Li X R, Chong A S, Wu J, Roebuck K A, Kumar A, Parrillo J E, Rapp U R, Kimberly R P, Williams J W, Xu X
Department of General Surgery, Rush Presbyterian St. Luke's Medical Center, Chicago, Illinois 60612, USA.
J Biol Chem. 1999 Dec 3;274(49):35203-10. doi: 10.1074/jbc.274.49.35203.
Fas (CD95 or APO-1), a transmembrane cell surface receptor of the tumor necrosis factor receptor family, is up-regulated in activated T lymphocytes. Our present study identified an upstream enhancer element (between nucleotide positions -862 and -682) containing a GA-binding protein (GABP) site and a low affinity activating protein-1 (AP-1)-binding site. T cell activation increased the DNA binding of GABP and AP-1 to this enhancer site. The specificity of GABP and AP-1 binding was demonstrated by competition electrophoretic mobility shift assay and supershift electrophoretic mobility shift assay with antibodies against GABP and AP-1, respectively. Mutational analysis of Fas promoter revealed that both GABP- and AP-1-binding sites were required for initiating Fas gene transcription. We further show that anti-CD3 mAb, phorbol 12-myristate 13-acetate, and phorbol 12-myristate 13-acetate/ionomycin strongly activated promoters carrying multiple copies of the Fas enhancer, and mutation of either the GABP or AP-1 binding site severely reduced transcriptional activity. Taken together, these results suggest that the transcription factors GABP and AP-1 play a critical role in the induction of Fas gene expression in T cell antigen receptor.CD3-stimulated Jurkat cells.
Fas（CD95或APO-1）是肿瘤坏死因子受体家族的一种跨膜细胞表面受体，在活化的T淋巴细胞中上调。我们目前的研究鉴定出一个上游增强子元件（核苷酸位置-862至-682之间），其含有一个GA结合蛋白（GABP）位点和一个低亲和力活化蛋白-1（AP-1）结合位点。T细胞活化增加了GABP和AP-1与该增强子位点的DNA结合。分别用针对GABP和AP-1的抗体进行竞争电泳迁移率变动分析和超迁移电泳迁移率变动分析，证实了GABP和AP-1结合的特异性。Fas启动子的突变分析表明，GABP结合位点和AP-1结合位点都是启动Fas基因转录所必需的。我们进一步表明，抗CD3单克隆抗体、佛波醇12-肉豆蔻酸酯13-乙酸酯以及佛波醇12-肉豆蔻酸酯13-乙酸酯/离子霉素强烈激活携带多个Fas增强子拷贝的启动子，并且GABP或AP-1结合位点的突变会严重降低转录活性。综上所述，这些结果表明转录因子GABP和AP-1在T细胞抗原受体CD3刺激的Jurkat细胞中Fas基因表达的诱导中起关键作用。
