Specification of Stochastic Left-Right Asymmetric Neuronal Fates in C. elegans

描述（由申请人提供）：人类神经系统由数千种具有不同基因表达和功能模式的细胞类型组成。使神经元亚型多样化的一种一般方法是通过以下方式来指定单个细胞类型的不同身份和功能： 随机神经元命运选择然而，在神经系统中产生随机细胞多样性的机制只被部分理解。梭elegans左右AWC嗅觉神经元通过随机的、协调的细胞信号事件指定不对称的亚型，这使得动物能够区分不同的气味。我们已经确定，这种随机细胞命运的选择是通过一个短暂的，胚胎NSY-5/innexin间隙连接神经网络，拮抗下游的Ca 2+调节途径，建立持久的不对称AWC身份。该提议的总体目标是使用该系统作为模型来鉴定间隙连接介导的瞬时信号传导事件协调长期随机神经元命运选择的分子机制。在这项资助计划中，我们将检验细胞间Ca 2+信号转导介导nsy-5神经网络中AWC和非AWC之间的通讯以协调随机AWC亚型选择（目的1）的假设，研究Ca 2+激活的SLO K+通道和新发现的MOK的作用。（K+通道修饰剂）分子在AWC亚型选择中的作用（Aim 2），并确定调节TIR-1/Sarm 1 Ca 2+信号支架蛋白突触定位的机制，以进行AWC亚型选择（目的3）。通过短暂的间隙连接依赖性细胞网络建立持久的神经元亚型提供了一种创新、强大且简单的系统，以阐明体内发育中间隙连接介导的细胞间信号传导的生物学功能的分子机制，这在脊椎动物中并不容易实现。由于我们研究的基因的人类同源物中的突变与各种发育障碍相关，因此了解这些基因的正常功能的机制细节将为新的治疗策略提供信息。

DESCRIPTION (provided by applicant): The human nervous system consists of thousands of cell types with distinct patterns of gene expression and functions. One general way to diversify neuronal subtypes is to specify different identities and functions of individual cell types through stochastic neuronal fate choices. However, the mechanisms that generate stochastic cellular diversity in the nervous system are only partly understood. The C. elegans left and right AWC olfactory neurons specify asymmetric subtypes through a stochastic, coordinated cell signaling event, which allows the animal to discriminate between different odors. We have identified that this stochastic cell fate choice is regulated through a transient, embryonic NSY-5/innexin gap junction neural network that antagonizes a downstream Ca2+-regulated pathway to establish long-lasting asymmetric AWC identities. The overall goal of this proposal is to use this system as a model to identify the molecular mechanisms by which gap junction-mediated transient signaling events coordinate long- term stochastic neuronal fate choice. In this grant proposal, we will test the hypothesis that intercellular Ca2+ signaling mediates communication between AWCs and non-AWCs in the nsy-5 neural network to coordinate stochastic AWC subtype choice (Aim 1), investigate the role of Ca2+-activated SLO K+ channels and newly identified MOK (modifier of K+ channel) molecules in AWC subtype choice (Aim 2), and identify the mechanisms that regulate the synaptic localization of the TIR-1/Sarm1 Ca2+ signaling scaffold protein for AWC subtype choice (Aim 3). The establishment of long-lasting neuronal subtypes by a transient gap junction-dependent cell network provides an innovative, robust, and simple system to elucidate the molecular mechanisms underlying the biological function of gap junction-mediated intercellular signaling in development in vivo, which is not readily feasible in vertebrates. As mutations in the human homologs of the genes we study are associated with a variety of developmental disorders, understanding normal functions of these genes in mechanistic detail will inform novel therapeutic strategies.