Integrating Environmental Modulation, Osmosensitivity and Signaling in a Model Osmoreceptor

盐和水平衡的调节，或盐调节，是生物体中进行生命活动的分子正常功能的基础。这个项目解决了如何监测渗透平衡以及生物体如何对任何偏离最佳状态的情况作出反应的知识上的差距。通过渗透压受体细胞检测这种关键平衡的变化是激活确保恢复和维持渗透压平衡的机制的第一步。尽管如此，我们对受体细胞如何工作的理解一直受到其复杂结构和大脑，肾脏和其他器官中其他细胞之间排列的阻碍。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调节激素，罗非鱼是一种可以生活在淡水和盐度超过海水的非凡鱼类。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，这使得研究细胞如何调节变得容易。催乳素细胞已被证明具有渗透压受体的作用，通过改变催乳素分泌来恢复渗透压平衡，直接对渗透压变化做出反应。细胞大小的增加是激活增加催乳素分泌的细胞机制的触发器。本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在淡水和海水中生长的具有重要经济意义的食用鱼中受体细胞如何工作的基本理解。该项目将允许招聘，教育和培训高中，本科和研究生，包括那些代表性不足的少数民族从我们的多民族，文化多样性，大学和地区学校。将通过机构教育方案传达进展情况，并将在可供访问的网站上公布：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.