A number of nuclear mutations have been identified in a variety of mitochondrial diseases including progressive external ophthalmoplegia (PEO), Alpers syndrome, and other neuromuscular and oxidative phosphorylation defects. More than fifty mutations have been identified in POLG, which encodes the human mitochondrial DNA polymerase gamma, in PEO and Alpers patients. To rapidly characterize the effects of these mutations, we have developed a versatile system that enables the consequences of homologous mutations, introduced in situ into the yeast mitochondrial DNA polymerase gene MIP1, to be evaluated in vivo in haploid and diploid cells. Overall, distinct phenotypes for expression of each of the mip1-PEO mutations were observed, including respiration-defective cells with decreased viability, dominant-negative mutant polymerases, elevated levels of mitochondrial and nuclear DNA damage, and chromosomal mutations. Mutations in the polymerase domain caused the most severe phenotype accompanied by loss of mitochondrial DNA and cell viability, while the mutation in the exonuclease domain showed mild dominance with loss of mitochondrial DNA. Interestingly, the linker region mutation caused elevated mitochondrial and nuclear DNA damage. The cellular processes contributing to these observations in the mutant yeast cells are potentially relevant to understanding the pathologies observed in human mitochondrial disease patients.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Annotation Extension||Reference|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Assay||Construct||Conditions||Strain Background||Reference|