The viral proteins, latent membrane protein 1 (LMP1) and latent membrane protein 2 (LMP2), are expressed in many of the malignancies associated with EBV. We have previously produced and characterized transgenic mice that express LMP1 in B-lymphocytes using the immunoglobulin heavy chain promoter/enhancer (Ig-LMPl). These mice develop clonal B-cell lymphomas that express LMP1 at high levels. The clonal development of these cancers indicates that additional genetic changes must occur that complement the cellular pathways activated by LMP1. During this last period of funding, we have identified remarkable oncogenic synergy between the loss of the p16INK4/p19ARF locus and expression of LMP1 in B-lymphocytes. To evaluate the effects of LMP1 on epithelial cell growth, we have produced transgenic mice that express LMP1 under the control of the keratin 14 (K14) promoter. In these mice using classical tumor initiation and promotion analyses, LMP1 functions largely as a tumor promoter with a possible role in tumor progression. Transgenic mice that express LMP2 in B-lymphocytes using the Ig promoter and in epithelial cells from the K14 promoter have been obtained from Dr. Richard Longnecker. The K14-LMP2 transgenic mice will be tested to determine if LMP2 affects the oncogenic process through initiation, promotion, or progression in skin tests. Possible synergistic effects of LMP1 and LMP2 expression on B-cell and epithelial cell growth will be analyzed in dually transgenic mice and in transformation assays in vitro. Our specific aims are: 1) The transgenic LMP1+ lymphocytes, LMP1+ lymphomas, LMP1+ p16 null lymphomas, and LMP1+ p53 heterozygous lymphomas will be further characterized to identify activated signaling pathways and effects on cellular gene expression. The growth properties of the LMP1+ lymphocytes and lymphoma cells will be analyzed in vitro. 2) LMP1 and LMP2 affect and activate distinct cellular signaling pathways. To test the hypothesis that coordinate expression of LMP1 and LMP2 activates complementing pathways that synergistically alter growth regulation, Ig-LMP1/LMP2 transgenic mice will be produced by cross-breeding. The time to tumor development and the growth and biochemical properties of the cells in vitro will be determined. 3) To determine the effects of expression of LMP1 and LMP2 in normal epithelial cells, K14 promoter transgenic mice that express LMP1 and/or LMP2 in epithelial cells will be tested in classic skin carcinogenesis assays in combination with exposure to carcinogens and tumor promoters. 4) Characterize LMP1 transformation of rodent fibroblasts. The essential domains of LMP1 will be identified and the signaling pathways that are activated will be determined. The effects on rodent fibroblast growth properties of LMP1 alone and in the absence of the p16 and p19 tumor suppressor genes will be determined.