title: NF-kappaB inhibits transcription of the H(+)-K(+)-ATPase alpha(2)-subunit gene: role of histone deacetylases.
abstract: The H(+)-K(+)-ATPase alpha(2) (HKalpha(2)) gene plays a central role in potassium homeostasis, yet little is known about its transcriptional control. We recently demonstrated that the proximal promoter confers basal transcriptional activity in mouse inner medullary collecting duct 3 cells. We sought to determine whether the kappaB DNA binding element at -104 to -94 influences basal HKalpha(2) gene transcription in these cells. Recombinant NF-kappaB p50 footprinted the region -116/-94 in vitro. Gel shift and supershift analysis revealed NF-kappaB p50- and p65-containing DNA-protein complexes in nuclear extracts of mouse inner medullary collecting duct 3 cells. A promoter-luciferase construct with a mutated -104/-94 NF-kappaB element exhibited higher activity than the wild-type promoter in transfection assays. Overexpression of NF-kappaB p50, p65, or their combination trans-repressed the HKalpha(2) promoter. The histone deacetylase (HDAC) inhibitor trichostatin A partially reversed NF-kappaB-mediated trans-repression of the HKalpha(2) promoter. HDAC6 overexpression inhibited HKalpha(2) promoter activity, and HDAC6 coimmunoprecipitated with NF-kappaB p50 and p65. These results suggest that HDAC6, recruited to the DNA protein complex, acts with NF-kappaB to suppress HKalpha(2) transcription and identify NF-kappaB p50 and p65 as novel binding partners for HDAC6.
authors.affiliation: Departments of Internal Medicine and of Integrative Biology, Pharmacology, and Physiology, The University of Texas Medical School at Houston, Houston, Texas 77030, USA.
authors.forename: Wenzheng
authors.initials: W
authors.lastname: Zhang
authors.forename: Bruce C
authors.initials: BC
authors.lastname: Kone
mesh_terms: D000818:Animals; D002461:Cell Line, Transformed; D003106:Colon / Q000201:enzymology; D018983:DNA Footprinting; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000502:physiology; D017506:H(+)-K(+)-Exchanging ATPase / Q000235:genetics* / Q000378:metabolism*; D000073864:Histone Deacetylase 6; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000378:metabolism*; D006877:Hydroxamic Acids / Q000494:pharmacology; D066298:In Vitro Techniques; D007685:Kidney Tubules, Collecting / Q000166:cytology / Q000201:enzymology*; D051379:Mice; D016328:NF-kappa B / Q000235:genetics* / Q000378:metabolism; D052002:NF-kappa B p50 Subunit; D011401:Promoter Regions, Genetic / Q000502:physiology; D051996:Transcription Factor RelA; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D051996:Transcription Factor RelA; C012589:trichostatin A; C433811:HDAC6 protein, human; C499033:Hdac6 protein, mouse; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases; D017506:H(+)-K(+)-Exchanging ATPase