CRISPR-Casシステムは,ウイルスのDNAを注入して,適応免疫を確立し維持します
Joshua W Modell1, Wenyan Jiang1, Luciano A Marraffini1
1Laboratory of Bacteriology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
Nature
|March 30, 2017
まとめ
クラスタリングされた定期的な間隔の短いパリンドロミックリピート (CRISPR) - カスシステムは,感染中に侵入したファグから新しいDNAスペーサーを取得します. 特に早期に注入されたDNAから得られたこのタイミングは ウイルスの脅威に対する細菌の免疫力を高めます
科学分野:
- 微生物学
- 分子生物学
- 免疫学
背景:
- CRISPR-Casシステムは,侵入する核酸を認識し,除去するために,スペーサー配列を使用するプロカリオート免疫メカニズムです.
- スパッサー獲得はCRISPR免疫の重要なステップで,異なったDNA断片を宿主CRISPRロカスに統合することを意味します.
- ウイルスの感染時のスペーサー獲得のタイミングと特定のゲノム位置は,大部分は特徴づけられていない.
研究 の 目的:
- バクテリオファグの感染時のスタフィロコッカス・オーレウスの間隔器の獲得の時間的動態を調査する.
- ウイルスのライフサイクルのどの段階がスペーサーの獲得に 責任があるかを決定する.
- CRISPR- Cas9 免疫の有効性に対するスペーサー獲得場所の影響を評価する.
主な方法:
- スタフィロコーカス・オーレウス菌株のCRISPR-Cas9システムによる感染
- ミュータントファージを用いた新しいスペーサー獲得の追跡と注入されたDNAの分析.
- CRISPR- Cas9による免疫の評価は,得られた隔離器の起源に基づいています.
主要な成果:
- バクテリオファージの感染直後に発生し,注入されたウイルスのDNAのコスサイトから優先されます.
- DNA注入段階で得られたもので,複製や包装の過程では得られなかった.
- 早期に注射されたゲノム領域から派生したスペーサーは,後期に注射された領域から派生したスペーサーと比較して優れた免疫力を授与しました.
結論:
- CRISPR-Casシステムは,免疫反応の有効性を最大化するために,ファグ感染サイクルの初期に戦略的に距離隔離器を取得します.
- スパッサーの獲得のタイミングと場所は,ファグに対するCRISPR媒介の細菌防御を最適化するために重要です.
- ファージのライフサイクルと CRISPR 免疫の相互作用を理解することで,プロカリオットの防御戦略の洞察が得られます.
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