Institute of Virology, Faculty of Medicine, Philipps University Marburg, 35037 Marburg, Germany.
Institute of Virology, Faculty of Medicine, Philipps University Marburg, 35037 Marburg, Germany;
Proc Natl Acad Sci U S A. 2018 Jan 30;115(5):1075-1080. doi: 10.1073/pnas.1712263115. Epub 2018 Jan 16.
The intracytoplasmic movement of nucleocapsids is a crucial step in the life cycle of enveloped viruses. Determination of the viral components necessary for viral nucleocapsid transport competency is complicated by the dynamic and complex nature of nucleocapsid assembly and the lack of appropriate model systems. Here, we established a live-cell imaging system based on the ectopic expression of fluorescent Ebola virus (EBOV) fusion proteins, allowing the visualization and analysis of the movement of EBOV nucleocapsid-like structures with different protein compositions. Only three of the five EBOV nucleocapsid proteins-nucleoprotein, VP35, and VP24-were necessary and sufficient to form transport-competent nucleocapsid-like structures. The transport of these structures was found to be dependent on actin polymerization and to have dynamics that were undistinguishable from those of nucleocapsids in EBOV-infected cells. The intracytoplasmic movement of nucleocapsid-like structures was completely independent of the viral matrix protein VP40 and the viral surface glycoprotein GP. However, VP40 greatly enhanced the efficiency of nucleocapsid recruitment into filopodia, the sites of EBOV budding.
核衣壳的胞质内运动是包膜病毒生命周期中的一个关键步骤。确定病毒核衣壳运输能力所必需的病毒成分很复杂，这是因为核衣壳的组装具有动态和复杂的性质，而且缺乏合适的模型系统。在这里，我们建立了一个基于荧光埃博拉病毒（EBOV）融合蛋白异位表达的活细胞成像系统，允许可视化和分析具有不同蛋白组成的 EBOV 核衣壳样结构的运动。只有 EBOV 核衣壳蛋白中的 5 种中的 3 种——核蛋白、VP35 和 VP24——是形成具有运输能力的核衣壳样结构所必需和充分的。这些结构的运输被发现依赖于肌动蛋白聚合，并且其动力学与感染 EBOV 的细胞中的核衣壳的动力学无法区分。核衣壳样结构的胞质内运动完全独立于病毒基质蛋白 VP40 和病毒表面糖蛋白 GP。然而，VP40 大大提高了核衣壳募集到丝状伪足（EBOV 出芽的部位）的效率。
