Upregulation of RNA cap methyltransferase RNMT drives ribosome biogenesis during T cell activation. Issue 12 (14th June 2021)

• Record Type: Journal Article
• Authors: Galloway, Alison; Kaskar, Aneesa; Ditsova, Dimitrinka; Atrih, Abdelmadjid; Yoshikawa, Harunori; Gomez-Moreira, Carolina; Suska, Olga; Warminski, Marcin; Grzela, Renata; Lamond, Angus I; Darzynkiewicz, Edward; Jemielity, Jacek; Cowling, Victoria H
• Is Part Of: Nucleic acids research. Volume 49:Issue 12(2021)
• Page Start: 6722
• Page End: 6738
• Publication Date: 2021-06-14
• Subjects: Nucleic acids -- Periodicals; Molecular biology -- Periodicals; 572.805
• DOI: 10.1093/nar/gkab465
• Languages: English
• ISSNs: 0305-1048

Abstract

Abstract: The m7 G cap is ubiquitous on RNAPII-transcribed RNA and has fundamental roles in eukaryotic gene expression, however its in vivo role in mammals has remained unknown. Here, we identified the m7 G cap methyltransferase, RNMT, as a key mediator of T cell activation, which specifically regulates ribosome production. During T cell activation, induction of mRNA expression and ribosome biogenesis drives metabolic reprogramming, rapid proliferation and differentiation generating effector populations. We report that RNMT is induced by T cell receptor (TCR) stimulation and co-ordinates the mRNA, snoRNA and rRNA production required for ribosome biogenesis. Using transcriptomic and proteomic analyses, we demonstrate that RNMT selectively regulates the expression of terminal polypyrimidine tract (TOP) mRNAs, targets of the m7 G-cap binding protein LARP1. The expression of LARP1 targets and snoRNAs involved in ribosome biogenesis is selectively compromised in Rnmt cKO CD4 T cells resulting in decreased ribosome synthesis, reduced translation rates and proliferation failure. By enhancing ribosome abundance, upregulation of RNMT co-ordinates mRNA capping and processing with increased translational capacity during T cell activation.