Fig. 6. mcph1 mutant embryos have reduced inhibitory phosphorylation of Cdk1, and normal Cyclin protein levels. Immunoblot analysis of wild-type embryos and mcph1^d2/d2 embryos 0-1 hour AED. Immunoblotted embryo extracts for Cyclin A, CyclinB, Cdk1 phospho-tyrosine 15 (p-Cdk1^tyr15), Cdk1, Chk1, and Actin as a loading control. mcph1^d2/d2 embryos have a reduced level of inhibitory Cdk1 phosphorylation compared to wild-type embryos, whereas other cell cycle proteins are apparently present at normal levels.