TY - JOUR T1 - Cell-type specific mechanical response and actomyosin dynamics in the developing <em>Drosophila</em> retina JF - bioRxiv DO - 10.1101/558593 SP - 558593 AU - Laura Blackie AU - Michael F. Staddon AU - Shiladitya Banerjee AU - Franck Pichaud Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/02/22/558593.abstract N2 - Organs consist of multiple cell types that assemble into multicellular structures, or physiological units, to support organ function. However, the mechanisms that regulate cell positioning and shape during physiological unit development remain elusive. To address this issue, we made use of the Drosophila ommatidium, which is the physiological unit of the retina. We show that during ommatidium assembly, the apical-medial cytosolic contractile actomyosin cytoskeleton plays a preeminent role in determining cell shape. In addition, we found that this contractile machinery underpins the capacity of cells to respond to mechanical perturbations. However, not all ommatidial cells are mechanically coupled. Our results argue that the ommatidial cells that present the highest velocity of Myosin-II particle displacement and the fastest area fluctuations during morphogenesis are also more prone than others to deformation in response to mechanical tension. Further, to understand the physical origin of the cell-type specific response to mechanical perturbation, we developed a tension-elasticity model for ommatidial shape. Using this model and by manipulating cell contractility, our work reveals that differences in cell mechanical properties can coordinate cell type specific shape dynamics. ER -