A single gene of chloroplast origin codes for mitochondrial and chloroplastic methionyl-tRNA synthetase in Arabidopsis thaliana

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 95; no. 18; pp. 11014 - 11019
• Main Authors: Menand, B. (Universite Louis Pasteur, Strasbourg, France.), Marechal-Drouard, L, Sakamoto, W, Dietrich, A, Wintz, H
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 01.09.1998; National Acad Sciences; The National Academy of Sciences
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ADN; Amino Acid Sequence; AMINO ACID SEQUENCES; Amino acids; ANIMAL PROTEINS; Arabidopsis - enzymology; Arabidopsis - genetics; ARABIDOPSIS THALIANA; Base Sequence; BIOCHEMISTRY; BIOCHIMIE; Biological Sciences; Biological Transport; BIOQUIMICA; CHEMICAL COMPOSITION; CHLOROPLAST DNA; CHLOROPLASTE; CHLOROPLASTS; Chloroplasts - enzymology; CLOROPLASTO; COMPLEMENTARY DNA; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; CYTOCHEMISTRY; DNA; DNA, Complementary; Enzymes; ENZYMIC ACTIVITY; FLUORESCENCE; FLUORESCENCIA; GENBANK/F19928; GENBANK/T41822; GENBANK/Y13943; GENE; GENES; GREEN FLUORESCENT PROTEIN; Green Fluorescent Proteins; LIGASAS; LIGASE; LIGASES; Luminescent Proteins - genetics; METABOLISME DES PROTEINES; METABOLISMO PROTEICO; Methionine-tRNA Ligase - genetics; Methionine-tRNA Ligase - isolation & purification; Methionine-tRNA Ligase - metabolism; MITOCHONDRIA; Mitochondria - enzymology; MITOCHONDRIE; MITOCONDRIA; MOLECULAR SEQUENCE DATA; NUCLEOTIDE SEQUENCE; Organelles; Peas; Plant cells; PROTEIN METABOLISM; PROTEIN TRANSPORT; PROTEINAS; PROTEINAS RECOMBINANTES; PROTEINE; PROTEINE RECOMBINANTE; PROTEINS; RECOMBINANT PROTEINS; SECUENCIA NUCLEOTIDICA; SEQUENCE NUCLEOTIDIQUE; SIGNAL PEPTIDE; STRUCTURAL GENES; Transfer RNA
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.95.18.11014

One-fifth of the tRNAs used in plant mitochondrial translation is coded for by chloroplast-derived tRNA genes. To understand how aminoacyl-tRNA synthetases have adapted to the presence of these tRNAs in mitochondria, we have cloned an Arabidopsis thaliana cDNA coding for a methionyl-tRNA synthetase. This enzyme was chosen because chloroplast-like elongator tRNA(Met) genes have been described in several plant species, including A. thaliana. We demonstrate here that the isolated cDNA codes for both the chloroplastic and the mitochondrial methionyl-tRNA synthetase (MetRS). The protein is transported into isolated chloroplasts and mitochondria and is processed to its mature form in both organelles. Transient expression assays using the green fluorescent protein demonstrated that the N-terminal region of the MetRS is sufficient to address the protein to both chloroplasts and mitochondria. Moreover, characterization of MetRS activities from mitochondria and chloroplasts of pea showed that only one MetRS activity exists in each organelle and that both are indistinguishable by their behavior on ion exchange and hydrophobic chromatographies. The high degree of sequence similarity between A. thaliana and Synechocystis MetRS strongly suggests that the A. thaliana MetRS gene described here is of chloroplast origin