Yamamoto M, Sakuma T, Ichimaru H, Nemoto N
Department of Toxicology, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama, 930-0194, Japan.
J Biochem Mol Toxicol. 2001;15(2):76-82. doi: 10.1002/jbt.2.
The mouse Cyp2b-10 gene is inducible by treatment with estradiol as well as so-called phenobarbital (PB)-like inducers. To identify 5'-flanking elements responsible for induction by estradiol, we carried out reporter gene assays using a primary mouse hepatocyte culture system. Cyp2b-10 gene-driven luciferase activities were induced by estradiol as well as PB in this system. Deletion analysis demonstrated that the sequence contained within the region from -2331 bp to -2281 bp was responsible for the estradiol-induced luciferase activity. This region corresponds to the core element of PB-responsive enhancer module (PBREM). Several nucleotide mutations in the putative binding sites of the PBREM core element showed that the NR1 site was required for estradiol induction, and the same element was required for PB induction. These results indicate that estradiol induces Cyp2b-10 gene expression via PBREM.
小鼠Cyp2b - 10基因可通过雌二醇处理以及所谓的苯巴比妥（PB）样诱导剂诱导。为了鉴定负责雌二醇诱导的5'侧翼元件，我们使用原代小鼠肝细胞培养系统进行了报告基因检测。在该系统中，Cyp2b - 10基因驱动的荧光素酶活性可被雌二醇以及PB诱导。缺失分析表明，-2331 bp至-2281 bp区域内包含的序列负责雌二醇诱导的荧光素酶活性。该区域对应于PB反应增强子模块（PBREM）的核心元件。PBREM核心元件推定结合位点的几个核苷酸突变表明，NR1位点是雌二醇诱导所必需的，并且PB诱导也需要相同的元件。这些结果表明，雌二醇通过PBREM诱导Cyp2b - 10基因表达。
