Nuclear expression of a mitochondrial DNA gene: mitochondrial targeting of allotopically expressed mutant ATP6 in transgenic mice.
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.
Department of Pathobiology, College of Veterinary Medicine, Auburn University, 212 Samford Hall, Auburn, AL 36849, USA.
David A
DA
Dunn
Carl A
CA
Pinkert
D000818:Animals; D002467:Cell Nucleus / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D050259:Genes, Mitochondrial; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D025261:Mitochondrial Proton-Translocating ATPases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D008957:Models, Genetic; D009048:Motor Skills; D009154:Mutation
D004272:DNA, Mitochondrial; D025261:Mitochondrial Proton-Translocating ATPases; C501006:mt-Atp6 protein, mouse