ARCUS endonucleases developed by Precisions BioSciences (Durham, United States) are, unlike ZNF or TALENS nucleases, unique protein components, which means they can be integrated into AAV9. The mitoARCUS endonuclease has been specifically developed to eliminate the m.3243A>G mitochondrial DNA mutations responsible for more than 80% of MELAS syndromes.
When tested on a cell line and on a tumour transplanted into a mouse, the mitoARCUS endonuclease proved effective in reversing heteroplasmy in favour of normal mitochondrial DNA and improving mitochondrial function, without off-target nuclear modification.
