Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, USA.
Mitochondrion. 2018 Sep;42:23-32. doi: 10.1016/j.mito.2017.10.005. Epub 2017 Oct 12.
Mitochondrial DNA (mtDNA) double-strand break (DSB) repair is essential for maintaining mtDNA integrity, but little is known about the proteins involved in mtDNA DSB repair. Here, we utilize Saccharomyces cerevisiae as a eukaryotic model to identify proteins involved in mtDNA DSB repair. We show that Mhr1, a protein known to possess homologous DNA pairing activity in vitro, binds to mtDNA DSBs in vivo, indicating its involvement in mtDNA DSB repair. Our data also indicate that Yku80, a protein previously implicated in mtDNA DSB repair, does not compete with Mhr1 for binding to mtDNA DSBs. In fact, C-terminally tagged Yku80 could not be detected in yeast mitochondrial extracts. Therefore, we conclude that Mhr1, but not Yku80, is a potential mtDNA DSB repair factor in yeast.
线粒体 DNA（mtDNA）双链断裂（DSB）修复对于维持 mtDNA 完整性至关重要，但对于参与 mtDNA DSB 修复的蛋白质知之甚少。在这里，我们利用酿酒酵母作为真核模型来鉴定参与 mtDNA DSB 修复的蛋白质。我们表明，Mhr1 是一种已知在体外具有同源 DNA 配对活性的蛋白质，它在体内与 mtDNA DSB 结合，表明它参与 mtDNA DSB 修复。我们的数据还表明，先前涉及 mtDNA DSB 修复的 Yku80 蛋白不与 Mhr1 竞争与 mtDNA DSB 的结合。事实上，C 端标记的 Yku80 不能在酵母线粒体提取物中检测到。因此，我们得出结论，Mhr1 而不是 Yku80 是酵母中潜在的 mtDNA DSB 修复因子。
