Mortusewicz Oliver, Amé Jean-Christophe, Schreiber Valérie, Leonhardt Heinrich
Munich Center for Integrated Protein Science CiPS , Ludwig Maximilians University Munich, 82152 Planegg-Martinsried, Germany.
Nucleic Acids Res. 2007;35(22):7665-75. doi: 10.1093/nar/gkm933. Epub 2007 Nov 3.
Genome integrity is constantly threatened by DNA lesions arising from numerous exogenous and endogenous sources. Survival depends on immediate recognition of these lesions and rapid recruitment of repair factors. Using laser microirradiation and live cell microscopy we found that the DNA-damage dependent poly(ADP-ribose) polymerases (PARP) PARP-1 and PARP-2 are recruited to DNA damage sites, however, with different kinetics and roles. With specific PARP inhibitors and mutations, we could show that the initial recruitment of PARP-1 is mediated by the DNA-binding domain. PARP-1 activation and localized poly(ADP-ribose) synthesis then generates binding sites for a second wave of PARP-1 recruitment and for the rapid accumulation of the loading platform XRCC1 at repair sites. Further PARP-1 poly(ADP-ribosyl)ation eventually initiates the release of PARP-1. We conclude that feedback regulated recruitment of PARP-1 and concomitant local poly(ADP-ribosyl)ation at DNA lesions amplifies a signal for rapid recruitment of repair factors enabling efficient restoration of genome integrity.
基因组完整性不断受到来自众多外源性和内源性来源的DNA损伤的威胁。细胞存活依赖于对这些损伤的即时识别以及修复因子的快速募集。利用激光微照射和活细胞显微镜技术，我们发现DNA损伤依赖性聚（ADP - 核糖）聚合酶（PARP）PARP - 1和PARP - 2会被募集到DNA损伤位点，然而，其动力学和作用不同。通过使用特异性PARP抑制剂和突变，我们能够表明PARP - 1的初始募集是由DNA结合结构域介导的。PARP - 1的激活和局部聚（ADP - 核糖）合成随后为PARP - 1的第二轮募集以及加载平台XRCC1在修复位点的快速积累产生结合位点。进一步的PARP - 1聚（ADP - 核糖基）化最终引发PARP - 1的释放。我们得出结论，PARP - 1的反馈调节募集以及在DNA损伤处伴随的局部聚（ADP - 核糖基）化放大了一个信号，用于快速募集修复因子，从而实现基因组完整性的有效恢复。
