title: Human cytomegalovirus prevents replication licensing by inhibiting MCM loading onto chromatin.
abstract: 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.
authors.affiliation: Department of Pediatrics, Laboratory for Molecular Biology, Charité, CCM-Ziegelstrasse, 5-9, Humboldt University, 10098 Berlin, Germany.
authors.forename: Lüder
authors.initials: L
authors.lastname: Wiebusch
authors.forename: Ralf
authors.initials: R
authors.lastname: Uecker
authors.forename: Christian
authors.initials: C
authors.lastname: Hagemeier
mesh_terms: 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*
chemical_list: 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