Identification of new Wnt signaling components

描述（由申请人提供）： 细胞接收并解释来自细胞外环境的信号 通过被称为信号转导途径的生化级联反应。这些 途径控制细胞生长和分化的许多方面。突变 在人类癌症中经常发现激活这些过程。一个重要 这方面的例子是在Wnt信号通路中发现的。Wnt是分泌的 无脊椎动物和脊椎动物发育过程中常用的糖蛋白 通过一个高度保守的信号装置发挥作用。隐性 通路负调节因子突变和功能获得性突变 在一些癌症中，正效应子起着因果作用。我们的目标是 通过研究Wingless（Wg）， 描述了果蝇Wnt. 在一种方法中，进行遗传筛选，其鉴定基因， gammy legs（gam），其在过度表达时阻断Wg信号传导。去除 gam活动还导致Wg信号传导的丧失。gam编码一种蛋白质， 推定的核定位序列和PHD指。分子 Gam在Wg信号传导中的作用机制将使用遗传学方法来研究。 果蝇和果蝇细胞培养物中的上位性，鉴定可能的结合 Gam蛋白的伴侣和系统性结构/功能突变 分析.两个具有显著序列相似性的预测人类基因 也在数据库中被识别。这些基因将被克隆 并进行分析以确定它们是否在Wnt信号传导中起重要作用。 人类细胞系。 第二种方法利用了最近的发现， 果蝇细胞与dsRNA对应的特定基因指定的目标 该基因的mRNA降解。这项技术将用于筛选 最近涉及脊椎动物的几种因子的潜在蝇同源物 通过蛋白质-蛋白质相互作用筛选Wnt信号传导。如果减少a 基因的表达导致Wg信号传导在细胞培养中受到影响， 将分离缺乏这些基因的突变体并分析Wg信号传导 缺陷获得这些假定的重要性的遗传确认 Wnt信号传导组件将提供信心，继续他们的研究， 癌症生物学的背景和药物发现的目标。

DESCRIPTION (provided by applicant): Cells receive and interpret signals from their extracellular environment through biochemical cascades known as signal transduction pathways. These pathways control many aspects of cell growth and differentiation. Mutations activating these processes are often found in human cancers. An important example of this is found in the Wnt signaling pathway. Wnts are secreted glycoproteins commonly used during invertebrate and vertebrate development that function through a highly conserved signaling apparatus. Recessive mutations in negative regulators of the pathway and gain-of-function mutations in positive effecters play a causal role in several cancers. Our goal is to identify new Wnt signaling components, by studying Wingless (Wg), a well characterized Drosophila Wnt. In one approach, a genetic screen was performed which identified a gene, gammy legs (gam), which blocks Wg signaling when over expressed. Removal of gam activity also leads to loss of Wg signaling. gam encodes a protein with a putative nuclear localization sequence and a PHD finger. The molecular mechanism of Gam action in Wg signaling will be persued using genetic epistasis in flies and fly cell culture, identification of possible binding partners for the Gam protein and a systematic structure/function mutational analysis. Two predicted human genes that have signficant sequence similarity to gam have also been identified in the database. These genes will be cloned and analyzed to determine if they play an important role in Wnt signaling in human cell lines. The second approach takes advantage of the recent finding that incubating Drosophila cells with dsRNA corresponding to a particular gene specify targets that gene's mRNA for degradation. This technology will be used to screen potential fly homologs of several factors recently implicated in vertebrate Wnt signaling through protein-protein interaction screens. If reduction of a gene's expression causes Wg signaling to be effected in cell culture, then fly mutants lacking these genes will be isolated and analyzed for Wg signaling defects. Obtaining genetic confirmation of the importance of these putative Wnt signaling components will provide the confidence to pursue their study in the context of cancer biology and as targets for drug discovery.