FIGURE 1:

Accelerated passage through meiosis I in the absence of FZR1 is associated with earlier degradation of cyclin B1. (A) Polar body extrusion rates for fl/fl and Fzr1^−/− oocytes matured in vitro (n.s., p = 0.2; χ²). (B) Time between GVB and PBE for oocytes matured in vitro (**p = 0.004; t test) (C) Representative brightfield time-lapse images used to determine the GVB–PBE interval calculated in B. Arrows indicate the first appearance of PBE. (D) Cyclin B1-GFP degradation profile for fl/fl and Fzr1^−/− oocytes (n = 27 and 24, respectively). Arrows indicate mean time of polar body extrusion for microinjected oocytes; arrowheads indicate onset of cyclin B1 degradation. In A and B, parentheses give numbers of oocytes analyzed; error bars in B show SD. Scale bar in C, 20 μm.