Disruption of both the dispersion and deformation pathways causes nuclear and cell packing defects. (A) 3D reconstruction of cell membranes (pink) and nuclei (blue) from live imaging data of non-deformable vehicle-injected (kuk ctrl, top panel) and non-deformable colchicine-injected kuk (kuk MT-, bottom panel) embryos (related to Video 8). (B) Still images showing higher nuclear crowding in apical layers in kuk MT- embryos as compared with kuk ctrl embryos at +20 min (related to Video 9). (C) Still images showing a rapid tug-of-war between nuclei to occupy apical space (related to Video 10). The nucleus marked by arrow initially basal to the adjacent nuclei (0 s) is pushed to the apical position (75 s) and is again forced to sink basally (225 s) due to the competition to occupy limited apical space. (D) SD of cell areas for given apical–basal plane in control (luciferase shRNA) (blue), kuk (red), kuk ctrl (black), and kuk MT- (yellow) embryos; n = 961 cells for, n = 580 cells for kuk, n = 1,078 cells for kuk ctrl, and n = 695 cells for kuk MT- from k = 3 embryos for each background. 0 μm indicates nuclear midplane, negative values indicate apical, and positive values indicate basal to the nuclear midplane. The measured n values are regardless of time points. For B and C, scale bar = 10 and 5 µm, respectively.