Ku recruits XLF to DNA double-strand breaks
Ku recruits XLF to DNA double-strand breaks
复制标题
DOI：
10.1038/sj.embor.7401137
复制
发表时间：
2008-01-01
期刊：
影响因子：
7.7
通讯作者：
Chen, David J.
中科院分区：
文献类型：
--
作者：
Yano, Ken-ichi;Morotomi-Yano, Keiko;Chen, David J.
XRCC4样因子（XLF）-也称为Cernunnos-最近已被证明参与非同源末端连接（NHEJ），这是哺乳动物细胞中DNA双链断裂（DSB）修复的主要途径。XLF可能通过刺激XRCC 4-连接酶IV介导的DSB连接来增强NHEJ。在这里，我们报告XLF招募DSB的机制细节。活细胞成像结合激光显微照射显示，XLF是DSB的早期反应者，Ku是XLF招募DSB的必要条件。生化分析表明，Ku-XLF相互作用发生在DNA上，Ku刺激XLF与DNA结合。出乎意料的是，XRCC4对于XLF向DSB的募集是不稳定的，尽管光漂白分析显示XRCC4稳定XLF与DSB的结合。我们的观察表明，XLF直接参与NHEJ机器的动态组装，并提供DSB识别的机制见解。
XRCC4-like factor (XLF)-also known as Cernunnos-has recently been shown to be involved in non-homologous end-joining (NHEJ), which is the main pathway for the repair of DNA double-strand breaks (DSBs) in mammalian cells. XLF is likely to enhance NHEJ by stimulating XRCC4-ligase IV-mediated joining of DSBs. Here, we report mechanistic details of XLF recruitment to DSBs. Live cell imaging combined with laser micro-irradiation showed that XLF is an early responder to DSBs and that Ku is essential for XLF recruitment to DSBs. Biochemical analysis showed that Ku-XLF interaction occurs on DNA and that Ku stimulates XLF binding to DNA. Unexpectedly, XRCC4 is dispensable for XLF recruitment to DSBs, although photo-bleaching analysis showed that XRCC4 stabilizes the binding of XLF to DSBs. Our observations showed the direct involvement of XLF in the dynamic assembly of the NHEJ machinery and provide mechanistic insights into DSB recognition.