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The Effect of Cap Structure and Poly(A) Positioning on mRNA Translation Efficiency
Mizuki Tada1, Naoko Abe1, Masahito Inagaki1
1Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan.
Angewandte Chemie (International Ed. in English)
|October 13, 2025
Summary
Altering messenger RNA (mRNA) structure by swapping the 5' cap and 3' poly(A) tail significantly reduced translation efficiency. However, a 3' cap still enhanced translation, while a 5' poly(A) tail suppressed it.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Messenger RNA (mRNA) structure, including the 5' cap and 3' poly(A) tail, is crucial for gene expression.
- The precise roles and optimal positioning of these elements in translation remain areas of active investigation.
Purpose of the Study:
- To investigate the impact of interchanging the positions of the 5' cap and 3' poly(A) tail on mRNA translation efficiency.
- To elucidate the independent and combined effects of cap and poly(A) tail placement on protein synthesis.
Main Methods:
- Development of a novel chemical method for capping oligonucleotides.
- Purification of capped mRNAs using reversed-phase high-performance liquid chromatography (HPLC) with a photoreactive tag.
- Design and synthesis of mRNA constructs with inverted cap and poly(A) tail positions.
Main Results:
- Reversing the positions of the 5' cap and 3' poly(A) tail abolished synergistic translation enhancement, leading to significantly reduced activity.
- A 3' cap structure, while less effective than a 5' cap, still conferred a measurable increase in translation.
- A 5' poly(A) tail was found to suppress translation efficiency.
- An inverted 3'-5' oriented poly(A) tail retained its ability to enhance protein synthesis.
Conclusions:
- The canonical 5' cap and 3' poly(A) tail orientation is optimal for synergistic translation enhancement.
- Both cap and poly(A) tail elements influence translation, but their positionality and orientation are critical for function.
- Understanding mRNA structural requirements provides insights into gene regulation and potential therapeutic strategies.
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