AUXIN SIGNALING APPARATUS

植物激素生长素，典型的吲哚-3-乙酸（IAA）调节 植物生长和发育的各个方面如细胞分裂， 维管分化，侧根形成，顶端优势， 形态发生、肿瘤发生、向性，并且通常被认为是 负责调节植物细胞生长。尽管重要的是 生长素在植物发育中的主要分子机制 行动不明。 过去10年积累的实验证据表明， 激素在转录水平上快速起作用（3-5分钟）。分子， 利用早期生长素诱导的生物化学、遗传和结构研究 本文提出了来自豌豆（Pisum sativum）（豌豆）和拟南芥的基因，以获得 深入了解：（一）信号装置的分子细节 负责其转录激活;和（ii）的作用 它们编码的多肽在植物生长和发育中的作用。具体 该提案的目的是： 1.分离与生长素相互作用的转录因子 利用分子生物学技术， 遗传（酵母中的“单杂交系统”）或生物化学（DNA亲和性 色谱法）方法。克隆和结构表征基因组 编码该因子的序列并决定其表达 植物发育过程中的特征。 2.分离拟南芥中影响基因表达的突变， 通过使用已经构建的表达GUS的拟南芥系， 这些领域。通过定位克隆进行其中一种突变。 3.对PS-IAA 4/5样蛋白进行生物化学表征， 在假定的β-α-α DNA结合处结合的DNA序列 这些核短寿命蛋白的结构域。分离出基因组序列 包含结合位点（靶基因/晚期基因）。 阐明生长素作用的主要机制是至关重要的 在植物科学中的重要性。了解生长素如何控制细胞 生长、分生组织活动、木质发生等将允许工程化 具有改进的性质和品质的植物物种。

The plant hormone auxin, typified by indole-3-acetic acid (IAA) regulates various aspects of plant growth and development such as cell division, vascular differentiation, lateral root formation, apical dominance, morphogenesis, oncogenesis, tropisms, and is generally considered to be responsible for regulating plant cell growth. Despite the importance of auxin in plant development, the primary molecular mechanism of auxin action is unknown. Experimental evidence accumulated in the last 10 years indicates that the hormone acts rapidly (3-5 min) at the transcriptional level. Molecular, biochemical, genetic, and structural studies using early auxin inducible genes from Pisum sativum (pea) and Arabidopsis are proposed herein to gain insight into: (i) the molecular details of the signaling apparatus responsible for their transcriptional activation; and (ii) the role of their encoded polypeptides in plant growth and development. The specific aims of the proposal are: 1. To isolate the transcriptional factor(s) that interact with the auxin responsive domain A (AuxRD A) of the early PS-MA 4/5 gene using molecular genetic ("one-hybrid system" in yeast) or biochemical (DNA affinity chromatography) approaches. To clone and structurally characterize genomic sequences encoding this factor and determine its expression characteristics during plant development. 2. To isolate mutations in Arabidopsis that affect gene expression driven by AuxRD A using Arabidopsis lines already constructed expressing GUS via these domains. To done one of these mutations by positional cloning. 3. To biochemically characterize the PS-IAA4/5-like proteins and define the DNA sequences that bind at the putative beta-alpha-alpha DNA binding domain of these nuclear short-lived proteins. To isolate genomic sequences that contain the binding site (target/late genes). The elucidation of the primary mechanism of auxin action is of paramount importance in Plant Sciences. Understanding how auxin controls cell growth, meristem activity, xylogenesis, etc. will allow the engineering of plant species with improved properties and qualities.