title: The RECG1 DNA Translocase Is a Key Factor in Recombination Surveillance, Repair, and Segregation of the Mitochondrial DNA in Arabidopsis.
abstract: The mitochondria of flowering plants have considerably larger and more complex genomes than the mitochondria of animals or fungi, mostly due to recombination activities that modulate their genomic structures. These activities most probably participate in the repair of mitochondrial DNA (mtDNA) lesions by recombination-dependent processes. Rare ectopic recombination across short repeats generates new genomic configurations that contribute to mtDNA heteroplasmy, which drives rapid evolution of the sequence organization of plant mtDNAs. We found that Arabidopsis thaliana RECG1, an ortholog of the bacterial RecG translocase, is an organellar protein with multiple roles in mtDNA maintenance. RECG1 targets to mitochondria and plastids and can complement a bacterial recG mutant that shows defects in repair and replication control. Characterization of Arabidopsis recG1 mutants showed that RECG1 is required for recombination-dependent repair and for suppression of ectopic recombination in mitochondria, most likely because of its role in recovery of stalled replication forks. The analysis of alternative mitotypes present in a recG1 line and of their segregation following backcross allowed us to build a model to explain how a new stable mtDNA configuration, compatible with normal plant development, can be generated by stoichiometric shift.
authors.affiliation: Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, 67084 Strasbourg, France.
authors.forename: Clémentine
authors.identifier: http://orcid.org/0000-0002-2388-4510
authors.initials: C
authors.lastname: Wallet
authors.affiliation: Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, 67084 Strasbourg, France.
authors.forename: Monique
authors.initials: M
authors.lastname: Le Ret
authors.affiliation: Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, 67084 Strasbourg, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Bergdoll
authors.affiliation: CNRS UMR7242, IREBS, Université de Strasbourg, 67412 Illkirch, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Bichara
authors.affiliation: Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, 67084 Strasbourg, France.
authors.forename: André
authors.initials: A
authors.lastname: Dietrich
authors.affiliation: Institut de Biologie Moléculaire des Plantes, CNRS UPR2357, Université de Strasbourg, 67084 Strasbourg, France jose.gualberto@ibmp-cnrs.unistra.fr.
authors.forename: José M
authors.identifier: http://orcid.org/0000-0002-7296-2618
authors.initials: JM
authors.lastname: Gualberto
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair; D004261:DNA Replication; D004272:DNA, Mitochondrial / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D055786:Gene Knockout Techniques; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D008958:Models, Molecular; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D018087:Plastids / Q000378:metabolism; D011995:Recombination, Genetic
chemical_list: D029681:Arabidopsis Proteins; D004272:DNA, Mitochondrial; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D026901:Membrane Transport Proteins; C000622190:RECG1 protein, Arabidopsis