Regulation of gene expression by HTLV-I Tax protein.
The human T-cell leukemia virus type I or HTLV-I is the causative agent of adult T-cell leukemia. A protein encoded by HTLV-I, Tax, activates viral gene expression and is essential for transforming T-lymphocytes. Tax activates HTLV-I gene expression via interactions with the ATF/CREB proteins and the coactivators CBP/p300 which assemble as a multiprotein complex on regulatory elements known as 21-bp repeats in the HTLV-I LTR. Tax can also activate expression from cellular genes including the interleukin-2 (IL-2) and the IL-2 receptor genes via increases in nuclear levels of NF-kappaB. Tax modulation of gene expression via the ATF/CREB and NF-kappaB pathways is linked to its transforming properties. This review discusses the mechanisms by which Tax regulates viral and cellular gene expression.
Bex
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Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, 75235-8594, USA.
Gaynor
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D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004742:Enhancer Elements, Genetic / Q000235:genetics; D015967:Gene Expression Regulation, Viral / Q000235:genetics*; D016356:Gene Products, tax / Q000502:physiology*; D015497:HIV-1 / Q000235:genetics*; D051548:Histone Acetyltransferases; D006801:Humans; D016328:NF-kappa B / Q000502:physiology; D056921:Nuclear Receptor Coactivator 3; D011401:Promoter Regions, Genetic / Q000235:genetics; D015534:Trans-Activators / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics*
D017362:Cyclic AMP Response Element-Binding Protein; D016356:Gene Products, tax; D016328:NF-kappa B; D015534:Trans-Activators; D014764:Viral Proteins; D051548:Histone Acetyltransferases; C538866:NCOA3 protein, human; D056921:Nuclear Receptor Coactivator 3