Molecular Genetics of Cell Fate Specification in the Arabidopsis Root Epidermis

Schiefelbein 9724149 多细胞生物体具有不同的细胞类型，这些细胞类型以适当的模式组织以产生功能组织和器官。发育生物学领域的一个重大谜团是定义各种细胞类型的命运和模式的机制的本质。植物是研究这种发育问题的有用生物，因为它们的许多组织由简单的细胞类型阵列组成，并且它们的细胞谱系可以很容易地追踪。 在本项目中，根表皮的形成在开花植物拟南芥被用作一个模型，了解细胞的命运和模式在发展过程中的分子机制。在拟南芥根表皮细胞类型的形成是一个非常简单和优雅的细胞位置依赖的命运规范的例子，这个实验系统是服从分子，遗传和细胞分析。主要优点之一是根表皮仅由两种细胞类型组成，根毛细胞和无毛细胞，并且它们的命运由表皮细胞与其下层皮层细胞邻居的位置关系决定。 在最近的研究中，已经确定了三个基因（命名为TTG，WER和GL2），在根表皮发育的早期阶段，需要适当的细胞类型规格。本研究旨在：（1）明确GL 2基因在根表皮发育过程中的调控，（2）分析WER基因与TTG和GL 2基因的关系，并确定其在根表皮细胞命运中的作用，（3）利用GL 2启动子融合构建体作为细胞类型特异性标记基因，研究根表皮的发育特征。这些研究的结果预计将提供一个更好的了解特定的基因控制表皮细胞的命运在拟南芥以及新的见解的一般机制采用多细胞生物体控制细胞类型的多样性和图案。

Schiefelbein 9724149 Multicellular organisms possess diverse cell types that are organized in appropriate patterns to generate functional tissues and organs. One of the great mysteries in the field of developmental biology is the nature of the mechanism that defines the fates and patterns of the various cell types. Plants are useful organisms with which to study this developmental problem because many of their tissues are composed of a simple array of cell types and their cell lineages can be traced easily. In the present project, root epidermis formation in the flowering plant Arabidopsis thaliana is used as a model for understanding the molecular mechanisms underlying cell fate and patterning during development. The formation of cell types in the Arabidopsis root epidermis is a remarkably simple and elegant example of cell position-dependent fate specification, and this experimental system is amenable to molecular, genetic, and cellular analyses. One of the major advantages is that the root epidermis is composed of only two cell types, root-hair cells and hairless cells, and their fates are determined by the positional relationship of the epidermal cells to their underlying cortical cell neighbors. In recent studies, three genes (named TTG, WER, and GL2) have been identified that are required for proper cell type specification at an early stage in root epidermis development. The research in the present project period is designed to: (1) define the regulation of the GL2 gene during root epidermis development, (2) analyze the relationship of the WER gene to the TTG and GL2 genes and determine its role in root epidermis cell fate, and (3) study the developmental features of the root epidermis by using a GL2 promoter fusion construct as a cell-type specific marker gene. The results of these studies are expected to provide a greater understanding of the specific genes controlling epidermis cell fate in Arabidopsis as well as novel insights into the general mechanisms employed by multicellular organisms to control cell-type diversity and patterning.