Functional characterization of the promoter of human carbonyl reductase 1 (CBR1).: Role of XRE elements in mediating the induction of CBR1 by Ligands of the aryl hydrocarbon receptor
Functional characterization of the promoter of human carbonyl reductase 1 (CBR1).: Role of XRE elements in mediating the induction of CBR1 by Ligands of the aryl hydrocarbon receptor
复制标题
DOI：
10.1124/mol.107.035550
复制
发表时间：
2007-09-01
影响因子：
3.6
通讯作者：
Blanco, Javier G.
中科院分区：
文献类型：
--
作者：
Lakhman, Sukhwinder S.;Chen, Xiaomin;Blanco, Javier G.
人羰基还原酶1（CBR 1）代谢多种底物，包括抗癌药物阿霉素和抗精神病药物氟哌啶醇。CBR 1的转录调控在很大程度上尚未探索。因此，我们首先研究了包含CBR 1翻译起始位点上游2.4个酶的渐进式基因报告构建体的启动子活性。接下来，我们研究了在与原型受体激活剂（例如，例如，在一个实施例中，地塞米松和利福平）。CBR 1 mRNA水平显著诱导（5倍）的芳烃受体（AHR）β-萘酚酮的配体。DNA序列分析表明，两个外源反应元件（-122XRE和-5783XRE）具有潜在的调控功能。缺乏-122XRE的CBR 1启动子构建体在用β-萘甲酮孵育的AHR-熟练细胞中显示降低的9倍启动子活性。将-5783XRE融合到（-2485）CBR 1报告基因构建体上，在与β-萘甲酮孵育后，其启动子活性增强了5倍。此外，我们测试了有效的AHR配体2，3，7，8-四氯二苯并对二恶英（TCDD）是否诱导Ahr（+/-）和Ahr（-/-）小鼠中Cbr 1的表达。与注射溶剂的对照组相比，TCDD诱导Ahr（+/-）小鼠肝脏Cbr 1 mRNA（TCDD，2倍）和Cbr 1蛋白水平（TCDD，2倍）。与此相反，没有显着的Cbr 1 mRNA和Cbr 1蛋白的诱导检测Ahr（+/-）小鼠用TCDD治疗的肝脏。这些研究提供了关于人类CBR 1基因启动子的功能特征的第一个见解。我们的数据表明，AHR途径有助于CBR 1的转录调控。
Human carbonyl reductase 1 (CBR1) metabolizes a variety of substrates, including the anticancer doxorubicin and the antipsychotic haloperidol. The transcriptional regulation of CBR1 has been largely unexplored. Therefore, we first investigated the promoter activities of progressive gene-reporter constructs encompassing up to 2.4 kilobases upstream of the translation start site of CBR1. Next, we investigated whether CBR1 mRNA levels were altered in cells incubated with prototypical receptor activators (e. g., dexamethasone and rifampicin). CBR1 mRNA levels were significantly induced (5-fold) by the ligand of the aryl hydrocarbon receptor (AHR) beta- naphthoflavone. DNA sequence analysis revealed two xenobiotic response elements (-122XRE and -5783XRE) with potential regulatory functions. CBR1 promoter constructs lacking the -122XRE showed diminished 9-fold) promoter activity in AHR-proficient cells incubated with beta-naphthoflavone. Fusion of -5783XRE to the (-2485)CBR1 reporter construct enhanced its promoter activity after incubations with beta-naphthoflavone by 5-fold. Furthermore, we tested whether the potent AHR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin ( TCDD) induced Cbr1 expression in Ahr(+/-) and Ahr(-/-) mice. TCDD induced hepatic Cbr1 mRNA ( TCDD, 2-fold) and Cbr1 protein levels ( TCDD, 2-fold) in Ahr(+/-) mice compared with vehicle-injected controls. In contrast, no significant Cbr1 mRNA and Cbr1 protein induction was detected in livers from Ahr(+/-) mice treated with TCDD. These studies provide the first insights on the functional characteristics of the human CBR1 gene promoter. Our data indicate that the AHR pathway contributes to the transcriptional regulation of CBR1.