Fig. 1: Snapshots of cells in the layer.
a Nematic ordering of cell shape in a confluent cell monolayer. Red lines indicate the nematic directors n, which lie along the long axis of a cell, and which tend to align parallel. b Cell shape orientations around a +1/2 topological defect are shown in yellow. c Cell shape orientations around a −1/2 topological defect are shown in green. d Geometry of the MDCK monolayers used in the experiments. e Example of a typical experiment measuring the long axis of cell shape orientation, n, (red lines) in an MDCK monolayer. f A typical set of results from experiments measuring the orientation of maximum contractile stress m (white lines) overlaid on the orientations of cell shape, n (red lines). In (e–f), the lengths of the red (white) lines are proportional to the deviation of the cell aspect ratio from unity (magnitude of the contractile stress). Experiments are repeated independently 11 times with similar results.
