Wnt signaling pathway interactions in early anterior-posterior neuroectoderm patterning

项目概要/摘要 胚胎沿前部形成早期神经外胚层的分子机制 后 (AP) 身体轴以及 Wnt 信号网络控制多个方面的机制 发育和成人体内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，特别是在后口动物的早期发展过程中 Wnt 信号对于前后神经外胚层模式至关重要。我们有 最近发现 3 个不同但相互关联的 Wnt 信号通路形成一个 Wnt 网络 对于早期海胆胚胎中沿前后轴形成神经外胚层的模式至关重要。 多个后口动物物种（即棘皮动物、 半索动物、脊索动物），包括脊椎动物，强烈表明该 Wnt 网络的各个方面 保守的。我们实验室研究的长期目标是系统地表征细胞外、 参与控制早期 AP 神经外胚层的 Wnt 网络的细胞内和转录参与者 海胆上的图案。该 R15 的目标是建立转录基因调控 网络（GRN）激活 Wnt 网络下游并进行初步功能研究 揭示细胞外和细胞内 Wnt 调节剂如何影响网络的活动。的 中心假设是细胞外信号通路之间存在关键的相互作用， 细胞内和转录水平。基本原理是首先生成转录 GRN 我们可以更好地理解细胞外和细胞内Wnt网络是如何集成在AP中的 神经外胚层模式 GRN。 Aim1 将揭示 Wnt/JNK 激活的转录因子和 使用差异信息分析 AP 神经外胚层模式化过程中的 Wnt/PKC 信号通路 将野生型胚胎与 Wnt/JNK 和 Wnt/PKC 敲低胚胎进行比较的筛选。功能基因 将进行扰动研究以建立转录 GRN 支架并定义关键 Wnt 通路之间在转录水平上的相互作用。目标 2 将使用基因扰动 对假定的细胞外和细胞内 Wnt 调节剂进行分析，以便更好地表征 Wnt/JNK 和 Wnt/PKC 转导途径中使用的途径成员，以确定可能的 这些调节剂之间的相互作用，并了解这些调节剂如何影响 在 Aim1 中创建的新兴 GRN。拟议的研究意义重大，因为它将是为数不多的研究之一 进行系统研究以确定这些 Wnt 网络如何影响体内发育 模型系统。它还将为 GRN 在其他领域的比较功能研究提供基线 后口动物模型物种，包括脊椎动物，从而填补了我们对后口动物知识的巨大空白 早期 AP 模式机制的演变。

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.