Aberrant Cell Cycle Progression and Endoreplication in Regenerating Livers of Mice That Lack a Single E-Type Cyclin

CcnE2 has an unexpected role in repressing CcnE1; the phenotype of E2−/− mice appears to result from CcnE1 overexpression and cdk2 hyperactivation. CcnE1 and CcnE2 therefore have nonredundant functions for S-phase entry and endoreplication during liver regeneration.