Studies On The Role Of DNA Methylation In The Islet-tissue Specific Genes Expression And The Differentiation Of Islet Cells

Objective:The investigate on the role of DNA methylation in the islet-tissue specific genes expression and the differentiation of islet cells.Comparing the differences expression of these genes DNA methylation status in various cell types.Methods:The promoter methylation status of 5 genes(Pdx-1,Pax4,MafA,Nkx6.1 and Insulin) in NIT1 cells,NIH3T3 cells and mouse ES cells were measured by using methylated DNA immunoprecipitation methods(MeDIP-qPCR).The expression of these genes in the three cell lines were measured by realtime RT-PCR.Result:The promoter methylation status of Pdx-1,MafA and Nkx6.1 gene in NIH3T3 cells were significantly higher(high extent of methylaion) than that of the other two cell lines(low extent of methylaion)(P＜0.05).The promoter methylation status of Pax4 and Insulin gene were more low in these three cell lines.There was not a statistical difference in the promoter methylation status about Pax4 gene between NIH3T3 ceils and NIT1 cells(P＞0.05).The promoter methylation status of Insulin gene had not measured in NIH3T3 cells,it also was lower than that of NIT1 cells(P＜0.05).In the other hand,all five genes were highly expression in NIT1 cells,but not in both of NIH3T3 cells and mES cells.This result shows that high extent of promoter methylation in NIH3T3 ceils are not expressing Pdx-1,MafA and Nkx6.1 gene;on the contrary,the NIT1 cells with low extent of promoter methylation are highly expression of these genes.But it is not correlation between Pax4 and Insulin gene in the cell lines.The extent of promoter methylation for all five genes in mES cells were very low,however,the expression of these genes were negative in MES cells.Conclusion:DNA methylation participated to regulation and control expression of islet-tissue specific genes and play a important role on the differentiation of islet cells from ES cells.