A role for MHR1, a gene required for mitochondrial genetic recombination, in the repair of damage spontaneously introduced in yeast mtDNA
AUTOR(ES)
Ling, Feng
FONTE
Oxford University Press
RESUMO
A nuclear recessive mutant in Saccharomyces cerevisiae, mhr1-1, is defective in mitochondrial genetic recombination at 30°C and shows extensive vegetative petite induction by UV irradiation at 30°C or when cultivated at a higher temperature (37°C). It has been postulated that mitochondrial DNA (mtDNA) is oxidatively damaged by by-products of oxidative respiration. Since genetic recombination plays a critical role in DNA repair in various organisms, we tested the possibility that MHR1 plays a role in the repair of oxidatively damaged mtDNA using an enzyme assay. mtDNA isolated from cells grown under standard (aerobic) conditions contained a much higher level of DNA lesions compared with mtDNA isolated from anaerobically grown cells. Soon after a temperature shift from 30 to 37°C the number of mtDNA lesions increased 2-fold in mhr1-1 mutant cells but not in MHR1 cells. Malonic acid, which decreased the oxidative stress in mitochondria, partially suppressed both petite induction and the temperature-induced increase in the amount of mtDNA damage in mhr1-1 cells at 37°C. Thus, functional mitochondria require active MHR1, which keeps the extent of spontaneous oxidative damage in mtDNA within a tolerable level. These observations are consistent with MHR1 having a possible role in mtDNA repair.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=115238Documentos Relacionados
- Recombination-dependent mtDNA partitioning: in vivo role of Mhr1p to promote pairing of homologous DNA
- MER1, a yeast gene required for chromosome pairing and genetic recombination, is induced in meiosis.
- Nitric oxide-induced damage to mtDNA and its subsequent repair.
- mtDNA recombination in a natural population
- Rearrangements of Human Mitochondrial DNA (mtDNA): New Insights into the Regulation of mtDNA Copy Number and Gene Expression