Differential import of nuclear-encoded tRNAGly isoacceptors into solanum Tuberosum mitochondria.

In potato ( Solanum tuberosum ) mitochondria, about two-thirds of the tRNAs are encoded by the mitochondrial genome and one-third is imported from the cytosol. In the case of tRNAGly isoacceptors, a mitochondrial-encoded tRNAGly(GCC) was found in potato mitochondria, but this is likely to be insufficient to decode the four GGN glycine codons. In this work, we identified a cytosolic tRNAGly(UCC), which was found to be present in S.tuberosum mitochondria. The cytosolic tRNAGly(CCC) was also present in mitochondria, but to a lesser extent. By contrast, the cytosolic tRNAGly(GCC) could not be detected in mitochondria. This selective import of tRNAGly isoacceptors into S. tuberosum mitochondria raises further questions about the mechanism under-lying the specificity of the import process.