Regulation of Proline Synthesis in Osmotic Response

研究的重点将是海洋桡足类虎脚类对环境盐度变化的生物化学和分子机制。像许多其他物种一样，这种物种在细胞内积累了高浓度的脯氨酸，这是一种非必需氨基酸。高等生物体对渗透胁迫的反应机制尚不清楚。前人的工作表明，在谷氨酸和脯氨酸之间的前两步途径中存在一个诱导Pro合成的调控位点，目前的工作将集中在这一途径上。这项拟议工作的目标是阐明这种调控的分子机制，并确定为什么这种调控在一些种群间杂交中失败。主要目的是：(1)分离(克隆)编码Pro合成途径中前两种酶的基因，(2)确定这些基因在渗透反应过程中的正常调节模式，(3)从生化水平筛选对Pro合成的异常调节的种群间杂交系，以及(4)利用克隆的基因作为探针来确定在Pro合成过程中杂种破坏的机制。

Research will focus on the biochemical and molecular mechanisms by which the marine copepod Tigriopus californicus responds to changes in environmental salinity. This species, like many others, is known to accumulate high intracellular concentrations of proline, a non- essential amino acid. The mechanisms regulating proline synthesis in response to osmotic stress in higher organisms remain to be determined. Previous work has shown that one regulatory site for induction of proline synthesis lies within the first two steps of the pathway between glutamate and proline; the current work will concentrate on this pathway. The goals of the proposed work are to elucidate the molecular mechanisms underlying this regulation and to determine why such regulation fails among some interpopulation hybrids. Primary objectives are: (1) to isolate (clone) the genes encoding the first two enzymes in the proline synthesis pathway, (2) to determine the normal pattern of regulation of these genes during osmotic response, (3) to screen interpopulation hybrid lines for aberrant regulation of proline synthesis at the biochemical level, and (4) to use the cloned genes as probes for determining the mechanism underlying hybrid breakdown in proline synthesis.