まとめ
Xenopus 5SのRNA合成の終了には,DNAにT残基のクラスターが必要です. 開始と終了のためのシーケンス信号は分離可能であり,独立して機能し,GCが豊富な領域が効率性を高めます.
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:
- 正確な転写終結は,遺伝子調節に極めて重要です.
- Xenopus 5S RNA遺伝子のような真核生物の終止信号を理解することは不可欠です.
研究 の 目的:
- Xenopus 5SのRNA合成を終了させるDNA配列を in vitroで特定し,特徴づけること.
- 始動信号と終止信号の関係を見極めるため.
主な方法:
- XenopusのDNA配列を用いた in vitroトランスクリプションアッセイ.
- 終末部位を取り囲むDNA配列の分析.
主要な成果:
- 終結は,コード化されていないDNA鎖の4つまたはそれ以上の連続したT残基のクラスターで発生します.
- 開始と終了のシーケンス信号は分離可能で独立しています.
- Tクラスターに隣接するGC豊富な配列は,終了効率を高めます.
- Tクラスターの近くの連続したA残留は,終了効率を低下させる.
結論:
- Xenopus 5S RNAの遺伝子終結は,主にT豊富な配列によって決定されます.
- 終止効率は,側面の配列と環境要因によって調節されます.
- ユカリオットの終結信号は,重要な二酸化対称性が欠け,プロカリオットと異なる.
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...
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)...


