Molecular Analysis of Maize Antocyanin Biosynthesis

其产物在生化途径中共同作用的基因的协调表达是许多生物调控生物学的焦点。本研究的目的是表征控制玉米花青素色素生物合成途径中几个基因转录表达的顺式和反式作用因子。花青素的合成需要结构基因和调控基因的产物。遗传和分子分析的结果表明，两个调节基因C1（彩色糊粉素-1）和Pl（紫色植物）是正向反式激活因子，它们分别在不同组织中发挥类似的调节功能，控制仁和植物的色素沉着。该建议旨在评估C1或P1与它们控制转录的基因之间的分子相互作用。玉米组织核提取物将用于dna酶I足迹实验，以鉴定克隆靶基因中的顺式作用元件。将进行体外和体内试验，以确定C1和P1基因产物是否能够特异性结合靶元件和/或激活转录。分子遗传学方法将用于探索C1和P1本身的调节，目的是确定介导这些调节基因的组织特异性表达的其他因素。玉米花青素生物合成途径一直是玉米遗传研究的焦点，主要是因为易于检测颜色突变体。该研究将加深我们对结构蛋白编码基因在植物中表达调控的认识。

The coordinate expression of genes whose products act jointly in a biochemical pathway is a focal point of regulatory biology in many organisms. The objective of the proposed research is to characterize cis- and trans-acting factors that control the transcriptional expression of several genes in the biosynthetic pathway for anthocyanin pigments in maize. Anthocyanin synthesis requires the products of both structural and regulatory genes. The results of genetic and molecular analyses implicate two of the regulatory genes, C1 (Colored aleurone-1) and Pl (Purple plant) as positive trans-activators that perform analogous regulatory functions in distinct tissues to control pigmentationin the kernel and the plant, respectively. This proposal is aimed at evaluating the molecular interactions between C1 or P1 and the genes whose transcription they control. Nuclear extracts from maize tissues will be used in DNase I footprinting experiments to identify cis-acting elements in cloned target genes. Both in vitro and in vivo assays will be performed to determine if the C1 and P1 gene products are capable of specifically binding target elements and/or activating transcription. Molecular genetic approaches will be used to explore the regulation of C1 and P1 themselves with the goal of identifying other factors that mediate the tissue-specific expression of these regulatory genes. The pathway for anthocyanin biosynthesis in maize has been the focus of many of the extensive genetic studies in corn, primariy because of the ease of detecting color mutants. This study will deepen our insight into how genes encoding structural protein are regulated in their expression in plants.