Recruitment of bifunctional regulator thermospermine to methylated ribosomes directs xylem fate

Recruitment of bifunctional regulator thermospermine to methylated ribosomes directs xylem fate. Ko, D., Ruonala, R., Faille, A., Hellmann, E., Help, H., Liu, H., Nielsen, R., Haakonsson, A., De Diego, N., Paatero, A., Shcherbii, M. V., Stefanowicz, K., Ćavar Zeljković, S., Drud Lundager Rasmussen, T., Novak, O., Bodi, Z., Eswaran, G., Wybouw, B., Bourdon, M., Urbez, C., Liu, X., Salokas, K., Öhman, T., Waldie, T., Törönen, P., el-Showk , S., Balcerowicz, M., Besnard, F., Liu, X., Perkins, P., Mazzoni-Putman, S., Vainonen, J. P., Sierla, M., Frilander, M. J., Mandrup, S., Vernoux, T., Ljung, K., Ferrando, A., Blazquez, M. A., Holm, L., Fray, R., Varjosalo, M., Leyser, O., Paavilainen, V. O., Mähönen, A. P., Stepanova, A., Alonso, J., Heber, S., Malinowski, R., Kirpekar, F., Warren, A. J., & Helariutta, Y. Science, 391(6786):694–699, American Association for the Advancement of Science, February, 2026.

Paper doi abstract bibtex

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 25S ribosomal RNA (rRNA). Residue m3U2952 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.

@article{ko_recruitment_2026,
	title = {Recruitment of bifunctional regulator thermospermine to methylated ribosomes directs xylem fate},
	volume = {391},
	url = {https://www.science.org/doi/10.1126/science.adx2867},
	doi = {10.1126/science.adx2867},
	abstract = {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 25S ribosomal RNA (rRNA). Residue m3U2952 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.},
	number = {6786},
	urldate = {2026-02-20},
	journal = {Science},
	publisher = {American Association for the Advancement of Science},
	author = {Ko, Donghwi and Ruonala, Raili and Faille, Alexandre and Hellmann, Eva and Help, Hanna and Liu, Huili and Nielsen, Ronni and Haakonsson, Anders and De Diego, Nuria and Paatero, Anja and Shcherbii, Mariia V. and Stefanowicz, Karolina and Ćavar Zeljković, Sanja and Drud Lundager Rasmussen, Tine and Novak, Ondrej and Bodi, Zsuzsanna and Eswaran, Gugan and Wybouw, Brecht and Bourdon, Matthieu and Urbez, Cristina and Liu, Xiaonan and Salokas, Kari and Öhman, Tiina and Waldie, Tanya and Törönen, Petri and el-Showk, Sedeer and Balcerowicz, Martin and Besnard, Fabrice and Liu, Xiaomin and Perkins, Patrick and Mazzoni-Putman, Serina and Vainonen, Julia P. and Sierla, Maija and Frilander, Mikko J. and Mandrup, Susanne and Vernoux, Teva and Ljung, Karin and Ferrando, Alejandro and Blazquez, Miguel A. and Holm, Liisa and Fray, Rupert and Varjosalo, Markku and Leyser, Ottoline and Paavilainen, Ville O. and Mähönen, Ari Pekka and Stepanova, Anna and Alonso, Jose and Heber, Steffen and Malinowski, Robert and Kirpekar, Finn and Warren, Alan J. and Helariutta, Ykä},
	month = feb,
	year = {2026},
	pages = {694--699},
}

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