Molecular Genetics of Cell Patterning in the Arabidopsis Root Epidermis

[0779 . 000]所有多细胞生物在其发展过程中都必须解决一个基本问题：如何从一个单一的原始细胞中产生不同类型的细胞？在这个项目中进行的研究旨在解决这个问题，并帮助揭示生物以适当的模式产生不同细胞类型的分子机制。本项目采用一个简单的模型系统来研究细胞命运规范；开花植物拟南芥根表皮的形成。拟南芥的根表皮是特殊的，因为它的两种细胞类型以可预测的位置依赖的方式产生。此外，根表皮是随着根的生长而不断形成的，因此在发育的各个阶段都可以很容易地跟踪表皮细胞的形成。最后，缺乏任何一种根表皮细胞类型的植物都是可以存活的，这使得复杂的基因实验成为可能。在最近的研究中，发现了四个编码转录调节因子的基因（称为TTG， WER， GL2和CPC）控制着两种表皮细胞类型的模式。细胞类型的正常模式似乎是由于这些调节因子在根发育过程中适当的产生、分布和相互作用。本课题的研究旨在：(1)更清晰地定义WER调控因子与其他各因子之间的相互作用；(2)阐明WER与影响茎表皮细胞命运的密切相关的转录调控因子之间的功能关系；(3)揭示表皮细胞模式的新调控因子。这些研究的结果有望为更多地了解拟南芥和一般多细胞生物在发育过程中产生和调节细胞多样性所使用的分子和机制提供帮助

0779000SchiefelbeinAll multicellular organisms must solve a fundamental problem during their development: How to generate different cell types from a single original cell? The research conducted in this project is designed to address this question and help uncover the molecular mechanisms used by living things to produce distinct cell types in appropriate patterns.This project employs a simple model system for studying cell fate specification; the formation of the root epidermis in the flowering plant Arabidopsis thaliana. The Arabidopsis root epidermis is exceptional because its two cell types are produced in a predictable position-dependent fashion. Furthermore, the root epidermis is formed continuously as the root grows, so the formation of the epidermal cells can be easily followed at all stages of development. Finally, plants that lack either root epidermal cell type are viable, enabling sophisticated genetic experimentation.In recent studies, four genes encoding putative transcriptional regulators (named TTG, WER, GL2, and CPC) have been found to control the patterning of the two epidermal cell types. It appears that the normal patterning of the cell types is due the appropriate production, distribution, and interaction of these regulators during root development. The research in the present project period is intended to: (1) more clearly define the interactions between the WER regulator and each of the other factors, (2) illuminate the functional relationship between the WER and a closely-related transcriptional regulator affecting shoot epidermis cell fate, and (3) uncover new regulators of epidermal cell patterning. The results of these studies are expected to provide a greater understanding of the molecules and mechanisms employed by Arabidopsis and multicellular organisms in general, to generate and regulate cellular diversity during development