TRANSFORMATION BY EBV LATENT MEMBRANE PROTEIN 1

EB病毒潜伏膜蛋白（LMP 1）在大多数与EB病毒相关的恶性肿瘤中表达，并且其在淋巴和上皮细胞系中的表达深刻地影响其生物表型和基因表达。LMP 1是唯一能使永生化啮齿类成纤维细胞系在裸鼠中失去接触抑制、降低血清依赖性、锚定不依赖性和致瘤性的EBV基因。LMP 1与肿瘤坏死因子受体（TNFR）相关因子（TRAFS）相互作用，通过该相互作用，LMP 1激活NFkB转录因子和JNK激酶。我们已经产生了三个谱系的LMP 1转基因小鼠，其中LMP 1在重链免疫球蛋白启动子/增强子的控制下表达。小鼠的B细胞淋巴瘤的发展增加了5倍，其中LMP 1在淋巴瘤组织中以高水平表达。这一结果表明，LMP 1，没有其他EBV基因的表达，是致癌的体内，并表明，LMP 1是一个主要的促进因素，发展的EBV相关的淋巴瘤。我们还表明，LMP 1诱导表皮生长因子受体（EGFR）的表达，通过TRAF相互作用域和突变的TRAF相互作用产生了两个温度敏感的突变体方面的EGFR诱导。我们的初步数据表明，LMP 1也诱导啮齿动物成纤维细胞中EGFR的表达。在这项资助中，我们将确定LMP 1介导的转化的生化基础，并确定有助于肿瘤发生的细胞基因。我们的具体目标是：1）通过鉴定LMP 1和活化的信号传导途径的分子相互作用来进一步表征转基因淋巴瘤，2）确定转基因小鼠中LMP 1的表达是否与核癌基因c-myc的活化协同作用，3）确定肿瘤抑制因子p53的失活是否增加转基因小鼠中LMP 1的恶性潜能，4）通过鉴定LMP 1的必需结构域和被激活的信号传导途径来表征啮齿动物成纤维细胞的LMP 1转化，5）使用EGFR信号传导抑制剂和两种温度敏感形式的LMP 1来确定LMP 1对啮齿动物成纤维细胞转化的EGFR诱导的贡献。

The Epstein-Barr virus (EBV) latent membrane protein (LMP1) is expressed in most of the malignancies associated with EBV and its expression in lymphoid and epithelial cell lines profoundly affects their biologic phenotype and gene expression. LMP1 is the only EBV gene that can transform immortalized rodent fibroblast lines to loss of contact inhibition, lower serum dependence, anchorage independence, and tumorigenicity in nude mice. LMP1 interacts with the tumor necrosis factor receptor (TNFR) associated factors (TRAFS) through which it activates the NFkB transcription factor and JNK kinase. We have generated three lineages of LMP 1 transgenic mice with LMP l expressed under the control of the heavy chain immunoglobulin promoter/enhancer. The mice have a 5 fold increase in the development of B cell lymphoma with LMP1 expressed at high levels in the lymphoma tissues. This result indicates that LMP1, without expression of other EBV genes, is oncogenic in vivo and suggests that LMP1 is a major contributing factor to the development of EBV-associated lymphomas. We have also shown that LMP1 induces the expression of epidermal growth factor receptor (EGFR) through the TRAF interacting domain and by mutating the TRAF interacting have produced two temperature sensitive mutants with regard to EGFR induction. Our preliminary data indicates that LMP1 also induces expression of the EGFR in rodent fibroblasts. In this grant, we will determine the biochemical basis of LMP1-mediated transformation and identify cellular genes that contribute to oncogenesis. Our specific aims are to l) further characterize the transgenic lymphomas by identifying the molecular interactions of LMP1 and the activated signaling pathways, 2) determine if LMP1 expression in transgenic mice synergizes with activation of the nuclear oncogene, c-myc, 3) determine if inactivation of the tumor suppressor, p53, increases the malignant potential of LMP1 in transgenic mice, 4) characterize LMP l transformation of rodent fibroblasts by identifying the essential domains of LMP1 and the signaling pathways that are activated, 5) determine the contribution of EGFR induction by LMP1 to rodent fibroblast transformation using inhibitors of EGFR signaling and two temperature sensitive forms of LMP1.