OVEREXPRESSION OF CYCLIN-E AND CYCLIN-DEPENDENT KINASE INHIBITOR (P27(KIP1)) - EFFECT ON CELL-CYCLE REGULATION IN HELA-CELLS

Transfection of the epithelioid cell line HeLa with p27(Kip1) resulted in an accumulation of cells in the G(1) phase of the cell cycle. Alth ough the cellular level of cdk2 was not decreased as a result of this transfection, there was a significant decline in the cdk2 associated k inase activity. Restoration of the cdk2 kinase activity was proportion al to the amount of cotransfected cyclin E plasmid DNA. Overexpression of cyclin E also reversed the p27(Kip1) mediated G(1) growth arrest. These findings suggest that the overexpression of cyclin E reverses th e p27(Kip1) mediated G(1) growth arrest by binding the inhibitor resto ring the cdk2 associated kinase activity necessary for the G(1)/S tran sition. (C) 1997 Academic Press.