Fig. S1

Polarized orientation of posterior somite cells is not affected in cdh2^-/- embryos; related to Figure 1. (A) Phalloidin was used to outline cell cortices in cdh2^-/- embryos and wild-type siblings. (B) The polarized orientation of cells with respect to the somite boundary was determined by measuring the angle θ between fit ellipses of cell traces and the somite border. The alignment was then calculated using the absolute value of 90-θ, which is small when the cell is aligned along the Anterior-Posterior axis (i.e. perpendicular to the somite border) (D) and large when the cell is aligned with the Medial-Lateral axis (i.e. parallel to the somite border) (E). Though the aspect ratio is reduced in row 4 cells in cdh2^-/- (Figure 1E), the polarized orientation in these cells is not affected by loss of cdh2 (p>0.05). A modest change in polarized orientation is seen in row 1 cells (p<0.05). Scale bar = 20 µm.