Bub3 gene disruption in mice reveals essential mitotic spindle checkpoint function during early embryogenesis
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Updated: Oct 13, 2026

Evaluation of the Spindle Assembly Checkpoint Integrity in Mouse Oocytes
Published on: September 13, 2022
P Kalitsis1, E Earle, K J Fowler
1Murdoch Children's Research Institute, Royal Children's Hospital, Flemington Road, Parkville 3052, Melbourne, Australia.
Abstract:
Bub3 is a conserved component of the mitotic spindle assembly complex. The protein is essential for early development in Bub3 gene-disrupted mice, evident from their failure to survive beyond day 6.5-7.5 postcoitus (pc). Bub3 null embryos appear normal up to day 3.5 pc but accumulate mitotic errors from days 4.5-6.5 pc in the form of micronuclei, chromatin bridging, lagging chromosomes, and irregular nuclear morphology. Null embryos treated with a spindle-depolymerising agent fail to arrest in metaphase and show an increase in mitotic disarray. The results confirm Bub3 as a component of the essential spindle checkpoint pathway that operates during early embryogenesis.
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