GENETIC ANALYSIS OF THE UPSTREAM CONTROL OF YEAST RAS

Ras基因突变与几种人类疾病的发病有关。 肿瘤，但对其生化功能知之甚少 或调节正常或肿瘤细胞中的ras基因产物。为了 为了更深入地了解RAS蛋白的活性控制，我们 建议继续寻找RAS蛋白活性的新调节因子 在模式真核细胞中，酿酒酵母。我们会把 特别注重对小说的识别和刻画 RAS活性的正向调节因子，通过使用具有 已经确定了RAS激活所需的新基因。 RAS的新型正向调节器以及负向调节器WE 之前确定的Rpil，将由一个 分子遗传学和生物化学方法的结合。我们会 利用RAS蛋白激活的特异性生化检测 重组Cac25和重组IRA2蛋白的可能性探讨 根据已知的情况，这些新的调节器的功能 参与RAS调节的蛋白质。 最后，我们建议研究对RAS特定监管机构的要求 CDC25、IRA1、IRA2和RpIL的转导活性 RAS蛋白的特定营养信号。我们的长期目标是获得 参与控制的基因产物的完整分子图谱 RAS活性并确定其生化作用模式。

Mutations in ras genes are involved in the pathogenesis of several human tumors, but relatively little is understood about the biochemical function or regulation of ras gene products in normal or tumor cells. In order to gain more insight into the control of the activity of Ras proteins, we propose to continue our search for novel regulators of Ras protein activity in the model eukaryotic cell, Saccharomyces cerevisiae. We will place special emphasis on the identification and characterization of novel positive regulators of Ras activity, by use of a genetic screen that has already identified a new gene required for Ras activation. Novel positive regulators of Ras, as well as the negative regulator we previously identified called Rpil, will be studied in depth by a combination of molecular genetic and biochemical approaches. We will utilize specific biochemical assays of Ras protein activation involving recombinant Cac25 and recombinant Ira2 proteins to explore the possible function of these novel regulators in light of what is already known about proteins that are involved in Ras regulation. Finally, we propose to study the requirement for specific regulators of Ras activity (e.g., Cdc25, Ira1, Ira2, and Rpil) in the transduction of specific nutrient signals to Ras proteins. Our long term goal is to gain a complete molecular picture of the gene products involved in the control of Ras activity and to determine their biochemical mode of action.