Expression of the human insulin gene in the gastric G cells of transgenic mice

The goal of this study was to engineer gastrin-producing G cells of the gas tric antrum to produce insulin. A pGas-Ins chimeric gene in which the gastr in promoter drives expression of the human insulin gene was constructed and was validated by transient transfection of GH4 and AGS cells. RT-PCR analy sis and sequencing revealed three forms of differentially spliced insulin m RNA in GH4 cells transiently transfected by pGas-Ins. Gas-Ins transgenic mi ce were generated utilizing this chimeric gene. Northern blot analysis, in situ hybridization, and immunohistochemistry demonstrated expression of the human insulin gene specifically in antral G cells. Northern blot analysis demonstrated that the shortest of the insulin mRNA three forms is predomina ntly expressed in stomach tissue. RT-PCR analysis also showed expression of the transgene in colon, pancreas, and brain tissues that was undetectable by northern analysis. We conclude that gastrin promoter can be used for tar geting expression of human insulin to antral G cells and that antral G cell s can express human insulin. Further refining of the chimeric gene design i s required to enhance expression.