Functional requirements of the yellow fever virus capsid protein
Functional requirements of the yellow fever virus capsid protein
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DOI：
10.1128/jvi.02120-06
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发表时间：
2007-06-01
影响因子：
5.4
通讯作者：
Kuhn, Richard J.
中科院分区：
文献类型：
--
作者：
Patkar, Chinmay G.;Jones, Christopher T.;Kuhn, Richard J.
尽管已知黄病毒衣壳蛋白对于基因组包装和感染性颗粒的形成是必需的，但二聚体衣壳蛋白对于病毒组装/分解的最低要求尚未被表征。通过使用反式包装系统，通过使用辛德比斯病毒辅助构建体提供 YFV 结构蛋白，将黄热病病毒 (YFV) 复制子包装成假感染性颗粒，对 YFV 衣壳蛋白 (YFC) 内的功能元件进行了表征。分析了 YFC 的各种 Nand C 端截断、内部缺失和点突变，以确定它们包装 YFV 复制子的能力。与之前关于蜱传脑炎病毒衣壳蛋白的报道一致，YFC 表现出显着的功能灵活性。 YFC 的 N 末端近 40 个残基可以被去除，同时保留包装复制子 RNA 的能力。此外，含有 C 末端约 27 个残基删除（包括 C 末端螺旋 4 完全删除）的 YFC 是有功能的。一般来说，YFC 中包含内部疏水序列的内部缺失的耐受程度较低。还分析了预计参与单体间相互作用的螺旋 4 残基的定点诱变，虽然单个突变不影响包装，但具有亮氨酸 81 和缬氨酸 88 双突变的 YFC 是无功能的。还分析了 YFC 突变对 M 感染活力的影响，这些结果与使用复制子包装系统获得的结果相似，从而强调了 YFC 在其功能要求方面的灵活性。
Although it is known that the flavivirus capsid protein is essential for genome packaging and formation of infectious particles, the minimal requirements of the dimeric capsid protein for virus assembly/disassembly have not been characterized. By use of a trans-packaging system that involved packaging a yellow fever virus (YFV) replicon into pseudo-infectious particles by supplying the YFV structural proteins using a Sindbis virus helper construct, the functional elements within the YFV capsid protein (YFC) were characterized. Various Nand C-terminal truncations, internal deletions, and point mutations of YFC were analyzed for their ability to package the YFV replicon. Consistent with previous reports on the tick-borne encephalitis virus capsid protein, YFC demonstrates remarkable functional flexibility. Nearly 40 residues of YFC could be removed from the N terminus while the ability to package replicon RNA was retained. Additionally, YFC containing a deletion of approximately 27 residues of the C terminus, including a complete deletion of C-terminal helix 4, was functional. Internal deletions encompassing the internal hydrophobic sequence in YFC were, in general, tolerated to a lesser extent. Site-directed mutagenesis of helix 4 residues predicted to be involved in intermonomeric interactions were also analyzed, and although single mutations did not affect packaging, a YFC with the double mutation of leucine 81 and valine 88 was nonfunctional. The effects of mutations in YFC on the viability of M infection were also analyzed, and these results were similar to those obtained using the replicon packaging system, thus underscoring the flexibility of YFC with respect to the requirements for its functioning.