• Register
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.


Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.


The EBNA-3 gene family proteins disrupt the G2/M checkpoint.

The Epstein-Barr nuclear antigens (EBNA), EBNA-3, -4 and -6, have previously been shown to act as transcriptional regulators, however, this study identifies another function for these proteins, disruption of the G2/M checkpoint. Lymphoblastoid cell lines (LCLs) treated with a G2/M initiating drug azelaic bishydroxamine (ABHA) did not show a G2/M checkpoint response, but rather they display an increase in cell death, a characteristic of sensitivity to the cytotoxic effects of the drug. Cell cycle analysis demonstrated that the individual expression of EBNA-3, -4 or -6 are capable of disrupting the G2/M checkpoint response induced by ABHA resulting in increased toxicity, whereas EBNA-2, and -5 were not. EBNA-3 gene family protein expression also disrupted the G2/M checkpoint initiated in response to the genotoxin etoposide and the S phase inhibitor hydroxyurea. The G2 arrest in response to these drugs were sensitive to caffeine, suggesting that ATM/ATR signalling in these checkpoint responses may be blocked by the EBNA-3 family proteins. The function of EBNA-3, -4 and -6 proteins appears to be more complex than anticipated and these data suggest a role for these proteins in disrupting the host cell cycle machinery.

Pubmed ID: 14716295


  • Krauer KG
  • Burgess A
  • Buck M
  • Flanagan J
  • Sculley TB
  • Gabrielli B



Publication Data

February 19, 2004

Associated Grants


Mesh Terms

  • Ataxia Telangiectasia Mutated Proteins
  • Cell Cycle Proteins
  • Checkpoint Kinase 2
  • DNA Damage
  • DNA-Binding Proteins
  • Epstein-Barr Virus Nuclear Antigens
  • G2 Phase
  • Histone Deacetylase Inhibitors
  • Humans
  • Hydroxamic Acids
  • Mitosis
  • Precipitin Tests
  • Protein-Serine-Threonine Kinases
  • Signal Transduction
  • Tumor Suppressor Proteins