エクソソームによるRNAの分解は,核ポリアデニレーション複合体によって促進される
John LaCava1, Jonathan Houseley, Cosmin Saveanu
1Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3JR, UK.
Cell
|June 7, 2005
まとめ
核のTRAMP複合体は,RNAの分解のためにエクソソーム複合体を活性化します. このコファクタに依存するRNA処理は,eukaryotesにおけるrRNAとsnoRNA前駆体を分解するのに極めて重要です.
科学分野:
- 分子生物学は分子生物学である.
- RNA 生物学 RNA 生物学
- バイオケミストリー バイオケミストリー
背景:
- エクソソーム複合体である3'-5'エクソヌクレアゼは,RNAの成熟と品質管理に不可欠です.
- 浄化されたエクソソームは,インビトロ活性が限られていることが示され,迅速なRNA分解のためのコファクターの活性化が必要であることを示唆しています.
研究 の 目的:
- RNAの分解のためのエクソソーム複合体を活性化する核共因子を特定する.
- 特定された複合体のRNA処理と分解における役割を明らかにする.
主な方法:
- ポリアデニレーション複合体とそのエクソソームとの相互作用を特徴付けるための生化学的分析.
- RNAのポリアデニレーションと分解活動のインビトロ研究.
- TRAMP複合体の機能を評価するために,酵母におけるインビボ分析.
主要な成果:
- 分配型RNAポリアデニレーションを示す核ポリアデニレーション複合体TRAMP (Trf4p/Air2p/Mtr4p) の識別.
- TRAMPは,構造化RNA基板のエクソソーム媒介による分解を刺激する.
- TRAMPは,rRNAとsnoRNA前駆体 in vivoのポリアデニレーションと分解に不可欠である.
結論:
- TRAMP複合体は重要な共因子として作用し,効率的なRNA分解のためにエクソソームを活性化します.
- TRAMPによるポリアデニレーションは,おそらく,エクソソーム処理のためのRNA基板をプライム化し,RNA崩壊におけるポリアテネの祖先の機能を維持します.
- このメカニズムは,eukaryotic nucleiにおけるrRNAとsnoRNA前駆体のような特定のRNAタイプのターンオーバーに不可欠です.
関連する概念動画
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Nuclear Export of mRNA
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
Nonsense-mediated mRNA Decay
The Upf proteins that carry out nonsense-mediated decay (NMD) are found in all eukaryotic organisms, including humans. Each protein has an individual role, but they need to work in collaboration. Upf1 is an ATP-dependent RNA helicase that unwinds the RNA helix. Because Upf1 can unwind any RNA, Upf2 and Upf3 are required to help Upf1 discriminate between nonsense and normal mRNAs.
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
mRNA Stability and Gene Expression
The structure and stability of mRNA molecules regulates gene expression, as mRNAs are a key step in the pathway from gene to protein. In eukaryotes, the half-life of mRNA varies from a few minutes up to several days. mRNA stability is essential in growth and development. The absence of the proteins regulating its stability, such as tristetraprolin in mice, can cause systemic issues, including bone marrow overgrowth, inflammation, and autoimmunity.
Cis-acting Elements involved in mRNA stability
Cis-acting Elements involved in mRNA stability


