Objective  Appropriate cell line, expression vector, and transfection reagent were selected to enhance the transient expression of GFP recombinant protein for quick and efficient production of the proteins in CHO cells.

  Methods   Targeting GFP, various eukaryotic vectors were employed to carry the gene protein for transfection into ExpiCHO-S cells. Four days after transfection, number and intensity of expression fluorescence on the recombinant plasmids by different vectors were recorded. Four more days later, the cells were lysed, and the lysate supernatant harvested to verify the gene expressions by SDS-PAGE. Meanwhile, GFP recombinant plasmids in the supernatant were purified on a His Trap FF affinity chromatography column to quantify the protein expressions by western blot.

  Results  The recombinant plasmids, pCDNA3.1-GFP and pCDNA3.4-GFP had the expression fluorescence the greatest in number, pCIneo-GFP the highest on intensity, while pCMVHA the fewest in number and the lowest on intensity. SDS-PAGE and western blot showed the expressions of the first 3 recombinant plasmids were higher than those of pCHO-GFP or pCMVHA-GFP.

  Conclusion  The GFP recombinant plasmids constructed with the eukaryotic vectors, pCDNA3.1, pCDNA3.4, and pCIneo, exhibited the greatest expressions and were considered the choice vectors for future studies requiring transient expression.