       Document 0528
 DOCN  M9630528
 TI    Augmentation of virus secretion by the human immunodeficiency virus type
       1 Vpu protein is cell type independent and occurs in cultured human
       primary macrophages and lymphocytes.
 DT    9603
 AU    Schubert U; Clouse KA; Strebel K; Laboratory of Molecular Microbiology,
       National Institute of; Allergy and Infectious Diseases, Bethesda,
       Maryland 20892-0460,; USA.
 SO    J Virol. 1995 Dec;69(12):7699-711. Unique Identifier : AIDSLINE
       MED/96079016
 AB    The human immunodeficiency virus type 1-specific Vpu protein is a small
       integral membrane phosphoprotein that induces degradation of the virus
       receptor CD4 in the endoplasmic reticulum and, independently, increases
       the release of progeny virions from infected cells. To address the
       importance of Vpu for virus replication in primary human cells such as
       peripheral blood mononuclear cells (PBMC) and monocyte-derived
       macrophages (MDM), we used three different sets of monocyte-tropic
       molecular clones of human immunodeficiency virus type 1: a primary
       isolate, AD8+, and two chimeric variants of the T-cell-tropic isolate
       NL4-3 carrying the env determinants of either AD8+ or SF162
       monocyte-tropic primary isolates. Isogenic variants of these chimeric
       viruses were constructed to express either wild-type Vpu or various
       mutants of Vpu. The effects of these mutations in the vpu gene on virus
       particle secretion from infected MDM or PBMC were assessed by
       determination of the release of virion-associated reverse transcriptase
       into culture supernatants, Western blot (immunoblot) analysis of
       pelleted virions, and steady-state or pulse-chase metabolic labeling.
       Wild-type Vpu increased virus release four- to sixfold in MDM and two-
       to threefold in PBMC, while nonphosphorylated Vpu and a C-terminal
       truncation mutant of Vpu were partially active on virus release in
       primary cells. These results demonstrate that Vpu regulates virus
       release in primary lymphocyte and macrophage cultures in a similar
       manner and to a similar extent to those previously observed in HeLa
       cells or CD4+ T-cell lines. Thus, our findings provide evidence that Vpu
       functions in a variety of human cells, both primary cells and continuous
       cell lines, and mutations in Vpu affect its biological activity
       independent of the cell type and virus isolate used.
 DE    Cells, Cultured  Cloning, Molecular  Comparative Study  Gene Expression
       Gene Products, vpu/BIOSYNTHESIS/ISOLATION & PURIF/*METABOLISM  Genome,
       Viral  Hela Cells  Human  HIV Seronegativity  HIV-1/GENETICS/*PHYSIOLOGY
       Kinetics  Lymphocytes/*VIROLOGY  Macrophages/*VIROLOGY
       Monocytes/VIROLOGY  Proviruses/GENETICS/PHYSIOLOGY  Support, Non-U.S.
       Gov't  Support, U.S. Gov't, P.H.S.  Time Factors  Transfection  *Virus
       Replication  JOURNAL ARTICLE

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

