title: A cooperative interaction of human T-cell leukemia virus type 1 Tax with the p21 cyclin-dependent kinase inhibitor activates the human immunodeficiency virus type 1 enhancer.
abstract: Interactions between the Tax transactivator of human T-cell leukemia virus type 1 (HTLV-1) and a cell cycle regulatory protein have been examined. We report cooperative stimulation of human immunodeficiency virus type 1 gene expression by Tax and a regulator of cell cycle progression, the p21 cyclin-dependent kinase inhibitor (CKI). This cooperativity results from the effect of p21 on transcriptional coactivation by Tax-induced NF-kappaB. This effect was abrogated by a mutation in Tax which specifically eliminated NF-kappaB induction, was inhibitable by IkappaB-alpha, and was markedly reduced in human immunodeficiency virus reporter plasmids with mutant kappaB sites. These studies demonstrate that transcriptional activation by Tax is influenced by cell cycle regulatory proteins.
authors.affiliation: Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0650, USA.
authors.forename: S F
authors.initials: SF
authors.lastname: Parker
authors.forename: N D
authors.initials: ND
authors.lastname: Perkins
authors.forename: S D
authors.initials: SD
authors.lastname: Gitlin
authors.forename: G J
authors.initials: GJ
authors.lastname: Nabel
mesh_terms: D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics*; D004742:Enhancer Elements, Genetic / Q000235:genetics*; D016355:Genes, pX; D015497:HIV-1 / Q000235:genetics*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D006801:Humans; D016328:NF-kappa B / Q000235:genetics; D015533:Transcriptional Activation
chemical_list: C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D016328:NF-kappa B