ELUCIDATION OF A HORMONAL RESPONSE PATHWAY

植物激素的作用机制尚未完全了解。一 部分转导途径涉及改变水平的机制 生理反应所需的基因产物。的 这种酶诱导的基因表达的调节在一定程度上受到控制 在转录水平上。本提案将侧重于 表征编码结合至细胞核的核蛋白的基因， 植物启动子的区域，这些区域在植物启动子的功能中是重要的。 植物激素脱落酸（阿坝）对基因表达的调控。我们 已经分离了两个基因的cDNA克隆，这两个基因的蛋白质与不同的 小麦ABA调控启动子（Em）的功能区。富含at Em启动子的区域似乎刺激了Em启动子的表达水平。 一种独立的方式。识别这种结合蛋白的 区域具有植物高迁移率族（HMG）核的性质 蛋白Em启动子的不同区域包含阿坝反应 元件，并结合一种不同的蛋白质， 具有亮氨酸拉链基序的转录调节蛋白。 实验提出：表征每个基因和隔离其他 他们的家庭成员;遵循每个基因的表达在不同的 组织中阿坝的水平和Em的表达;定义 蛋白质/DNA相互作用的特异性结合区域;以及，测试 蛋白质的功能，就其可能的作用， 阿坝反应途径，使用植物和酵母在体内测定系统。所有 这些方法的结果应鉴定中间体 并帮助阐明这种阿坝反应是否 途径类似于激素调节基因表达在其他 真核生物

The mechanism of action of phytohormones is not completely understood. A part of the transduction pathway involves mechanisms that alter the levels of gene products that are required for the physiological response. The regulation of this hormone-induced gene expression is in part controlled at the level of transcription. This proposal will focus on the characterization of the genes coding for nuclear proteins that bind to regions of plant promoters that are functionally important in the regulation of gene expression by the phytohormone abscisic acid (ABA). We have isolated cDNA clones of two genes whose proteins bind to different functional regions of an ABA-regulated promoter (Em) from wheat. An AT-rich region of the Em promoter appears to stimulate the level of expression in a hormone-independent manner. The binding protein that recognizes this region has the properties of a plant high mobility group (HMG) nuclear protein. A different region of the Em promoter contains an ABA response element and binds a different protein which has the sequence of a transcriptional regulatory protein possessing a leucine zipper motif. Experiments are proposed to: characterize each gene and isolate other members of their families; follow the expression of each gene in different tissues with respect to the levels of ABA and expression of Em; define the specific binding regions of the protein/DNA interaction; and, test the functionality of the proteins with respect to their possible roles in the ABA response pathway by using plant and yeast in vivo assay systems. All of these approaches should result in the identification of intermediates in the ABA response chain and help elucidate whether this ABA response pathway is analogous to hormonal regulation of gene expression in other eukaryotes.