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Genetics. 2014 Oct;198(2):547-60. doi: 10.1534/genetics.114.168609. Epub 2014 Aug 13.

The switch from fermentation to respiration in Saccharomyces cerevisiae is regulated by the Ert1 transcriptional activator/repressor.

Author information

1
Department of Biochemistry, McGill University Health Centre, McGill University, Montreal, QC, Canada H3A 1A1.
2
Institut de recherches cliniques de Montréal, Montréal, QC, Canada H2W 1R7.
3
Department of Microbiology and Immunology, McGill University Health Centre, McGill University, Montreal, QC, Canada H3A 1A1.
4
Institut de recherches cliniques de Montréal, Montréal, QC, Canada H2W 1R7 Département de Médecine, Faculté de Médecine, Université de Montréal, QC, Canada H3C 3J7.
5
Department of Biochemistry, McGill University Health Centre, McGill University, Montreal, QC, Canada H3A 1A1 Department of Medicine, McGill University Health Centre, McGill University, Montreal, QC, Canada H3A 1A1 Department of Microbiology and Immunology, McGill University Health Centre, McGill University, Montreal, QC, Canada H3A 1A1 bernard.turcotte@mcgill.ca.

Abstract

In the yeast Saccharomyces cerevisiae, fermentation is the major pathway for energy production, even under aerobic conditions. However, when glucose becomes scarce, ethanol produced during fermentation is used as a carbon source, requiring a shift to respiration. This adaptation results in massive reprogramming of gene expression. Increased expression of genes for gluconeogenesis and the glyoxylate cycle is observed upon a shift to ethanol and, conversely, expression of some fermentation genes is reduced. The zinc cluster proteins Cat8, Sip4, and Rds2, as well as Adr1, have been shown to mediate this reprogramming of gene expression. In this study, we have characterized the gene YBR239C encoding a putative zinc cluster protein and it was named ERT1 (ethanol regulated transcription factor 1). ChIP-chip analysis showed that Ert1 binds to a limited number of targets in the presence of glucose. The strongest enrichment was observed at the promoter of PCK1 encoding an important gluconeogenic enzyme. With ethanol as the carbon source, enrichment was observed with many additional genes involved in gluconeogenesis and mitochondrial function. Use of lacZ reporters and quantitative RT-PCR analyses demonstrated that Ert1 regulates expression of its target genes in a manner that is highly redundant with other regulators of gluconeogenesis. Interestingly, in the presence of ethanol, Ert1 is a repressor of PDC1 encoding an important enzyme for fermentation. We also show that Ert1 binds directly to the PCK1 and PDC1 promoters. In summary, Ert1 is a novel factor involved in the regulation of gluconeogenesis as well as a key fermentation gene.

KEYWORDS:

Saccharomyces cerevisiae; fermentation; gluconeogenesis; transcriptional regulator; zinc cluster proteins

PMID:
25123508
PMCID:
PMC4196612
DOI:
10.1534/genetics.114.168609
[Indexed for MEDLINE]
Free PMC Article

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