マクロ分子転写処理複合体のアセンブリチャペロンとしてのtRNA
Julia Bartuli1, Stefan Jungwirth1, Manisha Dixit1,2
1Department of Biochemistry 1, Theodor Boveri-Institute, University of Würzburg, Würzburg, Germany.
Nature structural & molecular biology
|September 4, 2025
まとめ
移転RNA (tRNA) はポックスウイルス感染中にアセンブリチャペロンとして作用し,ウイルスのRNAポリメラーゼ複合体の形成を促進します. この新しい機能には,特定の,改変されていないtRNAGln/Argの結合とウイルスの転写因子の採用が含まれています.
科学分野:
- 分子生物学
- ウイルス学
- 構造生物学
背景:
- 転送RNA (tRNA) は,主にタンパク質翻訳における重要な役割で知られている.
- Mpoxウイルスなどのポックスウイルスは,複製のために独自のRNAポリメラーゼ (vRNAP) をコードします.
- ウイルスのマクロ分子複合体の正確な組み立てメカニズムは完全に理解されていません.
研究 の 目的:
- 翻訳を超えたtRNAの新しい機能を調査する.
- ポックスウイルスRNAポリメラーゼ (vRNAP) の組み立てにおける特定のtRNAの役割を解明する.
- tRNA がウイルス転写複合体形成を調節する構造的メカニズムを理解する.
主な方法:
- クリオ電子顕微鏡 (Cryo-EM) で,組み立ての中間物質を視覚化する.
- バイオケミカルアッセイで,tRNAの結合と因子の徴集を研究する.
- tRNA構造と改変パターンの分析
主要な成果:
- 特定されたtRNAGln/Argは,ポックスウイルスのvRNAPのためのアセンブリチャペロンとして特定の改変を欠いている.
- この改変されたtRNAが転写およびmRNA処理因子の採用を指揮することを示した.
- 非正規のtRNA構造を形成する,アンチコドン基 G36の内部化を含む誘発的適合メカニズムを明らかにした.
- このメカニズムは 開始前複合体への移行を制御します
結論:
- 転送RNA (tRNA) は,ウイルス複製におけるアセンブリ・チャペロンとして,以前は認識されなかった機能を有しています.
- tRNAGln/Argの特異的な結合と構造的適応は,ポックスウイルスのvRNAPの構成と機能に極めて重要です.
- このtRNA媒介の組み立てメカニズムは,病原性Mpoxウイルスに保存され,その生物学的重要性を強調しています.
関連する概念動画
Transfer RNA Synthesis
12.2K
One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases.
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
12.2K
Transcription Attenuation in Prokaryotes
16.0K
Transcriptional attenuation occurs when RNA transcription is prematurely terminated due to the formation of a terminator mRNA hairpin structure. Bacteria use these hairpins to regulate the transcription process and control the synthesis of several amino acids including histidine, lysine, threonine, and phenylalanine. Transcription attenuation takes place in the non-coding regions of mRNA.
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
16.0K
RNA Polymerase II Accessory Proteins
9.4K
Proteins that regulate transcription can do so either via direct contact with RNA Polymerase or through indirect interactions facilitated by adaptors, mediators, histone-modifying proteins, and nucleosome remodelers. Direct interactions to activate transcription is seen in bacteria as well as in some eukaryotic genes. In these cases, upstream activation sequences are adjacent to the promoters, and the activator proteins interact directly with the transcriptional machinery. For example, in...
9.4K
Protein Translocation Machinery on the ER Membrane
4.9K
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the...
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the...
4.9K
Protein Complex Assembly
2.1K
2.1K
ATP and Macromolecule Synthesis
6.1K
Biological macromolecules are organic compounds, predominantly composed of carbon atoms. The carbon atoms are covalently bonded with hydrogen, oxygen, nitrogen, and other minor elements. There are four major biological macromolecule classes: carbohydrates, lipids, proteins, and nucleic acids.
Most macromolecules are composed of single subunits, or building blocks, called monomers. The monomers combine with each other using covalent bonds to form larger molecules known as polymers.
Conversion of...
Most macromolecules are composed of single subunits, or building blocks, called monomers. The monomers combine with each other using covalent bonds to form larger molecules known as polymers.
Conversion of...
6.1K


