Expression ofArabidopsis thalianaMitochondrial Alanyl-tRNA Synthetase Is Not Sufficient to Trigger Mitochondrial Import of tRNAAlain Yeast

Hakim Mireau, Anne Cosset, Laurence Maréchal-Drouard, Thomas D. Fox, Ian D. Small, André Dietrich
2000 Journal of Biological Chemistry  
It has often been suggested that precursors to mitochondrial aminoacyl-tRNA synthetases are likely carriers for mitochondrial import of tRNAs in those organisms where this process occurs. In plants, it has been shown that mutation of U 70 to C 70 in Arabidopsis thaliana tRNA Ala (UGC) blocks aminoacylation and also prevents import of the tRNA into mitochondria. This suggests that interaction of tRNA Ala with alanyl-tRNA synthetase (AlaRS) is necessary for import to occur. To test whether this
more » ... test whether this interaction is sufficient to drive import, we co-expressed A. thaliana tRNA Ala (UGC) and the precursor to the A. thaliana mitochondrial AlaRS in Saccharomyces cerevisiae. The A. thaliana enzyme and its cognate tRNA were correctly expressed in yeast in vivo. However, although the plant AlaRS was efficiently imported into mitochondria in the transformed strains, we found no evidence for import of the A. thaliana tRNA Ala nor of the endogenous cytosolic tRNA Ala isoacceptors. We conclude that at least one other factor besides the mitochondrial AlaRS precursor must be involved in mitochondrial import of tRNA Ala in plants.
doi:10.1074/jbc.275.18.13291 pmid:10788435 fatcat:n5cewn6nsngwte6g2c7fhy33te