Campos A R, Lee K J, Steller H
Department of Biology, McMaster University, Hamilton, Ontario, Canada.
J Neurobiol. 1995 Nov;28(3):313-29. doi: 10.1002/neu.480280305.
We used confocal microscopy in conjunction with specific antibodies and enhancer trap strains to investigate the development of specific neuronal connections in a simple model system, the larval visual system of Drosophila. We find that the establishment of axonal projections from the larval photoreceptor neurons to their central nervous system targets involves a series of discrete steps. During embryogenesis, the larval optic nerve contacts several different cell types, including optic lobe pioneer (OLP) neurons and a number of glial cells. We demonstrate that OLP neurons are present and project normally in glass (gl) mutant embryos in which the larval optic nerve fails to develop, suggesting that they do not depend on interactions with the larval optic nerve for differentiation and proper axonal projection. The OLPs fail to differentiate properly is disconnected (disco) mutant embryos, where appropriate connections between the larval optic nerve and its targets in the brain are not formed. The disco gene is expressed in the OLPs and may therefore act autonomously to direct the differentiation of these cells. Taken together, our results suggest that the OLPs act as an intermediate target required for the establishment of normal optic nerve projection and connectivity.
我们使用共聚焦显微镜结合特异性抗体和增强子捕获菌株，在一个简单的模型系统——果蝇幼虫视觉系统中研究特定神经元连接的发育。我们发现，幼虫光感受器神经元向其中枢神经系统靶标的轴突投射的建立涉及一系列离散步骤。在胚胎发生过程中，幼虫视神经接触几种不同的细胞类型，包括视叶先驱（OLP）神经元和一些神经胶质细胞。我们证明，在玻璃（gl）突变体胚胎中，OLP神经元存在且正常投射，而在这些胚胎中幼虫视神经无法发育，这表明它们的分化和正确的轴突投射不依赖于与幼虫视神经的相互作用。在断开连接（disco）突变体胚胎中，OLP不能正常分化，在这些胚胎中，幼虫视神经与其在大脑中的靶标之间没有形成适当的连接。disco基因在OLP中表达，因此可能自主发挥作用来指导这些细胞的分化。综上所述，我们的结果表明，OLP作为建立正常视神经投射和连接所需的中间靶标。
