Download MendeleyStructural and molecular basis of specialized translation mediated by the ribosome mRNA-binding channel.
Fraticelli, D., Hiregange, D.G., Weiss, B., Ogran, A., Havkin-Solomon, T., Roman, I.M., Bashan, A., Yonath, A., Dikstein, R.(2026) Nat Commun
- PubMed: 42056121 Search on PubMed
- DOI: https://doi.org/10.1038/s41467-026-72263-5
- Primary Citation Related Structures:
9RU7, 9RUC - PubMed Abstract:
The ribosome mRNA channel is central to translation, yet its role in regulatory mechanisms remains unclear. Using cryo-EM of human ribosomal complexes bound to Kozak and TISU mRNAs from wild-type (WT) and RPS26/eS26 mutant (RPS26dC) cells, we demonstrate that both RPS26/eS26 and mRNA adopt distinct conformations, explaining the opposing effects of RPS26dC on their activity. Translatome studies of WT and RPS26dC reveal AUG-context-dependent changes in 48S and 80S initiation complexes and slower scanning. Downregulated mRNAs are enriched for specific AUG-upstream nucleotides and a -1-cytosine contacting 18S rRNA G1207, an interaction lost in RPS26dC. Strongly affected transcripts include replication-dependent histones, which, despite short 5'UTRs and suboptimal Kozak, exhibit robust translation activity that is RPS26/eS26-dependent. We identify a translational enhancer in the H2B 5'UTR (-16 to -9) overlapping predicted RPS26/eS26-binding sites, with a distinct ribosome-bound conformation. Exploiting these features, we engineered a high-efficiency translational cassette with minimal leaky scanning. These findings underscore the role of the ribosome's mRNA channel in selective translation and its therapeutic potential.
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel.
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