Isolation and characterization of the tax protein of HTLV-I.
The transactivator protein tax of the human T-cell leukemia virus type I, HTLV-I, is responsible for transactivation of gene expression of viral and cellular genes and is involved in the onset of adult T-cell leukemia, ATL. Genetic deletion studies have implicated a region of the HTLV-I LTR designated as tax-acceptor region, TAR, which is the target of the tax protein. Using antibodies against a tax carboxyterminal synthetic decapeptide the tax protein was purified from an HTLV-I immortalized human T-lymphocyte cell line by immunoaffinity chromatography. The tax protein, purified to apparent homogeneity binds to double-stranded DNA irrespective of its origin from either a nuclear or cytoplasmic fraction of the HTLV-I immortalized cell-line - both of which harbor similar quantities of tax protein. The tax protein binds less to single-stranded DNA and not to single-stranded RNA in vitro. It also binds to DNA-cellulose and heparin-Sepharose. Nuclease treatment of isolated nuclei does not release the tax protein under conditions which release known DNA-binding proteins, such as the myb protein. Transactivation by the tax protein presumably involves host-cell factors, since it does not recognize specific DNA sequences.
Beimling
P
P
Max-Planck-Institute für Molekulare Genetik, Berlin, Federal Republic of Germany.
Moelling
K
K
D004247:DNA / Q000378:metabolism; D015486:HTLV-I Antigens / Q000302:isolation & purification* / Q000378:metabolism; D015368:Human T-lymphotropic virus 1 / Q000032:analysis*; D015534:Trans-Activators; D014157:Transcription Factors / Q000302:isolation & purification* / Q000378:metabolism
D015486:HTLV-I Antigens; D015534:Trans-Activators; D014157:Transcription Factors; D004247:DNA