Document 0410
 DOCN  M9490410
 TI    Differential growth kinetics are exhibited by human immunodeficiency
       virus type 1 TAR mutants.
 DT    9411
 AU    Harrich D; Hsu C; Race E; Gaynor RB; Department of Internal Medicine,
       University of Texas Southwestern; Medical Center, Dallas 75235-8594.
 SO    J Virol. 1994 Sep;68(9):5899-910. Unique Identifier : AIDSLINE
       MED/94335107
 AB    The human immunodeficiency virus type 1 (HIV-1) TAR element is critical
       for the activation of gene expression by the transactivator protein,
       Tat. Mutagenesis has demonstrated that a stable stem-loop RNA structure
       containing both loop and bulge structures transcribed from TAR is the
       major target for tat activation. Though transient assays have defined
       elements critical for TAR function, no studies have yet determined the
       role of TAR in viral replication because of the inability to generate
       viral stocks containing mutations in TAR. In the current study, we
       developed a strategy which enabled us to generate stable 293 cell lines
       which were capable of producing high titers of different viruses
       containing TAR mutations. Viruses generated from these cell lines were
       used to infect both T-lymphocyte cell lines and peripheral blood
       mononuclear cells. Viruses containing TAR mutations in either the upper
       stem, the bulge, or the loop exhibited dramatically decreased HIV-1 gene
       expression and replication in all cell lines tested. However, we were
       able to isolate lymphoid cell lines which stably expressed gene products
       from each of these TAR mutant viruses. Though the amounts of virus in
       these cell lines were roughly equivalent, cells containing TAR mutant
       viruses were extremely defective for gene expression compared with cell
       lines containing wild-type virus. The magnitude of this decrease in
       viral gene expression was much greater than previously seen in transient
       expression assays using HIV-1 long terminal repeat chloramphenicol
       acetyltransferase gene constructs. In contrast to the defects in viral
       growth found in T-lymphocyte cell lines, several of the viruses
       containing TAR mutations were much less defective for gene expression
       and replication in activated peripheral blood mononuclear cells. These
       results indicate that maintenance of the TAR element is critical for
       viral gene expression and replication in all cell lines tested, though
       the cell type which is infected is also a major determinant of the
       replication properties of TAR mutant viruses.
 DE    Base Sequence  Cell Line  *Gene Expression Regulation, Viral  Human  HIV
       Long Terminal Repeat/*GENETICS  HIV-1/*GROWTH & DEVELOPMENT  In Vitro
       Molecular Sequence Data  Nucleic Acid Conformation
       Oligodeoxyribonucleotides/CHEMISTRY  Structure-Activity Relationship
       Support, Non-U.S. Gov't  Support, U.S. Gov't, Non-P.H.S.  Support, U.S.
       Gov't, P.H.S.  T-Lymphocytes/MICROBIOLOGY  Transcription, Genetic
       *Virus Replication  JOURNAL ARTICLE

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