tRNAは,B. subtilisにおける転写アンチターミネーションのポジティブなレギュレータとして作用する
1Department of Biochemistry and Molecular Biology, Albany Medical College, New York 12208.
Cell
|August 13, 1993
まとめ
バシルスのtRNA合成酵素遺伝子は,トランスクリプションアンチターミネーションを調節に使用します. tyrS遺伝子の特定のコドンを変更すると,そのアミノ酸反応が変化し,tRNARNAが明らかになった.
科学分野:
- 微生物学 微生物学とは
- 分子生物学は分子生物学である.
- 遺伝子規制 遺伝子規制
背景:
- ほとんどのバシルス tRNA 合成酵素遺伝子は,共有された転写反終化メカニズムによって調節されます.
- 個々の遺伝子は,その特定のアミノ酸の制限に反応する.
- mRNAリーダー領域は,単一のアミノ酸特異のコードンを持つ保存された構造を示しています.
研究 の 目的:
- バシルス tRNA 合成酵素遺伝子の規制メカニズムを調査する.
- mRNAのリーダー配列における特定のコドンの役割を決定する.
- 遺伝子調節に関与するエフェクター分子を特定する.
主な方法:
- バシルスのtRNA合成酵素遺伝子におけるmRNAリーダー配列の比較分析.
- 特定のコードンを変化させる tyrS 遺伝子リーダー配列のサイト指向型変異.
- 異なるアミノ酸の制限下で遺伝子誘導のフェノタイプ分析.
- リジル-tRNAナンセンスサプレッサー変異体を用いた抑制分析.
主要な成果:
- tyrS遺伝子のコードンをUAC (チロシン) からUUC (フェニララリン) に変更すると,チロシン制限誘導は廃止され,フェニララリン制限誘導が与えられます.
- コドンより上流に追加の塩基を挿入しても,調節は影響されず,非翻訳的メカニズムを示唆した.
- リーダー配列のナンセンス・コドンは,誘導不可能なフェノタイプをもたらし,これはリジル-tRNA変異によって抑制可能であった.
結論:
- mRNAリーダー配列の特定のコードンは,tRNA合成酵素遺伝子のアミノ酸反応を決定する.
- 規制は,翻訳的でないメカニズムを通して行われます.
- 転送RNA (tRNA) は,この調節経路におけるエフェクタ分子として作用する.
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