S POMBE CAMP SIGNAL PATHWAY

响应环境信号的转录调控包括 细胞用来控制细胞过程的重要机制 生长、分化和发展。在单细胞生物体中， 可用碳源的变化可能会引发剧烈的变化 在参与碳源利用的基因转录和 糖异生作用。例如，葡萄糖导致抑制 利用其他碳所需基因的转录 消息来源。这种现象被称为葡萄糖抑制或 分解的压抑。我的工作重点是FBP1的葡萄糖抑制 (编码1，6-二磷酸果糖酶)在酵母中的转录 裂殖酵母Pombe.S.pombe是一种基因柔韧的生物 在许多方面与高等真核细胞相似。虽然这件事 生物体在……地区得到了广泛而非常成功的开发 细胞周期调控，但在这一领域开展的研究很少 转录调控。我已经确定了一组基因，命名为 葡萄糖所需的Git基因(Git=葡萄糖不敏感转录) 抑制FBP1转录，包括腺苷环化酶基因 (Git2)。携带基因突变的菌株中的转录缺陷 Git2或任何六个额外的git基因被外源cAMP抑制。 这种抑制，以及其他遗传和生化观察， 提示这些基因具有刺激腺苷环化酶的功能。 对葡萄糖的反应。因此，我建议在野外测量cAMP水平 对暴露在葡萄糖中的细胞进行分类，并分析进一步的git2突变 对葡萄糖的反应似乎是有缺陷的。我还提议 对这些git基因和NFT基因(NFT)进行分子分析 突变体存在FBP1转录抑制缺陷；NFT= 不可逆转的FBP1转录)。我会克隆野生型复制品 确定它们的DNA序列，构建空等位基因， 并检查与cAMP水平和FBP1相关的无效表型 抄写。我还将描述自发的git和nft突变体的特征。 通过cAMP分析、遗传分析和FBP1转录分析 确定庞氏链霉菌中腺苷酸环化酶的激活途径。

Transcriptional regulation in response to environmental signals involves important mechanisms employed by cells to control the processes of cell growth, differentiation and development. In unicellular organisms, changes in the carbon source available can trigger dramatic alterations in transcription of genes involved in carbon source utilization and gluconeogenesis. For example, glucose causes the repression of transcription of genes required for the utilization of other carbon sources. This phenomenon has been termed glucose repression or catabolite repression. My work focuses on glucose repression of fbp1 (encoding fructose-1,6bisphosphatase) transcription in the yeast Schizosaccharomyces pombe. S. pombe is a genetically pliable organism that resembles higher eukaryotic cells in many respects. While this organism has been widely and very successfuly exploited in the area of cell cycle control, few studies have been carried out in the area of transcriptional regulation. I have identified aset of genes, designated git genes (git=glucose insensitive transcription), required for glucose repression of fbp1 transcription, including the adenylate cyclase gene (git2). The trasncriptional defect in strains carrying a mutation in git2 or any six additional git genes is suppressed by exogenous cAMP. This suppression, along with other genetic and biochemical observations, suggests that these genes function to stimulate adenylate cyclase in response to glucose. I therefore propose to measure cAMP levels in wild type cells upon exposure to glucose, and to analyze further git2 mutants that appear to be defective in response to glucose. I also propose to carry out molecular analyses of these git genes and of nft genes (nft mutants are defective in depression of fbp1 transcription; nft= nonderepressible fbp1 transcription). I will clone the wild type copies of these genes, determine their DNA sequences, construct null alleles, and examine the null phenotypes with regard to cAMP levels and fbp1 transcription. I will also characterize spontaneous git and nft mutants by cAMP assays, genetic analyses and fbp1 transcriptional assays to identify the pathway for activation of adenylate cyclase in S. pombe.