Abstract
The HIV-1 accessory protein Nef enhances virus infectivity by facilitating an early post-entry step of infection. Nef acts in the virus producer cell, leading to a beneficial modification to HIV-1 particles. Nef itself is incorporated into HIV-1 particles, where it is cleaved by the viral protease during virion maturation. To probe the role of virion-associated Nef in HIV-1 infection, we generated a fusion protein consisting of the host protein cyclophilin A (CypA) linked to the amino terminus of Nef. The resulting CypA-Nef protein enhanced the infectivity of Nef-defective HIV-1 particles and was specifically incorporated into the virions via association with Gag during particle assembly. Pharmacologic or genetic inhibition of CypA-Nef binding to Gag prevented incorporation of CypA-Nef into virions and inhibited infectivity enhancement. Our results indicate that infectivity enhancement by Nef requires its association with a component of the assembling HIV-1 particle.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Amino Acid Substitution
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Base Sequence
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Binding Sites / genetics
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Cell Line
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Cyclophilin A / genetics
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Cyclophilin A / metabolism
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Cyclosporine / pharmacology
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DNA Primers / genetics
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Genes, nef
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HIV-1 / genetics
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HIV-1 / pathogenicity*
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HIV-1 / physiology*
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HeLa Cells
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Humans
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Multiprotein Complexes
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Mutation
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Plasmids / genetics
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Virulence / genetics
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Virulence / physiology
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Virus Assembly / physiology*
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gag Gene Products, Human Immunodeficiency Virus / physiology
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nef Gene Products, Human Immunodeficiency Virus / chemistry
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nef Gene Products, Human Immunodeficiency Virus / genetics
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nef Gene Products, Human Immunodeficiency Virus / physiology*
Substances
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DNA Primers
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Multiprotein Complexes
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Recombinant Fusion Proteins
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gag Gene Products, Human Immunodeficiency Virus
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nef Gene Products, Human Immunodeficiency Virus
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nef protein, Human immunodeficiency virus 1
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Cyclosporine
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Cyclophilin A