RNA editing of the mitochondrial atp9 transcript from wheat.

The nucleotide sequence of the cDNA is presented, which was derived from the edited mRNA of the wheat gene for subunit 9 of the mitochondrial ATPase (atp9). Comparing the cDNA sequence with the corresponding sequence from mitochondrial DNA (1, 2), eight cytidine to uridine modifications were identified. 5 nucleotide alterations lead to amnino acid substitutions in the predicted atp9 sequence. The two N-terminal amino acid changes are consistant with partial atp9 amino acid sequence, which was recently determined by direct protein sequencing (3). So far, RNA editing of the atp9 gene has only been described for Oenothera mitochondria (4). Comparison of the wheat and Oenothera atp9 sequence reveals an amino acid identity of 97.3 %. In both sequences, RNA editing creates new TGA termination codons at identical positions.