Mendes Adriano, Vlok Marli, Short James R, Matsui Tsutomu, Dorrington Rosemary A
Department of Biochemistry and Microbiology, Rhodes University, PO Box 94, Grahamstown 6140, South Africa.
Department of Biochemistry and Microbiology, Rhodes University, PO Box 94, Grahamstown 6140, South Africa.
Virology. 2015 Feb;476:323-333. doi: 10.1016/j.virol.2014.12.026. Epub 2015 Jan 9.
Alphatetraviruses are small (+) ssRNA viruses with non-enveloped, icosahedral, T=4 particles that assemble from 240 copies of a single capsid protein precursor. This study is focused on the mechanisms underlying selection and packaging of genomic vRNAs by Helicoverpa armigera stunt virus. We demonstrate that the viral protein, p17, is packaged at low levels (between 4 and 8 copies per capsid) raising the possibility of icosahedral asymmetry in wild-type particles. p17 promotes packaging of vRNA2 by virus-like particles (VLPs) generated from plasmid-expressed vRNA2. The 5' and 3' UTRs of RNA2 are not required for encapsidation. VLPs produced by recombinant baculoviruses package vRNA2 at detectable levels even in the absence of p17 and apparently excluding baculoviral transcripts. This suggests a role for p17 in vRNA selectivity. This is one of few examples of the packaging of a minor non-structural protein by (+) ssRNA animal viruses.
α四病毒是小型正链单链RNA病毒，具有无包膜的二十面体T = 4颗粒，由240个单一衣壳蛋白前体拷贝组装而成。本研究聚焦于棉铃虫矮缩病毒选择和包装基因组病毒RNA的潜在机制。我们证明病毒蛋白p17以低水平包装（每个衣壳4至8个拷贝），这增加了野生型颗粒中二十面体不对称的可能性。p17通过由质粒表达的病毒RNA2产生的病毒样颗粒（VLP）促进病毒RNA2的包装。RNA2的5'和3'非翻译区对于衣壳化不是必需的。重组杆状病毒产生的VLP即使在没有p17的情况下也能以可检测的水平包装病毒RNA2，并且明显排除杆状病毒转录本。这表明p17在病毒RNA选择性中起作用。这是正链单链RNA动物病毒包装次要非结构蛋白的少数例子之一。
