共查询到20条相似文献,搜索用时 62 毫秒
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Chen F Ma L Dawson PA Sinal CJ Sehayek E Gonzalez FJ Breslow J Ananthanarayanan M Shneider BL 《The Journal of biological chemistry》2003,278(22):19909-19916
Intestinal reclamation of bile salts is mediated in large part by the apical sodium-dependent bile acid transporter (ASBT). The bile acid responsiveness of ASBT is controversial. Bile acid feeding in mice results in decreased expression of ASBT protein and mRNA. Mouse but not rat ASBT promoter activity was repressed in Caco-2, but not IEC-6, cells by chenodeoxycholic acid. A potential liver receptor homologue-1 (LRH-1) cis-acting element was identified in the bile acid-responsive region of the mouse but not rat promoter. The mouse, but not rat, promoter was activated by LRH-1, and this correlated with nuclear protein binding to the mouse but not rat LRH-1 element. The short heterodimer partner diminished the activity of the mouse promoter and could partially offset its activation by LRH-1. Interconversion of the potential LRH-1 cis-elements between the mouse and rat ASBT promoters was associated with an interconversion of LRH-1 and bile acid responsiveness. LRH-1 protein was found in Caco-2 cells and mouse ileum, but not IEC-6 cells or rat ileum. Bile acid response was mediated by the farnesoid X receptor, as shown by the fact that overexpression of a dominant-negative farnesoid X-receptor eliminated the bile acid mediated down-regulation of ASBT. In addition, ASBT expression in farnesoid X receptor null mice was unresponsive to bile acid feeding. In summary cell line- and species-specific negative feedback regulation of ASBT by bile acids is mediated by farnesoid X receptor via small heterodimer partner-dependent repression of LRH-1 activation of the ASBT promoter. 相似文献
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Analysis of the AP-1 sites in the IL-2 promoter. 总被引:18,自引:0,他引:18
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Transcriptional activation of the human papillomavirus-16 P97 promoter by an 88-nucleotide enhancer containing distinct cell-dependent and AP-1-responsive modules 总被引:17,自引:0,他引:17
T P Cripe A Alderborn R D Anderson S Parkkinen P Bergman T H Haugen U Pettersson L P Turek 《The New biologist》1990,2(5):450-463
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