Figure 4: PPP2R1A overexpression in oocytes causes meiotic maturation defects similar to CRL4^DCAF1 deletion.

(a,b) Western blot results showing levels of the indicated proteins in oocytes at GV, Pro-MI and MII stages, and in zygotes. The band intensities of the indicated proteins were quantified using Image-J software and are shown in (b). (c) Western blot results showing protein expression after injecting specific mRNAs. Total proteins from 100 injected oocytes were loaded in each lane. (d) PP2A-A overexpression in oocytes resulted in reduced GVBD and PBE rates. Numbers of injected oocytes for each mRNA are indicated (n). Error bars indicate s.e.m. ***P<0.001, Student’s t-test. (e) Images of oocytes injected with mRNA encoding for FLAG–GFP and FLAG–PPP2R1A at 4 and 14 h after release from GV arrest. Scale bar, 100 μm. Single representative oocytes are shown in the inserts. Green and red arrows indicate GV and PB1, respectively. (f) Western blot results showing degradation of securin in PPP2R1A overexpressing oocytes. Oocytes were cultured for the indicated times, and total proteins from 200 oocytes were loaded in each lane. (g) SMC3 immunofluorescence (red) on chromosomes of control and PPP2R1A overexpressing oocytes cultured for 14 h. Scale bar, 10μm. (h) Microscopic imaging of spindles and chromosomes of oocytes injected with the indicated mRNAs at 14 h after release from GV arrest. Scale bar, 10 μm.