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Updated: Jul 15, 2025
05:37
Single-Molecule Fluorescence Visualization of DNA Polymerase Dynamics at G-Quadruplexes
Published on: April 4, 2025
718
5'UTR G-quadruplex structure enhances translation in size dependent manner
Sua Myong1, Chun-Ying Lee1, Meera Joshi1
1Boston Children's Hospital/Harvard Medical School.
Research Square
|October 4, 2023
Summary
G-quadruplexes (G4) in mRNA 5' untranslated regions significantly boost bacterial translation efficiency. This effect, enhanced by upstream hairpins, suggests a physical barrier mechanism for gene expression regulation.
Area of Science:
- Molecular Biology
- Biophysics
- Genetics
Background:
- Bacterial translation initiation is often controlled by structures within the 5' untranslated region (5'UTR).
- G-quadruplex (G4) structures in DNA have been shown to enhance transcription.
Approach:
- Investigated the impact of mRNA G-quadruplex (RG4) formation in the 5'UTR on translation.
- Utilized a T7-based in vitro translation system and experiments in *E. coli*.
- Assessed the influence of RG4 size and the effect of an upstream hairpin structure.
Key Points:
- RG4 formation in the 5'UTR strongly and size-dependently promotes translation efficiency.
- An upstream hairpin combined with RG4 can increase translation efficiency up to 12-fold.
- The RG4 effect is independent of changes in ribosome affinity, binding site accessibility, or mRNA stability.
Conclusions:
- Proposed a physical barrier model where bulky 5'UTR structures impede ribosome dislodging, enhancing translation output.
- Provides biophysical insights into the regulatory roles of 5'UTR structures in bacterial translation.
- Highlights the potential of RG4 structures for tuning gene expression in bacteria.
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