A biochemically defined system for mammalian nonhomologous DNA end joining
A biochemically defined system for mammalian nonhomologous DNA end joining
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DOI：
10.1016/j.molcel.2004.11.017
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发表时间：
2004-12-03
期刊：
影响因子：
16
通讯作者：
Lieber, MR
中科院分区：
文献类型：
--
作者：
Ma, YM;Lu, HH;Lieber, MR
非同源末端连接（NHEJ）是多细胞真核生物修复双链DNA断裂（DSB）的主要途径。在这里，NHEJ反应已经通过使用纯化的Ku、DNA-PKCS、Artemis和XRCC 4：DNA连接酶IV蛋白质在体外重建，以连接不相容的末端以产生不同的接头。纯化的DNA聚合酶（pol）X家族成员（pol μ，pol λ和TdT，但不是pol β）有助于连接添加的方式是一致的，从基因敲除小鼠的相应数据。pol lambda和pol mu的贡献需要它们的BRCT结构域，并且在物理上和功能上都依赖于Ku。这表明Ku在NHEJ中在不相容的DNA末端具有特定的生化功能。XRCC 4：DNA连接酶IV复合物能够连接一条与反平行链仅具有最小碱基配对的链。连接的这一重要方面导致NHEJ步骤的迭代链加工模型。
Nonhomologous end joining (NHEJ) is a major pathway in multicellular eukaryotes for repairing double-strand DNA breaks (DSBs). Here, the NHEJ reactions have been reconstituted in vitro by using purified Ku, DNA-PKCS, Artemis, and XRCC4:DNA ligase IV proteins to join incompatible ends to yield diverse junctions. Purified DNA polymerase (pol) X family members (pol mu, pol lambda, and TdT, but not pol beta) contribute to junctional additions in ways that are consistent with corresponding data from genetic knockout mice. The pol lambda and pol mu contributions require their BRCT domains and are both physically and functionally dependent on Ku. This indicates a specific biochemical function for Ku in NHEJ at incompatible DNA ends. The XRCC4:DNA ligase IV complex is able to ligate one strand that has only minimal base pairing with the antiparallel strand. This important aspect of the ligation leads to an iterative strand-processing model for the steps of NHEJ.