20β-hydroxysteroid dehydrogenase gene promoter: Potential role for cyclic AMP and xenobiotic responsive elements
20β-hydroxysteroid dehydrogenase gene promoter: Potential role for cyclic AMP and xenobiotic responsive elements
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DOI：
10.1016/j.gene.2012.07.017
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发表时间：
2012-11-01
期刊：
影响因子：
3.5
通讯作者：
Nagahama, Y.
中科院分区：
文献类型：
--
作者：
Sreenivasulu, G.;Senthilkumaran, B.;Nagahama, Y.
硬骨鱼20 β-羟基类固醇脱氢酶（20 β-HSD）参与最终卵母细胞成熟和类固醇激素代谢。它在结构和功能上与哺乳动物羰基还原酶相似，后者参与内源性羰基和异生物质化合物的代谢。为了研究20 β-HSD的转录调控机制，我们克隆了虹鳟和鲶鱼20 β-HSD的启动子。启动子基序的分析，在计算机上确定了转录因子结合的几个位点的存在，包括cAMP，异生素和类固醇激素响应元件。用进行性缺失构建体进行的荧光素酶报告基因测定表明，鳟鱼的20 β-HSD B型不具有启动子活性，而鳟鱼的20 β-HSD A型和鲶鱼的20 β-HSD启动子显示基础启动子活性。侧接CAAT盒的TATA盒对于基础转录是重要的。启动子中cAMP反应元件的缺失显著降低了基础启动子活性。报告基因测定法与毛喉素和IBMX，药物增加细胞内cAMP诱导的启动子活性超过基础水平。有趣的是，β-萘噻酮，一种芳香烃受体配体，诱导20 β-HSD启动子活性，并通过在体内诱导鲶鱼肝脏中20 β-HSD表达进一步证明。这些结果首次证明20 β-HSD表达不仅受cAMP调节，而且受外源性物质调节，进一步的研究可能对该酶的普遍分布和广泛的底物特异性提供重要意义。(C)2012爱思唯尔有限公司版权所有。
Teleostean 20 beta-hydroxysteroid dehydrogenase (20 beta-HSD) is involved in final oocyte maturation and steroid hormone metabolism. It has structural and functional similarities to mammalian carbonyl reductases that are involved in the metabolism of endogenous carbonyl and xenobiotic compounds. To understand the transcriptional regulation of 20 beta-HSD, here we report the cloning of 20 beta-HSD promoter from two fish species, rainbow trout and air-breathing catfish. Analysis of the promoter motifs, in silico identified the presence of several sites for transcription factor binding including cAMP, xenobiotic and steroid hormone responsive elements. Luciferase reporter assays with progressive deletion constructs demonstrated that 20 beta-HSD type B of trout has no promoter activity while 20 beta-HSD type A of trout and catfish 20 beta-HSD promoters showed basal promoter activity. A TATA box flanked by a CAAT box is important for basal transcription. Deletion of cAMP responsive element in the promoter decreased basal promoter activity significantly. Reporter assays with forskolin and IBMX, drugs that increase intracellular cAMP induced the promoter activity over the basal level. Intriguingly, beta-nafthoflavone, an arylhydrocarbon receptor ligand, induced the 20 beta-HSD promoter activity and is further evidenced by the induction of 20 beta-HSD expression in the livers of catfish, in vivo. These results demonstrate for the first time that 20 beta-HSD expression is not only modulated by cAMP but also by xenobiotics and further studies may provide significance to the ubiquitous distribution and broad substrate specificity of this enzyme. (C) 2012 Elsevier B.V. All rights reserved.