Abstract
Cyclin E has been shown to have a role in pre-replication complex (Pre-RC) assembly in cells re-entering the cell cycle from quiescence. The assembly of the pre-RC, which involves the loading of six MCM subunits (Mcm2-7), is a prerequisite for DNA replication. We found that cyclin E, through activation of Cdk2, promotes Mcm2 loading onto chromatin. This function is mediated in part by promoting the accumulation of Cdc7 messenger RNA and protein, which then phosphorylates Mcm2. Consistent with this, a phosphomimetic mutant of Mcm2 can bypass the requirement for Cdc7 in terms of Mcm2 loading. Furthermore, ectopic expression of both Cdc6 and Cdc7 can rescue the MCM loading defect associated with expression of dominant-negative Cdk2. These results are consistent with a role for cyclin E-Cdk2 in promoting the accumulation of Cdc6 and Cdc7, which is required for Mcm2 loading when cells re-enter the cell cycle from quiescence.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Cell Cycle / physiology*
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Cell Cycle Proteins / chemistry
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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Cell Cycle Proteins / physiology*
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Chromatin / metabolism
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Cyclin E / metabolism
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Cyclin E / physiology
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Cyclin-Dependent Kinase 2 / metabolism
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Cyclin-Dependent Kinase 2 / physiology
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DNA Replication*
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Humans
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Minichromosome Maintenance Complex Component 2
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Molecular Sequence Data
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Nuclear Proteins / chemistry
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Phosphorylation
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Protein Serine-Threonine Kinases / physiology*
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Sequence Alignment
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Serine / metabolism
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Transcription, Genetic
Substances
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CDC6 protein, human
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Cell Cycle Proteins
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Chromatin
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Cyclin E
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DBF4 protein, human
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Nuclear Proteins
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Serine
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CDC7 protein, human
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Protein Serine-Threonine Kinases
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CDK2 protein, human
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Cyclin-Dependent Kinase 2
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MCM2 protein, human
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Minichromosome Maintenance Complex Component 2