E. coli trpR遺伝子の発現におけるフレームシフトは,そのコード配列のセグメントをバイパスすることによって発生します
1Department of Molecular Biology, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
Cell
|January 15, 1993
まとめ
E. coliにおける新しい遺伝子発現メカニズムは,タンパク質合成中に特定のmRNAセグメントがスキップされる翻訳バイパスを含む. このプロセスは,trpR遺伝子の発現に不可欠であり,翻訳性イントロンの潜在的な存在を示唆しています.
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
- 微生物学 微生物学とは
背景:
- Escherichia coli (E. coli) のtrpR遺伝子は,trp抑制タンパク質をコードする.
- 以前の研究では,trpR遺伝子の発現中に+1のフレームシフトイベントが確認されました.
研究 の 目的:
- E. coli trpR遺伝子発現における+1フレームシフトイベントのメカニズムを解明する.
- 翻訳的なフレームシフトにおけるmRNA配列と構造の役割を調査する.
主な方法:
- trpR+1-lacZ mRNAコンストラクタの分析.
- 翻訳バイパスの要件を調査する.
- 特定のmRNA配列と上流領域の役割を研究する.
主要な成果:
- trpR発現における0から+1の読み取りフレームへの移行は,55核酸 (nt) のmRNAセグメントをバイパスすることで起こります.
- このバイパスイベントは,その前にではなく,翻訳中に起こります.
- 2つの隣接する要素が必要である:特定のtrpR配列と,10以上の翻訳可能なコードンの前の非特異的な5'端.
- 55-nt領域はフレーム0に変換され, +1フレームへのバイパスが容易になります.
結論:
- 翻訳バイパスは,遺伝子発現の新たに特定されたメカニズムです.
- この発見は,スプレイスソーマのイントロンに類似した,トランスレーション性イントロンの潜在的な存在を示唆しています.
- このメカニズムは,プロカリオットの遺伝子発現の調節に関する新しい洞察を提供します.
関連する概念動画
02:42Transcription Attenuation in Prokaryotes
14.6K
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...
14.6K
02:28Leaky Scanning
4.5K
During most eukaryotic translation processes, the small 40S ribosome subunit scans an mRNA from its 5' end until it encounters the first start AUG codon. The large 60S ribosomal subunit then joins the smaller one to initiate protein synthesis. The location of the translation initiation is largely determined by the nucleotides near the start codon as there may be multiple translation initiation sites present on the mRNA. Marilyn Kozak discovered that the sequence RCCAUGG (where R...
4.5K
02:11Reporter Genes
11.4K
Reporter genes are a type of protein-coding gene that are often tagged to a gene of interest. Once inside a target cell, reporter genes usually produce visually identifiable characteristics like fluorescence and luminescence when expressed along with the gene of interest. Thus, reporter genes “report” the presence or absence of genes of interest in an organism, determine the gene expression pattern, or track the physical location of a DNA segment or protein in the cell.
11.4K
01:29Coordination of Gene Expression Processes in Bacteria
1.1K
The DNA replication, transcription, and translation processes are intricately coupled in bacteria, allowing efficient gene expression and rapid protein synthesis. While this physical and functional coordination is advantageous, it introduces challenges that bacteria overcome through specific regulatory mechanisms.Coupling of Replication, Transcription, and TranslationThe coupling of replication, transcription, and translation is a hallmark of bacterial gene expression. As the replisome unwinds...
1.1K
01:21Repressible Operon: trp Operon
2.8K
The trp operon in Escherichia coli exemplifies a repressible operon. It regulates the synthesis of tryptophan through repressor-mediated transcriptional control and attenuation. This dual regulatory mechanism ensures tryptophan biosynthesis occurs only when needed, conserving cellular resources.Structure of the trp OperonThe trp operon consists of five structural genes (trpE, trpD, trpC, trpB, and trpA) that encode enzymes for tryptophan biosynthesis. These genes are transcribed as a single...
2.8K
01:23Stringent Response in E. coli
533
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
533