ゲノム監視は,HUSH媒介によるイントロンレス移動要素の静音化
Marta Seczynska1, Stuart Bloor1, Sergio Martinez Cuesta2
1Cambridge Institute for Therapeutic Immunology and Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK.
Nature
|November 18, 2021
まとめ
ヒューマン・サイレッシング・ハブ (HUSH) コンプレックスは 侵入したDNAを 特定し,静止させ,レトロウイルスのように イントロンのない遺伝子要素をターゲットにします. このメカニズムは ゲノムを外来DNAから保護します
科学分野:
- 遺伝学
- 分子生物学
- エピジェネティクス
背景:
- ユカリオット細胞は,転写を制限する抑圧的なクロマチンの改変を用いて,侵入するDNAに対する防御メカニズムを有している.
- ヒューマン・サイレッシング・ハブ (HUSH) コンプレックスは,H3K9me3経由で長い間隔の要素-1レトロトランポゾン (L1s) とレトロウイルスを転写的に抑制することが知られている.
- HUSHがこれらの外来遺伝子要素を認識し,沈黙させられる正確なメカニズムは不明でした.
研究 の 目的:
- HUSH複合体が侵入遺伝子要素の転写抑制をどのように認識し,開始するか解明する.
- HUSH媒介による抑制におけるイントロンの役割を調査する.
- HUSH複合体のゲノム監視システムと 宿主遺伝子から外来DNAを区別する能力を理解するために
主な方法:
- HUSHの認識と抑制能力をテストするために,長い,イントロンレストランスゲンの範囲を使用しました.
- HUSH媒介による抑圧に対するイントロンの挿入の効果を,スプライシングなしで調べました.
- H3K9me3の堆積分析とゲノムデータを用いて,HUSHの結合と抑制の標的をマッピングした.
主要な成果:
- HUSHは,長い,イントロンレストランスゲンの広範な配列を認識し,トランスクリプションで抑制します.
- イントロン挿入は,スプライシングとは無関係にHUSH抑制を逆行させる.
- HUSHは,H3K9me3の堆積前に標的のトランスクリプトを結合し,標的のトランスクリプトはH3K9me3の開始と拡散に不可欠である.
- HUSHは,細胞の逆転移したmRNAから派生した内生性イントロンレス遺伝子のサブセットを抑制する.
結論:
- 侵入したレトロエレメントと宿主遺伝子を区別するためのHUSHの鍵となる機能としてイントロンレスcDNAが機能します.
- HUSHは,転写に依存するゲノム監視システムとして機能し,新しい外来DNAに対する即時の保護を提供します.
- このシステムは"非自己"DNAからゲノムを効果的に保護し,内生遺伝子の不適切な抑圧を防止します.
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