scholarly journals Derepression of citrate synthase in Saccharomyces cerevisiae may occur at the level of transcription.

1984 ◽  
Vol 4 (2) ◽  
pp. 247-253 ◽  
Author(s):  
M A Hoosein ◽  
A S Lewin

Pulse-chase labeling in whole cells and cell-free protein synthesis were used to establish that the mitochondrial enzyme citrate synthase is made as a larger precursor in Saccharomyces cerevisiae. A 54,000 Mr precursor form appeared to be a primary translation product since it could be labeled with N-[35S]formylmethionine in vitro. The induction of citrate synthase was monitored in S. cerevisiae cells grown on fermentable (glucose) and nonfermentable (ethanol and glycerol) carbon sources. The amount of citrate synthase activity and immune-reactive protein increased more than 15-fold as S. cerevisiae cells entered the stationary growth phase on glucose-containing medium. This increase was paralleled by an increase in translatable RNA for the enzyme. When cells were grown on a nonfermentable carbon source, no increase in either citrate synthase or its mRNA was detected. The results suggest that the release of citrate synthase from catabolite repression may occur at the level of transcription.

1984 ◽  
Vol 4 (2) ◽  
pp. 247-253
Author(s):  
M A Hoosein ◽  
A S Lewin

Pulse-chase labeling in whole cells and cell-free protein synthesis were used to establish that the mitochondrial enzyme citrate synthase is made as a larger precursor in Saccharomyces cerevisiae. A 54,000 Mr precursor form appeared to be a primary translation product since it could be labeled with N-[35S]formylmethionine in vitro. The induction of citrate synthase was monitored in S. cerevisiae cells grown on fermentable (glucose) and nonfermentable (ethanol and glycerol) carbon sources. The amount of citrate synthase activity and immune-reactive protein increased more than 15-fold as S. cerevisiae cells entered the stationary growth phase on glucose-containing medium. This increase was paralleled by an increase in translatable RNA for the enzyme. When cells were grown on a nonfermentable carbon source, no increase in either citrate synthase or its mRNA was detected. The results suggest that the release of citrate synthase from catabolite repression may occur at the level of transcription.


1986 ◽  
Vol 6 (6) ◽  
pp. 1936-1942
Author(s):  
K S Kim ◽  
M S Rosenkrantz ◽  
L Guarente

The tricarboxylic acid cycle occurs within the mitochondria of the yeast Saccharomyces cerevisiae. A nuclear gene encoding the tricarboxylic acid cycle enzyme citrate synthase has previously been isolated (M. Suissa, K. Suda, and G. Schatz, EMBO J. 3:1773-1781, 1984) and is referred to here as CIT1. We report here the isolation, by an immunological method, of a second nuclear gene encoding citrate synthase (CIT2). Disruption of both genes in the yeast genome was necessary to produce classical citrate synthase-deficient phenotypes: glutamate auxotrophy and poor growth on rich medium containing lactate, a nonfermentable carbon source. Therefore, the citrate synthase produced from either gene was sufficient for these metabolic roles. Transcription of both genes was maximally repressed in medium containing both glucose and glutamate. However, transcription of CIT1 but not of CIT2 was derepressed in medium containing a nonfermentable carbon source. The significance of the presence of two genes encoding citrate synthase in S. cerevisiae is discussed.


1987 ◽  
Vol 7 (4) ◽  
pp. 1371-1377 ◽  
Author(s):  
T Toda ◽  
S Cameron ◽  
P Sass ◽  
M Zoller ◽  
J D Scott ◽  
...  

We have cloned a gene (BCY1) from the yeast Saccharomyces cerevisiae that encodes a regulatory subunit of the cyclic AMP-dependent protein kinase. The encoded protein has a structural organization similar to that of the RI and RII regulatory subunits of the mammalian cyclic AMP-dependent protein kinase. Strains of S. cerevisiae with disrupted BCY1 genes do not display a cyclic AMP-dependent protein kinase in vitro, fail to grow on many carbon sources, and are exquisitely sensitive to heat shock and starvation.


