Collaborative Research: Specification of Excitatory Fates in the Spinal Cord

该项目研究了当胚胎发育和生长时，如何形成功能正常的神经回路。这项工作的重点是斑马鱼胚胎的脊髓回路，它在生命早期发育，比大脑中的神经回路更简单，更易于实验处理。目标是确定关键的调节基因，这些基因指导细胞生长成一种特定的神经细胞群（中间神经元），具有控制精确身体运动的特定功能。该项目的结果将具有广泛的适用性，因为这些类型的神经细胞存在于所有脊椎动物（包括人类）中。在这项研究中发现的基因以及它们影响神经细胞和神经回路发育的方式在许多不同的物种中可能是相似的。这个项目将大大增加对基因如何指导细胞以特定特征发育的理解，以及特定基因在神经元回路构建中所起的作用。主要研究人员将把这项研究纳入他们的大学教学和对公众的演讲中。这项研究将通过妇女和代表性不足的少数民族的积极参与，促进科学工作人员的多样化。主要研究人员还将在当地的城市高中开展外展活动，并为9年级/10年级和高阶高中生物学生开发教学模块。这些活动的目的是显著影响传统上服务不足的高中学生的生活，并激发少数民族高中学生对科学和研究的热情。理解神经元网络如何生成的关键第一步是确定不同的中间神经元（INs）如何被指定具有特定的功能属性。帮助定义INs的一个关键特性是它们使用哪种神经递质与其他细胞交流。神经递质可以是兴奋性的或抑制性的，使用不适当的神经递质会形成故障电路。因此，确定如何指定IN神经递质特性对于理解IN和回路发育至关重要。相对而言，我们对脊髓兴奋性神经网络特性的定义知之甚少。该提案将描述一个基因调控网络（GRN），指定脊髓IN兴奋特性，使用斑马鱼作为模型系统。研究人员已经确定了编码11种不同dna结合蛋白的基因，作为指定V0v IN兴奋性（谷氨酸能）特性的GRN的候选成员。v0vins位于脊髓中部，在运动回路中起着至关重要的作用。研究小组已经证明，其中四个基因evx1/2和lmx1ba/b是v0vins正确兴奋状态所必需的。此外，在evx1/2双突变体中，V0v INs失去了lmx1ba/b和其他7个基因的表达，这表明这9个基因都可能在evx1/2的下游作用，决定V0v的谷氨酸能特性。本提案的具体目标是测试这7个其他基因中的任何一个是否需要正确的V0v神经递质特性，并确定所有这些evx1 /2调节基因之间的上位关系。单一和复合斑马鱼突变体将被用来回答这些问题。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project examines how appropriately-functioning neuronal circuits are made as embryos develop and grow. The work focuses on circuits in the spinal cord of zebrafish embryos, which develop early in life and are simpler and more experimentally-tractable than neural circuits in the brain. The goal is to identify key regulatory genes that instruct cells to grow into one particular population of nerve cells (interneurons) with specific functions in controlling precise body movements. The outcomes of this project will be widely applicable, because these types of nerve cell exist in all vertebrates (including humans). The genes identified in this study and the ways that they influence nerve cell and circuit development are likely to be similar in many different species. This project will significantly increase understanding of how genes instruct cells to develop with particular characteristics, and the roles that specific genes play in the construction of neuronal circuitry. The principal investigators will incorporate this research into their university teaching and presentations made to the general public. This research will contribute to the diversification of the scientific workforce through the active participation of both women and under-represented minorities. The principal investigators will also perform outreach to local city high schools and develop teaching modules for both 9th/10th grade and advanced placement high school Biology students. The aim of these activities is to significantly impact the lives of traditionally under-served high school students and enthuse under represented minority high school students about science and research.An essential first step in understanding how neuronal networks are generated is determining how distinct interneurons (INs) are specified with particular functional properties. One key property that helps to define INs is which neurotransmitter they use to communicate with other cells. Neurotransmitters can be excitatory or inhibitory and INs utilizing inappropriate neurotransmitters form malfunctioning circuits. Therefore, determining how IN neurotransmitter properties are specified is crucial for understanding both IN and circuit development. Relatively little is known about how excitatory spinal IN properties are specified. This proposal will characterize a gene regulatory network (GRN) that specifies spinal IN excitatory properties, using zebrafish as a model system. The investigators have identified genes that encode for 11 different DNA-binding proteins as candidate members of a GRN that specifies V0v IN excitatory (glutamatergic) properties. V0v INs reside in the middle of the spinal cord and have crucial roles in locomotor circuitry. The research team has already shown that four of these genes, evx1/2 and lmx1ba/b are required for correct excitatory fates of V0v INs. In addition, in evx1/2 double mutants V0v INs lose expression of both lmx1ba/b and the other 7 genes, suggesting that all 9 of these genes may act downstream of Evx1/2 in specifying V0v glutamatergic properties. The specific objectives of this proposal are to test if any of these 7 other genes are required for correct V0v neurotransmitter properties and determine the epistatic relationships among all of these Evx1/2-regulated genes. Single and compound zebrafish mutants will be used to answer these questions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.