Genetic Regulation of Chlorophyll Synthesis in Higher Plants

植物光形态建成是一个由至少三个不同的光感受器控制的复杂的发育过程，涉及核和细胞器基因组中差异基因的表达。在这个过程中，一个特色的“问候”的地方。我们有兴趣了解高等植物中叶绿素形成的生化和分子遗传控制。我们已经鉴定了编码叶绿素生物合成途径三种酶的cDNA和/或克隆的基因组序列。这些酶或作为调节酶(如NADPH-原叶绿素氧化还原酶(PCR))或非限速步骤(如丙氨酸脱水酶(ALAD)、PBG脱氨酶(PBGD))参与这一途径，并被认为以正方式(ALAD)、负方式(PCR)或不受光(PBGD)影响的光敏色素介导的光调节。我们建议继续对编码这三种叶绿体蛋白的基因家族的结构、复杂性和组织进行表征。将从光照、叶绿体分化程度和细胞类型等方面分析单个家庭成员的表达特征。由于大量证据支持在高等植物中存在形成四吡咯的双重途径，我们将确定这些基因家族的个别成员是否产生定位于不同亚细胞隔室(叶绿体与胞质)的蛋白质，如果是这样的话，产生在不同亚细胞位置隔室的蛋白质的基因家族成员是否受到不同的调控程序。绿色植物产生叶绿素既是对环境中光线的反应，也是它们自身正常发育过程的一部分。对叶绿素生物合成的控制是复杂的，但人们对此知之甚少。这是一项旨在阐明这种控制的提议。*

Plant photomorphogenesis is a complex developmental process under the control of at least three distinct photoreceptors and involving differential gene expression in both nuclear and organellar genomes. During this process a characteristic "greeting" of place. We are interested in understanding the biochemical and molecular genetic control of chlorophyll formation in higher plants. We have identified cDNAs and/or cloned genomic sequences encoding three enzymes of the chlorophyll biosynthetic pathway. These enzymes participate in this pathway either as regulatory (e.g., NADPH- protochlorophyllide oxidoreductase (PCR) or non-rate-limiting steps (e.g., ALA-dehydratase (ALAD), PBG deaminase (PBGD) and are thought to be under phytochrome-mediated photoregulation either in a positive manner (ALAD), a negative manner (PCR), or to be unaffected by light (PBGD). We propose to continue our characterization of the structure, complexity, and organization of the gene families that encode these three chloroplast proteins. The expression characteristics of the individual family members will be analyzed with respect to light, extent of plastid differentiation and cell type. Since substantial evidence supporting the presence of a dual pathway for tetrapyrrole formation in higher plants exists, we will determine whether individual members of these gene families give rise to proteins localized in different subcellular compartments (chloroplastic versus cytosolic) and if so, whether members of a gene family giving rise to proteins compartmentalized in different subcellular locations are under different regulatory programs. Green plants produce chlorophyll both in response to light in their environment, and as part of their own normal developmental processes. The control of chlorophyll biosynthesis is complex, but poorly understood. This is a proposal to elucidate that control.***