9408342 Hopkins Crustaceans regenerate new walking legs when old ones are lost or injured. Ecdysteroids (the invertebrate steroid hormones) which control growth in virtually all arthropods also influence the special kind of growth involved in regeneration. The research proposed here will investigate the role of these steroids in leg regeneration in the crab, Uca pugilator. Since regeneration in crabs involves both cellular differentiation and anabolic activities, this research will yield new insights into the molecular controls of these two very different events. Using our recently isolated DNA probe for the ecdysteroid receptor, Dr. Hopkins will look at the patterns of receptor expression during regeneration and the structural/functional relationships between steroid hormones, other growth-affecting compounds (such as the retinoids), and their receptors. Because steroid receptors of invertebrates are so similar to those of higher vertebrates, the data generated by this research should provide a better understanding of how steroids, in general, control and coordinate the complicated phenomena of growth. ***
