An in vitro approach for production of non-scar minicircle DNA vectors

Minicircle (MC) DNA vectors have shown prolonged expression in gene transfection studies. Here we have developed a facile approach based on enzyme-catalyzed reactions to produce the MC DNA in vitro. eGFP plasmid was inserted by two mirror-symmetry pairs of EcoRV and HindIII restriction enzyme sites at both sides of the expression cassette. The highly purified eGFP MC DNA vector was obtained through a dephosphorylating/re-exposing process, followed by a selective ligation of MC DNA and selective removal of the bacterial backbone fragment. The GFP expression study showed a significant improvement by using MC vectors. This method mimics the recombination process in vitro, avoids the need for specific bacterial strains, strict inducing strategy and complex purification approach, which provides potential for manufacturing the high-quality minicircle DNA vectors for vaccination and gene therapy applications.