Fig. 2.

Protrusion requires Cdk1 inactivation but not proteolysis. a–e Flavopiridol-induced Cdk1 inactivation accelerates anaphase and protrusion-onset. Oocytes were untreated (a; see Supplementary Movie 7) or treated with DMSO (b; see Supplementary Movie 8) or flavopiridol (c; see Supplementary Movie 9) from 6 h post-GVBD. Quantification of time of anaphase-onset (d) and protrusion-onset (e). Two-tailed Student’s t test (d) or one-way ANOVA (e) used for statistical analysis. P values represented as ***P < 0.001 and ****P < 0.0001, ns denoted P > 0.05. Box plots depict median (horizontal line), mean (crosses), 25th and 75th percentiles (boxes) and 5th and 95th percentiles (whiskers). f–h Flavopiridol induces protrusion despite lack of proteolysis. Oocytes were treated either with flavopiridol prior to proteolysis onset (see Supplementary Figure 6) (f; see Supplementary Movie 10) or with the APC-inhibitor, APCIN, followed by flavopiridol (g; see Supplementary Movie 11) or the 26S proteasome inhibitor, MG132, followed by flavopiridol (h; see Supplementary Movie 12). Anaphase failure reflects lack of proteolysis resulting in chromosome entrapment within the furrow. Times in panels are hours:minutes post-GVBD. Scale bars, 10 µm. White arrowheads indicate protrusion-onset. Oocyte numbers are shown in parentheses from a minimum of three independent experiments