Recruitment of bifunctional regulator thermospermine to methylated ribosomes directs xylem fate
- Donghwi Ko
- Raili Ruonala
- Alexandre Faille
- Eva Hellmann
- Hanna Help
- Huili Liu
- Ronni Nielsen
- Anders Haakonsson
- Nuria De Diego
- Anja Paatero
- Mariia V. Shcherbii
- Karolina Stefanowicz
- Sanja Ćavar Zeljković
- Tine Drud Lundager Rasmussen
- Ondřej Novák
- Zsuzsanna Bodi
- Gugan Eswaran
- Brecht Wybouw
- Matthieu Bourdon
- Cristina Úrbez
- Xiaonan Liu
- Kari Salokas
- Tiina Öhman
- Tanya Waldie
- Petri Törönen
- Sedeer el-Showk
- Martin Balcerowicz
- Fabrice Besnard
- Xiaomin Liu
- Patrick Perkins
- Serina Mazzoni-Putman
- Julia P. Vainonen
- Maija Sierla
- Mikko J. Frilander
- Susanne Mandrup
- Teva Vernoux
- Karin Ljung
- Alejandro Ferrando
- Miguel A. Blázquez
- Liisa Holm
- Rupert Fray
- Markku Varjosalo
- Ottoline Leyser
- Ville O. Paavilainen
- Ari Pekka Mähönen
- Anna Stepanova
- Jose Alonso
- Steffen Heber
- Robert Malinowski
- Finn Kirpekar
2026-02-12
Polyamines are often associated with ribosomes and are thought to stabilize their integrity. In Arabidopsis , the polyamine thermospermine (tSpm) affects xylem cell fate. tSpm induces translation of SUPPRESSOR-OF-ACAULIS51 (SAC51) and SAC51-LIKEs (SACLs), which inhibit heterodimerization of the xylem development proteins LONESOME-HIGHWAY (LHW) and TARGET-OF-MONOPTEROS5. Here, we report a methyltransferase, OVERACHIEVER, that methylates the peptidyl transferase center of the 25 S ribosomal RNA (rRNA). Residue m 3 U2952 promotes functional tSpm binding to a specific site connecting the P-site transfer RNA (tRNA) with rRNA residues in the peptidyl transferase center. This interaction enhances the translation of SACLs but inhibits that of LHW. Our study uncovers the dependency between a conserved rRNA base methylation and a polyamine in orchestrating cell fate decisions, highlighting a role for the ribosome chemical landscape in translational regulation.