In vivo occupancy of mitochondrial single-stranded DNA binding protein supports the strand displacement mode of DNA replication.
In vivo occupancy of mitochondrial single-stranded DNA binding protein supports the strand displacement mode of DNA replication.
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DOI：
10.1371/journal.pgen.1004832
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发表时间：
2014-12
期刊：
影响因子：
4.5
通讯作者：
Falkenberg M
中科院分区：
文献类型：
--
作者：
Miralles Fusté J;Shi Y;Wanrooij S;Zhu X;Jemt E;Persson Ö;Sabouri N;Gustafsson CM;Falkenberg M
线粒体DNA（mtDNA）编码氧化磷酸化所需的蛋白质，影响基因组的突变与许多疾病以及哺乳动物的自然衰老过程有关。人类mtDNA是由一种不同于核复制体的分子机制复制的，但对mtDNA复制的确切模式仍然没有共识。我们在这里证明，线粒体单链DNA结合蛋白（mtSSB）指导mtDNA复制的起点特异性启动。MtSSB覆盖在mtDNA复制过程中被置换的亲本重链。MtSSB阻断置换链上的引物合成，并将轻链mtDNA合成的起始限制在轻链DNA合成的特定起点（OriL）。mtSSB的体内占有率曲线显示出不同的模式，最高水平的mtSSB接近线粒体控制区，并逐渐下降到OriL。该模式与预期的mtDNA合成链置换模式的复制产物相关，为线粒体DNA复制的这一有争议的模型提供了强有力的体内支持。线粒体是细胞质细胞器，其产生细胞用作化学能量来源的大部分三磷酸腺苷（ATP）。ATP产生所需的蛋白质子集由不同的线粒体DNA基因组（mtDNA）编码。线粒体DNA的适当维护是必不可少的，因为这种环状分子的突变或缺失可能导致许多不同的疾病，也有助于正常衰老。我们感兴趣的是确保mtDNA正确复制和繁殖的分子机制。即使许多负责的酶已经被确定，在我们的科学领域仍然存在关于mtDNA复制的确切模式的争论。我们在这里使用了体外生物化学和体内蛋白质-DNA相互作用表征的组合来解决这个问题。我们的研究结果表明，线粒体单链DNA结合蛋白（mtSSB）限制启动mtDNA复制到一个特定的复制起点。通过描述mtSSB如何在体内与mtDNA的两条链相互作用，我们能够直接证明一种线粒体DNA复制模式的相关性，同时严重质疑多年来提出的其他替代模式的有效性。
Mitochondrial DNA (mtDNA) encodes for proteins required for oxidative phosphorylation, and mutations affecting the genome have been linked to a number of diseases as well as the natural ageing process in mammals. Human mtDNA is replicated by a molecular machinery that is distinct from the nuclear replisome, but there is still no consensus on the exact mode of mtDNA replication. We here demonstrate that the mitochondrial single-stranded DNA binding protein (mtSSB) directs origin specific initiation of mtDNA replication. MtSSB covers the parental heavy strand, which is displaced during mtDNA replication. MtSSB blocks primer synthesis on the displaced strand and restricts initiation of light-strand mtDNA synthesis to the specific origin of light-strand DNA synthesis (OriL). The in vivo occupancy profile of mtSSB displays a distinct pattern, with the highest levels of mtSSB close to the mitochondrial control region and with a gradual decline towards OriL. The pattern correlates with the replication products expected for the strand displacement mode of mtDNA synthesis, lending strong in vivo support for this debated model for mitochondrial DNA replication. Mitochondria are cytoplasmatic organelles that produce most of the adenosine triphosphate (ATP) used by the cell as a source of chemical energy. A subset of proteins required for ATP production is encoded by a distinct mitochondrial DNA genome (mtDNA). Proper maintenance of mtDNA is essential, since mutations or depletion of this circular molecule may lead to a number of different diseases and also contribute to normal ageing. We are interested in the molecular mechanisms that ensure correct replication and propagation of mtDNA. Even if many of the responsible enzymes have been identified, there is still a debate within our scientific field regarding the exact mode of mtDNA replication. We have here used a combination of in vitro biochemistry and in vivo protein-DNA interaction characterization to address this question. Our findings demonstrate that the mitochondrial single-stranded DNA-binding protein (mtSSB) restricts initiation of mtDNA replication to a specific origin of replication. By characterizing how mtSSB interacts with the two strands of mtDNA in vivo, we are able to directly demonstrate the relevance of one proposed mode of mitochondrial DNA replication and at the same time seriously question the validity of other, alternative modes that have been proposed over the years.
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影响因子：
14.9
作者：
Rajala N;Gerhold JM;Martinsson P;Klymov A;Spelbrink JN
通讯作者：
Spelbrink JN
DOI：
10.1083/jcb.201010024
发表时间：
2011-05-30
期刊：
The Journal of cell biology
影响因子：
--
作者：
Park CB;Larsson NG
通讯作者：
Larsson NG
影响因子：
30.8
作者：
Spelbrink, JN;Li, FY;Larsson, C
通讯作者：
Larsson, C
DOI：
10.1073/pnas.69.12.3810
发表时间：
1972-01-01
影响因子：
11.1
作者：
ROBBERSO.DL;CLAYTON, DA
通讯作者：
CLAYTON, DA
影响因子：
16
作者：
Fuste, Javier Miralles;Wanrooij, Sjoerd;Falkenberg, Maria
通讯作者：
Falkenberg, Maria