PiggyBac vectors in pluripotent stem cell research and applications

The piggyBac transposon is a mobile genetic element discovered about 40 years ago in baculoviruses infecting moth cells. It was later turned into a useful vector for gene delivery and stable integration in mammalian cells. Its fortune comes from some remarkable features, which include: the possibility to separate the transposase enzyme from the cis-elements required for transposition, its high transposition activity in mouse and human cells, the opportunity to deliver large cargoes and complex genetic cassettes, the possibility to engineer its components, lack of epigenetic silencing in stem cells, and, last but not least, the possibility to remove it from host cells leaving the genome unchanged. The field of pluripotent stem cells has particularly benefited from piggyBac-based systems, which have been used, among other applications, for reprogramming to pluripotency and for differentiation into several cell types of interest, including neurons, skeletal muscle, and hepatocytes. Lastly, piggyBac has been also used to increase the possibilities offered by genome editing tools. In this chapter we provide a review of the literature illustrating the possibilities offered by piggyBac to boost pluripotent stem cells research and applications.