Cyclin B3 (CCNB3)

Cyclin B is a mitotic cyclin. The amount of cyclin B (which binds to Cdk1) and the activity of the cyclin B-Cdk complex rise through the cell cycle until mitosis, where they fall abruptly due to degradation. Cyclin B3 belongs to the highly conserved cyclin family, whose members are characterized by a dramatic periodicity in protein abundance through the cell cycle. Cyclins function as regulators of CDK kinases. Different cyclins exhibit distinct expression and degradation patterns which contribute to the temporal coordination of each mitotic event. Studies of similar genes in chick and Drosophila suggest that this cyclin may associate with CDC2 and CDK2 kinases, and be required for proper spindle reorganization and restoration of the interphase nucleus. Two transcript variants encoding different isoforms have been found for this gene.