Neph/Nephrin-like adhesion and tissue level pulling forces regulate cell intercalation during Drosophila retina development

Abstract

2 SUMMARYIntercalation between neighboring cells contributes to shaping epithelial tissues and is regulated by the contractile actomyosin cytoskeleton. While intercalation typically occurs over minutes, instances of much slower cell intercalation have been reported during organogenesis. This is observed, for example, for the four glial-like cone cells (CC) that intercalate during Drosophila retinal patterning. Here we show that Myosin-II activity in the CCs is largely dispensable for their intercalation. Instead, we find that differential activity of the Notch-signaling pathway within the CC quartet regulates intercalation, which also depends on the cell adhesion proteins Roughest and Hibris.In addition, mathematical modeling predicts that forces external to the intercalating CC quartet are necessary for intercalation. Consistent with this prediction we show that the surrounding primary pigment cells are under significant contractile tension.Altogether, our work elucidates a novel mode of cell intercalation that relies on Neph/Nephrin-like adhesion and forces external to the intercalating cells.3

Neuronal immunoglobulin superfamily cell adhesion molecules in epithelial morphogenesis: insights fromDrosophila

“…It has been proposed that the Rst-Hbs interaction regulates the activity of the GTPase activating protein Arf6 through the adaptor protein Cindr to inhibit cellular extensions at Rst-Hbs defined cell-cell junctions. Intercalation of these cells is independent of myosin II activity in intercalating cells [100]. Computational modelling predicts that tissue-contractile forces are required for intercalation.…”