Matrigel patterning reflects multicellular contractility
Fig 5
Quantitative evaluation of the gel patterning assay with A431 cells.
A: Time-dependent cumulative distribution of cell-free area (hole) sizes: the fraction of holes that are smaller than the x-axis value. Initial cell coverage was 66%, distribution functions were compiled from n = 3 independent recordings and a total of 9 microscopic fields. The dotted line shows a lognormal distribution, serving as a guide to the eye. B: Expansion rate of cell-free areas, binned according to size. We identified areas that did not merge with adjacent holes during a 30 minute time interval, and determined the change in their area. Larger areas grow faster as the linear regression fit indicates (correlation coefficient: 0.94). Error bars indicate SEM. Data was pooled and binned from n = 3 independent sets of experiments. C: Comparison of patterning started at various initial cell densities. Time dependence of the mean hole size , compared to the initial value as
. Blue, green and red lines correspond to cultures seeded with initial cell coverage at 40%, 64% and 80% confluency, respectively. The growth rate of holes r decreases with increasing the initial cell density. Error stripes represent SEM, calculated from n = 3 independent sets of microscopic fields. D: Cell density-dependence of the hole size growth rate r, calculated from the curves depicted in panel C by linear fitting. Error bars indicate SEM.