Nuclear expression of a mitochondrial DNA gene: mitochondrial targeting of allotopically expressed mutant ATP6 in transgenic mice

J Biomed Biotechnol. 2012:2012:541245. doi: 10.1155/2012/541245. Epub 2012 Jun 20.

Abstract

Nuclear encoding of mitochondrial DNA transgenes followed by mitochondrial targeting of the expressed proteins (allotopic expression; AE) represents a potentially powerful strategy for creating animal models of mtDNA disease. Mice were created that allotopically express either a mutant (A6M) or wildtype (A6W) mt-Atp6 transgene. Compared to non-transgenic controls, A6M mice displayed neuromuscular and motor deficiencies (wire hang, pole, and balance beam analyses; P < 0.05), no locomotor differences (gait analysis; P < 0.05) and enhanced endurance in Rota-Rod evaluations (P < 0.05). A6W mice exhibited inferior muscle strength (wire hang test; P < 0.05), no difference in balance beam footsteps, accelerating Rota-Rod, pole test and gait analyses; (P < 0.05) and superior performance in balance beam time-to-cross and constant velocity Rota-Rod analyses (P < 0.05) in comparison to non-transgenic control mice. Mice of both transgenic lines did not differ from non-transgenic controls in a number of bioenergetic and biochemical tests including measurements of serum lactate and mitochondrial MnSOD protein levels, ATP synthesis rate, and oxygen consumption (P > 0.05). This study illustrates a mouse model capable of circumventing in vivo mitochondrial mutations. Moreover, it provides evidence supporting AE as a tool for mtDNA disease research with implications in development of DNA-based therapeutics.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cell Nucleus / genetics*
  • Cell Nucleus / metabolism
  • Cloning, Molecular
  • DNA, Mitochondrial / genetics*
  • Female
  • Gene Expression
  • Genes, Mitochondrial*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Mitochondrial Proton-Translocating ATPases / biosynthesis
  • Mitochondrial Proton-Translocating ATPases / genetics*
  • Mitochondrial Proton-Translocating ATPases / metabolism
  • Models, Genetic
  • Motor Skills
  • Mutation

Substances

  • DNA, Mitochondrial
  • Mitochondrial Proton-Translocating ATPases
  • mt-Atp6 protein, mouse