9723576 Mykles Crabs and lobsters grow by periodically shedding the hard exoskeleton. This process, called molting, increases interior space for tissue growth. Successful molting requires the precise coordination of organ systems. In preparation for molting, the first two layers of the new exoskeleton are formed and the innermost layers of the old exoskeleton are broken down and resorbed, while lost walking legs are regenerated. Molting is regulated by hormones produced by endocrine organs located in the eyestalks and body. Previous studies, however, indicate that control of molting is more complex. If a regenerating walking leg is removed before the animal molts, molting is delayed 2-3 weeks, which allows time for the lost tissue to be regenerated. The PI has recently shown that the regenerating tissue produces a factor, termed limb autotomy factor-proecdysis (LAFpro) that suspends molting in land crabs. The primary goal of this project is to purify and characterize LAFpro. The proposal consists of two specific aims: (1) establish the mechanism by which molting is suspended and (2) isolate and characterize putative LAFpro from regenerating tissues. This research has broad application to understanding the control of growth in arthropods as a whole. Suspension of molting by tissue regeneration is not unique to crustaceans. Regeneration also delays molting in a variety of insects. This suggests a common mechanism. If so, the PI hopes to develop entirely new strategies for controlling insect pests.
