Genetic mosaic analysis of a deleterious mitochondrial DNA mutation in Drosophila reveals novel aspects of mitochondrial regulation and function.
Bottom Line: In the present study, we found that the decrease in cytochrome c oxidase (COX) activity was ascribable to a temperature-dependent destabilization of cytochrome a heme.Using a genetic scheme that expresses a mitochondrially targeted restriction enzyme to induce tissue-specific homoplasmy in heteroplasmic flies, we found that mt:CoI(T300I) homoplasmy in the eye caused severe neurodegeneration at 29°C.Our results demonstrate a novel approach for Drosophila mtDNA genetics and its application in modeling mtDNA diseases.
Affiliation: Laboratory of Molecular Genetics, National Institutes of Health, Bethesda, MD 20892.Show MeSH
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Mentions: To understand the biochemical basis of the temperature sensitivity of mt:CoIT300I, we assayed the composition and activity of the respiratory chain complexes of mutant flies at both 25 and 29°C. Although CoI protein levels were comparable in mt:CoIT300I and wt flies (Figure 1A), cytochrome c oxidase (COX) activity in the mutant was decreased to ∼30% of wt activity at 25°C (Supplemental Figure S1A). The mutant COX appears unstable at restrictive condition, as the COX activity of mt:CoIT300I extract quickly diminished to <5% of wild type after incubating at 29°C for 40 min (Hill, Chen, et al., 2014).
Affiliation: Laboratory of Molecular Genetics, National Institutes of Health, Bethesda, MD 20892.