Postembryonic development of drosophila motoneurons

描述（由申请人提供）：正常的脑功能需要精确的树突形状和电特性。神经元必须在最初的发育过程中获得这些特性，并在整个生命过程中保持这些特性，除非在需要功能可塑性的情况下。本研究的长期目标是了解神经元活动在调节树突形状和电压门控离子通道分布中的作用。我们已经开发出的技术，以下的树突发育过程中确定的运动神经元的变态在遗传上听话的模式生物，果蝇，并证明了活动水平影响树突发育显着。神经元活性和钙依赖性转导途径可以在体内和原代细胞培养中精确操纵。具体目标是：1。确定在变态过程中飞行运动神经元的功能属性是如何被改变的。将采用全细胞电流和电压钳技术。2.研究不同时期电压门控性钾通道和钙通道的表达形式、在运动神经元内的分布及类固醇激素对其的调节。通道表达将通过RT-PCR测量，并且分布通过迫使用四聚-半胱氨酸基序标记的通道的表达来确定。3.表征树突发育的活性依赖性调节。通过驱动修饰的离子通道的表达以及通过生长和功能的体内和体外测量确定的效果，将增加或减少所识别的运动神经元的活动模式。4.确定钙依赖性信号通路的作用。活动依赖性钙内流的来源和性质将使用遗传编码的钙指标来确定，神经元离子通道的高度保守性和调节发育过程的分子途径表明，从该模型系统中获得的基本信息将提供对人类健康的见解。与公共卫生的相关性：正常的大脑功能需要神经元形成精确的树突结构和确定的电特性阵列。中风和疾病，如癫痫，可能导致这些属性的维护不当。拟议的研究旨在描述确保这些特征的适当发展和维持的机制。

DESCRIPTION (provided by applicant): Normal brain function requires precise dendritic shape and electical characteristics. Neurons must acquire these properties during initial development and maintain them through life, except under circumstances where functional plasticity is required. The long-term objectives of this project are to understand the role of neuronal activity in regulating dendritic shape and distribution of voltage-gated ion channels. We have developed techniques for following the dendritic development of identified motoneurons during metamorphosis in the genetically-tractable model organism, Drosophila melanogaster, and demonstrated that activity levels influence dendritic development significantly. Neuronal activity and calcium-dependent transduction pathways can be manipulated precisely, both in vivo and in primary cell culture. Specific aims are: 1. To determine how the functional attributes of identified flight motoneurons are modified during metamorposis. Whole-cell current and voltage-clamp techniques will be employed. 2.To determine which forms of voltage-gated potassium and calcium channels are expressed at different stages, their distributions within the motoneuron and their regulation by steroid hormone. Channel expression will be measured by RT- PCR, and distribution determined by forcing the expression of channels tagged with a tetrad-cystiene motif. 3. Characterize the acitivity-dependent regulation of dendritic development. The activity patterns of identified motoneurons will be increased or decreased by driving the expression of modified ion channels and the effect determined with both in vivo and in vitro measurements of growth and function. 4. Determine the role of calcium-dependent signalling pathways. The source and nature of activity-dependent calcium influx will be determined using genetically-encoded calcium indicators, the highly conserved nature of neuronal ion channels and the molecular pathways that regulate developmental processes suggests that basic information derived from this model system will provide insights into human health. Relevance to public health: Normal brain function requires that neurons develop a precise dendritic structure and a defined array of electrical characteristics. Stroke and diseases, such as epilepsy, can result in improper maintenance of these properties. The proposed research seeks to characterize mechanisms that ensure proper development and maintenance of these characteristics.