Molecular Basis of Sensory Transduction in C elegans

描述（由申请人提供）：拟议工作的长期目标是了解机械转导的机制。探测机械能的能力对于我们的触觉、听觉、平衡以及姿势、渗透平衡和血压的持续调节至关重要。近年来，对线虫、果蝇、斑马鱼和老鼠的经典和前沿遗传方法已经产生了一个小的、但不断扩大的触觉和听觉所需蛋白质清单。然而，目前尚不清楚是否所有这些蛋白质都在感觉机械转导中起作用，或者如果有的话，它们如何协同作用将机械能转化为神经元中的电信号。我们拟研究秀丽隐杆线虫触觉敏感神经元的分子生理学。由于几个原因，秀丽隐杆线虫几乎是这项研究的理想动物。现在，大量收集的触觉不敏感突变体、强大的分子遗传工具、对神经系统解剖的无与伦比的描述，与记录来自单个已识别的机械感觉神经元的电信号的能力共存。新发现的相似之处秀丽隐杆线虫的生理学脊椎动物触摸敏感神经元显著增加秀丽隐杆线虫作为一个模型系统的价值。在本研究中，我们重点研究了两类机械感觉神经元（非纤毛PLM神经元和纤毛ASH神经元）。将对正常动物的PLM和ASH进行电生理记录，以确定这些不同类型的机械感觉细胞的机械转导如何不同（目的#1A， 3A）。我们将通过比较野生型和突变型细胞的感觉反应来确定预测形成感觉转导通道和电压门控K通道的蛋白质的细胞功能（AIMS 1A， 3B和3C）。为了研究细胞结构如何促进力传递，我们还将记录细胞外和细胞内结构缺陷的突变动物（Aim 1B）。最后，我们将在异源细胞中表达PLM功能所需的通道，并确定已知的辅助蛋白如何调节单通道活性（目的2）。从这些研究中了解到的信息将阐明机械转导的基本机制，并可以改善与遗传和获得性疾病相关的感觉神经病变的诊断和治疗。

DESCRIPTION (provided by applicant): The long-term objective of the proposed work is to understand mechanisms of mechanotransduction. The ability to detect mechanical energy is essential for our senses of touch, hearing, and balance as well as for on-going regulation of posture, osmotic balance, and blood pressure. In recent years, classical and forward genetic approaches in nematodes, fruit flies, zebra fish, and mice have yielded a small, but expanding list of proteins needed for touch and hearing. However, it is not clear whether or not all of these proteins function in sensory mechanotransduction or, if so, how they might act in concert to convert mechanical energy into electrical signals in neurons. We propose to investigate the molecular physiology of touch-sensitive neurons in the nematode Caenorhabditis elegans. For several reasons, C. elegans is a nearly ideal animal for this research. Now, extensive collections of touch-insensitive mutants, powerful molecular-genetic tools, and an unparalleled description of nervous system anatomy, co-exist with the ability to record electrical signals from single, identified mechanosensory neurons. Newly discovered parallels in the physiology of C. elegans vertebrate touch-sensitive neurons significantly increase the value of C. elegans as a model system. In this proposal, we focus on two classes of mechanosensory neurons (nonciliated PLM neurons and ciliated ASH neurons). Electrophysiological recordings will be made from PLM and ASH in normal animals to determine how mechanotransduction differs in these distinct classes of mechanosensory cells (Aims #1A, 3A). We will determine the cellular function of proteins predicted to form sensory transduction channels and voltage-gated K channels by comparing sensory responses in wild type and mutant cells (AIMS 1A, 3B, & 3C). To investigate how cellular architecture contributes to force transfer, we will also record from mutant animals with defects in extracellular and intracellular structures (Aim 1B). Finally, we will express channels needed for PLM function in heterologous cells and determine how known accessory proteins regulate single channel activity (Aim 2). What is learned from these studies will clarify basic mechanisms of mechanotransduction and could improve the diagnosis and treatment of sensory neuropathies associated with both inherited and acquired diseases.