Wnt signaling pathway interactions in early anterior-posterior neuroectoderm patterning

项目摘要/摘要 胚胎形成早期神经外胚层的分子机制是沿着前胚层和外胚层。 后(AP)体轴和WNT信号网络控制多方面的机制 发育和成人动态平衡是基本的生物学问题。然而，还有很多事情要做。 发现了这些问题中的每一个，特别是在后口生物的早期发育过程中 Wnt信号对前后神经外胚层构型至关重要的胚胎。我们有 最近发现，3条不同但相互连接的WNT信令路径形成了WNT网络 在早期海胆胚胎中，沿着前后轴形成神经外胚层是必不可少的。 多种后口动物(棘皮动物，棘皮动物， 半角形动物、脊索动物)，包括脊椎动物，强烈地表明这个WNT网络的方面是 保守的。我们实验室研究的长期目标是系统地表征细胞外， 细胞内和转录因子参与控制早期AP神经外胚层的WNT网络 海胆身上的图案。R15的目标是建立转录基因调控 网络(GRN)在WNT网络下游激活，并执行初步功能研究以 揭示细胞外和细胞内的Wnt调节剂如何影响网络的活动。这个 中心假设是在细胞外的信号通路之间存在关键的相互作用， 细胞内和转录水平。其基本原理是，通过首先生成转录GRN 我们可以更好地了解细胞外和细胞内WNT网络如何集成到AP中 神经外胚层纹饰GRN。Aim1将发现由Wnt/JNK激活的转录因子，并 WNT/PKC信号通路在AP神经外胚层模式形成中的作用 筛选野生型胚胎与Wnt/JNK和Wnt/PKC基因敲除胚胎的比较。功能基因 将进行扰动研究，以建立转录GRN支架并定义关键字 转录水平上Wnt通路之间的相互作用。目标2将使用基因扰动 分析可能的胞外和胞内Wnt调节剂，以便更好地表征 在Wnt/JNK和Wnt/PKC转导通路中使用的通路成员，以识别可能的 这些调节器之间的相互作用，并了解这些调节器如何影响 在Aim1创建的新兴GRN。这项拟议的研究意义重大，因为它将是为数不多的 为确定这些WNT网络如何影响体内发育而进行的系统研究 模型系统。它还将为GRN在其他组织中的比较功能研究提供基线 后口模式物种，包括脊椎动物，从而填补了我们对 早期AP图案化机制的演变。

Project Summary/Abstract The molecular mechanisms by which embryos pattern the early neuroectoderm along the anterior- posterior (AP) body axis and the mechanisms by which Wnt signaling networks govern multiple aspects of development and adult homeostasis are fundamental biological questions. However, much remains to be discovered about each of these questions, especially during the early development of deuterostome embryos where Wnt signaling is essential for anterior-posterior neuroectoderm patterning. We have recently discovered that 3 different, but interconnected, Wnt signaling pathways form a Wnt network that is essential for patterning the neuroectoderm along the anterior-posterior axis in early sea urchin embryos. Comparison of functional and expression studies among multiple deuterostome species (i.e., echinoderms, hemichordates, chordates), including vertebrates, strongly suggests that aspects of this Wnt network are conserved. The long-term goal of the studies in our lab is to systematically characterize the extracellular, intracellular and transcriptional players involved in the Wnt network governing early AP neuroectoderm patterning in the sea urchin. The objective of this R15 is to establish the transcriptional gene regulatory network (GRN) activated downstream of the Wnt network and perform initial functional studies to uncover how extracellular and intracellular Wnt modulators influence the activity of the network. The central hypothesis is that there are key interactions among the signaling pathways at the extracellular, intracellular, and transcriptional level. The rationale is that by first generating the transcriptional GRNs we can better understand how the extracellular and intracellular Wnt network are integrated in the AP neuroectoderm patterning GRN. Aim1 will uncover the transcription factors activated by the Wnt/JNK and Wnt/PKC signaling pathways during AP neuroectoderm patterning using information from differential screens comparing wild type embryos with Wnt/JNK and Wnt/PKC knockdown embryos. Functional gene perturbation studies will be performed to establish the transcriptional GRN scaffold and to define key interactions between the Wnt pathways at the transcriptional level. Aim 2 will use gene perturbation analyses on putative extracellular and intracellular Wnt modulators in order to better characterize the pathway members used in the Wnt/JNK and Wnt/PKC transduction pathways, to identify possible interactions among these modulators between the pathways, and to learn how these modulators affect the emerging GRN created in Aim1. The proposed research is significant because it will be one of the few systematic studies conducted to determine how these Wnt networks influence development in an in vivo model system. It will also provide the baseline for comparative functional studies of the GRN in other deuterostome model species, including vertebrates, thereby filling in large gaps in our knowledge of the evolution of early AP patterning mechanisms.