Meeting Abstract
Crustaceans express several classes of putative chemoreceptor proteins. These include variant ionotropic glutamate receptors (IRs) that have co-receptor IRs and tuning IRs that confer response specificity by forming heterotetrameric ion channels, Transient Receptor Potential (TRP) channels, Gustatory Receptors, and possibly others. The Caribbean spiny lobster, Panulirus argus, expresses over 200 IRs, 15 TRP channels from all TRP subfamilies, and 1 GR. However, the combinatorial expression pattern of these proteins in single chemoreceptor cells is not known for this or any crustacean species, limiting our understanding of how crustacean chemoreceptor systems encode chemical quality. We generated and analyzed seven single cell transcriptomes to provide a first view of the expression patterns of chemoreceptor proteins in olfactory receptor neurons (ORNs) in spiny lobsters. We found that all seven single-ORN transcriptomes contained two co-receptor IRs (IR25a, IR93a) and one TRP channel (TRPA1). In addition, single ORNs expressed 1–2 tuning IRs and also TRP channels belonging to subfamilies TRPA, TRPM, and TRPC. Tuning IRs included arthropod-conserved IRs, IR40a and IR75, as well as species-specific IRs. We did not detect two other co-receptor IRs, IR8a or IR76b, in the single-ORN transcriptomes despite their presence in the transcriptome of the olfactory organ. Our results yield an initial view of combinatorial expression of co-receptor IRs, tuning IRs, and TRP channels in ORNs from this decapod crustacean, where ORNs may express different subsets of receptor molecules compared to other types of chemoreceptor neurons.
