EXPRESSION OF C4 GENES IN DEVELOPMENT OF MAIZE LEAF CELL

该项目的长期目标是了解 玉米叶片细胞分化的分子机制 分化和形态发生。我们对C4途径的研究 玉米叶片中基因及其细胞特异性表达的研究 研究表明，细胞间的相互作用、细胞特异性 利用小基因家族成员，以及位置和谱系 信息在分化两个主要叶细胞中的作用 类型：束鞘(BS)和叶肉(M)。这项提议旨在 为了确定这些现象的分子基础，用 以下是具体目标： (1)找到顺式和反式作用的监管要素 控制细胞特异性和位置依赖的基因表达 对于依赖NADP的苹果酸酶(ME)、依赖NADP的苹果酸 脱氢酶(MDH)、磷酸烯醇式丙酮酸羧化酶(PEPCase)、 和他们的管家同行。 (2)获得并比较两种光合作用的DNA序列 ME和MDH基因的(叶)和管家(所有组织)成员 并比较ME、MDH和其他C4的序列 以同样的方式调节的途径基因，以及 (3)探讨BS和M细胞的依赖性。 细胞位置、细胞谱系和局部细胞的分化 利用C4基因作为细胞标记在叶片中的相互作用 RNA和蛋白质的原位研究，叶模式突变的分析， 以及辐照或培养的叶原基的分析。 我国玉米叶片培养方法的最新进展 原基与离体芽再生植株 APICS将允许采用新的方法来研究花纹 玉米中的基因表达，包括细胞标记。我们将依靠 关于先前制备的C4抗体、cDNAs和基因探针 C4基因功能与叶片细胞分化的研究。

The long term objective of this project is to understand the molecular mechanisms by which the maize leaf undergoes cellular differentiation and morphogenesis. Our studies of C4 pathway genes and of their cell-specific expression during maize leaf development have indicated that cell interactions, cell-specific use of small gene family members, and both positional and lineage information play roles in the differentiation two major leaf cell types, bundle sheath (BS) and mesophyll (M). This proposal seeks to determine the molecular basis of these phenomena, with the following specific aims: (1) to find the cis- and trans-acting regulatory elements that control cell-specific and position-dependent expression of genes for NADP-dependent malic enzyme (ME), NADP-dependent malate dehydrogenase (MDH), phosphoenolpyruvate carboxylase (PEPCase), and their housekeeping counterparts. (2) to obtain and compare DNA sequences for both photosynthetic (leaf) and housekeeping (all tissue) members of ME and MDH gene families and to compare sequences of ME, MDH, and other C4 pathway genes regulated in the same way, and (3) to investigate the dependence of BS and M cell differentiation on cell position, cell lineage, and local cell interactions in the leaf, using C4 genes as cell markers in in situ RNA and protein studies, analysis of leaf pattern mutants, and analysis of irradiated or cultured leaf primordia. Our recent development of methods for culture of maize leaf primordia and the regeneration of plants from isolated shoot apices will permit novel approaches to the study of patterned gene expression in maize, including cell-tagging. We will rely on previously prepared C4 antibody, cDNA, and gene probes for the studies on C4 gene function and leaf cellular differentiation.