Activator protein-1 is necessary for angiotensin-II stimulation of human adrenocorticotropin receptor gene transcription.
Previous studies have demonstrated that angiotensin-II (A-II) increases the human adrenocorticotropin receptor (hMC2R) gene expression in adrenal cells. In the present study, we have characterized two activator protein-1 (AP-1)-binding sites involved in the A-II stimulation of hMC2R gene transcription. Vectors containing different fragments of the hMC2R gene promoter inserted upstream of the luciferase gene, have been constructed. After transfection of H295R cells with these constructs and treatment of the cells by A-II during 48 h, maximal stimulation of the luciferase activity was obtained using the construct p(-263/+22)luc. Using progressively deleted constructs, three regions responsible for the A-II-stimulated transcription of hMC2R have been delineated. Inside these regions, two sequences displayed some homology with an AP-1 binding element (AP-108 and AP-203). Mutation of either AP-108 or AP-203 site induced a decrease of A-II-stimulated luciferase activity by 40% and 25%, respectively. Gel-shift analysis showed protein binding to these sites which was increased by an A-II treatment (maximum obtained after 3 h). Moreover, A-II could rapidly increase mRNA levels of several factors belonging to the Fos and Jun families which may be components of the AP-1 complex.
INSERM-INRA U418 and Université Claude Bernard Lyon 1, Hôpital Debrousse, Lyon, France. naville@lyon151.inserm.fr
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D000804:Angiotensin II / Q000502:physiology*; D001483:Base Sequence; D015152:Blotting, Northern; D004247:DNA; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018043:Receptors, Corticotropin / Q000235:genetics*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000502:physiology*; D014158:Transcription, Genetic / Q000502:physiology*; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D018043:Receptors, Corticotropin; D018808:Transcription Factor AP-1; D000804:Angiotensin II; D004247:DNA; D013755:Tetradecanoylphorbol Acetate