A Mechanism to Minimize Errors during Non-homologous End Joining.
A Mechanism to Minimize Errors during Non-homologous End Joining.
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DOI：
10.1016/j.molcel.2019.11.018
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发表时间：
2019-12
期刊：
影响因子：
16
通讯作者：
B. M. Stinson;A. Moreno;J. Walter;J. Loparo
中科院分区：
文献类型：
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作者：
B. M. Stinson;A. Moreno;J. Walter;J. Loparo
DNA的酶处理是所有DNA修复的基础，但必须避免不适当的DNA处理。在脊椎动物中，双链断裂主要通过非同源末端连接(NHEJ)修复，NHEJ直接连接DNA末端。NHEJ具有高度诱变性的潜力，因为它使用DNA聚合酶、核酸酶和其他酶来修改不相容的DNA末端，以允许它们连接。使用概括NHEJ的蛙卵提取物，我们证明末端处理需要形成一个“短程突触复合体”，在该复合体中，DNA末端在连接能力状态下紧密排列。此外，单分子成像直接证明了处理发生在短程复合体内。这种将末端处理限制在连接能力强的复合体上的做法，确保了DNA末端一旦相容就进行连接，从而将突变降至最低。我们的结果说明了酶催化与底物的高阶结构组织的协调如何最大化DNA修复的保真度。
Enzymatic processing of DNA underlies all DNA repair, yet inappropriate DNA processing must be avoided. In vertebrates, double-strand breaks are repaired predominantly by non-homologous end joining (NHEJ), which directly ligates DNA ends. NHEJ has the potential to be highly mutagenic because it uses DNA polymerases, nucleases, and other enzymes that modify incompatible DNA ends to allow their ligation. Using frog egg extracts that recapitulate NHEJ, we show that end processing requires the formation of a "short-range synaptic complex" in which DNA ends are closely aligned in a ligation-competent state. Furthermore, single-molecule imaging directly demonstrates that processing occurs within the short-range complex. This confinement of end processing to a ligation-competent complex ensures that DNA ends undergo ligation as soon as they become compatible, thereby minimizing mutagenesis. Our results illustrate how the coordination of enzymatic catalysis with higher-order structural organization of substrate maximizes the fidelity of DNA repair.