CHARACTERIZATION AND EVOLUTION OF GTPASES OF IMMUNITY ASSOCIATED PROTEINS (GIMAP) IN CNIDARIANS AND DINOFLAGELLATES

Corals are critical to the coral reef ecosystem in that they provide shelter for many types of marine life, which in turn provides tourism to many countries and supports various fishing industries. Currently, coral disease is a major threat to coral reefs, yet very little is currently known about the cellular pathways it impacts. One group of proteins that could play a role in the cnidarian immune response are GTPases of immunity associated proteins (GIMAPs). In vertebrates, GIMAPs are known to regulate the fate of developing lymphocytes, potentially by associating with apoptotic factors. However, cnidarians do not have lymphocytes, and therefore the function of GIMAPs remains unclear. GIMAPs were previously characterized in the coral Acropora millepora, but were not found in the genome of the anemone Nematostella vectensis, making the phylogenetic distribution of GIMAPs a topic of interest. In this study, we utilized genomic and transcriptomic databases to search for GIMAPs in both cnidarians and dinoflagellates to better understand the evolutionary history of this gene family. The sequence searches yielded a multitude of GIMAP-like sequences in both cnidarians and dinoflagellates. In addition, two different forms of GIMAPs were discovered within cnidarians, where some species possess both, others have one, and some have none. This represents the first characterization of GIMAP sequences in dinoflagellates. Overall, this work provides a greater understanding of the cnidaran immune repertoire, and also the evolutionary history of GIMAPS in both basal metazoans and protists