title: Nef does not affect the efficiency of human immunodeficiency virus type 1 fusion with target cells.
abstract: The human immunodeficiency virus type 1 (HIV-1) accessory protein Nef stimulates viral infectivity by an unknown mechanism. Recent studies have suggested that Nef may act by regulating the efficiency of virus entry into cells. Here we provide evidence to the contrary. Using a quantitative assay of HIV-1 virus-cell fusion, we observed equivalent rates and extents of fusion of wild-type and Nef-defective HIV-1 particles with MT-4 cells and CD4-expressing HeLa cells. In studies using soluble CD4 (sCD4) to inhibit infection, wild-type and Nef-defective HIV-1 escaped the sCD4 block with similar kinetics. We conclude that Nef acts at a postentry step in infection, probably by facilitating intracellular transport of the HIV-1 ribonucleoprotein complex.
authors.affiliation: Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2363, USA.
authors.forename: Minoru
authors.initials: M
authors.lastname: Tobiume
authors.forename: Janet E
authors.initials: JE
authors.lastname: Lineberger
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Lundquist
authors.forename: Michael D
authors.initials: MD
authors.lastname: Miller
authors.forename: Christopher
authors.initials: C
authors.lastname: Aiken
mesh_terms: D015704:CD4 Antigens / Q000502:physiology; D015693:Gene Products, nef / Q000502:physiology*; D015497:HIV-1 / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008561:Membrane Fusion; D014771:Virion / Q000502:physiology; D054311:nef Gene Products, Human Immunodeficiency Virus
chemical_list: D015704:CD4 Antigens; D015693:Gene Products, nef; D054311:nef Gene Products, Human Immunodeficiency Virus