Genetic Regulation of Acetylcholine Synthesis

描述（由申请人提供）：本提案的目的是继续对土壤线虫秀丽隐杆线虫中乙酰胆碱合成和包装进行分子和遗传分析。这些研究集中在三个基因和蛋白质：cha-1是胆碱乙酰转移酶（ChAT）的结构基因，ChAT是合成神经递质乙酰胆碱的酶; unc-17是编码突触囊泡乙酰胆碱转运蛋白（VAChT）的基因; cho-1编码质膜胆碱高亲和力转运蛋白（CHT）。其中两个基因，cha-1和unc-17，紧密相连并定义了“胆碱能基因位点”。C.由于其简单的神经系统，易于遗传和分子分析，以及DNA介导的转化技术的可用性，线虫被用于这些研究。具体目标包括开发用于定量胆碱能介导的行为的标准化灵敏测定系统，分析多种cha-1转录物和多种ChAT同种型以确定其在ChAT功能中的作用，分离额外的cho-1等位基因和cho-1的基因外抑制因子，确定磷酸化在三种胆碱能蛋白的定位和功能中的作用，以及（与其他两个实验室合作）线虫和哺乳动物ChAT和VAChT的结构-功能研究。这些研究的结果将阐明神经末梢内用于协调神经递质供应和需求的机制。虽然这是基础研究，但它显然与健康有关，因为乙酰胆碱代谢和/或胆碱能功能的改变已在许多神经和精神疾病中被确定，包括先天性肌无力综合征，阿尔茨海默病和抑郁症。

DESCRIPTION (provided by applicant): The purpose of this proposal is to continue molecular and genetic analysis of acetylcholine synthesis and packaging in the soil nematode Caenorhabditis elegans. These studies focus on three genes and proteins: cha-1 is the structural gene for choline acetyltransferase (ChAT), the enzyme which synthesizes the neurotransmitter acetylcholine; unc-17 is the gene which encodes the synaptic vesicle acetylcholine transporter (VAChT); and cho-1 encodes the plasma membrane choline high-affinity transporter (CHT). Two of these genes, cha-1 and unc-17, are tightly linked and define the "cholinergic gene locus". C. elegans is being used for these studies because of its simple nervous system, its ease of genetic and molecular analysis, and the availability of DNA-mediated transformation techniques. The specific aims include development of a standardized sensitive assay system for quantifying cholinergic-mediated behavior, analysis of multiple cha-1 transcripts and multiple ChAT isoforms to determine their roles in ChAT function, isolation of additional cho-1 alleles and extragenic suppressors of cho-1, determining the role of phosphorylation in localization and function of the three cholinergic proteins, and (in collaboration with two other laboratories) structure-function studies of nematode and mammalian ChAT and VAChT. The results of these studies will elucidate the mechanisms used within nerve terminals to coordinate neurotransmitter supply and demand. Although this is basic research, it is clearly relevant to health, since alterations in acetylcholine metabolism and/or cholinergic function have been identified in many neurological and psychiatric disorders, including congenital myasthenic syndromes, Alzheimers disease, and depression.