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Genetic Studies of Human DNA Repair Proteins Using Yeast as a Model System
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酵母DNAトポイソメラーゼ変異体における転写依存DNAスーパーコイリング
1Department of Biochemistry, SUNY, Stony Brook 11794.
Cell
|July 29, 1988
まとめ
イーストの研究では,DNAトポイソメラーゼIとIIはRNAポリメラーゼIIの転写に不可欠ではないが,トポイソメラーゼIは遺伝子発現中に生成されるスーパーコイルをリラックスさせるために不可欠であることを明らかにしている.
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トポイソメラーゼは,DNAトポロジーを管理する酵素です.
- RNAポリメラーゼIIによる転写は,DNAの解き放たれと逆転を伴う.
- トポイソメラーゼIとIIは,DNAの複製と転写に役割を果たします.
研究 の 目的:
- 酵母におけるRNAポリメラーゼIIによる転写におけるDNAトポイソメラーゼIとIIの役割を調査する.
- 転写中にDNAスーパーコイルが発生する時期と理由を判断する.
- 転写中のスーパーコイルのリラックスメカニズムを理解する.
主な方法:
- イーストDNAトポイソメラーゼ変異体 (top1とtop1-top2 ts変異体) の分析.
- 転写的に活性な遺伝子を運ぶプラズミドの分離と分析.
- 異なる突然変異の条件と温度下でのDNAスーパーコイリングレベルの観察.
主要な成果:
- トポイソメラーゼIもIIもRNAポリメラーゼII転写に欠かせない.
- 活性遺伝子を備えたプラズミドは,トポイソメラーゼI変異体で負のスーパーコイリングを蓄積する.
- スーパーコイリングは,活性化ではなく,転写の延長時に発生し,トポイソメラーゼIIとは独立しています.
- トポイソメラーゼIは,転写的に誘発されたスーパーコイルをリラックスするために必要です.
結論:
- トポイソメラーゼIは,トランスクリプションの延長中に生成されるDNAのスーパーコイルをリラックスするために不可欠です.
- トポイソメラーゼIが存在しない場合にスーパーコイリングを引き起こす正確なメカニズムについては,さらなる調査が必要である.
- トポイソメラーゼは,RNAポリメラーゼがテンプレートに沿って移動する際のDNAトポロジーの管理に不可欠です.
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