BAF複合体は,トポイソメラーゼIIαによるDNAの解鎖を促進する
Emily C Dykhuizen1, Diana C Hargreaves, Erik L Miller
1Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305, USA.
Nature
|May 24, 2013
まとめ
人間の癌の20%以上で変異したBAF複合体は,細胞分裂中のDNAの解鎖に不可欠です. トポイソメラーゼIIαとの相互作用により,染色体分離の誤差を防止し,腫瘍抑制作用を強調する.
科学分野:
- 細胞生物学 細胞生物学
- 遺伝学 遺伝学とは
- がん研究 がん研究
背景:
- BAF (BRG1関連因子) 複合体は,哺乳類のSWI/SNFとしても知られており,転写調節に関与するクロマチンのリモデラーです.
- BRG1 (SMARCA4) とBAF250a (ARID1A) を含むBAFサブユニットの変異は,ヒトの悪性腫瘍の20%以上で発生しますが,それらの腫瘍抑制機構は完全に理解されていません.
- 核ATPアゼのサブユニットであるBRG1は,幼児期の髄芽細胞腫とブルキットリンパ腫で頻繁に変異する.
研究 の 目的:
- ミトーシスにおけるBAF複合体のこれまで未知の機能を調査する.
- 染色体分離におけるBAF複合体の役割と,腫瘍抑制との関連を解明する.
- BAF複合体がトポイソメラーゼIIα (TOP2A) と相互作用するメカニズムを決定する.
主な方法:
- マウス細胞におけるBrg1のデレクションと,ヒトの腫瘍由来BRG1変異体の発現.
- G2/M段階とアナフェーズブリッジ形成に焦点を当てた細胞サイクル進行の分析.
- クロマチン免疫プレシピテーションアッセイは,ゲノム部位へのTOP2A結合を評価する.
- BAF複合体とTOP2Aとの相互作用を研究するための共免疫プレシピテーション.
主要な成果:
- Brg1の喪失または変異は,アナフェーズブリッジ形成とG2/M相ブロックにつながり,脱鎖の障害を示します.
- BAF複合体は,BAF250a経由で,TOP2Aと直接相互作用する.
- BAF複合体は,約12,000のゲノム部位へのTOP2A結合に不可欠である.
- TOP2Aの染色体結合は,BRG1のATPアゼ活性に依存しており,これは腫瘍性BRG1変異体では損なわれています.
結論:
- BAF複合体は,新たに複製された姉妹染色体の解鎖に重要な役割を果たし,適切な染色体分離に不可欠なプロセスです.
- BAF媒介によるTOP2A染色体結合と機能には,BRG1のATP酶活性が必要である.
- BRG1変異によるこのBAF-TOP2A相互作用の障害は,BAFサブユニットの腫瘍抑制機能に寄与する.
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