Retargeting transposon insertions by the adeno-associated virus Rep protein

摘要

The Sleeping Beauty {SB), piggyBac [PB) and To/2 transposons are promising instruments for genome engineering. Integration site profiling of SB, PB and To/2 in human cells showed that PB and Tol2 insertions were enriched in genes, whereas SB insertions were randomly distributed. We aimed to introduce a bias into the target site selection properties of the transposon systems by taking advantage of the locus-specific integration system of adeno-associated virus (AAV). The AAV Rep protein binds to Rep recognition sequences (RRSs) in the human genome, and mediates viral integration into nearby sites. A series of fusion constructs consisting of the N-terminal DNA-binding domain of Rep and the transposases or the N57 domain of SB were generated. A plasmid-based transposition assay showed that Rep/SB yielded a 15-fold enrichment of transposition at a particular site near a targeted RRS. Genome-wide insertion site analysis indicated that an approach based on interactions between the SB transposase and Rep/N57 enriched transgene insertions at RRSs. We also provide evidence of biased insertion of the PB and Tol2 transposons. This study provides a comparative insight into target site selection properties of transposons, as well as proof-of-principle for targeted chromosomal transposition by composite protein-protein and protein-DNA interactions.