EXPRESSION AND FUNCTIONS OF WNT GENES

Wnt基因家族成员与原癌基因Wnt-1相关 以及果蝇节段的无翼基因。WNT被认为是 BE分泌蛋白在脊椎动物胚胎发育中的作用 旁分泌或自分泌方式激活靶细胞上的受体。 而其功能意义、受体和机制 WNT-信号转导在很大程度上是未知的，人们认为WNT是 在胚胎的局部组织中瞬时表达，并发挥作用 模式在细胞间通讯中的重要作用 队形。支持这一点，放松对时间和空间的管制 神经特异性Wnt-1的表达导致非洲爪哇模式缺陷 胚胎，这些基因在小鼠体内的缺失导致中脑和 后脑缺陷。目前的项目将直接检验这一假设 Wnt基因家族在胚胎模式中起着至关重要的作用 在脊椎动物中形成并将研究信号传导 WNTS参与细胞间信号传递的途径。斑马鱼 (Brachydanio Rerio)将用于这些研究，因为它提供了基因 分析以及可获得的早期胚胎发育。具体的 目标如下：1.通过扩增Wnt基因家族 带有简并寡核苷酸引物的WNT序列，后面紧跟着cDNA 文库筛选以分离完整的编码序列。2.来自AIM的DNA 1将用于RNA印迹分析和原位杂交。 与此同时，抗血清将被开发并应用于 光镜和电子显微镜水平的免疫细胞化学。这些研究将 建立每个WNT表达的时间和空间模式。3. 将使用遗传方法来改变Wnt的表达，或进行干扰 具有WNT功能。对突变表型的分析可能会揭示 WNTS在发展中的作用。4.WNTT的路径 细胞之间的信号空间信息将通过检查 Wnt表达模式的放松是否会影响缝隙连接 通信和已知的第二信使系统，并通过追求 斑马鱼中在Wnt途径中工作的基因的同源物 果蝇。总的来说，这些研究将直接测试这些功能 和新发现的信号多肽的作用机制 当该基因异常表达时，可能与出生缺陷和 细胞的转化。

Members of the Wnt gene family are related to the proto-oncogene Wnt-1 and the Drosophila segment polarity gene wingless. Wnts are thought to be secreted proteins acting during vertebrate embryonic development in a paracrine or autocrine fashion to activate receptors on target cells. While the functional significance, receptors, and mechanisms of Wnt-signal transduction are largely unknown, it is thought that Wnts are transiently expressed in localized tissues of embryos, and that they play an important role in intercellular communication involved in pattern formation. Supporting this, deregulation of the timing and spatial expression of the neural-specific Wnt-1 causes pattern defects in Xenopus embryos, and deletion of these genes in mouse results in midbrain and hindbrain defects. The current project will directly test the hypothesis that the Wnt gene family plays an essential role in embryonic pattern formation in vertebrates and will investigate the signal transduction pathway involved in intercellular signalling by Wnts. The zebrafish (Brachydanio rerio) will be used for these studies, as it offers genetic analysis as well as accessible early embryonic development. The specific goals follow: 1. The Wnt gene family will be cloned by amplification of Wnt sequences with degenerate oligonucleotide primers, followed by cDNA library screening to isolate the full coding sequences. 2. cDNAs from Aim 1 will be employed for RNA blot analysis and for in situ hybridization while, in parallel, antisera will be developed and employed in immunocytochemistry at the light and EM level. These studies will establish the temporal and spatial pattern of expression of each Wnt. 3. Genetic approaches will be employed to alter Wnt expression, or interfere with Wnt function. Analysis of the mutant phenotypes may reveal insights into the roles of Wnts in development. 4. The pathways by which Wnts signal spatial information between cells will be studied by examining whether deregulation of Wnt patterns of expression affects gap junctional communication and known second messenger systems and by pursuing zebrafish homologues of genes which operate in the Wnt pathway in Drosophila. Collectively, these studies will directly test the functions and mechanisms of actions of newly discovered signalling polypeptides which may, when aberrantly expressed, be involved in birth defects and transformation of cells.