       Document 0798
 DOCN  M9460798
 TI    The expression of the interleukin 6 gene is induced by the human
       immunodeficiency virus 1 TAT protein.
 DT    9404
 AU    Scala G; Ruocco MR; Ambrosino C; Mallardo M; Giordano V; Baldassarre F;
       Dragonetti E; Quinto I; Venuta S; Department of Biochemistry and
       Biomedical Technology, Medical; School, University Federico II, Naples,
       Italy.
 SO    J Exp Med. 1994 Mar 1;179(3):961-71. Unique Identifier : AIDSLINE
       MED/94157417
 AB    Human immunodeficiency virus 1 (HIV1) infection is associated with
       severe psoriasis, B cell lymphoma, and Kaposi's sarcoma. A deregulated
       production of interleukin 6 (IL-6) has been implicated in the
       pathogenesis of these diseases. The molecular mechanisms underlying the
       abnormal IL-6 secretion of HIV1-infected cells may include
       transactivation of the IL-6 gene by HIV1. To test this hypothesis, we
       used the pIL6Pr-chloramphenicol acetyltransferase (CAT) plasmid, an IL-6
       promoter-CAT construct, as a target of the transactivating function of
       the HIV1 TAT protein. By cotransfecting the pIL6Pr-CAT and the
       tat-expressing pSVT8 plasmid in MC3 B-lymphoblastoid or in HeLa
       epithelial cells, we observed that TAT transactivates the human IL-6
       promoter. These results were confirmed when pIL6Pr-CAT was transfected
       in MC3 or HeLa cells that constitutively expressed the tat gene in a
       sense (pSVT8 cells) or antisense (pSVT10 cells) orientation. 5' deletion
       plasmids of pIL6Pr-CAT, in which regions at -658, -287, and -172 were
       inserted 5' to the cat gene, were transiently transfected in pSVT10 and
       pSVT8 cells and showed that TAT-induced activation of the IL-6 promoter
       required a minimal region located between -287 and -54 bp. Moreover,
       experiments with plasmids carrying the 658, -287, and -172 bp regions of
       the IL-6 promoter inserted downstream to a TAR-deleted HIV1-LTR
       identified the sequence of 172 to -54 as the minimal region of the IL-6
       promoter required for TAT to transactivate the TAR-deleted HIV1-LTR. By
       DNA-protein binding experiments, tat-transfected cells expressed a
       consistent increase in kappa B and nuclear factor (NF)-IL-6 binding
       activity. Accordingly, the pDRCAT and IL-1REK9CAT, carrying tandem
       repeats of NF-kappa B or NF-IL6 binding motifs, respectively, were
       activated in TAT-expressing cells. The biological relevance of the
       TAT-induced IL-6 secretion was addressed by generating 7TD1 cells, an
       IL-6-dependent mouse cell line, stably expressing the tat gene. These
       tat-positive cells expressed the endogenous IL-6 gene, secreted high
       amounts of murine IL-6, and grew efficiently in the absence of exogenous
       IL-6. Moreover, the tat-positive 7TD1 cells sustained the growth of
       parental 7TD1 cells and showed a dramatic increase in their tumorigenic
       potency. These results suggest that TAT protein may play a role in the
       pathogenesis of some HIV1-associated diseases by modulating the
       expression of host cellular genes.
 DE    Animal  B-Lymphocytes  Base Sequence  Cell Line  Cell Line, Transformed
       Cell Transformation, Neoplastic  Chloramphenicol
       Acetyltransferase/BIOSYNTHESIS/METABOLISM  DNA Primers  Female  *Gene
       Expression  Gene Products, tat/BIOSYNTHESIS/*METABOLISM  Genes, tat
       Hela Cells  Human  HIV-1/*GENETICS/METABOLISM
       Interleukin-6/*BIOSYNTHESIS/GENETICS  Kinetics  Mice  Mice, Nude
       Molecular Sequence Data  Plasmids  Polymerase Chain Reaction  Promoter
       Regions (Genetics)  Support, Non-U.S. Gov't  Trans-Activation (Genetics)
       Transfection  JOURNAL ARTICLE

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

