Human cytomegalovirus prevents replication licensing by inhibiting MCM loading onto chromatin.
To allow DNA replication only once per cell cycle, origins of replication are reactivated ('licensed') during each G1 phase. Licensing is facilitated by assembly of the pre-replicative complex (pre-RC) at origins that concludes with loading the mini-chromosome maintenance (MCM) complex onto chromatin. Here we show that a virus exploits pre-RC assembly to selectively inhibit cellular DNA replication. Infection of quiescent primary fibroblasts with human cytomegalovirus (HCMV) induces all pre-RC factors. Although this is sufficient to assemble the MCM-loading factors onto chromatin, as it is in serum-stimulated cells, the virus inhibits loading of the MCM complex itself, thereby prematurely abrogating replication licensing. This provides a new level of control in pre-RC assembly and a mechanistic rationale for the unusual HCMV-induced G1 arrest that occurs despite the activation of the cyclin E-dependent transcription programme. Thus, this particularly large virus might thereby secure the supply with essential replication factors but omit competitive cellular DNA replication.
Wiebusch
Lüder
L
Department of Pediatrics, Laboratory for Molecular Biology, Charité, CCM-Ziegelstrasse, 5-9, Humboldt University, 10098 Berlin, Germany.
Uecker
Ralf
R
Hagemeier
Christian
C
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002417:Cattle; D018797:Cell Cycle Proteins / Q000378:metabolism; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism*; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D003587:Cytomegalovirus / Q000502:physiology*; D004261:DNA Replication / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005312:Fetal Blood / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism / Q000821:virology; D016193:G1 Phase; D015967:Gene Expression Regulation, Viral; D006801:Humans; D008168:Lung / Q000166:cytology / Q000196:embryology; D046911:Macromolecular Substances; D064111:Minichromosome Maintenance Complex Component 2; D064126:Minichromosome Maintenance Complex Component 3; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7; D009687:Nuclear Proteins / Q000378:metabolism; D051738:Origin Recognition Complex; D011485:Protein Binding; D029702:Schizosaccharomyces pombe Proteins; D014779:Virus Replication / Q000502:physiology*
C103706:CDC6 protein, human; C467199:CDT1 protein, human; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D016895:Culture Media, Serum-Free; D004268:DNA-Binding Proteins; C066470:MCM3 protein, human; D046911:Macromolecular Substances; D009687:Nuclear Proteins; C109152:ORC4 protein, human; D051738:Origin Recognition Complex; D029702:Schizosaccharomyces pombe Proteins; C085711:mcm5 protein, S pombe; C099243:MCM4 protein, human; C103258:MCM6 protein, human; C101624:MCM7 protein, human; D064111:Minichromosome Maintenance Complex Component 2; D064126:Minichromosome Maintenance Complex Component 3; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7