title: Dual targeting is the rule for organellar aminoacyl-tRNA synthetases in Arabidopsis thaliana.
abstract: In plants, protein synthesis occurs in the cytosol, mitochondria, and plastids. Each compartment requires a full set of tRNAs and aminoacyl-tRNA synthetases. We have undertaken a systematic analysis of the targeting of organellar aminoacyl-tRNA synthetases in the model plant Arabidopsis thaliana. Dual targeting appeared to be a general rule. Among the 24 identified organellar aminoacyl-tRNA synthetases (aaRSs), 15 (and probably 17) are shared between mitochondria and plastids, and 5 are shared between cytosol and mitochondria (one of these aaRSs being present also in chloroplasts). Only two were shown to be uniquely chloroplastic and none to be uniquely mitochondrial. Moreover, there are no examples where the three aaRS genes originating from the three ancestral genomes still coexist. These results indicate that extensive exchange of aaRSs has occurred during evolution and that many are now shared between two or even three compartments. The findings have important implications for studies of the translation machinery in plants and on protein targeting and gene transfer in general.
authors.affiliation: Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS) et Université Louis Pasteur, 12 Rue du Général Zimmer, F-67084 Strasbourg Cedex, France. anne-marie.duchene@ibmp-ulp.u-strasbg.fr
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Duchêne
authors.forename: Anatoli
authors.initials: A
authors.lastname: Giritch
authors.forename: Beate
authors.initials: B
authors.lastname: Hoffmann
authors.forename: Valérie
authors.initials: V
authors.lastname: Cognat
authors.forename: Dominique
authors.initials: D
authors.lastname: Lancelin
authors.forename: Nemo M
authors.initials: NM
authors.lastname: Peeters
authors.forename: Marlyse
authors.initials: M
authors.lastname: Zaepfel
authors.forename: Laurence
authors.initials: L
authors.lastname: Maréchal-Drouard
authors.forename: Ian D
authors.initials: ID
authors.lastname: Small
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000032:analysis* / Q000235:genetics; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D002736:Chloroplasts / Q000201:enzymology; D018745:Genome, Plant; D008928:Mitochondria / Q000201:enzymology; D010802:Phylogeny
chemical_list: D000604:Amino Acyl-tRNA Synthetases