Figure 1.

Hyperactive piggyBac transposase is active in a human liver cell line. (a) The hepatoma cell line Huh-7 was co-transfected with piggyBac transposon carrying the GFP-puromycin resistance cassette under the control of the CMV promoter and either mPB or iPB7 piggyBac transposase plasmids (1:1 ratio). (b) Transposon and hyperactive transposase constructs were co-transfected in varying ratios (5:1, 2:1, 1:1, 1:2, 1:5 transposon:transposase) in Huh-7 cells. Control cultures were either mock-transfected or transfected with the transposon cassette only. Cells were selected for 3 weeks under puromycin pressure, fixed, stained with methylene blue, and colonies counted. n = 3 for each condition; bars indicate mean ± standard error. *indicates P < 0.05. CMV, cytomegalovirus.