Confocal images of unicellular NT embryos immunolabeled with the anti-a-tubulin antibody (green) and DNA stained with propidium iodide (red). (A) Before the second set of electrostimulation, a misaligned metaphase plate was associated with the spindle, and sometimes individual chromosomes (arrows in the insert) were localized near the spindle poles (insert: 3-fold magnified view of the spindle region). (B) Upon removal of CHX and 6-DMAP, 72% of NT embryos (n = 25) showed a small nucleus and an interphasic microtubular network (arrow). (C) One hour after removal of the drugs, all NT embryos were in interphase and 71% (n = 17) exhibited a single and large pronucleus-like nucleus like those observed in normal rabbit zygotes (not shown). Bar, 50 mm.