The mitochondrial ND8 gene from Crithidia oncopelti is not pan-edited

RNA editing in trypanosomatid mitochondria is a process involving the insertion and deletion of uridine residues within the coding region of maxicircle messenger RNA transcripts. Twelve of the 17 known genes need editing to produce functional molecules. We have analyzed the predicted editing sites for the Crithidia oncopelti mitochondrial NADH-ubiquinone oxidoreductase subunit 8 (ND8) gene based on known mRNAs from other trypanosomatid species. All studied ND8 mRNAs undergo editing throughout the coding (and 3' noncoding) sequences (pan-editing). The 5' part of the C. oncopelti ND8 gene undergoes editing (like in Leishmania tarentolae and Trypanosoma brucei) while the 3' part of the pre-edited gene corresponds to the 3' part of edited ND8 mRNAs from other organisms. The organization of the ND8 gene in C. oncopelti mitochondrial DNA differs from all organisms investigated so far -- this gene is not pan-edited. We have also localized the guide RNA for cytochrome b between 9S rRNA and the ND8 gene. This RNA shows high homology to the gCYb-II gene of L. tarentolae and the gCyb gene of Crithidia fasciculata. A hypothetical editing pattern for the cytochrome b gene in C. oncopelti maxicircles is proposed.