... divisions. Nuclei in BubR1 mutant embryos do not arrest in response to spindle damage suggesting that BubR1 performs a checkpoint function during syncytial divisions. Furthermore, we find that in wild-type embryos BubR1 localises to the kinetochores of condensed polar body chromosomes. This localisation...

... around the egg cortex in a microfilamentdependent process. Each cluster has the capacity, on removal from nocodazole, to organize a spindle that rotates to yield a polar body. In this process of spindle formation, the chromosome clusters are able both to promote tubulin polymerization in their vicinity...