转录因子Dlx1和Dlx2在成釉细胞中调控MMP20启动子转录活性的研究

Transcription factor Dlx1 and Dlx2 regulate MMP20 expression in enameloblasts

目的:观察Dlx家族转录因子Dlx1和Dlx2对小鼠成釉细胞基质金属蛋白酶20(matrix metallo proteinase20,MMP20)基因的调控作用,初步确定Dlx家族在釉质发育中的作用。方法:构建Dlx1和Dlx2真核表达载体重组质粒,用双荧光素酶报告基因检测系统分析不同剂量的Dlx1和Dlx2对MMP20基因启动子转录活性的影响;确定Dlx1和Dlx2有明显作用的启动子区段,用基因定点突变和双荧光素酶报告基因检测系统分析Dlx1、Dlx2对MMP20基因启动子转录活性的影响,以及Dlx1、Dlx2在调控MMP20基因时的相互作用;最后观察Dlx1与Dlx2共转染时MMP20基因活性表达的变化。结果:Dlx1转染小鼠成釉细胞后MMP20启动子活性表达上调,Dlx2转染小鼠成釉细胞后MMP20启动子活性表达抑制;突变MMP20启动子的Dlx结合位点后,MMP20启动子的转录活性下降,而且Dlx1失去上调MMP20启动子转录活性的作用;当Dlx1与Dlx2共转染后,在Dlx1转染剂量不变的前提下,随着Dlx2转染量的增加,小鼠成釉细胞MMP20启动子转录活性显著增加。结论:Dlx1和Dlx2在釉质发育过程中有重要的生物学意义,对MMP20基因表达具有重要的调节作用。

AIM： To study the effects of transcription factor Dlxl and Dlx2 on the expressiong of matrix metalloproteinase20 （MMP20） in enameloblasts of mice. METHODS ： Recombinant plasmids of Dlxl and Dlx2 were reconstructed respectively by eukaryotic expression vector. The effect of Dlxl and Dlx2 on the transcription activity of MMP20 promoter and the promoter region of Dlxl and Dlx2 were detected by dual luciferase reporter assay. The interre- action of of Dlxl and Dlx2 on MMP20 expression was studied by binding sites direction mutation and Dual luciferase assay. The effect of cotransfection of Dlxl and Dlx2 on MMP20 expression was observed. RESULTS ： Dlxl transfec- tion upregulated while Dlx2 transfection downregulated MMP20 expression in enameloblasts. Mutation of Dlx binging site of MMP20 promoter the promoter transcription activity was declined and Dlxl lost the up-regulation role for tran- scription activity of MMP20 promoter. Cotransfection of Dlxl and Dlx2 the transcription activity of MMP20 promoter was increased with the increace of Dlx2 dose. CONCLUSION： Dlxl and Dlx2 PlaY a significant role in the rezulationof MMP20 expression in enameloblasts.