EXPRESSION AND FUNCTIONS OF WNT GENES

Wnt基因家族的成员与原癌基因Wnt-1相关 和果蝇体节极性基因wingless。 Wnt被认为 是在脊椎动物胚胎发育过程中起作用的分泌蛋白， 以旁分泌或自分泌方式激活靶细胞上的受体。 虽然功能意义，受体，和机制， Wnt信号转导在很大程度上是未知的，认为Wnt是 在胚胎的局部组织中短暂表达， 在细胞间通讯中起重要作用， 阵 支持这一点，放松对时间和空间的管制 神经特异性Wnt-1的表达导致非洲爪蟾的模式缺陷 胚胎，并删除这些基因在小鼠中的结果， 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重要作用， 在脊椎动物中形成，并将研究信号转导 参与Wnts细胞间信号传导的途径。斑马鱼 （Brachydanio rerio）将用于这些研究，因为它提供了遗传学上的优势。 分析以及可获得的早期胚胎发育。 具体 目标如下：1. Wnt基因家族将通过扩增 Wnt序列与简并寡核苷酸引物，随后是cDNA 文库筛选以分离全部编码序列。2.来自Aim的cDNA 1将用于RNA印迹分析和原位杂交 与此同时，将开发抗血清并用于 免疫细胞化学光、电镜观察。 这些研究将 建立每个Wnt表达的时间和空间模式。3. 将采用遗传方法来改变Wnt表达或干扰Wnt表达。 Wnt功能。 对突变表型的分析可能会揭示 Wnt在发育中的作用4. Wnts通过的途径 将通过检查来研究细胞之间信号空间信息 Wnt表达模式的失调是否影响缝隙连接 通信和已知的第二信使系统， 斑马鱼的同源基因在Wnt途径中起作用， 果蝇 总的来说，这些研究将直接测试功能 和新发现的信号多肽的作用机制 当异常表达时，可能与出生缺陷有关， 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.