AUXIN-RESISTANT MUTANTS OF ARABIDOPSIS

拟议研究的长期目标是：1)了解 植物激素吲哚-3-乙酸(IAA)在植物生长和发育中的作用 利用拟南芥突变体的开发；2)鉴定和鉴定 生长素活动所需的蛋白质。这份提案描述了 涉及三个生长素抗性基因功能的实验 称为AxR1、AXR3和AXR4。AxR1基因已被克隆并编码一种 与泛素激活酶(EL)相似的新蛋白质。我们 打算继续我们对这个基因的分子分析，包括 基因结构和调控的特征。蜂窝位置 将通过细胞分离研究确定AxR1蛋白的 以及免疫荧光显微镜。AxR1的潜在作用 泛素途径中的蛋白质将在一系列体外实验中进行评估 使用纯化蛋白的研究。研究泛素化在人类免疫系统中的作用 植物激素的作用，我们将表征泛素-蛋白质结合物 在AxR1突变体中。AxR1基因异位表达的影响 对激素敏感性和植物发育的影响将被确定。至 鉴定与我们分离的AxR1蛋白相互作用的蛋白质 抑制AxR1突变体的一系列突变。这些突变 (称为生长素抗性抑制因子，sar)将被表征。我们 希望对这些相互作用的基因的分析将提供 关于AxR1基因和SAR功能的重要信息 精神错乱。 我们还建议研究另外两个生长素抗性基因，称为 AXR3和AXR4。Axr3和axr4突变体的表型表明 基因编码荷尔蒙活动所需的蛋白质。我们打算克隆 并描述了这两个基因座的特征。 我们预计，我们的研究将带来重大的新见解 植物激素的作用机制。此外，我们对 AxR1基因可能有助于理解肿瘤的调控机制。 都是真核生物。泛素途径参与了多种不同的 细胞过程，包括细胞周期控制、DNA复制、基因 表达、病毒感染和肿瘤发生。我们的研究表明 E1样蛋白的变化导致植物激素的减少 敏感度。因此，对这种蛋白质的进一步分析可能会导致 发现泛素的一种新的调节功能。

The long-term goals of the proposed research are: 1) to understand the role of the plant hormone indole-3-acetic acid (IAA) in plant growth and development using mutants of Arabidopsis; 2) to identify and characterize the proteins required for auxin action. This proposal describes experiments which address the function of three auxin-resistance genes called AXR1, AXR3,and AXR4. The AXR1 gene has been cloned and encodes a novel protein with similarity to ubiquitin-activating enzyme (El). We intend to continue our molecular analysis of this gene, including the characterization of gene structure and regulation. The cellular location of the Axr1 protein will be established by cell fractionation studies as well as immunofluorescence microscopy. The potential role of the Axr1 protein in the ubiquitin pathway will be assessed in a series of in vitro studies using purified protein. To examine the role of ubiquitination in plant hormone action, we will characterize ubiquitin-protein conjugates in the axr1 mutants. The effects of ectopic expression of the AXR1 gene on hormone sensitivity and plant development will be determined. To identify proteins which interact with the Axr1 protein we have isolated a series of mutations which suppress the axr1 mutants. These mutations (called suppressor of auxin resistance, sar) will be characterized. We expect that the analysis of these interacting genes will provided important information on the function of the AXR1 gene as well as the SAR loci. We also propose to study two additional auxin-resistance genes called AXR3 and AXR4. The phenotypes of axr3 and axr4 mutants suggest that both genes encode proteins required for hormone action. We intend to clone and characterize both of these loci. We anticipate that our studies will lead to significant new insight into the mechanism of plant hormone action. In addition, our analyses of the AXR1 gene may contribute to an understanding of regulatory mechanisms in all eukaryotes. The ubiquitin pathway has been implicated in diverse cellular processes, including cell cycle control, DNA replication, gene expression, viral infection and oncogenesis. Our studies indicate that changes in an E1-like protein result in a reduction in plant hormone sensitivity. Thus, further analysis of this protein may lead to the discovery of a new regulatory function for ubiquitin.