Figure 5.

Reducing heterochromatin affects mitotic chromosome condensation and segregation. A) Squashed third-instar larval brains of indicated genotypes were stained with DAPI and photographed at the same magnification. Chromosome numbers are indicated. Arrowheads point to fused telomeres. Note that the metaphase chromosomes in hop^Tum-l/+, Su(var)205^+/−, and Stat92E^−/− (Stat92E^06346/F) brains are abnormally long, suggesting a lack of proper condensation. B) Embryos (0–2 h after egg deposition) of indicated maternal genotypes were fixed and immunostained with anti-pH3 (green) to reveal mitotic chromosomes and with anti-α-tubulin (red) to reveal mitotic spindles. Note the condensed metaphase chromosomes in wild-type embryos and lack of condensation in hop^Tum-l/+ and Stat92E^mat− embryos. Arrows indicate chromosomal bridges.