title: An essential role of the CAAT/enhancer binding protein-alpha in the vitamin D-induced expression of the human steroid/bile acid-sulfotransferase (SULT2A1).
abstract: The vitamin D receptor (VDR) regulates steroid and drug metabolism by inducing the genes encoding phase I and phase II enzymes. SULT2A1 is a liver- and intestine-expressed sulfo-conjugating enzyme that converts the alcohol-OH of neutral steroids, bile acids, and drugs to water-soluble sulfated metabolites. 1alpha,25-Dihydroxyvitamin D3 [1,25-(OH)2D3] induces SULT2A1 gene transcription after the recruitment of VDR to the vitamin D-responsive chromatin region of SULT2A1. A composite element in human SULT2A1 directs the 1,25-(OH)2D3-mediated induction of natural and heterologous promoters. This element combines a VDR/retinoid X receptor-alpha-binding site [vitamin D response element (VDRE)], which is an imperfect inverted repeat 2 of AGCTCA, and a CAAT/enhancer binding protein (C/EBP)-binding site located 9 bp downstream to VDRE. The binding sites were identified by EMSA, antibody supershift, and deoxyribonuclease I footprinting. C/EBP-alpha at the composite element plays an essential role in the VDR regulation of SULT2A1, because 1) induction was lost for promoters with inactivating mutations at the VDRE or C/EBP element; 2) SULT2A1 induction by 1,25-(OH)2D3 in C/EBP-alpha-deficient cells required the expression of cotransfected C/EBP-alpha; and 3) C/EBP-beta did not substitute for C/EBP-alpha in this regulation. VDR and C/EBP-alpha were recruited concurrently to the composite element along with the coactivators p300, steroid receptor coactivator 1 (SRC-1), and SRC-2, but not SRC-3. VDR and C/EBP-alpha associated endogenously as a DNA-dependent, coimmunoprecipitable complex, which was detected at a markedly higher level in 1,25-(OH)2D3-treated cells. These results provide the first example of the essential role of the interaction in cis between C/EBP-alpha and VDR in directing 1,25-(OH)2D3-induced expression of a VDR target gene.
authors.affiliation: Department of Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center, San Antonio, Texas 78245, USA.
authors.forename: Chung S
authors.initials: CS
authors.lastname: Song
authors.forename: Ibtissam
authors.initials: I
authors.lastname: Echchgadda
authors.forename: Young-Kyo
authors.initials: YK
authors.lastname: Seo
authors.forename: Taesung
authors.initials: T
authors.lastname: Oh
authors.forename: Soyoung
authors.initials: S
authors.lastname: Kim
authors.forename: Sung-A
authors.initials: SA
authors.lastname: Kim
authors.forename: Sunghwan
authors.initials: S
authors.lastname: Cho
authors.forename: Liheng
authors.initials: L
authors.lastname: Shi
authors.forename: Bandana
authors.initials: B
authors.lastname: Chatterjee
mesh_terms: D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism*; D002117:Calcitriol / Q000494:pharmacology*; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000378:metabolism; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D000072482:Retinoic Acid Receptor alpha; D015238:Sulfotransferases / Q000235:genetics*; D014162:Transfection; D030181:Vitamin D Response Element
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; C000607071:RARA protein, human; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D018168:Receptors, Retinoic Acid; D011994:Recombinant Proteins; D000072482:Retinoic Acid Receptor alpha; D004247:DNA; D015238:Sulfotransferases; C028152:alcohol sulfotransferase; D002117:Calcitriol