wing discs show some bi-nucleated cells, which are virtually absent in controls, and rare incidences of micronuclei, which suggest cytokinesis failure and chromosome fragmentation or mis-segregation. Mutant wing disc cells show a slight delay in mitotic progression (time from nuclear envelope breakdown to anaphase onset), chromosome mis-segregation wherein cells cease chromosome movement sooner than controls and segregate shorter distances, and shorter duration of the midbody; there are no significant defect in interzonal microtubule density in the first 2min after anaphase onset, but further into telophase interzonal microtubules focus into a single point instead of the expected two discrete bundles of microtubules on either side of the midbody; the interzonal microtubule regions is significantly diminished and microtubules disappear much faster than controls; the contractile ring is formed and there is complete membrane constriction down to the midbody.
Unlike controls, the larval brains (optic lobe and ventral nerve cord) of sip27
transheterozygotes and sip27
homozygotes show abnormal, large DNA masses that typically reside within single cells and are often surrounded by numerous micronuclei; most neuroblasts in sip27
homozygous larval brains show increased numbers of centrosomes and are polyploid, and some show synapsed chromosomes and asynchronous condensation.