A novel Dlg isoform and identification of its proteins

描述（由申请人提供）：黑腹果蝇是研究动物发育以及癌症形成的极好模式生物，因为所涉及的关键蛋白质在所有动物中都是保守的，并且苍蝇提供了巨大的实验优势。 大圆盘蛋白（Dlg）家族最初被鉴定为果蝇中的肿瘤抑制因子，随后鉴定出多种哺乳动物Dlg同源物。 现在已知它们在建立顶基细胞极性、形成细胞-细胞接触和在果蝇膜的细胞质表面上组装大蛋白复合物中起关键作用。 在哺乳动物中，Dlg同源物之一hDlg的截短导致颅面畸形和围产期死亡。 然而，Dlg的潜在机制在很大程度上仍然未知。 果蝇基因组测序的完成和许多新的dlg cDNA的回收最近揭示了以前未被注意到的多种Dlg亚型的存在。 主要研究人员发现，其中一种Dlg亚型Dlg-75可以执行以前分配给原型Dlg-A的许多Dlg功能。 为了了解Dlg-75的功能，她将使用两种方法寻找Dlg-75的相互作用蛋白。 首先，将进行一组强大的遗传筛选以选择调节Dlg-75活性或水平的基因。 第二，将用双杂交筛选鉴定能够与Dlg-75物理相互作用的蛋白质。 这两个屏幕都简单有效，执行时间相对较短。 考虑到Dlg-75相互作用蛋白斜视（Stbm）对于小鼠神经管形成是必需的，从这些筛选中鉴定Dlg-75相互作用蛋白将极大地促进对Dlg和Stbm在果蝇和人类的生长控制、细胞极性和发育中的机制的理解。

DESCRIPTION (provided by applicant): Drosophila melanogaster is an excellent model organism to study animal development as well as formation of cancer because the critical proteins involved are conserved in all animals, and flies offer tremendous experimental advantages. The Discs-Large (Dlg) family of proteins was originally identified as a tumor suppressor in flies, and multiple mammalian Dlg homologs were subsequently identified. They are now known to play critical roles in establishing apical-basal cell polarity, formation of cell-cell contacts, and assembly of large protein complexes on the cytoplasmic faces of membranes in flies. In mammals, truncation in one of Dlg homologs, hDlg, results in craniofacial dysmorphogenesis and perinatal death. However, the underlying mechanism of Dlg is still largely unknown. Completion of fly genome sequence and the recovery of many new dlg cDNAs recently revealed the presence of multiple Dlg isoforms that were previously unnoticed. The principal investigator discovered that one of those multiple Dlg isoforms, Dlg-75, may carry out many of Dlg functions previously assigned to the prototype Dlg-A. To understand the function of Dlg-75, she will search for the interacting proteins of Dlg-75 using two approaches. First, a set of powerful genetic screens will be carried out to select for the genes modulating the activity or level of Dlg-75. Second, proteins that are capable of physically interacting with Dlg-75 will be identified with two-hybrid screen. Both screens are simple and effective and take relatively short time to carry out. Considering that Strabismus (Stbm), a Dlg-75-interacting protein, is essential for neural tube formation of mice, identification of Dlg-75-interacting proteins from these screens will greatly facilitate understanding on the mechanism of Dlg and Stbm in growth control, cell polarity, and development in both flies and humans.