FUNCTIONAL ANALYSIS OF A PDGF-INDUCIBLE CYTOKINE

生长因子对靶细胞的作用部分是通过诱导 特定基因的表达。例如，在3T3细胞中， 血小板衍生生长因子(PDGF)诱导血管内皮生长因子的表达 与增殖相关的原癌基因以及另外50-100个 基因，其中大多数没有已知的功能。的长期目标是 这项提议是为了了解更多关于生长因子介导的有丝分裂的信息。 进程，通过了解一些 后一组PDGF诱导基因，特别是je基因，第一 PDGF易感基因已被分离。 在初步研究中，乙脑基因已被证明编码一个低水平的 分子量分泌的糖蛋白，与最近的 纯化的单核细胞趋化因子。该因子还能激活单核细胞， 增强他们参与抗体非依赖性肿瘤细胞裂解的能力。 因此，这一应用领域的研究也将与抗肿瘤相关 心理治疗。这项提案的具体目标将有三个假设 测试： 首先，因为乙脑蛋白在纳米分子上发挥作用。 浓度，它很可能通过高亲和力受体起作用。这个 第一个具体目标是识别、克隆和测试这些基因的活性 感受器。这些实验将为我们深入了解 单核细胞趋化和激活，以及提供工具 检查其他细胞类型是否存在乙脑受体。 其次，因为乙脑蛋白的序列与那些 在具有不同活性的其他细胞因子中，很可能其 单核细胞特异性效应是通过特定的氨基酸来调节的。这个 第二个具体目标是执行JE的结构/功能分析 蛋白质的定点突变。这项研究的结果可能 为开发特定的激动剂或拮抗剂提供信息 我的行动。 最后，因为存在能够表达JE的单元格类型 在炎症反应中没有作用，乙脑很可能有 除单一趋化作用外的其他功能。第三个具体目标是 去调控方式表达乙脑的转基因小鼠的构建。在……里面 除了揭示乙脑的新活动的可能性外，该模型 还将在体内确认乙脑对单次注射的影响 生理学。

Growth factors exert their effects on target cells, in part, by inducing the expression of specific genes. For example, in 3T3 cells, platelet-derived growth factor (PDGF) induces the expression of proliferation-related proto-oncogenes as well as an additional 50-100 genes, the majority of which have no known function. The long-term goal of this proposal is to learn more about growth factor-mediated mitogenic processes by understanding the structure and function of some of the the latter group of PDGF-inducible genes, in particular the JE gene, the first PDGF-indudble gene to have been isolated. In preliminary studies, the JE gene has been shown to encode a low molecular weight secreted glycoprotein that is identical to a recently purified monocyte chemotactic factor. This factor also activates monocytes, enhancing their ability to engage in antibodyindependent tumor cell lysis. Thus the studies in this application will also have relevance to anti-tumor therapy. There are three hypotheses the specific aims of this proposal will test: First, because the JE protein exerts its effects at nanomolar concentrations, it is likely to act through a high affinity receptor. The first specific aim is to identify, clone, and test the activity of these receptors. These experiments will provide insight into the mechanisms of monocyte chemotaxis and activation, as well as providing tools for the examination of other cell types for the presence of the JE receptor. Second, because the sequence of the JE protein is highly similar to those of other cytokines with different activities, it is likely that its monocyte-specific effects are mediated through specific amino acids. The second specific aim is to perform a structure/function analysis of the JE protein by site-directed mutagenesis. The results of such a study could provide information for the development of specific agonists or antagonists of JE action. Finally, because there are cell types capable of expressing JE that play no role in the inflammatory response, it is likely that JE may have functions other than monocute chemotaxis. The third specific aim is the construction of transgenic mice expressing JE in a deregulated fashion. In addition to the potential for revealing new activities for JE, this model will also provide in vivo confirmation of JE's effects on monocute physiology.