Figure 5: Oocyte-specific Ppp2r1a knockout rescues the meiotic defects caused by DDB1 deletion.

(a) Ovulated oocytes from Ddb1/Ppp2r1a^oo−/− females compared with WT and Ddb1^oo−/− oocytes in Fig. 1c. PBE is indicated (75.4%). Red arrows indicate PB1. Scale bar, 200 μm. (b) Confocal microscopic images of ovulated Ddb1/Ppp2r1a^oo−/− oocytes compared with WT and Ddb1^oo−/− oocytes in Fig. 1e. Oocyte outlines are highlighted by broken lines. Arrows indicate misaligned chromosomes. Scale bar, 10 μm. (c) In vitro GVBD and PBE rates of GV oocytes collected from mice with the indicated genotypes. PBE was analysed only for oocytes that underwent GVBD within 4 h. Error bars indicate s.e.m. and the numbers of analysed oocytes are indicated. ***P<0.001, Student’s t-test. (d) Confocal microscopic images of WT, Ddb1^oo−/− and Ddb1/Ppp2r1a^oo−/− oocytes after in vitro culture for 14 h. Scale bar, 10 μm. (e) Morphologies of oocytes from mice with the indicated genotypes after in vitro culture for 14 h. Single representative oocytes are shown in the inserts. Red arrows indicate PB1.Scale bar, 100 μm. (f) Representative chromosome configurations of the indicated genotypes. GV oocytes were cultured for 14 h and then used to prepare chromosome spreads. Precociously segregated sister chromatids are indicated by arrows. Enlarged chromosomes are shown in the inserts. Scale bar, 5 μm. (g) Schematic showing CRL4^DCAF1 function for regulating PP2A-A degradation to facilitate oocyte meiotic progression.