Elucidating the mechanisms of gradient dependent and independent Wnt signaling in neuronal development

阐明神经元发育中梯度依赖和独立的 Wnt 信号传导机制

• 批准号: RGPIN-2021-03154
• 负责人: Mizumoto, Kota
• 金额: $ 2.62万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=766134
• 关键词: Elucidating; mechanisms; gradient; dependent; independent

Background The Wnt family of morphogens play crucial roles in animal development. Wnt proteins are known to generate gradient distributions within a tissue. However, it is not well understood how cells sense and interpret the Wnt gradients and to what extent the gradient distribution of Wnt contributes to animal development. Several studies, including our recent work, suggest that the gradient distribution of Wnts is dispensable in some aspects of animal development. This project is designed to increase our understanding of the gradient dependent and independent mechanisms of Wnt signaling using roundworm, Caenorhabditis elegans, as a model system. Progress Recently, we reported that Wnt instructs retraction of the neuronal processes or neurites, called neurite pruning. Time-lapse imaging of the developing PDB (posterior dorsal B) neuron in C. elegans revealed that some neurites undergo stereotyped pruning. We found the PDB neurite pruning depends on the Wnt signal. Strikingly, we did not observe pruning defects in the `non-diffusible Wnt' mutants. This observation suggests the gradient distribution of Wnt is not necessary for PDB neurite pruning. Interestingly, we found the position of PDB synapses depends on the Wnt gradient. Taken together, our results showed that a single neuron uses gradient dependent and independent Wnt signaling in a context-dependent manner. Research Objectives and Methods The long-term objective of this program is to understand the diverse actions of Wnt signaling in animal development. Our short-term objective is to expand our knowledge in gradient dependent and independent Wnt signaling in neuronal development using C. elegans. We will address the following specific research objectives.  1. Uncovering the mechanism of gradient independent Wnt signaling in neurite pruning. Using genetic screenings, we will uncover the downstream effectors of Wnt signaling in neurite pruning.  2. Uncovering the mechanisms of gradient dependent Wnt signaling in synapse positioning. Using genetic screenings, we will uncover Wnt effector genes that specifically function in controlling synapse positioning.  3. Understanding which neurodevelopmental events are Wnt gradient dependent. We will examine the various neurodevelopmental events known to be regulated by Wnt signaling using `non-diffusible wnt' mutants we generate. Impact We will reveal the mechanisms of Wnt-dependent neurite pruning and synapse positioning, both of which are still poorly understood. We will also characterize which neurodevelopmental processes depend on the Wnt gradient. Knowledge gained from our research will help better understand the complex actions of Wnt signaling in animal development. It will also help other researchers to test if the same mechanisms are present in other model organisms. We will raise internationally competitive next-generation scientists with broad expertise in genetics, molecular biology, and microscopy through our research program.

背景 形态发生素的 Wnt 家族在动物发育中发挥着至关重要的作用，但目前尚不清楚细胞如何感知和解释 Wnt 梯度以及 Wnt 梯度分布的贡献程度。包括我们最近的工作在内的多项研究表明，Wnt 的梯度分布在动物发育的某些方面是可有可无的，该项目旨在加深我们对蛔虫的 Wnt 信号传导的梯度依赖和独立机制的理解。秀丽隐杆线虫，作为模型系统 进展 最近，我们报道了 Wnt 指示神经元突起或神经突的收缩，称为神经突修剪。对秀丽隐杆线虫中发育中的 PDB（后背 B）神经元进行延时成像，结果显示一些神经突。我们发现 PDB 神经突修剪依赖于 Wnt 信号，令人惊讶的是，我们没有观察到修剪缺陷。 “非扩散性 Wnt”突变体表明 Wnt 的梯度分布对于 PDB 神经突修剪来说不是必需的。该计划旨在研究 Wnt 信号在动物发育中的多种作用。为了利用线虫扩展我们对神经元发育中梯度依赖性和独立性 Wnt 信号传导的认识，我们将实现以下具体研究目标： 1. 揭示神经突修剪中梯度依赖性 Wnt 信号传导的机制。神经突修剪中 Wnt 信号传导的下游效应子 2. 揭示突触定位中梯度依赖性 Wnt 信号传导的机制，我们将发现具有特定功能的 Wnt 效应子基因。 3. 了解哪些神经发育事件是 Wnt 梯度依赖性的 我们将使用我们生成的“非扩散性 Wnt”突变体来检查已知受 Wnt 信号调节的各种神经发育事件。依赖的神经突修剪和突触定位，这两者仍然知之甚少，我们还将描述哪些神经发育过程依赖于 Wnt 梯度，从我们的研究中获得的知识将有助于更好地理解这个复杂的过程。它还将帮助其他研究人员测试其他模型生物中是否存在 Wnt 信号传导的作用，我们将通过我们的研究培养在遗传学、分子生物学和显微镜学方面具有广泛专业知识的国际下一代科学家。程序。