相关实验视频
Updated: May 11, 2026
07:27
Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Published on: April 30, 2010
复制分叉在阻塞的新生领先链的下游被重新激活
Ryan C Heller1, Kenneth J Marians
1Molecular Biology Program, Weill Graduate School of Medical Sciences of Cornell University, New York, New York 10021, USA.
Nature
|February 3, 2006
概括
即使没有修复的领先链病变,DNA复制也可以重新开始. 一个复制重启系统协调了两个链上的新DNA合成,使损伤绕过和有效复制受损的DNA模板.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 生物化学 生物化学
背景情况:
- 未修复的DNA病变对准确的DNA复制构成重大风险.
- 虽然重组依赖的分叉重新启动是可以理解的,但通过链特异性病变的复制仍然不太清楚.
研究的目的:
- 为了研究复制的机制,重新启动下游的未经维修的领先链块.
- 为了阐明,当新生的链的3'-OH不可用时,如何重新启动导链合成.
主要方法:
- 使用大肠杆菌复制系统.
- 研究了DnaB酶和DnaG原酶在分叉活性化中的作用.
主要成果:
- 证明复制可以重新启动,并且主要链合成可以在主要链块的下游重新启动.
- 显示,在滞后链模板上加载单个DnaB六合体,与DnaG primase的领先和滞后链原始化协调.
- 在复制分叉重新激活期间建立了绕过损坏的机制.
结论:
- 这项研究提供了一种机制,解释了紫外线辐射DNA复制过程中子链间隙如何形成相反的前导链病变.
- 这些发现解释了即使严重损坏的DNA模板的快速复制.
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02:31Replication in Eukaryotes
Overview
01:02The DNA Replication Fork
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
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...
01:02The DNA Replication Fork
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
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...
02:37Restarting 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...