関連する実験動画
Updated: May 10, 2026

10:55
Study of the DNA Damage Checkpoint using Xenopus Egg Extracts
Published on: November 5, 2012
ATM-Chk2-Cdc25Aのチェックポイントの経路は,放射性耐性DNA合成に対して保護されます
J Falck1, N Mailand, R G Syljuåsen
1Institute of Cancer Bioloyg, Danish Cancer Society, Copenhagen, Denmark.
Nature
|April 12, 2001
まとめ
電離放射線 (IR) は,細胞サイクルチェックポイントを触発します. ATM-Chk2-Cdc25A-Cdk2経路は,DNA複製に不可欠なCdc25Aを分解することによって,放射性耐性DNA合成を防ぐ.
科学分野:
- 細胞生物学 細胞生物学
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
背景:
- ユカリオット細胞は,電離放射線 (IR) に反応して,細胞サイクルチェックポイントを活性化します.
- IR誘発のS相チェックポイントの欠陥は,ATM遺伝子変異を有するアタクシア・テランジエクタシア患者で観察された放射性耐性DNA合成につながります.
- Cdc25Aフォスファテーゼは,DNA合成のためにサイクリン依存キナーゼ2 (Cdk2) を活性化しますが,DNA損傷または複製ストレスで退化します.
研究 の 目的:
- ATM,Chk2,およびCdc25Aの機能的なリンクを調査し,S段階のチェックポイントを制御する.
- イオン化する放射線がCdc25Aの分解を誘発するメカニズムを解明する.
- ATM-Chk2-Cdc25A-Cdk2経路が放射性耐性DNA合成を防止する役割を決定する.
主な方法:
- 放射線によるCdc25Aの劣化におけるATMとChk2の役割を調査した.
- Chk2.2によるセリン123のCdc25Aのリン酸化を分析した.
- 癌に罹患しやすい患者の細胞系と腫瘍に関連したChk2アレルを利用して経路の機能を評価した.
主要な成果:
- イオン化放射線によるCdc25A破壊には,ATMとCdc25AのChk2媒介型リン酸化が,セリン123.3で必要である.
- IR後のCdc25Aタンパク質の喪失はCdk2の脱リン酸化を防止し,一時的なDNA複製ブロックを引き起こします.
- 腫瘍に関連したChk2アレル,Cdc25A上昇,またはCdk2AF変異体は,放射線照射時にDNA合成の抑制を損なう.
結論:
- ATM-Chk2-Cdc25A-Cdk2経路は,ゲノム整合性チェックポイントとして機能します.
- この経路は,放射性耐性DNAの合成を阻害する.
- Chk2は,このチェックポイントでの役割により,潜在的な腫瘍抑制剤として特定されています.
関連する概念動画
DNA Damage can Stall the Cell Cycle
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
Restarting 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...
The Spindle Assembly Checkpoint
The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
DNA Damage Can Stall the Cell Cycle
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
The Spindle Assembly Checkpoint
The spindle assembly checkpoint is a molecular surveillance mechanism ensuring the fidelity of chromosome segregation during anaphase. The checkpoint monitors the completion of all the prerequisite steps before chromosome segregation to determine whether the segregation process should proceed or be delayed.
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
Many proteins function together to control the spindle assembly checkpoint. Mutations affecting these proteins may allow cells to proceed into anaphase prematurely, resulting in the...
The Cell Cycle Control System
The cell cycle regulation directs how a cell proceeds from one phase to the next and begins mitosis. The cell cycle control system includes intracellular regulatory molecules and external triggers. They provide "stop" or "advance" signals and operate at specific cell cycle stages termed checkpoints to ensure that a particular process is completed before the cell advances to the next phase.
Cyclins and cyclin-dependent kinases (Cdks) are the primary cell cycle regulators and function at the cell...
Cyclins and cyclin-dependent kinases (Cdks) are the primary cell cycle regulators and function at the cell...

