SフェーズサイレンスL1要素における親H3K9me3の非対称分布
Zhiming Li1,2,3,4, Shoufu Duan1,2,3,4, Xu Hua1,2,3,4
1Institute for Cancer Genetics, Columbia University Irving Medical Center, New York, NY, USA.
Nature
|November 8, 2023
まとめ
ヒストンH3ライシン9トリメチル化 (H3K9me3) は,複製中に,特にLINEレトロトランスポゾンで,優先的に主要なDNA鎖に転送されます. この非対称なH3K9me3分布は,HUSH複合体とPol εによって媒介され,重複する要素を静止します.
科学分野:
- エピジェネティクス
- 分子生物学
- ゲノミクス
背景:
- 繰り返し発生するDNA配列は,ヒストンH3ライシン9トリメチル化 (H3K9me3) によって静止されます.
- この沈黙の喪失は ゲノム不安定や癌や老化につながるのです
- DNA複製中のH3K9me3分割のメカニズムは不明である.
研究 の 目的:
- 複製するDNA鎖で親のH3K9me3の分割のパターンとメカニズムを調査する.
- H3K9me3が複製過程で 新しく合成されたDNAにどのように配分されるかを理解するためです
- H3K9me3の非対称性による反復要素の静止作用を解明する.
主な方法:
- 細胞および分子生物学技術を用いて複製フォークでH3K9me3の分布を調査した.
- HUSH複合体とDNAポリメラーゼPol εの役割を研究するために遺伝的アプローチを使用した.
- HUSH複合体の成分とPol εサブユニットの突然変異がH3K9me3の非対称性と重複要素発現に与える影響を分析した.
主要な成果:
- H3K9me3は,複製過程で,特に長い核元素 (LINE) のレトロトランスポーズで,リードDNA鎖に優先的に転送されます.
- ヒト静音ハブ (HUSH) 複合体はDNAポリメラーゼPol εと相互作用し,非対称なH3K9me3分離を保証する.
- Pol εサブユニットまたはHUSH複合体の欠乏は,H3K9me3の非対称性およびLINE発現の増加を引き起こす.
結論:
- HUSH複合体は,Pol εと結合して,S相のLINEでの非対称なH3K9me3分布を促進する.
- このメカニズムは 繰り返しの要素の発現を抑制し ゲノムの安定性を維持するために不可欠です
- この発見は,DNA複製中に表遺伝子遺伝と 遺伝子サイレンシングの新たなメカニズムを明らかにした.
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