Aleksandra Trifunovic

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Point mutations and deletions of mitochondrial DNA (mtDNA) accumulate in a variety of tissues during ageing in humans, monkeys and rodents. These mutations are unevenly distributed and can accumulate clonally in certain cells, causing a mosaic pattern of respiratory chain deficiency in tissues such as heart, skeletal muscle and brain. In terms of the ageing(More)
Characterization of the basic transcription machinery of mammalian mitochondrial DNA (mtDNA) is of fundamental biological interest and may also lead to therapeutic interventions for human diseases associated with mitochondrial dysfunction. Here we report that mitochondrial transcription factors B1 (TFB1M) and B2 (TFB2M) are necessary for basal transcription(More)
Many muscular and neurological disorders are associated with mitochondrial dysfunction and are often accompanied by changes in mitochondrial morphology. Mutations in the gene encoding OPA1, a protein required for fusion of mitochondria, are associated with hereditary autosomal dominant optic atrophy type I. Here we show that mitochondrial fragmentation(More)
Mitochondrial dysfunction is implicated in the pathophysiology of Parkinson's disease (PD), a common age-associated neurodegenerative disease characterized by intraneuronal inclusions (Lewy bodies) and progressive degeneration of the nigrostriatal dopamine (DA) system. It has recently been demonstrated that midbrain DA neurons of PD patients and elderly(More)
Mitochondrial DNA (mtDNA) polymerase gamma (Polg) is a heterodimeric enzyme containing a Pol I-like catalytic core (PolgA) and an accessory subunit. Mutations in POLGA, affecting the stability of mtDNA, have been identified in several human pathologies such as progressive external ophthalmoplegia and Alpers' syndrome. Extensive literature shows(More)
There is an intense debate concerning whether selection or demographics has been most important in shaping the sequence variation observed in modern human mitochondrial DNA (mtDNA). Purifying selection is thought to be important in shaping mtDNA sequence evolution, but the strength of this selection has been debated, mainly due to the threshold effect of(More)
A number of studies showed that the development and the lifespan of Caenorhabditis elegans is dependent on mitochondrial function. In this study, we addressed the role of mitochondrial DNA levels and mtDNA maintenance in development of C. elegans by analyzing deletion mutants for mitochondrial polymerase gamma (polg-1(ok1548)). Surprisingly, even though(More)
The mitochondrial theory of aging proposes that reactive oxygen species (ROS) generated inside the cell will lead, with time, to increasing amounts of oxidative damage to various cell components. The main site for ROS production is the respiratory chain inside the mitochondria and accumulation of mtDNA mutations, and impaired respiratory chain function have(More)
The mtDNA mutator mice have high levels of point mutations and linear deletions of mtDNA causing a progressive respiratory chain dysfunction and a premature aging phenotype. We have now performed molecular analyses to determine the mechanism whereby these mtDNA mutations impair respiratory chain function. We report that mitochondrial protein synthesis is(More)
At present, there are few means to track symptomatic stages of CNS aging. Thus, although metabolic changes are implicated in mtDNA mutation-driven aging, the manifestations remain unclear. Here, we used normally aging and prematurely aging mtDNA mutator mice to establish a molecular link between mitochondrial dysfunction and abnormal metabolism in the aging(More)