Post-Transcriptional Regulation of Cholinergic Genes

IBN-9723216果蝇胆碱能基因转录后调控PI：Toshihiro Kitamoto神经元使用各种分子作为神经递质与其靶细胞进行交流。指定特定的神经递质表型(合成和释放递质所需的酶)是有序构建和运行神经回路的基本过程，需要一组特定的神经递质特定基因的协调表达。这项研究的目的是了解两个胆碱能神经元特异性基因的调控机制，这两个基因编码胆碱乙酰转移酶(ChAT)和囊泡乙酰胆碱转运体(Vacht)，前者用于乙酰胆碱的生物合成，后者用于将乙酰胆碱包装到突触小泡中。最近已经证明，ChAT和Vacht基因被组织成一个“胆碱能”基因，后者的基因嵌套在前者中。胆碱能位点的这种独特的组织结构，在远亲物种中保守，表明新的转录后机制参与了这两个基因的协调调节。因此，该项目将特别关注以黑腹果蝇为模式生物的ChAT和Vacht基因的信使核糖核酸处理和翻译机制。首先，将使用可用于果蝇的P-元件介导的转化技术来创造携带适当报告基因的转基因动物。将通过对转化子神经系统中报告基因表达的定性和定量分析来研究ChAT和Vacht的产生机制。其次，将分离果蝇Vacht突变体，并仔细鉴定其表型。Vacht突变体和已有的ChAT突变体将用于检测改变的乙酰胆碱代谢对胆碱能基因调节的影响。这项利用分子遗传学和经典遗传学进行的研究将为调节这两个胆碱能基因协调表达的有趣的新机制提供更清晰的图景。

IBN-9723216 Post-transcriptional regulation of the Drosophila cholinergic genes PI: Toshihiro Kitamoto Neurons use a variety of molecules as neurotransmitters to communicate with their target cells. Specification of particular neurotransmitter phenotypes (enzymes required for transmitter synthesis and release) is a fundamental process for orderly construction and operation of neural circuits, and requires coordinated expression of a particular set of neurotransmitter-specific genes. The objective of this proposed research is to understand the regulatory mechanism for two cholinergic neuron-specific genes, encoding choline acetyltransferase (ChAT) for biosynthesis of acetylcholine and vesicular acetylcholine transporter (VAChT) for packaging acetylcholine into synaptic vesicles. It has recently been demonstrated that the ChAT and VAChT genes are organized into a "cholinergic" locus where the latter gene is nested within the former. This unique organization of the cholinergic locus, conserved among distantly related species, suggests that novel post-transcriptional mechanisms are involved in coordinated regulation of these two genes. The project will thus specifically focus on mRNA processing and translation mechanisms of the ChAT and VAChT genes using Drosophila melanogaster as a model organism. First, transgenic animals that carry appropriate reporter genes will be created using P-element mediated transformation technology available for Drosophila. The mechanisms for ChAT and VAChT production will be investigated by qualitative and quantitative analyses of reporter gene expression in the nervous system of the transformants. Second, Drosophila VAChT mutants will be isolated and their phenotypes will be carefully characterized. VAChT mutants together with already available ChAT mutants will be used to examine the effects of altered acetylcholine metabolism on regulation of the cholinergic genes. The proposed research using molecu lar and classical genetics will provide a clearer picture of interesting new mechanisms regulating coordinated expression of the two cholinergic genes.