RIBOSOMAL GENES OF YEAST AND THEIR REGULATION

核糖体的合成是一个复杂但受到严格调控的过程， 细胞合成等摩尔量的四种核糖体RNA， 细胞核和细胞质中的75种核糖体蛋白， 将它们组装成核仁中的核糖体。 的调节 核糖体的合成是调节生长的关键方面， 基本上所有的生物。 这项提案将使用一种主要是遗传的 研究这种调节机制的方法， 酿酒酵母，目的是阐明一般调控 机制，以及理解细胞如何协调表达 大量的基因。 我们将研究核糖体RNA合成的调节， 关于增强子元件在结构中的作用的假说 串联rRNA基因的排列，以及关于 通过转录间隔区发挥作用的调节机制。 我们 将探索多种转录的协调调节 100个核糖体蛋白基因，通过鉴定突变体， 积极或消极的控制功能。 这样的突变体将被检查 以深入了解协调调节背后的机制。 S.酿酒酵母具有许多丰富的DNA结合蛋白， 多样的功能。 一种这样的蛋白质，称为REB 1，与rDNA结合， 转录控制区和其他地方。 在确定和 纯化REB 1，克隆并测序其基因，我们现在将探索其 通过分析温度敏感突变体的表型， REB 1及其抑制剂。 我们不仅希望了解这种蛋白质 功能，还包括细胞的其他成分可能与之相互作用。 REB 1似乎与癌基因myb共享一个不寻常的DNA结合域。 通过酵母蛋白的靶向突变，我们期望更多地了解 这种DNA-蛋白质相互作用的特征。

The synthesis of ribosomes is a complex but tightly regulated process in which the cell synthesizes equimolar amounts of the four ribosomal RNAs in the nucleus, and of seventy-five ribosomal proteins in the cytoplasm, and assembles them into a ribosome in the nucleolus. The regulation of the synthesis of ribosomes is a key aspect of the regulation of growth in essentially all organisms. This proposal will use a largely genetic approach to study the mechanisms responsible for such regulation in Saccharomyces cerevisiae, with the aim of elucidating general regulatory mechanisms, and of understanding how cells can coordinate the expression of a large number of genes. We will examine the regulation of synthesis of ribosomal RNA with regard to hypotheses on the role of the enhancer element in the structural arrangement of the tandem rRNA genes, and with regard to the possibility of a regulatory mechanism acting through the transcribed spacer region. We will explore the coordinate regulation of the transcription of more than 100 ribosomal protein genes by identifying mutants that have lost either positive or negative control function. Such mutants will then be examined to provide insights into the mechanisms behind the coordinate regulation. S. cerevisiae has a number of abundant DNA binding proteins of apparently diverse function. One such protein, termed REB1, binds to the rDNA transcriptional control regions and elsewhere. Having identified and purified REB1, and cloned and sequenced its gene, we now will explore its function by analysis of the phenotypes of temperature sensitive mutants in REB1 and their suppressors. We expect to learn not only how such a protein functions but also what other components of the cell may interact with it. REB1 appears to share an unusual DNA binding domain with the oncogene, myb. By targeted mutation of the yeast protein we expect to learn more about the characteristics of such DNA-protein interactions.