1987 ◽  
Vol 7 (7) ◽  
pp. 2344-2351
Author(s):  
R J Deschenes ◽  
J R Broach

Two proteins in the yeast Saccharomyces cerevisiae that are encoded by the genes RAS1 and RAS2 are structurally and functionally homologous to proteins of the mammalian ras oncogene family. We examined the role of fatty acylation in the maturation of yeast RAS2 protein by creating mutants in the putative palmitate addition site located at the carboxyl terminus of the protein. Two mutations, Cys-318 to an opal termination codon and Cys-319 to Ser-319, were created in vitro and substituted in the chromosome in place of the normal RAS2 allele. These changes resulted in a failure of RAS2 protein to be acylated with palmitate and a failure of RAS2 protein to be localized to a membrane fraction. The mutations yielded a Ras2- phenotype with respect to the ability of the resultant mutants to grow on nonfermentable carbon sources and to complement ras1- mutants. However, overexpression of the ras2Ser-319 product yielded a Ras+ phenotype without a corresponding association of the mutant protein with the membrane fraction. We conclude that the presence of a fatty acyl moiety is important for localizing RAS2 protein to the membrane where it is active but that the fatty acyl group is not an absolute requirement of RAS2 protein function.


1987 ◽  
Vol 7 (9) ◽  
pp. 3252-3259
Author(s):  
T Prezant ◽  
K Pfeifer ◽  
L Guarente

Regulation of the CYC7 gene of Saccharomyces cerevisiae, encoding iso-2-cytochrome c, was studied. Expression was induced about 20-fold by heme and derepressed 4- to 8-fold by a shift from glucose medium to one containing a nonfermentable carbon source. Deletion analysis showed that induction by heme depends upon sequences between -250 and -228 (from the coding sequence) and upon the HAP1 activator gene, previously shown to be required for CYC1 expression (L. Guarente et al., Cell 36:503-511, 1984). Thus, HAP1 coordinates expression of CYC7 and CYC1, the two genes encoding isologs of cytochrome c in S. cerevisiae. HAP1-18, a mutant allele of HAP1, which increased CYC7 expression more than 10-fold, also acted through sequences between -250 and -228. In vitro binding studies showed that the HAP1 product binds to these sequences (see also K. Pfeifer, T. Prezant, and L. Guarente, Cell 49:19-28, 1987) and an additional factor binds to distal sequences that lie between -201 and -165. This latter site augmented CYC7 expression in vivo. Derepression of CYC7 expression in a medium containing nonfermentable carbon sources depended upon sequences between -354 and -295. The interplay of these multiple sites and the factors that bind to them are discussed.


Biomolecules ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 198 ◽  
Author(s):  
Manoj K. Singh ◽  
Pradeep K. Rai ◽  
Anuradha Rai ◽  
Surendra Singh ◽  
Jay Shankar Singh

The production of poly-β-hydroxybutyrate (PHB) under varying environmental conditions (pH, temperature and carbon sources) was examined in the cyanobacterium Scytonema geitleri Bharadwaja isolated from the roof-top of a building. The S. geitleri produced PHB and the production of PHB was linear with the growth of cyanobacterium. The maximum PHB production (7.12% of dry cell weight) was recorded when the cells of S. geitleri were at their stationary growth phase. The production of PHB was optimum at pH 8.5 and 30 °C, and acetate (30 mM) was the preferred carbon source.


2014 ◽  
Vol 50 (3) ◽  
pp. 237-244 ◽  
Author(s):  
I. V. Fedoseeva ◽  
E. G. Rikhvanov ◽  
N. N. Varakina ◽  
T. M. Rusaleva ◽  
D. V. Pyatrikas ◽  
...  

2021 ◽  
Vol 14 (11) ◽  
pp. 1182
Author(s):  
Vladimir Vimberg ◽  
Leona Zieglerova ◽  
Aninda Mazumdar ◽  
Zsolt Szűcs ◽  
Aniko Borbás ◽  
...  

