title: The West Nile virus assembly process evades the conserved antiviral mechanism of the interferon-induced MxA protein.
abstract: Flaviviruses have evolved means to evade host innate immune responses. Recent evidence suggests this is due to prevention of interferon production and signaling in flavivirus-infected cells. Here we show that the interferon-induced MxA protein can sequester the West Nile virus strain Kunjin virus (WNVKUN) capsid protein in cytoplasmic tubular structures in an expression-replication system. This sequestering resulted in reduced titers of secreted WNVKUN particles. We show by electron microscopy, tomography and 3D modeling that these cytoplasmic tubular structures form organized bundles. Additionally we show that recombinant ER-targeted MxA can restrict production of infectious WNVKUN under conditions of virus infection. Our results indicate a co-ordinated and compartmentalized WNVKUN assembly process may prevent recognition of viral components by MxA, particularly the capsid protein. This recognition can be exploited if MxA is targeted to intracellular sites of WNVKUN assembly. This results in further understanding of the mechanisms of flavivirus evasion from the immune system.
authors: School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia.
authors: Antje
authors: A
authors: Hoenen
authors: Leah
authors: L
authors: Gillespie
authors: Garry
authors: G
authors: Morgan
authors: Peter
authors: P
authors: van der Heide
authors: Alexander
authors: A
authors: Khromykh
authors: Jason
authors: J
authors: Mackenzie
mesh_terms: D000818:Animals; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D054884:Host-Pathogen Interactions; D006801:Humans; D057131:Immune Evasion; D064547:Myxovirus Resistance Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011485:Protein Binding; D019065:Virus Assembly; D017201:Virus Shedding; D014901:West Nile Fever / Q000235:genetics / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D014902:West Nile virus / Q000235:genetics / Q000276:immunology* / Q000502:physiology
chemical_list: D036022:Capsid Proteins; C579071:MX1 protein, human; D064547:Myxovirus Resistance Proteins
keywords: Innate immunity; Interferon-induced antiviral protein; MxA; Virus assembly; West Nile virus