The effect of RNA interference Down-regulation of RNA editing 3'-terminal uridylyl transferase (TUTase) 1 on mitochondrial de novo protein synthesis and stability of respiratory complexes in Trypanosoma brucei.
Inhibition of RNA editing by down-regulation of expression of the mitochondrial RNA editing TUTase 1 by RNA interference had profound effects on kinetoplast biogenesis in Trypanosoma brucei procyclic cells. De novo synthesis of the apocytochrome b and cytochrome oxidase subunit I proteins was no longer detectable after 3 days of RNAi. The effect on protein synthesis correlated with a decline in the levels of the assembled mitochondrial respiratory complexes III and IV, and also cyanide-sensitive oxygen uptake. The steady-state levels of nuclear-encoded subunits of complexes III and IV were also significantly decreased. Because the levels of the corresponding mRNAs were not affected, the observed effect was likely due to an increased turnover of these imported mitochondrial proteins. This induced protein degradation was selective for components of complexes III and IV, because little effect was observed on components of the F(1).F(0)-ATPase complex and on several other mitochondrial proteins.
Nebohácová
Martina
M
Howard Hughes Medical Institute and Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California 90095, USA.
Maslov
Dmitri A
DA
Falick
Arnold M
AM
Simpson
Larry
L
D000818:Animals; D045303:Cytochromes b / Q000096:biosynthesis; D045222:Electron Transport Chain Complex Proteins / Q000378:metabolism; D014450:Electron Transport Complex III / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000096:biosynthesis; D005786:Gene Expression Regulation; D008928:Mitochondria / Q000378:metabolism*; D010101:Oxygen Consumption; D015800:Protozoan Proteins / Q000096:biosynthesis*; D012313:RNA / Q000235:genetics; D017393:RNA Editing / Q000235:genetics*; D034622:RNA Interference; D012316:RNA Nucleotidyltransferases / Q000235:genetics*; D000077278:RNA, Mitochondrial; D014346:Trypanosoma brucei brucei / Q000378:metabolism* / Q000648:ultrastructure; D014529:Uridine
D045222:Electron Transport Chain Complex Proteins; D015800:Protozoan Proteins; D000077278:RNA, Mitochondrial; D012313:RNA; D045303:Cytochromes b; D003576:Electron Transport Complex IV; D012316:RNA Nucleotidyltransferases; C031687:UTP-RNA uridylyltransferase; D014450:Electron Transport Complex III; D014529:Uridine