An E2F1-mediated DNA damage response contributes to the replication of human cytomegalovirus

PLoS Pathog. 2011 May;7(5):e1001342. doi: 10.1371/journal.ppat.1001342. Epub 2011 May 12.


DNA damage resulting from intrinsic or extrinsic sources activates DNA damage responses (DDRs) centered on protein kinase signaling cascades. The usual consequences of inducing DDRs include the activation of cell cycle checkpoints together with repair of the damaged DNA or induction of apoptosis. Many DNA viruses elicit host DDRs during infection and some viruses require the DDR for efficient replication. However, the mechanism by which DDRs are activated by viral infection is poorly understood. Human cytomegalovirus (HCMV) infection induces a DDR centered on the activation of ataxia telangiectasia mutated (ATM) protein kinase. Here we show that HCMV replication is compromised in cells with inactivated or depleted ATM and that ATM is essential for the host DDR early during infection. Likewise, a downstream target of ATM phosphorylation, H2AX, also contributes to viral replication. The ATM-dependent DDR is detected as discrete, nuclear γH2AX foci early in infection and can be activated by IE proteins. By 24 hpi, γH2AX is observed primarily in HCMV DNA replication compartments. We identified a role for the E2F1 transcription factor in mediating this DDR and viral replication. E2F1, but not E2F2 or E2F3, promotes the accumulation of γH2AX during HCMV infection or IE protein expression. Moreover, E2F1 expression, but not the expression of E2F2 or E2F3, is required for efficient HCMV replication. These results reveal a novel role for E2F1 in mediating an ATM-dependent DDR that contributes to viral replication. Given that E2F activity is often deregulated by infection with DNA viruses, these observations raise the possibility that an E2F1-mediated mechanism of DDR activation may be conserved among DNA viruses.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Ataxia Telangiectasia Mutated Proteins
  • Caffeine / pharmacology
  • Cell Cycle Proteins / genetics*
  • Cell Cycle Proteins / metabolism
  • Cell Line
  • Cytomegalovirus / genetics
  • Cytomegalovirus / growth & development
  • Cytomegalovirus / physiology*
  • Cytomegalovirus Infections / virology*
  • DNA Damage*
  • DNA Repair / physiology
  • DNA, Viral / biosynthesis
  • DNA, Viral / genetics
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism
  • E2F1 Transcription Factor / genetics
  • E2F1 Transcription Factor / metabolism*
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Fibroblasts / virology
  • Fluorescent Antibody Technique
  • Histones / metabolism
  • Humans
  • Immediate-Early Proteins / metabolism
  • Immunoblotting
  • Phosphodiesterase Inhibitors / pharmacology
  • Protein Serine-Threonine Kinases / genetics*
  • Protein Serine-Threonine Kinases / metabolism
  • RNA, Small Interfering / metabolism
  • Signal Transduction
  • Trans-Activators / metabolism
  • Tumor Suppressor Proteins / genetics*
  • Tumor Suppressor Proteins / metabolism
  • Virus Replication / physiology*


  • Cell Cycle Proteins
  • DNA, Viral
  • DNA-Binding Proteins
  • E2F1 Transcription Factor
  • E2F1 protein, human
  • H2AX protein, human
  • Histones
  • IE1 protein, cytomegalovirus
  • IE2 protein, Cytomegalovirus
  • Immediate-Early Proteins
  • Phosphodiesterase Inhibitors
  • RNA, Small Interfering
  • Trans-Activators
  • Tumor Suppressor Proteins
  • Caffeine
  • ATM protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • Protein Serine-Threonine Kinases