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Preventing re‐replication in eukaryotes
Author(s) -
Li Joachim,
Morreale Richard M
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a511-d
Subject(s) - licensing factor , origin recognition complex , pre replication complex , dna re replication , control of chromosome duplication , biology , origin of replication , dna replication , s phase , dna replication factor cdt1 , minichromosome maintenance , replication factor c , eukaryotic dna replication , replication (statistics) , replication timing , genetics , microbiology and biotechnology , computational biology , gene , virology
We are interested in understanding the regulatory mechanisms that prevent re‐replication within a single eukaryotic cell cycle and the consequences of disrupting these mechanisms on genomic stability. We have previously shown in Saccharomyces cerevisiae that cyclin dependent kinases (CDKs) prevent re‐replication by phosphorylating and down regulating three components of the pre‐replicative complex (pre‐RC), Mcm2‐7, Cdc6 and ORC; simultaneous disruption of these mechanisms is needed to detect significant, but incomplete, re‐replication in G2/M phase. To better understand how this deregulation leads to re‐replication and why it is incomplete, we have performed a genome‐wide analysis of this re‐replication using microarray comparative genomic hybridization (CGH). We observe that re‐replication is limited to specific regions of the genome for two reasons: (1) re‐initiation only occurs at a subset of the origins that are available for S phase initiation and (2) elongation is restrained during re‐replication. These data show that there are additional mechanisms blocking re‐replication and that origins differ in their susceptibility to re‐replication. We also show that deregulation of Mcm2‐7, Cdc6, and ORC during S phase leads to greater re‐replication than in G2/M phase, indicating that the capacity to block re‐replication is dynamic. Finally, the microarray CGH assay reveals that deregulation of fewer initiation proteins still leads to re‐replication, albeit at levels undetectable by standard replication assays. This finding indicates that the mechanisms preventing re‐replication are not strictly redundant and suggest that re‐replication may occur more frequently and be a greater source of genomic instability than previously appreciated.