Interaction between XGef and CPEB is necessary for the influence of XGef overexpression on oocyte maturation. (A) Effect of HA-XGef, HA-Globin, HA-XGef(65–360), and HA-XGef(Δ65–234) overexpression on progesterone-induced oocyte maturation, monitored by appearance of GVBD. Inset, anti-HA antibody immunoblot analysis of HA-XGef, HA-Globin, HA-XGef(65–360), and XGef(Δ65–234) levels in oocytes. (B) Histogram of the percentage of GVBD in oocytes overexpressing HA-XGef or HA-XGef(65–360) when Globin-overexpressing oocytes within the same experiment had reached 50% GVBD. Results from 10 independent experiments with at least 30 oocytes per injection were statistically analyzed using the Student's t test. *P < 0.01.