TABLE 3.

Features of Liver-Directed Non-Viral Gene Therapy Methods

Method	Integration and persistence	In vivo gene transfer efficiency to liver	Liver-specificity	Immunological*, integration site and transgene size
NON-VIRAL VECTORS:
Sleeping Beauty Transposons	Permanent	High efficiency	Liver targeted	Probably non-immunogenic; preferentially inserts transgenes into TA dinucleotide sites in nontranscribed and intronic regions; ~10kB - efficiency decreases with transgene size
PiggyBac Transposons	Permanent	High efficiency	Liver targeted	Probably non-immunogenic; ability to integrate relatively large transgenes (up to 100-kb); TTAA target sequences
PhiC31 Integrase	Permanent	High efficiency	Liver targeted	Probably non-immunogenic; unlimited transgene size; integrates in mammalian genome at pseudo attP sites