转录因子Runx1对RPL4启动子的调节作用

Regulation of RPL4 promoter activity by transcription factor Runx1

目的:儿童白血病细胞全基因组芯片数据聚类分析发现,核糖体蛋白L4(ribosomal protein L4,RPL4)启动子区域具有转录因子Runx1的结合位点TTCATTCT,由此推测Runx1可能与该基因启动子之间存在调控作用。本研究通过观察Runx1蛋白与RPL4启动子之间的相互作用,了解Runx1对RPL4启动子转录活性的影响,探讨其在儿童白血病发生机制中的意义。方法:构建含RPL4启动子及其突变体的荧光素酶报告质粒,与Runx1的表达质粒共转染293T细胞,进行荧光素酶活性分析。结果:Runx1蛋白可使RPL4启动子的转录活性降低(P<0.01);随着Runx1剂量的增加,RPL4启动子的转录水平呈剂量依赖性降低(P<0.01);Runx1蛋白对RPL4启动子的突变体转录活性无调控作用(P>0.05)。结论:Runx1蛋白对RPL4启动子具有转录抑制作用,且具有明显的剂量依赖性;Runx1蛋白通过结合RPL4启动子区域的TTCATTCT位点发挥调控作用。

Objective： Previous genome-wide microarray analysis found TTCATTCT motif （DNA binding site of Runxl ） in the RPIA promoter of childhood leukemia cells, suggesting that Runxl may regulate the expression of RPIA. This study is to investigate the relationship between Runxl and RPL4 so as to better understand the effects of Runxl on RPL4gene transcription, laying a foundation for further studying leukemogenesis of childhood leukemia. Methods： The lu- ciferase plasmids containing RPIA promoter and its mutant were constructed and were co-transfected into 293T cells with the expression plasmid of Runxl. The transactivity of RPIA promoter was assayed by luminometer. Results ： Runxl signif- icantly decreased the transcriptional activity of RPIA promoter （P 〈 0.01 ）, and the decreasing degree was associated with the increase of Runxl dose （P 〈 0.01 ）. Runxl protein had no significant effect on the transcriptional activity of RPIA promoter mutant （ P 〉 0.05 ）. Conclusion： Runxl can inhibit RPIA gene transcription in a dose-dependent manner through binding to the TTCATTCT motif.