A Tcf/Lef element within the enhancer region of the human NANOG gene plays a role in promoter activation
A Tcf/Lef element within the enhancer region of the human NANOG gene plays a role in promoter activation
复制标题
DOI：
10.1016/j.bbrc.2011.06.044
复制
发表时间：
2011-07-08
影响因子：
3.1
通讯作者：
Shin, Soon Young
中科院分区：
文献类型：
--
作者：
Kim, Chang Gun;Chung, Il-Yup;Shin, Soon Young
NANOG是一种含有同源结构域的转录因子，对于维持胚胎干细胞的多能性和自我更新至关重要。然而，在人类细胞中调节NANOG表达的分子机制在很大程度上仍然未知。在这里，我们研究了Tcf/Lef反应元件位于人NANOG基因的增强子中的作用。我们发现，Lef 1或β-catenin的强制表达刺激人NANOG启动子活性，而shRNA介导的β-catenin敲低降低Lef 1诱导的NANOG启动子激活。在人NANOG基因的增强子区域内的Tcf/Lef元件的缺失或突变完全废除了Lef 1诱导的NANOG启动子活性。染色质免疫沉淀分析的结果表明，Lefl和β-连环蛋白结合到NANOG基因的增强子区域中的Tcf/Lef元件。GSK-31的强制表达抑制基础的、Lefl诱导的和β-连环蛋白诱导的NANOG启动子活性，而用GSK-3 β抑制剂SB 216763处理导致β-连环蛋白和NANOG蛋白的积累。此外，DvI-1诱导的NANOG启动子活性被β-连环蛋白shRNA的表达所废除。Dvl-1的稳定过表达导致β-连环蛋白和NANOG积累。这些结果表明，在人NANOG基因的增强子区域中的Tcf/Lef响应元件能够刺激NANOG基因转录。(C)2011 Elsevier Inc. All rights reserved.
NANOG is a homeodomain-containing transcription factor that is essential for the maintenance of pluripotency and self-renewal in embryonic stem cells. However, the molecular mechanisms underlying the regulation of NANOG expression in human cells remain largely unknown. Here, we investigated the role of Tcf/Lef response elements located in the enhancer of the human NANOG gene. We found that forced expression of Lef1 or beta-catenin stimulated human NANOG promoter activity, while shRNA-mediated knockdown of beta-catenin reduced Lef1-induced NANOG promoter activation. Deletion or mutation of the Tcf/Lef element within the enhancer region of the human NANOG gene completely abrogated Lef1-induced NANOG promoter activity. The results of a chromatin immunoprecipitation assay demonstrated that Lefl and beta-catenin bind to the Tcf/Lef element in the enhancer region of the NANOG gene. Forced expression of GSK-31 inhibited basal, Lefl -induced, and beta-catenin-induced NANOG promoter activity, while treatment with the GSK-3 beta inhibitor SB216763 resulted in the accumulation of beta-catenin and NANOG protein. Furthermore, DvI-1-induced NANOG promoter activity was abrogated by the expression of beta-catenin shRNA. Stable overexpression of Dvl-1 caused beta-catenin and NANOG to accumulate. These results indicate that the Tcf/Lef response element in the enhancer region of the human NANOG gene is able to stimulate NANOG gene transcription. (C) 2011 Elsevier Inc. All rights reserved.