Fig. 5.

MI spindle formation and activation of Ccnb1 and Mos translation are disrupted in Ccnb2^−/− mice. (A,B) Oocytes were injected with a 1:1 mix of polyadenylated mCherry and either YFP-Ccnb1-long 3′UTR (A) or YFP-Mos 3′UTR (B). After overnight incubation, oocytes were released in cilostamide-free medium, and brightfield, YFP and mCherry images were acquired every 15 min for 24 h. YFP signals were normalized by maximal mCherry signals (YFP/mCherry). The normalized rate of YFP accumulation was calculated for each oocyte before (0-2 h) and after (4-6 h) GVBD. Rates were plotted as the median (red) and interquartile range. Student's t-tests were used to evaluate statistical significance; **P=0.0058, ****P<0.0001. The number of oocytes from three independent experiments is reported for each condition. (C) Oocytes were released in cilostamide-free medium and fixed for 8 h after meiotic resumption. The spindle, chromatin and kinetochores were visualized with β-tubulin 488 antibody, DAPI and CREST, respectively. Images show oocytes arrested in prophase I, GVBD without a spindle, early spindle (tubulin organized into a sphere surrounded by chromosomes) and bipolar MI spindle. Scale bars: 10 µm. (D) Oocytes were scored for maturation stage and data are presented as the percentage of total oocytes. The number of oocytes from two independent experiments observed for each group is reported.