Signaling Mechanisms in Custacean Molting Gland

甲壳类动物的生长需要定期脱落外壳，这一过程称为蜕皮，由眼柄中的神经分泌中心控制。该复合体分泌蜕皮抑制激素（MIH），其抑制蜕皮激素蜕皮激素的产生，蜕皮激素是由位于体内的一对蜕皮腺（Y器官或YO）分泌的蜕皮类固醇。因此，似乎蜕皮是由血液中MIH的减少触发的，这刺激蜕皮腺合成和分泌蜕皮激素。据认为，MIH与膜受体的结合导致蜕皮激素合成酶的环核苷酸依赖性抑制。在热带陆地蟹中克隆了可能在MIH信号传导中起作用的五个基因：一氧化氮合酶（NOS），三种鸟苷酸环化酶（GC）和MIH。该项目的具体目标是确定MIH信号转导途径，确定NOS和GCs的调节，并确定MIH与其他相关激素之间的相互作用。了解甲壳类动物蜕皮和生长的激素调节对于管理渔业、发展有效的水产养殖做法和减轻内分泌干扰物等污染物的潜在影响至关重要。尽管付出了巨大的努力，但人们对MIH信号通路知之甚少。膜受体的身份和其他组件的途径仍然未知。现在，表达大量活性MIH的方法是可用的，MIH信号通路可以阐明，并可以确定与其他激素和污染物的潜在相互作用。一氧化氮的潜在作用构成了一个全新的和令人兴奋的调查路线。该项目将培养一名博士后、研究生和4-6名本科生掌握先进的分子生物学技术，包括定量聚合酶链反应（PCR）。

Growth in crustaceans requires the periodic shedding of the shell, a process called molting, which is controlled by a neurosecretory center in the eyestalks. The complex secretes molt-inhibiting hormone (MIH) that inhibits production of the molting hormone ecdysone, an ecdysteroid secreted by a pair of molting glands (Y-organs or YOs) located in the body. Thus it appears that molting is triggered by a reduction in MIH in the blood, which stimulates the molting glands to synthesize and secrete ecdysone. It is thought that binding of MIH to a membrane receptor results in a cyclic nucleotide-dependent inhibition of ecdysone-synthesizing enzymes. Five genes were cloned in the tropical land crab that may play a role in MIH signaling: nitric oxide synthase (NOS), three guanylyl cyclases (GCs), and MIH. The specific aims of the project are to determine the MIH signal transduction pathway, determine the regulation of NOS and GCs, and determine the interaction, if any, between MIH and other related hormones. Understanding the hormonal regulation of crustacean molting and growth is essential to manage fisheries, develop effective aquacultural practices, and mitigate potential effects of pollutants, such as endocrine disruptors. Despite intense effort, very little is known about the MIH signaling pathway. The identity of the membrane receptor and other components of the pathway remain unknown. Now that methods to express large amounts of active MIH are available, the MIH signaling pathway can be elucidated and potential interactions with other hormones and pollutants can be determined. The potential role of nitric oxide constitutes an entirely novel and exciting line of investigation. The project will train a postdoc, graduate student, and 4-6 undergraduates in advanced molecular biological techniques, including quantitative polymerase chain reaction (PCR).