Determination of physiologically relevant RNA substrate(s) and design of small-molecule inhibitors for Zα domains as potential intervention strategies for viral infections and autoimmunity

Objectif

DNA/RNA molecules adopting the Z-conformation have been known to possess immunogenic properties. However, their biological role and importance has been a topic of debate for many years. The discovery of Z-DNA/RNA binding domains (Zα domains) in varied proteins that are involved in the innate immune response, such as the interferon induced form of the RNA editing enzyme ADAR1 (p150), Z-DNA binding protein 1 (ZBP1), the fish kinase PKZ and the pox-virus inhibitor of interferon response E3L, indicates important roles of Z-DNA/RNA in immunity and self/non-self-discrimination. Such Zα domain-containing proteins recognize Z-DNA/RNA in a conformation-specific manner. Recent studies have implicated these domains in viral recognition. Given these important emerging roles for the Zα domains, it is pivotal to understand the physiologically-relevant nucleic acid substrate for them. In this proposal, we propose to deduce the physiologically relevant substrates for Zα domains from ADAR1 p150 and ZBP1 employing next-generation RNA-seq methodologies. Knowledge on the biochemical and structural aspects of substrate specificity and substrate recognition by these domains would yield important insights into the specific roles these proteins play in the physiological context and would propel efforts at designing effective and specific small-molecule inhibitors against these proteins. Utilizing next-generation virtual ligand screening approaches and high-throughput experimental screening, efforts would be undertaken to discover potential binders/inhibitors of these domains. Small-molecule inhibitors of this domain have potential applications in anti-viral treatments especially against viruses such as influenza and human immunodeficiency virus that have huge human and economic impact as well as in the treatment of autoinflammatory disorders.