m1A58 acts as a conformational checkpoint coupling human initiator tRNA maturation to translation initiation
- 1ShanghaiTech University
Abstract
tRNAs are characterized by extensive chemical modifications that influence tRNA fate. N1-methyladenosine at position 58 (m1A58) is a widespread core tRNA modification linked to physiological and pathological processes. However, how m1A58 coordinate tRNA folding and processing to ensure translational efficiency in mammalian cells remains largely unknown. Using acute dTAG-mediated degradation and CRISPR-Cas9 knockout, we identified initiator methionine tRNA (tRNAiMet) as selectively vulnerable to m1A58 loss, lacking the isodecoder buffering observed for most other tRNA isoacceptors. NMR analysis of the tRNAiMet showed that m1A58 stabilizes D/T-loop interactions, consistent with a maturation-competent conformation. In vitro processing assays further demonstrated that m1A58 promotes RNase P-mediated 5'-leader removal and RNase Z-mediated 3'-trailer cleavage, while La/SSB protects accumulated precursors. Disrupting this checkpoint impaired the assembly of the eIF2-containing 43S pre-initiation complex and global protein synthesis, which was substantially rescued by adding m1A58-modified tRNAiMet. Acute TRMT6 degradation elicited temporally coordinated gene-expression responses involving proteostasis, transport and signaling. Together, these findings establish m1A58 as a conformational checkpoint coupling human initiator-tRNA maturation to translation initiation and stress responses.
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BibTeX
@misc{liu2026m1a58,
title = {{m1A58 acts as a conformational checkpoint coupling human initiator tRNA maturation to translation initiation}},
author = {R.-J. Liu and H. Li and X.-Y. Wu and Y.-J. Zhou and M.-J. Yared and C.-X. Wang and P.-Y. Tian and Q.-Y. Liu and Z.-G. Bao and P. Barraud},
howpublished = {bioRxiv},
year = {2026},
month = aug,
doi = {10.64898/2026.08.28.747798},
url = {https://www.biorxiv.org/content/10.64898/2026.08.28.747798v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - m1A58 acts as a conformational checkpoint coupling human initiator tRNA maturation to translation initiation
AU - R.-J. Liu
AU - H. Li
AU - X.-Y. Wu
AU - Y.-J. Zhou
AU - M.-J. Yared
AU - C.-X. Wang
AU - P.-Y. Tian
AU - Q.-Y. Liu
AU - Z.-G. Bao
AU - P. Barraud
PY - 2026
DA - 2026/08/28
PB - bioRxiv
DO - 10.64898/2026.08.28.747798
UR - https://www.biorxiv.org/content/10.64898/2026.08.28.747798v1
AB - tRNAs are characterized by extensive chemical modifications that influence tRNA fate. N1-methyladenosine at position 58 (m1A58) is a widespread core tRNA modification linked to physiological and pathological processes. However, how m1A58 coordinate tRNA folding and processing to ensure translational efficiency in mammalian cells remains largely unknown. Using acute dTAG-mediated degradation and CRISPR-Cas9 knockout, we identified initiator methionine tRNA (tRNAiMet) as selectively vulnerable to m1A58 loss, lacking the isodecoder buffering observed for most other tRNA isoacceptors. NMR analysis of the tRNAiMet showed that m1A58 stabilizes D/T-loop interactions, consistent with a maturation-competent conformation. In vitro processing assays further demonstrated that m1A58 promotes RNase P-mediated 5'-leader removal and RNase Z-mediated 3'-trailer cleavage, while La/SSB protects accumulated precursors. Disrupting this checkpoint impaired the assembly of the eIF2-containing 43S pre-initiation complex and global protein synthesis, which was substantially rescued by adding m1A58-modified tRNAiMet. Acute TRMT6 degradation elicited temporally coordinated gene-expression responses involving proteostasis, transport and signaling. Together, these findings establish m1A58 as a conformational checkpoint coupling human initiator-tRNA maturation to translation initiation and stress responses.
ER -