Poster abstracts
Poster number 37 submitted by Brianna Tylec
Editing of Minimally Edited RNA CYb in Trypanosoma brucei
Brianna L. Tylec (Department of Microbiology & Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY), Rachel M. Simpson (Department of Microbiology & Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY), Runpu Chen (Department of Computational Science and Engineering, University at Buffalo, Buffalo NY), Yijun Sun (Department of Computational Science and Engineering, University at Buffalo, Buffalo NY), Laurie K. Read (Department of Microbiology & Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY)
Abstract:
Trypanosoma brucei, the causative agent of African sleeping sickness, is an early branching Eukaryote belonging to the Class Kinetoplastida. Members of this group undergo uridine (U) insertion/deletion editing of most mitochondrial RNAs. Trans-acting gRNAs are sequentially utilized as templates, ensuring the general 3' to 5' progression of editing along the mRNA to generate a translatable open reading frame. Editing involves multiple protein subcomplexes including the non-enzymatic RNA Editing Substrate Binding Complex (RESC), composed of the RNA Editing Mediator Complex (REMC) and Guide RNA Binding Complex (GRBC). Nine mitochondrial RNAs are edited throughout the length of the transcript, termed "pan-edited", while three genes only require editing over a small portion of the reading frame. These "minimally edited" RNAs are a good model for studying editing since they require only 1-2 gRNAs to complete the process. We characterized the editing of the minimally edited RNA, CYb, in procyclic form T. brucei using the Trypanosome RNA Editing Alignment Tool (TREAT), which takes advantage of high-throughput sequencing technology as well as a uridine in/del specific alignment algorithm to evaluate the extent of editing in a large pool of pre-, partially, and fully edited transcripts. We then knocked down expression of four proteins that play a role in RNA editing (RESC factors TbRGG2 and GAP1, and non-RESC factors RBP16 and MRP1/2), and assessed the effects of the knockdowns on editing initiation and progression of CYb mRNA. We found that editing intrinsically pauses at the steps of initiation and gRNA exchange, and that RBP16 and MRP1/2 knockdowns result in depletion of edited mRNA by different mechanisms.
Keywords: Trypanosoma brucei, RNA Editing