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ファージラムダ遺伝子Qアンチターミネーターは,プロモーター付近のRNAポリメラーゼを認識し,一時停止部位を通して加速させます
Cell
|August 1, 1985
まとめ
ファージ・ラムダ・ゲンのQタンパク質は,トランスクリプション・アンチターミネーターとして作用し,特に RNAポリメラーゼと遅い遺伝子プロモーターで相互作用する. NusAタンパク質を必要とするこの相互作用により,ポリメラーゼは早期停止を克服し,転写を進めることができます.
科学分野:
- 分子生物学は分子生物学である.
- ウイルス学 ウイルス学 ウイルス学
- 遺伝学 遺伝学とは
背景:
- バクテリオファージのラムダ遺伝子Qタンパク質は,重要な陽性調節体です.
- Q遺伝子は,トランスクリプションアンチターミネーターとして機能し,特に遅い遺伝子プロモーターをターゲットにします.
研究 の 目的:
- ファグラムダ遺伝子Qタンパク質がRNAポリメラーゼと相互作用するメカニズムを解明する.
- 転写停止を克服するQタンパク質の役割を調査する.
- Qタンパク質の活性におけるNusaタンパク質の要件を決定する.
主な方法:
- In vitroトランスクリプションアッセイが実施されました.
- 研究は,Qタンパク質,RNAポリメラーゼ,およびファグ後期遺伝子プロモーターの相互作用に焦点を当てた.
- RNAポリメラーゼが16核酸で一時停止する際にQタンパク質が及ぼす効果を分析した.
主要な成果:
- Qタンパク質は,他のプロモーターではなく,ファグの遅い遺伝子プロモーターのRNAポリメラーゼと特異的に相互作用します.
- この相互作用は,RNAポリメラーゼが遅い遺伝子トランスクリプトの16個の核酸を合成した後,一時停止しているときに発生します.
- Qタンパク質は,停滞部位からRNAポリメラーゼの放出を促進し,その転写特性を変化させます.
- NusAタンパク質は,Qタンパク質の効率的な活性化に不可欠であることが in vitro で判明しました.
結論:
- RNAポリメラーゼのQタンパク質媒介による改変により,早期の停止部位から脱出することができます.
- この脱出メカニズムは,ポリメラーゼがターミネーターを通して転写することを可能にするために不可欠です.
- NusAタンパク質は,Qタンパク質のアンチターミネーション機能に必要なコファクターです.
さらに関連する動画
関連する概念動画
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...
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...
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:
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...
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)...

