NEURAL CONTROL OF A MOTOR PROGRAM

拟议研究的目标是了解细胞、遗传、 以及神经系统控制的分子机制 线虫的排便行为。 主 重点将放在专门的肛门肌肉的运动控制上， 排便 这项研究将扩展现有的知识， 含有GABA的假定运动神经元，称为AVL和DVB， 肛门肌肉收缩所必需的 这将通过使用 激光微束在功能上单独消除已识别的神经元 或分组，以确定它们在控制排便中的作用。 这些结果将导致一个完整的初步确定 神经元网络在这种行为中很重要。 该研究还将扩大 确定对排便重要的基因，增加了23个这样的基因， 基因已经被发现。 为此，大量的突变体在 肛门肌肉收缩的控制将被隔离。 这部分 这项研究还将使用传统的遗传方法， 显性突变体、上位性测试和突变体的详细确定 表型来表征这些基因的功能。 的最终目的 这项研究将把这种遗传分析扩展到分子水平。 现有的单克隆抗体，针对假定的 肛门肌肉运动神经元AVL和DVB，将用作免疫荧光 染色C.整座山都是美丽的。 AVL和DVB的详细结构 将在大量的排便突变体和野生型中进行比较。 这些测试将确定突变体是否改变了细胞的命运 或AVL和DVB的神经元过程引导。 其中一个基因，ex-1，是 可能是兴奋性GABA神经肌肉 AVL和DVB在肛门肌肉上形成的连接。exp-l，可能还有a 本研究中发现的其他小组类似基因将被克隆 使用几乎完整的C.线虫和DNA介导 EX-1突变体的转化拯救。 基因将被测序，其 基因产物在体内定位，并在许多组织中评估其表达。 其他影响肛门肌肉功能控制的突变体。 这些研究 将致力于了解该基因的分子功能。 拟议研究的两个特点是一般健康相关的利益。 首先，C.线虫为系统的遗传学研究提供了唯一的模式 排便，一种几乎普遍存在于后生动物中的行为， 是人类的一系列疾病 二、肛门的运动控制 C.肌肉收缩;秀丽线虫提供了一个非常好的机会， 鉴定和分析影响所鉴定GABA突触的突变体。

The goal of the proposed research is to understand the cellular, genetic, and ultimately molecular mechanisms underlying nervous system control of defecation behavior in the nematode Caenorhabditis elegans. The primary focus will be on motor control of the specialized anal muscles that mediate defecation. The study will extend the current knowledge of two GABA-containing putative motor neurons, called AVL and DVB, that are required for anal muscle contraction. This will be accomplished by using a laser microbeam to functionally eliminate identified neurons, individually or in groups, in order to determine their role in control of defecation. These results will lead to a tentative determination of the complete network of neurons important in this behavior. The study will also extend the identification of genes important for defecation, adding to the 23 such genes already identified. To this end a large set of mutants defective in control of anal muscle contraction will be isolated. This part of the study will also use classical genetic methods of reversion of existing dominant mutants, epistasis tests, and detailed determination of mutant phenotype to characterize the function of these genes. The final aim of the study will be to extend this genetic analysis to the molecular level. Existing monoclonal antibodies, which are directed against the putative anal muscle motor neurons AVL and DVB, will be used as an immunofluorescent stain in C. elegans whole mounts. The detailed structure of AVL and DVB will be compared in the large set of defecation mutants and the wild type. These tests will determine whether the mutants have altered the cell fate or neuronal process guidance of AVL and DVB. One gene, exp-1, is implicated as a possible component of an excitatory GABA neuromuscular junction made by AVL and DVB on the anal muscles. exp-l, and possibly a small set other similar genes identified in this study, will be cloned using the nearly complete physical map of C. elegans and DNA mediated transformation rescue of exp-l mutants. The gene(s) will be sequenced, its gene product localized in vivo, and its expression assessed in the many other mutants that affect control of anal muscle function. These studies will be directed at understanding the molecular function of this gene. Two features of the proposed study are of general health related interest. First, C. elegans provides the only model for the systematic genetic study of defecation, a behavior nearly universal in metazoans, and in which there are a wide range of disorders in humans. Second, motor control of anal muscle contraction in C. elegans provides an unusually good opportunity to identify and analyze mutants affecting an identified GABA synapse.