In kinetoplastid protists, all mitochondrial tRNAs are encoded in the nucleus and imported from the cytoplasm to maintain organellar translation. This also applies to the tryptophanyl tRNA (tRNATrp) encoded by a single-copy nuclear gene, with a CCA anticodon to read UGG codon used in the cytosolic translation. Yet, in the mitochondrion it is unable to decode the UGA codon specifying tryptophan. Following mitochondrial import of tRNATrp, this problem is solved at the RNA level by a single C34 to U34 editing event that creates the UCA anticodon, recognizing UGA. To identify the enzyme responsible for this critical editing activity, we scrutinized the genome of Trypanosoma brucei for putative cytidine deaminases as the most likely candidates. Using RNAi silencing and poisoned primer extension, we have identified a novel deaminase enzyme, named here TbmCDAT for mitochondrial Cytidine Deaminase Acting on tRNA, which is responsible for this organelle-specific activity in T. brucei. The ablation of TbmCDAT led to the downregulation of mitochondrial protein synthesis, supporting its role in decoding the UGA tryptophan codon.

• Klíčová slova
• Mitochondrion, cytidine deaminase, editing, trypanosoma, tryptophanyl tRNA,
• MeSH
• cytidin chemie   genetika   MeSH
• cytidindeaminasa genetika   metabolismus   MeSH
• konformace nukleové kyseliny MeSH
• mitochondrie enzymologie   genetika   MeSH
• RNA mitochondriální analýza   genetika   MeSH
• RNA protozoální analýza   genetika   MeSH
• RNA transferová Trp MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• sekvenční homologie MeSH
• terminační kodon * MeSH
• Trypanosoma brucei brucei genetika   růst a vývoj   metabolismus   MeSH
• uridin chemie   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cytidin MeSH
• cytidindeaminasa MeSH
• RNA mitochondriální MeSH
• RNA protozoální MeSH
• RNA transferová Trp MeSH
• terminační kodon * MeSH
• uridin MeSH