei-Yong
哈维病毒正义RNA基因组的5'端含有1型帽（m（7）GpppAmG），随后是保守的茎环结构。我们报道了来自四种黄病毒血清复合物的非结构蛋白5（NS 5）通过识别病毒RNA的5'末端特异性地甲基化帽。帽上鸟嘌呤N-7和第一个转录核苷酸上核糖2 '-OH的甲基化需要不同的RNA元件。在西尼罗河病毒（WNV）模型中，N-7帽甲基化需要在第二和第三位置处的特定核苷酸以及5'茎环结构;相反，2'-OH核糖甲基化需要在第一和第二位置处的特定核苷酸，其中最小5'病毒RNA为20个核苷酸。帽类似物GpppA和m（7）GpppA不是WNV甲基转移酶的活性底物。使用Gppp-和m（7）Gppp-终止的RNA的足迹实验表明，RNA底物的5'末端在顺序甲基化反应期间与NS 5相互作用。靶向VNV基因组前20个核苷酸的反义寡聚体可以抑制Cap甲基化。病毒RNA特异性帽甲基化表明甲基转移酶是黄病毒药物发现的新靶点。
The 5' end of the Havivirus plus-sense RNA genome contains a type 1 cap (m(7) GpppAmG), followed by a conserved stem-loop structure. We report that nonstructural protein 5 (NS5) from four serocomplexes of flaviviruses specifically methylates the cap through recognition of the 5' terminus of viral RNA. Distinct RNA elements are required for the methylations at guanine N-7 on the cap and ribose 2'-OH on the first transcribed nucleotide. In a West Nile virus (WNV) model, N-7 cap methylation requires specific nucleotides at the second and third positions and a 5' stem-loop structure; in contrast, 2'-OH ribose methylation requires specific nucleotides at the first and second positions, with a minimum 5' viral RNA of 20 nucleotides. The cap analogues GpppA and m(7) GpppA are not active substrates for WNV methytransferase. Footprinting experiments using Gppp- and m(7) Gppp-terminated RNAs suggest that the 5' termini of RNA substrates interact with NS5 during the sequential methylation reactions. Cap methylations could be inhibited by an antisense oligomer targeting the first 20 nucleotides of VNV genome. The viral RNA-specific cap methylation suggests methyltransferase as a novel target for flavivirus drug discovery.