RNA依存型RNAポリメラーゼIIの活性性の分子基礎である
Elisabeth Lehmann1, Florian Brueckner, Patrick Cramer
1Gene Center Munich and Center for integrated Protein Science (CiPSM), Department of Chemistry and Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
Nature
|November 16, 2007
まとめ
RNAポリメラーゼII (Pol II) は,古代の複製酵素として作用する,固有のRNA依存型RNAポリメラーゼ (RdRP) 活性を示す. この発見は,Pol IIがRNA複製酵素から進化したことを示唆し,分子進化の理解におけるギャップを埋める.
科学分野:
- 分子生物学は分子生物学である.
- バイオケミストリー バイオケミストリー
- 進化生物学の進化生物学について
背景:
- RNAポリメラーゼII (Pol II) は,トランスクリプション中のDNAに依存したRNA合成で主に知られています.
- 証拠によると,Pol IIはRNA依存型RNAポリメラーゼ (RdRP) 活動をもっている可能性があり,ウイルスのRNA複製に関与している.
研究 の 目的:
- 浄化されたRNAポリメラーゼIIの固有RdRP活性を実証し,特徴づけること.
- Pol IIのRdRP機能の構造的およびメカニズム的基礎とその進化的影響を解明する.
主な方法:
- 精製されたPol II,RNAテンプレート,核酸三リン酸塩を用いたインビトロ検査.
- RNAテンプレート-製品デュプレックスでPol IIの構造を決定するX線結晶学.
- RdRP活動の調節における転写因子IIS (TFIIS) の役割を調査する.
主要な成果:
- Pol IIはRNAテンプレートを使用して内在的なRdRP活性を示し,活性サイトがDNA依存の転写サイトを重複する.
- RdRPの活動は,DNA依存の転写よりも遅い,プロセスが少ない.
- TFIISは,HDV抗原型のテンプレートでの分裂と拡張を容易にし,RNA複製の役割を示唆しています.
結論:
- Pol IIには固有のRdRP活性があり,古代のRNA複製酵素と類似して機能しています.
- この発見は,Pol IIがRNAゲノム複製酵素から進化したことを示唆する分子リンクを提供する.
- Pol IIのRdRP活動は,遺伝子発現とRNA複製メカニズムの進化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 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...
RNA Polymerase II Accessory Proteins
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...
RNA Polymerase II Accessory Proteins
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...
Bacterial RNA Polymerase
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity.
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...


