小组报道了一种甲基转移酶OVERACHIEVER，它使25S核糖体RNA （rRNA）的肽基转移酶中心甲基化。残基m3U2952促进功能性tSpm与肽基转移酶中心连接P-位点转移RNA （tRNA）和rRNA残基的特定位点结合。这种相互作用增强了SACLs的翻译，抑制了LHW的翻译。他们的研究揭示了保守的rRNA碱基甲基化和多胺在协调细胞命运决定中的依赖关系，强调了核糖体化学景观在翻译调节中的作用。
研究人员表示，多胺常与核糖体结合，被认为能稳定核糖体的完整性。在拟南芥中，多胺热精胺（tSpm）影响木质部细胞命运。tSpm诱导抑制ACAULIS51（SAC51）及其同系物的翻译，从而抑制木质部发育蛋白LONESOME-HIGHWAY （LHW）和TARGET-OF-MONOPTEROS5的异源二聚化。
附：英文原文
Title: Recruitment of bifunctional regulator thermospermine to methylated ribosomes directs xylem fate
Author: 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 avar Zeljkovi, Tine Drud Lundager Rasmussen, Ondrej Novak, Zsuzsanna Bodi, Gugan Eswaran, Brecht Wybouw, Matthieu Bourdon, Cristina Urbez, Xiaonan Liu, Kari Salokas, Tiina hman, Tanya Waldie, Petri Trnen, 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. Blazquez, Liisa Holm, Rupert Fray, Markku Varjosalo, Ottoline Leyser, Ville O. Paavilainen, Ari Pekka Mhnen, Anna Stepanova, Jose Alonso, Steffen Heber, Robert Malinowski, Finn Kirpekar, Alan J. Warren, Yk Helariutta
Issue&Volume: 2026-02-12
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.
DOI: adx2867
Source: https://www.science.org/doi/10.1126/science.adx2867