Molecular, Cellular, and Physiological studies of Multidrug-Resistance-like ABC Transporters in Arabidopsis Seedlings

模式植物拟南芥具有22个耐多药（MDR）样基因。对这些基因的研究是合理的，因为在NSF之前的支持下获得的证据表明，MDR基因通过控制植物生长激素生长素的流动和分布，在控制植物生长和发育方面发挥了重要作用，而且这些发现可能会揭示与人类健康有关的基本细胞过程。（癌细胞中动物MDR1基因的过度表达与耐药肿瘤的发展有关。）下一个资助周期的活动重点是研究MDR基因（特别是MDR1和MDR4）如何控制PIN生长素外排调节因子的亚细胞定位，从而控制生长素的分布。这项工作将使我们更详细地了解生长素依赖事件在细胞和分子水平上如何影响植物的形态和形状。实验将包括1)使用电子成像和定制计算软件定量mdr突变表型，2)使用荧光标记的mdr和PIN蛋白研究蛋白质定位和运输动力学，3)MDR1和MDR4细胞质尾部的结构-功能研究以了解靶向机制。除了确定MDR蛋白的功能以及生长素如何控制植物生长和发育的科学目标外，该项目还将包括促进公众对植物的更多了解以及激发年轻人思考植物生物学科学的活动。在这个项目中资助的人员开发了一个旅行发现植物！可以在学校的科学展览会上设立外展展览。通过多种媒介（活体植物，显微镜，电脑视频和家庭作业），幼儿园到八年级的学生接触到基本植物生物学的各个方面及其与我们日常生活的相关性。发现植物!将进一步发展及扩阔，吸纳更多研究生操作员。在更高的科学水平上，还将通过一个网站进行推广，该网站将解释和演示如何通过一系列图像测量形状，特别是植物形状。将提供可下载的软件和一些示例图像。工程、数学和计算网站之间的链接将增加这些学科之间的信息和思想交流。这样的论坛将吸引工程和计算学科的科学家对植物生物学问题的关注，预计将产生广泛的影响。

The model plant Arabidopsis thaliana possesses 22 Multidrug Resistance (MDR)-like genes. Study of these genes is justified by the evidence, obtained with previous NSF support, that the MDR genes play an important role in the control of plant growth and development by controlling the flow and distribution of the plant growth hormone auxin, as well as by the possibility that the findings will shed light on basic cellular processes related to human health. (Over-expression of the animal MDR1 gene in cancer cells is linked to the development of drug-resistant tumors.) The activities proposed for the next funding cycle are focused on learning how the MDR genes (particularly MDR1 and MDR4) control the subcellular localization of the PIN auxin efflux regulators, which in turn control distribution of auxin. The work will result in a more detailed understanding of how auxin-dependent events at the cellular and molecular levels influence the form and shape of plants. The experiments will include 1) quantification of mdr mutant phenotypes using electronic imaging and custom computational software, 2) studies of protein localization and kinetics of trafficking using fluorescently-tagged MDR and PIN proteins, 3) structure-function studies of the cytoplasmic tail of MDR1 and MDR4 to learn about the targeting mechanism.In addition to the scientific goals of determining the functions of MDR proteins and how auxin controls plant growth and development, the project will include activities to promote a greater understanding of plants in the public at large and to stimulate youth to think about the science of plant biology. The personnel funded in this project have developed a traveling Discover Plants! outreach exhibit that can be set up at school science fairs. Through a mixture of media (live plants, microscopes, computer videos, and take-home projects), kindergarden through 8th grade students are exposed to various aspects of basic plant biology and its relevance to our everyday lives. Discover Plants! will be further developed and broadened to include more graduate student operators. Outreach at a higher scientific level will also occur via a website that will explain and demonstrate how measurements of shapes, plant shapes in particular, are made from a series of images. Downloadable software and some sample images will be provided. Links to and from engineering, mathematics, and computational sites will increase the exchange of information and ideas between these disciplines. Such a forum is expected to have a broad impact by attracting the attention of scientists in engineering and computational disciplines to issues in plant biology.