The following chemicals were used: RO3306 (Axon MedChem), Okadaic Acid sodium salt (A.G. Scientifix), Thymidine and 2’-Deoxycytidine hydrate (Santa Cruz Biotechnology). The following antibodies were used; BUB1B (BubR1) (#4116), Cyclin B1 (#12231), Phospho-(Ser) CDK Substrate (#2324), pCdc2-Tyr15 (CDK1-Y15) (#9111), Plk1 (#4535), Aurora B (#3094) and Lamin A/C (#4777) (Cell Signaling Technologies), Securin (ab3306) (Abcam), Cyclin A (sc-596), Cdc2 (CDK1) (sc-137034), Mad2 (sc-47747), Cdc25C (sc-327) (Santa Cruz Biotechnology), centrin (#04–1624) (Millipore) and β-actin (A5441) (Sigma-Aldrich). Anti-Greatwall was obtained as previously described (Vigneron et al., 2009), and monoclonal β-Tubulin hybridoma antibody was a generous donation from Dr Natalie Morin (CRBM, France).