Integrating Environmental Modulation, Osmosensitivity and Signaling in a Model Osmoreceptor

盐和水平衡的调节，或渗透调节，是在生物体中进行生命活动的分子正常功能的基础。该项目解决了如何监测渗透平衡以及生物体如何应对任何偏离最佳状态的知识差距。渗透受体细胞检测到这种关键平衡的变化是激活确保渗透平衡恢复和维持的机制的第一步。然而，渗透受体细胞在大脑、肾脏和其他器官中的复杂结构和排列阻碍了我们对渗透受体细胞如何工作的理解。这使得开发有用的实验方法变得极其困难。罗非鱼的催乳素细胞解决了这个问题。催乳素是罗非鱼体内的一种渗透调节激素，罗非鱼是一种非凡的鱼类，可以生活在淡水和高于海水的盐度中。与哺乳动物不同，罗非鱼的催乳素细胞在脑垂体中排列成几乎均匀的团块，这使得研究细胞是如何被调节的变得容易。催乳素细胞已被证明作为渗透受体，通过改变催乳素分泌来直接响应渗透变化，从而恢复渗透平衡。细胞大小的增加是触发细胞机制增加催乳素分泌的触发器。该项目将研究细胞大小如何控制编码催乳素的基因的活性/表达。预计这项工作将增加对渗透受体细胞如何在淡水和海水中生长的具有重要经济意义的食用鱼中起作用的基本理解。该项目将允许招收、教育和培训高中生、本科生和研究生，包括来自我们多民族、多元文化的大学和地区学校中代表性不足的少数民族学生。进展将通过机构教育项目传达，并将公布在一个公众可访问的网站上：http://www.hawaii.edu/himb/faculty/grau.html。

The regulation of salt and water balance, or osmoregulation, is fundamental to the proper function of the molecules that carry on the business of life in living organisms. This project addresses the gap in knowledge of how osmotic balance is monitored and how an organism responds to any deviation from the optimal state. Detection of a change in this critical balance by osmoreceptor cells is the first step in activating the mechanisms which ensure osmotic balance is restored and maintained. Nevertheless, our understanding of how osmoreceptor cells work has been hindered by their complex structure and arrangement among other cells in the brain, kidney and other organs. This makes it extremely difficult to develop useful experimental approaches. The prolactin cell of the tilapia solves this problem. Prolactin is an osmoregulatory hormone in tilapia, a remarkable fish that can live in fresh water and in salinities exceeding that of seawater. Unlike mammals, prolactin cells in tilapia are arranged into a nearly homogeneous mass in the pituitary gland making it easy to study how the cell is regulated. Prolactin cells have been shown to function as osmoreceptors that respond directly to osmotic changes by altering prolactin secretion which restores osmotic balance. An increase in cell size is the trigger that activates cell mechanisms that increase prolactin secretion. This project will investigate how cell size controls the activity/expression of the gene that encodes prolactin. It is anticipated that this work will increase the fundamental understanding of how osmoreceptor cells work in an economically important food fish grown in fresh water and seawater. This project will allow the recruitment, education, and training of high school, undergraduate and graduate students, including those of under-represented minorities from within our multi-ethnic, culturally diverse, University and area schools. Progress will be conveyed via institutional educational programs and will be posted on a publically accessible website: http://www.hawaii.edu/himb/faculty/grau.html.