Publications (2)12.31 Total impact
-
Article: Evolution meets disease: penetrance and functional epistasis of mitochondrial tRNA mutations.
[show abstract] [hide abstract]
ABSTRACT: About half of the mitochondrial DNA (mtDNA) mutations causing diseases in humans occur in tRNA genes. Particularly intriguing are those pathogenic tRNA mutations than can reach homoplasmy and yet show very different penetrance among patients. These mutations are scarce and, in addition to their obvious interest for understanding human pathology, they can be excellent experimental examples to model evolution and fixation of mitochondrial tRNA mutations. To date, the only source of this type of mutations is human patients. We report here the generation and characterization of the first mitochondrial tRNA pathological mutation in mouse cells, an m.3739G>A transition in the mitochondrial mt-Ti gene. This mutation recapitulates the molecular hallmarks of a disease-causing mutation described in humans, an m.4290T>C transition affecting also the human mt-Ti gene. We could determine that the pathogenic molecular mechanism, induced by both the mouse and the human mutations, is a high frequency of abnormal folding of the tRNA(Ile) that cannot be charged with isoleucine. We demonstrate that the cells harboring the mouse or human mutant tRNA have exacerbated mitochondrial biogenesis triggered by an increase in mitochondrial ROS production as a compensatory response. We propose that both the nature of the pathogenic mechanism combined with the existence of a compensatory mechanism can explain the penetrance pattern of this mutation. This particular behavior can allow a scenario for the evolution of mitochondrial tRNAs in which the fixation of two alleles that are individually deleterious can proceed in two steps and not require the simultaneous mutation of both.PLoS Genetics 04/2011; 7(4):e1001379. · 8.69 Impact Factor -
Article: Isolation of mitochondria for biogenetical studies: An update.
[show abstract] [hide abstract]
ABSTRACT: The use of good quality preparations of isolated mitochondria is necessary when studying the mitochondrial biogenetical activities. This article explains a fast and simple method for the purification of mammalian mitochondria from different tissues and cultured cells, that is suitable for the analysis of many aspects of the organelle's biogenesis. The mitochondria isolated following the protocol described here, are highly active and capable of DNA, RNA and protein synthesis. Mitochondrial tRNA aminoacylation, mtDNA-protein interactions and specific import of added proteins into the organelles, can also be studied using this kind of preparations.Mitochondrion 04/2010; 10(3):253-62. · 3.62 Impact Factor
