Cheng Xin, Dunaway Stephen, Ivessa Andreas S
Department of Cell Biology and Molecular Medicine, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, 185 South Orange Avenue, Newark, NJ 07101-1709, USA.
Mitochondrion. 2007 May;7(3):211-22. doi: 10.1016/j.mito.2006.11.023. Epub 2006 Dec 9.
Mitochondrial DNA (mtDNA) is highly susceptible to oxidative and chemically induced damage, and these insults lead to a number of diseases. In Saccharomyces cerevisiae, the DNA helicase Pif1p is localized to the nucleus and mitochondria. We show that pif1 mutant cells are sensitive to ethidium bromide-induced damage and this mtDNA is prone to fragmentation. We also show that Pif1p associates with mtDNA. In pif1 mutant cells, mtDNA breaks at specific sites that exhibit Pif1-dependent recombination. We conclude that Pif1p participates in the protection from double-stranded (ds) DNA breaks or alternatively in the repair process of dsDNA breaks in mtDNA.
线粒体DNA（mtDNA）极易受到氧化和化学诱导损伤，这些损伤会导致多种疾病。在酿酒酵母中，DNA解旋酶Pif1p定位于细胞核和线粒体。我们发现，pif1突变细胞对溴化乙锭诱导的损伤敏感，且这种线粒体DNA易于断裂。我们还发现Pif1p与线粒体DNA相关联。在pif1突变细胞中，线粒体DNA在特定位点断裂，这些位点表现出Pif1依赖性重组。我们得出结论，Pif1p参与保护线粒体DNA免受双链（ds）DNA断裂，或者参与线粒体DNA中dsDNA断裂的修复过程。
