A novel method to increase transgene expression and the stability of gene therapy-associated episomal vectors

Non-viral episomal vectors offer a safe and attractive alternative to viral and integrated vectors by avoiding insertional mutagenesis and position effects, making them ideal expression vectors for gene therapy [1].The first non-viral episomal vector, pEPI-1, which is based on the full-length scaffold/matrix attachment region (S/MAR), was established by Piechaczek et al. [2].The full-length S/MAR element interacts with the nuclear matrix via the matrix protein SAF-A, thereby maintaining mitotic stability and transgene expression [3,4].Several strategies, including optimization of