Native mRNA editing complexes from Trypanosoma brucei mitochondria

EMBO J. 1992 Dec;11(12):4429-38.


The aim of this study was to identify multicomponent complexes involved in kinetoplastid mitochondrial mRNA editing. Mitochondrial extracts from Trypanosoma brucei were fractionated on 10-30% glycerol gradients and assayed for RNAs and activities potentially involved in editing, including pre-edited mRNA, guide RNA (gRNA), endonuclease, terminal uridylyltransferase (TUTase), RNA ligase and gRNA-mRNA chimera-forming activities. These experiments suggest that two distinct editing complexes exist. Complex I (19S) consists of gRNA, TUTase, RNA ligase and chimera-forming activity. Complex II (35-40S) is composed of gRNA, preedited mRNA, RNA ligase and chimera-forming activity. These studies provide the first evidence that editing occurs in a multicomponent complex. The possible roles of complex I, complex II and RNA ligase in editing are discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Blotting, Northern
  • DNA, Single-Stranded
  • Endonucleases / metabolism
  • Mitochondria / metabolism*
  • Molecular Sequence Data
  • Osmolar Concentration
  • RNA Editing*
  • RNA Ligase (ATP) / metabolism
  • RNA Nucleotidyltransferases / metabolism
  • RNA, Guide / metabolism
  • RNA, Messenger / metabolism*
  • RNA, Protozoan / metabolism*
  • Trypanosoma brucei brucei / metabolism*


  • DNA, Single-Stranded
  • RNA, Guide
  • RNA, Messenger
  • RNA, Protozoan
  • RNA Nucleotidyltransferases
  • UTP-RNA uridylyltransferase
  • Endonucleases
  • RNA Ligase (ATP)