海洋ウイルスと宿主の全ゲノム表現ダイナミクスは,共進化の特徴を明らかにする
Debbie Lindell1, Jacob D Jaffe, Maureen L Coleman
1Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Nature
|September 7, 2007
まとめ
バクテリアウイルス (ファージ) と宿主が共進化し,ファージは宿主遺伝子を獲得する. この研究は,ファグが宿主の代謝遺伝子を複製のために利用し,それらを転送し,両方のゲノム進化を駆動することを明らかにしています.
科学分野:
- 微生物ゲノミクスと進化
- ウイルス学とファグと宿主の相互作用
- 海洋サイノバクテリアとサイノファージュ
背景:
- 細菌宿主とウイルス (ファージ) は,相互のゲノム進化に従事する.
- 菌根媒介による遺伝子転送,特にゲノム島からの遺伝子転送は,微生物の進化に大きく影響を与えます.
- ファージゲノムは,宿主から遺伝子を獲得することで形成されます.
研究 の 目的:
- 菌感染中にプロクロロコッカスMED4とシアノファージP-SSP7の全ゲノム発現を調査する.
- 海洋サイアノバクテリアとそのウイルスの共同進化過程を理解する.
- 細菌の代謝遺伝子をファグでコードする細菌代謝遺伝子の機能的役割を解明する.
主な方法:
- 海洋サイアノバクテリアの全ゲノム発現分析 プロクロロコッカスMED4とサイアノファージP-SSP7のリチス感染時の発現分析.
- バクテリアの代謝に関与するファグ遺伝子を含む共転写ファグ遺伝子の識別.
- ファグ感染中の宿主遺伝子のアップレギュレーションの分析と,サイノファグゲノムとの比較.
主要な成果:
- 4つのファグでコードされた細菌代謝遺伝子 (psbA, hli, talC, nrd) は,ファグのDNA複製遺伝子と共同で転写され,エネルギーとデオキシヌクレオチド生産のための機能的単位を形成しました.
- 多くの宿主遺伝子は,潜在的にストレス反応またはファグ誘発的であり,感染中にアップレギュレーションされた.
- 多くの上位調節された宿主遺伝子はゲノム島に位置し,シアノファージのゲノムに同類を持つ.
結論:
- ファージは,上調された宿主遺伝子を利用するために進化し,ファージゲノムに安定した組み込みを促進しました.
- このメカニズムにより,宿主遺伝子がファグを通して他の宿主に移転し,ゲノム島に寄与します.
- 宿主遺伝子のファグ誘発的活性化は,宿主およびファグゲノムの両方の遺伝子コンテンツの共同進化を導きます.
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