Nucleotide pools dictate the identity and frequency of ribonucleotide incorporation in mitochondrial DNA
Nucleotide pools dictate the identity and frequency of ribonucleotide incorporation in mitochondrial DNA
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DOI：
10.1371/journal.pgen.1006628
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发表时间：
2017-02-01
期刊：
影响因子：
4.5
通讯作者：
Clausen, Anders R.
中科院分区：
文献类型：
--
作者：
Berglund, Anna-Karin;Navarrete, Clara;Clausen, Anders R.
先前的工作已经证明了核糖核苷酸在人类线粒体DNA（mtDNA）中的存在，在本研究中，我们使用全基因组方法来精确定位这些核苷酸的位置。我们发现核糖核苷酸均匀分布在线粒体DNA的重链和轻链之间。掺入的核糖核苷酸的相对水平反映了DNA聚合酶。在DNA合成过程中区别四种核糖核苷酸。观察到的模式也依赖于线粒体脱氧核糖核苷酸（dNTP）池和致病突变，改变这些池改变绝对和相对水平的掺入核糖核苷酸。我们的分析强烈表明DNA聚合酶。依赖性掺入是线粒体DNA中核糖核苷酸的主要来源，并反驳了人类细胞中线粒体核糖核苷酸切除修复途径的存在。此外，我们清楚地表明，当dNTP池是有限的，核糖核苷酸作为一个来源的积木，以维持DNA复制。在患者细胞中的嵌入的核糖核苷酸水平的增加与干扰的核苷酸池可能有助于影响mtDNA的稳定性和损害新一轮的mtDNA复制的致病机制。
Previous work has demonstrated the presence of ribonucleotides in human mitochondrial DNA (mtDNA) and in the present study we use a genome-wide approach to precisely map the location of these. We find that ribonucleotides are distributed evenly between the heavy- and light-strand of mtDNA. The relative levels of incorporated ribonucleotides reflect that DNA polymerase. discriminates the four ribonucleotides differentially during DNA synthesis. The observed pattern is also dependent on the mitochondrial deoxyribonucleotide (dNTP) pools and disease-causing mutations that change these pools alter both the absolute and relative levels of incorporated ribonucleotides. Our analyses strongly suggest that DNA polymerase.-dependent incorporation is the main source of ribonucleotides in mtDNA and argues against the existence of a mitochondrial ribonucleotide excision repair pathway in human cells. Furthermore, we clearly demonstrate that when dNTP pools are limiting, ribonucleotides serve as a source of building blocks to maintain DNA replication. Increased levels of embedded ribonucleotides in patient cells with disturbed nucleotide pools may contribute to a pathogenic mechanism that affects mtDNA stability and impair new rounds of mtDNA replication.