Objective To explore the role of histone modification in the MafA gene transcription expression and to comparing the differences of histone modifications of MafA genes promoter in various cell types of mouse.Method The promoter histone modification status of MafA and MLH1 genes in NIT-1 cells, NIH3T3 cells and mouse embryonic stem cells were measured by chromatin immunoprecipitation-real time PCR methods.The expression of these genes in the three cell lines were measured by realtime RT-PCR.The relation between histone modifications and genes expressions were analysed.Result (1)Compared with mES cell,there were higher H3K4m3 and lower H3K9m3 modification levels in the promoter of MafA gene in NIT-1 cell( P ＜ 0.05).There were higher H3K9m3 and lower H3K4m3 modification levels in the promoter of MafA gene in NIH3T3 cells( P ＜ 0.05 ).(2) MafA gene transcription expressed only in NIT-1 cells.There was the Pearson correlation between MafA gene expression and H3K4m3 modification( Coef.0.995).And Pearson correlation was also between MafA gene expression and H3 K9m3 modification ( Coef.- 0.751 ).(3) There was not correlation between housekeeper MLH1 genes expression and histone modification.Conclusion H3K4m3 and H3K9m3 modification could coordinated participate to regulation and control expression of MafA gene.It is great significant to the differentiation of β cells from ES cells.%目的 通过比较不同细胞类型之间MafA基因转录起始区的组蛋白修饰差异,探讨组蛋白修饰对MafA基因转录表达的作用.方法 采用染色质免疫共沉淀一实时定量PCR法检测小鼠胰岛素瘤β细胞(NIT-1)、NIH小鼠成纤维细胞(NIH3T3)及小鼠胚胎干细胞(mES)三者中的MafA和MLH1基因转录起始区组蛋白修饰(H3K4m3、H3K9m3和H3乙酰化)的状况.同时采用实时定量RT-PCR检测上述三种细胞各基因mRNA表达水平.分析基因的H3K4m3、H3K9m3和H3乙酰化修饰与基因表达之间的相互关系.结果 (1)以mES细胞为参照,NIT-1细胞MafA基因的转录起始区的H3K4m3修饰水平明显增高(P＜0.05),H3K9m3修饰水平明显降低(P＜0.05);NIH 3T3细胞MafA基因的转录起始区的H3K9m3修饰水平明显增高(P＜0.05),H3K4m3修饰水平明显降低(P＜0.05);(2)MafA基因的仅在NIT-1细胞表达,其表达与H3K4m3修饰存在直线相关(相关系数0.995);与H3K9m3修饰存在直线负相关(相关系数-0.751);(3)管家基因MLH1的表达与所检测组蛋白修饰无相关性.结论 H3K9m3与H3K4m3修饰能相互协调,共同调控MafA基因的表达,对胚胎干细胞向β细胞分化具有重要的意义.
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