Identification of a nuclear protein in Trypanosoma brucei with homology to RNA-binding proteins from cis-splicing systems

• Published in: Molecular and biochemical parasitology 1998-11, Vol.97 (1), p.1-11
• Main Authors: Manger, Ian D, Boothroyd, John C
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Blotting, Western; Cloning, Molecular; Fluorescent Antibody Technique, Indirect; Genes, Protozoan; Molecular Sequence Data; Nuclear Proteins - analysis; Nuclear Proteins - genetics; Open Reading Frames - genetics; Polymerase Chain Reaction - methods; Protozoan Proteins - analysis; Protozoan Proteins - genetics; RNA recognition motif; RNA, Protozoan - analysis; RNA-binding protein; RNA-Binding Proteins - analysis; RNA-Binding Proteins - genetics; Sequence Alignment; Trans-splicing; Trans-Splicing - genetics; Trypanosoma brucei; Trypanosoma brucei brucei - chemistry; Trypanosoma brucei brucei - genetics
• ISSN: 0166-6851; 1872-9428
• DOI: 10.1016/S0166-6851(98)00118-2

Gene expression in trypanosomes is controlled at the level of pre-mRNA maturation via trans-splicing and polyadenylation and through changes in mRNA stability. To identify the trans- acting factors involved in this regulation, we have used a degenerate PCR approach to clone genes encoding the RNA recognition motif (RRM) consensus. We have identified a single-copy gene encoding a protein (designated RRM1) which contains three consensus RRM motifs, two tandem copies of a retroviral gag- like CCHC ‘zinc finger’ and an arginine-serine (RS) rich region. Western blotting indicates that RRM1 is expressed in both procyclic and bloodstream-form trypanosomes and has an apparent mobility on SDS-PAGE of ca. 70 Kd. RRM1 is localized in the trypanosome nucleus in substructures which may be functionally analogous to the ‘speckles’ associated with cis-splicing in higher eukaryotic cells. The structure of RRM1, its pattern of expression and its intracellular location suggest that it may play a role in trans-splicing.