Seattle Biomedical Research Institute, Seattle, Washington 98109-1651.
Mitochondrial MURF3 transcripts of T. brucei are extensively edited by the addition and deletion of uridines. The editing creates potential initiation and termination codons and a continuous open reading frame. The predicted amino acid sequence has homology to a subunit of NADH dehydrogenase (ND7). ND7 is independently edited in two distinct domains, suggesting two editing initiation sites. Editing in the two domains is differentially regulated: the 5' domain is edited in both bloodstream and procyclic forms but the 3' domain is completely edited only in the bloodstream form. Two potential guide RNA (gRNA) coding sequences were identified in the same minicircle. One is complementary to edited sequence in the 5' domain, the other to edited sequence in the 3' domain.