An in vitro single-molecule assay for eukaryotic cap-dependent translation initiation kinetics Journal Article


Authors: Wang, H.; Sun, L.; Gaba, A.; Qu, X.
Article Title: An in vitro single-molecule assay for eukaryotic cap-dependent translation initiation kinetics
Abstract: Eukaryotic mRNAs are predominantly translated via the cap-dependent pathway. Initiation is a rate-limiting step in cap-dependent translation and is the main target of translational control mechanisms. There is a lack of high-resolution techniques for characterizing the cap-dependent initiation kinetics. Here, we report an in vitro single-molecule assay that allows characterization of both initiation and peptide chain elongation kinetics for cap-dependent translation. Surprisingly, the histogram of the first-round initiation time is highly asymmetrical and spans a large time range that is several-fold greater than the average peptide synthesis time in translation reactions with a firefly luciferase-encoding mRNA. Both the histogram and single-molecule trajectories reveal an unexpected high-degree of asynchrony in translation activity between mRNA molecules. Furthermore, by inserting a small stem-loop (ΔG = -4.8 kcal/mol) in the middle of the mRNA 5' untranslated region (UTR), our assay robustly detects small changes in budding yeast initiation kinetics, which could not be resolved by bulk luminescence kinetics. Lastly, we demonstrate the general applicability of this assay to distinct cell-free translation systems by using extracts prepared from budding yeast, wheat germ, and rabbit reticulocyte lysates. This assay should facilitate mechanistic studies of eukaryotic cap-dependent translation initiation and translational control. © The Author(s) 2019. Published by Oxford University Press on behalf of Nucleic Acids Research.
Journal Title: Nucleic Acids Research
Volume: 48
Issue: 1
ISSN: 0305-1048
Publisher: Oxford University Press  
Date Published: 2020-01-10
Start Page: e6
Language: English
DOI: 10.1093/nar/gkz1066
PUBMED: 31722415
PROVIDER: scopus
PMCID: PMC7145701
DOI/URL:
Notes: Source: Scopus
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  1. Xiaohui Qu
    7 Qu
  2. Hongyun Wang
    8 Wang
  3. Anthony Gaba
    5 Gaba
  4. Lexi Sun
    3 Sun