Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity
Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity
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DOI：
10.3390/v11050403
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发表时间：
2019-05-01
期刊：
影响因子：
4.7
通讯作者：
Mounce, Bryan C.
中科院分区：
文献类型：
--
作者：
Dial, Courtney N.;Tate, Patrick M.;Mounce, Bryan C.
多胺是真核细胞中丰富的带正电荷的小分子，对RNA病毒复制至关重要。在真核细胞中，多胺促进诸如转录、翻译和DNA复制的过程，并且病毒类似地依赖于多胺来促进转录和翻译。多胺是否在病毒复制的其他阶段起作用仍然知之甚少。小核糖核酸病毒，包括柯萨奇病毒B3（CVB3），是敏感的多胺耗尽在体外和体内，然而，确切地说，多胺功能的小核糖核酸病毒感染还没有被描述。在这里，我们描述了CVB3突变体出现与多胺耗尽条件下通过。我们观察到2A和3C蛋白酶的突变，我们发现这些突变蛋白酶赋予多胺耗竭的抗性。使用分裂荧光素酶报告系统来测量蛋白酶活性，我们确定多胺促进病毒蛋白酶活性。我们进一步观察到2A和3C蛋白酶突变增强了多胺耗尽条件下的报告蛋白酶活性。最后，我们发现，这些突变促进裂解的细胞eIF4G在感染的多胺耗尽的细胞。总之，我们的研究结果表明，多胺是至关重要的蛋白酶的功能在小核糖核酸病毒感染。此外，这些数据突出了病毒蛋白酶作为潜在的抗病毒靶点，并突出了CVB3如何克服多胺消耗的抗病毒疗法。
Polyamines are small positively-charged molecules abundant in eukaryotic cells that are crucial to RNA virus replication. In eukaryotic cells, polyamines facilitate processes such as transcription, translation, and DNA replication, and viruses similarly rely on polyamines to facilitate transcription and translation. Whether polyamines function at additional stages in viral replication remains poorly understood. Picornaviruses, including Coxsackievirus B3 (CVB3), are sensitive to polyamine depletion both in vitro and in vivo; however, precisely how polyamine function in picornavirus infection has not been described. Here, we describe CVB3 mutants that arise with passage in polyamine-depleted conditions. We observe mutations in the 2A and 3C proteases, and we find that these mutant proteases confer resistance to polyamine depletion. Using a split luciferase reporter system to measure protease activity, we determined that polyamines facilitate viral protease activity. We further observe that the 2A and 3C protease mutations enhance reporter protease activity in polyamine-depleted conditions. Finally, we find that these mutations promote cleavage of cellular eIF4G during infection of polyamine-depleted cells. In sum, our results suggest that polyamines are crucial to protease function during picornavirus infection. Further, these data highlight viral proteases as potential antiviral targets and highlight how CVB3 may overcome polyamine-depleting antiviral therapies.