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Viral transport of DNA damage that mimics a stalled replication fork

Jaana Jurvansuu1, Kenneth Raj, Andrzej Stasiak

  • 1Swiss Institute for Experimental Cancer Research and National Center of Competence in Research Molecular Oncology, Epalinges, Lausanne, Switzerland.

Journal of Virology
|December 15, 2004
PubMed

Insights

Adeno-associated virus type 2 (AAV2) infection triggers cellular DNA damage responses. This study reveals AAV2 DNA activates ATR-Chk1 signaling, causing cell cycle arrest and offering insights into DNA replication stress.

Area of Science:

  • Molecular Biology
  • Virology
  • Cell Biology

Background:

  • Adeno-associated virus type 2 (AAV2) infection can cause cell cycle arrest or death, particularly if the p53 pathway is compromised.
  • AAV2 DNA, characterized by single strands and inverted terminal repeats, plays a crucial role in viral DNA replication and cell cycle regulation.

Purpose of the Study:

  • To investigate the DNA damage signaling pathways induced by AAV2 infection.
  • To elucidate the role of specific cellular proteins, such as ATR and Chk1, in the AAV2-mediated cellular response.
  • To explore the potential of AAV2 as a tool for studying cellular responses to aberrant DNA replication.

Main Methods:

  • Infection of human cells with AAV2, with and without UV treatment.
  • Analysis of DNA damage signaling pathways using techniques to detect protein interactions and localization (e.g., foci formation).
  • Assessment of cell cycle arrest (G2) and the roles of key signaling proteins like ATR, Chk1, TopBP1, and DNA polymerase delta.

Main Results:

  • AAV2 DNA triggers a DNA damage response similar to that of aberrant cellular DNA replication forks.
  • UV treatment of AAV2 enhances G2 arrest by creating persistent intrastrand DNA cross-links, maintaining viral DNA in a single-stranded form.
  • Nuclear foci formation and damage signaling involve DNA polymerase delta, ATR, TopBP1, RPA, and the Rad9/Rad1/Hus1 complex, but not ATM or NBS1.
  • ATR and Chk1 functions are essential for focus formation and damage signaling, leading to G2 arrest.
  • In human cells, AAV2 infection demonstrates that TopBP1 is required for Chk1 phosphorylation and subsequent DNA damage foci formation.

Conclusions:

  • AAV2 infection serves as a model system to study cellular responses to abnormal DNA replication without causing direct cellular DNA damage.
  • The ATR-Chk1 pathway, dependent on TopBP1, is critical for mediating the G2 arrest induced by AAV2.
  • This research provides novel insights into the interplay between viral DNA replication and host cell DNA damage response machinery.

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