REGULATION OF NITROGEN CATABOLIC GENE EXPRESSION

这项工作的长期目标是了解生物化学 负责调节尿囊素系统转录的反应 运输基因 分解代谢抑制的重要组成部分。 尿囊酸通透酶基因DAL 5已被选择作为模型系统， 来研究这种类型的规则。 我们已经确定了上游 激活序列（UAS）负责转录激活 DAL 5，并显示其结合一种或多种蛋白质。 的目的 目前的建议是要大大改善我们对无人机系统的理解 通过改变12-15个碱基， 是转录激活所必需的。 成效为何 支持转录激活和蛋白质表达能力的改变 与UAS的结合将沿着嘌呤的作用进行测量 甲基化对蛋白质结合的影响。 编码蛋白质的基因 DAL 5无人机系统将使用几种建议的策略之一进行克隆。 氮代谢产物阻遏（NCR）的机制将得到解决 使用涉及使用DAL 5和CAR 1的多种策略， 基因. DAL 5 UAS已被证明是唯一的DNA序列 DAL 5基因表达对NCR敏感性所需的信息。 在 相反，上游抑制元件（URS），其行为类似于 在CAR 1基因的NCR中涉及到一个操纵子。 我们提出 详细的实验，以确定是否URS是唯一的顺式作用 NCR灵敏度所需的CAR 1元件。 实验是 建议确定蛋白质磷酸化是否与 CAR 1和DAL 5基因的NCR敏感性。

The long term objective of this work is to understand the biochemical reactions responsible for regulated transcription of the allantoin system transport genes. An important component of this catabolite repression. The allantoate permease gene, DAL5, has been chosen as a model system with which to study this type of regulation. We have identified the upstream activation sequence (UAS) responsible for transcriptional activation of DAL5 and shown that it binds one or more proteins. The objective of the present proposals is to significantly refine our understanding of the UAS structure by altering the 12-15 bases that have been shown to be functionally required for transcriptional activation. The effects of these alterations on ability to support transcriptional activation and protein binding to the UAS will be measured along with the effects of purine methylation on protein binding. The gene encoding the protein that binds to the DAL5 UAS will be cloned using one of several proposed strategies. The mechanisms of nitrogen catabolite repression (NCR) will be addressed using multiple strategies involving the use of both the DAL5 and CAR1 genes. The DAL5 UAS has been demonstrated to be the only DNA sequence information required for sensitivity of DAL5 gene expression to NCR. In contrast, an upstream repression element (URS), which behaves like an operator, has been implicated in NCR of the CAR1 gene. We have proposed detailed experiments to ascertain whether the URS is the only cis-acting element of CAR1 required for NCR sensitivity. Experiments are then proposed to determine whether protein phosphorylation is associated with NCR sensitivity of the CAR1 and DAL5 genes.