Native mRNA editing complexes from Trypanosoma brucei mitochondria
Pollard, V.W.; Harris, M.E.; Hajduk, S.L.
EMBO Journal 11(12): 4429-4438
1992
ISSN/ISBN: 0261-4189 PMID: 1330537 Document Number: 398302
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, terminae 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, pre-edited 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.