LMP1 signaling and activation of NF-kappaB in LMP1 transgenic mice

Oncogene. 2006 Jan 12;25(2):288-97. doi: 10.1038/sj.onc.1209023.


Transgenic mice expressing Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) under the control of an immunoglobulin heavy-chain promoter and enhancer develop lymphoma at a threefold higher incidence than LMP1-negative mice. In vitro, LMP1 activates numerous signaling pathways including p38, c-Jun N terminal kinase (JNK), phosphatidylinositol 3 kinase (PI3K)/Akt, and NF-kappaB through interactions with tumor necrosis receptor-associated factors (TRAFs). These pathways are frequently activated in EBV-associated malignancies, although their activation cannot be definitively linked to LMP1 expression in vivo. In this study, interactions between LMP1 and TRAFs and the activation of PI3K/Akt, JNK, p38, and NF-kappaB were examined in LMP1 transgenic mice. LMP1 co-immunoprecipitated with TRAFs 1, 2, and 3. Akt, JNK, and p38 were activated in LMP1-positive and -negative splenocytes as well as LMP1-positive and -negative lymphomas. Multiple forms of NF-kappaB were activated in healthy splenocytes from LMP1 transgenic mice, in contrast to healthy splenocytes from LMP1-negative mice. However, in both LMP1-positive and -negative lymphomas, only the oncogenic NF-kappaB c-Rel, was specifically activated. Similarly to EBV-associated malignancies, p53 protein was detected at high levels in the transgenic lymphomas, although mutations were not detected in the p53 gene. These data indicate that NF-kappaB is activated in LMP1-positive healthy splenocytes; however, NF-kappaB c-Rel is specifically activated in both the transgenic lymphomas and in the rare lymphomas that develop in negative mice. The LMP1-mediated activation of NF-kappaB may contribute to the specific activation of c-Rel and lead to the increased development of lymphoma in the LMP1 transgenic mice.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Class I Phosphatidylinositol 3-Kinases
  • Cytoskeletal Proteins
  • Genes, rel / physiology*
  • Humans
  • Immunoprecipitation
  • Intracellular Signaling Peptides and Proteins
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • LIM Domain Proteins
  • Lymphoma* / metabolism
  • Lymphoma* / pathology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Transgenic
  • Mitogen-Activated Protein Kinases / metabolism
  • NF-kappa B / metabolism*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Receptors, Cell Surface / metabolism
  • Signal Transduction*
  • Spleen / metabolism
  • TNF Receptor-Associated Factor 1 / metabolism
  • TNF Receptor-Associated Factor 2 / metabolism
  • TNF Receptor-Associated Factor 3 / metabolism
  • Transcription Factor RelB / metabolism
  • Tumor Suppressor Protein p53 / metabolism
  • Viral Matrix Proteins / genetics
  • Viral Matrix Proteins / physiology*


  • Adaptor Proteins, Signal Transducing
  • Cytoskeletal Proteins
  • EBV-associated membrane antigen, Epstein-Barr virus
  • Intracellular Signaling Peptides and Proteins
  • LIM Domain Proteins
  • NF-kappa B
  • PDLIM7 protein, human
  • RELB protein, human
  • Receptors, Cell Surface
  • TNF Receptor-Associated Factor 1
  • TNF Receptor-Associated Factor 2
  • TNF Receptor-Associated Factor 3
  • Tumor Suppressor Protein p53
  • Viral Matrix Proteins
  • Transcription Factor RelB
  • Phosphatidylinositol 3-Kinases
  • Class I Phosphatidylinositol 3-Kinases
  • PIK3CA protein, human
  • Proto-Oncogene Proteins c-akt
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases