Fig. 8

STE exposure inhibits RAF1 activity and induced oocyte asymmetric division defects. (A) Expression of RAF1 levels in control and STE-exposed oocytes. Proteins from 100 oocytes were loaded for each sample. (B) Relative-intensity results for RAF1 protein expression in the control and STE-treated oocytes. (C) Expression of ERK1/2 levels in control and STE-exposed oocytes. Proteins from 100 oocytes were loaded for each sample. (D) Expression of pERK1/2 levels in control and STE-exposed oocytes. Proteins from 100 oocytes were loaded for each sample. (E) Relative-intensity results for pERK1/2 protein expression in the control and STE-exposed oocytes. (F) Expression of RAF1 levels in control and RAF1-Inhibitor oocytes. Proteins from 100 oocytes were loaded for each sample. (G) Relative-intensity results for RAF1 protein expression in the control and RAF1-Inhibitor oocytes. (H) Representative images of oocytes from control and RAF1-Inhibitor groups. Red arrowheads denote oocytes with apparent symmetrical division and blue arrowheads indicate oocytes that fail to extrude polar bodies (scale bar, 80 μm). (I) The percentage of oocytes with large polar bodies after STE-treated. And the proportion of large polar body was (10.3 ± 1.86% [number of replicates = 3, number of oocytes = 105, and number of mice = 6], 19.0 ± 2.67% [number of replicates = 3, number of oocytes = 121, and number of mice = 6], p < 0.01) in control and RAF1 Inhibition groups. (J) Proposed model for the role of STE in oocyte maturation. STE exposure caused abnormal expression of GPX4 and ACSL4, which induced ferroptosis in oocytes. In addition, STE exposure inhibited RAF1 activity, which is one of the reasons for the defects in STE-induced asymmetric division in mice oocytes. Experiments were repeated three times, and the results are presented as mean ± SD (*significantly different at p < 0.05 and **significantly different at p < 0.01)