プライミング・ループと微分合成速度によるDNA複製の調整
Manjula Pandey1, Salman Syed, Ilker Donmez
1Department of Biochemistry, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA.
Nature
|November 20, 2009
まとめ
DNA複製は,協調したメカニズムを通じて,等しい鎖合成速度を達成します. RNAプライマーはDNA合成中に作られ,効率的なポリメラーゼの引き渡しと,より速い遅れた鎖の合成を保証するループを形成します.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
- バイオケミストリー バイオケミストリー
背景:
- DNA複製には,先行する鎖と後退する鎖の協調合成が必要です.
- 遅れた鎖はオカザキの断片を介して不連続で合成され,同等の合成速度に挑戦します.
研究 の 目的:
- 複製過程でDNA鎖の合成速度が等しくなるための調整メカニズムを解明する.
- ト7複製タンパク質が,先行性および後退性鎖の合成を調整する役割を調査する.
主な方法:
- DNA合成のダイナミクスを研究するためにT7複製タンパク質を使用した.
- 観察されたプライマーの合成とポリメラーゼの活性がリアルタイムで観察されました.
主要な成果:
- RNAプライマーは,進行中のDNA合成中に"オン・ザ・フライ"で合成されます.
- リードストランドポリメラーゼは,プライマー合成ではなくヘリカーゼ速度によって制限されます.
- プライミングループは,プライマース-ヘリカーゼと複製複合体の間の継続的な接触を容易にする.
- 遅れた鎖のポリメラーゼは,先導鎖のポリメラーゼよりも早くDNAを合成する.
結論:
- DNA複製を調整する3つのシナギスティックメカニズムは,同時進行するプライマー合成,効率的なハンドオフのためのプライミングループ,より速い遅滞鎖ポリメラーゼ活性です.
- これらのメカニズムは,リードストランドとレイグストランドのDNA合成の均等な純率を確保します.
- T7レプリソームは,プライマー合成中に一時停止することなくDNA合成を調整する.
関連する概念動画
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...
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...
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...
02:10Translesion DNA Polymerases
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...