TISSUE SPECIFIC TUMOR INDUCTION BY POLYOMAVIRUS

多瘤病毒通常建立一个沉默的，持续的感染， 自然宿主，老鼠，但在实验条件下， 广泛的溶解性感染并在多达12种不同的 组织，包括胸腺组织中的高频率肿瘤，唾液 腺体和乳腺。尽管这种病毒已经被广泛研究 在细胞培养中，关于其与宿主细胞相互作用知之甚少， 那个禽兽本提案中的实验旨在探索 导致肿瘤组织特异性的病毒-细胞相互作用 由多瘤病毒形成。 这一建议的两个具体目标基于以下假设： 与细胞因子相互作用的病毒调节序列， 负责组织特异性肿瘤诱导。第一个目标是 定义负责组织特异性的病毒遗传决定因素 通过评估含有以下物质的病毒的肿瘤特征， 潜在调控序列的突变。这些调控区域 包括40 bp重复的序列的起源的早期一侧， 复制，我们以前已经证明是必要的， 胸腺上皮瘤的诱导，以及多瘤增强子序列， 对于细胞培养系统中的病毒调节是重要的。我们的第二 我们的目标是利用这些调控序列来鉴定和表征 与之结合的细胞因子DNA结合蛋白将被 通过凝胶迁移和足迹实验鉴定，并进一步 通过紫外交联实验和亲和层析进行表征。 多瘤病毒基因的表达和复制，以及致癌基因 由病毒触发的途径，利用细胞因子， 通常参与信号传导和细胞生长控制， 在许多非病毒病因的癌症中发生改变。 因此，理解 多瘤病毒在分子水平上的肿瘤诱导和鉴定 顺式作用序列和细胞因子参与组织 肿瘤形成的特异性将提供新的信息， 细胞生长控制和癌症领域。

Polyomavirus normally establishes a silent, persistent infection in its natural host, the mouse, but under experimental conditions can cause widespread lytic infection and induce tumors in up to a dozen different tissues, including a high frequency of tumors in thymic tissue, salivary glands and mammary glands. Although the virus has been studied extensively in cell culture, little is known about its interaction with host cells in the animal. The experiments in this proposal are designed to explore the virus-cell interactions that result in tissue specificity of tumor formation by polyomavirus. The two specific aims in this proposal are based on the hypothesis that viral regulatory sequences interacting with cellular factors are responsible for tissue specific tumor induction. The first goal is to define the viral genetic determinants responsible for tissue specific tumorigenesis by evaluating the tumor profile of viruses containing mutations in potential regulatory sequences. These regulatory regions include a 4Obp duplication of sequences on the early side of the origin of replication that we have previously shown to be necessary for the induction of thymic epitheliomas, and the polyoma enhancer sequences that are important for virus regulation in cell culture systems. Our second goal is to use these regulatory sequences to identify and characterize the cellular factors that bind to them. The DNA binding proteins will be identified by gel shift and footprinting experiments and further characterized by UV crosslinking experiments and affinity chromatography. Polyomavirus gene expression and replication, as well as the oncogenic pathways triggered by the virus, utilize cellular factors that are normally involved in signal transduction and cell growth control, and that are altered in many cancers of non-viral etiology. Thus, understanding tumor induction by polyomavirus at the molecular level and identifying cis-acting sequences and cellular factors involved in the tissue specificity of tumor formation will provide new information relevant to the fields of cell growth control and cancer.