Nuclei disperse to different apical–basal planes during tissue extension. Video displays nuclei (at a given plane) from a control embryo labeled by midplane depth from the apical surface. At the beginning of GBE, nuclei are located in a common plane (yellow) color; as intercalation initiates, nuclei disperse in apical (hotter, red colors) and basal directions (cooler, blue colors). Nuclei that move completely out of the imaging plane are not displayed from that time point forward. Images in videos were acquired at a rate of 15 s per frame and displayed at 12 frames per second. Scale bar = 10 μm.
