Signaling Mechanisms in Custacean Molting Gland

甲壳类动物的生长需要定期蜕壳，这一过程被称为蜕皮，由眼柄中的神经分泌中心控制。这种复合体分泌蜕皮抑制激素（MIH），抑制蜕皮激素蜕皮激素的产生，蜕皮激素是一种蜕皮类固醇，由位于体内的一对蜕皮腺（y器官或yo）分泌。因此，蜕皮似乎是由血液中MIH的减少引发的，MIH刺激蜕皮腺合成和分泌蜕皮激素。据认为，MIH结合膜受体导致环核苷酸依赖性的抑制蜕皮激素合成酶。在热带陆蟹中克隆了5个可能参与MIH信号通路的基因：一氧化氮合酶（NOS）、三种冠酰环化酶（GCs）和MIH。该项目的具体目的是确定MIH信号转导通路，确定NOS和GCs的调控，以及确定MIH与其他相关激素之间是否存在相互作用。了解甲壳类动物蜕皮和生长的激素调节对于渔业管理、开发有效的水产养殖方法以及减轻污染物（如内分泌干扰物）的潜在影响至关重要。尽管付出了巨大的努力，但我们对MIH信号通路知之甚少。膜受体和该途径的其他成分的身份仍然未知。现在有了表达大量活性MIH的方法，可以阐明MIH信号通路，并确定其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、令人兴奋的研究方向。该项目将培养1名博士后、1名研究生和4-6名本科生，研究包括定量聚合酶链反应（PCR）在内的先进分子生物学技术。

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).