Biogenesis of Peroxisomes in Plants

植物过氧化物体生物发生的三个不同方面：(1)油籽乙氧基体膨胀膜获得蛋白质和脂肪的途径是细胞器生物发生的组成部分。这一假设将得到验证，即脂体有助于油籽乙氧基体的分化；(2)将确定苹果酸合成酶、异柠檬酸裂解酶和过氧化氢酶在培养猴肾和选定的植物细胞中识别和体内转移的参数和条件；(3)将继续研究成熟种子和萌发种子中过氧化氢酶同工酶从乙氧体向叶型过氧化物体转换过程中的调控和发育表达规律，以及异柠檬酸裂解酶和苹果酸合成酶在乙氧体分化过程中的调控和发育表达规律。胚胎培养系统的可获得性有望提供一种独特的手段来帮助解决成熟种子中的调控模式。几乎所有真核细胞中都存在过氧化体，根据它们所在的细胞类型，它们执行各种基本的代谢功能。它们不能合成自己的磷脂或蛋白质，因此依赖于负责其生物发生的选择性和复杂的细胞内运输机制。这项建议的目标是研究选定的、相互关联的过氧化物体生物发生方面的分子和生化基础；重点将放在棉籽乙氧基糖体上。

Three different aspects of plant peroxisome biogenesis will be pursued: (1), the means by which the expanding membrane of oilseed glyoxysomes acquires its protein and lipid is an integral part of the organelle biogenesis. The hypothesis will be tested that lipid bodies contribute membrane lipid to differentiating oilseed glyoxysomes; (2), parameters and conditions necessary and/or sufficient for recognition and tranlocation in vivo of malate synthase, isocitrate lyase and catalase into peroxisomes of cultured monkey kidney and selected plant cells will be determined; (3) studies will continue on deciphering patterns of regulation and developmental expression of catalase isoforms during the changeover from glyoxysomes to leaf-type peroxisomes, and of isocitrate lyase and malate synthase during glyoxysome differentiation in maturing and germinated seeds. The availability of an embryo culture system is expected to provide a unique means to help resolve regulation patterns within maturing seeds. Peroxisomes occur in virtually all eukaryotic cells, conducting a variety of essential metabolic functions depending on the cell type in which they reside. They are not capable of synthesizing their own phospholipids or proteins, and are therefore dependent upon the selective and complicated intracellular trafficking mechanisms responsible for their biogenesis. The objectives of this proposal are to examine the molecular and biochemical bases of selected, interrelated aspects of peroxisome biogenesis; the emphasis will be on cottonseed glyoxysomes.