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

2009 ◽  
Vol 29 (13) ◽  
pp. 3803-3815 ◽  
Author(s):  
Isabelle Georis ◽  
André Feller ◽  
Fabienne Vierendeels ◽  
Evelyne Dubois

ABSTRACT 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.

2000 ◽  
Vol 182 (23) ◽  
pp. 6584-6591 ◽  
Author(s):  
Thomas S. Cunningham ◽  
Rajendra Rai ◽  
Terrance G. Cooper

ABSTRACT Nitrogen-catabolic gene expression in Saccharomyces cerevisiae is regulated by the action of four GATA family transcription factors: Gln3p and Gat1p/Nil1p are transcriptional activators, and Dal80 and Deh1p/Gzf3p are repressors. In addition to the GATA sequences situated upstream of all nitrogen catabolite repression-sensitive genes that encode enzyme and transport proteins, the promoters of the GAT1, DAL80, andDEH1 genes all contain multiple GATA sequences as well. These GATA sequences are the binding sites of the GATA family transcription factors and are hypothesized to mediate their autogenous and cross regulation. Here we show, using DAL80 fused to the carbon-regulated GAL1,10 or copper-regulated CUP1 promoter, that GAT1expression is inversely regulated by the level of DAL80expression, i.e., as DAL80 expression increases,GAT1 expression decreases. The amount of DAL80expression also dictates the level at which DAL3, a gene activated almost exclusively by Gln3p, is transcribed. Gat1p was found to partially substitute for Gln3p in transcription. These data support the contention that regulation of GATA-factor gene expression is tightly and dynamically coupled. Finally, we suggest that the complicated regulatory circuit in which the GATA family transcription factors participate is probably most beneficial as cells make the transition from excess to limited nitrogen availability.


1999 ◽  
Vol 181 (8) ◽  
pp. 2472-2476 ◽  
Author(s):  
Alexander E. Beeser ◽  
Terrance G. Cooper

ABSTRACT Saccharomyces cerevisiae responds to nitrogen availability in several ways. (i) The cell is able to distinguish good nitrogen sources from poor ones through a process designated nitrogen catabolite repression (NCR). Good and poor nitrogen sources do not demonstrably affect the cell cycle other than to influence the cell’s doubling time. (ii) Nitrogen starvation promotes the initiation of sporulation and pseudohyphal growth. (iii) Nitrogen starvation strongly affects the cell cycle; nitrogen-starved cells arrest in G1. A specific allele of the SUP70/CDC65tRNAGln gene (sup70-65) has been reported to be defective in nitrogen signaling associated with pseudohyphal formation, sporulation, and NCR. Our data confirm that pseudohyphal growth occurs gratuitously in sup70-65 mutants cultured in nitrogen-rich medium at 30°C. However, we find neither any defect in NCR in thesup70-65 mutant nor any alteration in the control ofYVH1 expression, which has been previously shown to be specifically induced by nitrogen starvation.


Development ◽  
1998 ◽  
Vol 125 (24) ◽  
pp. 4909-4917 ◽  
Author(s):  
P. Bossard ◽  
K.S. Zaret

Gene inactivation studies have shown that members of the GATA family of transcription factors are critical for endoderm differentiation in mice, flies and worms, yet how these proteins function in such a conserved developmental context has not been understood. We use in vivo footprinting of mouse embryonic endoderm cells to show that a DNA-binding site for GATA factors is occupied on a liver-specific, transcriptional enhancer of the serum albumin gene. GATA site occupancy occurs in gut endoderm cells at their pluripotent stage: the cells have the potential to initiate tissue development but they have not yet been committed to express albumin or other tissue-specific genes. The GATA-4 isoform accounts for about half of the nuclear GATA-factor-binding activity in the endoderm. GATA site occupancy persists during hepatic development and is necessary for the activity of albumin gene enhancer. Thus, GATA factors in the endoderm are among the first to bind essential regulatory sites in chromatin. Binding occurs prior to activation of gene expression, changes in cell morphology or functional commitment that would indicate differentiation. We suggest that GATA factors at target sites in chromatin may generally help potentiate gene expression and tissue specification in metazoan endoderm development.


