Distinct actomyosin pools are involved in apical nuclear migration in hindbrain and retina. (A) Actin distribution before and during apical migration in hindbrain and retinal cells (shown is the central z plane of a 3D stack; Video 4). mKate2-PCNA labels nuclei (gray), GFP-UtrophinCH labels actin (lookup table indicates minimal and maximal GFP-UtrophinCH signal values). Scale bar: 5 µm. (B) Region basal of the nucleus where GFP-UtrophinCH signal intensity was measured in the cells depicted in A. (B’) Normalized average intensity distribution of GFP-UtrophinCH signal. The mean profile of all G2 time points is shown; error bars: SD. (C) Region where average GFP-UtrophinCH fluorescence intensity was measured basally to the nucleus in a z projection summing the intensities of all slices. (D) Pooled fluctuation frequencies of instantaneous velocity, nuclear aspect ratio, and basal actin intensity for the same retinal cell. Error bars: SD. P = 0.46 and P = 0.05 for the pairs velocity-actin and aspect ratio–actin, respectively, Mann-Whitney test. (E) Cross-correlation analysis between the fluctuations in basal actin and instantaneous velocity, as well as basal actin and nuclear aspect ratio.