Coordination of Adenosine to Inosine Editing and mRNA Splicing

• Applicant: Dr. Konstantin Licht
• Subject Area: Biochemistry ; Evolutionary Cell and Developmental Biology (Zoology)
• Term: from 2014 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 257125858

Several mechanisms increase the diversity of gene products in multicellular organisms. In particular, two processes, alternative mRNA splicing and adenosine to inosine editing raise diversity on transcript level. Adenosine to Inosine Editing is catalyzed by two enzymes: ADAR1 and ADAR2 (ADAR = adenosine deaminase acting on RNA). Editing can change mRNA sequence information as well as mRNA secondary structure (inosines form different basepairs than adenosines) and thereby can influence splicing. Vice versa splicing impacts editing since exonic editing sites frequently depend on intronic sites that guide editing. Therefore, I plan a systematic analysis of the interplay between both processes. My aims are to: 1) Analyze the influence of editing on alternative splicing by transcriptome analysis of RNA from editing deficient and wild-type animals using RNA-seq2) Determine the impact of splicing on editing by treating cells with splicing inhibitorsFirst, I will use knockout mouse embryos which are editing deficient. I will use RNA-seq to compare splicing patterns in wildtype and editing deficient embryos. Moreover, I plan to determine the impact of ADAR2 on splicing in adult mice. To analyze how splicing can impact editing I will use spliceosome inhibitors and apply them to cultured cells. Subsequently I will compare treated and control cells. I expect that the number of certain edited transcripts increases when splicing is inhibited because the intronic elements that guide editing will remain in the pre-mRNA for a longer time. In sum, the proposed project contains a transcriptome-wide analysis of the impact of editing on splicing as well as a detailed mechanistic analysis using model substrates. The biological significance of the project is very high since alternative splicing as well as editing increases receptor diversity and protein diversity as a whole within the brain. Moreover, multiple transcripts are subject to alternative splicing as well as editing, arguing for the need of tight regulation between both processes. In addition a series of neuronal disorders (e.g. schizophrenia) has been connected with erroneous splicing or editing which underlines the importance of tight control.

• DFG Programme: Research Fellowships
• International Connection: Austria
• Host: Professor Dr. Michael F. Jantsch