Fig. 5. Synthetic phenotypes in embryos simultaneously compromised for ZYG-9-TAC-1 and ZYG-8. (A-D) Images from time-lapse DIC microscopy sequences of wild-type (A), tac-1(RNAi) (B), zyg-8(or484) (C) and zyg-8(or484) tac-1(RNAi) (D) embryos; Row 1, pseudocleavage stage (interphase); row 2, metaphase; row 3, end of anaphase; row 4, cytokinesis; row 5, merged immunostainings of -tubulin (green), SPD-5 (red) and DNA (blue), documenting the state of microtubules and centrosomes in anaphase one-cell stage embryos of these genotypes. Arrows point to female pronuclei, arrowheads to spindle poles. Elapsed time is indicated in minutes and seconds. Embryos are 50 µm long. See Table 2 for quantifications. Note that the spindle is less elongated and less distant from the posterior cortex in zyg-8(or484) tac-1(RNAi) embryos (D) than in tac-1(RNAi) embryos (B). Note also that the cleavage furrow does not ingress to bisect the spindle in zyg-8(or484) tac-1(RNAi). However, furrowing activity does take place towards the embryo anterior, orthogonal to the A-P axis, like in embryos lacking microtubules (e.g. Gönczy et al., 2001). Notice the numerous small asters present in the cytoplasm of zyg-8(or484) tac-1(RNAi) embryos, which might result from a larger pool of free cytoplasmic tubulin possibly promoting non-centrosomal microtubule nucleation. Anterior is left, posterior is right; bar, 10 µm.