Fig. 6. Intact DNA-replication checkpoint and normal Cyclin B levels in mcph1 embryos. (A) Quantification of cell-cycle timing during cortical divisions of early embryogenesis. No significant differences in interphase (I) or mitosis (M) lengths were observed for mnk mcph1^Z1861 embryos compared to wild-type or mnk controls, whereas shorter interphases were apparent in mei-41 embryos (cycles 12 and 13). Average times with standard deviations (error bars) are shown. Numbers of embryos scored for each genotype are shown in parentheses. (B) Western analysis using phospho-specific antibodies against Cdk1 reveals wild-type levels of pY15-Cdk1 in extracts of mnk mcph1^Z1861 embryos (1-2 hours). Control grp embryos have reduced pY15-Cdk1 levels. (C) Western analysis reveals normal Cyclin B levels in mnk mcph1^Z1861 embryos (1-2 hours). (D) Western analysis reveals normal GRP levels in mcph1 and mnk mcph1^Z1861 embryos (1-2 hours unless otherwise indicated). Loading controls: anti--tubulin or anti-GAPDH.