Identification of genes that regulate electrical synapse formation in vivo

描述(申请人提供)：该项目的长期目标是了解调节体内神经回路和电突触形成的分子通路。神经回路是由突触组成的，突触是连接和交流的特殊场所，其模式和特性构成了所有大脑功能的基础。突触可以是化学的，信号通过神经递质的释放和接收传递，也可以是电子的，信号直接通过神经元之间的缝隙连接传递。其中，化学突触近年来受到了更多的关注，然而越来越多的证据表明，电子突触在大脑中广泛存在，它们在那里调节从视觉到记忆和学习的神经处理。潜在的神经回路和突触形成是确保神经元选择合适的目标并将复杂的突触机制招募到接触部位的遗传机制。然而，调控这些过程的基因还不是很清楚，特别是关于电突触的形成。我们建议建立斑马鱼Mauthner(M)回路作为理解神经元目标选择和电突触形成的遗传基础的模型。特征明确的M回路简单易懂，是典型的逃逸反应行为所必需的。这些特性，加上专门标记神经回路细胞及其定型的化学和电子突触的遗传工具，提供了一个独特的机会来发现影响电突触发生的突变，了解这些缺陷的细胞基础，并评估它们的行为后果。其目标是证明影响M电突触形成的突变可以使用正向遗传筛选(Aim1)来识别，以证明这些突变在细胞生物水平(AIM2)特异性地影响电突触形成，并且它们具有在M介导的逃逸反应(Aim3)水平上明显的功能缺陷。总体而言，这项提议将评估M回路是否是研究脊椎动物中枢神经系统电突触形成的合适平台；这将为揭开潜在的细胞和分子机制奠定基础。考虑到突触发育或功能缺陷与许多神经发育障碍有关，包括自闭症和癫痫，以及与年龄相关的疾病，如阿尔茨海默氏症和S，这些知识是至关重要的。对突触如何构建的基本了解，对于改进神经疾病的检测和指导治疗的发展至关重要。

DESCRIPTION (provided by applicant): The long-term goal of this project is to understand the molecular pathways that regulate neural circuit and electrical synapse formation in vivo. Neural circuits are organized by synapses, which are specialized sites of adhesion and communication whose patterns and properties form the basis of all of brain function. Synapses can be either chemical, where signals are transmitted via neurotransmitter release and reception, or electrical, where signals pass directly through gap junctions between neurons. Of these, the chemical synapse has received more attention in recent years, however growing evidence suggests that electrical synapses are widespread in the brain where they modulate neural processing from vision to memory and learning. Underlying neural circuit and synapse formation are genetic mechanisms ensuring that neurons select appropriate targets and recruit the complex synaptic machinery to the sites of contact. However, the genes that regulate these processes are not well understood, especially in regard to electrical synapse formation. We propose to establish the zebrafish Mauthner (M) circuit as a model for understanding the genetic basis of neuronal target selection and electrical synapse formation. The well-characterized M circuit is simple and accessible, and is necessary for a stereotypical escape response behavior. These properties, in conjunction with genetic tools that specifically mark the cells of the neural circuit and their stereotyped chemical and electrical synapses, provide a unique opportunity to find mutations that affect electrical synaptogenesis, to understand the cellular basis of these defects, and to assess their behavioral consequences. The goal is to demonstrate that mutations affecting M electrical synapse formation can be identified using a forward genetic screen (Aim1), to demonstrate that these mutations specifically affect electrical synapse formation at the cell- biological level (Aim2) and that they have functional deficits that are evident at the level of the M-mediated escape response (Aim3). Overall this proposal will evaluate whether the M circuit is a suitable platform for studying vertebrate CNS electrical synapse formation; this will lay the groundwork for unraveling the underlying cellular and molecular mechanisms. Such knowledge is critical given that defects in synapse development or function are associated with a number of neurodevelopmental disorders, including autism and epilepsy, and also age-related diseases, such as Alzheimer<s. A fundamental understanding of how synapses are built is essential for improved detection of neurological disease and for guiding the development of therapies.