[Effect of insulin, cAMP, and dexamethasone on phosphoenolpyruvate carboxykinase gene promoter in vitro]

Abstract

Objective: To study the effect of insulin, cyclic adenosine monophosphate (cAMP), and dexamethasone (DEX) on 550 bp (-600 -/+ 69) fragment of phosphoenolpyruvate carboxykinase (PEPCK) gene promoter by reporter gene.

Methods: The recombinant pGL2-PEPCK-Luc and the control plasmid pSV-beta-Galactosidase were co-transfected to rat hepatoma cell line (CBRH7919) by lipofectin. By measuring luciferase activity, we evaluated in vitro regulation of PEPCK gene promoter on reporter gene transcription.

Results: cAMP and DEX stimulated PEPCK promoter obviously; meanwhile, they also had accumulative effects. At different physiological concentrations, insulin had a suppressive effect on PEPCK promoter, which was dose-independent.

Conclusion: There is a perfect feedback mechanism for PEPCK promoter in hepatoma cell. 550 bp (-600 -/+ 69) fragment of PEPCK may be a candidate gene in the gene therapy of diabetes.