Eight-cell purple urchin embryo expressing three tandem GFPs fused to the ensconsin microtubule-binding domain (EMTB-3G; Faire et al., 1999). The embryo was treated with 20 µM nocodazole at time 00:00. Purple urchin embryos were imaged with a laser scanning confocal microscope (Radiance 2000; Bio-Rad Laboratories) mounted on a compound microscope (E800; Nikon) using a 40× 1.3 NA Plan-Fluor oil lens. Room temperature was maintained at 14â€“17°C, which is tolerated well. Movie corresponds to second segment of Video 3 in J Cell Biol. 2009 Dec 14;187(6):831-45.