DNAメチルトランスフェラーゼによる高頻度突然変異
J C Shen1, W M Rideout, P A Jones
1Department of Biochemistry and Molecular Biology, Kenneth Norris, Jr., Comprehensive Cancer Center, University of Southern California, School of Medicine, Los Angeles 90033.
Cell
|December 24, 1992
まとめ
ハピルメチラゼは,DNAのCからUの変異を誘導する. この酵素は,
科学分野:
- 分子生物学は分子生物学である.
- 酵素学 酵素学とは
- 遺伝学 遺伝学とは
背景:
- DNAメチル化は遺伝子調節に不可欠です.
- DNA (サイトシン-5) - メチルトランスファーゼ (DNMTs) は,DNAメチル化を触媒する酵素である.
- HpaIIメチラゼ (M. HpaII) は,CCGG配列を認識するDNMTである.
研究 の 目的:
- HpaIIメチラゼの変異性の可能性を調査する.
- M. HpaIIによって引き起こされる変異のメカニズムを探求する.
- M. HpaIIの活動におけるS-アデノシルメチオニン (SAM) の役割を決定する.
主な方法:
- ミュータントのpSV2-neoプラズミドをM. HpaIIでインビトロでインキュベーションする.
- 改変されたプラズミドを uracil-DNA glycosylase が欠けている細菌に変容させる.
- 異なるSAM濃度での変異頻度分析.
主要な成果:
- M. HpaIIは,二重鎖DNAにおける高頻度のCからUへの移行変異を直接誘導した.
- uracil-DNA glycosylaseが欠けているバクテリアでは,逆転率の10 ^ 4倍の増加が観察されました.
- 変異頻度はSAM濃度に対して非常に敏感であり, >300 nMで減少した.
結論:
- M. HpaIIは,CからUへの移行を誘導することによって,変異原体として作用することができます.
- M. HpaIIによる酵素分解は,CpGサイトにおける変異ホットスポットに寄与する可能性があります.
- この発見は,メチルトランスフェラーゼとサイトシンの間の共性複合体の形成モデルを支持する.
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