Characterization of a Limb Autotomy Factor, LAFpro, that Suspends Molting in Crustaceans

9723576只大闸蟹和龙虾通过周期性地脱落坚硬的外骨骼来生长。这个过程被称为蜕皮，增加了组织生长的内部空间。成功的蜕皮需要器官系统的精确协调。在为蜕皮做准备的过程中，新外骨骼的前两层被形成，旧外骨骼的最内层被分解和吸收，而失去的行走的腿被再生。蜕皮是由位于眼柄和身体的内分泌器官产生的激素来调节的。然而，先前的研究表明，对蜕皮的控制更为复杂。如果在动物蜕皮前摘除再生的行走腿，蜕皮会推迟2-3周，这样就有时间让丢失的组织再生。PI最近表明，再生组织会产生一种因子，称为肢体自切因子--脱节因子(LAFPro)，它可以暂停陆蟹的蜕皮。该项目的主要目标是纯化和鉴定LAFPro。该提案包括两个具体目标：(1)建立暂停蜕皮的机制；(2)从再生组织中分离并鉴定可能的LAFPro。这项研究对于从整体上理解节肢动物生长的控制具有广泛的应用价值。通过组织再生暂停蜕皮并不是甲壳类动物所特有的。再生也会延缓各种昆虫的蜕皮。这表明了一种共同的机制。如果是这样的话，PI希望开发出控制害虫的全新策略。

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.