Dual targeting of organellar seryl-tRNA synthetase to maize mitochondria and chloroplasts

• Published in: Plant cell reports 2008-07, Vol.27 (7), p.1157-1168
• Main Authors: Rokov-Plavec, Jasmina, Dulic, Morana, Duchêne, Anne-Marie, Weygand-Durasevic, Ivana
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Cell Biology; Cell Biology and Morphogenesis; Cellular Biology; Chloroplasts - metabolism; Corn; Fundamental and applied biological sciences. Psychology; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Immunoblotting; Life Sciences; Mitochondria - metabolism; Molecular Sequence Data; Plant Biochemistry; Plant physiology and development; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Sciences; Protein Transport; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Serine-tRNA Ligase - genetics; Serine-tRNA Ligase - metabolism; Zea mays - enzymology; Zea mays - genetics; Zea mays - metabolism
• ISSN: 0721-7714; 1432-203X
• DOI: 10.1007/s00299-008-0542-9

Aminoacyl-tRNA synthetases (AARSs) play a critical role in translation and are thus required in three plant protein-synthesizing compartments: cytosol, mitochondria and plastids. A systematic study had previously shown extensive sharing of organellar AARSs from Arabidopsis thaliana, mostly between mitochondria and chloroplasts. However, distribution of AARSs from monocot species, such as maize, has never been experimentally investigated. Here we demonstrate dual targeting of maize seryl-tRNA synthetase, SerZMo, into both mitochondria and chloroplasts using combination of complementary methods, including in vitro import assay, transient expression analysis of green fluorescent protein (GFP) fusions and immunodetection. We also show that SerZMo dual localization is established by the virtue of an ambiguous targeting peptide. Full-length SerZMo protein fused to GFP is targeted to chloroplast stromules, indicating that SerZMo protein performs its function in plastid stroma. The deletion mutant lacking N-terminal region of the ambiguous SerZMo targeting peptide was neither targeted into mitochondria nor chloroplasts, indicating the importance of this region in both mitochondrial and chloroplastic import.