ユカリオットRNAポリメラーゼIIIの転写終結のメカニズム
Soren Nielsen1, Yulia Yuzenkova, Nikolay Zenkin
1Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Baddiley-Clark Building, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK.
まとめ
RNAポリメラーゼIII (Pol III) 終結は,ポリ-T信号だけでなく,トランスクリプト構造に依存しています. RNAの二次構造はPol IIIの放出を誘導し,細菌と共有する古代の終結機構を示唆しています.
科学分野:
- 分子生物学は分子生物学である.
- 遺伝学 遺伝学とは
- バイオケミストリー バイオケミストリー
背景:
- 遺伝子発現の調節は,細胞機能にとって極めて重要です.
- RNAポリメラーゼIII (Pol III) は,必須の非コーディングRNAを転写する.
- Pol III トランスクリプションの終止プロセスはよく理解されていません.
研究 の 目的:
- RNAポリメラーゼIIIによる転写終結のメカニズムを解明する.
- ポールIII延長複合体の放出を左右する要因を特定する.
- 転写終止機構の進化的保存を調査する.
主な方法:
- RNAポリメラーゼIIIのトランスクリプションの分析 in vitro.
- トランスクリプト構造とその終結における役割の調査.
- Pol IIIとバクテリアのRNAポリメラーゼ終結の比較分析.
主要な成果:
- Pol IIIトランスクリプト内の広範なRNA二次構造は,終結の鍵です.
- ポリ-T 終止信号は,Pol III の無効化とバックトラッキングを誘導する.
- RNA二次構造は,DNAテンプレートからPol IIIの放出を促進します.
- 終結メカニズムは,Pol IIIとバクテリアのRNAポリメラーゼとの類似性を示しています.
結論:
- Pol IIIの終結は,トランスクリプト媒介による放出を含む構造に依存するプロセスである.
- ヘアピン依存終結は,多様なRNAポリメラーゼで保存されている古代のメカニズムである可能性があります.
- Pol III 終結の理解は,遺伝子発現の調節と進化史についての洞察を提供します.
関連する概念動画
Eukaryotic RNA Polymerases
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
All three eukaryotic RNAPs require specific transcription factors, of which the...
Eukaryotic RNA Polymerases
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
All three eukaryotic RNAPs require specific transcription factors, of which the...
Transcription Attenuation in Prokaryotes
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...
Transcription in Prokaryotes
Transcription is a highly regulated process that converts genetic information into RNA molecules. The transcription cycle is divided into three key stages: initiation, elongation, and termination, each driven by specific molecular mechanisms.Initiation of TranscriptionIn bacteria, transcription begins when the RNA polymerase core enzyme associates with a sigma factor to form a holoenzyme. For example, the E. coli sigma factor called σ70 forms a holoenzyme, which recognizes the -10 (Pribnow box)...
Bacterial Transcription
RNA polymerase (RNAP) carries out DNA-dependent RNA synthesis in both bacteria and eukaryotes. Bacteria do not have a membrane-bound nucleus. So, transcription and translation occur simultaneously, on the same DNA template.
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Transcription Initiation
Initiation is the first step of transcription in eukaryotes. Prokaryotic RNA Polymerase (RNAP) can bind to the template DNA and start transcribing. On the other hand, transcription in eukaryotes requires additional proteins, called transcription factors, to first bind to the promoter region in the DNA template. This binding helps recruit the specific RNAP that can assemble on the DNA and start transcription.
The promoters and enhancers and their accessory proteins allow tight regulation of...
The promoters and enhancers and their accessory proteins allow tight regulation of...


