title: Analysis of the 5-lipoxygenase promoter and characterization of a vitamin D receptor binding site.
abstract: 1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) and transforming growth factor beta (TGFbeta) potently induce 5-lipoxygenase (5-LO) in myeloid cells. We analyzed vitamin D receptor (VDR) binding to putative vitamin D response elements within the 5-LO promoter and analyzed its function by reporter gene analysis. Binding of VDR and retinoid X receptor to the promoter region was shown in DNase I footprinting, electrophoretic mobility shift and chromatin immunoprecipitation assays. However, the identified VDR binding region did not mediate induction of reporter gene activity by 1,25(OH)(2)D(3)/TGFbeta, neither in the 5-LO promoter context nor with the thymidine kinase (tk) promoter. Insertion of the rat atrial natriuretic factor VDRE in reporter plasmids containing the 5-LO promoter diminished induction by 1,25(OH)(2)D(3)/TGFbeta as compared with the tk promoter. Similarly, low inductions were obtained when cells were transiently or stably transfected with constructs containing various 5-LO promoter regions. Concerning basal promoter activity, we identified a positive regulatory region (-779 to -229), which includes the VDR binding region, in 5-LO-positive MonoMac6 cells. In summary, the VDR/RXR complex binds to putative VDREs in the 5-LO promoter, but other sequences outside the 5-LO promoter seem to be responsible or additionally required for the prominent induction of 5-LO mRNA expression by 1,25(OH)(2)D(3) and TGFbeta.
authors.affiliation: Institute of Pharmaceutical Chemistry/ZAFES, University of Frankfurt, Marie-Curie-Str. 9, D-60439 Frankfurt, Germany.
authors.forename: Bernd L
authors.initials: BL
authors.lastname: Sorg
authors.forename: Niko
authors.initials: N
authors.lastname: Klan
authors.forename: Sabine
authors.initials: S
authors.lastname: Seuter
authors.forename: David
authors.initials: D
authors.lastname: Dishart
authors.forename: Olof
authors.initials: O
authors.lastname: Rådmark
authors.forename: Andreas
authors.initials: A
authors.lastname: Habenicht
authors.forename: Carsten
authors.initials: C
authors.lastname: Carlberg
authors.forename: Oliver
authors.initials: O
authors.lastname: Werz
authors.forename: Dieter
authors.initials: D
authors.lastname: Steinhilber
mesh_terms: D001094:Arachidonate 5-Lipoxygenase / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites; D002117:Calcitriol / Q000378:metabolism / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D017930:Genes, Reporter; D018922:HL-60 Cells; D006801:Humans; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D018167:Receptors, Calcitriol / Q000378:metabolism*; D047488:Retinoid X Receptors / Q000378:metabolism; D017421:Sequence Analysis; D017384:Sequence Deletion; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D020298:U937 Cells
chemical_list: D018167:Receptors, Calcitriol; D047488:Retinoid X Receptors; D016212:Transforming Growth Factor beta; D001094:Arachidonate 5-Lipoxygenase; D002117:Calcitriol