Abstract
Cyclin E is necessary and rate limiting for the passage of mammalian cells through the G1 phase of the cell cycle. Control of cell cycle progression by cyclin E involves cdk2 kinase, which requires cyclin E for catalytic activity. Expression of cyclin E/cdk2 leads to an activation of cyclin A gene expression, as monitored by reporter gene constructs derived from the human cyclin A promoter. Promoter activation by cyclin E/cdk2 requires an E2F binding site in the cyclin A promoter. We show here that cyclin E/cdk2 kinase can directly bind to E2F/p107 complexes formed on the cyclin A promoter-derived E2F binding site, and this association is controlled by p27KIP1, most likely through direct protein-protein interaction. These observation suggest that cyclin E/cdk2 associates with E2F/p107 complexes in late G1 phase, once p27KIP1 has decreased below a critical threshold level. Since a kinase-negative mutant of cdk2 prevents promoter activation, it appears that transcriptional activation of the cyclin A gene requires an active cdk2 kinase tethered to its promoter region.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3T3 Cells
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Animals
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Binding Sites
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CDC2-CDC28 Kinases*
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Carrier Proteins*
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Cell Cycle Proteins*
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Cyclin-Dependent Kinase 2
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Cyclin-Dependent Kinase Inhibitor p27
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Cyclin-Dependent Kinases / antagonists & inhibitors
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Cyclin-Dependent Kinases / genetics
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Cyclin-Dependent Kinases / metabolism
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Cyclins / genetics*
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Cyclins / metabolism*
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DNA-Binding Proteins*
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E2F Transcription Factors
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Enzyme Inhibitors
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G1 Phase / physiology
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Humans
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Mice
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Microtubule-Associated Proteins / analysis
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Microtubule-Associated Proteins / physiology*
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Models, Genetic
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Promoter Regions, Genetic / genetics
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Protein Binding
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Protein Serine-Threonine Kinases / antagonists & inhibitors
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Recombinant Fusion Proteins
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Retinoblastoma-Binding Protein 1
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Retinoblastoma-Like Protein p107
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Transcription Factor DP1
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Transcription Factors / metabolism
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Transcriptional Activation / physiology*
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Transfection
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Tumor Suppressor Proteins*
Substances
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Arid4a protein, mouse
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Carrier Proteins
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Cdkn1b protein, mouse
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Cell Cycle Proteins
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Cyclins
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DNA-Binding Proteins
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E2F Transcription Factors
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Enzyme Inhibitors
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Microtubule-Associated Proteins
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Nuclear Proteins
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RBL1 protein, human
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Rbl1 protein, mouse
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Recombinant Fusion Proteins
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Retinoblastoma-Binding Protein 1
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Retinoblastoma-Like Protein p107
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Transcription Factor DP1
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Transcription Factors
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Tumor Suppressor Proteins
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Cyclin-Dependent Kinase Inhibitor p27
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Protein Serine-Threonine Kinases
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CDC2-CDC28 Kinases
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CDK2 protein, human
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Cdk2 protein, mouse
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Cyclin-Dependent Kinase 2
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Cyclin-Dependent Kinases