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Updated: Jun 8, 2026
Generation of Genomic Deletions in Mammalian Cell Lines via CRISPR/Cas9
Published on: January 3, 2015
Plasmid2MC: efficient cell-free generation of high-purity minicircle DNA for genome editing in mammalian cells
Roman Teo Oliynyk1,2, Ahmed Mahas3, Emil Karpinski3
1Department of Genetics, Harvard Medical School, Boston, MA, USA. roli573@aucklanduni.ac.nz.
Abstract:
DNA plasmids are widely used for delivering proteins and RNA in genome editing. However, their bacterial components can lead to inactivation, cell toxicity, and reduced efficiency compared to minicircle DNA (mcDNA), which lacks such bacterial sequences. Existing commercial kits that recombine plasmids into mcDNA within proprietary bacterial strains are labor-intensive, yield inconsistent results, and often produce endotoxin-contaminated low-quality mcDNA. To address this challenge, we developed Plasmid2MC, a novel cell-free method utilizing ΦC31 integrase-mediated recombination to efficiently excise the bacterial backbone from conventionally prepared plasmids, followed by digestion of the bacterial backbone and all other DNA contaminants, resulting in highly pure and virtually endotoxin-free mcDNA. We demonstrated the application of mcDNA to express CRISPR-dCas9 for base editing in HEK293T cells and mouse embryonic stem cells, as well as for homology-independent targeted insertion (HITI) genome editing. The method's ease of preparation, high efficiency, and the high purity of the resulting mcDNA make Plasmid2MC a valuable tool for applications requiring bacterial backbone-free circular DNA.
Insights
Plasmid2MC is a new cell-free method that creates high-purity minicircle DNA (mcDNA) from standard plasmids. This advanced DNA technology improves genome editing efficiency and reduces toxicity by removing bacterial components.
Area of Science:
- Molecular Biology
- Gene Editing Technologies
- Biotechnology
Background:
- DNA plasmids are common for gene delivery but contain bacterial components causing toxicity and reduced efficiency.
- Current methods for producing minicircle DNA (mcDNA) are inefficient, labor-intensive, and yield low-quality, endotoxin-contaminated products.
Purpose of the Study:
- To develop a novel, efficient, and cell-free method for producing high-purity mcDNA.
- To overcome the limitations of existing plasmid-to-mcDNA conversion kits.
Main Methods:
- Developed Plasmid2MC, a cell-free system using ΦC31 integrase-mediated recombination to excise bacterial backbones from plasmids.
- Utilized enzymatic digestion to remove residual bacterial DNA and contaminants, yielding pure mcDNA.
Main Results:
- Plasmid2MC efficiently produced virtually endotoxin-free mcDNA.
- Demonstrated successful application of mcDNA for CRISPR-dCas9 base editing and homology-independent targeted insertion (HITI) in mammalian cells.
Conclusions:
- Plasmid2MC offers a simple, highly efficient method for generating pure mcDNA.
- This technology is valuable for applications requiring bacterial backbone-free circular DNA, enhancing genome editing outcomes.
