Defective chromatin recruitment and retention of NHEJ core components in human tumor cells expressing a Cyclin E fragment.
Defective chromatin recruitment and retention of NHEJ core components in human tumor cells expressing a Cyclin E fragment.
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DOI：
10.1093/nar/gkt812
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发表时间：
2013-12
影响因子：
14.9
通讯作者：
Almasan A
中科院分区：
文献类型：
--
作者：
Chatterjee P;Plesca D;Mazumder S;Boutros J;Yannone SM;Almasan A
暴露于电离辐射 (IR) 等基因毒性物质会产生双链断裂，在哺乳动物细胞中主要通过非同源末端连接 (NHEJ) 进行修复。 Ku70 被鉴定为蛋白水解细胞周期蛋白 E (CycE) 片段 p18CycE 的相互作用伙伴。 p18CycE 在 IR 诱导白血病细胞凋亡过程中的内源生成及其在对 IR 敏感的上皮肿瘤细胞中的稳定表达。 γH2AX IR 诱导灶 (IRIF) 和彗星测定表明 p18CycE 表达细胞中 NHEJ DNA 修复无效。 DNA Pull-down 和染色质募集实验表明，NHEJ 因子对双链断裂的保留减少了，但募集却没有减少。类似地，磷酸化T2609和S2056-DNA-PKcs及其靶标S1778-53BP1的IRIF在表达p18CycE的细胞中大大降低。结果，DNA-PKcs 染色质关联也增加。当白血病细胞和稳定表达 p18CycE 的上皮细胞中产生 p18CycE 时，53BP1 IRIF 受到抑制。共济失调毛细血管扩张突变被激活，但其 53BP1 和 MDC1 靶点未被激活。这些数据表明 p18CycE 通过干扰 DNA-PKcs 构象和/或二聚化对 NHEJ 产生深远影响，这是有效 DNA 修复所必需的，从而使表达 p18CycE 的细胞对 IR 更加敏感。这些研究为人类肿瘤细胞中 NHEJ 失调提供了独特的机制见解，其中 NHEJ 核心成分的缺陷很少见。
Exposure to genotoxic agents, such as ionizing radiation (IR), produces double-strand breaks, repaired predominantly in mammalian cells by non-homologous end-joining (NHEJ). Ku70 was identified as an interacting partner of a proteolytic Cyclin E (CycE) fragment, p18CycE. p18CycE endogenous generation during IR-induced apoptosis in leukemic cells and its stable expression in epithelial tumor cells sensitized to IR. γH2AX IR-induced foci (IRIFs) and comet assays indicated ineffective NHEJ DNA repair in p18CycE-expressing cells. DNA pull-down and chromatin recruitment assays revealed that retention of NHEJ factors to double-strand breaks, but not recruitment, was diminished. Similarly, IRIFs of phosphorylated T2609 and S2056-DNA-PKcs and its target S1778-53BP1 were greatly decreased in p18CycE-expressing cells. As a result, DNA-PKcs chromatin association was also increased. 53BP1 IRIFs were suppressed when p18CycE was generated in leukemic cells and in epithelial cells stably expressing p18CycE. Ataxia telangiectasia mutated was activated but not its 53BP1 and MDC1 targets. These data indicate a profound influence of p18CycE on NHEJ through its interference with DNA-PKcs conformation and/or dimerization, which is required for effective DNA repair, making the p18CycE-expressing cells more IR sensitive. These studies provide unique mechanistic insights into NHEJ misregulation in human tumor cells, in which defects in NHEJ core components are rare.
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影响因子：
4.8
作者：
Chen, Benjamin P. C.;Uematsu, Naoya;Chen, David J.
通讯作者：
Chen, David J.
DOI：
10.1042/bj20080413
发表时间：
2009-02-01
期刊：
The Biochemical journal
影响因子：
--
作者：
Mahaney BL;Meek K;Lees-Miller SP
通讯作者：
Lees-Miller SP
影响因子：
3.8
作者：
Noon, Angela T.;Goodarzi, Aaron A.
通讯作者：
Goodarzi, Aaron A.
影响因子：
5.3
作者：
Mazumder, Suparna;Plesca, Dragos;Almasan, Alexandru
通讯作者：
Almasan, Alexandru
影响因子：
5.3
作者：
Neal, Jessica A.;Dang, Van;Meek, Katheryn
通讯作者：
Meek, Katheryn