梅尔-戈林综合征突变会在DNA复制启动过程中损害MCM2-7复合体的负载
Yusong Liu1,2,3,4, Mengquan Yang2,3,4,5, Ping Lu2,3,4,5
1School of Life Sciences, Fudan University, Shanghai 200433, China.
概括
涉及MCM3蛋白的新发现的"安全"调节了复制酶 (MCM2-7) 在DNA上的加载. 这种锁可以防止DNA过早进入,确保正确的复制启动,并防止DNA损伤.
科学领域:
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
- 结构生物学 结构生物学
背景情况:
- MCM2-7复合体是DNA复制启动所必需的关键的复制酶.
- 将MCM2-7酶加载到DNA上需要与ORC,CDC6和CDT1.1进行相互作用.
- MCM2-7可以作为一个单个六合体 (SH) 或一个环绕DNA的双六合体 (DH) 存在.
研究的目的:
- 调查调节MCM2-7螺旋酶负荷的结构机制.
- 确定涉及防止过早DNA进入酶的新型调控元素.
- 了解这些调节机制对人类疾病的影响.
主要方法:
- 低温电子显微镜 (cryo-EM) 用于确定人类MCM2-7.2的结构.
- 生物化学试验研究MCM2-7与DNA和调节蛋白的相互作用.
- 位点定向突变发生,以扰乱MCM3安全锁,并评估功能后果.
- 细胞周期分析和DNA损伤测试,以评估突变的影响.
主要成果:
- 没有DNA的人类MCM2-7的一小部分存在于双重六合体 (DH) 中.
- MCM3 翅膀螺旋域 (WHD) 起到安全锁的作用,阻止DNA 进入 SH 和 DH 形式的中央通道.
- 需要ORC-CDC6结合才能打开安全锁,允许DNA进入.
- 影响MCM3安全锁的突变导致复制缺陷和DNA损伤检查点激活.
- 缩短MCM3链接器可以缓解由锁增强突变引起的细胞周期缺陷.
结论:
- 一个新的监管机制,包括一个MCM3介导的安全锁,控制MCM2-7的螺旋体负载.
- 这种锁可以防止过早的DNA结合,确保调节DNA复制的启动.
- 这种安全锁的调节失调与复制缺陷和DNA损伤有关,这对人类疾病有影响.
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