Sequence dependence of tRNA Gly import into tobacco mitochondria

Abstract

Plant mitochondrial genomes lack a number of tRNA genes and the corresponding tRNAs, which are nuclear-encoded, are imported from the cytosol. We show that specific import of tRNA Gly isoacceptors occurs in tobacco mitochondria: tRNA Gly(UCC) and tRNA Gly(CCC) are cytosolic and mitochondrial, while tRNA Gly(GCC) is found only in the cytosol. Exchange of sequences between tRNA Gly(UCC) and tRNA Gly(GCC) shows that the anticodon and D-domain are essential for tRNA Gly(UCC) import. However the reverse mutations in tRNA Gly(GCC) are not sufficient to promote its import into tobacco mitochondria.