E. coliのrRNA転写のアンチターミネーションは,ラムダナッツのような配列を含むコントロール領域セグメントによって引き起こされます
Cell
|October 1, 1984
まとめ
研究者らは,E. coliの特定のDNA断片を特定し,リボソームのRNA転写終了を制御しています. この発見は,バクテリオファージ・ラムダが利用するメカニズムに似たメカニズムを明らかにし,遺伝子発現の調節に影響を与えています.
科学分野:
- 分子生物学は分子生物学である.
- 微生物学 微生物学とは
- 遺伝学 遺伝学とは
背景:
- 細菌の転写終結は,特定のDNA配列とタンパク質によって制御されます.
- アンチターミネーションシステムは,リボソームのRNA (rrn) オペロンを含む特定の遺伝子の発現に不可欠です.
- ラムド菌類のバクテリオファージは,遺伝子発現の調節のためにアンチターミネーションシステムを利用します.
研究 の 目的:
- Escherichia coli (E. coli) のリボソームRNAトランスクリプションにおけるアンチターミネーションシステムを特定し,特徴づけること.
- E. coli rrnの絶滅防止システムと,ラムド型細菌菌体で見つかったものを比較する.
- rrnG制御領域内の特定のDNA配列が転写終結を調節する機能的役割を調査する.
主な方法:
- 遺伝子融合プラズミッドを用いたインビボ実験.
- ラックおよびハイブリッドのtrp-lacプロモーターを用いた転写終止効率の分析.
- サイト指向型変異と,重要なDNA断片の方向転換.
主要な成果:
- rrnG P2プロモーターを下流にある67 bpの制限断片は,転写終了を約50%大幅に減少させた.
- この断片は,ラムダN利用 (ナッツ) のロキュイに類似する配列 (ボックスA,B,C) を含んでいます.
- 断片は異質プロモーターからの転写ターミネーターの読み込みを媒介し,アンチターミネーション活性を示した.
- 断片を通過するトランスレーションまたはその方向の逆転時に,アンチターミネーション活動の喪失が観察されました.
結論:
- 特定された67bpの断片は,E. coliの絶滅防止システムの重要な構成要素として機能しています.
- E. coli rrn オペロンは,バクテリオファージ・ラムダが使用するシステムと類似したアンチターミネーションメカニズムを使用しています.
- これは,細菌およびそのファグのアンチターミネーションを通じて遺伝子発現を調節する保存されたメカニズムを示唆しています.
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