| Zdroj: |
Meehan, J, McDermott, S M, Ivens, A, Goodall, Z, Chen, Z, Yu, Z, Woo, J, Rodshagen, T, McCleskey, L, Seachrist, R, Stuart, K D, Zeng, L, Rouskin, S, Savill, N J, Schnaufer, A, Zhang, X & Cruz-Reyes, J 2023, ' Trypanosome RNA helicase KREH2 differentially controls noncanonical editing and putative repressive structure via a novel proposed “bifunctional” gRNA in mRNA A6 ', NAR Genomics and Bioinformatics . https://doi.org/10.1093/nar/gkad453 |
| Popis: |
U-insertion/deletion (U-indel) RNA editing in trypanosome mitochondria is directed by guide RNAs (gRNAs). This editing may developmentally control respiration in bloodstream forms (BSF) and insect procyclic forms (PCF). Holo-editosomes include the accessory RNA Editing Substrate Binding Complex (RESC) and RNA Editing Helicase 2 Complex (REH2C), but the specific proteins controlling differential editing remain unknown. Also, RNA editing appears highly error prone because most U-indels do not match the canonical pattern. However, despite extensive non-canonical editing of unknown functions, accurate canonical editing is required for normal cell growth. In PCF, REH2C controls editing fidelity in RESC-bound mRNAs. Here, we report that KREH2, a REH2C-associated helicase, developmentally controls programmed non-canonical editing, including an abundant 3′ element in ATPase subunit 6 (A6) mRNA. The 3′ element sequence is directed by a proposed novel regulatory gRNA. In PCF, KREH2 RNAi-knockdown up-regulates the 3′ element, which establishes a stable structure hindering element removal by canonical initiator-gRNA-directed editing. In BSF, KREH2-knockdown does not up-regulate the 3′ element but reduces its high abundance. Thus, KREH2 differentially controls extensive non-canonical editing and associated RNA structure via a novel regulatory gRNA, potentially hijacking factors as a ‘molecular sponge’. Furthermore, this gRNA is bifunctional, serving in canonical CR4 mRNA editing whilst installing a structural element in A6 mRNA. |
