Fig. 3.

Cell shape changes during otic placode formation and assembly of the apical junctional complex. A. GPF was electroporated into otic precursors to visualise individual cells. Otic cells elongate dramatically after the 6 somite stage and continue to do so over the next hours. Bottom row: five representative cells from each stage to illustrate elongation. B. The elongation index (length/width ratio; EI) changes significantly between 6 and 7 somites (***p = 0.0007); mean values ± standard deviation are shown. C. N-CAM is absent in otic precursors at 5 somites (open arrow); it is first observed at the 9-somite stage (arrow) and intensifies thereafter. At 16 somites, double staining with phalloidin shows N-CAM (open arrow heads) localisation just basal to apical actin demarcated by the white line in bottom right panel. D. The components of adherens junctions cadherin, α-catenin and β-catenin assemble apically after the 10 somite stage.