非最適のコドン使用は,日中時計の条件を満たすためのメカニズムです
Yao Xu1, Peijun Ma, Premal Shah
1Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, USA.
Nature
|February 19, 2013
まとめ
サイアノバクテリアは,非最適の遺伝子コードンを利用して,昼夜リズムを制御し,環境の変化に適応します. 最適なコドンに対するこの自然選択は,昼間の振幅を調節することにより,フィットネスを最適化し,コドン使用に関する以前の仮定に異議を唱えます.
科学分野:
- 分子生物学は分子生物学である.
- クロノバイオロジーはクロノバイオロジーを用います.
- 進化生物学の進化生物学について
背景:
- シルカディアンリズムは,日常の環境サイクルに適応するために不可欠な生物学的振動です.
- シアノバクテリアでは,KaiABCタンパク質が,日中時計振動器の核を形成する.
- 最適なコドン使用は,通常,重要な遺伝子の翻訳効率を高めますが,kaiBC遺伝子はバイアスを示します.
研究 の 目的:
- Synechococcus elongatus.における昼間リズム条件の分子基礎を調査する.
- 昼間の遺伝子発現の調節における非最適のコドン利用の役割を決定する.
- 環境条件に反応するコドン使用バイアスの適応的意義を探求する.
主な方法:
- KaiBC遺伝子配列の実験的な最適化により,KaiBとKaiCのタンパク質発現を高める.
- 異なる温度で固有の昼夜リズムを評価する.
- 変化する温度と日中リズム条件下での細胞の健康状態の測定.
主要な成果:
- kaiBCコドン利用の最適化により,低温で固有のリズムが強化された.
- 細胞のフィットネスは,低温で昼夜リズムが抑制されたときに最高でした.
- 自然選択は,より涼しい環境では,堅固な昼夜系の抑制を好む.
結論:
- kaiBC遺伝子における非最適のコドン利用は,日中リズム振幅を調節する転写後のメカニズムとして作用する.
- このコドンベースの調節は,環境のシグナルに反応して,日中および非日中状態の間の適応的な切り替えを可能にします.
- この研究は,適応的な現象型変異と生物の適性のために最適なコドンに対する自然選択を示しています.
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