HEYLAND, Andreas; BODNAROVA, M; MOROZ, LL; Whitney Laboratory, Center for Excellence in Genomic Sciences, University of Florida, St. Augustine, FL; Whitney Laboratory, Center for Excellence in Genomic Sciences, University of Florida, St. Augustine, FL; Whitney Laboratory, Center for Excellence in Genomic Sciences, University of Florida, St. Augustine, FL: Thyroid hormone like metabolism and function in complex life histories

Thyroid Peroxidase (TPO) is critical for thyroid hormone synthesis in the vertebrate thyroid gland. We now cloned TPO orthologs from two non-chordate invertebrates: the sea urchin Lytechinus variegatus (LvTPO) and the mollusk Aplysia californica (AcaTPO) and report here on the expression patterns of these genes. Our preliminary data indicate that AcaTPO and LvTPO are expressed in larval and adult nervous systems. If, in fact, these TPOs are involved in thyroid hormone synthesis in these species, this would suggest a novel mechanism of thyroid hormone like signaling and synthesis. Previously published and unpublished data suggest a critical role of thyroid hormone like compounds in echinoderm larval development and metamorphosis. While some echinoderm species depend primarily on hormone from exogenous sources, i.e. phytoplankton, others have the ability to synthesize these compounds endogenously. Our new data suggest that echinoderm larvae use TPO to accomplish this task. Moreover, the presence of TPO in a non-chordate deuterostome and a protostome suggests a much wider evolutionary distribution of this hormone synthesizing enzyme then previously thought.