Phosphorylation of Mcm2 by Cdc7 promotes pre-replication complex assembly during cell-cycle re-entry.
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.
Chuang
Li-Chiou
LC
Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Teixeira
Leonardo K
LK
Wohlschlegel
James A
JA
Henze
Martha
M
Yates
John R
JR
Méndez
Juan
J
Reed
Steven I
SI
D000595:Amino Acid Sequence; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D002843:Chromatin / Q000378:metabolism; D019927:Cyclin E / Q000378:metabolism / Q000502:physiology; D051357:Cyclin-Dependent Kinase 2 / Q000378:metabolism / Q000502:physiology; D004261:DNA Replication; D006801:Humans; D064111:Minichromosome Maintenance Complex Component 2; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D016415:Sequence Alignment; D012694:Serine / Q000378:metabolism; D014158:Transcription, Genetic
C103706:CDC6 protein, human; D018797:Cell Cycle Proteins; D002843:Chromatin; D019927:Cyclin E; C485678:DBF4 protein, human; D009687:Nuclear Proteins; D012694:Serine; C068619:CDC7 protein, human; D017346:Protein Serine-Threonine Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; C084859:MCM2 protein, human; D064111:Minichromosome Maintenance Complex Component 2