title: Enhancers located in the vitamin D receptor gene mediate transcriptional autoregulation by 1,25-dihydroxyvitamin D3.
abstract: The regulatory actions of 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) on target genes are mediated by the vitamin D receptor (VDR). Interestingly, one of the genomic targets of 1,25(OH)(2)D(3) action is the VDR gene itself; however, the mechanism underlying this regulation is unknown. We investigated VDR autoregulation by screening the mouse VDR locus from 20kb upstream of the transcriptional start site (TSS) to 10kb downstream of the last exon using chromatin immunoprecipitation (ChIP)-DNA microarray analysis (ChIP/chip). Three potential VDR binding sites were located within introns lying downstream of the TSS and their activities confirmed through direct ChIP analysis. Further exploration revealed that one of these intronic regions was capable of conferring 1,25(OH)(2)D(3) response to both a downstream heterologous promoter and the minimal VDR promoter. Importantly, this regulatory region contained a classic vitamin D response element and was highly conserved within the human gene. We also demonstrated using ChIP analysis that the binding of VDR is associated with co-localization of RXR and the enhanced entry of RNA polymerase II. Thus, each of these sites appears likely to contribute to VDR autoregulation. Our studies using ChIP/chip analysis coupled to more traditional approaches define a direct mechanism whereby the VDR gene is upregulated by 1,25(OH)(2)D(3).
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706, USA. lazella@biochem.wisc.edu
authors.forename: Lee A
authors.initials: LA
authors.lastname: Zella
authors.forename: Sungtae
authors.initials: S
authors.lastname: Kim
authors.forename: Nirupama K
authors.initials: NK
authors.lastname: Shevde
authors.forename: J Wesley
authors.initials: JW
authors.lastname: Pike
mesh_terms: D000818:Animals; D002460:Cell Line; D004742:Enhancer Elements, Genetic; D006801:Humans; D051379:Mice; D012319:RNA Polymerase II / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000235:genetics* / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D018167:Receptors, Calcitriol; C118756:dihydroxy-vitamin D3; D014807:Vitamin D; D012319:RNA Polymerase II