Cyclin-dependent kinases prevent DNA re-replication through multiple mechanisms.
The stable propagation of genetic information requires that the entire genome of an organism be faithfully replicated once and only once each cell cycle. In eukaryotes, this replication is initiated at hundreds to thousands of replication origins distributed over the genome, each of which must be prohibited from re-initiating DNA replication within every cell cycle. How cells prevent re-initiation has been a long-standing question in cell biology. In several eukaryotes, cyclin-dependent kinases (CDKs) have been implicated in promoting the block to re-initiation, but exactly how they perform this function is unclear. Here we show that B-type CDKs in Saccharomyces cerevisiae prevent re-initiation through multiple overlapping mechanisms, including phosphorylation of the origin recognition complex (ORC), downregulation of Cdc6 activity, and nuclear exclusion of the Mcm2-7 complex. Only when all three inhibitory pathways are disrupted do origins re-initiate DNA replication in G2/M cells. These studies show that each of these three independent mechanisms of regulation is functionally important.
Nguyen
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VQ
Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0414, USA.
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D017489:CDC28 Protein Kinase, S cerevisiae / Q000378:metabolism*; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone; D004261:DNA Replication; D004271:DNA, Fungal / Q000096:biosynthesis* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D064168:Minichromosome Maintenance Complex Component 7; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D051738:Origin Recognition Complex; D010766:Phosphorylation; D018741:Replication Origin; D012097:Repressor Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D051738:Origin Recognition Complex; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D017489:CDC28 Protein Kinase, S cerevisiae; C069199:MCM2 protein, S cerevisiae; C491088:MCM7 protein, S cerevisiae; D064168:Minichromosome Maintenance Complex Component 7