Role of an LRR Receptor-Like Kinase in Root Epidermal Patterning

在发育过程中，所有多细胞生物都会产生不同的细胞类型，并将这些细胞类型以适当的模式组织起来。该项目的研究旨在揭示生物在发育过程中产生和形成不同细胞类型的基因和分子机制。本项目使用一个简单的模型系统来研究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模式产生。此外，根表皮随着根的生长而不断形成，因此可以一次检查所有发育阶段。最后，缺乏任何一种根表皮细胞类型的植物都是可存活的，这使得复杂的分子遗传操作得以进行。最近的研究表明，拟南芥根表皮的细胞类型规范依赖于一个复杂的转录调控网络。几种转录因子在表皮发育过程中产生，这些转录因子参与正负反馈回路，根据它们的位置维持或抑制它们在特定细胞中的表达。这个项目的研究旨在解决这个系统中的一个重要问题：是什么导致一个位置的细胞以不同于另一个位置的细胞的方式表达这些基因？最近，一种名为scramble （SCM）的受体样蛋白被发现影响细胞类型的位置依赖模式。本项目旨在研究这种受体样SCM蛋白的具体作用。主要目的是：(1)确定SCM mRNA和蛋白在发育根中的位置；(2)分析SCM受体功能与转录调控网络之间的关系；(3)表征与SCM蛋白相似的其他受体样蛋白；(4)鉴定SCM信号通路的新遗传成分。这些研究路线有望为发育过程中位置线索作用的分子基础提供见解。更一般地说，这将有助于更好地理解多细胞生物中产生和调节细胞多样性的机制。

0316312Schiefelbein During their development, all multicellular organisms generate diverse cell types and organize these cell types in appropriate patterns. The research in this project is designed to uncover the genes and the molecular mechanisms used by living things to produce and to pattern distinct cell types during development. This project uses a simple model system to study cell-type 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 pattern. Furthermore, the root epidermis is formed continuously as the root grows, so all stages of development can be examined at a single time. Finally, plants that lack either root epidermal cell type are viable, which enables sophisticated molecular genetic manipulations to be conducted. Recent studies suggest that cell type specification in the Arabidopsis root epidermis relies on a complex transcriptional regulatory network. Several transcription factors are produced during epidermis development, and these are involved in positive and negative feedback loops that maintain or inhibit their expression in particular cells, depending on their position. The research in this project is intended to address an important question in this system: What causes cells in one position to express these genes in a different way than cells in another position? Recently, a receptor-like protein, SCRAMBLED (SCM), has been identified that influences the position-dependent pattern of cell types. This project is designed to examine the specific role of this receptor-like SCM protein. The major aims are: (1) to define the location of the SCM mRNA and protein in the developing root, (2) to analyze the relationship between the SCM receptor function and the transcriptional regulatory network, (3) to characterize other receptor-like proteins that are similar to the SCM protein, and (4) to identify new genetic components of the SCM signaling pathway. These lines of investigation are expected to provide insights into the molecular basis for the action of positional cues during development. More generally, this will lead to a better understanding of the mechanisms employed to generate and regulate cellular diversity in multicellular organisms.