Reduced requirement for RNA editing in the mitochondrial cox3 transcript of Olea europaea L

Transcripts from the mitochondrial cox3 locus in Olea europaea L. are edited in ten nucleotide positions. Nine of these C-to-U transitions affect 3.4% of the genomically encoded amino-acid identity to specify a COXIII polypeptide better conserved in evolution. RNA editing of cox3 in olive tree mitochondria is, thus, less extensive than in the other higher plants so far investigated. This low RNA editing frequency might correlate with both the GC content observed in the cox3 gene and the phylogenetic position of Olea.