Immunostaining was performed using similar procedures as described previously 11 (link). Fixation to control for the effect of Ciliobrevin D was done in bulk, as described in fig S3. The fixation of eggs with injected beads, was performed in injection dishes after bead injection, fertilization and bead targeting to the aster center (fig S9 a). Fixations were done under the microscope to ensure that eggs did not move or change shape during liquid exchange. Eggs were first fixed for 70 min 100 mM Hepes, pH 6.9, 50 mM EGTA, 10 mM MgSO4, 2% formaldehyde,0.2% glutaraldehyde, 0.2% Triton X-100, and 400 mM glucose. Eggs were then rinsed three times for 10 min in PBS plus Tween 20 (PBT) and one time in PBS and placed in 0.1% NaBH4 in PBS made fresh for 30 min. Eggs were rinsed again with PBS and PBT and blocked in PBT plus 5% goat serum and 0.1% BSA for 30 min. For MT staining, cells were incubated for 48 h with a primary anti–α-tubulin antibody, clone DM 1A (Sigma-Aldrich) at 1/8,000, rinsed twice in PBS, and then incubated for 4 h with fluorophore-conjugated anti-mouse secondary antibody (Sigma-Aldrich) at 1/750.