Format

Send to

Choose Destination
EMBO Mol Med. 2018 Sep;10(9). pii: e8084. doi: 10.15252/emmm.201708084.

mitoTev-TALE: a monomeric DNA editing enzyme to reduce mutant mitochondrial DNA levels.

Author information

1
Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA.
2
Department of Biochemistry, Schulich School of Medicine and Dentistry University of Western Ontario, London, ON, Canada.
3
Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA cmoraes@med.miami.edu.

Abstract

Pathogenic mitochondrial DNA (mtDNA) mutations often co-exist with wild-type molecules (mtDNA heteroplasmy). Phenotypes manifest when the percentage of mutant mtDNA is high (70-90%). Previously, our laboratory showed that mitochondria-targeted transcription activator-like effector nucleases (mitoTALENs) can eliminate mutant mtDNA from heteroplasmic cells. However, mitoTALENs are dimeric and relatively large, making it difficult to package their coding genes into viral vectors, limiting their clinical application. The smaller monomeric GIY-YIG homing nuclease from T4 phage (I-TevI) provides a potential alternative. We tested whether molecular hybrids (mitoTev-TALEs) could specifically bind and cleave mtDNA of patient-derived cybrids harboring different levels of the m.8344A>G mtDNA point mutation, associated with myoclonic epilepsy with ragged-red fibers (MERRF). We tested two mitoTev-TALE designs, one of which robustly shifted the mtDNA ratio toward the wild type. When this mitoTev-TALE was tested in a clone with high levels of the MERRF mutation (91% mutant), the shift in heteroplasmy resulted in an improvement of oxidative phosphorylation function. mitoTev-TALE provides an effective architecture for mtDNA editing that could facilitate therapeutic delivery of mtDNA editing enzymes to affected tissues.

KEYWORDS:

I‐TevI; heteroplasmy; mitoTev‐TALE; mitochondrial DNA; monomeric

PMID:
30012581
PMCID:
PMC6127889
DOI:
10.15252/emmm.201708084
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center