       Document 0045
 DOCN  M9630045
 TI    Interaction of bovine leukemia virus transactivator Tax with bZip
       proteins.
 DT    9603
 AU    Boros IM; Tie F; Giam CZ; Department of Medicine, Case Western Reserve
       University,; Cleveland, Ohio 44106, USA.
 SO    Virology. 1995 Dec 1;214(1):207-14. Unique Identifier : AIDSLINE
       MED/96095239
 AB    The bovine leukemia virus transactivator, BLV Tax, augments
       transcription from three imperfect 21-bp repeats in the viral
       transcriptional regulatory region. Each BLV 21-bp repeat contains a cAMP
       response element (CRE) in the center and unique 5' and 3' neighboring
       sequences which are crucial for the transcriptional activation by BLV
       Tax. Here we describe the interactions of recombinant BLV Tax with
       cellular bZip proteins. The recombinant BLV Tax, tagged at the carboxy
       terminus with a hexahistidine extension, was prepared by solubilization
       in 6 M guanidine hydrochloride and renaturation on the Ni(2+)-chelating
       Sepharose gel matrix. The renatured BLV TaxH6 activates the BLV LTR when
       introduced into HeLa cells by scrape loading. Furthermore, the purified
       BLV TaxH6 enhances binding of members of the CREB/ATF family of bZip
       proteins to CRE motifs by interacting with their bZip domains in vitro.
       Chemical cross-linking indicates that dimerization of bZip proteins such
       as CREB becomes greatly facilitated in the presence of BLV Tax. These
       results suggest that BLV Tax interacts directly with CREB/ATF-like
       factors to activate viral mRNA transcription.
 DE    Amino Acid Sequence  Animal  Base Sequence  Cattle  DNA Primers
       DNA-Binding Protein, Cyclic AMP-Responsive/METABOLISM  DNA-Binding
       Proteins/*METABOLISM  DNA, Viral/METABOLISM  Gene Products,
       tax/*METABOLISM  Human  Leukemia Virus, Bovine/GENETICS/*METABOLISM
       Molecular Sequence Data  Protein Binding  Repetitive Sequences, Nucleic
       Acid  Retroviridae Proteins, Oncogenic/*METABOLISM  Support, Non-U.S.
       Gov't  Support, U.S. Gov't, P.H.S.  Trans-Activators/*METABOLISM
       JOURNAL ARTICLE

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

