Regulation of Neurohormone Synthesis in Aplysia

神经激素负责控制生理和行为的不同方面，包括身体生长，饮食，性和生殖。 该项目的主要目标是了解控制神经肽激素合成的细胞机制，这些神经肽激素使用控制软体动物Aaplasia生殖的神经元。 PI实验室的早期研究表明，生殖神经内分泌袋细胞神经元（BCN）的电刺激导致大量神经肽产卵激素（ELH）的分泌。 据透露，电刺激上调ELH合成，以补充可释放的激素储存的钠和钙依赖性途径，这是独立于ELH分泌和动作电位放电。 此外，一种新的蛋白质合成途径，涉及一个特殊的代码ELH mRNA称为内部核糖体进入位点（IRES）在介导的电刺激上调特异性ELH合成的影响，在细胞中的非必需蛋白质的费用起着重要的作用。 这类似于病毒在感染后如何控制细胞中的蛋白质合成，并且不被认为在细胞系统中发挥生理作用。 本项目的目的是了解膜电激发，钠/钙离子流入袋细胞神经元，IRES激活ELH mRNA，和ELH合成之间的机制联系。 实验将利用膜电兴奋性的电生理监测和细胞内钙浓度的光学成像，以响应改变钠/钙通量的治疗，ELH合成的生物化学测量，以及分子生物学工具和光学成像的组合，以监测完整的神经组织中的活袋细胞神经元中的IRES激活。 从拟议的实验结果将导致完全新的结论控制细胞中的特定蛋白质合成。该项目为研究生和本科生提供了极好的培训机会，利用综合实验方法进行前沿研究

Neurohormones are responsible for controlling different aspects of physiology and behavior including body growth, eating, drinking, and sex and reproduction. The broad goal of this project is to understand cellular mechanisms controlling synthesis of a neuropeptide hormone using neurons that control reproduction in the mollusk Aplysia. Earlier studies from the PI's laboratory showed that electrical excitation of the reproductive neuroendocrine bag-cell neurons (BCNs) led to large amounts of secretion of the neuropeptide egg-laying hormone (ELH). It was revealed that electrical excitation upregulates ELH synthesis to replenish releasable stores of hormone by both sodium- and calcium-dependent pathways that are independent from both ELH secretion and action potential firing. Furthermore, a novel protein-synthetic pathway involving a special code on ELH mRNA called an internal ribosomal entry site (IRES) plays an important role in mediating the effects of electrical excitation on upregulating specifically ELH synthesis, at the expense of non-essential proteins in the cell. This is similar to how viruses control protein synthesis in cells following infection, and was not thought to play a physiological role in cellular systems. The aim of this project is to understand the mechanistic links between membrane electrical excitation, sodium/calcium ion fluxes into the bag cell neurons, IRES activation on ELH mRNA, and ELH synthesis. Experiments will utilize electrophysiological monitoring of membrane electrical excitability and optical imaging of intracellular calcium concentrations in response to treatments that alter sodium/calcium flux, biochemical measurement of ELH synthesis, and a combination of molecular biological tools and optical imaging to monitor IRES activation in living bag cell neurons in the intact Aplysia nervous tissue. The outcome from the proposed experiments will lead to entirely novel conclusions regarding the control of specific protein synthesis in cells. This project provides excellent training opportunities for graduate and undergraduate students embarking on cutting-edge studies using an integrative experimental approach