Meganucleases and Their Biomedical Applications

Abstract

Homing endonucleases and zinc‐finger nucleases are double‐stranded meganucleases that target large deoxyribonucleic acid (DNA) recognition sites, a feature that means only a few such sites are likely to be present in a mammalian‐sized genome. Several homing endonucleases have been used as templates to engineer tools that cleave DNA sequences other than their original wild‐type targets. Indeed, zinc‐finger nucleases have been designed to recognise specific genes. These custom meganucleases can be used to stimulate double‐strand break homologous recombination in cells, thereby inducing the repair of defective genes with very low toxicity levels. The use of tailored meganucleases opens up new possibilities for gene therapy in patients with monogenic diseases that can be treated ex vivo . This review provides an overview of recent advances in this field. Key Concepts: Meganucleases are double‐stranded DNAses that target large recognition sites. Meganucleases promote efficient gene targeting through double‐strand‐break‐induced homologous recombination. Homologous recombination and nonhomologous end joining are the two pathways that can be used to repair DNA double‐strand breaks. Meganucleases encompass homing endonucleases and zinc‐finger nucleases. Meganucleases are ideal scaffolds to engineer enzymes that accurately cleave DNA and induce recombination. Meganucleases can recognise unique sites of cleavage within a genome, permitting their use for therapeutic purposes in human diseases. X‐ray diffraction of crystallised proteins allows us to understand the relationship between the structure and function of biomolecules.

Meganuclease-Based Artificial Transcription Factors

“…This indicates that it may be possible to generate several dozen unique DIMN-based transcription factors. In addition, several hundred meganucleases without known recognition sequences were also identified . Moreover, a recent study showed that it is possible to fuse or redesign meganucleases − allowing the engineering of specific sequence recognition domains.…”

“…In addition, several hundred meganucleases without known recognition sequences were also identified. 34 Moreover, a recent study showed that it is possible to fuse or redesign meganucleases 35−37 allowing the engineering of specific sequence recognition domains. This concept was proven in a study aimed at producing a stable reduction in circulating PCSK9 and serum cholesterol levels by targeted gene disruption using an engineered meganuclease.…”

Comparison of the Feasibility, Efficiency, and Safety of Genome Editing Technologies

“…HEs occur in nature across the mitochondrial and chloroplast genomes of eukaryotes (particularly plants, algae, fungi, and protozoans) and in the genomes of archaea, bacteria, and bacteriophages [ 6 , 7 ]. Meanwhile, synthetic meganucleases are produced by swapping or modifying domains from different HEs [ 8 , 9 ].…”

Recent advances in genetic manipulation of crops: A promising approach to address the global food and industrial applications

“…They are double stranded DNases also called as homing nucleases that aim broad recognition sites, which stimulates effective gene targeting by double stranded break induced homologous recombination, leads to reform breaks in the DNA double strands. The engineered meganucleases adopted from microorganisms are altered to create double stranded breaks, which acts as a standard platform to direct the enzymes and exactly allow them to cleave the DNA at target site in the process of recombination (37). They are utilized to produce herbicide resistance and insect tolerance in cotton (38) and male sterility in maize (39).…”