低CDK活动和APC/CC的增强退化
Fanghua Li1,2, Emil Mladenov1,3, Yanjie Sun1,2
1Institute of Medical Radiation Biology, University Hospital Essen, University of Duisburg-Essen, 45147 Essen, Germany.
Cells
|June 10, 2023
概括
替代末端结合 (alt-EJ) DNA 修复受CtIP水平的调节,这些CtIP水平在G1细胞中较低,在G0细胞中由于降解而无法检测到. 抑制CtIP降解恢复了G0细胞中的alt-EJ,保持了基因组稳定性.
科学领域:
- DNA 修复机制的修复机制
- 基因组稳定性 基因组稳定性
- 细胞周期调节细胞周期调节
背景情况:
- 替代端结合 (alt-EJ) 是一个易发生错误的DNA双链断裂 (DSB) 修复途径,当正规途径 (c-NHEJ,HR) 失败时,它就会活跃起来.
- Alt-EJ效率取决于细胞周期,在G2达到峰值,在G1降低,在静止的G0细胞最小.
- 细胞周期各个阶段,特别是G0中,对alt-EJ的精确调节仍然不清楚.
研究的目的:
- 为了研究调节G1和G0相细胞中的alt-EJ的机制.
- 在静止细胞中确定控制DNA双链断裂修复过程中alt-EJ的关键因素.
- 了解如何在非循环细胞中保持基因组稳定.
主要方法:
- 在暴露于电离辐射 (IR) 后,对G1和G0细胞的alt-EJ活性进行比较.
- 评估CtIP (C端结合蛋白相互作用蛋白) 水平及其在DNA末端切除中的作用.
- 药理上抑制CtIP降解 (博特佐米布) 和CDH1的遗传枯竭,以挽救G0细胞中的CtIP表达.
- 对G0细胞中CtIP的CDK (环素依赖激酶) 酸化的分析.
主要成果:
- 已确定CTIP依赖的DNA末端切除是G1和G0细胞中alt-EJ的关键调节器.
- 与G2细胞相比,G1细胞的低CtIP水平允许有限的切除和alt-EJ.
- 由于APC/C介导的降解,CtIP在G0细胞中无法检测到,显著抑制了alt-EJ.
- 抑制CtIP降解或CDH1枯竭可以恢复G0细胞中的CtIP和alt-EJ活性.
- 在G0中激活CtIP需要CDK依赖酸化,主要是通过CDK4/6.
结论:
- 在G0阶段细胞中抑制突变性alt-EJ是通过调节CtIP的降解来实现的.
- 这种机制对于在较高的真核生物中维持大量非循环细胞的基因组稳定性至关重要.
- 在整个细胞周期中,CTIP水平和活性受到严格控制,以平衡DNA修复忠实性和基因组完整性.
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