Interaction of the human T-cell lymphotrophic virus type I (HTLV-I) transcriptional activator Tax with cellular factors that bind specifically to the 21-base-pair repeats in the HTLV-I enhancer.
The human T-cell lymphotrophic virus type I (HTLV-I) Tax protein activates transcription from three 21-base-pair (bp) repeat sequences in the viral enhancer. Using gel electrophoretic mobility-shift assays, we now show that Tax interacts directly with the nuclear proteins, Tax activation factors (TAFs), that bind the 21-bp repeats. This interaction is demonstrated by decreased electrophoretic mobilities of the TAFs-21-bp-repeats complexes upon supply of Tax exogenously. Formation of the TAFs-21-bp-repeats and Tax-TAFs-21-bp-repeats complexes correlates with in vivo transactivation by Tax. Furthermore, interaction of Tax with TAFs enhances their binding to the 21-bp repeats. These data indicate that trans-activation by Tax is most likely mediated by interaction of Tax with TAFs.
Zhao
L J
LJ
Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106.
Giam
C Z
CZ
D001482:Base Composition; D001483:Base Sequence; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D004926:Escherichia coli / Q000235:genetics; D016356:Gene Products, tax / Q000235:genetics* / Q000378:metabolism*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D016356:Gene Products, tax; D009838:Oligodeoxyribonucleotides; D011993:Recombinant Fusion Proteins