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Differential activation of cellular DNA damage responses by replication-defective and replication-competent

Anand Prakash1, Sumithra Jayaram, Eileen Bridge

  • 1Department of Microbiology, Miami University, Oxford, Ohio, USA.

Journal of Virology
|September 28, 2012
PubMed

Insights

Adenovirus E4 mutants activate DNA damage responses. Viral DNA replication is crucial for phosphorylating Nbs1, a key DNA repair protein, indicating its role in triggering cellular repair pathways.

Area of Science:

  • Virology
  • Molecular Biology
  • Cellular Biology

Background:

  • Adenovirus (Ad) infection triggers cellular DNA damage responses.
  • Early region 4 (E4) and E1b proteins in wild-type Ad type 5 (Ad5) interfere with the DNA repair protein Mre11.
  • The specific characteristics of Ad infection that activate cellular DNA repair remain unclear.

Purpose of the Study:

  • To investigate the activation of DNA damage responses by a replication-defective Ad vector lacking E1 and E1a proteins (AdRSVβgal).
  • To determine the role of viral early gene expression and DNA replication in activating cellular DNA repair pathways.

Main Methods:

  • Infection of cells with a replication-defective Ad vector (AdRSVβgal).
  • Analysis of DNA damage response protein activation, including Mdc1, Nbs1, and Chk1.
  • Assessment of viral early gene expression and DNA replication.

Main Results:

  • AdRSVβgal infection induced the formation of Mdc1 protein foci.
  • AdRSVβgal infection failed to activate Nbs1 and Chk1 phosphorylation.
  • Viral DNA replication was identified as important for Nbs1 phosphorylation.

Conclusions:

  • Early Ad gene expression, particularly E1a, is not solely responsible for activating all DNA damage responses.
  • Viral DNA replication acts as a significant trigger for the phosphorylation of specific DNA repair proteins like Nbs1.
  • Understanding these mechanisms is crucial for developing effective Ad-based vectors and antiviral strategies.

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