Department of Biochemistry and Biophysics, University of Rochester Medical School, Rochester, New York 14642, USA.
J Mol Endocrinol. 2012 Oct 30;49(3):249-66. doi: 10.1530/JME-12-0097. Print 2012 Dec.
17β-Estradiol (E(2)) plays important roles in functions of many tissues. E(2) effects are mediated by estrogen receptor (ER) α and β. ERs regulate transcriptions through estrogen-responsive element (ERE)-dependent and ERE-independent modes of action. ER binding to ERE constitutes the basis of the ERE-dependent pathway. Direct/indirect ER interactions with transcription complexes define ERE-independent signaling. ERs share functional features. Ligand-bound ERs nevertheless induce distinct transcription profiles. Live cell imaging indicates a dynamic nature of gene expressions by highly mobile ERs. However, the relative contribution of ER mobility at the ERE-independent pathway to the overall kinetics of ER mobility remains undefined. We used fluorescent recovery after a photo-bleaching approach to assess the ligand-mediated mobilities of ERE binding-defective ERs, ER(EBD). The decrease in ERα mobility with E(2) or the selective ER modulator 4-hydroxyl-tamoxifen (4HT) was largely due to the interaction of the receptor with ERE. Thus, ERα bound to E(2) or 4HT mediates transcriptions from the ERE-independent pathway with remarkably fast kinetics that contributes fractionally to the overall motility of the receptor. The antagonist Imperial Chemical Industries 182 780 immobilized ERαs. The mobilities of ERβ and ERβ(EBD) in the presence of ligands were indistinguishable kinetically. Thus, ERβ mobility is independent of the nature of ligands and the mode of interaction with target sites. Chimeric ERs indicated that the carboxyl-termini are critical regions for subtype-specific mobility. Therefore, while ERs are highly mobile molecules interacting with target sites with fast kinetics, an indication of the hit-and-run model of transcription, they differ mechanistically to modulate transcriptions.
17β-雌二醇（E2）在许多组织的功能中发挥着重要作用。E2 的作用是通过雌激素受体（ER）α和β介导的。ER 通过雌激素反应元件（ERE）依赖和 ERE 非依赖的作用模式调节转录。ER 与 ERE 的结合构成了 ERE 依赖途径的基础。ER 与转录复合物的直接/间接相互作用定义了 ERE 非依赖信号。ER 具有功能特征。配体结合的 ER 仍然诱导不同的转录谱。活细胞成像表明高度移动的 ER 通过基因表达具有动态性质。然而，ERE 非依赖途径中 ER 迁移的相对贡献对 ER 迁移的整体动力学仍然没有定义。我们使用光漂白后荧光恢复方法来评估 ERE 结合缺陷型 ER（ER（EBD））的配体介导的迁移率。E2 或选择性雌激素受体调节剂 4-羟基他莫昔芬（4HT）对 ERα 迁移率的降低主要是由于受体与 ERE 的相互作用。因此，与 E2 或 4HT 结合的 ERα 介导来自 ERE 非依赖途径的转录，其动力学非常快，这对受体的整体迁移率有分数贡献。拮抗剂 Imperial Chemical Industries 182 780 固定化 ERα。在配体存在下，ERβ 和 ERβ（EBD）的迁移率在动力学上无法区分。因此，ERβ 的迁移率与配体的性质和与靶位点相互作用的方式无关。嵌合 ER 表明羧基末端是亚型特异性迁移的关键区域。因此，虽然 ER 是高度移动的分子，与靶位点以快速动力学相互作用，表明转录的点击和跑模型，但它们在调节转录方面存在机制上的差异。
