Chen Yixu, Cameron Scott, Chang Wen-Tzu, Rao Yong
McGill Centre for Research in Neuroscience, Department of Neurology and Neurosurgery, McGill University Health Centre, 1650 Cedar Avenue, Montreal, QC, H3G 1A4, Canada.
Integrated Program in Neuroscience, McGill University Health Centre, 1650 Cedar Avenue, Montreal, QC, H3G 1A4, Canada.
Mol Brain. 2017 May 23;10(1):17. doi: 10.1186/s13041-017-0299-6.
Proper recognition between axons and glial processes is required for the establishment of axon ensheathment in the developing nervous system. Recent studies have begun to reveal molecular events underlying developmental control of axon-glia recognition. In our previous work, we showed that the transmembrane protein Borderless (Bdl) is specifically expressed in wrapping glia (WG), and is required for the extension of glial processes and the ensheathment of photoreceptor axons in the developing Drosophila visual system. The exact mechanism by which Bdl mediates axon-glia recognition, however, remains unknown. Here, we present evidence showing that Bdl interacts with the Ig transmembrane protein Turtle (Tutl). Tutl is specifically expressed in photoreceptor axons. Loss of tutl in photoreceptors, like loss of bdl in WG, disrupts glial extension and axon ensheatment. Epistasis analysis shows that Tutl interacts genetically with Bdl. Tutl interacts with Bdl in trans in cultured cells. We propose that Tutl interacts with Bdl in mediating axon-glia recognition for WG extension and axon ensheathment.
在发育中的神经系统中，轴突与神经胶质突起之间的正确识别是轴突被包裹所必需的。最近的研究开始揭示轴突 - 神经胶质识别发育控制背后的分子事件。在我们之前的工作中，我们表明跨膜蛋白Borderless（Bdl）在包裹性神经胶质细胞（WG）中特异性表达，并且是发育中的果蝇视觉系统中神经胶质突起延伸和光感受器轴突被包裹所必需的。然而，Bdl介导轴突 - 神经胶质识别的确切机制仍然未知。在这里，我们提供证据表明Bdl与免疫球蛋白跨膜蛋白Turtle（Tutl）相互作用。Tutl在光感受器轴突中特异性表达。光感受器中tutl的缺失，就像WG中bdl的缺失一样，会破坏神经胶质延伸和轴突被包裹。上位性分析表明Tutl与Bdl发生遗传相互作用。在培养细胞中，Tutl与Bdl发生反式相互作用。我们提出Tutl与Bdl相互作用，介导WG延伸和轴突被包裹的轴突 - 神经胶质识别。
