Limits of structural plasticity in a picornavirus capsid revealed by a massively expanded equine rhinitis A virus particle.
Limits of structural plasticity in a picornavirus capsid revealed by a massively expanded equine rhinitis A virus particle.
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DOI：
10.1128/jvi.01979-13
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发表时间：
2014-06
影响因子：
5.4
通讯作者：
Ranson NA
中科院分区：
文献类型：
--
作者：
Bakker SE;Groppelli E;Pearson AR;Stockley PG;Rowlands DJ;Ranson NA
小核糖核酸病毒科是一种小的、无包膜的病毒，包括人类和动物的主要病原体。它们具有正意义的单链RNA基因组，而这些基因组被引入细胞以引发感染的机制尚不清楚。与成熟病毒粒子相比，几种小核糖核酸病毒假定的未包被中间粒子的结构显示出有限的膨胀和一些增加的孔隙度。在这里，我们展示了天然马鼻炎A病毒（ERAV）的低温电镜结构，以及大规模扩展的ERAV颗粒的结构，每个分辨率为~ 17 -Å。扩展后的结构在颗粒3倍轴上具有较大的孔隙，并且丢失了RNA基因组和衣壳蛋白VP4。因此，扩大的结构既说明了衣壳结构可塑性的局限性，也说明了基因组RNA可能退出的合理途径。小核糖核酸病毒是重要的动物和人类病原体，在保护蛋白衣壳内保护其基因组rna。在感染后，这种基因组RNA必须能够离开衣壳来启动新一轮的感染。我们在这里描述了一种独特的，大规模扩展状态的马鼻炎a病毒的结构，为这种退出可能发生的方式提供了见解。
The Picornaviridae family of small, nonenveloped viruses includes major pathogens of humans and animals. They have positive-sense, single-stranded RNA genomes, and the mechanism(s) by which these genomes are introduced into cells to initiate infection remains poorly understood. The structures of presumed uncoating intermediate particles of several picornaviruses show limited expansion and some increased porosity compared to the mature virions. Here, we present the cryo-electron microscopy structure of native equine rhinitis A virus (ERAV), together with the structure of a massively expanded ERAV particle, each at ∼17–Å resolution. The expanded structure has large pores on the particle 3-fold axes and has lost the RNA genome and the capsid protein VP4. The expanded structure thus illustrates both the limits of structural plasticity in such capsids and a plausible route by which genomic RNA might exit. IMPORTANCE Picornaviruses are important animal and human pathogens that protect their genomic RNAs within a protective protein capsid. Upon infection, this genomic RNA must be able to leave the capsid to initiate a new round of infection. We describe here the structure of a unique, massively expanded state of equine rhinitis A virus that provides insight into how this exit might occur.