Abstract
Kinetoplastid mitochondrial RNA editing, the insertion and deletion of U residues, is catalyzed by sequential cleavage, U addition or removal, and ligation reactions and is directed by complementary guide RNAs. We have purified a ~20S enzymatic complex from Trypanosoma brucei mitochondria that catalyzes a complete editing reaction in vitro. This complex possesses all four activities predicted to catalyze RNA editing: gRNA-directed endonuclease, terminal uridylyl transferase, 3' U-specific exonuclease, and RNA ligase. However, it does not contain other putative editing complex components: gRNA-independent endonuclease, RNA helicase, endogenous gRNAs or pre-mRNAs, or a 25 kDa gRNA-binding protein. The complex is composed of eight major polypeptides, three of which represent RNA ligase. These findings identify polypeptides representing catalytic editing factors, reveal the nature of this ~20S editing complex, and suggest a new model of editosome assembly.
Original language | English (US) |
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Pages (from-to) | 4069-4081 |
Number of pages | 13 |
Journal | EMBO Journal |
Volume | 16 |
Issue number | 13 |
DOIs | |
State | Published - Jul 1 1997 |
Keywords
- Editing complex
- RNA editing
- RNA lipase
- Trypanosoma brucei
- Trypanosome
ASJC Scopus subject areas
- General Neuroscience
- Molecular Biology
- General Biochemistry, Genetics and Molecular Biology
- General Immunology and Microbiology