Expression profile of cyclin A2 in mouse oocytes. (a) Western blot analysis of cyclin A2 and securin levels in oocytes at different stages of meiosis: GV, GVBD, MI, and MII at 0, 2, and 8 h after release from arrest and superovulated oocytes, respectively (120 oocytes/lane). Data shown in a are representative of three replicate Western blots. Cyclin A2 increases at the MII stage, whereas securin is low. (b) Densitometric analysis of cyclin A2 levels. Data are mean and SEM from three individual experiments analyzed by t test. (c) Association of cyclin A2 (left) and securin (right) mRNA to polysomes at the GV, MI, and MII stages. Data are expressed as relative intensities. Data are mean and SEM from three individual experiments by t test. *, P < 0.05; **, P < 0.01.