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

Production of Minicircle DNA Vectors Using Site-Specific Recombinases

Minicircle DNA vectors are plasmid derivatives free of bacterial elements. These vectors are mostly provided from common plasmids via recombination by site-specific recombinases in E. coli. Absence of bacterial backbone in minicircle vectors results in high-level and persistent expression of transgene in comparison with conventional plasmids and provides promising vehicles for gene therapy and vaccination. Here we describe the production of replicative minicircle DNA vectors using the PBAD/araC system expressing ΦC31 integrase in E. coli.

A new version of targeted minicircle producer system for EBV-positive human nasopharyngeal carcinoma

Targeted gene therapy needs to be implemented for future therapies to ensure efficient activity at the site of patient primary tumors or metastases without causing intolerable side-effects. One of the elements of gene therapy is vector, which includes viral and non-viral vector. In the present study, we constructed a novel non-viral targeted gene therapeutic system by using the new minicircle (MC) producing plasmid for Epstein-Barr virus (EBV)-positive nasopharyngeal carcinoma (NPC). Molecular cloning technique was used to construct plasmids and electrophoretic analysis. Dual-luciferase reporter assay was used to evaluate the expression of luciferase. Fluorescence microscope was used to detect the expression of enhanced green fluorescence protein (EGFP). We constructed a new MC producing system pMC.BESPX-origin of plasmid replication (oriP), and demonstrated that this system could produce highly purified MC-oriP. Furthermore, our results showed that MC-oriP vector produced by the new system could mediate targeted luciferase gene expression in EBV-positive NPC cells. In addition, we verified that MC could mediate enhanced transgene expression compared with parent plasmid through EGFP transfection. The present study constructed a targeted expression vector pMC.BESPX-oriP which could carry diversified therapeutic genes for EBV-positive NPC and provides a new approach for MC-based therapies.