Abstract:To construct a bicistronic expression vector pcDNA3.1AB controlled by two CMV promoters,pcDNA3.1A and pcDNA3.1B were constructed first by reforming the MCS of pcDNA3.1(+).The PCR product of-PCMV-MCS-BGHpolyA-from pcDNA3.1A was inserted into pcDNA3.1B to form pcDNA3.1AB.DsRed gene and EGFP gene were inserted into pcDNA3.1AB to construct pcDNA-DsRed,pcDNA-EGFP and pcDNA-DsRed-EGFP.The recombinants were transfected and transiently expressed in COS-7 cells and detected by fluorescence microscope. DsRed and EGFP were coexpress in pcDNA-EGFP-DsRed, and the fluorescence intensity had no significant deviation.The fluorescence intensity was similar between monocistronic and bicistronic vectors.The successful construction and expression of pcDNA3.1AB lay foundation for the advance research of gene expression and bigem DNA vaccine.