Mutations Abrogating VP35 Interaction with Double-Stranded RNA Render Ebola Virus Avirulent in Guinea Pigs

• DOI: 10.1128/jvi.02459-09
• Publication Date: 2010-01-14T02:59:47Z
• Authors: Kathleen C. Prins; Sebastien Delpeut; Daisy W. Leung; Olivier Reynard; Valentina A. Volc...; St. Patrick Reid; Parameshwaran Ram...; Washington B. Cá...; Gaya K. Amarasinghe; Viktor E. Volchkov; Christopher F. Ba...
• Keywords: VP40; Viral protein

ABSTRACT Ebola virus (EBOV) protein VP35 is a double-stranded RNA (dsRNA) binding inhibitor of host interferon (IFN)-α/β responses that also functions as viral polymerase cofactor. Recent structural studies identified key features, including central basic patch, required for dsRNA activity. To address the functional significance these features EBOV replication and pathogenesis, two point mutations, K319A/R322A, abrogate activity severely impair its suppression IFN-α/β production were identified. Solution nuclear magnetic resonance (NMR) spectroscopy X-ray crystallography reveal minimal perturbations in K319A/R322A double mutant suggest loss charge leads to altered function. Recombinant EBOVs encoding exhibit, relative wild-type viruses, growth attenuation IFN-defective Vero cells but severe impairment IFN-competent cells. In guinea pigs, revealed complete virulence. Strikingly, effectively immunized animals against subsequent challenge. These vivo studies, using recombinant combined with accompanying biochemical analyses directly correlate IFN inhibition pathogenesis. Moreover, provide framework development antivirals targeting this critical virulence factor.