Reduction of plasmid vector backbone length enhances reporter gene expression.

Gene therapy has a wide range of applications for various types of pathologies. Viral methods of gene delivery provide high levels of gene expression but have various safety concerns. Non-viral methods are largely known to provide lower levels of expression. We aim to address this issue by using plasmid DNA with smaller backbones to increase gene expression levels when delivered using non-viral methods. In this study we compare gene expression levels between two vectors with firefly luciferase encoding gene insert using liposome complexes and gene electrotransfer as delivery methods. A 2-fold reduction in plasmid vector backbone size, disproportionately enhanced gene expression levels more than 10-fold in rat tenocytes in vitro, and rat myocardium in vivo, while improvements in delivery to the skin were more moderate.