Fig. 7.

FBXO28 Is A Key F-box Protein for SCF Activity.A, schematic diagram showing the structure of SCF complex. F-BOX proteins detected in proteome are shown in the right panel. B, volcano plot showing the relative abundance of F-BOX proteins between GV oocytes and MII oocytes. Differential F-BOX proteins (fold change >2) are indicated by red dots. C, relative FBXO28 protein level in oocytes. D, schematic presentation of the experimental design to investigate the role of FBXO28 during oocyte maturation. E, knockdown efficiency of Fbxo28 siRNA. F, percentage of four meiotic stages (GV, GVBD, MI, and MII) in oocytes injected with control siRNA and siFbxo28. G, Venn diagram showing the exclusive or shared upregulated proteins in oocytes of MLN4924 treated group (set I) and FBXO28-knockdown group (set II). H, heatmap showing the 69 common proteins upregulated in both the control group and the FBXO28-depletion group. I, top 10 upregulated proteins in oocytes with FBXO28 depletion. J, UBAP1 protein expression in control and FBXO28-depletion oocytes. K, immunoblotting results show the overexpression (OE) of exogenous UBAP1 protein in oocytes. L, bright-field images of control and UBAP1-OE oocytes. Arrowheads point to oocytes that fail to extrude a polar body. The scale bar represents 100 μm. M, quantitative analysis of Pb1 extrusion rate in control and UBAP1-OE oocytes. N, Pb1 extrusion rates of control, FBXO28-depletion, and FBXO28/UBAP1 double depletion oocytes. Data are expressed as the mean ± SD from three independent experiments in which at least 100 oocytes were analyzed for each group. For statistical analysis, a two-tailed Student’s t test was used in all panels, compared with GV or control. ∗∗∗p < 0.001.