Division of Swine Infectious Diseases, National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institutegrid.38587.31 of the Chinese Academy of Agricultural Sciences, Harbin, China.
J Virol. 2021 Oct 13;95(21):e0124621. doi: 10.1128/JVI.01246-21. Epub 2021 Aug 11.
Rotaviruses are the causative agents of severe and dehydrating gastroenteritis in children, piglets, and many other young animals. They replicate their genomes and assemble double-layered particles in cytoplasmic electron-dense inclusion bodies called "viroplasms." The formation of viroplasms is reportedly associated with the stability of microtubules. Although material transport is an important function of microtubules, whether and how microtubule-based transport influences the formation of viroplasms are still unclear. Here, we demonstrate that small viroplasms move and fuse in living cells. We show that microtubule-based dynein transport affects rotavirus infection, viroplasm formation, and the assembly of transient enveloped particles (TEPs) and triple-layered particles (TLPs). The dynein intermediate chain (DIC) is shown to localize in the viroplasm and to interact directly with nonstructural protein 2 (NSP2), indicating that the DIC is responsible for connecting the viroplasm to dynein. The WD40 repeat domain of the DIC regulates the interaction between the DIC and NSP2, and the knockdown of the DIC inhibited rotaviral infection, viroplasm formation, and the assembly of TEPs and TLPs. Our findings show that rotavirus viroplasms hijack dynein transport for fusion events, required for maximal assembly of infectious viral progeny. This study provides novel insights into the intracellular transport of viroplasms, which is involved in their biogenesis. Because the viroplasm is the viral factory for rotavirus replication, viroplasm formation undoubtedly determines the effective production of progeny rotavirus. Therefore, an understanding of the virus-host interactions involved in the biogenesis of the viroplasm is critical for the future development of prophylactic and therapeutic strategies. Previous studies have reported that the formation of viroplasms is associated with the stability of microtubules, whereas little is known about its specific mechanism. Here, we demonstrate that rotavirus viroplasm formation takes advantage of microtubule-based dynein transport mediated by an interaction between NSP2 and the DIC. These findings provide new insight into the intracellular transport of viroplasms.
轮状病毒是导致儿童、仔猪和许多其他幼小动物严重和脱水性胃肠炎的病原体。它们在细胞质电子致密包涵体中复制基因组并组装双层颗粒，称为“病毒包涵体”。据报道，病毒包涵体的形成与微管的稳定性有关。尽管物质运输是微管的重要功能，但微管是否以及如何影响病毒包涵体的形成尚不清楚。在这里，我们证明了活细胞中的小病毒包涵体能够移动和融合。我们表明，基于微管的动力蛋白运输会影响轮状病毒感染、病毒包涵体形成以及瞬时包膜颗粒（TEP）和三层颗粒（TLP）的组装。结果表明，动力蛋白中间链（DIC）定位于病毒包涵体中，并与非结构蛋白 2（NSP2）直接相互作用，表明 DIC 负责将病毒包涵体连接到动力蛋白。DIC 的 WD40 重复结构域调节 DIC 和 NSP2 之间的相互作用，DIC 的敲低抑制了轮状病毒感染、病毒包涵体形成以及 TEP 和 TLP 的组装。我们的研究结果表明，轮状病毒病毒包涵体劫持动力蛋白运输进行融合事件，这是组装感染性病毒子代所必需的。本研究为病毒包涵体的细胞内运输提供了新的见解，该运输涉及病毒包涵体的发生。由于病毒包涵体是轮状病毒复制的病毒工厂，因此病毒包涵体的形成无疑决定了有效产生子代轮状病毒。因此，了解涉及病毒包涵体发生的病毒-宿主相互作用对于未来预防性和治疗性策略的发展至关重要。以前的研究表明，病毒包涵体的形成与微管的稳定性有关，但其具体机制尚不清楚。在这里，我们证明轮状病毒病毒包涵体的形成利用了 NSP2 和 DIC 之间的相互作用介导的基于微管的动力蛋白运输。这些发现为病毒包涵体的细胞内运输提供了新的见解。
