Browsing by Author "Guzman-Palma, Pablo"

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    Autocrine/Paracrine Slit-Robo Signaling Controls Optic Lobe Development in Drosophila melanogaster
    (2022) Gonzalez-Ramirez, M. Constanza; Rojo-Cortes, Francisca; Candia, Noemi; Garay-Montecinos, Jorge; Guzman-Palma, Pablo; Campusano, Jorge M. M.; Oliva, Carlos
    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.
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    Cell segregation and boundary formation during nervous system development
    (2021) Constanza Gonzalez-Ramirez, M.; Guzman-Palma, Pablo; Oliva, Carlos
    The development of multicellular organisms involves three main events: differentiation, growth, and morphogenesis. These processes need to be coordinated for a correct developmental program to work. Mechanisms of cell segregation and the formation of boundaries during development play essential roles in this coordination, allowing the generation and maintenance of distinct regions in an organism.These mechanisms are also at work in the nervous system. The process of regionalization involves first the patterning of the developing organism through gradients and the expression of transcription factors in specific regions. Once different tissues have been induced, segregation mechanisms may operate to avoid cell mixing between different compartments.Three mechanisms have been proposed to achieve segregation: (1) differential affinity, which mainly involves the expression of distinct pools of adhesion molecules such as members of the cadherin superfamily; (2) contact inhibition, which is largely mediated by Eph-ephrin signaling; and (3) cortical tension, which involves the actomyosin cytoskeleton. In many instances, these mechanisms collaborate in cell segregation. In the last three decades, there have been several advances in our understanding of how cell segregation and boundaries participate in the development of the nervous system. Interestingly, as in other aspects of development, the molecular players are remarkably similar between vertebrates and invertebrates. Here we summarize the main concepts of cell segregation and boundary formation, focusing on the nervous system and highlighting the similarities between vertebrate and invertebrate model organisms.