DISCS-LOST IN APICAL CELL JUNCTIONS IN DROSOPHILA EYE

描述（由申请方提供）：顶-基底细胞极性对上皮形态发生至关重要。视网膜分化涉及细胞间相互作用和连接组织的动态过程。果蝇复眼为研究这种细胞过程提供了一个很好的遗传模型。感光细胞分化的标志是顶端细胞膜中感光器官或横纹肌的爆炸性生长。果蝇Crumbs（Crb）蛋白在光感受器的横纹肌和粘附连接（AJ）的组织中起着关键作用。我们的目标是剖析Crb在感光细胞形态发生中的分子基础。 Crb是一种跨膜蛋白，具有一个短的胞质尾。该胞内结构域（Crb intra）可以募集MAGUK家族蛋白Stardust（Sdt）和PDZ结构域蛋白Discs-丢失（Dlt）以形成蛋白复合物。Crb复合物的一个重要功能是募集AJs并诱导和/或维持横纹肌的生长。另一种保守的蛋白质复合物由Bazooka，Par 6和非典型PKC（aPKC）组成，对上皮极性至关重要。有趣的是，Par 6共定位并直接与Dlt在顶膜相互作用。一种新的Dlt同源物Dlt样（Dlk）也直接结合Par 6。因此，它是建议，Dlt和Dlk可以调节的Crb和Par复合物之间的串扰。 为了验证这一假设，将通过遗传学、分子生物学和细胞化学方法分析Crb和Par复合物在感光细胞形态发生中的功能。将讨论Crb和Par功能是否需要Dlt和Dlk。具体的相互作用域的Dlt和Dlk和它们的功能在Par复杂的将被检查。此外，特定的蛋白质参与运输的细胞骨架的Crb和Par复合物将被确定，以了解AJ形成的机制。 果蝇和人类Crb蛋白在结构和功能上是保守的。人类CRB 1与视网膜疾病相关，包括视网膜色素变性12和Leber先天性黑蒙。因此，研究Crb和Par复合物的新型相互作用将为深入了解CRB 1在正常视网膜发育和CRB 1突变相关疾病中的作用机制提供重要的理论依据。

DESCRIPTION (provided by applicant): Apico-basal cell polarity is essential for epithelial morphogenesis. Retinal differentiation involves dynamic process of cell-cell interactions and junctional organizations. The Drosophila compound eye provides an excellent gentic model for studying such cellular processes. A hallmark of photoreceptor differentiation is an explosive growth of the photosensitive organ, or rhabdomere, in the apical cell membrane. Drosophila Crumbs (Crb) protein plays a key role in organizing the rhabdomere and adherens junction (AJ) of photoreceptors. Our goal is to dissect the molecular basis of Crb function in the photoreceptor morphogenesis. Crb is a transmembrane protein with a short cytoplasmic tail. This intracellular domain (Crb intra) can recruit a MAGUK family protein Stardust (Sdt) and a PDZ domain protein Discs-lost (Dlt) to form a protein complex. An important function of Crb complex is to recruit AJs and to induce and/or maintain growth of rhabdomeres. Another conserved protein complex composed of Bazooka, Par6 and atypical PKC (aPKC) is critical for epithelial polarity. Interestingly, Par6 colocalizes and directly interacts with Dlt at the apical membrane. A novel Dlt homolog, Dlt-like (Dlk), also directly binds Par6. Therefore, it is proposed that Dlt and Dlk may regulate the cross-talk between the Crb and Par complexes. To test this hypothesis, the function of Crb and Par complexes in photoreceptor morphogenesis will be analyzed by genetic, molecular and cytochemical methods. Whether Dlt and Dlk are required for Crb and Par functions will be addressed. Specific interaction domains of Dlt and Dlk and their functions in the Par complex will be examined. In addition, specific proteins involved in trafficking of cytoskeletons to the Crb and Par complexes will be identified to understand the mechanism of AJ formation. Drosophila and human Crb proteins are conserved in structure and function. Human CRB1 is associated with retinal diseases including retinitis pigmentosa 12 and Leber Congenital Amaurosis. Therefore, studies on novel interaction of Crb and Par complexes will provide important insights into the mechanism of human CRB 1 in normal retinal development and diseases associated with CRB1 mutations.