The RNA editing core complex (RECC) catalyzes mitochondrial U-insertion/deletion mRNA editing in trypanosomatid flagellates. Some naphthalene-based sulfonated compounds, such as C35 and MrB, competitively inhibit the auto-adenylylation activity of an essential RECC enzyme, kinetoplastid RNA editing ligase 1 (KREL1), required for the final step in editing. Previous studies revealed the ability of these compounds to interfere with the interaction between the editosome and its RNA substrates, consequently affecting all catalytic activities that comprise RNA editing. This observation implicates a critical function for the affected RNA binding proteins in RNA editing. In this study, using the inhibitory compounds, we analyzed the composition and editing activities of functional editosomes and identified the mitochondrial RNA binding proteins 1 and 2 (MRP1/2) as their preferred targets. While the MRP1/2 heterotetramer complex is known to bind guide RNA and promote annealing to its cognate pre-edited mRNA, its role in RNA editing remained enigmatic. We show that the compounds affect the association between the RECC and MRP1/2 heterotetramer. Furthermore, RECC purified post-treatment with these compounds exhibit compromised in vitro RNA editing activity that, remarkably, recovers upon the addition of recombinant MRP1/2 proteins. This work provides experimental evidence that the MRP1/2 heterotetramer is required for in vitro RNA editing activity and substantiates the hypothesized role of these proteins in presenting the RNA duplex to the catalytic complex in the initial steps of RNA editing.

• Klíčová slova
• MRP1/2, RNA editing, RNA editing initiation, RNA-binding protein, inhibitor, trypanosome,
• MeSH
• editace RNA účinky léků   genetika   MeSH
• guide RNA, Kinetoplastida účinky léků   MeSH
• ligasy antagonisté a inhibitory   MeSH
• messenger RNA genetika   MeSH
• mitochondriální proteiny genetika   MeSH
• mitochondrie účinky léků   genetika   MeSH
• proteiny vázající RNA genetika   MeSH
• protozoální proteiny genetika   MeSH
• rekombinantní proteiny genetika   MeSH
• RNA mitochondriální genetika   MeSH
• RNA protozoální genetika   MeSH
• Trypanosoma brucei brucei účinky léků   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• gBP21 protein, Trypanosoma brucei MeSH Prohlížeč
• gBP25 protein, Trypanosoma brucei MeSH Prohlížeč
• guide RNA, Kinetoplastida MeSH
• ligasy MeSH
• messenger RNA MeSH
• mitochondriální proteiny MeSH
• proteiny vázající RNA MeSH
• protozoální proteiny MeSH
• rekombinantní proteiny MeSH
• RNA mitochondriální MeSH
• RNA protozoální MeSH