Short Communication Characterization of the Ebola virus nucleoprotein- RNA complex

When Ebola virus nucleoprotein (NP) is expressedin mammalian cells, it assembles into helicalstructures. Here, the recombinant NP helix purified from cells expressing NP was characterizedbiochemically and morphologically. We found that the recombinant NP helix is associated withnon-viral RNA, which is not protected from RNase digestion and that the morphology of thehelix changes depending on the environmental salt concentration. The N-terminal 450 aaresidues of NP are sufficient for these properties. However, digestion of the NP-associatedRNA eliminates the plasticity of the helix, suggesting that this RNA is an essential structuralcomponent of the helix, binding to individual NP molecules via the N-terminal 450 aa. Thesefindings enhance our knowledge of Ebola virus assembly and understanding of the Ebola viruslife cycle.