X染色体の不活性化は,Xist RNAの安定化によって媒介されます
B Panning1, J Dausman, R Jaenisch
1Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA.
Cell
|September 23, 1997
まとめ
女性の胚性幹細胞は,分化時にXist発現を調節する. 不活性X染色体 (Xi) でのXistRNAの安定化は,高い発現を促し,活性X染色体 (Xa) は低い発現を維持する.
科学分野:
- エピジェネティクス エピジェネティクス
- 遺伝学 遺伝学とは
- 発達生物学 発達生物学とは
背景:
- XistRNA発現は,雌性哺乳類のX染色体不活性化 (XCI) に不可欠である.
- 微分化前に,低レベルのXist発現は,両方の活性X染色体 (Xa) から発生する.
- 微分化すると,Xist発現は劇的に増加しますが,それは将来の不活性X染色体 (Xi) からのみです.
研究 の 目的:
- 発達的に調節されたXist発現を制御する規制メカニズムを解明する.
- 差別化過程でXistRNAレベルが活性X染色体と非活性X染色体の両方でどのように制御されているかを理解する.
主な方法:
- 女性胚性幹細胞におけるXistRNA発現レベルを,分化前と分化後の分析.
- Xistのトランスクリプトの安定化を調査しています.
- XaとXiの間のXist発現を差異的に調節する要因とメカニズムを特定する.
主要な成果:
- 分化細胞は,XiからXist発現を特異的に高めます.
- Xistトランスクリプトの安定化は,Xiにおける高レベルの発現のための重要なメカニズムです.
- XaでXistの安定化を阻害し,低レベルの発現を沈黙させるためのメカニズムが存在します.
結論:
- Xist発現の発達的調節には,Xiのトランスクリプトの安定化が含まれています.
- XaとXiの間のXistRNAの安定性の微分調節は,XCIにとって非常に重要です.
- 複数のメカニズムは,細胞分化中のXist発現変化を調整する.
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