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High-throughput Purification of Affinity-tagged Recombinant Proteins
Published on: August 26, 2012
ネズミの転写終結因子TTF IとクラスIRNAポリメラーゼの特異的な相互作用
Nature
|April 5, 1990
まとめ
転写終止因子 (TTF I) は,SalボックスでRNAポリメラーゼIの転写を特に停止する. このタンパク質は,
科学分野:
- 分子生物学は分子生物学である.
- 遺伝子規制 遺伝子規制
- バイオケミストリー バイオケミストリー
背景:
- リボソーム遺伝子の転写の終結は,細胞の恒常性にとって極めて重要です.
- サルボックス配列とTTF Iタンパク質は,マウスのリボソーム遺伝子の転写終了を媒介する.
- プライマリトランスクリプトのポストトランスクリプション処理には,配列依存のトリミングが含まれます.
研究 の 目的:
- TTFIがSalボックスに結合すると,RNAポリメラーゼのステリック阻害が生じるかどうかを調べる.
- 異なるRNAポリメラーゼによる転写延長を阻害するTTF Iの特異性を決定する.
主な方法:
- 精製されたTTF Iおよび様々なRNAポリメラーゼを用いたインビトロ転写アッセイ.
- マウスと酵母からRNAポリメラーゼIによる転写延長に対するTTFIの効果を試験する.
- TTF IがユカリオットRNAポリメラーゼII,III,バクテリア/ファージRNAポリメラーゼを含む異質ポリメラーゼに与える影響を評価する.
- TTF Iの効果と,ラック・レプレッサーの既知の抑制機能を比較した結果です.
主要な成果:
- TTF Iは,異なる種 (マウス,酵母) の間でRNAポリメラーゼIによって媒介された転写を特に終了します.
- TTF Iは,RNAポリメラーゼII,III,E. coli,またはバクテリオファージT3RNAポリメラーゼによる転写の延長を阻害しない.
- ラック・リプレッサーがそのオペレータ配列に結合すると,RNAポリメラーゼIとIIの両方の延長が抑制されます.
結論:
- 転写終結におけるTTF Iの機能は,RNAポリメラーゼIに特異的である.
- TTF Iは,一般的な延長阻害剤ではなく,特定の転写終止因子として作用します.
- TTF Iの特異性は,異なるDNA結合タンパク質による異なった転写調節機構を強調しています.
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...
Transcription Elongation Factors
Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not surprising that the elongation complex's composition also varies along the way while transcribing a gene.
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...
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:
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...
General Transcription Factors
Tissue-specific transcription factors contribute to diverse cellular functions in mammals. For example, the gene for beta globin, a major component of hemoglobin, is present in all cells of the body. However, it is only expressed in red blood cells because the transcription factors that can bind to the promoter sequences of the beta globin gene are only expressed in these cells. Tissue-specific transcription factors also ensure that mutations in these factors may impair only the function of...

