XLF acts as a flexible connector during non-homologous end joining.
XLF acts as a flexible connector during non-homologous end joining.
复制标题
XLF在非同源末端连接期间充当灵活的连接器。
DOI：
10.7554/elife.61920
复制
发表时间：
2020-12-08
期刊：
影响因子：
7.7
通讯作者：
Loparo JJ
中科院分区：
文献类型：
--
作者：
Carney SM;Moreno AT;Piatt SC;Cisneros-Aguirre M;Lopezcolorado FW;Stark JM;Loparo JJ
非同源末端连接（NHEJ）是脊椎动物中修复DNA双链断裂的主要途径。在NHEJ期间，DNA末端通过多蛋白质突触复合物保持在一起，直到它们被连接。在这里，我们使用非洲爪蟾卵提取物调查的XRCC 4样因子（XLF），在结束突触的一个关键因素的本质上无序的C-末端尾部的作用。我们证明，XLF尾沿着与Ku结合基序（KBM）在极端的C-末端所需的结束连接。虽然尾部的潜在序列可以变化，但NHEJ需要最小的尾部长度。实时观察末端突触的单分子FRET实验表明，这种缺陷是由于未能紧密对齐DNA末端。我们的数据支持一个模型，其中一个单一的C-末端尾栓XLF Ku，同时允许XLF形成与XRCC 4的相互作用，使突触复合物的形成。
Non-homologous end joining (NHEJ) is the predominant pathway that repairs DNA double-strand breaks in vertebrates. During NHEJ DNA ends are held together by a multi-protein synaptic complex until they are ligated. Here, we use Xenopus laevis egg extract to investigate the role of the intrinsically disordered C-terminal tail of the XRCC4-like factor (XLF), a critical factor in end synapsis. We demonstrate that the XLF tail along with the Ku-binding motif (KBM) at the extreme C-terminus are required for end joining. Although the underlying sequence of the tail can be varied, a minimal tail length is required for NHEJ. Single-molecule FRET experiments that observe end synapsis in real-time show that this defect is due to a failure to closely align DNA ends. Our data supports a model in which a single C-terminal tail tethers XLF to Ku, while allowing XLF to form interactions with XRCC4 that enable synaptic complex formation.