GENETICS AND ISOLATION OF A EUKARYOTIC CONTROL PROTEIN

这项工作的长期目标是了解基因的控制， 在真核细胞中表达。 我们用尿囊素降解剂 酵母酿酒酵母系统作为这些的模型系统 调查事务所 尿囊素在该生物体中通过以下作用降解： 五种酶的活性，并需要四个额外的参与 运输系统。 所有负责这些功能的基因都有 被映射。 在过去的工作中，我们已经表明，生产的五种酶， 活动和运输系统之一是可诱导的;脲基甲酸酯， 该途径中的最后一个中间体充当诱导物。 我们最近 分离出了两类新的突变体 一类菌株（在 dur 5基因座）在缺乏 添加诱导剂。 第二类菌株（dal 6基因座突变）是 不能合成任何酶，即使诱导剂可以显示出 存在于细胞中。 在本申请中，我们提出使用这些 突变体，以阐明参与控制五个 与尿囊素降解相关的不同基因。 主要方面的 研究包括：（1）突变体的特性，其中生产的 尿囊素降解酶已经改变（dur 5和dal 6），（2） 通过遗传学研究阐明控制元件的相互作用， 第二代对照突变体的分离，（3）dur 5和 dal 6基因，（4）dur 5和dal 6基因表达的表征和（5） 纯化dur 5和dal 6基因产物。

The long range objective of this work is to understand the control of gene expression in eucaryotic cells. We are using the allantoin degradative system of the yeast Sacchaormyces cerevisiae as a model system for these investigations. Allantoin is degraded in this organism by the action of five enzyme activities and requires the additional participation of four transport systems. All of the genes responsible for these functions have been mapped. In past work we have shown that production of the five enzyme activities and one of the transport systems is inducible; allophanate, the last intermediate in the pathway serves as inducer. We have recently isolated two new classes of mutants. One class of strains (mutated in the dur5 locus) produces all of the enzymes constitutively in the absence of added inducer. The second class of strains (mutated in the dal6 locus) are unable to synthesize any of the enzymes even though inducer can be shown to exist in the cells. In the present application we propose to use these mutants to elucidate the molecular events involved in control of the five distinct genes associated with allantoin degradation. The principal areas of study include: (1) characterization of mutants in which production of the allantoin degrading enzymes has been altered (dur5 and dal6), (2) elucidation of control element interactions by genetic studies and the isolation of second generation control mutants, (3) cloning of the dur5 and dal6 genes, (4) characterization of dur5 and dal6 gene expression and (5) purification of the dur5 and dal6 gene products.