Figure 4.

Analysis of cell shape changes in the early stage of Drosophila ventral furrow formation. (Left) Representative time-lapse images (red box in (A)) showing deformation of mesoderm cells during apical modulation. The cell shape outlined in green is analyzed in (B) and (C), where each symbol denotes the measurements obtained from an embryo. The colors of the symbols indicate the time frame, and the lines are the fitting curves, obtained by using the nonlinear least-squares Marquardt-Levenberg algorithm, which serve as visual guides. The initial time point is chosen arbitrarily before the onset of apical constriction of the mesoderm cells. The details of the experimental setup are provided in Appendix D. To see this figure in color, go online.