Editing of Trypanosoma brucei maxicircle CR5 mRNA generates variable carboxy terminal predicted protein sequences

RNA editing post-transcriptlonally modifies several mRNAs from the maxicircle of kinetoplastld parasites by addition and removal of urldlne residues. We report here that maxicircle CR5 transcripts of Trypanosoma bruce are edited in two domains separated by an eight nucleotlde sequence that remains unedited. The large 5′ domain is edited to a consensus sequence while the smaller 3′ domain is edited to multiple final sequences. In all, 205-217 Us are inserted and 13-16 encoded urldlnes are deleted from the CR5 mRNA, producing a mature transcript 75 - 80% larger than the unedited transcript. The edited RNAs predict small, highly hydrophoblc proteins. The carboxy terminal 15-30% of these predicted proteins have multiple different amlno acid sequences as a result of the variable edited 3′ mRNA sequence, but these fall into two families of sequence. Limited amlno acid sequence and hydrophobicity profile similarities suggest that the protein encoded by edited CR5 mRNA may be a subunlt of NADH dehydrogenase.