How Do Sea Slugs Smell? A Molecular Approach to Investigating Olfaction in a Nudibranch

Presenter: Tess Thattacherry

Faculty Sponsor: Paul Katz

School: UMass Amherst

Research Area: Neuroscience and Cognitive Science

Session: Poster Session 5, 3:15 PM - 4:00 PM, 163, C17

ABSTRACT

Tess Thattacherry, Emma Johnson, Jorge L. Pérez-Moreno, Paul S. Katz                                                                                                          

Our sense of smell starts with molecular receptors expressed by neurons in our noses. The organization of olfactory systems has been intensely studied in vertebrates and in insects. However, little is known about the molecular basis for this sense in molluscs. We are studying the neuronal signaling pathways in the nudibranch mollusc, Berghia stephanieae. This can give us insights into evolutionary patterns, and help us infer structural or functional constraints on how olfactory signals are processed. Berghia has olfactory organs called rhinophores that detect chemicals using G-protein coupled receptors (GPCRs). Odorants activate specific GPCRs, triggering G-proteins that start a chain reaction resulting in a neuron firing. Different types of G-proteins, most significantly Gα, differ according to the function of the receptor. Identifying Gα variants, like the smell-associated Gαo, is thus a convenient way to observe where olfactory signals are being transmitted. We reconstructed a phylogenetic tree of these proteins across molluscs using a custom database of molluscan genes, which may indicate evolutionary relationships between G-proteins in Berghia and other molluscs. Current work is focused on identifying the Gαo proteins that could be present in B. stephanieae, which will allow us to use modern molecular techniques, such as single-cell RNA sequencing data and HCR with microscopy, to identify and classify the neurons and genes associated with olfaction. By characterizing olfactory neurons in these molluscs, we can provide a new view of olfactory-related proteins in this emerging study system for neuroscience.

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