Document 0592
 DOCN  M9550592
 TI    Definition of a minimal activation domain in human T-cell leukemia virus
       type I Tax.
 DT    9505
 AU    Semmes OJ; Jeang KT; Molecular Virology Section, National Institute of
       Allergy and; Infectious Diseases, Bethesda, Maryland 20892.
 SO    J Virol. 1995 Mar;69(3):1827-33. Unique Identifier : AIDSLINE
       MED/95156615
 AB    Fourteen mutants were used to delineate a minimal activation domain in
       the Tax protein of human T-cell leukemia virus type I. In an assay using
       a Gal4-Tax (GalTx) fusion protein and a responsive promoter containing
       Gal4 consensus binding sites, we found that activation was squelched by
       coexpression of wild-type Tax protein in trans. When Tax mutants were
       tested for squelching, many competed effectively against GalTx. However,
       those containing changes in amino acids 289 to 322 failed to inhibit
       activity. In particular, three mutants that were expressed stably, with
       changes at amino acids 289, 296, and 320 respectively, did not squelch
       GalTx activity. On the other hand, mutants with individual changes at
       amino acid 3, 9, 29, 41, 273, and 337 efficiently inhibited GalTx
       function. Three other mutants failed to be stably expressed. In separate
       experiments, when fused alone to the DNA-binding domain of Gal4, amino
       acids 289 to 322 of Tax conferred trans activation ability. This fusion
       protein was able to activate a core promoter. These findings suggest
       that amino acids 289 to 322 define a region that contacts an essential
       transcription factor and that this region is a modular activation
       domain.
 DE    Amino Acid Sequence  Binding Sites  Chimeric Proteins  Consensus
       Sequence  Gene Expression Regulation, Viral  Gene Products,
       tax/*CHEMISTRY/METABOLISM  HTLV-I/*GENETICS  Molecular Sequence Data
       Sequence Deletion  Structure-Activity Relationship  Support, Non-U.S.
       Gov't  Support, U.S. Gov't, P.H.S.  *Trans-Activation (Genetics)
       Transcription Factors/METABOLISM  JOURNAL ARTICLE

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