CONTROL OF DEVELOPMENT IN DICTYOSTELIUM BY CAMP

分泌环核苷酸磷酸二酯酶及其抑制物 控制胞外cAMP水平的糖蛋白 盘基网眼菌的发育。这两个分子都 在这个实验室提纯的。我们现在已经克隆了它们的基因并分析了 每一项的结构和规则。环核苷酸 磷酸二酯酶(Pde)基因是迄今发现的最复杂的基因。 并在所有阶段调节趋化和基因调节事件 在发育周期中。抑制物基因仅在 开发的聚合阶段。 我们会继续研究由 PDE和抑制剂。一个悬而未决的问题是 该PDE连接到质膜的外表面 在开发的聚合阶段。我们将测试一个模型， 预示着一种不同寻常的依恋形式。一旦了解了这种机制 我们将研究修改附件的生物学后果。 发现第三个启动子只在晚些时候活跃 并对其在前柄细胞发育中的作用进行了分析 CAMP和腺苷在聚集后细胞类型比例中的作用 发展。每个启动子都将与β-半乳糖苷酶融合，以 确定其在发展的所有阶段的活动地点。到时候我们会的 利用PDE、抑制物和其他基因融合到各种启动子上 转化细胞，调节细胞外cAMP和cAMP浓度 聚集后形态发生过程中的腺苷。 PDE的聚集特异性启动子和茎细胞特异性启动子 将对抑制基因的启动子和基因进行分析，并对 改变它们的生物学效应将被研究。

The cyclic nucleotide phosphodiesterase and its inhibitor are secreted glycoproteins that control extracellular levels of cAMP during the development of Dictyostelium discoideum. Both of these molecules were purified in this laboratory. We have now cloned their genes and analysed the structure and the regulation of each. The cyclic nucleotide phosphodiesterase (PDE) gene is the most complex yet characterized in this organism and mediates chemotactic and gene regulation events at all stages of the developmental cycle. The inhibitor gene is expressed only during the aggregation phase of development. We will continue our studies of the regulatory system constituted by the PDE and the inhibitor. A question that is unsolved is the mechanism by which the PDE is attached to the external face of the plasma membrane during the aggregation phase of development. We will test a model that predicts an unusual form of attachment. Once the mechanism is understood we will study the biological consequences of modifying the attachment. The discovery of a third promoter that is active only during late development and only in prestalk cells has led to the analysis of the role of cAMP and adenosine in cell type proportioning during post-aggregation development. Each promoter will be fused to beta-galactosidase to determine its site of activity at all stages of development. We will then use the PDE, the inhibitor and other genes fused to various promoters to transform cells and regulate the concentrations of extracellular cAMP and adenosine during post-aggregation morphogenesis. The aggregation specific and the stalk cell specific promoters of the PDE gene and the promoter of the inhibitor gene will be analysed and the biological effects of altering them will be studied.