P2.24 Friday, Jan. 4 In search of the sea urchin nose: The molecular basis for chemoreception in S. purpuratus CHURCHER, A.M.*; TAYLOR, J.S.; Univ. of Victoria, Victoria BC; Univ. of Victoria, Victoria BC email@example.com
Chemical cues found in the environment provide organisms with critical information about their surroundings and often play an important role in behavior, development and physiology. Chemosensory systems are well studied in the worm, the fly and several vertebrates but are not well characterized in the invertebrates from the deuterostome lineage. To fill this void and to provide insight into the evolution of vertebrate sensory systems, we investigated chemoreception in the sea urchin, Strongylocentrotus purpuratus. To identify chemoreceptor genes, the sea urchin protein predictions were surveyed for the presence of sequence motifs found in vertebrate chemoreceptors. 192 candidate genes were identified using this approach many of which, much like the chemoreceptor genes found in other species, are single exon genes that are tandemly arrayed. The amino acid motifs shared by sea urchin and vertebrate chemoreceptors will help to define vertebrate gene families and may clarify ancestral relationships among G protein-coupled receptors. These genes also provide an important reference point for identifying chemoreceptors in other deuterostome genomes such as the tunicate and amphioxus. To determine tissue-specific expression patterns, we used reverse transcription and PCR. Several of these genes are expressed in the tube feet and pedicellaria suggesting they may play a role in environmental monitoring. Unlike many vertebrate chemosensory structures, tube feet and pedicellaria are located all over the sea urchin body suggesting this organism relies on a decentralized system for sensory perception.