16-cell purple urchin embryo with EMTB-3G (microtubules) in shown cyan and mC-H2B (chromatin) in yellow. The embryo is treated with 15 µM trichostatin A (TSA), an inhibitor of HDAC6 (a tubulin deacetylase) that selectively disrupts dynamic microtubules in mammalian cells at time 00:00. Because of a slight asynchrony in mitosis at the time of TSA addition, each macromere exhibits a distinct phenotype. 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. The video corresponds to the second segment of video 5 and Fig. S3B in J Cell Biol. 2009 Dec 14;187(6):831-45. Note the control untreated video is the is also part of this image group.