[The improvement and application of piggyBac transposon system in mammals]

The piggyBac (PB) transposon system is a useful genomic engineering tool due to its high transposition efficiency, precise excision, semi-random insertion and large cargo capacity. But, it still needs to further improve the transgenic efficiency and reduce the risk of endogenous disruption caused by the random insertion of exogenous gene, especially in transgenic experiments of individual mammals. In recent studies, the PB transposase is fused with a DNA binding protein as a chimeric protein, which can guide the transposon to pre-designed loci. Besides, PB transposases obtained by mutagenesis have dramatically enhanced transposition activity and generated a novel function which is excision competent and integration defective. Furthermore, PB transposon system can carry large exogenous DNA fragments up to 207 kb when combining with the bacterial artificial chromosome vector. So far, these modified transposon systems have been widely applied in genome studies, gene therapy and induced pluripotent stem cells (iPS cells). In this study, we review the latest studies on piggyBac transposon system and its application prospect.