Regulation of Nuclear Enzymes by Phytochrome

光敏色素对核酶的调节

• 批准号: 8716572
• 负责人: Stanley Roux
• 金额: $ 22.33万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-07-01 至 1991-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8716572&HistoricalAwards=false
• 关键词: Regulation; Nuclear; Enzymes; Phytochrome

This research seeks to determine the mechanisms by which the plant chromoprotein, phytochrome, photoreversibly regulates the activity of nuclear enzymes, especially that of a chromatin-associated nucleoside triphosphatase (NTPase). The research is designed to follow up and extend earlier findings which showed that red-light activated phytochrome could stimulate NTPase activity and nuclear protein phosphorylation in isolated pea nuclei and that Ca2+ and calmodulin played important roles in this response. It will be determined how much Ca2+ is required to support the NTPase stimulation and determine whether red light induces a change in the free ıCa2+! in the nuclear preparation. Phytochrome will be immunocytochemically localized in isolated nuclei to help evaluate where within the preparation it may be functioning. Binding of purified NTPase to DNA will be studied. Specific DNA sequences that are recognized by the enzyme will be sought. There is evidence the NTPase may be phosphorylated by a spermine-activated NII kinase. This kinase will be isolated and characterized to test whether it can phosphorylate the NTPase and whether its activation is promoted also by calcium.%%% Results expected from the proposed experiments should contribute significantly to an improved understanding of how light and Ca2+ can regulate nuclear metabolism, with possible implications also for models of how phytochrome regulates gene expression. The ultimate aim of this project is to understand how the plant photoreceptor, phytochrome, controls growth and development changes in plants. Current data favor the hypothesis that phytochrome achieves this control in many instances by inducing specific alterations of membrane properties in target cells.***//

这项研究旨在确定的机制， 植物色素蛋白，光敏色素，光可逆调节 核酶活性核酶的活性，尤指 染色质相关核苷三磷酸酶（NTR）。 的 研究旨在跟进和扩展早期的发现 这表明红光激活的光敏色素可以 刺激NTR活性和核蛋白磷酸化 在离体豌豆细胞核中，Ca ~（2+）和钙调素 在这方面发挥重要作用。 将决定如何 需要大量的Ca 2+来支持NTR刺激， 确定红光是否引起自由光的变化， Ca 2+！在核准备中。 光敏色素将是 免疫细胞化学定位于分离的细胞核， 评估它在准备过程中可能发挥作用的地方。 将研究纯化的NTR与DNA的结合。 具体 被酶识别的DNA序列将被 寻找。 有证据表明NTR可能被磷酸化 被精胺激活的NII激酶激活 这种激酶将是 分离并表征，以测试它是否可以 磷酸化NTR，以及其激活是否 也被钙所促进。% 从拟议的实验中预期的结果应该 有助于更好地理解 光和Ca ~（2+）可以调节核代谢， 光敏色素如何调节 基因表达。 该项目的最终目的是 了解植物感光细胞光敏色素是如何控制 植物的生长和发育变化。 当前数据有利于 假设光敏色素在许多情况下实现了这种控制， 通过诱导细胞膜的特异性改变， 目标单元格中的属性。*//