title: Architecture of the trypanosome RNA editing accessory complex, MRB1.
abstract: Trypanosoma brucei undergoes an essential process of mitochondrial uridine insertion and deletion RNA editing catalyzed by a 20S editosome. The multiprotein mitochondrial RNA-binding complex 1 (MRB1) is emerging as an equally essential component of the trypanosome RNA editing machinery, with additional functions in gRNA and mRNA stabilization. The distinct and overlapping protein compositions of reported MRB1 complexes and diverse MRB1 functions suggest that the complex is composed of subcomplexes with RNA-dependent and independent interactions. To determine the architecture of the MRB1 complex, we performed a comprehensive yeast two-hybrid analysis of 31 reported MRB1 proteins. We also used in vivo analyses of tagged MRB1 components to confirm direct and RNA-mediated interactions. Here, we show that MRB1 contains a core complex comprised of six proteins and maintained by numerous direct interactions. The MRB1 core associates with multiple subcomplexes and proteins through RNA-enhanced or RNA-dependent interactions. These findings provide a framework for interpretation of previous functional studies and suggest that MRB1 is a dynamic complex that coordinates various aspects of mitochondrial gene regulation.
authors.affiliation: Department of Microbiology and Immunology, School of Medicine, State University of New York at Buffalo, Buffalo, NY 14214, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Ammerman
authors.forename: Kurtis M
authors.initials: KM
authors.lastname: Downey
authors.forename: Hassan
authors.initials: H
authors.lastname: Hashimi
authors.forename: John C
authors.initials: JC
authors.lastname: Fisk
authors.forename: Danielle L
authors.initials: DL
authors.lastname: Tomasello
authors.forename: Drahomíra
authors.initials: D
authors.lastname: Faktorová
authors.forename: Lucie
authors.initials: L
authors.lastname: Kafková
authors.forename: Tony
authors.initials: T
authors.lastname: King
authors.forename: Julius
authors.initials: J
authors.lastname: Lukes
authors.forename: Laurie K
authors.initials: LK
authors.lastname: Read
mesh_terms: D024101:Mitochondrial Proteins / Q000378:metabolism*; D021122:Protein Subunits / Q000378:metabolism; D015800:Protozoan Proteins / Q000378:metabolism*; D017393:RNA Editing; D016053:RNA, Protozoan / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D024101:Mitochondrial Proteins; D021122:Protein Subunits; D015800:Protozoan Proteins; D016053:RNA, Protozoan; D016601:RNA-Binding Proteins