Characterization of GAD67-GFP Transgenic Mice

描述(申请人提供)：除了少数几个重要的例外，哺乳动物神经系统中的所有神经元都分为两大类：兴奋性神经元，使用谷氨酸作为神经递质；抑制性神经元，使用GABA(在某些区域还包括甘氨酸)作为神经递质。GABA能神经元在时间和空间上起着平衡兴奋和引导感觉和运动信息流的重要作用，皮质GABA能神经元的丧失或功能障碍是癫痫和退行性运动性疾病的主要因素。尽管它们发挥了关键作用，但GABA能神经元仍然知之甚少；在大多数区域，它们散布在数量更多的兴奋性神经元中，由于缺乏在活组织中可靠识别它们的手段，对它们的研究迄今受到严重阻碍。这项拟议的研究需要一种新的方法来识别和可视化活的制剂中的GABA能神经元。我们最近已经迈出了解决这一需求的第一步，通过建立几个转基因小鼠系，在其中绿色荧光蛋白的表达是以细胞特异性的方式在假定的GABA能神经元中驱动的。这些品系有可能成为研究活体制剂中GABA能神经元的一种非常强大的研究工具；然而，在将它们用于此类研究之前，需要表征转基因的分子遗传学，需要验证GFP在GABA神经元中表达的保真度，并且应该验证正常的GABA能功能。一旦这些目标实现，这些小鼠将通过NIH赞助的突变小鼠区域资源中心提供给科学界。探索性/发展性R21资助机制是适当的，因为拟议的项目将证明一种新工具--GAD67-GFP转基因小鼠的有效性和可行性，这可能会对神经科学领域产生重大影响，使研究人员能够解决关于GABA能神经元的关键问题，这些问题到目前为止很难或不可能解决。

DESCRIPTION (provided by applicant): With a few important exceptions, all the neurons in the mammalian nervous system fall into two major classes: excitatory neurons, using glutamate as a neurotransmitter, and inhibitory neurons, using GABA (and in some regions also glycine) as a neurotransmitter. GABAergic neurons play the critically important roles of counterbalancing excitation and of channeling the flow of sensory and motor information in time and in space; loss of cortical GABAergic neurons or impairment of their function is a major factor underlying epilepsy and degenerative motor diseases. Their critical roles notwithstanding, GABAergic neurons remain poorly understood; in most regions they are interspersed among the more numerous excitatory neurons, and studying them has been seriously hampered to date by the lack of a means to identify them reliably in living tissue. The need addressed by the proposed study is for a novel method to identify and visualize GABAergic neurons in living preparations. We have recently made the first step towards addressing this need, by generating several lines of transgenic mice in which expression of green fluorescent protein is driven in a cell-specific manner in putative GABAergic neurons. These lines are potentially an extremely powerful research tool for studying GABAergic neurons in living preparations; however before they can be used for such studies, the molecular genetics of the transgene needs to be characterized, the fidelity of GFP expression in GABA neurons needs to be validated, and normal GABAergic function should be verified. Once these aims are accomplished, the mice will be made available to the scientific community through the NIH-sponsored Mutant Mouse Regional Resource Centers. The Exploratory/Developmental R21 Grant mechanism of support is appropriate, because the proposed project will demonstrate the validity and feasibility of a new tool, the GAD67-GFP transgenic mouse, which could have a major impact on the field of neuroscience by allowing investigators to address crucially important questions regarding GABAergic neurons, questions which were so far difficult or impossible to address.