BPV-1 E5--FUNCTIONAL INTERACTIONS & CELL TRANSFORMATION

BPV-1 E5--功能相互作用

• 批准号: 2104638
• 负责人: DAVID J GOLDSTEIN
• 金额: $ 10.44万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-05-01 至 1999-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2104638
• 关键词: biological signal transduction; bovine papillomavirus; cell growth regulation; cell transformation; chimeric proteins; clone cells; conformation; cytokine receptors; epidermal growth factor; flow cytometry; growth factor receptors; human papillomavirus; immunoprecipitation; mutant; oncoproteins; phosphorylation; platelet derived growth factor; protein isoforms; protein tyrosine kinase; receptor binding; site directed mutagenesis; transfection; transforming virus; virus protein; western blottings

The correlation between papillomavirus infection and the development of human cancer is well established and the viral genes involved in this process have been identified. It is becoming increasingly evident that the ability of the papillomaviruses to induce cellular proliferation involves complex formation with certain cellular proteins that are important for the regulation of cell growth. A consequence of these interactions appears to be an alteration of the function of these proteins resulting in mitogenesis and transformation. The E5 protein is the major transforming protein expressed by the prototype bovine papillomavirus type 1 (BPV-1). It is unique in that it is highly hydrophobic, localizes predominantly to Golgi and endomembrane compartments, and consists of only 44 amino acids. Many of the human papillomaviruses (HPVs) also encode small, hydrophobic E5 proteins. However, our current knowledge of the activity of these structurally related E5 proteins is only rudimentary. Several recent studies on both the HPV and BPV E5 proteins suggest an involvement of tyrosine kinase growth factor receptors in the induction of cellular mitogenesis. This research grant application proposes to demonstrate that mitogenetic and transforming activity induced by the BPV-1 E5 protein is a direct consequence of the activation of growth factor receptors. In addition, we intend to define the molecular and biochemical mechanisms involved in the process of receptor activation. The molecular cloning of growth factor receptor genes has made it feasible to investigate the ability of specific receptors to couple with intracellular components needed to evoke a functional response in foreign host cells. To investigate the ability of the E5 proteins to induce mitogenic signalling through growth factor receptors, a nontumorigenic, murine myeloid cell line (32D) which is strictly dependent on interleukin 3 (IL-3) for sustained proliferation in culture will be employed. The strict requirement for IL-3 for the growth of 32D cells can be functionally substituted by the stimulation of signal transduction pathways initiated by the expression of specific growth factor receptors and the addition of the appropriate ligand to the culture medium. This phenomenon will be exploited to identify and characterize those components of signal transduction pathways that are capable of responding to E5 expression to induce mitogenesis and cellular transformation in the absence of ligand. The data generated from these studies, in addition to assisting in the elucidation of the complex mechanism of papillomavirus transformation, may also provide new insights into molecular aspects of growth factor receptor tyrosine kinases, receptor-mediated signal transduction, and the control of cell growth. As a long-term goal of this project, a similar approach will be applied to the structurally homologous HPV E5 proteins. This approach should assist in the identification of the function(s) and cellular targets of these less well-characterized proteins.

乳头瘤病毒感染与乳腺癌发生的相关性 人类癌症是公认的，与此相关的病毒基因 过程已经确定。越来越明显， 乳头瘤病毒诱导细胞增殖的能力包括 与某些细胞蛋白质形成复合物， 细胞生长的调节。这些相互作用的结果似乎 是这些蛋白质功能的改变， 有丝分裂和转化。E5蛋白是主要的转化蛋白 由原型牛乳头瘤病毒1型（BPV-1）表达的蛋白。 它的独特之处在于它是高度疏水的，主要定位于 高尔基体和内膜室，并由只有44个氨基酸。 许多人乳头瘤病毒（HPV）也编码小的疏水性蛋白， E5蛋白。 然而，我们目前对这些活动的了解 结构上相关的E5蛋白只是初步的。最近的几 对HPV和BPV E5蛋白的研究表明， 酪氨酸激酶生长因子受体在诱导细胞凋亡中的作用 有丝分裂这项研究资助申请旨在证明， BPV-1 E5蛋白诱导的有丝分裂和转化活性是 生长因子受体激活的直接结果。在 此外，我们打算定义的分子和生化机制 参与受体激活过程。的分子克隆 生长因子受体基因使得研究 特异性受体与细胞内成分偶联的能力 需要在外来宿主细胞中引起功能性反应。到 研究E5蛋白诱导促有丝分裂信号传导的能力 通过生长因子受体，一种非致瘤性的鼠骨髓细胞， 系（32 D），其严格依赖于白细胞介素3（IL-3）， 将采用培养中的持续增殖。严格 32 D细胞生长对IL-3的需求可以在功能上是 被信号转导途径的刺激所取代 通过表达特异性生长因子受体和添加 合适的配体。这一现象将在 用于识别和表征信号的这些分量 能够响应E5表达的转导途径， 在配体不存在的情况下诱导有丝分裂和细胞转化。 这些研究产生的数据除了有助于 阐明乳头瘤病毒转化的复杂机制， 也为生长因子受体的分子方面提供了新的见解 酪氨酸激酶、受体介导的信号转导和对照 细胞的生长。作为本项目的长期目标， 将应用于结构同源的HPV E5蛋白。这 方法应有助于确定职能， 这些不太明确的蛋白质的细胞靶点。