Medical Research Council-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom.
Division of Virology, Department of Pathology, University of Cambridge, Cambridge United Kingdom.
J Virol. 2021 Jun 10;95(13):e0028221. doi: 10.1128/JVI.00282-21.
Vesivirus 2117 is an adventitious agent that has been responsible for lost productivity in biopharmaceutical production following contamination of Chinese hamster ovary cell cultures in commercial bioreactors. A member of the , 2117 is classified within the Vesivirus genus in a clade that includes canine and mink caliciviruses but is distinct from the vesicular exanthema of swine virus (VESV) clade, which includes the extensively studied feline calicivirus (FCV). We have used cryogenic electron microscopy (cryo-EM) to determine the structure of the capsid of this small, icosahedral, positive-sense-RNA-containing virus. We show that the outer face of the dimeric capsomeres, which contains the receptor binding site and major immunodominant epitopes in all caliciviruses studied thus far, is quite different from that of FCV. This is a consequence of a 22-amino-acid insertion in the sequence of the FCV major capsid protein that forms a "cantilevered arm" that both plays an important role in receptor engagement and undergoes structural rearrangements thought to be important for genome delivery to the cytosol. Our data highlight a potentially important difference in the attachment and entry pathways employed by the different clades of the genus. Vesivirus 2117 has caused significant losses in manufacturing of biopharmaceutical products following contamination of cell cultures used in their production. We report the structure of the vesivirus 2117 capsid, the shell that encloses the virus's genome. Comparison of this structure with that of a related vesivirus, feline calicivirus (FCV), highlighted potentially important differences related to virus attachment and entry. Our findings suggest that these two viruses may bind differently to receptors at the host cell surface. We also show that a region of the capsid protein of FCV that rearranges following receptor engagement is not present in vesivirus 2117. These structural changes in the FCV capsid have been shown to allow the assembly of a portal-like structure that is hypothesized to deliver the viral genome to the cell's interior. Our data suggest that the 2117 portal assembly may employ a different means of anchoring to the outer face of the capsid.
Vesivirus 2117 是一种偶然出现的病原体，它曾导致商业生物反应器中污染的中国仓鼠卵巢细胞培养物的生物制药生产失去生产力。2117 是 属的成员，在包括犬和貂科 Caliciviruses 的进化枝中被分类为 Vesivirus 属，但与包括广泛研究的猫 Calicivirus (FCV) 的 Vesicular Exanthema of Swine Virus (VESV) 进化枝不同。我们使用低温电子显微镜 (cryo-EM) 来确定这种小型、二十面体、含有正链 RNA 的病毒的衣壳结构。我们表明，二聚衣壳蛋白的外表面，其中包含迄今为止研究的所有 Caliciviruses 的受体结合位点和主要免疫显性表位，与 FCV 非常不同。这是由于 FCV 主要衣壳蛋白序列中的 22 个氨基酸插入形成了一个“悬臂臂”，该臂在受体结合中起着重要作用，并经历了结构重排，这些重排被认为对于将基因组递送到细胞质中很重要。我们的数据突出了不同 Caliciviruses 属进化枝所采用的附着和进入途径的潜在重要差异。Vesivirus 2117 曾在用于其生产的细胞培养物污染后导致生物制药产品制造的重大损失。我们报告了 Vesivirus 2117 衣壳的结构，即包围病毒基因组的外壳。将这种结构与相关的 Vesivirus，猫 Calicivirus (FCV) 进行比较，突出了与病毒附着和进入相关的潜在重要差异。我们的研究结果表明，这两种病毒可能以不同的方式与宿主细胞表面的受体结合。我们还表明，FCV 衣壳蛋白中在受体结合后重新排列的区域在 Vesivirus 2117 中不存在。FCV 衣壳中的这些结构变化已被证明允许组装一种类似门户的结构，该结构被假设用于将病毒基因组递送到细胞内部。我们的数据表明，2117 门户组装可能采用不同的方式与衣壳的外表面连接。
