Institute of Neuroscience, Howard Hughes Medical Institute, University of Oregon, Eugene, United States.
Institute of Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, United States.
Elife. 2019 Apr 23;8:e43478. doi: 10.7554/eLife.43478.
Neural circuit assembly occurs with subcellular precision, yet the mechanisms underlying this precision remain largely unknown. Subcellular synaptic specificity could be achieved by molecularly distinct subcellular domains that locally regulate synapse formation, or by axon guidance cues restricting access to one of several acceptable targets. We address these models using two neurons: the dbd sensory neuron and the A08a interneuron. In wild-type larvae, dbd synapses with the A08a medial dendrite but not the A08a lateral dendrite. dbd-specific overexpression of the guidance receptors Unc-5 or Robo-2 results in lateralization of the dbd axon, which forms anatomical and functional monosynaptic connections with the A08a lateral dendrite. We conclude that axon guidance cues, not molecularly distinct dendritic arbors, are a major determinant of dbd-A08a subcellular synapse specificity.
神经回路的组装具有亚细胞精度，但亚细胞精度的背后机制在很大程度上仍然未知。亚细胞突触特异性可以通过分子上不同的亚细胞域来实现，这些域局部调节突触形成，或者通过轴突导向线索限制与几个可接受目标中的一个接触。我们使用两个神经元来解决这些模型：dbd 感觉神经元和 A08a 中间神经元。在野生型幼虫中，dbd 与 A08a 内侧树突形成突触，但不与 A08a 外侧树突形成突触。dbd 特异性过表达导向受体 Unc-5 或 Robo-2 会导致 dbd 轴突的偏侧化，该轴突与 A08a 外侧树突形成解剖学和功能上的单突触连接。我们得出结论，轴突导向线索，而不是分子上不同的树突分支，是 dbd-A08a 亚细胞突触特异性的主要决定因素。
