U-Insertion/Deletion mRNA-Editing Holoenzyme: Definition in Sight

Trends Parasitol. 2016 Feb;32(2):144-156. doi: 10.1016/j.pt.2015.10.004. Epub 2015 Nov 10.


RNA editing is a process that alters DNA-encoded sequences and is distinct from splicing, 5' capping, and 3' additions. In 30 years since editing was discovered in mitochondria of trypanosomes, several functionally and evolutionarily unrelated mechanisms have been described in eukaryotes, archaea, and viruses. Editing events are predominantly post-transcriptional and include nucleoside insertions and deletions, and base substitutions and modifications. Here, we review the mechanism of uridine insertion/deletion mRNA editing in kinetoplastid protists typified by Trypanosoma brucei. This type of editing corrects frameshifts, introduces translation punctuation signals, and often adds hundreds of uridines to create protein-coding sequences. We focus on protein complexes responsible for editing reactions and their interactions with other elements of the mitochondrial gene expression pathway.

Keywords: RNA editing; Trypanosoma; guide RNA; mitochondria; polyadenylation; translation.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Gene Expression Regulation*
  • Holoenzymes / metabolism*
  • Mitochondria / genetics
  • Protozoan Proteins / genetics
  • RNA Editing*
  • RNA, Protozoan / genetics
  • RNA, Protozoan / metabolism
  • Trypanosoma brucei brucei / enzymology*
  • Trypanosoma brucei brucei / genetics*
  • Uridine / genetics
  • Uridine / metabolism


  • Holoenzymes
  • Protozoan Proteins
  • RNA, Protozoan
  • Uridine