Different actin-dependent mechanisms of apical nuclear migration are linked to cell and tissue shape. (A) Schematic of the position and morphology of hindbrain and retinal neuroepithelia. (A’) Distribution of phalloidin (actin, gray), p-Myo (active [phosphorylated] myosin; lookup table indicates minimal and maximal signal values), and DAPI (nuclei, magenta) in hindbrain and retinal neuroepithelia. (B) Normalized average intensity distributions of phalloidin, p-Myo, and DAPI along the apicobasal axis of hindbrain and retinal neuroepithelium. The mean of all samples is shown; error bars: SD. (C) Schematic of the position and morphology of MHBS and MHBC neuroepithelia. MHBS: dark green; MHBC: dark blue. (D) Distribution of phalloidin (actin, gray), p-Myo (lookup table indicates minimal and maximal signal values), and DAPI (nuclei, magenta) in MHBS and MHBC neuroepithelia. (E) Normalized average intensity distributions of phalloidin, p-Myo, and DAPI signal in MHBC and MHBS. The mean of all samples is shown; error bars: SD. (F) MHBS and MHBC nuclear trajectories compared with hindbrain and retinal trajectories. Hindbrain and retinal trajectories correspond to Fig. 1 D. (G) Directionality ratios of MHBS and MHBC nuclei. The mean of all tracks is shown, with hindbrain and retinal data corresponding to Fig. 1 F. Error bars: SD. Final directionality ratios: MHBS = 0.67 ± 0.01, MHBC = 0.53 ± 0.01. (H) Average nuclear aspect ratio change in MHBS and MHBC with the onset of G2 (P = 0.0221, Mann-Whitney test). Hindbrain (HB) and retinal (R) aspect ratio changes correspond to Fig. 2 D. Error bars: SD. (I) Actin distribution before and during apical migration in MHBS and MHBC cells (shown is the maximum projection of the 3D stack’s central five z planes; Video 9). mKate2-PCNA labels nuclei (gray), and GFP-UtrophinCH labels actin (lookup table indicates minimal and maximal GFP-UtrophinCH signal values). Scale bars: 10 µm (A), 5 µm (D and I).