title: Reverse genetic generation of recombinant Zaire Ebola viruses containing disrupted IRF-3 inhibitory domains results in attenuated virus growth in vitro and higher levels of IRF-3 activation without inhibiting viral transcription or replication.
abstract: The VP35 protein of Zaire Ebola virus is an essential component of the viral RNA polymerase complex and also functions to antagonize the cellular type I interferon (IFN) response by blocking activation of the transcription factor IRF-3. We previously mapped the IRF-3 inhibitory domain within the C terminus of VP35. In the present study, we show that mutations that disrupt the IRF-3 inhibitory function of VP35 do not disrupt viral transcription/replication, suggesting that the two functions of VP35 are separable. Second, using reverse genetics, we successfully recovered recombinant Ebola viruses containing mutations within the IRF-3 inhibitory domain. Importantly, we show that the recombinant viruses were attenuated for growth in cell culture and that they activated IRF-3 and IRF-3-inducible gene expression at levels higher than that for Ebola virus containing wild-type VP35. In the context of Ebola virus pathogenesis, VP35 may function to limit early IFN-beta production and other antiviral signals generated from cells at the primary site of infection, thereby slowing down the host's ability to curb virus replication and induce adaptive immunity.
authors.affiliation: Special Pathogens Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS G-14, Atlanta, GA 30329, USA.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Hartman
authors.forename: Jason E
authors.initials: JE
authors.lastname: Dover
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Towner
authors.forename: Stuart T
authors.initials: ST
authors.lastname: Nichol
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D002522:Chlorocebus aethiops; D046129:Ebola Vaccines / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D029043:Ebolavirus / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D019142:Hemorrhagic Fever, Ebola / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D006801:Humans; D050838:Interferon Regulatory Factor-3 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D016899:Interferon-beta / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D017434:Protein Structure, Tertiary / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics / Q000276:immunology; D014613:Vaccines, Attenuated / Q000235:genetics* / Q000276:immunology; D014709:Vero Cells; D014764:Viral Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D054334:Viral Regulatory and Accessory Proteins; D014779:Virus Replication / Q000187:drug effects / Q000235:genetics* / Q000276:immunology
chemical_list: D000998:Antiviral Agents; D046129:Ebola Vaccines; C494232:IRF3 protein, human; D050838:Interferon Regulatory Factor-3; C080980:VP35 protein, filovirus; D014613:Vaccines, Attenuated; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; D016899:Interferon-beta