title: Evolutionary conservation of an atypical glucocorticoid-responsive element in the human tyrosine hydroxylase gene.
abstract: The human tyrosine hydroxylase (hTH) gene has a 42 bp evolutionarily conserved region designated (CR) II at -7.24 kb, which bears 93% homology to the region we earlier identified as containing the glucocorticoid response element, a 7 bp activator protein-1 (AP-1)-like motif in the rat TH gene. We cloned this hTH-CRII region upstream of minimal basal hTH promoter in luciferase (Luc) reporter vector, and tested glucocorticoid responsiveness in human cell lines. Dexamethasone (Dex) stimulated Luc activity of hTH-CRII in HeLa cells, while mifepristone, a glucocorticoid receptor (GR) antagonist, prevented Dex stimulation. Deletion of the 7 bp 5'-TGACTAA at -7243 bp completely abolished the Dex-stimulated Luc activity of hTH-CRII construct. The AP-1 agonist, tetradeconoyl-12,13-phorbol acetate (TPA), also stimulated hTH promoter activity, and Dex and TPA together further accentuated this response. Chromatin immunoprecipitation assays revealed the presence of both GR and AP-1 proteins, especially Jun family members, at this hTH promoter site. Dex did not stimulate hTH promoter activity in a catecholaminergic cell line, which had low endogenous GR levels, but did activate the response when GR was expressed exogenously. Thus, our studies have clearly identified a glucocorticoid-responsive element in a 7 bp AP-1-like motif in the promoter region at -7.24 kb of the human TH gene.
authors: Department of Pharmacology and the Barshop Institute for Longevity and Aging Studies, University of Texas Health Sciences Center at San Antonio, San Antonio, Texas, USA. kadapakkam@uthscsa.edu
authors: C S
authors: CS
authors: Sheela Rani
authors: Alexandra
authors: A
authors: Soto-Pina
authors: Lorraine
authors: L
authors: Iacovitti
authors: Randy
authors: R
authors: Strong
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D003001:Cloning, Molecular; D017124:Conserved Sequence / Q000235:genetics*; D004247:DNA / Q000235:genetics; D003907:Dexamethasone / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D005822:Genetic Vectors; D005938:Glucocorticoids / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D008156:Luciferases / Q000235:genetics; D008969:Molecular Sequence Data; D016716:PC12 Cells; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011965:Receptors, Glucocorticoid / Q000235:genetics; D020218:Response Elements / Q000235:genetics*; D014162:Transfection; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics*
chemical_list: D005938:Glucocorticoids; D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; D015240:Phorbol 12,13-Dibutyrate; D003907:Dexamethasone; D004247:DNA; D008156:Luciferases; D014446:Tyrosine 3-Monooxygenase