Transcriptional regulation of carbon utilization in yeast

酵母碳利用的转录调控

• 批准号: 184053-2009
• 负责人: Turcotte, Bernard
• 金额: $ 4.37万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=523028
• 关键词: Transcriptional; regulation; carbon; utilization; yeast

The yeast Saccharomyces cerevisiae preferentially uses glucose as a carbon source. Upon glucose exhaustion, this yeast can use non-sugar carbons (non-fermentable carbons) such as ethanol, lactate and acetate. This results in massive reprogramming of gene expression to adapt to the new carbon source. This process is controlled by the master kinase Snf1 which phosphorylates various substrates including the transcription factors Cat8 and Sip4 that control expression of specific genes by binding to Carbon Source Response Elements found in the promoters of the target genes. For example, these factors upregulate the expression of PCK1 encoding a very important enzyme for gluconeogenesis. Cat8 and Sip4 belong to the Gal4 family of zinc cluster proteins that form an important class of transcriptional regulators in yeast. We have characterized the zinc cluster protein Rds2 by performing genome-wide localization (ChIP-chip) of this factor and found that it is a very important regulator of gluconeogenesis. However, Rds2 and Cat8 show a limited number of common target genes. Thus, they have specific and common functions. We are also characterizing another zinc cluster gene we named ERT1 (for Ethanol Regulator of Translation). ChIP-chip analysis shows that under ethanol conditions, this factor binds to some gluconeogenic genes (e.g. PCK1), ribosomal proteins genes as well as genes encoding mitochondrial components and two genes encoding two subunits of the TFIIIC complex involved in RNA polymerase III transcription. There is also evidence that another zinc cluster protein, Gsm1, is also involved in controlling gene expression for adaptation to a non-fermentable carbon source. Clearly, regulation of gene expression following glucose exhaustion is a more complex process than initially anticipated. This proposal is aimed at better characterizing the role of the transcription factors Rds2, Ert1, Cat8, Sip4, and Gsm1. More specifically we will: 1) Determine the role of Ert1 with glucose or ethanol as carbon sources 2) Study the function of Gsm1 3) Determine the relative contribution and the interplay of Rds2, Ert1, Cat8, Sip4 and Gsm1 in mediating utilization of ethanol, lactate, glycerol, and acetate as carbon sources.

酿酒酵母优先使用葡萄糖作为碳源。葡萄糖耗尽后，这种酵母可以使用非糖碳（不可发酵碳），例如乙醇、乳酸盐和乙酸盐。这导致基因表达的大规模重编程以适应新的碳源。该过程由主激酶 Snf1 控制，该激酶磷酸化各种底物，包括转录因子 Cat8 和 Sip4，通过与目标基因启动子中发现的碳源响应元件结合来控制特定基因的表达。例如，这些因子上调 PCK1 的表达，PCK1 编码一种对糖异生非常重要的酶。 Cat8 和 Sip4 属于锌簇蛋白 Gal4 家族，形成酵母中一类重要的转录调节因子。我们通过对该因子进行全基因组定位（ChIP 芯片）来表征锌簇蛋白 Rds2，并发现它是糖异生的一个非常重要的调节因子。然而，Rds2 和 Cat8 显示出有限数量的共同靶基因。因此，它们具有特定和共同的功能。我们还描述了另一个锌簇基因，我们将其命名为 ERT1（乙醇翻译调节器）。 ChIP 芯片分析表明，在乙醇条件下，该因子与一些糖异生基因（例如 PCK1）、核糖体蛋白基因以及编码线粒体成分的基因和编码参与 RNA 聚合酶 III 转录的 TFIIIC 复合物两个亚基的两个基因结合。还有证据表明，另一种锌簇蛋白 Gsm1 也参与控制基因表达以适应不可发酵的碳源。显然，葡萄糖耗尽后基因表达的调节是一个比最初预期更复杂的过程。该提案旨在更好地表征转录因子 Rds2、Ert1、Cat8、Sip4 和 Gsm1 的作用。更具体地说，我们将： 1) 确定 Ert1 在葡萄糖或乙醇作为碳源时的作用 2) 研究 Gsm1 的功能 3) 确定 Rds2、Ert1、Cat8、Sip4 和 Gsm1 在介导乙醇、乳酸、甘油和乙酸盐作为碳源的利用中的相对贡献和相互作用。