Regulation of cyclin E and p27kip during mitosis in BALB/c 3T3 cells.
We have examined the level of cyclin E, a G1 cyclin, and p27kip, a cyclin-dependent kinase inhibitor, in BALB/c 3T3 cells. Cell populations stimulated to undergo cell cycle traverse displayed little change in the level of cyclin E, while p27kip was found to be reduced 50-80% in proliferating cells. Analysis of mitotic cells, however, revealed that cyclin E is virtually absent and begins to reaccumulate soon after mitosis is complete, as does p27kip. Immunoprecipitation experiments revealed that p27kip is associated with cyclin E in quiescent but not proliferating cells, indicating that it may function to prevent development of cyclin E activity in the absence of growth factors. Based on our characterization of cyclin E and p27kip in BALB/c 3T3 cells during progression of the cell cycle, we propose a model of growth regulation controlling the G1 phase of growing and quiescent cells involving mitotic degradation of cyclin E and recovery of p27kip inhibitory activity in a late or postmitotic interval.
Agrawal
D
D
H. Lee Moffitt Cancer Center and Research Institute, University of South Florida College of Medicine, Tampa 33612, USA.
Dong
F
F
Wang
Y Z
YZ
Kayda
D
D
Pledger
W J
WJ
D016475:3T3 Cells; D000818:Animals; D018797:Cell Cycle Proteins; D002455:Cell Division; D050760:Cyclin-Dependent Kinase Inhibitor p27; D016213:Cyclins / Q000096:biosynthesis*; D016193:G1 Phase; D051379:Mice; D008807:Mice, Inbred BALB C; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis*; D008938:Mitosis; D015739:Nocodazole / Q000494:pharmacology; D047428:Protein Kinase Inhibitors; D025521:Tumor Suppressor Proteins
C493961:Cdkn1b protein, mouse; D018797:Cell Cycle Proteins; D016213:Cyclins; D008869:Microtubule-Associated Proteins; D047428:Protein Kinase Inhibitors; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D015739:Nocodazole