The Yeast GATA Factor Gat1 Occupies a Central Position in Nitrogen Catabolite Repression-Sensitive Gene Activation

Institut de Recherches Microbiologiques J.-M. Wiame, Laboratoire de Microbiologie, Université Libre de Bruxelles, Av. E. Gryson 1, B-1070 Bruxelles, Belgium.
Molecular and Cellular Biology (Impact Factor: 4.78). 05/2009; 29(13):3803-15. DOI: 10.1128/MCB.00399-09
Source: PubMed


Saccharomyces cerevisiae cells are able to adapt their metabolism according to the quality of the nitrogen sources available in the environment. Nitrogen
catabolite repression (NCR) restrains the yeast's capacity to use poor nitrogen sources when rich ones are available. NCR-sensitive
expression is modulated by the synchronized action of four DNA-binding GATA factors. Although the first identified GATA factor,
Gln3, was considered the major activator of NCR-sensitive gene expression, our work positions Gat1 as a key factor for the
integrated control of NCR in yeast for the following reasons: (i) Gat1 appeared to be the limiting factor for NCR gene expression,
(ii) GAT1 expression was regulated by the four GATA factors in response to nitrogen availability, (iii) the two negative GATA factors
Dal80 and Gzf3 interfered with Gat1 binding to DNA, and (iv) Gln3 binding to some NCR promoters required Gat1. Our study also
provides mechanistic insights into the mode of action of the two negative GATA factors. Gzf3 interfered with Gat1 by nuclear
sequestration and by competition at its own promoter. Dal80-dependent repression of NCR-sensitive gene expression occurred
at three possible levels: Dal80 represses GAT1 expression, it competes with Gat1 for binding, and it directly represses NCR gene transcription.

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Available from: Isabelle Georis,
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    • "The mechanisms underlying this lack of correlation between growth and fermentation in some yeast species under some Nsource conditions need further investigation. Finally, it should be stressed that we in this work have only studied one strain within each of the five yeast species, and although we have found differences among species, we are fully aware that variability may also occur within yeast species ; i.e. among strains belonging to the same species, as already observed for S. cerevisiae (Georis et al. 2009; Godard et al. 2007; Gutiérrez et al. 2012; Magasanik and Kaiser 2002 "
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    ABSTRACT: In this study, the influence of twenty different single (i.e. 19 amino acids and ammonium sulphate) and two multiple nitrogen sources (N-sources) on growth and fermentation (i.e. glucose consumption and ethanol production) performance of Saccharomyces cerevisiae and of four wine-related non-Saccharomyces yeast species (Lachancea thermotolerans, Metschnikowia pulcherrima, Hanseniaspora uvarum and Torulaspora delbrueckii) was investigated during alcoholic fermentation. Briefly, the N-sources with beneficial effects on all performance parameters (or for the majority of them) for each yeast species were alanine, arginine, asparagine, aspartic acid, glutamine, isoleucine, ammonium sulphate, serine, valine and mixtures of 19 amino acids and of 19 amino acids plus ammonium sulphate (for S. cerevisiae), serine (for L. thermotolerans), alanine (for H. uvarum), alanine and asparagine (for M. pulcherrima), arginine, asparagine, glutamine, isoleucine and mixture of 19 amino acids (for T. delbrueckii). Furthermore, our results showed a clear positive effect of complex mixtures of N-sources on S. cerevisiae and on T. delbrueckii (although to a lesser extent) as to all performance parameters studied, whereas for L. thermotolerans, H. uvarum and M. pulcherrima, single amino acids affected growth and fermentation performance to the same extent as the mixtures. Moreover, we found groups of N-sources with similar effects on the growth and/or fermentation performance of two or more yeast species. Finally, the influences of N-sources observed for T. delbrueckii and H. uvarum resembled those of S. cerevisiae the most and the least, respectively. Overall, this work contributes to an improved understanding of how different N-sources affect growth, glucose consumption and ethanol production of wine-related yeast species under oxygen-limited conditions, which, in turn, may be used to, e.g. optimize growth and fermentation performance of the given yeast upon N-source supplementation during wine fermentations.
    Applied Microbiology and Biotechnology 08/2015; DOI:10.1007/s00253-015-6835-3 · 3.34 Impact Factor
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    • "The different subcellular fractions were analyzed by Western blotting with monoclonal antibodies for c-Myc (Santa Cruz Biotechnology), Pep12 (Invitrogen) and Pgk1 (Invitrogen, Carlsbad, CA). The electrophoresis, blotting, and detection procedures have been described previously (Georis et al. 2009). "
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    ABSTRACT: Nitrogen catabolite repression (NCR) is the regulatory pathway through which Saccharomyces cerevisiae responds to the available nitrogen status and selectively utilizes rich nitrogen sources in preference to poor ones. Expression of NCR-sensitive genes is mediated by two transcription activators, Gln3 and Gat1, in response to provision of a poorly used nitrogen source or following treatment with the TORC1 inhibitor, rapamycin. During nitrogen excess, the transcription activators are sequestered in the cytoplasm in a Ure2-dependent fashion. Here, we show that Vps components are required for Gln3 localization and function in response to rapamycin treatment when cells are grown in defined yeast nitrogen base but not in complex yeast peptone dextrose medium. On the other hand, Gat1 function was altered in vps mutants in all conditions tested. A significant fraction of Gat1, like Gln3, is associated with light intracellular membranes. Further, our results are consistent with the possibility that Ure2 might function downstream of the Vps components during the control of GATA factor-mediated gene expression. These observations demonstrate distinct media-dependent requirements of vesicular trafficking components for wild-type responses of GATA factor localization and function. As a result, the current model describing participation of Vps system components in events associated with translocation of Gln3 into the nucleus following rapamycin treatment or growth in nitrogen-poor medium requires modification.
    MicrobiologyOpen 06/2014; 3(3). DOI:10.1002/mbo3.168 · 2.21 Impact Factor
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    • "With the exception of Gln3 the expression of the transcription factors is also subjected to NCR control, such that without Gln3 no derepression of NCR genes can take place (Mitchell & Magasanik, 1984). Gat1-dependent activation of NCR depends on Gln3 activating Gat1 expression, whereas Gln3-dependent activation can promote transcription in the absence of the other transcription factors (Georis, et al., 2009). "
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    ABSTRACT: The yeast Saccharomyces cerevisiae has been a favorite organism for pioneering studies on nutrient-sensing and signaling mechanisms. Many specific nutrient responses have been elucidated in great detail. This has led to important new concepts and insight into nutrient-controlled cellular regulation. Major highlights include the central role of the Snf1 protein kinase in the glucose repression pathway, galactose induction, the discovery of a G-protein coupled receptor system and role of Ras in glucose-induced cAMP signaling, the role of the protein synthesis initiation machinery in general control of nitrogen metabolism, the cyclin-controlled protein kinase Pho85 in phosphate regulation, nitrogen catabolite repression and the nitrogen-sensing TOR pathway, and the discovery of transporter-like proteins acting as nutrient sensors. In addition, a number of cellular targets, like carbohydrate stores, stress tolerance and ribosomal gene expression, are controlled by the presence of multiple nutrients. The PKA signaling pathway plays a major role in this general nutrient response. It has led to the discovery of nutrient transceptors (transporter-receptors) as nutrient sensors. Major shortcomings in our knowledge are the relationship between rapid and steady-state nutrient signaling, the role of metabolic intermediates in intracellular nutrient sensing and the identity of the nutrient sensors controlling cellular growth. This article is protected by copyright. All rights reserved.
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