Molecular Genetics of Auxin Action in Arabidopsis

植物生长素是植物生长的许多方面所必需的 发展 生长素似乎刺激细胞伸长和细胞生长， 在完整的植物中分裂。 生长素被认为是植物生长所必需的 因为它是植物细胞生长所必需的 在文化中。 尽管它的重要性，很少有人知道， 生长素的作用机制 这项研究旨在更好地确定 生长素如何调节细胞活动的分子细节， 为了了解生长素对发育的调节， 整个工厂。 这项研究的重点是拟南芥，因为它是 特别适合于分子遗传学和经典遗传学 问题研究 参与生长素作用的基因将从 对所施用的生长素没有正常反应的突变体。 之一 以这种方式分离的突变体称为生长素抗性1或AXR1。 某些axr1突变体植物已经在PI中表征， 实验室和突变体显示出一些缺陷，这表明 缺陷的生长素反应。 AXR1基因将被克隆， 核苷酸序列测定。 遗传学研究表明， 基因位于一号染色体上，非常接近以前分离的 DNA片段。 该DNA片段将用于分离AXR1 使用一种叫做染色体步移的技术。 一旦克隆， 基因将被导入axr1突变体植物中， 为拟南芥开发的转化程序。 生长素损失 转化植物中的抗性将证实AXR1基因 被正确克隆了。 AXR1基因的DNA序列将是 确定并用于推导该基因的氨基酸序列 产品，并将与其他以前的序列进行比较 孤立的基因 分离的基因也将允许确定 植物中的哪些细胞产生AXR1基因产物。 的 AXR1基因的分子特征应该导致重要的 对生长素在植物发育中作用的新认识。

The plant hormone auxin is required for many aspects of plant development. Auxin appears to stimulate cell elongation and cell division in intact plants. Auxin is thought to be essential for plant cell growth because it is absolutely required for growth of plant cells in culture. Despite its importance, very little is known about the mechanism of auxin action. This research proposes to better determine the molecular details of how auxin regulates cellular events as a basis for understanding auxin regulation of development at the level of the whole plant. The focus of this research is Arabidopsis thaliana because it is particularly well suited to both molecular and classical genetic studies. Genes involved in auxin action will be identified from mutants which do not respond normally to applied auxin. One of the mutants isolated in this way is called auxin resistant 1 or axr1. Certain axr1 mutant plants have been characterized in the PI's laboratory and the mutants display a number of defects which suggest defective auxin responses. The AXR1 gene will be cloned and the nucleotide sequence determined. Genetic studies have shown that the gene lies on chromosome one, very close to a previously isolated fragment of DNA. This fragment of DNA will be used to isolate the AXR1 gene using a technique called chromosome walking. Once cloned, the gene will be introduced into axr1 mutant plants using plant transformation procedures developed for Arabidopsis. Loss of auxin resistance in the transformed plants will confirm that the AXR1 gene has been correctly cloned. The DNA sequence of the AXR1 gene will be determined and used to deduce the amino acid sequence of the gene product and will be compared with the sequences of other previously isolated genes. The isolated gene will also allow determination of which cells in the plant are making the AXR1 gene product. The molecular characterization of the AXR1 gene should lead to important new insights into the role of auxin in plant development.