Platelet genomics beats the catch-22.

advantages such as a larger cargo load ( 14 kb, allowing the inclusion of more genes or larger regulatory elements), different insertion preferences, and the exclusive use of TTAA target sequence.2-4 For some applications, the PB transposition offers an additional advantage: the integrated transposon can be precisely excised by re-expression of PB transposase transiently as shown by several groups in diverse systems. Although the current PB system is inferior for HSPCs to the SB system using the superactive SB100X, I predict that the PB transposase will be improved significantly soon. Together, these transposon systems offer hopes to achieve virusfree, long-term gene transfer and expression in HSPCs and other cell types for various forms of gene therapy. Conflict-of-interest disclosure: The author declares no competing financial interests. ■