在DNA复制原始授权期间,在DNA周围协同加载Mcm2-7双重六合体
Dirk Remus1, Fabienne Beuron, Gökhan Tolun
1Clare Hall Laboratories, Cancer Research UK London Research Institute, South Mimms EN6 3LD, UK.
Cell
|November 10, 2009
概括
对DNA复制起源的许可涉及将小染色体维护蛋白 (Mcm2-7) 装入预复制复合体. 这项研究揭示了Mcm2-7形成了沿着DNA滑动的双重六合体,这对于复制启动至关重要.
科学领域:
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
- 生物化学 生物化学
背景情况:
- 细胞DNA复制原产地许可证确保每个细胞周期只有一次复制.
- 这一过程涉及将微染色体维护蛋白 (Mcm2-7) 装入预复制复合体 (pre-RCs).
- 在RCs前,Mcm2-7形成了复制DNA酶的非活性核心.
研究的目的:
- 复制和生物化学分析Mcm2-7在DNA上的负载.
- 在加载过程中阐明Mcm2-7的结构组织.
- 了解Mcm2-7加载的机制及其对DNA复制启动的影响.
主要方法:
- 清洁正在芽的酵母蛋白. 清洁正在芽的酵母蛋白.
- 生物化学复制试验对Mcm2-7进行加载.
- 电子显微镜用于结构分析.
主要成果:
- 通过使用纯化蛋白质成功复制了Mcm2-7载荷.
- 证明了Cdt1*Mcm2-7的合作加载.
- 揭示了稳定的,头对头的Mcm2-7双六合体的形成,DNA通过中央通道.
- 显示装载的Mcm2-7可以被动地沿着双链DNA滑动.
结论:
- 该研究提供了对Mcm2-7加载的详细机制理解.
- 这些发现澄清了在复制起源处不活性酶加载的结构基础.
- 这项工作对理解复制原点选择,复制体组合和DNA解具有重大意义.
相关概念视频
01:29Replication in Eukaryotes
In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high fidelity before cell division, so there are many proteins that fulfill specialized roles in the replication process. Replication occurs in three phases: initiation, elongation, and termination, and ends with two complete sets of chromosomes in the nucleus.
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...
Many Proteins Orchestrate Replication at the Origin
Eukaryotic replication follows many of the same...
02:31Replication in Eukaryotes
Overview
02:38S-Cdk Initiates DNA Replication
The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
02:38S-Cdk Initiates DNA Replication
The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
02:37Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
02:31Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...