Document 0051
 DOCN  M95B0051
 TI    Identification of the Tax interaction region of serum response factor
       that mediates the aberrant induction of immediate early genes through
       CArG boxes by HTLV-I Tax.
 DT    9511
 AU    Fujii M; Chuhjo T; Minamino T; Masaaki N; Miyamoto K; Seiki M;
       Department of Molecular Virology and Oncology, Kanazawa; University,
       Ishikawa, Japan.
 SO    Oncogene. 1995 Jul 6;11(1):7-14. Unique Identifier : AIDSLINE
       MED/95349938
 AB    Tax of human T-cell leukemia virus type I (HTLV-I) activates
       transcription at a CArG box of various immediate early genes such as the
       proto-oncogene c-fos. To do this, Tax does not directly bind to the CArG
       box, but instead binds to the CArG binding factor SRF. In this study, we
       investigated the domain of SRF required for the activation by Tax and
       studied the role of this domain on transcriptional regulation at the
       CArG box. Using a fusion protein of SRF with a yeast transcription
       factor GAL4, the 14 amino acid (aa) portion (aa 422-435) of SRF was
       identified as the domain required for Tax activation [Tax-responsive
       region of SRF (TRRS)]. By means of a two hybrid system, we showed that
       TRRS was essential for the interaction of SRF with Tax in vivo. The
       over-expression of SRF with a deletion of TRRS inhibited the Tax
       activation at the CArG box. Thus, TRRS is the domain of SRF that is
       essential for Tax activation at the CArG box. Unlike to Tax activation,
       TRRS was not required for TPA (12-o-tetradecanoylphobol-13-acetate)
       induction at the CArG box, but a TRRS deletion enhanced the basal
       activity at the CArG box both under serum-starved and TPA-stimulated
       conditions. These results suggest that TRRS negatively regulates the
       transcriptional activation function of SRF, and consequently contributes
       to the low basal activity at the CArG box before TPA induction.
 DE    Amino Acid Sequence  Base Sequence  DNA-Binding
       Proteins/*CHEMISTRY/PHYSIOLOGY  *Gene Expression Regulation  Gene
       Products, tax/*CHEMISTRY/PHYSIOLOGY  Genes, fos  *Genes, Immediate-Early
       Hela Cells  Human  Molecular Sequence Data  Nuclear
       Proteins/*CHEMISTRY/PHYSIOLOGY  Oligodeoxyribonucleotides  Support,
       Non-U.S. Gov't  Transcription Factors/CHEMISTRY/PHYSIOLOGY
       Transcription, Genetic  JOURNAL ARTICLE

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