Ammonia assimilation in Saccharomyces cerevisiae as mediated by the two glutamate dehydrogenases

Grenson, Marcelle; Dubois, Evelyne; Piotrowska, Małgorzata; Drillien, Robert; Aigle, Michel

doi:10.1007/bf00267295

Cited by 111 publications

(48 citation statements)

References 17 publications

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“…Furthermore, substitution of a good nitrogen source with proline does not increase the expression of CM4IA1, indicating that ClA is not subject to nitrogen regulation (nitrogen catabolite derepression) (34). The gdhCR mutation is known to relieve NR (17), and on the basis of enzymatic measurements of CH41 expression in a gdhCR mutant it was suggested that CHA] is weakly affected by NR (two-to threefold derepression in a gdhCR mutant strain) (37). Here we addressed, by Northern analysis of C4A1 expression, the question of whether CH41 is subject to NR.…”

Section: Discussionmentioning

confidence: 99%

A regulatory element in the CHA1 promoter which confers inducibility by serine and threonine on Saccharomyces cerevisiae genes.

Bornaes¹,

Ignjatovic²,

Schjerling³

et al. 1993

Mol. Cell. Biol.

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CHAJ of Saccharomyces cerevisiae is the gene for the catabolic L-serine (L-threonine) dehydratase, which is responsible for biodegradation of serine and threonine. We have previously shown that expression of the CHiAI gene is transcriptionally induced by serine and threonine. Northern (RNA) analysis showed that the additional presence of good nitrogen sources affects induction. This may well be due to inducer exclusion. To identify interactions ofcis-acting elements with trans activators of the CA41 promoter, we performed band shift assays of nuclear protein extracts with CHA41 promoter fragments. By this approach, we identified a protein-binding site of the CIL41 promoter. The footprint of this protein contains the ABF1-binding site consensus sequence. This in vitro binding activity is present irrespectively of CIA41 induction. By deletion analysis, two other elements of the CL41 promoter, UASlcHA and UAS2CHA, which are needed for induction of the CHA1 gene were identified. Each of the two sequence elements is sufficient to confer serine and threonine induction upon the CYCI promoter when substituting its upstream activating sequence.

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Section: Discussionmentioning

confidence: 99%

A regulatory element in the CHA1 promoter which confers inducibility by serine and threonine on Saccharomyces cerevisiae genes.

Bornaes¹,

Ignjatovic²,

Schjerling³

et al. 1993

Mol. Cell. Biol.

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“…cerevisiae is the first microorganism described in which the NADP-GDH activity is encoded by two genes (6); the physiological significance of this apparent redundancy is not clear. When this yeast is grown on glucose and ammonium as carbon and nitrogen sources, Gdh1p is the primary pathway for glutamate biosynthesis (6,9,10). It has also been shown that GDH1 expression is regulated by the HAP system (11), which is known to control expression of genes involved in carbon metabolism and respiratory function (12).…”

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confidence: 99%

NADP-Glutamate Dehydrogenase Isoenzymes of Saccharomyces cerevisiae

DeLuna¹,

Avendaño

Riego

et al. 2001

Journal of Biological Chemistry

141

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In the yeast Saccharomyces cerevisiae, two NADP؉ -dependent glutamate dehydrogenases (NADP-GDHs) encoded by GDH1 and GDH3 catalyze the synthesis of glutamate from ammonium and ␣-ketoglutarate. The GDH2-encoded NAD ؉ -dependent glutamate dehydrogenase degrades glutamate producing ammonium and ␣-ketoglutarate. Until very recently, it was considered that only one biosynthetic NADP-GDH was present in S. cerevisiae. This fact hindered understanding the physiological role of each isoenzyme and the mechanisms involved in ␣-ketoglutarate channeling for glutamate biosynthesis. In this study, we purified and characterized the GDH1-and GDH3-encoded NADP-GDHs; they showed different allosteric properties and rates of ␣-ketoglutarate utilization. Analysis of the relative levels of these proteins revealed that the expression of GDH1 and GDH3 is differentially regulated and depends on the nature of the carbon source. Moreover, the physiological study of mutants lacking or overexpressing GDH1 or GDH3 suggested that these genes play nonredundant physiological roles. Our results indicate that the coordinated regulation of GDH1-, GDH3-, and GDH2-encoded enzymes results in glutamate biosynthesis and balanced utilization of ␣-ketoglutarate under fermentative and respiratory conditions. The possible relevance of the duplicated NADP-GDH pathway in the adaptation to facultative metabolism is discussed.

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“…In keeping with this physiological function, Gln3p supports transcriptional activation when tethered by LexAp upstream of a reporter gene devoid of UAS elements (25). Ure2p has been proposed to be a negative regulator of Gln3p function according to a model derived from (i) Lacroute's initial finding that a wild-type URE2 locus is required for ammonia repression (later referred to as NCR) (27,28,30), (ii) the demonstration that gln3 mutations are epistatic to ure2 mutations (21), and (iii) the finding that the Ure2p functions through UAS NTR (12). Dal80p has been proposed to be a DNA-binding protein that represses Gln3p-mediated transcription perhaps by competing with Gln3p for binding to some but not all GATAAG sequences (2,8,19,(22)(23)(24)26).…”

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confidence: 99%

Gat1p, a GATA Family Protein Whose Production Is Sensitive to Nitrogen Catabolite Repression, Participates in Transcriptional Activation of Nitrogen-Catabolic Genes in Saccharomyces cerevisiae

Coffman

Rai

Cunningham

et al. 1996

Molecular and Cellular Biology

132

208

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Saccharomyces cerevisiae cells selectively use nitrogen sources in their environment. Nitrogen catabolite repression (NCR) is the basis of this selectivity. Until recently NCR was thought to be accomplished exclusively through the negative regulation of Gln3p function by Ure2p. The demonstration that NCR-sensitive expression of multiple nitrogen-catabolic genes occurs in a gln3⌬ ure2⌬ dal80::hisG triple mutant indicated that the prevailing view of the nitrogen regulatory circuit was in need of revision; additional components clearly existed. Here we demonstrate that another positive regulator, designated Gat1p, participates in the transcription of NCR-sensitive genes and is able to weakly activate transcription when tethered upstream of a reporter gene devoid of upstream activation sequence elements. Expression of GAT1 is shown to be NCR sensitive, partially Gln3p dependent, and Dal80p regulated. In agreement with this pattern of regulation, we also demonstrate the existence of Gln3p and Dal80p binding sites upstream of GAT1.

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Ammonia assimilation in Saccharomyces cerevisiae as mediated by the two glutamate dehydrogenases

Cited by 111 publications

References 17 publications

A regulatory element in the CHA1 promoter which confers inducibility by serine and threonine on Saccharomyces cerevisiae genes.

A regulatory element in the CHA1 promoter which confers inducibility by serine and threonine on Saccharomyces cerevisiae genes.

NADP-Glutamate Dehydrogenase Isoenzymes of Saccharomyces cerevisiae

Gat1p, a GATA Family Protein Whose Production Is Sensitive to Nitrogen Catabolite Repression, Participates in Transcriptional Activation of Nitrogen-Catabolic Genes in Saccharomyces cerevisiae

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