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Human cytomegalovirus inhibits a DNA damage response by mislocalizing checkpoint proteins

Miguel Gaspar1, Thomas Shenk

  • 1Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, USA.

Proceedings of the National Academy of Sciences of the United States of America
|February 16, 2006
PubMed

Insights

Human cytomegalovirus (CMV) DNA replication activates the DNA damage checkpoint but blocks its signaling. Checkpoint proteins are mislocalized to the cytoplasm, inhibiting DNA repair and promoting virus replication.

Area of Science:

  • Molecular Biology
  • Virology
  • Cell Biology

Background:

  • DNA damage checkpoint pathways are crucial for genomic stability.
  • Viruses often interact with host cell machinery, including DNA damage responses.
  • Human cytomegalovirus (CMV) is a significant human pathogen with complex interactions with host cells.

Purpose of the Study:

  • To investigate the effect of human CMV DNA replication on the DNA damage checkpoint pathway.
  • To determine how CMV modulates the ataxia-telangiectasia mutated (ATM) and checkpoint kinase 2 (Chk2) signaling pathway.
  • To elucidate the mechanism by which CMV evades DNA damage responses.

Main Methods:

  • Activation of the ATM/Chk2 pathway in response to CMV DNA replication.
  • Analysis of checkpoint protein localization during CMV infection using immunofluorescence.
  • Immunoprecipitation assays to confirm protein-protein interactions.
  • Assessment of virus replication resistance to ionizing radiation.

Main Results:

  • CMV DNA replication activates the ATM pathway but blocks signaling at Chk2.
  • Checkpoint proteins ATM and Chk2 are mislocalized to a cytoplasmic viral assembly site late in infection.
  • Mislocalized checkpoint proteins colocalize with CMV virion structural proteins.
  • CMV replication is resistant to ionizing radiation-induced DNA double-strand breaks.

Conclusions:

  • Human CMV DNA replication triggers the DNA double-strand break response.
  • CMV actively inhibits the DNA damage checkpoint by mislocalizing key proteins (ATM, Chk2) to the cytoplasm.
  • This viral strategy allows for evasion of DNA repair mechanisms and promotes efficient viral replication.

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