16-cell purple urchin embryo expressing three tandem GFPs fused to the ensconsin microtubule-binding domain (EMTB-3G; Faire et al., 1999). 10 µM nocodazole was added at time 00:00. The top left cell entered anaphase around time 0; none of the other cells in view left metaphase nor furrowed. This one cell cleaved despite nearly complete absence of astral microtubules, and the furrow crossed the spindle midzone 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 14–17°C, which is tolerated well. Corresponds to Fig 3B and third segment of Video 3 in J Cell Biol. 2009 Dec 14;187(6):831-45.