CAREER: Genetics of Pattern Formation in the Arabidopsis Shoot Apex

顶端分生组织(SAM)是植物所有地上组织的最终来源。SAM产生叶、茎、花和腋芽，并负责新梢的模式。尽管顶端分生组织在植物发育中起着至关重要的作用，但对这种结构的侧翼产生器官的机制几乎一无所知。利用一种新的突变系统，在SAM或周围细胞中的离散结构域中表现出GUS报告基因表达的增强子陷阱(ET)和基因陷阱(GT)转座系已经被鉴定出来。两个转座系显示了SAM特异的GUS表达。这些品系中控制GUS表达的基因可能在SAM识别和/或功能中起作用。已鉴定出8个转座系，它们在围绕SAM的离散的、新的结构域中显示GUS表达。这些表达模式似乎不反映解剖或形态特征，但基于基因表达定义新的结构域。在这些系中控制GUS表达的基因可能在器官起始过程中定义边界。这些品系是根据GUS表达模式确定的，控制这种表达的基因是未知的功能。为了开始了解这些基因在分生组织功能和器官发生中所起的作用，将进行一系列的分析。这些基因将被克隆和测序，并将对其表达模式进行详细的表征。为了确定在分生组织中起作用的基因之间的遗传关系，我们将在包含影响分生组织功能的突变的背景中，以及在异位表达选定分生组织基因的转基因植物中，研究我们的基因陷阱和增强子陷阱系中GUS的表达。这项建议的教育部分旨在培训本科生、研究生和博士后研究人员有关拟南芥研究的现代方法。拟南芥是植物生物学研究的模式生物。许多可用的拟南芥资源对所有植物生物学研究人员都是有用的。为了使植物生物学研究人员能够充分利用现有的拟南芥资源，熟悉拟南芥研究中使用的标准方法是很重要的。为此，将开发一门密集的实验室课程，教授标准的拟南芥方法。国际和平研究所研究计划的材料将用于实验室。此外，PI将作为研究生和博士后研究人员的导师，他们将实施本提案的研究部分。

The shoot apical meristem (SAM) is the ultimate source of all above groundtissues of the plant. The SAM gives rise to leaves, stems, flowers, andaxillary buds, and is responsible for the pattern of the shoot. Despitethe crucial role of the shoot apical meristem in plant development, almostnothing is known about the mechanisms by which organs are produced from theflanks of this structure. Using a novel mutagenesis system, enhancer trap(ET) and gene trap (GT) transposant lines that exhibit GUS reporter geneexpression in discrete domains in the SAM or surrounding cells have beenidentified. Two transposant lines show GUS expression specific to the SAM. The genes controlling GUS expression in these lines could play a role inSAM identity and/or function. Eight transposant lines have been identifiedthat show GUS expression in discrete, novel domains surrounding the SAM.These expression patterns do not appear to reflect anatomical ormorphological features, but define new domains based on gene expression.The genes controlling GUS expression in these lines may function to defineboundaries during organ initiation. These lines were identified based onGUS expression patterns, and the genes controlling that expression are ofunknown function. A series of analyses will be performed in order to beginto understand the role that these genes play in meristem function andorganogenesis. The genes will be cloned and sequenced, and a detailedcharacterization of their expression patterns will be performed. In orderto identify genetic relationships between genes that function in themeristem, GUS expression in our gene trap and enhancer trap lines will beexamined in backgrounds containing mutations that affect meristem function,and in transgenic plants that ectopically express selected meristem genes. The educational component of this proposal is geared towards trainingundergraduate and graduate students and postdoctoral researchers in modernmethods in Arabidopsis research. Arabidopsis thaliana is a model organismfor studies in plant biology. The many available Arabidopsis resources areof use to all plant biology researchers. In order for plant biologyresearchers to be able to take full advantage of the Arabidopsis resourcesthat are available, it is important that they be familiar with the standardmethods used in Arabidopsis research. To this end, an intensive laboratorycourse will be developed, that will teach standard Arabidopsis methods.Materials from the PI's research program will be used for the laboratories. In addition, the PI will serve as a mentor to graduate students andpostdoctoral researchers who will carry out the research component of thisproposal.