Lee Sang-Hyeon, Jang Min-Kyung, Kim Ok-Soo, Lee Ok-Hee, Kim Nam Young, Yoo Ki-Hwan, Lee Dong-Geun, Shong Young Hwa, Mouradian M Maral
Department of Bioscience and Biotechnology, Silla University, Gwaebop-dong, Sasang-Gu, Busan, Republic of Korea.
J Steroid Biochem Mol Biol. 2009 May;115(1-2):30-5. doi: 10.1016/j.jsbmb.2009.02.013. Epub 2009 Mar 4.
Steroid hormones, especially glucocorticoids, exert physiologic effects on dopaminergic neurotransmission and have been implicated in several dopamine-mediated neuropsychiatric conditions. D(2) dopamine receptor gene expression is regulated by the zinc finger-type nuclear protein GDNF-inducible transcription factor (GIF). In this study, we sought to investigate if steroids could regulate transcription of the GIF gene itself. Transient co-transfection of the D(2) expressing neuroblastoma cell line NB41A3 with GIF promoter-luciferase constructs along with expression vectors for steroid hormone receptors showed that activation of glucocorticoid receptors but not estrogen receptors up-regulates transcription from the GIF promoter 5.0-fold. Progesterone receptors, which share the same consensus DNA recognition sequence as glucocorticoid receptors, also activated the GIF promoter. Serial 5'-deletion mutants of the GIF gene upstream region localized the glucocorticoid-responsive segment between nucleotides -128 and -66 relative to the transcription start site. This region contains a putative glucocorticoid-responsive element/progesterone-responsive element (GRE/PRE). Additionally, this fragment of the GIF gene 5'-upstream region activated the heterologous herpes simplex virus thymidine kinase (TK) promoter, which is known to be glucocorticoid and progesterone responsive. Furthermore, glucocorticoid receptor activation up-regulated endogenous GIF gene mRNA expression in NB41A3 cells. These observations demonstrate a molecular basis for glucocorticoid and progesterone-induced up-regulation of GIF gene transcription and provide a mechanism for the modulation of dopamine-mediated behaviors by these hormones.
类固醇激素，尤其是糖皮质激素，对多巴胺能神经传递发挥生理作用，并与多种多巴胺介导的神经精神疾病有关。D(2)多巴胺受体基因表达受锌指型核蛋白胶质细胞源性神经营养因子诱导转录因子（GIF）调控。在本研究中，我们试图探究类固醇是否能调节GIF基因自身的转录。将表达D(2)的神经母细胞瘤细胞系NB41A3与GIF启动子-荧光素酶构建体以及类固醇激素受体表达载体进行瞬时共转染，结果显示糖皮质激素受体而非雌激素受体的激活可使GIF启动子的转录上调5.0倍。与糖皮质激素受体具有相同共有DNA识别序列的孕激素受体也能激活GIF启动子。对GIF基因上游区域进行一系列5'-缺失突变，将糖皮质激素反应区段定位在相对于转录起始位点的核苷酸-128至-66之间。该区域包含一个假定的糖皮质激素反应元件/孕激素反应元件（GRE/PRE）。此外，GIF基因5'-上游区域的这一片段激活了已知对糖皮质激素和孕激素有反应的异源单纯疱疹病毒胸苷激酶（TK）启动子。此外，糖皮质激素受体激活上调了NB41A3细胞中内源性GIF基因mRNA的表达。这些观察结果证明了糖皮质激素和孕激素诱导GIF基因转录上调的分子基础，并为这些激素调节多巴胺介导的行为提供了一种机制。
