TAR independent activation of the human immunodeficiency virus in phorbol ester stimulated T lymphocytes

David Harrich, Joseph Garcia, Ronald Mitsuyasu, Richard Gaynor

Research output: Contribution to journalArticle

78 Citations (Scopus)

Abstract

Multiple regulatory elements in the human immunodeficiency virus long terminal repeat (HIV LTR) are required for activation of HIV gene expression. Previous transfection studies of HIV LTR constructs linked to the chloramphenicol acetyltransferase gene indicated that multiple regulatory regions including the enhancer, SP1, TATA and TAR regions were important for HIV gene expression. To characterize these regulatory elements further, mutations in these regions were inserted into both the 5′ and 3′ HIV LTRs and infectious proviral constructs were assembled. These constructs were translected into either HeLa cells, Jurkat cells or U937 cells in both the presence and absence of phorbol esters which have previously been demonstrated to activate HIV gene expression. Viral gene expression was assayed by the level of p24 gag protein released from cultures transfected with the proviral constructs. Results in all cell lines indicated that mutations of the SP1, TATA and the TAR loop and stem secondary structure resulted in marked decreases in gene expression while mutations of the enhancer motif or TAR primary sequence resulted in only slight decreases. However, viruses containing mutations in either the TAR loop sequences or stem secondary structure which were very defective for gene expression in untreated Jurkat cells, gave nearly wild-type levels of gene expression in phorbol ester-treated Jurkat cells but not in phorbol ester-treated HeLa or U937 cells. High level gene expression of these TAR mutant constructs in phorbol ester-treated Jurkat cells was eliminated by second site mutations in the enhancer region or by disruption of the tat gene. These results suggest that in stimulated T lymphocytes tat is likely capable of interacting with cellular factors which bind to both upstream and downstream regulatory elements resulting in activation of HIV gene expression.

Original languageEnglish (US)
Pages (from-to)4417-4423
Number of pages7
JournalEMBO Journal
Volume9
Issue number13
StatePublished - 1990

Fingerprint

T-cells
Phorbol Esters
Viruses
Gene expression
Chemical activation
HIV
T-Lymphocytes
Gene Expression
Jurkat Cells
Mutation
HIV Long Terminal Repeat
U937 Cells
HeLa Cells
tat Genes
Genes
Inverted Repeat Sequences
gag Gene Products
Chloramphenicol O-Acetyltransferase
Viral Genes
Nucleic Acid Regulatory Sequences

Keywords

  • Enhancer
  • Human immunodeficiency virus phorbol esters
  • Tat
  • Transcriptional regulation

ASJC Scopus subject areas

  • Genetics
  • Cell Biology

Cite this

TAR independent activation of the human immunodeficiency virus in phorbol ester stimulated T lymphocytes. / Harrich, David; Garcia, Joseph; Mitsuyasu, Ronald; Gaynor, Richard.

In: EMBO Journal, Vol. 9, No. 13, 1990, p. 4417-4423.

Research output: Contribution to journalArticle

Harrich, David ; Garcia, Joseph ; Mitsuyasu, Ronald ; Gaynor, Richard. / TAR independent activation of the human immunodeficiency virus in phorbol ester stimulated T lymphocytes. In: EMBO Journal. 1990 ; Vol. 9, No. 13. pp. 4417-4423.
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