Catabolite repression in yeasts is not associated with low levels of cAMP

Eraso, Pilar; Gancedo, Juana M.

doi:10.1111/j.1432-1033.1984.tb08174.x

Cited by 91 publications

(61 citation statements)

References 44 publications

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“…Surprisingly, these exponential cells on glucose (whether heat stressed or not) did not show any increase in neutral trehalase activity after phosphorylating the crude extract with an ATP/cAMP mixture (Table 1), in contrast to a 2 4 times increase in neutral trehalase activity in stationary cells grown on glucose or exponential cells grown on galactose [17]. We do not have a definite explanation for this, however, it could be related to the finding that c A M P levels of exponential cells growing on glucose are high when compared to stationary cells [25,26]. Furthermore, as shown in Table 1, we could not detect any significant acid trehalase activity either from heat stressed or non-heat stressed exponentially growing cells, thereby supporting our finding that the ATH1 gene is not involved in the recovery of cells after heat shock in contrast to the NTH1 and YBR0106 genes.…”

Section: Neutral and Acid Trehalase Activity At Heat Stresscontrasting

confidence: 41%

Phenotypic features of trehalase mutants in Saccharomyces cerevisiae

et al. 1995

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Section: Neutral and Acid Trehalase Activity At Heat Stresscontrasting

confidence: 41%

Phenotypic features of trehalase mutants in Saccharomyces cerevisiae

et al. 1995

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“…However several lines of evidence indicate that, in yeast, catabolite repression is not associated with a low level of CAMP. In a mutant permeable to CAMP, the addition of exogenous cAMP did not prevent glucose repression of galactokinase synthesis (Matsumoto et al, 1982) and in different yeasts intracellular concentrations of cAMP are higher in the presence of glucose and other sugars than in derepressed conditions (Eraso and Gancedo, 1984). Results from strains lacking adenylate cyclase suggest that, in S. certvisiae, cAMP itself does not play a critical role in catabolite repression (Matsumoto et al, 1983a) although cAMP may be necessary for the transcription of certain genes like SUC2 (Matsumoto et al, 1984).…”

Section: The Signalmentioning

confidence: 80%

“…The synthesis of this enzyme is also repressed by glucose (Eraso and Gancedo, 1984) and this repression appears to depend on the presence of a repressing nitrogen source like glutamine (Coschigano et al, 1991). The cyc8 mutation allows a partial derepression of GDH2 in the presence of glucose but neither HXK2 nor HAP3 or HAP4 appear to be involved in its regulation; other regulatory mutants which affect other systems subject to catabolite repression have not been tested.…”

Section: Nad-dependent Glutamate Dehydrogenasementioning

confidence: 99%

“…Catabolite repression can be exerted not only by the three related sugars glucose, mannose and fructose, but also by other types of sugars like galactose (Polakis and Bartley, 1965) or maltose (Eraso and Gancedo, 1984). The fact that some genes are repressed by all these sugars while others are only affected by glucose should be taken into account in any discussion about the signal involved in catabolite repression.…”

Section: The Signalmentioning

confidence: 99%

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Carbon catabolite repression in yeast

Gancedo

1992

European Journal of Biochemistry

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411

247

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Control of gene expression is a basic regulatory mechanism of living organisms. In microorganisms, glucose or other rapidly metabolizable carbon sources repress the expression of genes that code for enzymes related to the metabolism of other carbon sources. This phenomenon, known as catabolite repression, allows microorganisms to cope effectively with changes in the carbon sources present in their environment. In the case of Escherichiu coli, a model to explain at the molecular level the mechanism of catabolite repression has been worked out (Ullmann, 1985;Saier, 1989), although some of its elements remain unidentified.Yeasts are also subject to carbon catabolite repression but the underlying mechanism(s) is less understood than it is in E. coli and we do not yet know how glucose exerts its repressive effect. In the present article I will review information gathered in the last few years on a variety of catabolite-repressible systems, try to integrate it and to elaborate a scheme for carbon catabolite repression consistent with the results obtained. Although this review will be centered around Sacchuromyces cerevisiue, reference to other yeast species will be made when information is available.The degree of repression caused by glucose depends strongly on the enzyme affected and the strain used. As shown in Table 1, it can vary from about 800-fold for invertase to less than 10-fold for aconitase, cytochrome c oxidase or isocitrate dehydrogenase. In most cases, the decrease in enzyme levels caused by glucose is paralleled by a decrease in the concentration of the corresponding mRNA. This could be due to an effect of glucose either on the rate of transcription, or on the stability of the corresponding mRNA or on both.Direct measurements of transcription rates have been performed in only a few cases. For the genes CYCI, encoding iso-1 cytochrome c, and MAL6S, encoding maltase, it was found that derepressed cells synthesized the corresponding mRNAs 6 times and 15 times faster, respectively, than repressed cells (Zitomer et al., 1979;Federoff et al., 1983a). It should be noted that, in the case of maltase, an induction by maltose is superimposed on the process of catabolite repression, but even in the presence of maltose, the addition of glucose to a yeast culture causes an approximately I5-fold decrease in the rate of transcription of the MAL6S gene in Correspondence to J. M. Gancedo,

