The Functional Half-Life of an mRNA Depends on the Ribosome Spacing in an Early Coding Region

Publication: Research - peer-reviewJournal article – Annual report year: 2011

Without internal affiliation

  • Author: Pedersen, Margit

    Unknown

  • Author: Nissen, Søren

    University of Copenhagen2

  • Author: Mitarai, Namiko

    University of Copenhagen2

  • Author: Svenningsen, Sine Lo

    University of Copenhagen2

  • Author: Sneppen, Kim

    University of Copenhagen2

  • Author: Pedersen, Steen

    University of Copenhagen2

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Bacterial mRNAs are translated by closely spaced ribosomes and degraded from the 5′-end, with half-lives of around 2 min at 37 °C in most cases. Ribosome-free or “naked” mRNA is known to be readily degraded, but the initial event that inactivates the mRNA functionally has not been fully described. Here, we characterize a determinant of the functional stability of an mRNA, which is located in the early coding region. Using literature values for the mRNA half-lives of variant lacZ mRNAs in Escherichia coli, we modeled how the ribosome spacing is affected by the translation rate of the individual codons. When comparing the ribosome spacing at various segments of the mRNA to its functional half-life, we found a clear correlation between the functional mRNA half-life and the ribosome spacing in the mRNA region approximately between codon 20 and codon 45. From this finding, we predicted that inserts of slowly translated codons before codon 20 or after codon 45 should shorten or prolong, respectively, the functional mRNA half-life by altering the ribosome density in the important region. These predictions were tested on eight new lacZ variants, and their experimentally determined mRNA half-lives all supported the model. We thus suggest that translation-rate-mediated differences in the spacing between ribosomes in this early coding region is a parameter that determines the mRNAs functional half-life. We present a model that is in accordance with many earlier observations and that allows a prediction of the functional half-life of a given mRNA sequence.
Keyword: Gene expression,Ribosome spacing,mRNA functional half-life,Modeling
Original languageEnglish
JournalJournal of Molecular Biology
Publication date2011
Volume407
Issue1
Pages35-44
ISSN00222836
DOIs
StatePublished
CitationsWeb of Science® Times Cited: 4
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