COLUMBUS, Ohio – A tiny but unexpected change to a segment of RNA in a single-cell organism looks a lot like a mistake, but is instead a change to the genetic information that is essential to the organism’s survival.
Scientists have discovered this RNA “edit” in Trypanosoma brucei, a parasite that causes sleeping sickness in Africa and Chagas disease in Latin America. Though the organism is a model system for this work, the finding could lead to a new drug target to fight the parasite if higher species don’t share this genetic behavior.
Some of the organism’s genetic activity was already known. In the case of gene products called tRNAs, which help assemble the amino acids that make proteins, T. brucei was known to have only one tRNA with a specific segment of RNA that ensures the tRNA’s proper function. Additionally, examples of RNA editing have been discovered before.
But in this case, the way genetic information necessary for the protein production process was changed – through a swap of three nucleotides for three others that are completely out of place – has never been seen before.
“These are changes for which no chemistry is known and has never been described. We don’t know what enzyme is involved and that is the million-dollar question: What mechanism is doing this? We haven’t a clue,” said Juan Alfonzo, professor of microbiology at The Ohio State University and senior author of the study.