Increased and imbalanced dNTP pools symmetrically promote both leading and lagging strand replication infidelity.
Increased and imbalanced dNTP pools symmetrically promote both leading and lagging strand replication infidelity.
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DOI：
10.1371/journal.pgen.1004846
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发表时间：
2014-12
期刊：
影响因子：
4.5
通讯作者：
Chabes A
中科院分区：
文献类型：
--
作者：
Buckland RJ;Watt DL;Chittoor B;Nilsson AK;Kunkel TA;Chabes A
DNA复制的保真度需要dNTPs的适当平衡，但核基因组的新生前导链和滞后链主要由亚基组成、蛋白质伙伴关系和生化特性（包括保真度）不同的复制酶合成。这些事实提出了一个问题，即不平衡的dNTP池是否会对前导链和滞后链复制保真度产生不同的影响。在这里，我们通过检测由酵母核糖核苷酸还原酶rnr1-Y285A突变驱动的链特异性复制不忠来验证这种可能性，该突变导致dTTP和dCTP浓度升高。CAN1突变报告基因在基因组中以相反的方向存在的结果表明，前导链和后导链合成的复制错误率，甚至令人惊讶的序列背景，都非常相似。此外，虽然许多由dNTP池失衡驱动的错配可以通过错配修复得到有效纠正，但其他错配修复的效率较低，特别是在序列上下文中，这表明由于高dTTP和dCTP浓度驱动的错配扩展增加而导致校对减少。因此，核基因组的两条DNA链由于这种dNTP池失衡而处于相似的突变风险中，即使两种主要的复制纠错机制在遗传上完好无损，这种风险也不会被完全抑制。DNA的组成部分dNTPs对生命至关重要，因此它们的产生在每个细胞内都受到严格控制。在某些情况下，如癌症、感染或药物，总体dNTP水平或dNTP平衡可能会发生变化。利用酵母遗传学技术，对单细胞面包酵母的dNTP池平衡进行了调控，分析了dNTP池平衡对DNA复制保真度的影响。我们还破坏了错配修复，这是一种内部安全系统，可以纠正复制错误，并在许多癌症中发生突变。通过对酵母细胞的DNA进行测序，我们可以深入了解导致基因组不稳定的突变形成机制。我们发现前导链和后链复制保真度同样受到dNTP池不平衡的影响，错配修复机制以高度可变的效率纠正由dNTP池不平衡驱动的复制错误。
The fidelity of DNA replication requires an appropriate balance of dNTPs, yet the nascent leading and lagging strands of the nuclear genome are primarily synthesized by replicases that differ in subunit composition, protein partnerships and biochemical properties, including fidelity. These facts pose the question of whether imbalanced dNTP pools differentially influence leading and lagging strand replication fidelity. Here we test this possibility by examining strand-specific replication infidelity driven by a mutation in yeast ribonucleotide reductase, rnr1-Y285A, that leads to elevated dTTP and dCTP concentrations. The results for the CAN1 mutational reporter gene present in opposite orientations in the genome reveal that the rates, and surprisingly even the sequence contexts, of replication errors are remarkably similar for leading and lagging strand synthesis. Moreover, while many mismatches driven by the dNTP pool imbalance are efficiently corrected by mismatch repair, others are repaired less efficiently, especially those in sequence contexts suggesting reduced proofreading due to increased mismatch extension driven by the high dTTP and dCTP concentrations. Thus the two DNA strands of the nuclear genome are at similar risk of mutations resulting from this dNTP pool imbalance, and this risk is not completely suppressed even when both major replication error correction mechanisms are genetically intact. The building blocks of DNA, dNTPs, are vital to life, and thus their production is carefully controlled within each cell. Under certain conditions, such as cancer, infection, or drugs, the overall dNTP level or dNTP balance can change. Using yeast genetics we manipulated the dNTP pool balance in unicellular baker's yeast and analysed the effects upon fidelity of DNA replication. We also disrupted mismatch repair, an internal safety system that corrects replication errors and is mutated in many cancers. By sequencing DNA from yeast cells with these alterations we gain insights into the mechanisms of mutation formation that contribute to genome instability. We find that the leading and lagging strand replication fidelity is affected similarly by the dNTP pool imbalance and that the mismatch repair machinery corrects replication errors driven by a dNTP pool imbalance with highly variable efficiencies.
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常见的与癌症相关的DNA聚合酶ε突变会导致异常强的突变器表型，表明富达缺陷与校对丧失不同。
影响因子：
11.2
作者：
Kane DP;Shcherbakova PV
通讯作者：
Shcherbakova PV
影响因子：
64.8
作者：
通讯作者：
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影响因子：
14.9
作者：
Kumar D;Viberg J;Nilsson AK;Chabes A
通讯作者：
Chabes A
DOI：
10.3109/10409238.2011.630372
发表时间：
2012-01
影响因子：
6.5
作者：
Hofer A;Crona M;Logan DT;Sjöberg BM
通讯作者：
Sjöberg BM
影响因子：
14.9
作者：
Kumar D;Abdulovic AL;Viberg J;Nilsson AK;Kunkel TA;Chabes A
通讯作者：
Chabes A