FIGURE 5.

ASB7 overexpression alleviates maternal age-induced oocyte meiotic defects. (A) Representative Western blot showing the ASB7 expression in oocytes from young and old mice (100 oocytes per lane). (B) Schematic illustration of the experimental procedure for overexpression. (C) Representative Western blot result shows the efficiently overexpressed exogenous ASB7 protein. (D) Young, old, old + PBS, and old + ASB7 oocytes were stained with α-tubulin antibody to visualize spindle (green) and counterstained with PI to visualize chromosome (red). Yellow arrowheads direct to the disorganized spindles and white arrows indicate the misaligned chromosomes. Scale bar: 30 μm. (E) Quantification of young (n = 103), old (n = 112), old + PBS (n = 115), and old + ASB7 (n = 104) oocytes with spindle/chromosome defects. (F) Chromosome spread of young, old, old + PBS, and old + ASB7 MII oocytes. Chromosomes were stained with Hoechst 33342 (blue), and kinetochores were labeled with CREST (purple). Scale bar: 10 μm. (G) Quantification of aneuploidy in young (n = 35), old (n = 38), old + PBS (n = 34), and old + ASB7 (n = 32) oocytes. Data are expressed as mean percentage ± SEM of three independent experiments. *p < 0.05 vs controls.