The mitochondrial methylation potential gates mitoribosome assembly

Abstract S-adenosylmethionine (SAM) is the principal methyl donor in cells and is essential for mitochondrial gene expression, influencing RNA modifications, translation, and ribosome biogenesis. Using direct long-read RNA sequencing in mouse tissues and embryonic fibroblasts, we show that processin...

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Main Authors: Ruth I. C. Glasgow, Vivek Singh, Lucía Peña-Pérez, Alissa Wilhalm, Marco F. Moedas, David Moore, Florian A. Rosenberger, Xinping Li, Ilian Atanassov, Mira Saba, Miriam Cipullo, Joanna Rorbach, Anna Wedell, Christoph Freyer, Alexey Amunts, Anna Wredenberg
Format: Article
Language:English
Published: Nature Portfolio 2025-06-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-60977-x
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Summary:Abstract S-adenosylmethionine (SAM) is the principal methyl donor in cells and is essential for mitochondrial gene expression, influencing RNA modifications, translation, and ribosome biogenesis. Using direct long-read RNA sequencing in mouse tissues and embryonic fibroblasts, we show that processing of the mitochondrial ribosomal gene cluster fails in the absence of mitochondrial SAM, leading to an accumulation of unprocessed precursors. Proteomic analysis of ribosome fractions revealed these precursors associated with processing and assembly factors, indicating stalled biogenesis. Structural analysis by cryo-electron microscopy demonstrated that SAM-dependent methylation is required for peptidyl transferase centre formation during mitoribosome assembly. Our findings identify a critical role for SAM in coordinating mitoribosomal RNA processing and large subunit maturation, linking cellular methylation potential to mitochondrial translation capacity.
ISSN:2041-1723