DROSOPHILA SENSORY NEURON DEVELOPMENT

我们正在研究细胞粘附分子在果蝇神经系统发育过程中的作用。在上一个授权期间，我们已经克隆和鉴定了猎枪（shg）和微弱的香肠（as）。shg编码果蝇E-钙粘蛋白同源物，DE-钙粘蛋白; Fas编码Ig样蛋白超家族的一个新成员，我们将测试粘附功能作为本提案的一部分。粘附分子，特别是经典的钙粘蛋白，如E-钙粘蛋白，在所有动物中主要参与细胞分选，运动和分化的控制。E-钙粘蛋白是一种肿瘤抑制基因。到目前为止，对钙粘蛋白在神经发育过程中的功能知之甚少，大多数见解来自脊椎动物细胞培养系统的研究。我们的鉴定shg/DE-钙粘蛋白基因的突变，使我们有机会分析这个分子的功能，这是在神经外胚层和神经元亚群，在整个制剂的果蝇。建议产生一组shg/DE-钙粘蛋白的构建体，并使用它们在限定的发育阶段和限定的组织中过表达或去除该基因的功能。这些操作将使我们能够解决shg/DE-钙粘蛋白介导的粘附是如何参与神经元祖细胞的确定和迁移，轴突寻路和突触发生。我们将进一步使用我们的结构，在胚胎和果蝇52细胞，分析钙粘蛋白/连环蛋白复合物（CCC）在果蝇系统中的细胞粘附磷酸化的作用。我们的初步数据表明，膜结合酪氨酸激酶DER（EGF受体的果蝇同源物）磷酸化CCC，因为DER功能的丧失导致的表型与E-钙粘蛋白过表达导致的表型非常相似。我们将研究DER是否直接与CCC结合（如脊椎动物细胞系中所示），以及其激活是否导致shg/DE-钙粘蛋白和/或连环蛋白的磷酸化。我们相信，我们在果蝇中的shg/DE-钙粘蛋白的分析将进一步我们的经典钙粘蛋白的功能的一般理解。CCC可能是果蝇EGFR活性的直接靶点，这将拓宽我们对生长因子在胚胎发育中功能的理解。

We are studying the function of cell adhesion molecules during the development of the nervous system in Drosophila. During the previous granting period we have cloned and characterized shotgun (shg) and faint sausage ((as). shg encodes the Drosophila E-cadherin homolog, DE- cadherin; fas encodes a novel member of the superfamily of Ig-like proteins for which we will test an adhesive function as part of this proposal. Adhesion molecules, in particular classic cadherins such as E-cadherin, are centrally involved in the control of cell sorting, motility and differentiation in all animals. E-cadherin acts as a tumor suppressor gene. So far little is known about the function of cadherins during neural development; most insight has been gained from the study of vertebrate cell culture systems. Our identification of mutations in the shg/DE-cadherin gene gives us the opportunity to analyze the function of this molecule, which is expressed in the neuroectoderm and subpopulations of neurons, in whole preparations of Drosophila. It is proposed to generate a set of constructs of shg/DE-cadherin and use them to either overexpress or remove the function of this gene at defined developmental stages and in defined tissues. These manipulations will allow us to address how shg/DE-cadherin mediated adhesion is involved in the determination and migration of neuronal progenitors, axonal pathfinding, and synaptogenesis. We will further use our constructs, in both embryos and Drosophila 52 cells, to analyze the role of phosphorylation of the cadherin/catenin complex (CCC) in cell adhesion in the Drosophila system. Our preliminary data suggest that the membrane bound tyrosine kinase DER (Drosophila homolog of the EGF receptor) phosphorylates the CCC, since loss" of DER function causes a phenotype that closely resembles the phenotype resulting from E-cadherin overexpression. We will investigate whether DER directly binds to the CCC (as has been shown in vertebrate cell lines) and whether its activation leads to phosphorylation of shg/DE-cadherin and/or catenins. We believe that our analysis of shg/DE-cadherin in Drosophila will further our understanding of the function of classic cadherins in general. The possibility that the CCC is an immediate target of EGFR activity in Drosophila would widen our understanding of the function of growth factors in embryonic development.