p53 regulates mtDNA copy number and mitocheckpoint pathway.
p53 regulates mtDNA copy number and mitocheckpoint pathway.
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DOI：
10.4103/1477-3163.50893
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发表时间：
2009
影响因子：
--
通讯作者：
Singh KK
中科院分区：
文献类型：
--
作者：
Kulawiec M;Ayyasamy V;Singh KK
我们先前假设线粒体损伤检查点（mito-checkpoint）在维持细胞线粒体完整性中的作用。与这一假设一致，线粒体缺陷已被证明会导致核DNA的遗传和表观遗传变化、对细胞死亡的抵抗和肿瘤发生。在本文中，我们描述了线粒体氧化磷酸化（mtOXPHOS）的抑制引起的线粒体缺陷诱导细胞周期阻滞，类似于DNA损伤检查点反应的反应。用电子传递链抑制剂处理从p53野生型和p53缺陷型小鼠胚胎（p53 -/-）获得的原代小鼠胚胎成纤维细胞，进行细胞周期分析、ROS产生、线粒体含量分析和免疫印迹。采用真实的实时定量PCR检测p53 R2的表达。我们确定，虽然p53 +/+细胞在细胞周期中停滞，但p53 -/-细胞在暴露于线粒体抑制剂后继续分裂，表明p53在细胞周期的S期延迟中起重要作用。在mtOXPHOS抑制后，p53易位至线粒体。我们的研究还表明，p53依赖性诱导活性氧作为一个主要的信号触发线粒体检查点的反应。此外，我们的研究表明，p53的丢失导致p53 R2的下调，这有助于原代MEF细胞中mtDNA的耗尽。我们的研究表明，p53 1）作为线粒体检查点蛋白和2）调节线粒体DNA拷贝数和线粒体生物合成。我们描述了一个概念组织的线粒体检查点途径，其中确定的作用，p53在线粒体被纳入。
We previously hypothesized a role for mitochondria damage checkpoint (mito-checkpoint) in maintaining the mitochondrial integrity of cells. Consistent with this hypothesis, defects in mitochondria have been demonstrated to cause genetic and epigenetic changes in the nuclear DNA, resistance to cell-death and tumorigenesis. In this paper, we describe that defects in mitochondria arising from the inhibition of mitochondrial oxidative phosphorylation (mtOXPHOS) induce cell cycle arrest, a response similar to the DNA damage checkpoint response. Primary mouse embryonic fibroblasts obtained from p53 wild-type and p53-deficient mouse embryos (p53 -/-) were treated with inhibitors of electron transport chain and cell cycle analysis, ROS production, mitochondrial content analysis and immunoblotting was performed. The expression of p53R2 was also measured by real time quantitative PCR. We determined that, while p53 +/+ cells arrest in the cell cycle, p53 -/- cells continued to divide after exposure to mitochondrial inhibitors, showing that p53 plays an important role in the S-phase delay in the cell cycle. p53 is translocated to mitochondria after mtOXPHOS inhibition. Our study also revealed that p53-dependent induction of reactive oxygen species acts as a major signal triggering a mito-checkpoint response. Furthermore our study revealed that loss of p53 results in down regulation of p53R2 that contributes to depletion of mtDNA in primary MEF cells. Our study suggests that p53 1) functions as mito-checkpoint protein and 2) regulates mtDNA copy number and mitochondrial biogenesis. We describe a conceptual organization of the mito-checkpoint pathway in which identified roles of p53 in mitochondria are incorporated.