Kanno Masafumi, Yazawa Takashi, Kawabe Shinya, Imamichi Yoshitaka, Usami Yoko, Ju Yunfeng, Matsumura Takehiro, Mizutani Tetsuya, Fujieda Shigeharu, Miyamoto Kaoru
Department of Biochemistry, University of Fukui, Fukui 910-1193, Japan; Division of Otorhinolaryngology Head and Neck Surgery, Department of Sensory and Locomotor Medicine, Faculty of Medical Sciences, University of Fukui, Fukui 910-1193, Japan.
Department of Biochemistry, University of Fukui, Fukui 910-1193, Japan; Translational Research Center, Organization for Life Science Advancement Programs, University of Fukui, Fukui 910-1193, Japan; Department of Biochemistry, Asahikawa Medical University, Hokkaido 078-8510, Japan.
Biochim Biophys Acta. 2014 May;1839(5):406-14. doi: 10.1016/j.bbagrm.2014.03.016. Epub 2014 Apr 3.
Pluripotent stem cells maintain their pluripotency and undifferentiated status through a network of transcription factors. Liver receptor homolog-1 (Lrh-1) is one of these, and regulates the expression of other important transcription factors such as Oct-3/4 and Nanog. In early embryo and embryonic stem (ES) cells, Lrh-1 is transcribed using a unique promoter. In this study, we investigated the transcriptional regulation of embryonic Lrh-1 using ES and embryonal carcinoma F9 cells. Reporter assays, electrophoretic mobility shift assays, and chromatin immunoprecipitation assays demonstrated that Sox2 and Gabp proteins bind to the promoter region of embryonic Lrh-1, and are necessary for its activation. The Sox2 site showed strong promoter activity and affinity for protein binding. Upon differentiation into the parietal endoderm by retinoic acid and cAMP, Lrh-1 promoter activity and transcripts were markedly reduced within 24 h. At the same time, Sox2 and Gabp binding to the promoter region of Lrh-1 were decreased, followed by a reduction of their expression. These results indicate that embryonic Lrh-1 expression is regulated by both Sox2 and Gabp. Our study presents new insights into the transcription factor network of pluripotent stem cells.
多能干细胞通过转录因子网络维持其多能性和未分化状态。肝受体同源物1（Lrh-1）就是其中之一，它调节其他重要转录因子如Oct-3/4和Nanog的表达。在早期胚胎和胚胎干细胞（ES细胞）中，Lrh-1是使用独特的启动子进行转录的。在本研究中，我们使用ES细胞和胚胎癌细胞F9研究了胚胎Lrh-1的转录调控。报告基因检测、电泳迁移率变动分析和染色质免疫沉淀分析表明，Sox2和Gabp蛋白与胚胎Lrh-1的启动子区域结合，并且是其激活所必需的。Sox2位点显示出强大的启动子活性和对蛋白质结合的亲和力。在用视黄酸和cAMP诱导分化为滋养层内胚层后，Lrh-1启动子活性和转录本在24小时内显著降低。同时，Sox2和Gabp与Lrh-1启动子区域的结合减少，随后它们的表达也降低。这些结果表明，胚胎Lrh-1的表达受Sox2和Gabp两者的调控。我们的研究为多能干细胞的转录因子网络提供了新的见解。
