title: Mitochondrially targeted ZFNs for selective degradation of pathogenic mitochondrial genomes bearing large-scale deletions or point mutations.
abstract: We designed and engineered mitochondrially targeted obligate heterodimeric zinc finger nucleases (mtZFNs) for site-specific elimination of pathogenic human mitochondrial DNA (mtDNA). We used mtZFNs to target and cleave mtDNA harbouring the m.8993T>G point mutation associated with neuropathy, ataxia, retinitis pigmentosa (NARP) and the "common deletion" (CD), a 4977-bp repeat-flanked deletion associated with adult-onset chronic progressive external ophthalmoplegia and, less frequently, Kearns-Sayre and Pearson's marrow pancreas syndromes. Expression of mtZFNs led to a reduction in mutant mtDNA haplotype load, and subsequent repopulation of wild-type mtDNA restored mitochondrial respiratory function in a CD cybrid cell model. This study constitutes proof-of-principle that, through heteroplasmy manipulation, delivery of site-specific nuclease activity to mitochondria can alleviate a severe biochemical phenotype in primary mitochondrial disease arising from deleted mtDNA species.
authors.affiliation: Medical Research Council, Mitochondrial Biology Unit, Cambridge, UK.
authors.forename: Payam A
authors.initials: PA
authors.lastname: Gammage
authors.forename: Joanna
authors.initials: J
authors.lastname: Rorbach
authors.forename: Anna I
authors.initials: AI
authors.lastname: Vincent
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Rebar
authors.forename: Michal
authors.initials: M
authors.lastname: Minczuk
mesh_terms: D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism*; D003851:Deoxyribonucleases; D015316:Genetic Therapy; D054629:Genome, Mitochondrial; D006801:Humans; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics; D028361:Mitochondrial Diseases / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism / Q000628:therapy*; D017354:Point Mutation; D021381:Protein Transport; D017384:Sequence Deletion
chemical_list: D004272:DNA, Mitochondrial; D003851:Deoxyribonucleases