Figure 4.

Essential role of cdc20 in meiosis I. a, Western blot of matured oocytes (50 per lane) following injection of cdc20^MO or cdc20 cRNA as indicated at the GV stage. The morpholino prevented re-accumulation of cdc20 during MI. The uncropped Western is displayed in the Supplementary Information, Fig S4. b, PB extrusion rates following maturation in oocytes injected with cdc20^MO, 5MM-cdc20^MO, cdc20 cRNA, or cdc20-GFP cRNA as stated. Cdc20 knockdown blocked completion of MI which was rescued by cdc20 cRNA. c, Cyclin B1-Venus degradation rate, plotted with respect to time as a percentage of the maximum recorded fluorescence, in oocytes injected with cdc20^MO (n=18); 5MM-cdc20^MO (n=15); or without further microinjection (n=15), pooled for each condition from at least 2 independent experiments. d, Cyclin B1-Venus degradation rate plotted as for (c), in cdh1 knockdown oocytes injected cdc20-CeFP cRNA (n=38) or no further injections (n=34), pooled for each condition from at least 2 independent experiments. The pipette concentration of cdc20-CeFP was high, four-fold that used in any other experiment. In (b), (c) and (d), asterisks imply significantly different from non-injected group, (p<0.05; b, ANOVA; c and d, t-test). In (c) and (d) the range over which PB extrusion occurred is as marked.