Transcriptional regulation of CYP2C9 gene -: Role of glucocorticoid receptor and constitutive androstane receptor
Transcriptional regulation of CYP2C9 gene -: Role of glucocorticoid receptor and constitutive androstane receptor
复制标题
DOI：
10.1074/jbc.m107228200
复制
发表时间：
2002-01-04
影响因子：
4.8
通讯作者：
Maurel, P
中科院分区：
文献类型：
--
作者：
Gerbal-Chaloin, S;Daujat, M;Maurel, P
虽然细胞色素P450 2C 9（CYP 2C 9）是成人肝脏中表达的主要酶，但其调节机制知之甚少。在以前的工作中，我们已经证明CYP 2C 9在原代人肝细胞中可被外源性药物（包括地塞米松、利福平和苯巴比妥）诱导。本研究的目的是研究控制CYP 2C 9诱导表达的分子机制。在各种激素核受体存在下对CYP 2C 9调节区（+21至-2088）的缺失分析表明存在两种功能性反应元件，糖皮质激素受体反应元件（-1648/-1684）和组成性雄烷受体反应元件（CAR，-1783/-1856）。每一种都通过共转染实验、定向诱变、凝胶迁移试验和对特异性拮抗剂RU 486和雄甾烷醇的反应来表征。通过这些实验，我们定位了糖皮质激素反应元件的不完全回文序列（-1662/-1676）和DR 4基序（-1803/-1818），它们分别被人糖皮质激素受体、hCAR和人肾上腺素X受体识别和反式激活。这些功能元件的鉴定为地塞米松（亚微摩尔浓度）、苯巴比妥和利福平分别诱导CYP 2C 9提供了合理的机制依据。因此，CYP 2C 9似乎是一种主要的糖皮质激素应答基因，此外，它可能通过CAR/甾烷X受体活化被外源性物质诱导。
Although cytochrome P450 2C9 (CYP2C9) is a major CYP expressed in the adult human liver, its mechanism of regulation is poorly known. In previous work, we have shown that CYP2C9 is inducible in primary human hepatocytes by xenobiotics including dexamethasone, rifampicin, and phenobarbital. The aim of this work was to investigate the molecular mechanism(s) controlling the inducible expression of CYP2C9. Deletional analysis of CYP2C9 regulatory region (+21 to -2088) in the presence of various hormone nuclear receptors suggested the presence of two functional response elements, a glucocorticoid receptor-responsive element (-1648/-1684) and a constitutive androstane receptor-responsive element (CAR, - 1783/-1856). Each of these were characterized by co-transfection experiments, directed mutagenesis, gel shift assays, and response to specific antagonists RU486 and androstanol. By these experiments we located a glucocorticoid-responsive element imperfect palindrome at -1662/-1676, and a DR4 motif at -1803/-1818 recognized and transactivated by human glucocorticoid receptor and by hCAR and pregnane X receptor, respectively. Identification of these functional elements provides rational mechanistic basis for CYP2C9 induction by dexamethasone (submicromolar concentrations), and by phenobarbital and rifampicin, respectively. CYP2C9 appears therefore to be a primary glucocorticoid-responsive gene, which in addition, may be induced by xenobiotics through CAR/pregnane X receptor activation.