nucleus | embryonic stage (with Df(3R)Exel6162)
aurA1/Df(3R)Exel6162 embryos exhibit severe chromosome mis-segregation defects.
Embryos from homozygous mothers show prometaphase nuclei in juxtaposition to paired sets of centrosomes. The paired centrosomes function together as a single pole to nucleate bipolar spindles associated with two groups of condensed chromosomes. Other embryos show more extremely mitotic defects in which spindle structures associated with discrete groups of condensed chromosomes become intricately branched, sharing common centrosomes as microtubule-organizing centers. Free centrosomes that have dissociated from spindles can also be seen in such embryos. Later embryos have many polyploid nuclei. Real time observation reveals example of chromatids being pulled towards the pole of the neighboring spindle, and incomplete anaphase ending with a tetraploid nucleus.
Embryos abnormal from nuclear cycle 9 onward; multiple spindles assemble in long arrays with shared centrosomes; polyploid nuclei develop with multiple centrosomes. Hemizygotes pupate but form longer-than-normal pupae.