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Nature. 1995 Aug 17;376(6541):602-5.

Recognition of bZIP proteins by the human T-cell leukaemia virus transactivator Tax.

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  • 1Howard Hughes Medical Institute, University of Massachusetts Medical Center, Worcester 01605, USA.


Human T-cell leukaemia virus type I (HTLV-I) Tax protein increases the DNA binding of many cellular transcription factors that contain a basic region-leucine zipper (bZIP) DNA-binding domain. bZIP domains comprise a leucine-rich dimerization motif and a basic region that mediates DNA contact. How Tax recognizes diverse bZIPs is not understood. Here we show that no specific sequence of the leucine zipper is required for a Tax response. In contrast, the basic region is essential for the Tax-mediated DNA-binding increase, which can be eliminated by single substitutions of several conserved amino acids. Surprisingly, Tax alters the relative affinity of a bZIP for different DNA binding sites. Thus, through recognition of the conserved basic region. Tax increases DNA binding and modifies DNA site selection. Tax provides a model for how a single auxiliary factor can regulate multiple sequence-specific DNA-binding proteins.

[PubMed - indexed for MEDLINE]
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