Figure 4.

Overexpression of hMad2–GFP inhibits homolog disjunction. (A) Wild-type oocytes or GV-stage oocytes microinjected with either hMad2–GFP mRNA or recombinant GFP were cultured in vitro and examined for PBE at 16 h post-GVBD. Intracellular concentrations of hMad2–GFP and GFP were estimated utilizing a calibration curve (see Supplementary Fig. 1A) and expressed as fold excess over endogenous mMad2. Oocyte numbers from four experiments are in parentheses. Asterisks denote statistically significant differences by Student's t-test when compared with wild-type or GFP-injected oocytes (p < 0.0001). (B,C) C-banded chromosome spreads performed at 16 h post-GVBD of oocytes microinjected at the GV-stage with either hMad2–GFP mRNA (B) or recombinant GFP (C). Intact bivalents possess darkly-staining centromeres at opposing ends (e.g., arrows in B) as opposed to a central location in monovalents (C). Original magnification, 1000×.