Department of Medical Biochemistry and Molecular Biology, Saarland University Medical Faculty, D-66421 Homburg, Germany.
Department of Medical Biochemistry and Molecular Biology, Saarland University Medical Faculty, D-66421 Homburg, Germany.
Gene. 2018 Jun 5;658:70-75. doi: 10.1016/j.gene.2018.03.008. Epub 2018 Mar 5.
The polyphenol resveratrol is found in many plant and fruits and is a constituent of our diet. Resveratrol has been proposed to have chemopreventive and anti-inflammatory activities. On the cellular level, resveratrol activates stimulus-regulated transcription factors. To identify resveratrol-responsive elements within a natural gene promoter, the molecular pathway leading to c-Fos gene expression by resveratrol was dissected. The c-Fos gene encodes a basic region leucine zipper transcription factor and is a prototype of an immediate-early gene that is regulated by a wide range of signaling molecules. We analyzed chromatin-integrated c-Fos promoter-luciferase reporter genes where transcription factor binding sites were destroyed by point mutations or deletion mutagenesis. The results show that mutation of the binding sites for serum response factor (SRF), activator protein-1 (AP-1) and cAMP response element binding protein (CREB) significantly reduced reporter gene transcription following stimulation of the cells with resveratrol. Inactivation of the binding sites for signal transducer and activator of transcription (STAT) or ternary complex factors did not influence resveratrol-regulated c-Fos promoter activity. Thus, the c-Fos promoter contains three resveratrol-responsive elements, the cAMP response element (CRE), and the binding sites for SRF and AP-1. Moreover, we show that the transcriptional activation potential of the c-Fos protein is increased in resveratrol-stimulated cells, indicating that the biological activity of c-Fos is elevated by resveratrol stimulation. Pharmacological and genetic experiments revealed that the protein kinase ERK1/2 is the signal transducer that connects resveratrol treatment with the c-Fos gene.
多酚白藜芦醇存在于许多植物和水果中,是我们饮食的组成部分。白藜芦醇具有化学预防和抗炎活性。在细胞水平上,白藜芦醇激活刺激调节转录因子。为了在天然基因启动子内鉴定白藜芦醇反应元件,解析了白藜芦醇诱导 c-Fos 基因表达的分子途径。c-Fos 基因编码碱性区域亮氨酸拉链转录因子,是受广泛信号分子调节的即时早期基因的原型。我们分析了染色质整合的 c-Fos 启动子-荧光素酶报告基因,其中转录因子结合位点通过点突变或缺失诱变被破坏。结果表明,血清反应因子 (SRF)、激活蛋白-1 (AP-1) 和 cAMP 反应元件结合蛋白 (CREB) 的结合位点突变显著降低了细胞用白藜芦醇刺激后的报告基因转录。信号转导和转录激活因子 (STAT) 或三元复合物因子结合位点的失活不影响白藜芦醇调节的 c-Fos 启动子活性。因此,c-Fos 启动子包含三个白藜芦醇反应元件,即 cAMP 反应元件 (CRE) 以及 SRF 和 AP-1 的结合位点。此外,我们表明,在白藜芦醇刺激的细胞中,c-Fos 蛋白的转录激活潜力增加,表明 c-Fos 的生物学活性通过白藜芦醇刺激而升高。药理学和遗传学实验表明,蛋白激酶 ERK1/2 是将白藜芦醇处理与 c-Fos 基因连接的信号转导物。