Plasmids for Gene Therapy
Karthikeyan Kandavelou and Srinivasan Chandrasegaran
from: Plasmids: Current Research and Future Trends (Edited by: Georg Lipps). Caister Academic Press, U.K. (2008)
The success of gene therapy depends on the efficient insertion of therapeutic genes at the appropriate chromosomal target sites within the human genome, without causing cell injury, oncogenic mutations or an immune response. Although viral vectors offer excellent vehicles for highly efficient transduction of human cells, the associated safety concerns make non-viral delivery of therapeutic genes by using plasmid DNA into cells more attractive. The construction of plasmid vectors is simple and straightforward. Custom-designed zinc finger nucleases (ZFNs) that combine the non-specific cleavage domain (N) of FokI endonuclease with zinc finger proteins (ZFPs) offer a general way to deliver a site-specific double strand break (DSB) to the genome, and stimulate local homologous recombination (HR) by several orders of magnitude. This makes targeted gene correction or genome editing a viable option in human cells. Since ZFN-encoded plasmids could be used to transiently express ZFNs to target a DSB to a specific gene locus in human cells, they offer an excellent way for targeted delivery of the therapeutic genes to a pre-selected chromosomal site. The ZFN-encoded plasmid-based approach has the potential to circumvent all the problems associated with the viral delivery of therapeutic genes read more ...