Figure 3.

Protein levels of cyclin B1 vs. cyclin B2 in meiosis I. According to 64, preceding resumption of meiosis, cyclin B2 (in red) is translated at higher levels than cyclin B1 (in blue) while their degradation rates are similar. Therefore, at GV stage, cyclin B2 protein is more abundant than cyclin B1. After entry into meiosis I, protein levels of cyclin B2 remain similar with only a slight increase in translation. However, cyclin B1 is actively translated leading to an increase of protein levels following GVBD reaching its maximum at metaphase I. Cyclin B1 translation depends on cyclin B2 protein at entry into meiosis I. Hence, protein levels of both cyclins are regulated differentially and temporally in mouse oocytes.