State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, People's Republic of China.
University of Chinese Academy of Sciences, Beijing, People's Republic of China.
J Virol. 2020 Feb 28;94(6). doi: 10.1128/JVI.01674-19.
TER94 is a multifunctional AAA+ ATPase crucial for diverse cellular processes, especially protein quality control and chromatin dynamics in eukaryotic organisms. Many viruses, including coronavirus, herpesvirus, and retrovirus, coopt host cellular TER94 for optimal viral invasion and replication. Previous proteomics analysis identified the association of TER94 with the budded virions (BVs) of baculovirus, an enveloped insect large DNA virus. Here, the role of TER94 in the prototypic baculovirus multiple nucleopolyhedrovirus (AcMNPV) life cycle was investigated. In virus-infected cells, TER94 accumulated in virogenic stroma (VS) at the early stage of infection and subsequently partially rearranged in the ring zone region. In the virions, TER94 was associated with the nucleocapsids of both BV and occlusion-derived virus (ODV). Inhibition of TER94 ATPase activity significantly reduced viral DNA replication and BV production. Electron/immunoelectron microscopy revealed that inhibition of TER94 resulted in the trapping of nucleocapsids within cytoplasmic vacuoles at the nuclear periphery for BV formation and blockage of ODV envelopment at a premature stage within infected nuclei, which appeared highly consistent with its pivotal function in membrane biogenesis. Further analyses showed that TER94 was recruited to the VS or subnuclear structures through interaction with viral early proteins LEF3 and helicase, whereas inhibition of TER94 activity blocked the proper localization of replication-related viral proteins and morphogenesis of VS, providing an explanation for its role in viral DNA replication. Taken together, these data indicated the crucial functions of TER94 at multiple steps of the baculovirus life cycle, including genome replication, BV formation, and ODV morphogenesis. TER94 constitutes an important AAA+ ATPase that associates with diverse cellular processes, including protein quality control, membrane fusion of the Golgi apparatus and endoplasmic reticulum network, nuclear envelope reformation, and DNA replication. To date, little is known regarding the role(s) of TER94 in the baculovirus life cycle. In this study, TER94 was found to play a crucial role in multiple steps of baculovirus infection, including viral DNA replication and BV and ODV formation. Further evidence showed that the membrane fission/fusion function of TER94 is likely to be exploited by baculovirus for virion morphogenesis. Moreover, TER94 could interact with the viral early proteins LEF3 and helicase to transport and further recruit viral replication-related proteins to establish viral replication factories. This study highlights the critical roles of TER94 as an energy-supplying chaperon in the baculovirus life cycle and enriches our knowledge regarding the biological function of this important host factor.
TER94 是一种多功能的 AAA+ATP 酶，对多种细胞过程至关重要，尤其是真核生物中的蛋白质质量控制和染色质动力学。许多病毒，包括冠状病毒、疱疹病毒和逆转录病毒，都会利用宿主细胞的 TER94 来实现最佳的病毒入侵和复制。之前的蛋白质组学分析鉴定了 TER94 与杆状病毒（一种有包膜的昆虫大型 DNA 病毒）芽殖病毒（BV）的关联。在这里，研究了 TER94 在模式杆状病毒多角体病毒（AcMNPV）生命周期中的作用。在病毒感染的细胞中，TER94 在感染早期积累在病毒发生基质（VS）中，随后在环带区域部分重排。在病毒粒子中，TER94 与 BV 和封闭衍生病毒（ODV）的核衣壳都有关联。TER94 ATP 酶活性的抑制显著降低了病毒 DNA 复制和 BV 的产生。电子/免疫电子显微镜显示，TER94 的抑制导致核周细胞质空泡内的核衣壳捕获，从而形成 BV，并在感染核内的早期阶段阻断 ODV 的包膜，这与它在膜生物发生中的关键功能高度一致。进一步的分析表明，TER94 通过与病毒早期蛋白 LEF3 和解旋酶的相互作用被招募到 VS 或亚核结构中，而 TER94 活性的抑制阻止了与病毒 DNA 复制相关的病毒蛋白的正确定位和 VS 的形态发生，这为其在病毒 DNA 复制中的作用提供了一个解释。总之，这些数据表明 TER94 在杆状病毒生命周期的多个步骤中发挥着至关重要的作用，包括基因组复制、BV 形成和 ODV 形态发生。TER94 是一种重要的 AAA+ATP 酶，与多种细胞过程有关，包括蛋白质质量控制、高尔基体和内质网网络的膜融合、核膜重构和 DNA 复制。迄今为止，人们对 TER94 在杆状病毒生命周期中的作用知之甚少。在这项研究中，发现 TER94 在杆状病毒感染的多个步骤中发挥关键作用，包括病毒 DNA 复制以及 BV 和 ODV 的形成。进一步的证据表明，TER94 的膜分裂/融合功能可能被杆状病毒利用来进行病毒粒子形态发生。此外，TER94 可以与病毒早期蛋白 LEF3 和解旋酶相互作用，以运输并进一步招募与病毒复制相关的蛋白，从而建立病毒复制工厂。这项研究强调了 TER94 作为能量供应伴侣在杆状病毒生命周期中的关键作用，并丰富了我们对这一重要宿主因子的生物学功能的认识。
