Cyanophora paradoxa mitochondrial tRNAs play a double game.
Fiche publication
Date publication
mars 2021
Journal
The Plant journal : for cell and molecular biology
Auteurs
Membres identifiés du Cancéropôle Est :
Dr MARÉCHAL-DROUARD Laurence
Tous les auteurs :
Salinas-Giegé T, Ubrig E, Drouard L
Lien Pubmed
Résumé
Present-day mitochondria derive from a single endosymbiosis of an α-proteobacteria into a proto-eukaryotic cell. Since this monophyletic event, mitochondria have considerably evolved, and unique traits have been independently acquired in the different eukaryotic kingdoms. Mitochondrial genome expression and RNA metabolism have indeed highly diverged. Here, Cyanophora paradoxa, a freshwater alga considered a living fossil among photosynthetic organisms, represents an exciting model to study mitochondrial gene expression evolution. As expected, fully mature tRNAs are released from primary transcripts to function in mitochondrial translation. Besides, we show that these tRNAs also take part in an mRNA processing punctuation mechanism in a nonconventional manner leading to mRNA-tRNA hybrids with a CCA triplet at their 3'-extremities. In this case, tRNAs are likely used as stabilizing structures impeding mRNA degradation by exonucleases. From our data, we propose that the present-day tRNA-like elements (t-elements) found at the 3'-termini of mitochondrial mRNAs in land plants originate from true tRNAs as those observed in the mitochondria of this basal photosynthetic glaucophyte.
Mots clés
evolution, green lineage, mitochondrial RNA processing, organelles
Référence
Plant J. 2021 Mar 5;: