Post-Transcriptional Regulation of Cholinergic Genes

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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.