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Updated: Jun 26, 2026
10:37
Toeprinting Analysis of Translation Initiation Complex Formation on Mammalian mRNAs
Published on: May 10, 2018
Small RNA binding to 5' mRNA coding region inhibits translational initiation
Marie Bouvier1, Cynthia M Sharma, Franziska Mika
1Max Planck Institute for Infection Biology, RNA Biology Group, Berlin D-10117, Germany.
Molecular Cell
|December 30, 2008
Summary
Small noncoding RNAs (sRNAs) can repress bacterial translation by binding to the 5' coding region of mRNA, not just the start codon. This mechanism expands understanding of sRNA regulatory roles and target identification.
Area of Science:
- Bacteriology
- Molecular Biology
- RNA Biology
Background:
- Small noncoding RNAs (sRNAs) primarily repress bacterial mRNA translation by blocking ribosome binding at the Shine-Dalgarno (SD) or AUG start codon.
- Recent discoveries show sRNAs lacking SD/AUG complementarity, suggesting alternative repression mechanisms.
Purpose of the Study:
- To investigate the mechanism of Salmonella RybB sRNA repression of ompN mRNA.
- To explore if sRNAs can repress translation without direct interaction with SD or AUG sequences.
Main Methods:
- Systematic antisense interference assays were used to analyze 30S ribosome binding to ompN mRNA and other mRNAs.
- Investigated the role of the 5' coding region in sRNA-mediated translational control.
Main Results:
- Salmonella RybB sRNA represses ompN mRNA translation by binding to its 5' coding region.
- sRNAs can sequester mRNA sequences up to the fifth codon, inhibiting translation initiation independently of SD/AUG pairing.
- This mechanism was observed for both ompN and unrelated mRNAs.
Conclusions:
- sRNAs can function as translational repressors by targeting sequences within the 5' coding region of mRNA, beyond the traditional SD/AUG sites.
- A "five codon window" in the 5' coding region is identified as a potential site for sRNA-mediated translational control.
- Findings impact sRNA target prediction strategies and suggest applicability to other cis-regulatory elements like RNA thermosensors and riboswitches.
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