2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Marcos D. Palavecino ◽  
Susana R. Correa-García ◽  
Mariana Bermúdez-Moretti

Yeast can use a wide variety of nitrogen compounds. However, the ability to synthesize enzymes and permeases for catabolism of poor nitrogen sources is limited in the presence of a rich one. This general mechanism of transcriptional control is called nitrogen catabolite repression. Poor nitrogen sources, such as leucine, γ-aminobutyric acid (GABA), and allantoin, enable growth after the synthesis of pathway-specific catabolic enzymes and permeases. This synthesis occurs only under conditions of nitrogen limitation and in the presence of a pathway-specific signal. In this work we studied the temporal order in the induction of AGP1, BAP2, UGA4, and DAL7, genes that are involved in the catabolism and use of leucine, GABA, and allantoin, three poor nitrogen sources. We found that when these amino acids are available, cells will express AGP1 and BAP2 in the first place, then DAL7, and at last UGA4. Dal81, a general positive regulator of genes involved in nitrogen utilization related to the metabolisms of GABA, leucine, and allantoin, plays a central role in this coordinated regulation.


2013 ◽  
Vol 13 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Anna Andersson Rasmussen ◽  
Dineshkumar Kandasamy ◽  
Halfdan Beck ◽  
Seth D. Crosby ◽  
Olof Björnberg ◽  
...  

ABSTRACTPyrimidines are important nucleic acid precursors which are constantly synthesized, degraded, and rebuilt in the cell. Four degradation pathways, two of which are found in eukaryotes, have been described. One of them, theURCpathway, has been initially discovered in our laboratory in the yeastLachancea kluyveri. Here, we present the global changes in gene expression inL. kluyveriin response to different nitrogen sources, including uracil, uridine, dihydrouracil, and ammonia. The expression pattern of the knownURCgenes,URC1-6, helped to identify nine putative novelURCgenes with a similar expression pattern. The microarray analysis provided evidence that both theURCandPYDgenes are under nitrogen catabolite repression inL. kluyveriand are induced by uracil or dihydrouracil, respectively. We determined the function ofURC8, which was found to catalyze the reduction of malonate semialdehyde to 3-hydroxypropionate, the final degradation product of the pathway. The other eight genes studied were all putative permeases. Our analysis of double deletion strains showed that theL. kluyveriFui1p protein transported uridine, just like its homolog inSaccharomyces cerevisiae, but we demonstrated that is was not the only uridine transporter inL. kluyveri. We also showed that theL. kluyverihomologs ofDUR3andFUR4do not have the same function that they have inS. cerevisiae, where they transport urea and uracil, respectively. InL. kluyveri, both of these deletion strains grew normally on uracil and urea.


1984 ◽  
Vol 4 (5) ◽  
pp. 947-955 ◽  
Author(s):  
G Chisholm ◽  
T Cooper

We have isolated three cis-dominant mutations which dramatically enhance DUR1 ,2 gene expression in Saccharomyces cerevisiae. The mutant phenotype, which is expressed both in haploid and MATa/MAT alpha diploid strains, does not appear to be an alteration of the normal control system for this gene because its expression remained fully inducible and sensitive to nitrogen catabolite repression. Instead, we found much higher levels of DUR1 ,2-specific RNA under both uninduced and induced conditions, i.e., the overproduction trait was superimposed on normal regulation of the gene. The mutations seemed to affect gene expression in a unidirectional manner or to be specific for DUR1 ,2 gene expression, because other genes in proximity to the mutations were not affected. We feel that these mutations may alter the chromatin structure in the vicinity of the DUR1 ,2 upstream control sequences or, alternatively, may be Ty insertions which no longer possess the ROAM characteristics reported by others and ourselves.


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