Fig. 1

Live imaging and cell area and myosin measurements. a–c Confocal dorsal projections of amnioserosa tissues carrying membrane (DECadGFP, red) and myosin (zipperYFP, green) markers during early (a), slow (b) and fast (c) dorsal closure. Insets represent dorsal views of Drosophila embryos for the corresponding dorsal closure stages. d Segmentation of amnioserosa tissue, with segmented cells coloured according to myosin fluorescence intensity levels. e Apical area and g myosin fluorescence intensity evolution for a sample cell in the dataset. The area trend and myosin minima trends are shown in orange; time t=0 corresponds to the onset of slow dorsal closure. Resulting f apical strain and h rescaled myosin for the raw signals (e) and (g), respectively. i Cartoon showing three classes of relative myosin phase correlation used in the neighbour analysis. Arrows show the specific effect of neighbour myosin phase, all other things being equal, on the movement of membranes, which is the outcome of the balance between the relative contractile forces within each cell. The apicomedial region within which myosin fluorescence intensity is measured, excluding junctional myosin, is shown enclosed by the grey dashed line in cell in left-hand cartoon. j For all fluctuating cells that have a fluctuating neighbour, the dependence of the rate of change in area of the focal cell on its myosin phase is shown, broken down by the relative myosin phase of the focal cell and its neighbour. Relative myosin phase is classified as correlated, uncorrelated or anti-correlated (see also ‘Methods’ and Additional file 4: Figure S4). Dotted lines show 95 % confidence intervals