bcl-xL and RAG genes are induced and the response to IL-2 enhanced in EmuEBNA-1 transgenic mouse lymphocytes.

We have described transgenic mice expressing Epstein-Barr virus (EBV) nuclear antigen-1 (EBNA-1) in B-cells which show a predisposition to lymphoma. To investigate the underlying oncogenic mechanisms, we have cross bred transgenic strains of mice, examined the pre-tumour B-cell phenotype and investigated the expression levels of selected cellular genes as a response to EBNA-1 expression. We have found that bcl-xL and the recombination activating genes (RAG) 1 and 2 are induced in pre-neoplastic samples of EBNA-1 expressing mice. Induction of bcl-xL may explain the observed redundancy in lymphomagenesis between transgenic EBNA-1 and bcl-2. In addition, bone marrow cells derived from the EmuEBNA-1 mice show a greater capacity for cultured growth compared to controls, particularly in the presence of IL-2. Notably, bcl-xL expression is responsive to IL-2. These data shed new light on the potential contribution of EBNA-1 to EBV associated tumorigenicity as well as to the viral life cycle and open a potential avenue for therapeutic intervention.