Bartocci Cristina, Diedrich Jolene K, Ouzounov Iliana, Li Julia, Piunti Andrea, Pasini Diego, Yates John R, Lazzerini Denchi Eros
Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Cell Rep. 2014 May 22;7(4):1320-32. doi: 10.1016/j.celrep.2014.04.002. Epub 2014 May 9.
When telomeres become critically short, DNA damage response factors are recruited at chromosome ends, initiating a cellular response to DNA damage. We performed proteomic isolation of chromatin fragments (PICh) in order to define changes in chromatin composition that occur upon onset of acute telomere dysfunction triggered by depletion of the telomere-associated factor TRF2. This unbiased purification of telomere-associated proteins in functional or dysfunctional conditions revealed the dynamic changes in chromatin composition that take place at telomeres upon DNA damage induction. On the basis of our results, we describe a critical role for the polycomb group protein Ring1b in nonhomologous end-joining (NHEJ)-mediated end-to-end chromosome fusions. We show that cells with reduced levels of Ring1b have a reduced ability to repair uncapped telomeric chromatin. Our data represent an unbiased isolation of chromatin undergoing DNA damage and are a valuable resource to map the changes in chromatin composition in response to DNA damage activation.
当端粒变得极短时，DNA损伤反应因子会被招募到染色体末端，引发细胞对DNA损伤的反应。我们进行了染色质片段的蛋白质组学分离（PICh），以确定因端粒相关因子TRF2缺失引发的急性端粒功能障碍开始时染色质组成的变化。这种在功能或功能失调条件下对端粒相关蛋白的无偏纯化揭示了DNA损伤诱导后端粒处染色质组成的动态变化。基于我们的结果，我们描述了多梳蛋白家族蛋白Ring1b在非同源末端连接（NHEJ）介导的端到端染色体融合中的关键作用。我们表明，Ring1b水平降低的细胞修复无帽端粒染色质的能力降低。我们的数据代表了对正在经历DNA损伤的染色质的无偏分离，是绘制响应DNA损伤激活时染色质组成变化的宝贵资源。
