Autographa californica multiple nucleopolyhedrovirus (AcMNPV) assembles its nucleocapsids and occlusion-derived virions (ODVs) in the nucleus, which requires AcMNPV regulation for viral structural proteins to accumulate in the nucleus during its replication in cells. It is generally accepted that the nuclear import receptor plays a predominant role in this process. CRM1 is a nuclear export receptor that forms an export complex with its cargo protein to exit the nucleus. We previously discovered that AcMNPV inhibited CRM1-dependent nuclear export by the viral protein Ac34. This finding suggested that Ac34 could sequester CRM1-dependent proteins in the nucleus and play a novel role in the nuclear accumulation of viral structural proteins. Using the CRM1 inhibitor leptomycin B (LMB), we demonstrated that CRM1 inhibition promoted AcMNPV replication, as LMB treatment readily increased the virus titer, and even functionally surrogate Ac34 to rescue the infectivity of an ac34-knockout virus. To elucidate whether CRM1 inhibition contributes to the nuclear accumulation of viral structural proteins, we systematically analyzed the impact of CRM1 inhibition on viral protein spatial distribution patterns. We found that the nucleocapsid protein Ac102 and ODV envelope protein E26 were retained in the nucleus in response to CRM1 inhibition by Ac34. This finding indicates that AcMNPV is evolving to simultaneously exploit bidirectional nucleocytoplasmic trafficking to assist in viral replication.

加州签名多核多角体病毒 (AcMNPV) 在细胞核中组装其核衣壳和封闭衍生病毒体 (ODV)，这需要 AcMNPV 调节病毒结构蛋白在细胞复制过程中在细胞核中积累。人们普遍认为，核输入受体在这一过程中起主要作用。CRM1 是一种核输出受体，它与其货物蛋白形成输出复合物以离开细胞核。我们之前发现 AcMNPV 通过病毒蛋白 Ac34 抑制 CRM1 依赖性核输出。这一发现表明，Ac34 可以在细胞核中隔离 CRM1 依赖性蛋白，并在病毒结构蛋白的核积累中发挥新的作用。使用 CRM1 抑制剂细霉素 B (LMB)，我们证明了 CRM1 抑制促进了 AcMNPV 复制，ac34-敲除病毒。为了阐明 CRM1 抑制是否有助于病毒结构蛋白的核积累，我们系统地分析了 CRM1 抑制对病毒蛋白空间分布模式的影响。我们发现核衣壳蛋白 Ac102 和 ODV 包膜蛋白 E26 保留在细胞核中，以响应 Ac34 对 CRM1 的抑制。这一发现表明，AcMNPV 正在进化为同时利用双向核质运输来协助病毒复制。