RT Journal Article SR Electronic T1 Epithelial colonies in vitro elongate through collective effects JF bioRxiv FD Cold Spring Harbor Laboratory SP 755181 DO 10.1101/755181 A1 Jordi Comelles A1 SS Soumya A1 Linjie Lu A1 Emilie Le Maout A1 S. Anvitha A1 Guillaume Salbreux A1 Frank Jülicher A1 Mandar M. Inamdar A1 Daniel Riveline YR 2020 UL http://biorxiv.org/content/early/2020/11/30/755181.abstract AB Epithelial tissues of the developing embryos elongate by different mechanisms, such as neighbor exchange, cell elongation, and oriented cell division. Since autonomous tissue self-organization is influenced by external cues such as morphogen gradients or neighboring tissues, it is difficult to distinguish intrinsic from directed tissue behavior. The mesoscopic processes leading to the different mechanisms remain elusive. Here, we study the spontaneous elongation behavior of spreading circular epithelial colonies in vitro. By quantifying deformation kinematics at multiple scales, we report that global elongation happens primarily due to cell elongations, and its direction correlates with the anisotropy of the average cell elongation. By imposing an external time-periodic stretch, the axis of this global symmetry breaking can be modified and elongation occurs primarily due to orientated neighbor exchange. These different behaviors are confirmed using a vertex model for collective cell behavior, providing a framework for understanding autonomous tissue elongation and its origins.Competing Interest StatementThe authors have declared no competing interest.