Abstract:Gene targeting is a new molecular biology technique, which introduces heritable genetic modification on the basis of DNA homologous recombination. Compared with classic approaches, homologous recombination using a promoter trap vector could yield higher targeting frequencies. It is very important for the correct expression of exogenous gene. In this study, neor gene was amplified by PCR technology from plasmid pIRES2-EGFP and BamHⅠ and BglⅡ restriction enzyme sites were added to the upstream and downstream, respectively; then the PCR fragment was cloned into pMD19-T simple Vector, named pMD-neo. Plasmids pMD-neo and pEGFP-C1 were digested by BamHⅠ and BglⅡ, and ligated together to obtain intermediate plasmid pEGFP-neo. Then pEGFP-neo and pIRES2-EGFP were digested by Bsp1407Ⅰ and SfiⅠto constitute another intermediate plasmid pIRES-EGFPneo. At last, multiple cloning sites (MCS) were added to pIRES-EGFPneo after digestion of pIRES-EGFPneo and pMD-MCS with BamHⅠand MluⅠ, and the final gene trap vector pMCS-IEN was constituted. To test the expression of green fluorescence protein (GFP) and G418 resistance gene, the PGK promoter was added to the upstream of MCS of the pMCS-IEN and the reconstitute plasmid was transfected to Hela cells. GFP and G418 resistance colonies were obtained after screening by microscopy and G418 selection. When the homologous arms were inserted into the basic vector pMCS-IEN and formed the promoter trap vector,it could be used to target the objective gene. Therefore, this vector will become a useful tool to generate gene modification animals.
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