title: gRNA/pre-mRNA annealing and RNA chaperone activities of RBP16.
abstract: Editing in trypanosomes involves the addition or deletion of uridines at specific sites to produce translatable mitochondrial mRNAs. RBP16 is an accessory factor from Trypanosoma brucei that affects mitochondrial RNA editing in vivo and also stimulates editing in vitro. We report here experiments aimed at elucidating the biochemical activities of RBP16 involved in modulating RNA editing. In vitro RNA annealing assays demonstrate that RBP16 significantly stimulates the annealing of gRNAs to cognate pre-mRNAs. In addition, RBP16 also facilitates hybridization of partially complementary RNAs unrelated to the editing process. The RNA annealing activity of RBP16 is independent of its high-affinity binding to gRNA oligo(U) tails, consistent with the previously reported in vitro editing stimulatory properties of the protein. In vivo studies expressing recombinant RBP16 in mutant Escherichia coli strains demonstrate that RBP16 is an RNA chaperone and that in addition to RNA annealing activity, it contains RNA unwinding activity. Our data suggest that the mechanism by which RBP16 facilitates RNA editing involves its capacity to modulate RNA secondary structure and promote gRNA/pre-mRNA annealing.
authors.affiliation: Department of Microbiology and Immunology, School of Medicine, State University of New York at Buffalo, Buffalo, New York 14214, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Ammerman
authors.forename: John C
authors.initials: JC
authors.lastname: Fisk
authors.forename: Laurie K
authors.initials: LK
authors.lastname: Read
mesh_terms: D000818:Animals; D004926:Escherichia coli / Q000235:genetics; D018832:Molecular Chaperones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009690:Nucleic Acid Conformation; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017393:RNA Editing; D012322:RNA Precursors / Q000737:chemistry* / Q000378:metabolism; D017394:RNA, Guide, Kinetoplastida / Q000737:chemistry* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D018832:Molecular Chaperones; D015800:Protozoan Proteins; C118900:RBP16 protein, Trypanosoma; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D011994:Recombinant Proteins; D017394:RNA, Guide, Kinetoplastida