関連する実験動画
Updated: Aug 18, 2026

10:37
Toeprinting Analysis of Translation Initiation Complex Formation on Mammalian mRNAs
Published on: May 10, 2018
ユカリオトのリボソームは,イニシアーションコドンを見つけ出すために,イニシアーション因子1と1Aを必要とします
T V Pestova1, S I Borukhov, C U Hellen
1Department of Microbiology and Immunology, State University of New York Health Science Center at Brooklyn, 11203, USA. tpestova@netmail.hscbklyn.edu
Nature
|September 11, 1998
まとめ
2つの重要な翻訳開始因子,eIF1とeIF1Aは,真核リボソームがメッセンジャーRNAのスタートコドンを発見するために不可欠です. その欠如は,適切な複合体の組み立てを妨げ,タンパク質合成の開始を妨げます.
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:
- スキャニングモデルは,mRNA 5' cap. でのユーカリオット翻訳開始を説明しています.
- 以前に,リボソームスキャンには5つのエウカリオット発起因子 (eIF) が十分と考えられていた.
研究 の 目的:
- 翻訳開始におけるeIF1とeIF1Aの役割を調査する.
- リボソームスキャニングに追加のeIFが必須かどうかを初期コドンに決定する.
主な方法:
- 精製されたリボソーム前始動複合体を用いたインビトロ検査.
- ATPと特定のエウカリオット発起因子 (eIFs) のインキュベーション.
- リボソーム複合体の形成とmRNAの局所化の分析.
主要な成果:
- eIF1とeIF1Aは,翻訳の開始に不可欠であることが判明しました.
- eIF1とeIF1Aがなければ,43S複合体はmRNAのキャップ・プロキシマル領域に結合するが,イニシアチブ・コドンに到達することができない.
- eIF1Aはキャップ・プロキシマル複合体の形成を促進し,eIF1は開始コドンで48S複合体の形成を促進する.
結論:
- eIF1とeIF1Aは,mRNAのイニシアチブコドンで適切なリボソーム複合体の組み立てを確保するために,連携して作用します.
- これらの要因は,異常複合体を解離し,正確な翻訳開始を確保するために重要である.
関連する概念動画
Ribosomal RNA Synthesis
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
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...
Leaky Scanning
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 stands for...
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...
Translation in Prokaryotes
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...

