Mobilization of a 100 kb Genomic Cargo by the DNA Transposon piggyBac in Mouse Embryonic Stem Cells

Development of technologies that allow the stable delivery of large genomic DNA cargoes in mammalian systems is highly important for basic research as well as for applications in gene therapy. DNA transposons have emerged as flexible and efficient molecular vehicles to mediate stable cargo transfer. However, the ability to harbor DNA cargoes even up to 10 kb is limited with most of the of the known DNA transposons. Here we show that the DNA transposon piggyBac (PB) can transpose with human genomic DNA of up to 100 kb in mouse embryonic stem (ES) cells, making it to be the only known transposon to have such a large cargo capacity. The cargo integrity is maintained during the transposition and the copy number of the delivery can be controlled to one. Furthermore, cargoes up to 100 kb can also be removed from the genome by PB mediated excision without leaving any footprint at the genomic donor site. This development of piggyBac will facilitate a wider range of genetic and genomic applications. In conjunction with recent advances in the area of induced pluripotent stem (iPS) cells, the use of PB to mediate large genomic DNA delivery for therapeutic purposes will open up new possibilities to combat inherited diseases.