Fig. 2

Pulsatile contractions are a cell-level behavior but induce area changes across neighbors (A) Left: time-lapse sequence of pulsing epithelial cells expressing LifeAct-GFP. Time is in minutes and seconds MM:SS. Scale bar represents 20 μm. Third panel represents flow fields where the length of the arrows is proportional to convergence/divergence. Lower panel represents convergence/divergence maps where convergence is blue and divergence is red. Color code gives the amplitude of convergence/divergence in s−1. Dashed red line represents the outline of tracked pulsing cell. Right: scatter dot graph correlating the area fold change (left axis; gray line as given by segmentation in Tissue Analyzer), divergence from a pulsing cell (right axis; red line), and neighboring cells (right axis; blue line). Dots represent average values of convergence/divergence of 182 pulses ± SEM in N = 3 larvae. (B) Time-lapse sequence of epithelial cells expressing LifeAct-GFP. Overlaid color map represents convergence/divergence field where blue is convergence and red is divergence. Red arrow indicates the first pulsing cell, and white arrow indicates neighboring cell that pulses afterward. Scale bar represents 20 μm. Time is in minutes and seconds MM:SS. See also Video S2 and Figures S2B and S2C. (C) Quantification of the duration, relative amplitude, and relative area loss of single-cell pulses versus multi-cell pulses. Analyses were performed on n = 10 cells/category over N = 3 larvae. (D) Left: time-lapse sequence of MIPs of larva tails where epithelial cells express NTR-mCherry (magenta) and LifeAct-GFP (green). Dotted white lines represent the contour of the tails. Time is in hours. Scale bar represents 100 μm. Right: scatter dot graph correlating the area fold change of DMSO-treated larvae and MTZ-treated larvae. Analysis was performed on N = 10 larvae/condition, and dots represent average values ± SEM.