Genetic Regulation of Chlorophyll Synthesis in Higher Plants

植物光形态发生是一个复杂的发育过程，在至少三种不同的光感受器的控制下，涉及核和细胞器基因组中的差异基因表达。在这一过程中，有一个地方特有的“问候”。我们对了解高等植物叶绿素形成的生化和分子遗传控制感兴趣。我们已经确定了编码叶绿素生物合成途径的三种酶的cdna和/或克隆的基因组序列。这些酶参与这一途径，要么作为调控（如NADPH-原叶绿内酯氧化还原酶（PCR）），要么作为非限速步骤（如ala -脱水酶（ALAD）， PBG脱氨酶（PBGD）），被认为在光敏色素介导的光调控下，要么以积极的方式（ALAD），要么以消极的方式（PCR），要么不受光的影响（PBGD）。我们建议继续我们的结构，复杂性和编码这三种叶绿体蛋白的基因家族的组织表征。个体家族成员的表达特征将根据光照、质体分化程度和细胞类型进行分析。由于存在大量证据支持高等植物中四氟咯形成的双重途径，我们将确定这些基因家族的单个成员是否产生定位于不同亚细胞区室（叶绿体与细胞质）的蛋白质，如果是这样，一个基因家族的成员是否在不同的亚细胞位置产生区隔化的蛋白质是在不同的调控程序下。绿色植物产生叶绿素既是对环境光的反应，也是它们自身正常发育过程的一部分。叶绿素生物合成的控制是复杂的，但知之甚少。这是一个阐明这种控制的建议

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.***