Generation Of Islet β Cell-specific Cre Transgenic Mice By Gene Targeting

β-cell is a major source of insulin. Tightly controlled insulin secretion bypancreatic β-cells is critical to the maintenance of glucose homeostasis, thedysfunction of which is a central component of the pathogenesis of type2diabetes.However, the regulatory mechanism of β-cells physiological and pathological processof β-cell is still largely unknown. Research on drug therapy of diabetes is mainlyfocus on β-cell.Conditional gene knockout is a new strategy to study gene function.Inconditional gene targeting system with Cre/LoxP recombination，the importantfunctional domains of targeting gene were floxed by two LoxP sites，usually beinginserted into some introns．And therefore Conditional knockout mice show normalphenotype．After mating with mice with special Cre expression in some cells ortissue，target gene will be deleted by Cre/LoxP recombination in the specificregion．The gene will be kept intact expression in other tissues．So it is a good way tostudy the function of some genes with deletion-lethality during embryo development.In our research, we constructed a gene knock-in targeting vector which containsCre recombinase that specific expresses in β-cell. It provides the key material forgene specific knockout mice model in β-cell. Through a first homologousrecombination, we cloned about12kb genomic DNA fragment from BAC whichcontains Ins2genomic DNA into a low copy vector pBR322-2s through gap repair.Meantime, a mini-targeting vector contains internal ribosome entry site (IRES),DNA sequences encoding Cre recombinase and positive-negative-selection (PNS)gene was constructed. After second homologous recombination, the finalIns2-IRES-Cre targeting vector was generated. The vector will be an importantmaterial for the animal model of Cre recmobinase which specific expressed in β-cell.