CONTROL OF DEVELOPMENT IN DICTYOSTELIUM BY CAMP

分泌环核苷酸磷酸二酯酶及其抑制剂 糖蛋白，其控制细胞外cAMP水平， 盘基网柄藻的发育。 这两种分子都是 在这个实验室里净化。 我们已经克隆了它们的基因并分析了 每一个的结构和规则。 环核苷酸 磷酸二酯酶（PDE）基因是最复杂的，但其特征在于， 生物体和介导的趋化和基因调控事件在所有阶段 的发展周期。 抑制基因只在 发展的聚合阶段。 我们会继续研究由 PDE和抑制剂。 一个尚未解决的问题是， PDE附着于质膜的外表面 在发展的聚集阶段。 我们将测试一个模型， 预示着一种不寻常的依恋 一旦了解了这个机制 我们将研究修改附件的生物学后果。 第三个启动子的发现，这是活跃的，只有在晚期 发展，只有在前柄细胞导致的作用分析 cAMP和腺苷在聚集后细胞类型比例中的作用 发展 每个启动子将与β-半乳糖苷酶融合， 确定其在所有发展阶段的活动场所。 然后我们将 使用融合到各种启动子的PDE、抑制剂和其他基因， 转化细胞并调节细胞外cAMP的浓度， 腺苷在聚集后形态发生期间。 PDE的聚集特异性和柄细胞特异性启动子 基因和抑制基因的启动子将被分析， 将研究改变它们的生物效应。

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.