NEOPLASTIC TRANSFORMATION BY RAS ONCOGENES

我们建议研究基因突变的机制。 Ras癌基因导致肿瘤转化，使用 以果蝇为模型系统。我们已经建立了果蝇 在其种系中包含激活的ras基因的菌株； 该基因的表达导致生长和生长模式的改变 发育苍蝇不同组织的分化，依赖于 关于转化基因诱导的时间。在这 我们提出了一种双重方法来进一步提高我们的 了解ras编码蛋白在细胞周期调控中的作用 细胞的生理学。首先，我们将在 细胞水平ras引起的异常表型 利用免疫荧光和电子技术实现过表达 显微技术。我们会特别研究 想象中发育中的眼睛发生的结构变化 利用特异性抗体激活ras基因转化果蝇的视盘 对感光细胞进行染色；类似的变化将被分析 用连续切片的电子显微镜观察幼虫的发育 通过发育的眼睛。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 激活了RAS表达，并将可能建立 关于ras蛋白在生长和发育中作用的假说 差异化。第二种方法将是分离第二个- 反转或增强表型效应的位点突变 激活ras蛋白表达。这些基因座将使用以下方法克隆 杂交不育和/或染色体行走。这个 它们编码的蛋白质产物的特性 修饰基因将提供对 与ras蛋白在代谢水平上相互作用，因此 为了解细胞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.