Expression of synaptotagmin in Drosophila reveals transport and localization of synaptic vesicles to the synapse.
Expression of synaptotagmin in Drosophila reveals transport and localization of synaptic vesicles to the synapse.
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发表时间：
1993-08
期刊：
影响因子：
4.6
通讯作者：
J. Littleton;H. Bellen;M. Perin
中科院分区：
文献类型：
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作者：
J. Littleton;H. Bellen;M. Perin
突触结合蛋白是一种突触小泡特异性整合膜蛋白，已被认为在突触小泡对接和融合中发挥关键作用。通过监测突触结合蛋白在发育过程中的细胞和亚细胞分布，可以研究突触小泡的定位和运输以及突触形成。我们已经开始研究果蝇神经发生过程中突触结合蛋白的表达，以便跟踪突触形成之前和期间的突触小泡运动，以及定位果蝇中的突触位点。整体胚胎的原位杂交表明，在神经突生长和突触形成过程中，突触结合蛋白（syt）信息存在于所有周围神经系统神经元和许多（如果不是全部）中枢神经系统神经元的细胞体中，以及成熟神经元中。使用突触结合蛋白特异性抗血清进行的免疫细胞化学染色表明，该蛋白存在于果蝇生命周期中胚带收缩后的所有阶段。在胚胎中，突触结合蛋白仅短暂地定位于神经元的细胞体，并在轴突发生过程中沿着轴突快速运输。突触形成后，突触结合蛋白在所有可识别的突触接触位点以点状形式积累，表明突触结合蛋白在突触功能中的一般作用。在胚胎和幼虫中，最强烈的染色出现在腹神经索和大脑背侧的两条宽阔的纵向束上，以及周围的神经肌肉接头处。在成人头部中，突触结合蛋白定位神经粒细胞中预计会出现突触的离散区域。这些数据表明，突触小泡在突触形成之前存在于轴突中，并且在突触形成之后变得仅限于突触接触位点。由于在哺乳动物中已报道了突触结合蛋白的类似表达模式，因此我们提出突触结合蛋白的功能和在突触形成之前和之后控制突触小泡定位的机制在无脊椎动物和脊椎动物物种中是保守的。标记果蝇突触的能力应该有助于突触形成和功能的研究，为剖析这些过程背后的分子机制提供了一种新工具。
Synaptotagmin is a synaptic vesicle-specific integral membrane protein that has been suggested to play a key role in synaptic vesicle docking and fusion. By monitoring Synaptotagmin's cellular and subcellular distribution during development, it is possible to study synaptic vesicle localization and transport, and synapse formation. We have initiated the study of Synaptotagmin's expression during Drosophila neurogenesis in order to follow synaptic vesicle movement prior to and during synapse formation, as well as to localize synaptic sites in Drosophila. In situ hybridizations to whole-mount embryos show that synaptotagmin (syt) message is present in the cell bodies of all peripheral nervous system neurons and many, if not all, central nervous system neurons during neurite outgrowth and synapse formation, and in mature neurons. Immunocytochemical staining with antisera specific to Synaptotagmin indicates that the protein is present at all stages of the Drosophila life cycle following germ band retraction. In embryos, Synaptotagmin is only transiently localized to the cell body of neurons and is transported rapidly along axons during axonogenesis. After synapse formation, Synaptotagmin accumulates in a punctate pattern at all identifiable synaptic contact sites, suggesting a general role for Synaptotagmin in synapse function. In embryos and larvae, the most intense staining is found along two broad longitudinal tracts on the dorsal side of the ventral nerve cord and the brain, and at neuromuscular junctions in the periphery. In the adult head, Synaptotagmin localizes the discrete regions of the neurophil where synapses are predicted to occur. These data indicate that synaptic vesicles are present in axons before synapse formation, and become restricted to synaptic contact sites after synapses are formed. Since a similar expression pattern of Synaptotagmin has been reported in mammals, we propose that the function of Synaptotagmin and the mechanisms governing localization of the synaptic vesicle before and after synapse formation are conserved in invertebrate and vertebrate species. The ability to mark synapses in Drosophila should facilitate the study of synapse formation and function, providing a new tool to dissect the molecular mechanisms underlying these processes.