Perinuclear MT networks are more stable than centrosomal MT pools. (A) Orthogonal projection of cells and nuclei at 0 and 20 min GBE, highlighting nuclear dispersion at later time points. (A′) Measurement of the fraction of nuclei in the apical 10 μm of cells showing the displacement of apically located nuclei to more basal regions as GBE proceeds (mean ± SEM); n = 306, 355, and 263 nuclei at 0, 10, and 20 min, respectively. (B) Still frames from live imaging MTs (Jupiter:GFP) prior to GBE (cellularization) showing MTs transitioning from a centrosomal to nc networks. Arrows and arrowheads indicate centrosomal and nc MT pools, respectively. (C) Still frames showing MTs (green) and centrosomes (Asl, magenta) indicating the depletion of centrosomal MT pool at 20 min into GBE. Arrowheads point to centrosomal MTs. (D) Orthogonal projection of acetylated MT (green) and nuclei (DAPI, magenta), highlighting stable MTs in apical nuclear regions during GBE. (D′) Orthogonal projection showing acetylated MT (magenta) is present at perinuclear and juxtanuclear MTs. (E) Orthogonal projection of MTs (green) and nuclei (magenta) from embryos injected with vehicle control (top) and colchicine (bottom), showing colchicine-resistant perinuclear MT pools. Scale bar = 5 μm for (A, C, D, D′, and E), and 3 μm for (B). Statistical significance was calculated using the Mann–Whitney U-test. ****P < 0.0001.