GENETIC CONTROL OF LEAF EXPANSION IN ARABIDOPSIS

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。这个项目的目的是通过研究激素生长素(吲哚乙酸)指导模式植物拟南芥叶片展开的分子/遗传机制来增加对发育的理解。生长素通过泛素-26S蛋白小体途径触发转录因子的选择性降解。然而，激素的接收如何导致转录因子的加速降解和发育生理的改变尚不清楚，尽管该实验室的早期工作表明，生长素在转录因子蛋白分解之前与第二种非生长素生长效应物质相互作用，控制叶片的展开。我们将使用突变分析来解决这里提出的特定目标，其中包括：(1)确定与假想的生长效应的产生相关的基因(S)和(2)确定与生长素控制植物叶片扩展有关的其他信号转导角色的基因。了解植物泛素化的调节可能有助于深入了解同源人类系统的功能。几种人类癌症是由泛素途径故障引起的。生长素也被怀疑是内分泌干扰物。这一子项目的结果也可能有助于理解这些化合物如何在干扰哺乳动物发育方面发挥作用。自2005年1月1日这一分项目开始以来，购买并安装了一个大型伸缩式生长室(AC-60“大脚怪”；加拿大温尼伯Enconair)，这对于建立统一的生长和筛选突变植物的条件至关重要。已经开始了一系列初步的生长实验，以优化生长条件。用不同浓度的甲烷磺酸乙酯对大量野生型拟南芥种子(CS1092；Lehle Seed，ROUND ROCK，TX)进行诱变处理。突变的种子(M1)已经被培养成种子(M2)。预计M2的细胞将包含纯合突变，这些突变将被筛选出感兴趣的表型。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project is intended to increase understanding of development though examination of the molecular/genetic mechanism by which the hormone auxin (indole acetic acid) directs leaf expansion in the model plant Arabidopsis thaliana. Auxin is known to trigger selective degradation of transcription factors via the ubiqutin-26S proteosome pathway. It is not known, however, how hormone reception leads to accelerated transcription factor degradation and altered developmental physiology although earlier work in this laboratory suggests auxin interacts, in advance of transcription factor proteolysis, with a second non-auxin growth effecter in controlling leaf expansion. We will use mutational analysis to address the specific aims proposed here which include (1) identifing the gene(s) associated with production of the hypothesized growth effector and (2) identifying genes responsible for other signal transduction players in auxin control of leaf expansion in plants. Understanding of the regulation of ubiquitination in plants may provide insights into the function of the orthologous human system. Several human cancers result from ubiquitin pathway malfunction. Auxins are also suspected endocrine disrupters. The results of this subproject may also lead to an understanding of how these compounds function in disturbing mammalian development. Since the start date of this sub-project, January 1, 2005, a large reach-in growth chamber (AC-60 "Bigfoot"; Enconair, Winnipeg, Canada), essential for establishing uniform conditions underwhich to grow and screen mutated plants, has been purchased and installed. A series of preliminary growth experiments have been initiated to optimize growth conditions. A large number of wild type Arabidopsis seeds (CS 1092; Lehle Seeds, Round Rock, TX) have been mutagenized with ethyl methane sulfonate at a range of concentrations. Mutated seed (M1) has been grown for seed (M2). The cells of the M2 are expected to contain homozygous mutations which will be screened for phenotypes of interest.