Mgm101p is a novel component of the mitochondrial nucleoid that binds DNA and is required for the repair of oxidatively damaged mitochondrial DNA
Mgm101p is a novel component of the mitochondrial nucleoid that binds DNA and is required for the repair of oxidatively damaged mitochondrial DNA
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DOI：
10.1083/jcb.145.2.291
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发表时间：
1999-04-19
影响因子：
7.8
通讯作者：
Nunnari, J
中科院分区：
文献类型：
--
作者：
Meeusen, S;Tieu, QT;Nunnari, J
线粒体DNA（mtDNA）在细胞分裂期间的维持是后代具有呼吸能力所必需的。维持涉及线粒体类核的复制、修复、组装、分离和分配。MGM101基因是塞evevevisiae中线粒体DNA维持所必需的基因，但其作用尚不清楚。使用液相色谱串联质谱法，我们确定Mgm101p作为高度富集的类核的一个组成部分，这表明它发挥了类核特定的作用，在维护。亚细胞分级分离、间接免疫荧光和GFP标记显示Mgm101 p仅与细胞中的线粒体类核结构相关。此外，类核提取物的DNA亲和层析表明Mgm101p与DNA结合，表明其类核定位部分是由于这种活性。对含有温度敏感的mgm101等位基因的细胞的表型分析表明，Mgm101 p不参与mtDNA包装、分离、分配或进行中的mtDNA复制。我们研究了Mgm101p在mtDNA修复中的作用。与野生型细胞相比，mgm101细胞对紫外线照射引起的mtDNA损伤更敏感，对γ射线和H2O2处理引起的mtDNA损伤更敏感。因此，我们建议，Mgm101p执行一个重要的功能，在修复氧化损伤的线粒体DNA的线粒体基因组的维护所需的。
Maintenance of mitochondrial DNA (mtDNA) during cell division is required for progeny to be respiratory competent. Maintenance involves the replication, repair, assembly, segregation, and partitioning of the mitochondrial nucleoid. MGM101 has been identified as a gene essential for mtDNA maintenance in S, cevevisiae, but its role is unknown. Using liquid chromatography coupled with tandem mass spectrometry, we identified Mgm101p as a component of highly enriched nucleoids, suggesting that it plays a nucleoid-specific role in maintenance. Subcellular fractionation, indirect immunofluorescence and GFP tagging show that Mgm101p is exclusively associated with the mitochondrial nucleoid structure in cells. Furthermore, DNA affinity chromatography of nucleoid extracts indicates that Mgm101p binds to DNA, suggesting that its nucleoid localization is in part due to this activity. Phenotypic analysis of cells containing a temperature sensitive mgm101 allele suggests that Mgm101p is not involved in mtDNA packaging, segregation, partitioning or required for ongoing mtDNA replication. We examined Mgm101p's role in mtDNA repair. As compared with wild-type cells, mgm101 cells were more sensitive to mtDNA damage induced by UV irradiation and were hypersensitive to mtDNA damage induced by gamma rays and H2O2 treatment. Thus, we propose that Mgm101p performs an essential function in the repair of oxidatively damaged mtDNA that is required for the maintenance of the mitochondrial genome.