Document 0354
 DOCN  M9650354
 TI    Coexpression of a nonsyncytium inducer HIV-1 glycoprotein inhibits
       syncytium formation by another HIV-1 Env protein.
 DT    9605
 AU    Li YY; O'Donnell MA; Perez LG; Molecular Biology and Biotechnology
       Program, Salem-Teikyo; University-Tampa Bay Research Institute, St.
       Petersburg, Florida; 33716, USA.
 SO    Virology. 1996 Jan 15;215(2):197-202. Unique Identifier : AIDSLINE
       MED/96146734
 AB    The biosynthesis and biological properties of the envelope glycoprotein
       from a primary isolate of the human immunodeficiency virus type 1, HIV-1
       YU2, and the Env product from the laboratory-adapted strain, HIV-1 LAI
       were compared in the absence of viral replication. We found that the
       level of expression and proteolytic processing into gp120/gp41 complexes
       of both glycoproteins was equivalent and independent of the cell type
       used. Although the two glycoproteins were detected on the surface of
       HeLa cells expressing high levels of CD4, only the HIV LAI Env product
       induced significant syncytium formation. Interestingly, when both
       glycoproteins were coexpressed in HeLa-CD4 cells, syncytium formation
       was greatly reduced. However, cell fusion could be restored by
       increasing amounts of the LAI envelope gene product. HeLa-CD4 cells
       expressing either glycoprotein fused with high efficiency to CEM-A
       cells, a hybrid of CEM and peripheral blood mononuclear cells,
       indicating that both glycoproteins were expressed in a biologically
       active form on the surface of these cells. These studies suggest that
       primary isolates and laboratory adapted stains may require, in addition
       to the CD4 receptor, independent accessory membrane components for the
       fusion activation step. Our results agree with the concept that virus
       entry requires the concerted activation of each glycoprotein subunit of
       the Env oligomeric complex.
 DE    Animal  Antigens, CD4/METABOLISM  Cell Line  Gene Expression Regulation,
       Viral  Giant Cells/VIROLOGY  Hela Cells  Human  HIV Envelope Protein
       gp120/GENETICS/*PHYSIOLOGY  HIV Envelope Protein
       gp41/GENETICS/*PHYSIOLOGY  HIV-1/*PHYSIOLOGY  Membrane Fusion  Membrane
       Glycoproteins/GENETICS/PHYSIOLOGY  Support, U.S. Gov't, P.H.S.  JOURNAL
       ARTICLE

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