Characterization of a Water-Borne Egg-Laying Synchronization Pheromone

University Of Texas Medical Branch At Galveston, Galveston TX

Investigators

Abstract

Peptide pheromonal communication in the marine environment is an ancient form of chemical communication. In the marine snail Aplysia californica, egg-laying individuals secrete a peptide pheromonal attractant ("attractin") that attracts other Aplysia to the source of the pheromone, resulting in the formation of mating and egg-laying aggregations. Strikingly, Aplysia californica attractin also attracts members of other Aplysia species as well. A conserved stretch of 7 amino acids is found in the attractin sequences of five different species of Aplysia, suggesting that this region is important for activity. One major goal of this study is to determine whether this region is critical for attraction activity. This will be accomplished by: 1) testing mutant attractins in which charged residues in the conserved region are mutated; and 2) synthesizing and testing peptides corresponding to conserved regions of attractin. A second goal is to purify, characterize, clone, and express a second candidate pheromone that is secreted during Aplysia egg laying. When an actively egg-laying Aplysia is placed in an aquarium containing non-laying Aplysia, a higher frequency of egg-laying occurs among non-laying animals, suggesting that an egg-laying synchronization pheromone is secreted by egg layers. The candidate pheromone will be purified from eluates of egg cordons, chemically characterized, cloned, and recombinant pheromone tested to determine whether it triggers the neuroendocrine bag cells to release egg-laying hormone into the blood to stimulate egg release. The results of this study will be of interest to investigators working on chemical communication, peptide pheromones, and the regulation of reproductive behavior in the aquatic environment. They will provide important information about the attractin family and their receptors, and will open the door to studies of the olfactory system. This research will also provide educational and training opportunities for postdoctoral, graduate, undergraduate, and high school students.