IDENTIFYING CYTOPLASMIC NUCLEIC ACID SENSORS, DHX9 AND DDX3, IN RAINBOW TROUT
Shanee Herrington-Krause, Wilfrid Laurier University
Shanee L. Herrington-Krause, Sarah J. Poynter, Stephanie J. DeWitte-Orr
Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, CANADA
Innate immunity constitutes the first line of defense against virus infections. Viruses produce nucleic acids, both RNA and DNA, during genome replication and transcript synthesis. These nucleic acids are foreign to the cell and are sensed by pattern recognition receptors, based on their type (RNA or DNA), their strandedness (ss or ds) and their location (endosomal, extracellular or cytoplasmic). When a viral nucleic acid is in the wrong compartment (ex. dsDNA in the cytoplasm), they are sensed by pattern recognition receptors (PRRs) which activate signalling cascades that culminate in the production of type I interferons (IFNs) and the induction of an antiviral state. Cytoplasmic RNA sensors, such as RIG-I and MDA5, have begun to be characterized in several fish species, but almost nothing is known of cytoplasmic DNA sensors (CDSs) in fish. To this end, two CDSs were cloned from the rainbow trout gonadal cell line RTG2. Both CDSs are ATP dependent RNA helicases that in mammals function as innate immune sensors to initiate an antiviral state via the IFN pathway during a virus infection. In this study the novel rainbow trout DHX9 and DDX3 sequences were compared to known vertebrates sequences to identify conserved protein domains, intron/exon structures and phylogeny. Theirresponses to viral infection are currently under investigation. Knowledge of CDSs in rainbow trout will aid in a better understanding of innate antiviral immunity in this commercially and economically important fish species.