title: Vif counteracts a cyclophilin A-imposed inhibition of simian immunodeficiency viruses in human cells.
abstract: Vif is a primate lentiviral accessory protein that is crucial for viral infectivity. Vif counteracts the antiviral activity of host deaminases such as APOBEC3G and APOBEC3F. We now report a novel function of African green monkey simian immunodeficiency virus (SIVagm) Vif that promotes replication of SIVagm in human cells lacking detectable deaminase activity. We found that cyclophilin A (CypA) was excluded from wild-type SIV particles but was efficiently packaged into vif-deficient SIVagm virions. The presence of CypA in vif-defective SIVagm was correlated with reduced viral replication. Infection of CypA knockout Jurkat cells or treatment of Jurkat cells with cyclosporine A eliminated the Vif-sensitive inhibition and resulted in replication profiles that were similar for wild-type and vif-deficient SIVagm. Importantly, the inhibitory effect of CypA was restricted to virus-producing cells and was TRIM5alpha independent. The abilities of SIVagm Vif to inhibit encapsidation of CypA and to increase viral infectivity were shared by rhesus macaque SIV Vif and thus seem to be general properties of SIV Vif proteins. Exclusion of CypA from SIVagm particles was not associated with intracellular degradation, suggesting a mode of Vif action distinct from that proposed for APOBEC3G. This is the first report of a novel vif-sensitive antiviral activity of human CypA that may limit zoonotic transmission of SIV and the first demonstration of CypA encapsidation into a virus other than human immunodeficiency virus type 1.
authors.affiliation: Laboratory of Molecular Microbiology, Viral Biochemistry Section, National Institute of Allergy and Infectious Diseases, NIH, Building 4, Room 310, 4 Center Drive, MSC 0460, Bethesda, Maryland 20892-0460, USA.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Alicia
authors.initials: A
authors.lastname: Buckler-White
authors.forename: Ritu
authors.initials: R
authors.lastname: Goila-Gaur
authors.forename: Eri
authors.initials: E
authors.lastname: Miyagi
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Khan
authors.forename: Sandrine
authors.initials: S
authors.lastname: Opi
authors.forename: Sandra
authors.initials: S
authors.lastname: Kao
authors.forename: Elena
authors.initials: E
authors.lastname: Sokolskaja
authors.forename: Thomas
authors.initials: T
authors.lastname: Pertel
authors.forename: Jeremy
authors.initials: J
authors.lastname: Luban
authors.forename: Klaus
authors.initials: K
authors.lastname: Strebel
mesh_terms: D000818:Animals; D000090103:Antiviral Restriction Factors; D002352:Carrier Proteins / Q000378:metabolism; D002460:Cell Line; D021984:Cyclophilin A / Q000235:genetics / Q000378:metabolism*; D016572:Cyclosporine / Q000378:metabolism; D016346:Gene Products, vif / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007166:Immunosuppressive Agents / Q000378:metabolism; D015302:Simian Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases; D014771:Virion / Q000378:metabolism; D014779:Virus Replication
chemical_list: D000090103:Antiviral Restriction Factors; D002352:Carrier Proteins; D016346:Gene Products, vif; D007166:Immunosuppressive Agents; D000070584:Tripartite Motif Proteins; D016572:Cyclosporine; C477346:TRIM5 protein, human; D044767:Ubiquitin-Protein Ligases; D021984:Cyclophilin A