AUXIN SIGNALING APPARATUS

以吲哚-3-乙酸(IAA)为代表的植物激素生长素调节 植物生长发育的各个方面，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、趋向性，通常被认为是 负责调节植物细胞的生长。尽管重要的是 生长素植物发育--生长素的主要分子机制 行动未知。 过去10年积累的实验证据表明， 激素在转录水平上起作用迅速(3-5分钟)。分子， 利用早期生长素诱导物进行生化、遗传和结构研究 豌豆和拟南芥的基因在这里被提出以获得 深入了解：(I)信号装置的分子细节 负责它们的转录激活；以及(Ii) 它们编码的多肽在植物生长发育中的作用。具体的 这项建议的目的是： 1.分离与生长素相互作用的转录因子(S) 早期PS-MA 4/5基因反应域A(AuxRD A)的分子生物学研究 遗传(酵母中的“单杂交系统”)或生化(DNA亲和力 层析)接近。克隆基因组并分析其结构特征 编码该因子的序列并确定其表达 植物发育过程中的特征。 2.分离影响基因表达驱动的拟南芥突变 通过AuxRD A利用已构建的表达GUS的拟南芥品系 这些域。通过位置克隆来完成这些突变之一。 3.对PS-IAA4/5样蛋白进行生化鉴定，并确定 与假定的β-α-αDNA结合的DNA序列 这些核短寿命蛋白的结构域。分离基因组序列 包含结合位点(靶基因/晚基因)的基因。 阐明生长素的主要作用机制至关重要。 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、木质化等将允许工程 具有改进的特性和质量的植物物种。

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.