The increase in antibiotic resistance among Gram-positive bacteria underscores the urgent need to develop new antibiotics. New antibiotics should target actively growing susceptible bacteria that are resistant to clinically accepted antibiotics including bacteria that are not growing or are protected in a biofilm environment. In this paper, we compare the in vitro activities of two new semisynthetic glycopeptide antibiotics, MA79 and ERJ390, with two clinically used glycopeptide antibiotics—vancomycin and teicoplanin. The new antibiotics effectively killed not only exponentially growing cells of Staphylococcus aureus, but also cells in the stationary growth phase and biofilm.


1991 ◽  
Vol 11 (9) ◽  
pp. 4455-4465
Author(s):  
P W Coschigano ◽  
S M Miller ◽  
B Magasanik

We found that cells of Saccharomyces cerevisiae have an elevated level of the NAD-dependent glutamate dehydrogenase (NAD-GDH; encoded by the GDH2 gene) when grown with a nonfermentable carbon source or with limiting amounts of glucose, even in the presence of the repressing nitrogen source glutamine. This regulation was found to be transcriptional, and an upstream activation site (GDH2 UASc) sufficient for activation of transcription during respiratory growth conditions was identified. This UAS was found to be separable from a neighboring element which is necessary for the nitrogen source regulation of the gene, and strains deficient for the GLN3 gene product, required for expression of NAD-GDH during growth with the activating nitrogen source glutamate, were unaffected for the expression of NAD-GDH during growth with activating carbon sources. Two classes of mutations which prevented the normal activation of NAD-GDH in response to growth with nonfermentable carbon sources, but which did not affect the nitrogen-regulated expression of NAD-GDH, were found and characterized. Carbon regulation of GDH2 was found to be normal in hxk2, hap3, and hap4 strains and to be only slightly altered in a ssn6 strain; thus, in comparison with the regulation of previously identified glucose-repressed genes, a new pathway appears to be involved in the regulation of GDH2.


1992 ◽  
Vol 12 (9) ◽  
pp. 4197-4208
Author(s):  
S Silve ◽  
P R Rhode ◽  
B Coll ◽  
J Campbell ◽  
R O Poyton

Previously, we have shown that the Saccharomyces cerevisiae DNA-binding protein ABF1 exists in at least two different electrophoretic forms (K. S. Sweder, P. R. Rhode, and J. L. Campbell, J. Biol. Chem. 263: 17270-17277, 1988). In this report, we show that these forms represent different states of phosphorylation of ABF1 and that at least four different phosphorylation states can be resolved electrophoretically. The ratios of these states to one another differ according to growth conditions and carbon source. Phosphorylation of ABF1 is therefore a regulated process. In nitrogen-starved cells or in cells grown on nonfermentable carbon sources (e.g., lactate), phosphorylated forms predominate, while in cells grown on fermentable carbon sources (e.g., glucose), dephosphorylated forms are enriched. The phosphorylation pattern is affected by mutations in the SNF1-SSN6 pathway, which is involved in glucose repression-depression. Whereas a functional SNF1 gene, which encodes a protein kinase, is not required for the phosphorylation of ABF1, a functional SSN6 gene is required for itsd ephosphorylation. The phosphorylation patterns that we have observed correlate with the regulation of a specific target gene, COX6, which encodes subunit VI of cytochrome c oxidase. Transcription of COX6 is repressed by growth in medium containing a fermentable carbon source and is derepressed by growth in medium containing a nonfermentable carbon source. COX6 repression-derepression is under the control of the SNF1-SSN6 pathway. This carbon source regulation is exerted through domain 1, a region of the upstream activation sequence UAS6 that binds ABF1 (J. D. Trawick, N. Kraut, F. Simon, and R. O. Poyton, Mol. Cell Biol. 12:2302-2314, 1992). We show that the greater the phosphorylation of ABF1, the greater the transcription of COX6. Furthermore, the ABF1-containing protein-DNA complexes formed at domain 1 differ according to the phosphorylation state of ABF1 and the carbon source on which the cells were grown. From these findings, we propose that the phosphorylation of ABF1 is involved in glucose repression-derepression of COX6 transcription.


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