A mutation (dosach) in Drosophila which affects aster formation and nuclear migration during cleavage.

Here we describe a new mutant, dosach (dos), in Drosophila melanogaster. In the mutant, centrosomes divide and initiate spindle formation similar to that seen in wild-type embryos. Nevertheless, mutant embryos form cleavage spindles that lack visible asters and display abnormal morphology, including mono- and tri-polar spindles, spindle chains and incorrect alignment. Irregular nuclear migration is also observed in mutant embryos, and this may suggest that astral microtubules are important for spindle spacing during cleavage and also in maintaining the integrity of the mitotic apparatus. Confocal microscopy has been used to correlate organization of microtubules, centrosomal proteins and chromosomes in wild-type and dosach (dos) embryos.