Break-induced replication is highly inaccurate.
Break-induced replication is highly inaccurate.
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DOI：
10.1371/journal.pbio.1000594
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发表时间：
2011-02-15
期刊：
影响因子：
9.8
通讯作者：
Malkova A
中科院分区：
文献类型：
--
作者：
Deem A;Keszthelyi A;Blackgrove T;Vayl A;Coffey B;Mathur R;Chabes A;Malkova A
在双链断裂处由单端同源重组启动的DNA复制是高度不准确的，因为它极大地刺激了复制叉整个路径上的移码突变。为了基因组复制和DNA修复，必须合成DNA。虽然前者是一个高度精确的过程，但与DNA损伤修复相关的短补丁合成往往容易出错。断裂诱导复制（BIR）是一种独特的细胞过程，它模仿正常DNA复制的速度、速率和复制数百个碱基的能力，但始于双链断裂（dsb）而不是复制起点。在这里，我们使用了一系列移码报告器来测量酿酒酵母中与BIR相关的突变。我们证明，在复制叉的整个路径上，BIR DNA合成本质上是不准确的，因为BIR期间的移码突变率高达正常复制期间的2800倍。重要的是，这种高诱变率不仅在BIR不太稳定的DSB附近观察到，而且在远离BIR复制叉快速稳定的DSB处也观察到。我们确定了聚合酶校对和错配修复可以纠正BIR错误。此外，dNTP水平在BIR期间升高，这导致了BIR相关的突变。我们认为，高水平的DNA聚合酶错误没有被错误纠正机制完全补偿，这在很大程度上导致了BIR期间的诱变，Pol δ产生了许多诱变错误。我们进一步假设，真核细胞中BIR的激活可能会显著促进突变的积累，从而促进癌症和进化。遗传信息的准确传递需要父母DNA的精确复制。突变（可能是有益的，也可能是有害的）产生于未被纠正的错误。DNA复制发生在细胞周期的s期，由于高度选择性的DNA聚合酶加上有效的错误纠正机制，DNA复制非常准确。相反，与短补丁DNA修复相关的DNA合成往往容易出错。断裂诱导复制（BIR）是发生在DNA修复过程中的一种有趣的大规模DNA复制。在这项研究中，我们采用了一种基于酵母的系统来研究与BIR相关的诱变水平，并将其与正常DNA复制过程中的诱变进行比较。我们报道了帧移，这是最有害的一种点突变，在BIR中比在正常的DNA复制中更频繁。令人惊讶的是，我们观察到大多数与BIR相关的突变是由负责正常DNA复制的聚合酶产生的，这被认为是高度精确的。总之，我们认为BIR是一种新的突变源，可能有助于疾病的发生和进化。
DNA replication initiated by one-ended homologous recombination at a double-strand break is highly inaccurate, as it greatly stimulates frameshift mutations over the entire path of the replication fork. DNA must be synthesized for purposes of genome duplication and DNA repair. While the former is a highly accurate process, short-patch synthesis associated with repair of DNA damage is often error-prone. Break-induced replication (BIR) is a unique cellular process that mimics normal DNA replication in its processivity, rate, and capacity to duplicate hundreds of kilobases, but is initiated at double-strand breaks (DSBs) rather than at replication origins. Here we employed a series of frameshift reporters to measure mutagenesis associated with BIR in Saccharomyces cerevisiae. We demonstrate that BIR DNA synthesis is intrinsically inaccurate over the entire path of the replication fork, as the rate of frameshift mutagenesis during BIR is up to 2,800-fold higher than during normal replication. Importantly, this high rate of mutagenesis was observed not only close to the DSB where BIR is less stable, but also far from the DSB where the BIR replication fork is fast and stabilized. We established that polymerase proofreading and mismatch repair correct BIR errors. Also, dNTP levels were elevated during BIR, and this contributed to BIR-related mutagenesis. We propose that a high level of DNA polymerase errors that is not fully compensated by error-correction mechanisms is largely responsible for mutagenesis during BIR, with Pol δ generating many of the mutagenic errors. We further postulate that activation of BIR in eukaryotic cells may significantly contribute to accumulation of mutations that fuel cancer and evolution. Accurate transmission of genetic information requires the precise replication of parental DNA. Mutations (which can be beneficial or deleterious) arise from errors that remain uncorrected. DNA replication occurs during S-phase of the cell cycle and is extremely accurate due to highly selective DNA polymerases coupled with effective error-correction mechanisms. In contrast, DNA synthesis associated with short-patch DNA repair is often error-prone. Break-induced replication (BIR) presents an interesting case of large-scale DNA duplication that occurs in the context of DNA repair. In this study we employed a yeast-based system to investigate the level of mutagenesis associated with BIR compared to mutagenesis during normal DNA replication. We report that frameshifts, which are the most deleterious kind of point mutation, are much more frequent during BIR than during normal DNA replication. Surprisingly, we observed that the majority of mutations associated with BIR were created by polymerases responsible for normal DNA replication, which are assumed to be highly precise. Overall, we propose that BIR is a novel source of mutagenesis that may contribute to disease genesis and evolution.
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影响因子：
4.5
作者：
Chung WH;Zhu Z;Papusha A;Malkova A;Ira G
通讯作者：
Ira G
DOI：
10.1084/jem.20020851
发表时间：
2002-08-19
期刊：
The Journal of experimental medicine
影响因子：
--
作者：
Difilippantonio MJ;Petersen S;Chen HT;Johnson R;Jasin M;Kanaar R;Ried T;Nussenzweig A
通讯作者：
Nussenzweig A
影响因子：
13.8
作者：
KOLODNER, RD
通讯作者：
KOLODNER, RD
DOI：
10.1126/science.1191125
发表时间：
2010-07-02
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Hicks WM;Kim M;Haber JE
通讯作者：
Haber JE
影响因子：
64.5
作者：
Chabes, A;Georgieva, B;Thelander, L
通讯作者：
Thelander, L