Identification of new Wnt signaling components

描述(由申请人提供)： 细胞接收和解释来自细胞外环境的信号 通过被称为信号转导通路的生化级联反应。这些 这些通路控制着细胞生长和分化的许多方面。突变 激活这些过程通常在人类癌症中发现。一个重要的 这方面的例子可以在Wnt信号通路中找到。WNT是被隐藏起来的 无脊椎动物和脊椎动物发育过程中常用的糖蛋白 这是通过高度保守的信号装置发挥作用的。隐性的 该通路的负调控因子突变和功能增益突变 积极的效应者在几种癌症中起着因果作用。我们的目标是 通过研究Wingless(Wg)井识别新的WNT信号组件 果蝇Wnt的特征。 在一种方法中，进行了基因筛查，以确定一个基因， GAM，在过度表达时阻断Wg信号。删除 GAM活性也会导致Wg信号的丢失。GAM编码一种蛋白质，带有一个 推测的核定位序列和一个PHD手指。分子 GAM在Wg信号转导中的作用机制将从遗传学角度进行探讨 苍蝇和果蝇细胞培养中的上位症，可能结合的鉴定 GAM蛋白的合作伙伴和系统结构/功能突变 分析。两个预测的具有显著序列相似性的人类基因 在数据库中也发现了GAM。这些基因将被克隆 并进行分析，以确定它们是否在WNT信号转导中发挥重要作用 人类细胞系。 第二种方法利用了最近的一项发现：孵化 果蝇细胞具有与特定基因相对应的dsRNA特定靶点 该基因的信使核糖核酸降解。这项技术将用于筛选 最近在脊椎动物中涉及的几个因子的潜在苍蝇同源物 通过蛋白质-蛋白质相互作用筛选的WNT信号。如果减少了一个 基因的表达导致Wg信号在细胞培养中发挥作用，然后飞行 缺乏这些基因的突变体将被分离并分析Wg信号 缺陷。获得对这些假设的重要性的遗传确认 WNT信令组件将为他们的研究提供信心 癌症生物学的背景和作为药物发现的目标。

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.