Enzymatic tools for mitochondrial genome manipulation

Mutations in mitochondrial DNA (mtDNA) can manifest phenotypically as a wide range of neuromuscular and neurodegenerative pathologies that are currently only managed symptomatically without addressing the root cause. A promising approach is the development of molecular tools aimed at mtDNA cutting or editing. Unlike nuclear DNA, a cell can have hundreds or even thousands of mitochondrial genomes, and mutations can be present either in all of them or only in a subset. Consequently, the developed tools are aimed at reducing the number of copies of mutant mtDNA or editing mutant nucleotides. Despite some progress in the field of mitochondrial genome editing in human cells, working with model animals is still limited due to the complexity of their creation. Furthermore, not all existing editing systems can be easily adapted to function within mitochondria. In this review, we evaluate the mtDNA editing tools available today, with a particular focus on specific mtDNA mutations linked to hereditary mitochondrial diseases, aiming to provide an in-depth understanding of both the opportunities and hurdles to the development of mitochondrial genome editing technologies.