title: The RAD52-like protein ODB1 is required for the efficient excision of two mitochondrial introns spliced via first-step hydrolysis.
abstract: Transcript splicing in plant mitochondria involves numerous nucleus-encoded factors, most of which are of eukaryotic origin. Some of these belong to protein families initially characterised to perform unrelated functions. The RAD52-like ODB1 protein has been reported to have roles in homologous recombination-dependent DNA repair in the nuclear and mitochondrial compartments in Arabidopsis thaliana. We show that it is additionally involved in splicing and facilitates the excision of two cis-spliced group II introns, nad1 intron 2 and nad2 intron 1, in Arabidopsis mitochondria. odb1 mutants lacking detectable amounts of ODB1 protein over-accumulated incompletely spliced nad1 and nad2 transcripts. The two ODB1-dependent introns were both found to splice via first-step hydrolysis and to be released as linear or circular molecules instead of lariats. Our systematic analysis of the structures of excised introns in Arabidopsis mitochondria revealed several other hydrolytically spliced group II introns in addition to nad1 intron 2 and nad2 intron 1, indicating that ODB1 is not a general determinant of the hydrolytic splicing pathway.
authors.affiliation: Institut de Biologie Moléculaire des Plantes-CNRS-UPR2357, Université de Strasbourg, Strasbourg, France jose.gualberto@ibmp-cnrs.unistra.fr.
authors.forename: José M
authors.initials: JM
authors.lastname: Gualberto
authors.affiliation: Institut de Biologie Moléculaire des Plantes-CNRS-UPR2357, Université de Strasbourg, Strasbourg, France.
authors.forename: Monique
authors.initials: M
authors.lastname: Le Ret
authors.affiliation: Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Beator
authors.affiliation: Molekulare Zellbiologie der Pflanzen, Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany kristina.kuehn@hu-berlin.de.
authors.forename: Kristina
authors.initials: K
authors.lastname: Kühn
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006868:Hydrolysis; D007438:Introns; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D009245:NADH Dehydrogenase / Q000235:genetics / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012322:RNA Precursors / Q000378:metabolism; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism; D000077278:RNA, Mitochondrial
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D024101:Mitochondrial Proteins; C579794:ODB1 protein, Arabidopsis; D012322:RNA Precursors; D012333:RNA, Messenger; D000077278:RNA, Mitochondrial; D012313:RNA; D009245:NADH Dehydrogenase; C000594053:Nad1 protein, Arabidopsis