CLONAL VIRULENCE FEATURES OF THE EBV TERMINAL REGION

在目前的资金期间，我们观察到该航站楼 EB病毒(EBV)细胞内基因组区域显示 它们的限制性片段图谱有显著的变异 从三个个体、同基因的B细胞系直接克隆 病人。此外，我们还发现克隆型阵列 EBV终端区限制性片段被保留 在体内和体外增殖过程中，EBV- 转化的细胞谱系。最重要的影响是 这些发现在这里进行了探索，如下所示。 首先，可以使用EBV末端片段分析来帮助 确定EBV是否感染肿瘤细胞的祖细胞 或者它是否会继发感染肿瘤 最初扩散和扩散后的人口( “乘客病毒”的概念)。在这里，我们建议分析EBV 鼻咽癌标本中的末端区域片段 癌症、非洲伯基特淋巴瘤和艾滋病相关的B- 淋巴瘤来回答这个问题。 第二，我们的发现提出了克隆的一种机制 在EBV相关的恶性肿瘤中观察到优势。病毒基因 编码一种重要的“早期”跨膜蛋白 (IMP/LYDMA)已被其他人本地化到大约 EBV末端0.6kb-重复序列。IMP/LYDMA基因 产品被认为在EBV的免疫识别中起重要作用- 被感染的细胞，并可能在细胞转化中。我们建议 在细胞内DNA中观察到的克隆异质性 病毒末端区域与顺式作用效应有关 IMP/LYDMA转录；此处确实提供了证据 表明IMP/LYDMA转录的克隆性变异。我们 建议进一步分析其结构和功能。 细胞内EBV终端区。第一，自然和地理位置 末端区域DNA克隆异质性的研究将进一步 在我们的肿瘤组织细胞克隆中进行了分析。第二，数量上的 将获得IMP/LYDMA的克隆转录估计。 第三，细胞内染色质结构的克隆性变异 将对EBV终端区进行研究。最后，一个集合的成员 的同源细胞克隆将进行个体测试 对自体效应细胞杀伤的敏感性，在 细胞毒性试验；这些结果将与 IMP/LYDMA克隆转录的定量估计。 拟议中的研究利用当前的发现来辨别特征 在克隆过程中可能很重要的EBV末端区域 EB病毒诱导的显性与肿瘤发生。

In the present funding period, we observed that the terminal regions of intracellular Epstein-Barr virus (EBV) genome exhibit marked variation in their restriction-fragment profile in individual, isogenic B-cell lineages cloned directly from three patients. Furthermore, we found that the clonotypic arrays of EBV terminal-region restriction fragments are maintained relatively stably, during in vivo and in vitro proliferation of EBV- transformed cell lineages. The most important implications of these findings are explored here, as follows. First, EBV terminal-fragment analysis can be used to help determine whether EBV infects the progenitor cell of tumor-cell populations, or whether it secondarily infects the tumor population after initial proliferation and dissemination (the "passenger virus" notion). Here, we propose to analyze the EBV terminal-region fragment in tumor specimens of nasopharyngeal carcinoma, African Burkitt Lymphoma, and AIDS-related B- lymphomas to answer this question. Second, our findings suggest one mechanism of the clonal dominance observed in EBV-related malignancies. The viral gene encoding an important 'early' transmembrane protein (IMP/LYDMA) has been localized by others to a site within about 0.6 kb of the EBV terminal-repeats. The IMP/LYDMA gene product is thought to be important in immune recognition of EBV- infected cells, and possibly in cell transformation. We suggest that the clonal heterogeneity observed in the DNA of intracellular viral terminal regions is associated with cis-acting effects on IMP/LYDMA transcription; evidence provided here indeed indicates clonal variation in IMP/LYDMA transcription. We propose to further analyze the structure and function of intracellular EBV terminal regions. First, the nature and location of clonal heterogeneity of terminal-region DNA will be further analyzed in our cell clones in tumor tissues. Second, quantitative estimates of clonal transcription of IMP/LYDMA will be obtained. Third, clonal variation in the chromatin structure of intracellular EBV terminal regions will be studied. Finally, members of one set of isogenic cell clones will be tested for their individual susceptibility to killing by autologous effector cells, in cytotoxicity assays; and these results will be correlated with the quantitative estimates of clonal transcription of IMP/LYDMA. The proposed studies utilize current findings to discern features of the EBV-terminal region which may be important in clonal dominance and tumorigenesis induced by EBV.