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， 细胞核中有75种核糖体蛋白， 将它们组装成核仁中的核糖体。 我们建议在 酿酒酵母的转录调控机制 核糖体RNA和核糖体蛋白质的合成。 核糖体RNA：我们已经确定了rDNA重复序列中的一个序列， 增强子元素的特性。 我们计划找出 参与这种效应的序列。 我们会问这种增强剂 元素： a）结合特定的转录因子？ B）参与35 S前rRNA的转录调控。 c）负责35 S前rRNA的1：1转录比例， 5S RNA，其基因位于增强子和35 S起始位点之间？ 核糖体蛋白：大多数，如果不是全部， 核糖体蛋白基因是紧密结合的。 为了理解这个机制 在这种偶联背后，我们将鉴定出 转录一个核糖体蛋白基因，然后确定是否相似 序列用于其它核糖体蛋白基因。 我们会问， 相同的序列参与其转录的调节和/或 是否存在对这些基因特异的转录因子。 最后， 我们将分析核糖体翻译控制的机制， 蛋白质合成，重点是测试假设， 调节分子与m7 G帽及其相邻序列相互作用。

The synthesis of ribosomes is a complex but tightly regulated process in which the cell synthesizes equimolar amounts of four ribosomal RNAs in the nucleus, and of seventy-five ribosomal proteins in the cytoplasm, and assembles them into a ribosome in the nucleolus. We propose to study in Saccharomyces cerevisiae the mechanisms controlling both the transcription of ribosomal RNA and the synthesis of ribosomal proteins. Ribosomal RNA: We have identified a sequence in the rDNA repeat with many of the properties of an enhancer element. We plan to identify the precise sequences involved in this effect. We will ask whether this enhancer element: a) binds a specific transcription factor? b) is involved in the regulation of transcription of 35S prerRNA? c) is responsible for the 1:1 ratio of the transcription of 35S prerRNA and 5S RNA, whose gene lies between the enhancer and the 35S initiation site? Ribosomal Protein: The rates of transcription of most, if not all, ribosomal protein genes are tightly coupled. To understand the mechanism behind this coupling we will identify the sequences essential for the transcription of one ribosomal protein gene and then determine if similar sequences are used for other ribosomal protein genes. We will ask if the same sequences are involved in regulation of their transcription and/or whether there is a transcription factor specific for these genes. Finally, we will analyze the mechanism for translational control of ribosomal protein synthesis, with emphasis on testing the hypothesis that a regulatory molecule interacts with the m7G cap and its adjacent sequences.