Evolutionarily reinforced GC-rich motif enables non-AUG translation in mammals under eIF1/5MP-mediated fidelity control
Non-AUG translation contributes to proteome diversity, but its regulatory principles remain unclear. Here, we show that a GCC-rich upstream extension, termed the NAT1 motif, acts as a potent enhancer of near-cognate initiation in mammals. Cell-free and reporter assays revealed that eIF1 and 5MP act as conserved inhibitors of non-AUG initiation across mammals and plants, while the NAT1 motif enables enhanced initiation within this fidelity framework. Mutational analysis identified −6 and −7 positions within the GCC repeat as key determinants of motif activity. Genome-wide analyses uncovered evolutionary depletion of NAT1 -type non-AUG codons in human 5′UTRs, suggesting purifying selection against excessive initiation. Nevertheless, more than a hundred retained sites are associated with genes involved in cell proliferation and migration, suggesting that regulated non-AUG initiation may contribute to disease-relevant translational programs. The motif’s enrichment within GCC repeats further suggests a mechanistic link to repeat-associated non-AUG translation.
Authors
- Grant Brooke (ORCID: https://orcid.org/0009-0004-4027-8143)
- Toshinobu Fujiwara (ORCID: https://orcid.org/0000-0001-6952-162X)
- Katsura Asano (ORCID: https://orcid.org/0000-0002-8636-0263)
- Chingakham Ranjit Singh (ORCID: https://orcid.org/0000-0003-2840-3066)
- Yuichi Togashi (ORCID: https://orcid.org/0000-0003-0032-2424)
- Hiroyuki Hiraishi
- Takeru Kameda (ORCID: https://orcid.org/0000-0002-7621-4289)
- 八木瞳
- Nirmala Bardiya
- Haruyuki Furukawa (ORCID: https://orcid.org/0009-0007-6022-4056)
- Susumu Ishiguro (ORCID: https://orcid.org/0000-0002-3268-7754)
- Franck Martin (ORCID: https://orcid.org/0000-0001-9724-4025)
- Hiroaki Kato (ORCID: https://orcid.org/0000-0001-9591-1875)
- Kazuyuki Takai (ORCID: https://orcid.org/0000-0001-7096-0312)
- Antonin Tidu (ORCID: https://orcid.org/0009-0004-0358-0490)
- Abhineet Banerjee
- Anastasia Meyer
- Grace Sakai
- Kinsley Ochsner
- Antoine Perret (ORCID: https://orcid.org/0009-0008-9306-5554)
- Keat Robinson
- Payton Henderson
- Megan Freeman
- Hailey Casey
- William Finnane (ORCID: https://orcid.org/0009-0007-8763-9892)
Institutions
- Hiroshima University (JP)
- Centre National de la Recherche Scientifique (FR)
- Ritsumeikan University (JP)
- Shimane University (JP)
- Kansas State University (US)
- Architecture et Réactivité de l'arN (FR)
- Ehime University (JP)
- Kindai University (JP)
Publication Details
- Journal
- Science Advances
- Published
- 2026-11-11
- DOI
- https://doi.org/10.1126/sciadv.aek4290
- Primary Topic
- RNA and protein synthesis mechanisms
- Type
- article
- Field-Weighted Citation Impact
- 0.00