Trypanosoma brucei mitochondrial CR4 gene encodes an extensively edited mRNA with completely edited sequence only in bloodstream forms.

Several kinetoplastid mitochondrial genes cannot be expressed without RNA editing of their transcripts to create a functional open reading frame. We have examined one such mitochondrial gene, CR4, in Trypanosoma brucei EATRO164 and find extensive editing of transcripts in both bloodstream and procyclic life cycle stages. However, a consensus edited sequence for the entire mRNA occurs only in the bloodstream stage. The unedited CR4 transcript is 283 nucleotides in length, not including the poly(A) tail. A total of 325 uridines are inserted, and 40 uridines deleted, to create the mature mRNA which encodes a very hydrophobic protein.