Structure and assembly of the Ebola virus nucleocapsid

Nature. 2017 Nov 16;551(7680):394-397. doi: 10.1038/nature24490. Epub 2017 Nov 8.

Abstract

Ebola and Marburg viruses are filoviruses: filamentous, enveloped viruses that cause haemorrhagic fever. Filoviruses are within the order Mononegavirales, which also includes rabies virus, measles virus, and respiratory syncytial virus. Mononegaviruses have non-segmented, single-stranded negative-sense RNA genomes that are encapsidated by nucleoprotein and other viral proteins to form a helical nucleocapsid. The nucleocapsid acts as a scaffold for virus assembly and as a template for genome transcription and replication. Insights into nucleoprotein-nucleoprotein interactions have been derived from structural studies of oligomerized, RNA-encapsidating nucleoprotein, and cryo-electron microscopy of nucleocapsid or nucleocapsid-like structures. There have been no high-resolution reconstructions of complete mononegavirus nucleocapsids. Here we apply cryo-electron tomography and subtomogram averaging to determine the structure of Ebola virus nucleocapsid within intact viruses and recombinant nucleocapsid-like assemblies. These structures reveal the identity and arrangement of the nucleocapsid components, and suggest that the formation of an extended α-helix from the disordered carboxy-terminal region of nucleoprotein-core links nucleoprotein oligomerization, nucleocapsid condensation, RNA encapsidation, and accessory protein recruitment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chlorocebus aethiops
  • Cryoelectron Microscopy*
  • Ebolavirus / chemistry*
  • Ebolavirus / ultrastructure*
  • Electron Microscope Tomography*
  • HEK293 Cells
  • Humans
  • Marburgvirus / chemistry
  • Models, Molecular
  • Molecular Conformation
  • Nucleocapsid / chemistry*
  • Nucleocapsid / ultrastructure*
  • Nucleocapsid Proteins / chemistry
  • Nucleocapsid Proteins / ultrastructure*
  • RNA, Viral / chemistry
  • RNA, Viral / ultrastructure
  • Vero Cells

Substances

  • Nucleocapsid Proteins
  • RNA, Viral