Myopodia (postsynaptic filopodia) participate in synaptic target recognition
Myopodia (postsynaptic filopodia) participate in synaptic target recognition
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DOI：
10.1002/neu.10180
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发表时间：
2003-04-01
期刊：
影响因子：
--
通讯作者：
Chiba, A
中科院分区：
文献类型：
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作者：
Ritzenthaler, S;Chiba, A
突触伙伴细胞通过利用多种分子线索来相互识别。在神经肌肉突触形成之前，果蝇胚胎肌肉会延伸出基于肌动蛋白的动态丝状伪足，称为“肌足”。在野生型动物中，肌足最初从肌肉表面随机延伸，但逐渐限制在运动神经元神经支配的部位，这种空间重新分布我们称之为“聚类”。先前对 Prospero 突变胚胎的实验表明，在没有运动神经元生长到肌肉区域的情况下，肌足聚集不会发生。然而，肌足聚集是由于传递轴突的一般信号还是突触伙伴之间特定相互作用的结果仍有待研究。在这里，我们研究了肌足与突触目标识别的特定事件、突触伙伴的稳定粘附的关系。我们操纵了αPS2整合素和Toll（已知会影响突触发育的分子）的胚胎表达，以特异性改变突触对已识别肌肉的靶向。然后，我们使用重要的单细胞标记方法来可视化这些动物的肌足行为。我们证明了肌足活动与突触目标识别之间存在很强的正相关性。在突触靶向被破坏的情况下，肌足聚集的频率会降低。肌足聚集似乎是由于一部分肌足粘附于神经生长锥而其余部分被消除所致。数据表明，突触后细胞在突触目标识别过程中发挥着动态作用。 (C) 2003 年 Wiley 期刊公司。
Synaptic partner cells recognize one another by utilizing a variety of molecular cues. Prior to neuromuscular synapse formation, Drosophila embryonic muscles extend dynamic actin-based filopodia called "myopodia." In wild-type animals, myopodia are initially extended randomly from the muscle surface but become gradually restricted to the site of motoneuron innervation, a spatial redistribution we call "clustering." Previous experiments with prospero mutant embryos demonstrated that myopodia clustering does not occur in the absence of motoneuron outgrowth into the muscle field. However, whether myopodia clustering is due to a general signal from passing axons or is a result of the specific interactions between synaptic partners remained to be investigated. Here, we have examined the relationship of myopodia to the specific events of synaptic target recognition, the stable adhesion of synaptic partners. We manipulated the embryonic expression of alphaPS2 integrin and Toll, molecules known to affect synaptic development, to specifically alter synaptic targeting on identified muscles. Then, we used a vital single-cell labeling approach to visualize the behavior of myopodia in these animals. We demonstrate a strong positive correlation between myopodia activity and synaptic target recognition. The frequency of myopodia clustering is lowered in cases where synaptic targeting is disrupted. Myopodia clustering seems to result from the adherence of a subset of myopodia to the innervating growth cone while the rest are eliminated. The data suggest that postsynaptic cells play a dynamic role in the process of synaptic target recognition. (C) 2003 Wiley Periodicals, Inc.