Résumé
Epithelial tubules consist of a curved monolayer of epithelial cells surrounding a central lumen. They are the structural unit of many organs including the kidney and lumen shape and size maintenance is essential for their function. Cell division controls a vast majority of proliferative epithelial tissue morphogenesis. Cytokinesis, the last stage of cell division, is essential to trigger and control de novo lumen formation but its contribution to the maintenance of kidney tubule organization remains unknown. Combining spherical 3D cultures of MDCK cells and the zebrafish pronephros as an in vivosystem, we characterize here how cytokinesis dynamically and spatially organizes in a 3D epithelial environment and show that controlled furrow constriction in cytokinesis is required for lumen shape and size maintenance. Using 3D culture of MDCK cells, we show that perturbations of furrowconstriction in cytokinesis, without preventing cytokinetic abscission, lead to defects in lumen shape and size. Importantly, taking advantage of 3D time-lapse imaging of the zebrafish pronephros, we show that furrow constriction perturbations lead to kidney tubule enlargement in vivo due to increased lumen size. We further show that lumen enlargements occur in proliferative regions of the pronephros and can be rescued using cell cycle inhibitors that prevent cell division. This demonstrates that defects occurring in division are responsible for kidney lumen size defects. Altogether, our findings show that proper control of furrow constriction during cell division ensures lumen shape and size maintenance and thus proper morphogenesis of kidney epithelial tubule.