Fig. 7. Nuclear loss, spindle morphology and spindle orientation. (A-C,H-J) Syncytial embryos in nuclear cycle 13 (A-C) and dividing ectoderm in germband-extended embryos (H-J); actin, red; microtubules, green; DNA, blue; lower rows show microtubules alone. (A-C) APC2^g10 APC1^Q8 syncytial embryos (B,C) do not have significant defects in spindle morphology. Note weak actin rings (arrow, B) and nuclear loss evidenced by empty actin rings (arrow, C). (D,E) Syncytial wild type (D) and APC2^g10 (E). DNA is stained with DAPI. Arrowheads indicate out-of-focus yolk nuclei; arrows indicate nuclei lost from surface. (F) Quantification of nuclear loss in APC2 and APC2 APC1 mutant syncytial embryos. Bars show the percentage embryos with 2% of cortical nuclei lost (see Materials and methods). APC2^c9, purple; APC2^N175K, yellow; APC2^S, red; APC2^d40, green; APC2^g10, blue. (G) Quantification of syncytial spindle length (pole-to-pole). (H-J) Wild-type spindles are parallel to the epithelium (arrowheads, H) and divisions are symmetric (arrow, H). Spindle orientation (arrowheads, I,J) and division plane (arrows, I,J) are normal in APC2^g10 APC1^Q8 M/Z mutants (J) and embryos maternally APC2^d40 and zygotically APC2^d40/+ (I). (K) Quantification of these phenotypes. Scale bars: 10 µm.