Epstein-Barr virus nuclear antigen 2 trans-activates the cellular antiapoptotic bfl-1 gene by a CBF1/RBPJ kappa-dependent pathway

J Virol. 2006 Aug;80(16):8133-44. doi: 10.1128/JVI.00278-06.

Abstract

The human herpesvirus Epstein-Barr virus (EBV) establishes latency and promotes the long-term survival of its host B cell by targeting the molecular machinery controlling cell fate decisions. The cellular antiapoptotic bfl-1 gene confers protection from apoptosis under conditions of growth factor deprivation when expressed ectopically in an EBV-negative Burkitt's lymphoma-derived cell line (B. D'Souza, M. Rowe, and D. Walls, J. Virol. 74:6652-6658, 2000), and the EBV latent membrane protein 1 (LMP1) and its cellular functional homologue CD40 can both drive bfl-1 via an NF-kappaB-dependent enhancer element in the bfl-1 promoter (B. N. D'Souza, L. C. Edelstein, P. M. Pegman, S. M. Smith, S. T. Loughran, A. Clarke, A. Mehl, M. Rowe, C. Gélinas, and D. Walls, J. Virol. 78:1800-1816, 2004). Here we show that the EBV nuclear antigen 2 (EBNA2) also upregulates bfl-1. EBNA2 trans-activation of bfl-1 requires CBF1 (or RBP-J kappa), a nuclear component of the Notch signaling pathway, and there is an essential role for a core consensus CBF1-binding site on the bfl-1 promoter. trans-activation is dependent on the EBNA2-CBF1 interaction, is modulated by other EBV gene products known to interact with the CBF1 corepressor complex, and does not involve activation of NF-kappaB. bfl-1 expression is induced and maintained at high levels by the EBV growth program in a lymphoblastoid cell line, and withdrawal of either EBNA2 or LMP1 does not lead to a reduction in bfl-1 mRNA levels in this context, whereas the simultaneous loss of both EBV proteins results in a major decrease in bfl-1 expression. These findings are relevant to our understanding of EBV persistence, its role in malignant disease, and the B-cell developmental process.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Viral / genetics
  • Apoptosis / genetics
  • B-Lymphocytes / virology
  • Base Sequence
  • Binding Sites
  • Cells, Cultured
  • Epstein-Barr Virus Nuclear Antigens / genetics
  • Epstein-Barr Virus Nuclear Antigens / metabolism*
  • Herpesvirus 4, Human / growth & development*
  • Humans
  • Immunoglobulin J Recombination Signal Sequence-Binding Protein / metabolism*
  • Minor Histocompatibility Antigens
  • Molecular Sequence Data
  • Promoter Regions, Genetic
  • Proto-Oncogene Proteins c-bcl-2 / genetics*
  • RNA, Messenger / analysis
  • RNA, Messenger / metabolism
  • Receptors, Notch / metabolism
  • Repressor Proteins / metabolism
  • Transcriptional Activation*
  • Viral Matrix Proteins / genetics
  • Viral Matrix Proteins / metabolism
  • Viral Proteins

Substances

  • Antigens, Viral
  • BCL2-related protein A1
  • EBNA-2 protein, Human herpesvirus 4
  • EBNA-3A antigen
  • EBNA-3B antigen
  • EBNA-3C, epstein-barr virus
  • EBV-associated membrane antigen, Epstein-Barr virus
  • Epstein-Barr Virus Nuclear Antigens
  • Immunoglobulin J Recombination Signal Sequence-Binding Protein
  • Minor Histocompatibility Antigens
  • Proto-Oncogene Proteins c-bcl-2
  • RBPJ protein, human
  • RNA, Messenger
  • Receptors, Notch
  • Repressor Proteins
  • Viral Matrix Proteins
  • Viral Proteins