Reactive oxygen species regulate DNA copy number in isolated yeast mitochondria by triggering recombination-mediated replication.
Reactive oxygen species regulate DNA copy number in isolated yeast mitochondria by triggering recombination-mediated replication.
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DOI：
10.1093/nar/gkn993
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发表时间：
2009-02
影响因子：
14.9
通讯作者：
Ling F
中科院分区：
文献类型：
--
作者：
Hori A;Yoshida M;Shibata T;Ling F
线粒体 DNA (mtDNA) 编码细胞 ATP 生成所必需的蛋白质。活性氧 (ROS) 是损害线粒体 DNA 和其他细胞成分的呼吸副产物。在酿酒酵母中，氧化碱基切除修复酶 Ntg1 在 mtDNA 复制起点 ori5 处引入双链断裂 (DSB)；该 DSB 启动由同源 DNA 配对蛋白 Mhr1 介导的滚环 mtDNA 复制。因此，ROS可能在mtDNA拷贝数的调节中发挥作用。在这里，我们证明用低浓度过氧化氢处理分离的线粒体以 Ntg1 和 Mhr1 依赖性方式增加 mtDNA 拷贝数。仅当 Ntg1 活跃时，这种治疗才会提高过度抑制 [rho-] mtDNA ori5 处的 DSB 水平。从过氧化氢处理的线粒体中提取的超抑制 [rho-] mtDNA 的体外 Ntg1 处理显示 ori5 位点的氧化修饰增加。我们还观察到纯化的 Ntg1 在含有氧化碱基的单链 DNA 中产生断裂，并且 ori5 基因座具有单链特征。此外，长期低水平的过氧化氢会增加体内线粒体DNA拷贝数。因此，我们提出ROS作为mtDNA拷贝数的调节剂，通过由Ntg1诱导的ori5单链区域中的DSB促进的Mhr1依赖性滚环复制启动来发挥作用。
Mitochondrial DNA (mtDNA) encodes proteins that are essential for cellular ATP production. Reactive oxygen species (ROS) are respiratory byproducts that damage mtDNA and other cellular components. In Saccharomyces cerevisiae, the oxidized base excision-repair enzyme Ntg1 introduces a double-stranded break (DSB) at the mtDNA replication origin ori5; this DSB initiates the rolling-circle mtDNA replication mediated by the homologous DNA pairing protein Mhr1. Thus, ROS may play a role in the regulation of mtDNA copy number. Here, we show that the treatment of isolated mitochondria with low concentrations of hydrogen peroxide increased mtDNA copy number in an Ntg1- and Mhr1-dependent manner. This treatment elevated the DSB levels at ori5 of hypersuppressive [rho–] mtDNA only if Ntg1 was active. In vitro Ntg1-treatment of hypersuppressive [rho–] mtDNA extracted from hydrogen peroxide-treated mitochondria revealed increased oxidative modifications at ori5 loci. We also observed that purified Ntg1 created breaks in single-stranded DNA harboring oxidized bases, and that ori5 loci have single-stranded character. Furthermore, chronic low levels of hydrogen peroxide increased in vivo mtDNA copy number. We therefore propose that ROS act as a regulator of mtDNA copy number, acting through the Mhr1-dependent initiation of rolling-circle replication promoted by Ntg1-induced DSB in the single-stranded regions at ori5.
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影响因子：
11.4
作者：
LING, F;MAKISHIMA, F;SHIBATA, T
通讯作者：
SHIBATA, T
影响因子：
64.8
作者：
SOUTHERN, EM
通讯作者：
SOUTHERN, EM
影响因子：
4.8
作者：
Dou, H;Mitra, S;Hazra, TK
通讯作者：
Hazra, TK
影响因子：
30.8
作者：
Moreno-Loshuertos, Raquel;Acin-Perez, Rebeca;Enriquez, Jose Antonio
通讯作者：
Enriquez, Jose Antonio
DOI：
10.1073/pnas.93.20.10735
发表时间：
1996-10-01
影响因子：
11.1
作者：
Eide, L;Bjoras, M;Seeberg, E
通讯作者：
Seeberg, E