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A single base change prevents import of cytosolic tRNA Ala into mitochondria in transgenic plants
Author(s) -
Dietrich André,
MaréchalDrouard Laurence,
Carneiro Vera,
Cosset Anne,
Small Ian
Publication year - 1996
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1996.10050913.x
Subject(s) - transfer rna , aminoacylation , biology , mitochondrion , mutant , t arm , translation (biology) , protein biosynthesis , biochemistry , cytosol , aminoacyl trna synthetase , genetics , microbiology and biotechnology , rna , gene , messenger rna , enzyme
Plant mitochondria do not contain a full set of tRNA genes, and the additional tRNAs needed for protein synthesis (including tRNA Ala ) are imported from the cytosol. The import process appears to be highly specific for certain tRNAs, and it has been suggested that the cognate aminoacyl‐tRNA synthetases may be responsible for this specificity. In order to test this, we have grown transgenic tobacco plants expressing Arabidopsis thaliana tRNA Ala carrying a U 70 to C 70 mutation, which we have previously shown blocks aminoacylation by the plant alanyl‐tRNA synthetase. Unlike the wild‐type tRNA Ala , the mutant tRNA is not present in the mitochondrial tRNA fraction. This is the first report of a tRNA mutation which prevents mitochondrial import and strongly supports the hypothesis that aminoacyl‐tRNA synthetases are involved in this process in plants. Insertion of four bases into the anticodon loop of tRNA Ala does not prevent mitochondrial import, implying that the tRNA might not need to participate in translation to be imported.