53BP1通过不同的蛋白相互作用来调解生产性和变异性DNA修复
Elsa Callen1, Michela Di Virgilio, Michael J Kruhlak
1Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
Cell
|June 4, 2013
概括
DNA损伤反应 (DDR) 蛋白53BP1管理着DNA修复途径. 通过RIF1和PTIP对53BP1的酸化明显地控制了DNA修复,促进了免疫球蛋白类开关重组 (CSR) 并抑制了突变性修复.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 细胞生物学 细胞生物学
背景情况:
- DNA损伤反应 (DDR) 蛋白53BP1对于维持基因组稳定性至关重要.
- 53BP1在G1中起作用,防止过度的DNA末端切除,有利于非同类末端结合 (NHEJ) 而不是同类重组 (HR).
- 在S阶段,BRCA1对抗53BP1以促进HR,突出显示细胞周期依赖的DNA修复通路的调节.
研究的目的:
- 调查53BP1酸化在调节其与RIF1和PTIP相互作用中的作用.
- 确定特定的53BP1酸化位如何影响其在DNA修复和免疫球蛋白类开关重组 (CSR) 中的功能.
- 阐明RIF1和PTIP在调解53BP1的亲NHEJ和抗重组酶活动中的不同作用.
主要方法:
- 在关键的N-终端酸化位点产生和分析53BP1基突变 (53BP18A) 与氨酸替代.
- 在表达野生型53BP1与53BP18A的BRCA1缺乏细胞中评估基因组稳定性.
- 在表达53BP1变异的细胞中评估免疫球蛋白类开关重组 (CSR) 效率.
- 在野型53BP1和53BP18A.A.存在的情况下,对RIF1和PTIP招募到双链断裂 (DSB) 的调查.
主要成果:
- 53BP18A突变模仿了53BP1缺陷,在BRCA1缺陷细胞中恢复基因组稳定性.
- 53BP18A保留了招募RIF1的能力,但未能招募PTIP到DSB.
- 破坏PTIP复制了53BP18A突变体的影响,这表明PTIP对53BP1功能至关重要.
- 53BP18A在免疫球蛋白类开关重组 (CSR) 中表现得像野生型53BP1一样,表明酸化依赖调节.
结论:
- 53BP1促进生产性的CSR,并通过明显的依赖相互作用抑制突变性DNA修复.
- 53BP1的酸化决定了它与PTIP的相互作用,这对于其抑制突变性修复的作用至关重要.
- RIF1和PTIP调解53BP1的单独功能,表明DNA损伤反应中的复杂调节机制.
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