A) Metaphase spindles in a normal cycle 10 wild-type ncdgfp* #4121 embryo. B–E) Metaphase-arrested spindles from hypoxic (B) wild-type ncdgfp* #4121, (C) ncdnk11gfp* M25M2, (D) ncdnk11gfp* M25M3#10 and (E) ncdNKgfp* M5M2 embryos. The arrested spindles of hypoxic wild-type ncdgfp* and ncdnk11gfp* embryos show reduced centrosomal fluorescence (arrowheads), a gap at the metaphase plate (arrows) corresponding to the chromosomes, and accumulation of motorGFP* at distal ends of astral microtubules (asterisks). These features are not observed in arrested spindles of hypoxic ncdNKgfp* embryos. Bars, 5 μm.