Nature Cell Biology
5, 1023 - 1025 (2003)
doi:10.1038/ncb1062
Homologue disjunction in mouse oocytes requires proteolysis of securin and cyclin B1Mary Herbert1, Mark Levasseur2, Hayden Homer1, Katie Yallop3, Alison Murdoch3
& Alex McDougall2, 41
Cell and Developmental Physiology Research Group, School of Surgical and Reproductive Sciences, Bioscience Centre, International Centre for Life, Times Square, Newcastle upon Tyne, NE1 4EP, UK. 2
Cell and Developmental Physiology Research Group, School of Cell and Molecular Bioscience, The Medical School, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK. 3
Newcastle Fertility Centre, Bioscience Centre, International Centre for Life, Times Square, Newcastle upon Tyne, NE1 4EP, UK. 4
Present address UMR 7009 CNRS, Université Pierre et Marie Curie (Paris VI), Observetoire Océanologique, 06230 Villefranche-sur-Mer, France.
Correspondence should be addressed to Mary Herbert Mary.Herbert@newcastle.ac.uk or Alex McDougall dougall@obs-vlfr.frDisjunction of pairs of homologous chromosomes during the first meiotic division (MI) requires anaphase-promoting complex (APC)-mediated activation of separase in budding yeast1,
2 and Caenorhabditis elegans
3,
4,
5, but not Xenopus laevis
6,
7. It is not clear which model best fits the mammalian system. Here we show that homologue disjunction in mouse oocytes is dependent on proteolysis of the separase inhibitor securin and the Cdk1 regulatory sub-unit cyclin B1. Proteolysis of both proteins was entirely dependent on their conserved destruction box (D-box) motifs, through which they are targeted to the APC8. These data indicate that the mechanisms regulating homologue disjunction in mammalian oocytes are similar to those of budding yeast and C.elegans.
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