Autocrine/Paracrine Slit-Robo Signaling Controls Optic Lobe Development in Drosophila melanogaster

Cell segregation mechanisms play essential roles during the development of the central nervous system (CNS) to support its organization into distinct compartments. The Slit protein is a secreted signal, classically considered a paracrine repellent for axonal growth through Robo receptors. However, its function in the compartmentalization of CNS is less explored. In this work, we show that Slit and Robo3 are expressed in the same neuronal population of the Drosophila optic lobe, where they are required for the correct compartmentalization of optic lobe neuropils by the action of an autocrine/paracrine mechanism. We characterize the endocytic route followed by the Slit/Robo3 complex and detected genetic interactions with genes involved in endocytosis and actin dynamics. Thus, we report that the Slit-Robo3 pathway regulates the morphogenesis of the optic lobe through an atypical autocrine/paracrine mechanism in addition to its role in axon guidance, and in association with proteins of the endocytic pathway and small GTPases.

Automated summary

In this study, the role of the Slit-Robo3 signaling pathway in the morphogenesis of the Drosophila optic lobe was investigated. It was found that Slit and Robo3 are expressed in the same neuronal population and they regulate the compartmentalization of the optic lobe through an autocrine/paracrine mechanism. Furthermore, interactions with genes involved in endocytosis and actin dynamics were detected, indicating the involvement of the endocytic pathway and small GTPases in this process. This study reveals the important role of the Slit-Robo3 pathway in CNS development.