The Role of 5'Nucleotidase-expressing Cells in the Regulation of Morphogenesis in Dictyostellium

自20世纪30年代以来，发育生物学家一直在研究轴向梯度和极性建立的机制。虽然早期的研究提供了关于形态发生的描述性信息，但他们也强调了分子方法的必要性。目前，人们对确定这些分子事件的技术和方法重新燃起了热情。就目前的研究而言，几年前的研究表明，盘基骨柱在细胞分化的时间过程中出现了一种磷酸酶活性（5'NT），并且这种活性仅限于形成两种分化细胞类型之间界面的狭窄细胞带。活性对5′amp具有特异性，活性域从质膜外表面延伸。该项目有两个主要目标：(1)通过破坏5nt基因的表达、过表达和异位表达来确定该基因在调控形态发生中的作用。由此产生的对形态发生的影响将通过分析细胞类型特异性标记和基因来确定，这些标记和基因指示了两种主要细胞类型的分化进程，并且(2)确定导致细胞特异性表达5'NT基因的调节机制。这将需要鉴定调节时间和空间表达的顺式作用因子，以及鉴定和克隆调节基因表达的反式作用因子。

Since the 1930's, developmental biologists have studied the mechanisms of axial gradients and the establishment of polarity. Although the early investigations offered descriptive information about morphogenesis they also emphasized the need for molecular approaches. There is currently renewed enthusiasm that the techniques and approaches are now available to define these molecular events. With regard to the present research, it was shown several years ago that a phosphatase activity (5'NT ) appeared during the time course of cell differentiation in Dictyostelium and that the activity becomes restricted to a narrow band of cells that form the interface between the two differentiating cell types. The activity was specific for 5'AMP and the activity domain extended from the external face of the plasma membrane. There are two major goals of the project: (1) to identify the role played by this gene in the regulation of morphogenesis by disruption of expression of the 5'NT gene, overexpression and ectopic expression. The resulting effects on morphogenesis will be determined through the analysis of cell-type specific markers and genes that are indicative of the progression of differentiation in the two major cell types, and (2) to identify the regulatory mechanisms that result in cell-specific expression of the 5'NT gene. This will require identification of cis-acting factors that regulate the temporal and spatial expression, and identification and cloning of trans-acting factors that regulate expression of the gene.