80S モノソームの翻訳状態の再定義
Erin E Heyer1, Melissa J Moore1
1Howard Hughes Medical Institute, RNA Therapeutics Institute and Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Cell
|February 13, 2016
まとめ
モノソームだけでなくポリソームも イーストのmRNAを活性化します このリボソーム群は,ナンセンス媒介性衰退 (NMD) の標的であるものを含む特定のmRNAの翻訳を調節するために重要である.
科学分野:
- 分子生物学
- 遺伝学
- 生物化学
背景:
- リボソームはモノソームとポリソームとして存在し,ポリソームは広く研究されている.
- モノソームにおける翻訳の役割と範囲は論争の的であり,あまり理解されていない.
- モノソームの機能を理解することは 細胞のタンパク質合成の完全なイメージの鍵です
研究 の 目的:
- Saccharomyces cerevisiaeにおける80Sモノソームの翻訳的活動と重要性を調査する.
- モノソームプール内のリボソームの開始と延長の比率を決定する.
- モノソーム占有率に関連するmRNA特性を特定する.
主な方法:
- 80Sモノソームのトランスレーション状態を分析するためにリボソームプロファイリングを使用した.
- 異なるmRNA集団における量化されたリボソーム占有率.
- 特定のmRNA特性と規制的な役割を持つ相関したモノソーム濃縮.
主要な成果:
- 80Sモノソームの大多数は,翻訳を開始せず,活発に伸びていることが判明した.
- ほとんどのmRNAは,無意味媒介の衰退 (NMD) ターゲットと上流のオープン・リーディング・フレーム (uORF) にある程度のモノソーム占有を示した.
- モノソームは,より短いORFと,開始時間に対してより速く伸びるもの,特に低多量調節タンパク質をコードするものは,優位であった.
結論:
- モノソームは,全体的な翻訳的な出力において,重要で,しばしば過小評価される役割を果たします.
- モノソーム占有は,特定のmRNAサブセット,NMDターゲットおよび規制タンパク質のmRNAを含む重要な規制メカニズムです.
- これらの発見は,翻訳による遺伝子発現の正確な規制におけるモノソームの重要性を強調しています.
関連する概念動画
02:24Ribosome Profiling
4.3K
Ribosome profiling or ribo-sequencing is a deep sequencing technique that produces a snapshot of active translation in a cell. It selectively sequences the mRNAs protected by ribosomes to get an insight into a cell’s translation landscape at any given point in time.
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique...
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique...
4.3K
01:29Translational Regulation
799
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,...
799
01:20Cotranslational Protein Translocation
10.9K
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
10.9K
01:29Translation in Prokaryotes
2.4K
Prokaryote translation is a complex, highly coordinated process that converts genetic information from mRNA into functional proteins. It involves three stages: initiation, elongation, and termination, each facilitated by specific molecular components.Initiation of TranslationThe process begins with the assembly of the ribosomal subunits and initiation factors on the mRNA. In bacteria, the 30S ribosomal subunit recognizes the Shine-Dalgarno sequence in the mRNA, a conserved region upstream of...
2.4K
01:44Termination of Translation
28.5K
The large ribosomal subunit has several important structures essential to translation. These include the peptidyl transferase center (PTC) - which is the site where the peptide bond is formed - and a large, internal, water-filled tube through which the nascent polypeptide moves. This latter structure is called the Peptide Exit Tunnel, and it begins at the PTC and spans the body of the large ribosomal subunit. During translation, as the nascent polypeptide chain is synthesized, it passes through...
28.5K
02:07Improving Translational Accuracy
15.4K
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...
15.4K