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“…Krug et al (2005) reported that the increased aconitase activity of cells grown on acetate is partially because of decreased repression by AcnR and that an additional transcriptional regulator (besides AcnR) or another regulatory mechanism for aconitase might exist. The only regulatory system that has ubiquitous effects on many different genes is catabolite derepression by cAMP receptor protein (Eraso & Gancedo, 1984;Kolb et al, 1993;. This regulator activates many genes in the presence of acetate.…”

Section: Discussionmentioning

confidence: 99%

Effect of carbon source availability and growth phase on expression of Corynebacterium glutamicum genes involved in the tricarboxylic acid cycle and glyoxylate bypass

2008

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The effect of different carbon sources on the expression of tricarboxylic acid (TCA) cycle genes, along with glyoxylate bypass genes, in Corynebacterium glutamicum was determined. All TCA cycle genes were coordinately expressed in medium containing acetate. Growth in the presence of acetate gave rise to abundant expression of most TCA cycle genes, with the level of gltA transcript being the highest. However, when the cells entered the stationary phase triggered by acetate exhaustion, all genes were repressed, except sucCD and mdhB, which were slightly induced. Acetate withdrawal from the growth medium during the exponential phase also led to rapid repression of most TCA cycle genes and a corresponding twofold increase in the expression of sucCD, which were strongly induced by citrate and succinate. In addition, glucose depletion during the stationary phase led to a corresponding 8-20-fold induction of the sucCD, aceA and aceB genes. Addition of glucose to acetate medium resulted in about 10-fold induction of sucCD. The strong dependence of TCA cycle sucCD and glyoxylate bypass aceA and aceB expression on carbon source availability was confirmed and the regulatory system will be studied precisely. INTRODUCTIONCorynebacterium glutamicum, a non-pathogenic, facultative anaerobic Gram-positive soil bacterium, is widely used in the industrial production of numerous metabolites, including amino acids and organic acids (Kinoshita et al., 1957;Liebl, 2005;Nishimura et al., 2007). In contrast to closely related, medically important pathogenic species, such as Corynebacterium diphtheriae and Mycobacterium tuberculosis, C. glutamicum is generally recognized as a nonhazardous organism (Dover et al., 2004;Funke et al., 1997). Furthermore, this organism has gained increasing interest as a suitable model organism for high-G+C-content Grampositive bacteria in general and for Corynebacterineae, a suborder of the Actinomycetes, in particular.One of the central metabolic pathways in C. glutamicum and in other aerobic bacteria is the tricarboxylic acid (TCA) cycle, which is responsible for the complete oxidation of acetyl-CoA derived from various substrates and for the provision of precursors for amino acid biosynthesis. TCA cycle intermediates are commonly used by other metabolic reactions in a wide variety of cell types. Due to the commercial importance of the amino acids and organic acids produced by C. glutamicum, the control of TCA cycle enzyme activities has been the subject of intensive studies, and the phenotypes of mutants affecting TCA cycle genes have been analysed (Eikmanns et al., 1994(Eikmanns et al., , 1995Molenaar et al., 1998Molenaar et al., , 2000Usuda et al., 1996;Wittmann & De Graaf, 2005). However, limited work has been devoted to the regulation of the expression of C. glutamicum TCA cycle genes in response to different growth phases and carbon sources. Recently we have reported the transcription of C. glutamicum genes involved in the TCA cycle and glyoxylate bypass (Han et al., 2008). In fact, aspects of the re...

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Catabolite repression in yeasts is not associated with low levels of cAMP

Cited by 91 publications

References 44 publications

Phenotypic features of trehalase mutants in Saccharomyces cerevisiae

Phenotypic features of trehalase mutants in Saccharomyces cerevisiae

Carbon catabolite repression in yeast

Effect of carbon source availability and growth phase on expression of Corynebacterium glutamicum genes involved in the tricarboxylic acid cycle and glyoxylate bypass

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