Comparison of <i>piggyBac</i>, <i>TcBuster</i>, and <i>Tol2</i> at varying transposase: transposon ratios.

<p>HEK-293 cells in 6-well plates were transfected in triplicate with the indicated amount of transposase helper plasmid (+) or pUC19 (−) and plasmids carrying the neomycin-resistance transposon for each system. The amount of transposon plasmid transfected was 200 ng (<b>a</b>), 500 ng (<b>b</b>), or 900 ng (<b>c</b>). In <b>c</b>, the <i>piggyBac</i> (+) transposase plates had approximately 1000 colonies, too many to count (TMTC). Cells were diluted 1∶750 onto 10 cm plates in media containing geneticin for selection and incubated for two weeks to allow drug-resistant cells to form colonies that were fixed, stained and counted. Error bars represent the SEM (n = 3).