Figure 4.

Hyperactive piggyBac transposase mutants in mammalian Cells. (A) Relative activities of 15 hyperactive mutants in Chinese hamster ovarian carcinoma (CHO) cells. The transposon plasmid pSAD-EGFP containing EGFP in transposon and the transposase plasmid pLoxP-optimized hyPBase or pLoxP -mutant containing transposase were coelectrotransformed into CHO cells. After 7 days of culture, the cells that expressed green fluorescent protein were counted by flow cytometry. (B) Relative activities of WT PBase, hyPBase, optimized hyPBase, and bz-hyPBase. The upper and the lower row are two repeated results. The control cells containing plasmid pSAD-EGFP only showed almost no green fluorescent protein expression. The X-axis represented the intensity of EGFP, and the Y-axis represented the number of cells. The values represented the percent of EGFP cells in each sample.