Center for Vaccine Innovation, La Jolla Institute for Immunology, La Jolla, CA 92037, USA.
Electron Microscopy Core, University of California, San Diego, La Jolla, CA 92037, USA.
Cell. 2024 Oct 3;187(20):5587-5603.e19. doi: 10.1016/j.cell.2024.08.044. Epub 2024 Sep 17.
Filoviruses, including the Ebola and Marburg viruses, cause hemorrhagic fevers with up to 90% lethality. The viral nucleocapsid is assembled by polymerization of the nucleoprotein (NP) along the viral genome, together with the viral proteins VP24 and VP35. We employed cryo-electron tomography of cells transfected with viral proteins and infected with model Ebola virus to illuminate assembly intermediates, as well as a 9 Å map of the complete intracellular assembly. This structure reveals a previously unresolved third and outer layer of NP complexed with VP35. The intrinsically disordered region, together with the C-terminal domain of this outer layer of NP, provides the constant width between intracellular nucleocapsid bundles and likely functions as a flexible tether to the viral matrix protein in the virion. A comparison of intracellular nucleocapsids with prior in-virion nucleocapsid structures reveals that the nucleocapsid further condenses vertically in the virion. The interfaces responsible for nucleocapsid assembly are highly conserved and offer targets for broadly effective antivirals.
丝状病毒，包括埃博拉病毒和马尔堡病毒，会引起出血热，致死率高达 90%。病毒核衣壳是由核蛋白（NP）沿着病毒基因组聚合，与病毒蛋白 VP24 和 VP35 一起形成的。我们通过转染病毒蛋白并感染模型埃博拉病毒的细胞的冷冻电子断层扫描来阐明组装中间体，以及完整的细胞内组装的 9Å 图谱。该结构揭示了一个以前未解决的 NP 与 VP35 复合的第三层和外层。这个外层 NP 的无规卷曲区域及其 C 末端结构域提供了细胞内核衣壳束之间的恒定宽度，并可能作为病毒基质蛋白在病毒中的灵活系绳发挥作用。与之前病毒核衣壳结构的细胞内核衣壳比较表明，核衣壳在病毒中进一步垂直浓缩。负责核衣壳组装的界面高度保守，为广泛有效的抗病毒药物提供了目标。
