Mutational consequences of dNTP pool imbalances in E. coli.
Mutational consequences of dNTP pool imbalances in E. coli.
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DOI：
10.1016/j.dnarep.2012.10.011
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发表时间：
2013-01-01
期刊：
影响因子：
3.8
通讯作者：
Mathews, Christopher K.
中科院分区：
文献类型：
--
作者：
Schaaper, Roel M.;Mathews, Christopher K.
DNA合成的准确性取决于聚合酶的准确性以及可用的5′-脱氧核苷-三磷酸DNA前体（dNTPs）的质量和浓度。已经在体外研究了dNTPs和错误率之间的关系，但在体内复制过程中，对这些相关性的了解有限。我们已经在细菌E.大肠杆菌中的突变特性。这些菌株，缺陷dCTP脱氨酶和核苷二磷酸激酶，分别，其特征在于两个干扰dNTP池和一个突变表型。以前已经研究过NDK菌株，但是由于关于其突变表型的来源存在争议，所以将其包括在本研究中。我们发现，dcd菌株的细胞内dCTP水平增加（4倍），dGTP水平降低（2倍），同时显示，使用一组lacZ回复标记在错配修复缺陷（mutL）背景下测量，G·C→T·A和A·T→T·A颠换的强烈增变效应（分别增强27倍和42倍）。相比之下，ndk菌株具有降低的dATP水平（4倍）和适度增加的dCTP水平（2倍），而其增变效应仅针对A·T→T·A颠换。这两种菌株还显示出利福平耐药突变体的差异突变性。总的来说，我们的分析揭示了两种菌株的dNTP池的改变和复制错误率之间的令人满意的相关性，也表明，一个最低限度的解释ndk突变不需要假设超出dNTP池的预测效果。
The accuracy of DNA synthesis depends on the accuracy of the polymerase as well as the quality and concentration(s) of the available 5′-deoxynucleoside-triphosphate DNA precursors (dNTPs). The relationships between dNTPs and error rates have been studied in vitro, but only limited insights exist into these correlations during in vivo replication. We have investigated this issue in the bacterium E. coli by analyzing the mutational properties of dcd and ndk strains. These strains, defective in dCTP deaminase and nucleoside diphosphate kinase, respectively, are characterized by both disturbances of dNTP pools and a mutator phenotype. ndk strains have been studied before, but were included in this study, as controversies exist regarding the source of its mutator phenotype. We show that dcd strains suffer from increased intracellular levels of dCTP (four-fold) and reduced levels of dGTP (two-fold), while displaying, as measured using a set of lacZ reversion markers in a mismatch-repair defective (mutL) background, a strong mutator effect for G·C→T·A and A·T→T·A transversions (27- and 42-fold enhancement, respectively). In contrast, ndk strains possess a lowered dATP level (four-fold) and modestly enhanced dCTP level (2-fold), while its mutator effect is specific for just the A·T→T·A transversions. The two strains also display differential mutability for rifampicin-resistant mutants. Overall, our analysis reveals for both strains a satisfactory correlation between dNTP pool alterations and the replication error rates, and also suggests that a minimal explanation for the ndk mutator does not require assumptions beyond the predicted effect of the dNTP pools.
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影响因子：
3.8
作者：
Garibyan, L;Huang, T;Miller, JH
通讯作者：
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影响因子：
3.2
作者：
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通讯作者：
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DOI：
10.1073/pnas.95.17.10020
发表时间：
1998-08-18
影响因子：
11.1
作者：
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通讯作者：
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影响因子：
14.9
作者：
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通讯作者：
Chabes A
影响因子：
3.8
作者：
Ahluwalia, Deepti;Bienstock, Rachelle J.;Schaaper, Roe M.
通讯作者：
Schaaper, Roe M.