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[目的]探讨Sp1转录因子在人肺腺癌细胞株A549中对survivin基因表达影响。[方法]电泳迁移率分析(EMSA)检测A549细胞核蛋白与标记的survivin启动子序列在有、无mithramycin时的结合情况。用不同浓度mithramycin处理A549细胞,RT-PCR检测survivin mRNA的表达。[结果]标记的survivin启动子序列-126bp～-106bp与核蛋白作用,出现DNA-核蛋白结合条带,经mithramycin预处理的相同序列出现减弱的DNA-核蛋白结合条带;序列-186bp～-166bp与核蛋白作用后无相应条带。mithramycin使A549细胞survivin mRNA表达显著下降。[结论]survivin启动子-121bp～-116bp处存在Sp1结合位点,mithramycin抑制Sp1与此位点的结合;-178bp～-175bp处可能不存在Sp1结合位点。mithramycin抑制survivin mRNA表达,抑制作用具有浓度依赖性。
[Objective] To investigate the effect of Sp1 transcription factor on survivin gene expression in human lung adenocarcinoma cell line A549. [Methods] Electrophoretic mobility shift assay (EMSA) was used to detect the binding of the A549 cell nuclear protein to the labeled survivin promoter in the presence or absence of mithramycin. A549 cells were treated with different concentrations of mithramycin, and the expression of survivin mRNA was detected by RT-PCR. [Results] The labeled survivin promoter sequence -126bp ~ -106bp interacted with the nucleoprotein, DNA-nucleoprotein binding band appeared, and the attenuated DNA-nucleoprotein binding band appeared in the same sequence pretreated with mithramycin. The sequence -186bp ~ There was no corresponding band between -166bp and nucleoprotein. mithramycin significantly decreased the expression of survivin mRNA in A549 cells. [Conclusion] The Sp1 binding site exists between -121bp and -116bp of survivin promoter, and mithramycin inhibits the binding of Sp1 to this site. The Sp1 binding site may not exist between -178bp and -175bp. mithramycin inhibited the expression of survivin mRNA in a concentration-dependent manner.