DNA复制环的动力学揭示了滞后链合成的时间控制
Samir M Hamdan1, Joseph J Loparo, Masateru Takahashi
1Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA.
Nature
|November 26, 2008
概括
DNA复制面临着一个方向性挑战. 这项研究可视化了菌体T7中的复制循环,揭示了原料合成和Okazaki片段完成触发循环释放,确保了复制体重置.
科学领域:
- 分子生物学分子生物学
- 生物物理学的生物物理.
- 遗传学 是一个遗传学.
背景情况:
- DNA复制需要在反平行链上进行协调合成.
- 滞后链合成产生的Okazaki碎片由于DNA的反平行性质.
- 滞后链中的复制循环有助于克服 prokaryotes 中的方向性问题.
研究的目的:
- 在实时中可视化和分析复制循环动态.
- 了解复制循环形成和释放的触发因素.
- 为了研究DNA复制的协调由个体复制体.
主要方法:
- 使用单分子技术观察个体复合体.
- 进行了复制循环形成和释放的实时可视化.
- 对循环大小分布和滞后时间的分析提供了动态见解.
主要成果:
- 在细菌 T7 DNA 复制过程中,实时可视化复制循环.
- 启动原料合成和完成Okazaki片段的启动都会触发循环释放.
- 分析了循环大小和循环之间的延迟时间.
结论:
- 复制循环的动态对于协调的滞后链合成至关重要.
- 循环释放的双触发器可以确保高效的复制组重置.
- 这种机制突出了DNA复制忠实性的安全系统.
相关概念视频
01:59Lagging Strand Synthesis
During replication, the complementary strands in double-stranded DNA are synthesized at different rates. Replication first begins on the leading strand. Replication starts later, occurs more slowly, and proceeds discontinuously on the lagging strand.
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
01:59Lagging Strand Synthesis
During replication, the complementary strands in double-stranded DNA are synthesized at different rates. Replication first begins on the leading strand. Replication starts later, occurs more slowly, and proceeds discontinuously on the lagging strand.
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
There are several major differences between synthesis of the leading strand and synthesis of the lagging strand. 1) Leading strand synthesis happens in the direction of replication fork opening, whereas lagging strand synthesis happens in the...
03:01The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
03:01The Replisome
DNA replication is carried out by a large complex of proteins that act in a coordinated matter to achieve high-fidelity DNA replication. Together this complex is known as the DNA replication machinery or the replisome.
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
The synthesis of the leading and lagging strands is a highly coordinated process. To explain this, the “Trombone model” was proposed by Bruce Alberts in 1980. The DNA loop formation starts when a primer is synthesized on the parent lagging strand. The loop grows with the...
02:40DNA Replication
DNA replication involves the separation of the two strands of the double helix, with each strand serving as a template from which the new complementary strand is copied. After replication, each double-stranded DNA includes one parental or “old” strand and one “new” strand. This is known as semiconservative replication. The resulting DNA molecules have the same sequence and are divided equally into the two daughter cells.
Replication in Prokaryotes
DNA replication uses a large number of...
Replication in Prokaryotes
DNA replication uses a large number of...
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...