The role of dense core vesicles in synapse formation

描述(申请人提供)：神经科学的一个中心问题是单个神经元在发育过程中是如何相互联系的。然而，突触形成的机制仍然知之甚少。许多存在于成熟突触的蛋白质和细胞器已经被确定，但这些成分如何到达新形成的突触尚不清楚。最近的两项研究，包括本实验室的一项研究，表明致密核心囊泡(DCV)在突触形成过程中将蛋白质运输到突触前活动区。DCV是一种主要类型的分泌囊，参与神经元之间的信号传递。它们分泌神经肽、激素、神经营养素和某些神经递质。这些研究现在表明，DCV在将突触前蛋白运输到新形成的突触中具有额外的作用。这项提议的目的是确定参与蛋白质运输的DCV是否与参与分泌的DCV不同，并了解DCV在突触形成中的确切作用。在前两个具体目标中，我们将使用免疫染色和光学成像来描述参与蛋白质运输的DCV的特性。在第三个具体目标中，我们将使用反义RNA来减少或消除发育中神经元中的DCV，然后研究突触形成是如何受到影响的。

DESCRIPTION (provided by applicant): A central question in neuroscience is how individual neurons connect with one another during development. However, mechanisms of synapse formation are still poorly understood. Many of the proteins and organelles present at mature synapses have been identified, but how these components arrive at newly forming synapses is not known. Two recent studies, including one from this laboratory, have implicated dense core vesicles (DCVs) in the transport of proteins to the presynaptic active zone during synapse formation. DCVs are a major type of secretory vesicle involved in signaling between neurons. They secrete neuropeptides, hormones, neurotrophins and certain neurotransmitters. These studies now suggest an additional role for DCVs in the transport of presynaptic proteins to newly forming synapses. The goals of this proposal are to determine whether the DCVs involved in protein transport differ from those involved in secretion, and to understand the precise role of DCVs in synapse formation. In the first two specific aims, we will use immunostaining and optical imaging to describe the properties of DCVs involved in protein transport. In the third specific aim, we will use antisense RNAs to reduce or eliminate DCVs in developing neurons, then examine how synapse formation is affected.