       Document 0529
 DOCN  M9630529
 TI    The Vif protein of human and simian immunodeficiency viruses is packaged
       into virions and associates with viral core structures.
 DT    9603
 AU    Liu H; Wu X; Newman M; Shaw GM; Hahn BH; Kappes JC; Department of
       Medicine, University of Alabama at Birmingham; 35294, USA.
 SO    J Virol. 1995 Dec;69(12):7630-8. Unique Identifier : AIDSLINE
       MED/96079008
 AB    The vif gene of human and simian immunodeficiency viruses (HIV and SIV)
       encodes a late gene product that is essential for viral infectivity in
       natural target cells. Virions produced in the absence of Vif are
       abnormal in their ultrastructural morphology and are severely impaired
       in the ability to complete proviral DNA synthesis upon entry into new
       target cells. Because previous studies failed to detect Vif protein in
       virus particles, Vif is believed to influence virus infectivity
       indirectly, by affecting virion assembly, release, and/or maturation. In
       this report, we reexamined the possibility that Vif is a
       virion-associated protein. Utilizing high-titer Vif-specific antibodies,
       a sensitive immunoblot technique, and highly concentrated virus
       preparations, we detected a 23-kDa Vif-reactive protein in wild-type HIV
       type 1 (HIV-1) and a 27-kDa Vif-reactive protein in wild-type SIVSM
       virions. Neither protein was present in virions derived from
       vif-deficient HIV-1 and SIVSM proviral constructs. Vif protein content
       was similar among different strains of HIV-1 and was independent of the
       cell type (permissive or nonpermissive) used to produce the virus. To
       determine the subvirion localization of Vif, HIV-1 virions were treated
       with proteinase K or Triton X-100 to remove virion surface proteins and
       the viral membrane, respectively, purified through sucrose, and analyzed
       by immunoblot analysis. Vif protein content was not affected by the
       removal of external surface proteins or by the removal of the viral
       membrane and submembrane p17Gag matrix protein. Instead, Vif colocalized
       with viral core structures which sedimented at a density of 1.25 g/ml on
       linear sucrose gradients (enveloped HIV-1 particles sediment at a
       density of 1.17 g/ml). Finally, the amount of Vif protein packaged into
       virions was estimated to be on the order of 1 molecule of Vif for every
       20 to 30 molecules of p24Gag, or between 60 and 100 molecules of Vif per
       particle. These results indicate that Vif represents an integral
       component of HIV and SIV particles and raise the possibility that it
       plays a direct role in early replication events.
 DE    Amino Acid Sequence  Antibodies  Base Sequence  Comparative Study  DNA
       Primers  DNA Replication  DNA, Viral/BIOSYNTHESIS  Gene Deletion  Gene
       Products, vif/ANALYSIS/*BIOSYNTHESIS  *Genes, vif  Hela Cells  Human
       HIV/GENETICS/*METABOLISM  HIV-2/GENETICS/METABOLISM  Molecular Sequence
       Data  Mutagenesis  Peptide Fragments/CHEMISTRY/IMMUNOLOGY  Polymerase
       Chain Reaction  Proviruses/GENETICS/METABOLISM  Recombinant
       Proteins/ANALYSIS/BIOSYNTHESIS  Support, U.S. Gov't, Non-P.H.S.
       Support, U.S. Gov't, P.H.S.  SIV/GENETICS/*METABOLISM  Transfection
       Virion/GENETICS/*METABOLISM  JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

