Activation of the human vimentin gene by the Tax human T-cell leukemia virus. I. Mechanisms of regulation by the NF-kappa B transcription factor.
The molecular basis for transactivation of the human vimentin gene by the Tax protein from the human T-cell leukemia virus (HTLV-1) is analyzed in this report. We first demonstrate that the factor NF-kappa B binds to the vimentin promoter. Using gel retardation assays, we found the putative NF-kappa B protein. Specific antibodies and competition experiments between the NF-kappa B-binding site in the interleukin-2R alpha and HIV-1 promoters and the vimentin promoter show that the three sites have identical affinity for the factor. We further show that the mechanisms of activation of NF-kappa B by the Tax protein involve a cellular inducer. Nuclear extract from lymphoid cells expressing Tax can induce in vitro a NF-kappa B binding activity in nonlymphoid cytosolic extract. This inducer, if preexisting in an inactivate state in T-cells which are not expressing Tax, cannot be switched to an active state by addition of partially purified Tax protein. While found in the nucleus of Tax-expressing cells in our experiments, this inducer might be cytoplasmic as well. In a first attempt to identify and characterize the inducer, we present the results of fractionation assays of nuclear extract.
Lilienbaum
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Laboratoire de Biologie Moléculaire de la Differentiation de l'Université Paris 7, France.
Paulin
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D
D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D002467:Cell Nucleus / Q000378:metabolism; D016384:Consensus Sequence; D003600:Cytosol / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D003840:Deoxycholic Acid / Q000494:pharmacology; D005786:Gene Expression Regulation; D016356:Gene Products, tax / Q000494:pharmacology*; D006367:HeLa Cells; D015368:Human T-lymphotropic virus 1 / Q000737:chemistry*; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D014746:Vimentin / Q000235:genetics*
D016356:Gene Products, tax; D016328:NF-kappa B; D014746:Vimentin; D003840:Deoxycholic Acid; D004247:DNA