自然単一ガイドRNAは,CRISPR-Cas発現を自己調節するためにCas9を再利用する
Rachael E Workman1, Teja Pammi1, Binh T K Nguyen1
1Department of Molecular Biology & Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Cell
|January 9, 2021
まとめ
CRISPR-Casシステムは,独自のプロモーターを抑制する自然単一ガイドRNAによって制御され,ウイルス免疫と自己免疫毒性をバランスとします. この自己調節はタイプII-Aシステムで広く存在し,水平遺伝子転送を助長する.
科学分野:
- 微生物学
- 分子生物学
- 遺伝学
背景:
- CRISPR-Casシステムは,外来遺伝子要素に対するプロカリオットの適応免疫を与えます.
- 自己標的化 (自己免疫) を防ぐためにCRISPR- Casシステムを調節するメカニズムは,ほとんど不明である.
研究 の 目的:
- *Streptococcus pyogenes*におけるCRISPR-Casシステムの規制メカニズムを調査する.
- CRISPR-Casシステムの調節におけるトランス活性化RNA (tracrRNA) の役割を明らかにする.
主な方法:
- 長型トランスアクティブCRISPRRNA (tracr-L) の構造分析
- トラクル-LがCas9の活性とプロモーター抑制に与える影響を評価する機能試験.
- II-A型CRISPR-CasシステムにおけるtracrRNA媒介による自己調節のバイオ情報分析
主要な成果:
- tracr- Lは天然の単一ガイドRNAとして作用し,Cas9を自身のプロモーター (Pcas) を抑制するように指示する.
- Pcasの抑制は抗ウイルス免疫の 3,000 倍増加につながりますが,自己免疫毒性も高まります.
- II-A型CRISPR-Casシステムでは,tracrRNA媒介による自己調節が一般的であることを示す証拠がある.
結論:
- 自然単一ガイドRNAによるCRISPR-Casシステムの新規のパラダイムが明らかになった.
- この自己調節メカニズムは 強化された免疫の利点と 自己免疫のリスクをバランスします
- この発見は,CRISPR-Casシステムの新しい宿主への頻繁な水平移転を説明するかもしれない.
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