title: The RNA chaperone activity of the Trypanosoma brucei editosome raises the dynamic of bound pre-mRNAs.
abstract: Mitochondrial transcript maturation in African trypanosomes requires an RNA editing reaction that is characterized by the insertion and deletion of U-nucleotides into otherwise non-functional mRNAs. The reaction is catalyzed by editosomes and requires guide (g)RNAs as templates. Recent data demonstrate that the binding of pre-edited mRNAs to editosomes is followed by a chaperone-type RNA remodeling reaction. Here we map the changes in RNA folding using selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE). We demonstrate that pre-mRNAs in their free state adopt intricately folded, highly stable 2D-structures. Editosome binding renders the pre-mRNAs to adopt 2D-conformations of reduced stabilities. On average about 30% of the nucleotides in every pre-mRNA are affected with a prevalence for U-nucleotides. The data demonstrate that the chaperone activity acts by increasing the flexibility of U-residues to lower their base-pairing probability. This results in a simplified RNA folding landscape with a reduced energy barrier to facilitate the binding of gRNAs. The data provide a first rational for the enigmatic U-specificity of the editing reaction.
authors.affiliation: Molecular Genetics, Darmstadt University of Technology, Schnittspahnstraße 10, 64287 Darmstadt, Germany.
authors.forename: W-Matthias
authors.initials: WM
authors.lastname: Leeder
authors.affiliation: Molecular Genetics, Darmstadt University of Technology, Schnittspahnstraße 10, 64287 Darmstadt, Germany.
authors.forename: Christin
authors.initials: C
authors.lastname: Voigt
authors.affiliation: Molecular Genetics, Darmstadt University of Technology, Schnittspahnstraße 10, 64287 Darmstadt, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Brecht
authors.affiliation: Molecular Genetics, Darmstadt University of Technology, Schnittspahnstraße 10, 64287 Darmstadt, Germany.
authors.forename: H Ulrich
authors.initials: HU
authors.lastname: Göringer
mesh_terms: D054856:G-Quadruplexes; D050259:Genes, Mitochondrial; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D015800:Protozoan Proteins / Q000378:metabolism*; D017393:RNA Editing; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D017394:RNA, Guide, Kinetoplastida / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016053:RNA, Protozoan; D016601:RNA-Binding Proteins / Q000378:metabolism*; D013816:Thermodynamics; D014346:Trypanosoma brucei brucei / Q000235:genetics* / Q000378:metabolism*
chemical_list: D015800:Protozoan Proteins; D012322:RNA Precursors; D012333:RNA, Messenger; D016053:RNA, Protozoan; D016601:RNA-Binding Proteins; D017394:RNA, Guide, Kinetoplastida