DISCS-LOST IN APICAL CELL JUNCTIONS IN DROSOPHILA EYE

描述（来自申请人摘要的逐字记录）：果蝇复眼 由胚盘上皮发育而来。椎间盘的分化 原基进入成年人的眼睛涉及动态的细胞-细胞相互作用， 连续的细胞命运决定。我们的长期目标是了解 视网膜分化过程中顶端细胞-细胞接触的分子基础。 Dlt是一种新的PDZ结构域蛋白，定位于细胞的顶端， 膜。DLT是建立胚胎顶基极性的关键 上皮细胞DLT也是胚胎干细胞增殖和/或存活所必需的。 椎间盘细胞在发展的眼睛，Dlt似乎是至关重要的规格 色素细胞的命运和视网膜底的形成，以支持感光细胞 视网膜上皮内的簇。 Dlt蛋白含有四个参与蛋白质-蛋白质相互作用的PDZ结构域。 这表明Dlt可能在眼睛发育过程中发挥多种作用， 与特定的蛋白质伴侣相互作用。为了研究PDZ结构域的作用 DLT和相互作用蛋白质，四个具体的目标。第一、 含有一系列截短的Dlt构建体的转基因果蝇将被 生成的.将在体内测试突变体构建体以确定是否 椎间盘生长和/或顶膜需要特异性PDZ结构域 Dlt的本地化其次，由于Dlt的丢失似乎会导致 初级色素细胞，将进行克隆分析，以确定 细胞类型需要表达Dlt以正确地指定初级色素 细胞第三，Dlt和Delta之间的相互作用将在 生化遗传和免疫细胞化学水平来证实我们的初步研究 Dlt与Delta（一种膜结合配体， 缺口。第四，Dlt与Crumbs的胞内结构域（Crbintra）相互作用。 Crbintra的过表达和Dlt的缺失导致了细胞内类似的缺陷。 眼，这表明Crbintra作为显性负因子Dlt。的 由Crbintra引起的眼表型将被用作有效的遗传系统， 发现影响眼睛中Dlt和Crb功能的新突变。 已经发现了与Dlt相似的脊椎动物蛋白质序列。 Dlt和Notch信号蛋白将提供有用的见解功能 脊椎动物同源物在细胞与细胞相互作用和信号传导中的作用。

DESCRIPTION (Verbatim from applicant's abstract): The Drosophila compound eye develops from the imaginal disc epithelium. Differentiation of a disc primordium into an adult eye involves dynamic cell-cell interactions and successive cell fate decisions. Our long-term objective is to understand the molecular basis of apical cell-cell contacts during retinal differentiation. Discs-lost (Dlt), a novel PDZ domain protein, is localized at the apical membranes. Dlt is essential for establishing apico-basal polarity of embryonic epithelia. Dlt is also required for proliferation and/or survival of imaginal disc cells. In the developing eye, Dlt appears to be crucial for specification of pigment cell fates and formation of retinal floor to support photoreceptor clusters within the retinal epithelium. Dlt protein contains four PDZ domains involved in protein-protein interactions. This suggests that Dlt may play multiple roles during eye development by interacting with specific protein partners. To study the role or PDZ domains of Dlt and interacting proteins, four specific aims are proposed. First, transgenic flies containing a series of truncated Dlt constructs will be generated. Mutant constructs will be tested in vivo to determine whether specific PDZ domains are required for disc growth and/or apical membrane localization of Dlt. Second, since loss of Dlt appears to cause misrouting of primary pigment cells, clonal analysis will be performed to determine which cell types need to express Dlt for correct specification of primary pigment cells. Third, interaction between Dlt and Delta will be examined at biochemical, genetic and immunocytochemical levels to confirm our preliminary evidence that Dlt interacts genetically with Delta, a membrane-bound ligand for Notch. Fourth, Dlt interacts with intracellular domain of Crumbs (Crbintra). Overexpression of Crbintra and loss of Dlt results in similar defects in the eye, suggesting that Crbintra acts as a dominant-negative factor for Dlt. The eye phenotype caused by Crbintra will be used as an efficient genetic system to find new mutations affecting Dlt and Crb function in the eye. Vertebrate protein sequences similar to Dlt have been found. These studies on Dlt and Notch signaling proteins will provide useful insights into the function of vertebrate homologs in cell-cell interaction and signaling.