Poster number 97 submitted by Boyoon Yang
Gathering insights into the importance of ADR-1/ADR-2 interaction in RNA editing in vivo
Boyoon Yang (Molecular and Cellular Biochemistry, Indiana University Bloomington), Pranathi Vadlamani (Biology departement, Indiana University Bloomington), Heather Hundley (Biology departement, Indiana University Bloomington)
All animals generate transcriptomic diversity by modifying genetic information through RNA editing. A-to-I RNA editing is mediated by Adenosine deaminases that act on RNA (ADARs). ADARs convert specific adenosines into inosines in double-stranded RNA (dsRNA). ADARs have a high potential as therapeutic means to correct specific G-to-A mutations at the RNA level without modifying the genome. Therefore, it is crucial to understand how ADARs bind specific mRNAs and select an individual adenosine for editing in vivo.
For ADARs to target specific adenosines, ADARs have to dimerize, bind RNA, and catalyze deamination. While residues crucial for RNA binding and editing are extensively studied, residues important for protein-protein interaction of ADARs are poorly understood. In Caenorhabditis elegans, RNA editing is mediated by ADR-2, whereas ADR-1 is an editing-deficient ADAR family member. Our lab showed that the majority (80%) of ADR-2 bound transcripts require the help of ADR-1, and ADR-1 and ADR-2 heterodimerize independent of dsRNA binding. To investigate which domain of ADARs plays a role in both RNA editing and protein-protein interaction in vivo, we have generated ADAR mutants lacking the deaminase domain by CRISPR. In vivo assays of these novel mutants demonstrated that the dsRBD of ADR-2 is sufficient for ADR-1/ADR-2 interaction. Furthermore, the lack of the ADR-1 deaminase domain, while not affecting the heterodimerization, results in defects in RNA editing in vivo, suggesting that an inactive deaminase domain might play a role in editing efficiency. Elucidating the mechanism of how ADR-1 and ADR-2 dimerize to edit target mRNAs will provide new insights into how A-to-I editing is mediated in vivo.
Keywords: RNA editing, ADAR, protein-protein interaction