哺乳類の細胞におけるトポイソメラーゼII依存のG2サイクルチェックポイント
C S Downes1, D J Clarke, A M Mullinger
1Department of Zoology, University of Cambridge, UK.
Nature
|December 1, 1994
まとめ
DNAトポイソメラーゼIIは,完全な染色体凝縮に不可欠である. 明確な連鎖感受性チェックポイントは,DNA損傷制御とは別に,G2からの細胞サイクル出口を調節します.
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:
- DNAトポイソメラーゼIIは,複製中にDNA連鎖を解除し,染色体の凝縮に不可欠です.
- トポイソメラーゼII阻害剤は,通常,DNA損傷とチェックポイントの活性化により,G2段階の細胞を停止します.
- G2/M進行におけるトポイソメラーゼIIの正確な役割と,異なる細胞サイクルチェックポイントの存在は,現在も調査中です.
研究 の 目的:
- 完全な染色体凝縮と細胞サイクル進行のためにDNAトポイソメラーゼIIの必要性を調査する.
- G2/M細胞サイクル停止におけるトポイソメラーゼII活性とDNA損傷の役割を区別する.
- G2段階からの脱出を規制する規制メカニズムを特定する.
主な方法:
- ビスディオキシオピペラジン,特にICRF-193をDNA損傷のないトポイソメラーゼII阻害剤として利用した.
- G2の逮捕を回避するために,カフェインのようなチェックポイントを回避するエージェントを雇いました.
- 哺乳類の細胞における染色体凝縮と細胞サイクル進行を観察した.
主要な成果:
- ICRF-193はミトーシスへの入り口を遮断するが,G2からの出口は遮断しないので,最初のミトーシスへの入り口を超えてトポイソメラーゼIIの役割を示している.
- チェックポイントを回避する薬剤は,堕落した染色体凝縮を誘発し,トポイソメラーゼIIが完全な凝縮を必要とすることを確認しました.
- G2の出口は,G2のダメージチェックポイントとは独立した,連鎖感度の高いチェックポイントによって制御されていることが実証されました.
結論:
- DNAトポイソメラーゼIIは,完全に凝縮された染色体を達成するために不可欠です.
- 新しい連鎖感受性チェックポイントメカニズムは,G2段階からの進行を制御します.
- この連鎖に敏感なチェックポイントは,既定のG2ダメージチェックポイント経路とは異なる.
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