领先链DNA聚合酶epsilon的校对外核酶可以防止复制叉在破碎的模板链上崩
Tasnim Ahmad1, Ryotaro Kawasumi1, Tomoya Taniguchi1
1Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan.
Nucleic acids research
|November 9, 2023
概括
在单端双链断裂的DNA复制叉逆转是由PARP1,CTF18和Polε外核酶调解的. 这一途径,独立于同质导向修复,是olaparib的目标,增强其在癌细胞中的细胞毒性.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 癌症研究 癌症研究
背景情况:
- 由聚合酶epsilon (Polε) 遇到单链断裂 (SSB) 的领先链DNA复制产生单端双链断裂 (seDSB).
- 同质导向修复 (HDR) 和叉反转 (FR) 是seDSB的关键修复途径,但seDSB的FR理解得很差.
- 众所周知,在seDSBs中对FR要求使用聚ADP-ribose) 聚合酶1 (PARP1).
研究的目的:
- 在单端双链断裂 (seDSBs) 上特定调解叉反转 (FR) 的分子.
- 研究Polε外核酶,CTF18和PARP1在对DNA损伤的反应中的功能相互作用.
- 阐明坎普托西因 (CPT) 和olaparib在癌细胞中细胞毒性的基础机制.
主要方法:
- 创建和分析各种淘汰细胞系,包括缺异核酶的POLE1exo-/-, CTF18-/-, PARP1-/-,以及它们的组合.
- 表观分析以确定Polε外核酶,CTF18和PARP1.1之间的功能关系.
- 在不同的突变细胞系中评估细胞对坎普托素 (CPT) 和olaparib的耐受性.
主要成果:
- 聚外核酶和CTF18被确定为seDSBs中FR的关键媒介,需要PARP1才能耐受坎普托西因 (CPT).
- 缺乏POLE1exo-/-) 的细胞表现出类似于缺乏HDR的BRCA1-/-细胞的CPT敏感性.
- 结合POLE1exo-/-和BRCA1-/-突变,导致了协同的CPT敏感性,表明了独立的途径.
结论:
- 确定了一种新的PARP1-CTF18-Polε外核酶轴,它独立于HDR作用,以防止seDSB中的叉子崩.
- 奥拉巴里布准了这个新发现的轴,解释了它在缺乏HDR的癌细胞中强大的细胞毒性.
- 了解这些独特的DNA修复途径为向癌症治疗策略提供了新的见解.
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