Transcriptional activity of estrogen receptors ERα and ERβ in the EtC.1 cerebellar granule cell line
Transcriptional activity of estrogen receptors ERα and ERβ in the EtC.1 cerebellar granule cell line
复制标题
DOI：
10.1016/j.brainres.2007.10.033
复制
发表时间：
2007-12-19
期刊：
影响因子：
2.9
通讯作者：
Bulloch, Karen
中科院分区：
文献类型：
--
作者：
Gottfried-Blackmore, Andres;Croft, Gist;Bulloch, Karen
雌激素受体α和β（ERα和ERβ）在整个发育过程以及成年期的小脑中均有表达，这表明17β - 雌二醇（E2）在该脑结构中具有重要作用。在本研究中，我们通过用与雌激素反应元件启动子偶联的荧光素酶报告基因（ERE - Luc）转染未成熟小脑颗粒细胞系(EC)-C - t.1，对其表达的雌激素受体（ERs）的功能进行了表征。在正常细胞以及过表达人ERα或ERβ（hERα或hERβ）的细胞中，比较了E2和ER亚型选择性激动剂对(EC)-C - t.1细胞中荧光素酶活性的诱导作用。ER拮抗剂ICI 182,780（ICI）阻断了E2介导的报告基因转录，证明了功能性天然ERs的存在。与E2相比，ERα选择性激动剂（PPT）在荧光素酶诱导方面的反应降低。此外，ERβ激动剂（DPN）无法诱导荧光素酶活性。hERα的过表达并未增加E2诱导的ERE - Luc转录。相反，hERβ过表达降低了E2的功效，并消除了ERα选择性激动剂的活性。除非细胞中hERβ过表达，否则ERβ特异性激动剂不会诱导基因报告活性，这表明(EC)-C - t.1细胞中的内源性ERβ在转录上是无活性的。人ERs的过表达不影响ICI对E2反应的抑制作用。数据表明，在(EC)-C - t.1细胞中，ERα在E2介导的转录中起主要作用。我们结合其他暗示E2介导转录的复杂性和细胞类型特异性的报道对我们的数据进行了讨论。（c）2007爱思唯尔B.V.版权所有。
Estrogen receptors alpha and beta (ER alpha and ER beta) are expressed in the cerebellum throughout development and in the adult suggesting an important role of 17-beta-estradiol (E2) in this brain structure. In the present study, we have characterized the functionality of estrogen receptors (ERs) expressed in the immature cerebellar granule cell line (EC)-C-t.1 by transfecting such cells with a luciferase reporter gene (ERE-Luc) coupled to an estrogen response element promoter. The induction of luciferase activity in (EC)-C-t.1 cells by E2 and ER-subtype selective agonists was compared in normal cells and in cells overexpressing human ER alpha or ER beta (hER alpha or hER beta). E2-mediated transcription of the reporter gene was blocked by the ER antagonist ICI 182,780 (ICI), demonstrating the presence of functional native ERs. The selective agonist for ER alpha (PPT) showed a reduced response in luciferase induction compared to E2. Moreover, the ER beta agonist (DPN) was unable to induce luciferase activity. E2-induced ERE-Luc transcription was not increased by overexpression of hERa. In contrast, hER beta overexpression reduced the efficacy of E2 and abolished ER alpha-selective agonist activity. The ER beta-specific agonist did not induce gene reporter activity unless hER beta was overexpressed in the cells, suggesting that the endogenous ER beta in (EC)-C-t.1 cells is transcriptionally inactive. ICI inhibition of E2 responses was not affected by overexpression of the human ERs. The data suggest that ER alpha plays a predominant role in E2-mediated transcription in (EC)-C-t.1 cells. Our data are discussed in view of other reports alluding to the complexity and cell-type specificity of E2-mediated transcription. (c) 2007 Elsevier B.V. All rights reserved.