| Objective (1)To investigate the levels of insulin mRNA and MafA protein in distinct concentration of glucose, and observe the role of MafA in glucose regulating insulin gene expression. (2)To observe the levels of insulin mRNA and MafA protein in distinct concentration of GSK3 inhibitor, and investigate the effect of phosphorylated MafA on the insulin gene expression.Methods INS-1 cells were cultured in distinct concentration of glucose or GSK3 inhibitor for 24 hours. After that the expressions of MafA protein and insulin mRNA were detected by the method of Western blotting and RT-PCR respectively.Results (1)INS-1 cells were cultured in the glucose with the concentration of 3mmol/L, 7 mmol/L, 11.1 mmol/L and 20 mmol/L for 24h respectively. It was showed that, compared with the groups of low glucose(3mmol/L or 7mmol/L), total phosphorylated MafA (p-MafA) protein levels and insulin 2 mRNA levels descended significantly in the groups of high glucose (11.1mmol/L or 20mmol/L) (P<0. 05), while there were not significantly different in insulin 1 mRNA among them(P﹥0.05). (2)INS-1 cells were cultured in the GSK3 inhibitor with the concentration of 0μmol/L, 50μmol/L and 100μmol/L for 24h respectively. Compared with the control group (0μmol/L), the results showed that p-MafA protein levels and insulin 2 mRNA levels decreased in the groups of GSK3 inhibitor (50μmol/L or 100μmol/L) (P<0.05), hypophosphorylated MafA ascended significantly(P﹤0.01), and there were not significantly different in insulin 1 mRNA among them(P﹥0.05).Conclusion (1)Transcript factors MafA may regulate insulin 2 gene expression but not insulin 1 gene. (2)MafA may play an important role in glucose-regulated insulin gene expression. The glucotoxicity may reduce the expression of insulin 2 gene via the inhibition of MafA transcription. (3)GSK3 may activate insulin 2 gene expression by phosphorylating MafA in rat INS-1 cells. (4)MafA may activate insulin 2 gene transcription in the INS-1 cells. |
PDF Full Text Request