Molecular Genetics of Cell Differentiation in Arabidopsis

该研究的目的是了解从选择细胞的发育命运到阐述其最终分化表型的步骤。 这个问题正在研究使用的头发（毛状体）的植物拟南芥叶片作为一个模型，了解控制细胞分化。 这些毛状体是从表皮延伸出来的高度特化的单细胞。 虽然在田间，拟南芥的毛状体已被证明提供了显着的保护免受昆虫食草动物，毛状体是在实验室条件下的非必需的。 此外，毛状体位于植物的表面上，并且容易观察到突变体表型。 毛状体的这两个特征有利于突变体的分离和遗传分析。 已经鉴定了影响毛状体发育和/或形态的二十多个不同基因中的突变，并且已经克隆了影响毛状体发育的三个基因。 毛状体发育途径中最早起作用的两个基因被证明是转录因子。 这些基因使表皮细胞进行高度特化的分化过程，包括细胞形状的巨大变化。 目前，人们对转录因子如何控制生物体中细胞的极化生长等过程知之甚少。 本项目的最终目标是将细胞命运决定过程中发生的事件与负责成熟毛状体细胞表型的细胞机制联系起来。 这种联系在所有生物中都知之甚少，对毛状体发育的研究可能会产生对理解植物和动物发育具有广泛意义的结果。

The objective of the research is to understand the steps that lead from the selection of a cell's developmental fate to the elaboration of its ultimate differentiated phenotype. This problem is being studied using hairs (trichomes) on the leaves of the plant Arabidopsis thaliana as a model for understanding the control of cell differentiation. These trichomes are highly specialized single cells that extend out from the epidermis. Although in the field, Arabidopsis trichomes have been shown to provide significant protection from insect herbivores, trichomes are non-essential under laboratory conditions. In addition, trichomes are located on the surface of the plant, and mutant phenotypes are readily observed. These two features of trichomes have facilitated the isolation of mutants and genetic analysis. Mutations in more than twenty different genes have been identified that affect trichome development and/or morphology, and three genes affecting trichome development have been cloned. Two of the earliest-acting genes in the trichome development pathway have turned out to be transcription factors. These genes commit an epidermal cell to a highly specialized differentiation process involving dramatic changes in cell shape. At present, there is little understanding of how transcription factors can control processes such as polarized growth of a cell in any organism. The ultimate goal of this project is to connect events occuring during the cell fate decision and the cellular mechanisms responsible for the mature trichome cell phenotype. This connection is poorly understood in all organisms, and the study of trichome development is likely to produce results with broad implications for understanding development in plants and animals.