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.
