Construction of a HERG mutant L539fs/47-*558W pEGFP vector and the expression of the fusion protein in HEK293 cells

ObjectiveTo construct a human ether-a-go-go-related gene (HERG) nonsense mutant L539fs/47-*558W into the autonomously fluorescent, eukaryotic expression vector pEGFP-C2, and to verify expression of the reconstruct in human embryonic kidney-293 (HEK293) cells.MethodsThe mutational fragment was subcloned into pEGFP-C2-HERG by double digestion of Sbf I, Eco91 I and rejoining of T4 ligase. After verification, the recombinant pEGFP-C2-L539fs/47-*558W and pEGFP-C2-HERG were respectively transfected into HEK293 cells for 48 h by the Lipofect method to observe the expression location of the fusion protein by laser confocal imaging scanning in vivo. pcDNA3 -L539fs/47-*558W and pcDNA3-HERG were transfected to observe the expression location of the HERG protein by immunofluoresceoce. The mutant protein size was determined by Western blotting.ResultsThe about 1 kb-sized mutation region cDNA fragment from pcDNA3-L539fs/47-*558W and the about 7.2 kb-sized target vector fragment from pcDNA3-HERG were ligated after purification and gel recovery. pEGFP-C2-L539fs/47*-558W, approximately 8.2 kb, was demonstrated successfully been constructed under agarose gel electrophoresis and further sequencing. Laser confocal imaging showed that pEGFP-C2-HERG was mainly expressed in the membrane, whereas truncated mutant-type HERG in the pEGFP-C2 vector was partially located in the cytoplasm, the others were transported to the cell membrane in living HEK293 cells. The same as the immunofluoresceoce results after transfection of pcDNA3-HERG and pcDNA3-L539fs/47-558W. Wild-type HERG-GFP fusion protein expressed 160 and 180 kDa bands. The mutant and mutant-GFP fusion proteins were 70 and 100 kDa, respectively.ConclusionpEGFP-C2-L539fs/47-*558W was successfully constructed by double digestion method GFP had no effect on its protein expression and trafficking in HEK293 cells, which laid a foundation for the further study on L539fs/47-*558W.