NEOPLASTIC TRANSFORMATION BY RAS ONCOGENES

我们建议研究突变的机制， ras癌基因导致肿瘤转化，使用 果蝇作为一个模型系统。 我们已经建立了果蝇 在其种系中含有激活的ras基因的菌株; 该基因的表达导致生长模式的改变， 发育中的果蝇的各种组织的分化，取决于 在转化基因的诱导时间上。 在这 应用程序，我们提出了一个双重的方法，以进一步我们的 理解ras编码的蛋白质在 细胞的生理学。 首先，我们将详细研究在 细胞水平ras基因引起的异常表型 使用免疫荧光和电子显微镜 显微技术。 我们会特别研究 发生在发育中的眼睛想象的结构变化 使用特异性抗体活化ras转化果蝇的圆盘 染色感光细胞;类似的改变将被分析 在蛹后期，通过连续切片的电子显微镜观察 通过发育中的眼睛。 这些信息将使我们能够 确定受影响的生物过程的确切性质 激活ras基因表达， ras蛋白在生长和发育中作用的假说 分化 第二种方法是隔离第二种- 逆转或增强表型效应的位点突变 激活ras蛋白表达。 这些基因座将被克隆， 杂种发育不全和/或染色体步移。 的 由这些蛋白质编码的蛋白质产物的表征 修饰基因将提供识别因子， 在代谢水平上与ras蛋白相互作用， 为了解人体的生理功能提供了重要线索 拉斯

We propose to investigate the mechanisms by which mutations in the ras oncogene result in neoplastic transformation, using Drosophila as a model system. We have established Drosophila strains that contain an activated ras gene in their germline; the expression of this gene results in altered patterns of growth and differentiation of various tissues of the developing fly, depending on the time of induction of the transformed gene. In this application we propose a dual approach to further our understanding of the role of the ras-encoded protein in the physiology of the cell. First we will examine in detail at the cellular level the aberrant phenotypes caused by ras overexpression using immunofluorescent and electron microscopical techniques. In particular, we will study the structural alterations that occur in the developing eye imaginal discs of activated ras-transformed flies using specific antibodies that stain photoreceptor cells; similar alterations will be analyzed during late pupal stages by electron microscopy of serial sections through the developing eye. This information will allow us to identify the exact nature of the biological processes affected by activated ras expression and will make possible to establish hypotheses on the role of ras protein in growth and differentiation. The second approach will be to isolate second- site mutations that reverse or enhance the phenotypic effect of activated ras protein expression. These loci will be cloned using hybrid dysgenesis and/or chromosomal walking. The characterization of the protein products encoded by these modifier genes will afford the identification of factors that interact with ras protein at the metabolic level and will therefore offer important clues to understand the physiological function of ras.