Modulating mtDNA heteroplasmy by mitochondria-targeted restriction endonucleases in a 'differential multiple cleavage-site' model

Gene Ther. 2007 Sep;14(18):1309-18. doi: 10.1038/ Epub 2007 Jun 28.


The ability to manipulate mitochondrial DNA (mtDNA) heteroplasmy would provide a powerful tool to treat mitochondrial diseases. Recent studies showed that mitochondria-targeted restriction endonucleases can modify mtDNA heteroplasmy in a predictable and efficient manner if it recognizes a single site in the mutant mtDNA. However, the applicability of such model is limited to mutations that create a novel cleavage site, not present in the wild-type mtDNA. We attempted to extend this approach to a 'differential multiple cleavage site' model, where an mtDNA mutation creates an extra restriction site to the ones normally present in the wild-type mtDNA. Taking advantage of a heteroplasmic mouse model harboring two haplotypes of mtDNA (NZB/BALB) and using adenovirus as a gene vector, we delivered a mitochondria-targeted Scal restriction endonuclease to different mouse tissues. Scal recognizes five sites in the NZB mtDNA but only three in BALB mtDNA. Our results showed that changes in mtDNA heteroplasmy were obtained by the expression of mitochondria-targeted ScaI in both liver, after intravenous injection, and in skeletal muscle, after intramuscular injection. Although mtDNA depletion was an undesirable side effect, our data suggest that under a regulated expression system, mtDNA depletion could be minimized and restriction endonucleases recognizing multiple sites could have a potential for therapeutic use.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenoviridae / genetics
  • Animals
  • Ataxin-1
  • Ataxins
  • Chimera
  • DNA Cleavage
  • DNA Restriction Enzymes / genetics*
  • DNA Restriction Enzymes / metabolism
  • DNA, Mitochondrial / genetics*
  • Female
  • Gene Deletion
  • Gene Expression
  • Genetic Engineering
  • Genetic Therapy / methods*
  • Genetic Vectors / administration & dosage
  • Genetic Vectors / genetics
  • Haplotypes
  • Heterozygote
  • Immunoblotting
  • Immunohistochemistry
  • Injections, Intramuscular
  • Injections, Intravenous
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred NZB
  • Mitochondria, Liver / metabolism*
  • Mitochondria, Muscle / metabolism
  • Mitochondrial Diseases / genetics
  • Mitochondrial Diseases / therapy
  • Models, Genetic*
  • Nerve Tissue Proteins / genetics
  • Nuclear Proteins / genetics
  • Polymorphism, Restriction Fragment Length


  • Ataxin-1
  • Ataxins
  • Atxn1 protein, mouse
  • DNA, Mitochondrial
  • Nerve Tissue Proteins
  • Nuclear Proteins
  • DNA Restriction Enzymes