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Dual Immunofluorescence of γH2AX and 53BP1 in Human Peripheral Lymphocytes
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53BP1-RIF1-シールドインは,CSTおよびPolα依存のフィールインを通じてDSB切除に対抗する
Zachary Mirman1, Francisca Lottersberger1,2, Hiroyuki Takai1
1Laboratory for Cell Biology and Genetics, Rockefeller University, New York, NY, USA.
Nature
|July 20, 2018
まとめ
CTC1-STN1-TEN1 (CST) 複合体は,ポリメラーゼアルファと作用し,切除を防ぐことによってDNAの二重鎖破裂修復を制御する. このメカニズムは,BRCA1変異性がんにおいて極めて重要です.
科学分野:
- DNA 修復メカニズム
- 癌の遺伝学
- 分子生物学
背景:
- DNAの二重鎖断裂 (DSB) は,同質指向修復 (HDR) または非同質末端結合 (NHEJ) により修復される.
- BRCA1変異がんは,最小限のDSB切除により,HDRが欠乏し,PARP1阻害剤の感受性を引き起こす.
- 53BP1,RIF1,シールディン複合体は,BRCA1欠乏細胞におけるDSB切除を防ぐことが知られている.
研究 の 目的:
- 53BP1-RIF1-shieldinがDSB修復中に3'オーバーハングを生成するメカニズムを解明する.
- DNA修復経路の選択を制御する53BP1経路のダウンストリームエフェクターを特定する.
主な方法:
- CTC1-STN1-TEN1 (CST) コンプレックスとシールドインの相互作用とDNA損傷部位への局所化を調査した.
- CSTの枯渇がDSBの切除とRAD51の負荷に与える影響を評価した.
- BRCA1欠乏細胞におけるPARP1阻害剤の有効性に対するCSTおよびポリメラーゼアルファ阻害の影響を調査した.
主要な成果:
- CST複合体は,ポリメラーゼアルファで機能し,53BP1経路のダウンストリームエフェクタとして作用する.
- CSTはシールドインと相互作用し,53BP1およびシールドインに依存した方法でDNA損傷部位に局所する.
- CSTまたはポリメラーゼアルファの減少は,RAD51の負荷を阻害することによって,BRCA1欠乏細胞におけるPARP1阻害剤の有効性を高め,影響する.
結論:
- CST-ポリメラーゼ-アルファ複合体はフィールイン合成を媒介し,53BP1,RIF1,シールドインと併用してDSB修復経路の選択を制御する.
- この経路は,BRCA1欠乏性がんにおけるPARP1阻害剤に対する感受性の決定的な決定因子である.
- CST-Polα経路をターゲットにすることで,BRCA1変異がんの治療戦略を提供することができる.
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