Document 0645
 DOCN  M9440645
 TI    Transcellular activation of the HTLV promoter by human hematopoietic
       cells.
 DT    9404
 AU    Baier-Bitterlich G; Rappaport J; Baier G; Looney D; Wong-Staal F; La
       Jolla Institute for Allergy and Immunology, California.
 SO    Oncogene. 1994 Jan;9(1):319-22. Unique Identifier : AIDSLINE
       MED/94134431
 AB    We examined the ability of hematopoietic cells to transactivate the HTLV
       promoter by a transcellular mechanism. HeLa cells containing a CAT
       reporter gene driven by the HTLV-2 promoter were cocultivated with
       hematopoietic cells of the B-(Raji), T-(HuT78, Jurkat) and
       monocyte/promyelocytic (THP-1, U937 and HL60) lineages. Cocultivation
       with U937 and HuT78 cells constitutively and significantly
       transactivated the HTLV-2 promoter, while no effect was observed with
       the other lines. However, activation of other T-cell lines (CEM, Jurkat,
       Molt-3 and MT-4) with a combination of phorbolester and
       phytohemagglutinin also resulted in potent transactivation. Supernatant
       from HuT78 cells exhibited detectable transactivating activity,
       suggesting that the activation is mediated by a secreted factor(s). This
       factor also transactivates the HTLV-1 promoter. We used a panel of
       HTLV-1 LTR deletion mutants to map the responsive elements to this
       factor(s). Unlike the response element to the HTLV transactivator
       protein, Tax, which can be mapped to a small region in the enhancer,
       maximal transactivation by the cellular factor(s) required the complete
       U3 sequence. Transcellular activation of the HTLV promoter by activated
       T-cells may play a role in the development of leukemia in HTLV infected
       individuals.
 DE    Hela Cells  Human  HTLV-BLV Viruses/*GENETICS  Lymphocyte Transformation
       *Promoter Regions (Genetics)  Support, Non-U.S. Gov't
       T-Lymphocytes/*PHYSIOLOGY  *Trans-Activation (Genetics)  JOURNAL ARTICLE

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