Differential cell cycle arrest and apoptosis following inducffile expression of the cyclbst dependent kinase inhibitor p21 CIP1 in human cells

Abstract

The p21 Cip1/Waf1 Cyclin dependent kinase inhibitor has been implicated in G1 arrest following irradiation,as well as in maintaining terminally arrested,differentiated cells in G0/G1.The G1 arrest is mediated by inhibiting the Cdk dependent phosphorylation of the retinoblastoma protein,Rb.We sought to understand better these effects,and additionally what effects p21 might have in S phase and G2/M,by expressing p21 in a panel of human cell lines using a tetracycline controlled inducible system.as well as using an adenoviral transduction vector. Our results concerning our observations of differential cell cycle arrest,apoptosis,and the underlying biochemical mechanisms of these effects will be..