Many animal viruses replicate and are released from cells in close association to membranes. However, whether this is a passive process or is controlled by the virus remains poorly understood. Importantly, the genetic basis and evolvability of membrane-associated viral shedding have not been investigated. To address this, we performed a directed evolution experiment using coxsackievirus B3, a model enterovirus, in which we repeatedly selected the free-virion or the fast-sedimenting membrane-associated viral subpopulations. The virus responded to this selection regime by reproducibly fixing a series of mutations that altered the extent of membrane-associated viral shedding, as revealed by full-genome ultra-deep sequencing. Specifically, using site-directed mutagenesis, we showed that substitution N63H in the viral capsid protein VP3 reduced the ratio of membrane-associated to free viral particles by two orders of magnitude. These findings open new avenues for understanding the mechanisms and implications of membrane-associated viral transmission.

中文翻译：

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实验进化揭示了膜相关病毒释放的遗传基础。

许多动物病毒复制并从细胞中释放出来并与膜紧密结合。但是，这是一个被动过程还是由病毒控制仍然知之甚少。重要的是，尚未研究膜相关病毒脱落的遗传基础和可进化性。为了解决这个问题，我们使用柯萨奇病毒B3（一种肠道病毒模型）进行了定向进化实验，在该实验中，我们反复选择了游离病毒颗粒或快速沉降的膜相关病毒亚群。如全基因组超深度测序所揭示的那样，该病毒通过可复制地修复一系列改变膜相关病毒脱落程度的突变来对这种选择机制作出反应。具体来说，使用定点诱变，我们显示病毒衣壳蛋白VP3中的N63H取代将膜相关与游离病毒颗粒的比率降低了两个数量级。这些发现为了解膜相关病毒传播的机制和意义开辟了新途径。