ユカリオットリボソームによる翻訳制御.
Ivan Topisirovic1, Nahum Sonenberg
1Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada. ivan.topisirovic@mcgill.ca
Cell
|May 3, 2011
まとめ
マウスにおけるリボソームタンパク質L38の喪失は,選択的にHox mRNA翻訳を減少させます. これは,リボソームタンパク質が胚の発達に不可欠であり,この重要な段階で遺伝子発現に影響を及ぼすことを示唆しています.
科学分野:
- 分子生物学は分子生物学である.
- 発達生物学 発達生物学について
- 遺伝学 遺伝学とは
背景:
- リボソームは,生命のあらゆる領域におけるタンパク質合成を担う不可欠な分子機構である.
- 個々のリボソームタンパク質が遺伝子発現を調節する正確な役割は,特に発達の過程では,完全に理解されていません.
研究 の 目的:
- ネズミの胚発達中のリボソームタンパク質L38機能喪失の機能的影響を調査する.
- リボソームタンパク質L38が,ホックスmRNAsなどの特定のmRNA標的の翻訳に影響を与えるかどうかを決定する.
主な方法:
- リボソームタンパク質L38.8をコードする遺伝子の機能喪失変異を有するマウスモデルを使用した.
- ホックスmRNAを含む様々なmRNAの翻訳効率を野生型と変異型マウスの間で測定し,比較する技術を用いる.
主要な成果:
- 機能的なリボソームタンパク質L38が欠けていたマウスは,ホックスmRNAsの翻訳の選択的減少を示した.
- このHox mRNA翻訳の減少は,発達異常と関連していました.
結論:
- リボソームタンパク質L38は,ホックスmRNAsの翻訳を調節する上で決定的で選択的な役割を果たします.
- これらの発見は,タンパク質合成の正確な制御を通じて,胚の発達における特定のリボソームタンパク質の重要な関与を強調しています.
関連する概念動画
Improving Translational Accuracy
Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
Initiation of Translation
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
Regulation of Expression Occurs at Multiple Steps
Gene expression can be regulated at almost every step from gene to protein. Transcription is the step that is most commonly regulated. This involves the binding of proteins to short regulatory sequences on the DNA. This association can either promote or inhibit the transcription of a gene associated with the respective sequence.
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Transcription results in the generation of precursor (pre-mRNA) that consists of both exons and introns, which needs further processing before being translated to a...
Initiation of Translation
Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
Regulation of Expression at Multiple Steps
The gene expression in cells is regulated at different stages: (i) transcription, (ii) RNA processing, (iii) RNA localization, and (iv) translation. Transcriptional regulation is mediated by regulatory proteins such as transcription factors, activators, or repressors—these control gene expression by initiating or inhibiting the transcription of genes. Once a precursor or pre-mRNA is produced, it undergoes post-transcriptional modification, including 5' capping, splicing, and the addition of a...
Translational Regulation
Translational regulation in prokaryotes ensures efficient protein synthesis by controlling ribosome access to mRNA. This regulation is mediated by secondary RNA structures, including translational riboswitches, RNA thermometers, and small RNAs (sRNAs), which respond to intracellular and environmental signals to modulate gene expression.Translational RiboswitchesRiboswitches in the leader region of mRNAs can regulate translation by altering the accessibility of the Shine-Dalgarno (SD) sequence,...


