トランジション状態の90S小リボソームサブユニット前駆体による冷凍-EM構造
Yifei Du1, Weidong An1, Xing Zhu1
1Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
まとめ
90Sプレリボソーム内の切断された5'外部転写されたスペーサー (5' ETS) RNAの分解は,小さなリボソームサブユニットの成熟を誘導する. このプロセスは核エクソソームとヘリコースMtr4を巻き込み,リボソームの生体生成を促進する.
科学分野:
- 分子生物学
- 構造生物学
- 細胞生物学
背景:
- 90Sプレリボソームは,小型のリボソームサブユニットのための重要な早期組立中間体です.
- 90S前リボソーム内の構造的再編成は,その成熟が40S前リボソームになるために不可欠である.
研究 の 目的:
- 90S 前リボソームから40S 前リボソームへの成熟を制御する構造的移行と分子メカニズムを解明する.
- この過程におけるRNAヘリゼDhr1と5' ETS分解の役割を調査する.
主な方法:
- 凍結電子顕微鏡 (Cryo-EM) を用いて,Saccharomyces cerevisiaeの中間物質の構造を決定した.
- RNAヘリケーズDhr1の削除を含む遺伝子操作が,移行経路を研究するために使用されました.
- 構造分析は90Sプレリボソーム,核エクソソーム,およびヘリコースMtr4の相互作用に焦点を当てた.
主要な成果:
- この研究は90Sから40S前の状態への経路における重要な構造的中間物質を特定した.
- RNAヘリケーズDhr1の削除は,完全な移行をブロックすることが判明しました.
- 90Sプレリボソーム内の切断された5' 外部転写区間器 (5' ETS) の劣化は,アセンブリ因子分解とリボソーム成熟の重要な要因として特定された.
- ヘリカゼMtr4で誘導された核エクソソームは,5' ETS消化のために準備されていることが観察されました.
結論:
- 5' ETSの分解は90S前リボソームの進行とリボソームの生殖において重要なステップである.
- 構造的な洞察は,RNAの分解機構と組み立て因子の調整された作用を明らかにします.
- このメカニズムは,小型のリボソームサブユニットの段階的な成熟と品質管理を保証します.
関連する概念動画
Cryo-electron Microscopy
4.0K
Conventional electron microscopy (EM) involves dehydration, fixation, and staining of biological samples, which distorts the native state of biological molecules and results in several artifacts. Also, the high-energy electron beam damages the sample and makes it difficult to obtain high-resolution images. These issues can be addressed using cryo-EM, which uses frozen samples and gentler electron beams. The technique was developed by Jacques Dubochet, Joachim Frank, and Richard Henderson, for...
4.0K
Ribosomes
9.6K
Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that synthesize large quantities of protein—such as secretory cells in the human pancreas—can contain millions of ribosomes.
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome...
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome...
9.6K
Ribosomes
73.5K
Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that synthesize large quantities of protein—such as secretory cells in the human pancreas—can contain millions of ribosomes.
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome...
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome...
73.5K
Ribosomal RNA Synthesis
14.3K
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
14.3K
Ribosomal RNA Synthesis
3.9K
3.9K
Termination of Translation
27.0K
The large ribosomal subunit has several important structures essential to translation. These include the peptidyl transferase center (PTC) - which is the site where the peptide bond is formed - and a large, internal, water-filled tube through which the nascent polypeptide moves. This latter structure is called the Peptide Exit Tunnel, and it begins at the PTC and spans the body of the large ribosomal subunit. During translation, as the nascent polypeptide chain is synthesized, it passes through...
27.0K


