A 3′ terminal RNA uridylyltransferase was purified from mitochondria of Leishmania tarentolae and the gene cloned and expressed from this species and from Trypanosoma brucei. The enzyme is specific for 3′ U-addition in the presence of Mg2+. TUTase is present in vivo in at least two stable configurations: one contains a ∼500 kDa TUTase oligomer and the other a ∼700 kDa TUTase complex. Anti-TUTase antiserum specifically coprecipitates a small portion of the p45 and p50 RNA ligases and approximately 40% of the guide RNAs. Inhibition of TUTase expression in procyclic T. brucei by RNAi downregulates RNA editing and appears to affect parasite viability.
Aphasizhev, R., Sbicego, S., Peris, M., Jang, S. H., Aphasizheva, I., Simpson, A. M., … Simpson, L. (2002). Trypanosome mitochondrial 3′ terminal uridylyl transferase (TUTase): The key enzyme in U-insertion/deletion RNA editing. Cell, 108(5), 637–648. https://doi.org/10.1016/S0092-8674(02)00647-5