Hayakawa Morisada, Yanagisawa Ken, Aoki Shinsuke, Hayakawa Hiroko, Takezako Naoki, Tominaga Shin-ichi
Department of Biochemistry, Jichi Medical School, 3311-1 Yakushiji, Minamikawachi-machi, Kawachi-gun, Tochigi 329-0498, Japan.
Biochim Biophys Acta. 2005 Apr 5;1728(1-2):53-64. doi: 10.1016/j.bbaexp.2005.01.012.
ST2 is a member of the interleukin-1 receptor family and is expressed in type-2 T helper (Th2) cells. Here, we have studied the molecular mechanism responsible for the transcriptional regulation of the ST2 gene in Th2 cells using a mouse thymoma cell line, EL-4. The ST2 gene has distal and proximal promoters. ST2 mRNA was produced from the distal promoter in EL-4 cells stimulated with both phorbol 12-myristate 13-acetate (PMA) and dibutyryl cAMP (Bt2cAMP). The region of approximately 100 bp upstream of transcription start site, containing two GATA consensus sites, was indispensable for the activation of the distal promoter in reporter gene analysis. An electrophoretic mobility shift assay showed that transcription factor GATA-3 bound one of the GATA consensus sites (from -84 to -79) with nuclear extracts from PMA plus Bt2cAMP-stimulated EL-4 cells. The overexpression of GATA-3 enhanced the activity of the distal promoter. On the other hand, mutations of the GATA consensus site canceled out the enhancement by GATA-3. These data suggest that GATA-3 is an important transcription factor for the expression of the ST2 gene in Th2 cells.
ST2是白细胞介素-1受体家族的成员，在2型辅助性T（Th2）细胞中表达。在此，我们利用小鼠胸腺瘤细胞系EL-4研究了Th2细胞中ST2基因转录调控的分子机制。ST2基因有远端和近端启动子。在用佛波酯12-肉豆蔻酸酯13-乙酸酯（PMA）和二丁酰环磷腺苷（Bt2cAMP）刺激的EL-4细胞中，ST2 mRNA由远端启动子产生。在报告基因分析中，转录起始位点上游约100 bp的区域，包含两个GATA共有位点，对于远端启动子的激活是必不可少的。电泳迁移率变动分析表明，转录因子GATA-3与PMA加Bt2cAMP刺激的EL-4细胞核提取物结合在其中一个GATA共有位点（从-84到-79）上。GATA-3的过表达增强了远端启动子的活性。另一方面，GATA共有位点的突变消除了GATA-3的增强作用。这些数据表明，GATA-3是Th2细胞中ST2基因表达的重要转录因子。
