Neuroendocrine systems of cnidarians: characterization and roles in reproduction and development

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My research program aims at understanding the functional organization and molecular basis of neuro-endocrine pathways in cnidarians. As cnidarians are the lowest invertebrates in which nervous systems were identified, this research offers opportunities to compare neurotransmitter/neurohormone systems in metazoans and to test hypotheses of evolutionary conservation of chemical signaling functions. Our experimental model of choice is the sea pansy (Renilla koellikeri), an octocorallian anthozoan which is easily maintained in the laboratory and lends itself readily to experimental manipulation. An hexacorallian, the staghorn Acropora millepora, will also be used through a collaborative effort. The main objectives of this proposal are: (1) To pursue our current efforts to clone and express products of genes encoding neurally related signaling molecules (amine transporters and biosynthesis enzymes, G protein-coupled receptors) in order to understand the early evolution of these important participants in neurotransmitter/neurohormone signaling. (2) To pursue our investigations on the neuroendocrinology of reproduction and development in both the sea pansy and in corals, looking into the possible involvement of sex steroids, retinoic acid and other chemical regulators and mapping the expression of putative neural regulatory genes during development and sexual maturation. (3) To investigate the effects of signaling molecules on re-differentiating sea pansy neurons in culture and the expression of signaling markers during neuronal differentiation. These investigations are expected to contribute significant advances in the field of cnidarian neuro-endocrinology, especially regarding the phylogenetic ancestry of neuro-endocrine mediators. In addition, an understanding of the neuro-endocrinological basis of reproduction control and development has potential fallouts in the management of ecologically important cnidarians such as reef corals.