Journal articles: 'Acetate repression'

1

Toyoda, Koichi, Haruhiko Teramoto, Masayuki Inui, and Hideaki Yukawa. "The ldhA Gene, Encoding Fermentative l-Lactate Dehydrogenase of Corynebacterium glutamicum, Is under the Control of Positive Feedback Regulation Mediated by LldR." Journal of Bacteriology 191, no. 13 (May 1, 2009): 4251–58. http://dx.doi.org/10.1128/jb.00303-09.

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ABSTRACT Corynebacterium glutamicum ldhA encodes l-lactate dehydrogenase, a key enzyme that couples l-lactate production to reoxidation of NADH formed during glycolysis. We previously showed that in the absence of sugar, SugR binds to the ldhA promoter region, thereby repressing ldhA expression. In this study we show that LldR is another protein that binds to the ldhA promoter region, thus regulating ldhA expression. LldR has hitherto been characterized as an l-lactate-responsive transcriptional repressor of l-lactate utilization genes. Transposon mutagenesis of a reporter strain carrying a chromosomal ldhA promoter-lacZ fusion (PldhA-lacZ) revealed that ldhA disruption drastically decreased expression of PldhA-lacZ. PldhA-lacZ expression in the ldhA mutant was restored by deletion of lldR, suggesting that LldR acts as a repressor of ldhA in the absence of l-lactate and the LldR-mediated repression is not relieved in the ldhA mutant due to its inability to produce l-lactate. lldR deletion did not affect PldhA-lacZ expression in the wild-type background during growth on either glucose, acetate, or l-lactate. However, it upregulated PldhA-lacZ expression in the sugR mutant background during growth on acetate. The binding sites of LldR and SugR are located around the −35 and −10 regions of the ldhA promoter, respectively. C. glutamicum ldhA expression is therefore primarily repressed by SugR in the absence of sugar. In the presence of sugar, SugR-mediated repression of ldhA is alleviated, and ldhA expression is additionally enhanced by LldR inactivation in response to l-lactate produced by LdhA.

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Lesley, Joseph A., and Carey D. Waldburger. "Repression of Escherichia coli PhoP-PhoQ Signaling by Acetate Reveals a Regulatory Role for Acetyl Coenzyme A." Journal of Bacteriology 185, no. 8 (April 15, 2003): 2563–70. http://dx.doi.org/10.1128/jb.185.8.2563-2570.2003.

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ABSTRACT The PhoP-PhoQ two-component system regulates the transcription of numerous genes in response to changes in extracellular divalent cation concentration and pH. Here we demonstrate that the Escherichia coli PhoP-PhoQ two-component system also responds to acetate. Signaling by the E. coli PhoP-PhoQ system was repressed during growth in acetate (≥25 mM) in a PhoQ-dependent manner. The periplasmic sensor domain of PhoQ was not required for acetate to repress signaling. Acetate-mediated repression of the PhoP-PhoQ system was not related to changes in the intracellular concentration of acetate metabolites such as acetyl-phosphate or acetyladenylate. Genetic analysis of acetate metabolism pathways suggested that a perturbation of acetyl coenzyme A turnover was the cause of decreased PhoP-PhoQ signaling during growth in acetate. Consistent with this hypothesis, intracellular acetyl coenzyme A levels rose during growth in the presence of exogenous acetate. Acetyl coenzyme A inhibited the autokinase activity of PhoQ in vitro, suggesting that the in vivo repressing effect may be due to a direct inhibition mechanism.

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Shenhar, Galit, and Yona Kassir. "A Positive Regulator of Mitosis, Sok2, Functions as a Negative Regulator of Meiosis in Saccharomyces cerevisiae." Molecular and Cellular Biology 21, no. 5 (March 1, 2001): 1603–12. http://dx.doi.org/10.1128/mcb.21.5.1603-1612.2001.

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ABSTRACT The choice between meiosis and alternative developmental pathways in budding yeast depends on the expression and activity of transcriptional activator Ime1. The transcription of IME1is repressed in the presence of glucose, and a low basal level ofIME1 RNA is observed in vegetative cultures with acetate as the sole carbon source. IREu, a 32-bp element in the IME1promoter, exhibits upstream activation sequence activity depending on Msn2 and -4 and the presence of acetate. We show that in the presence of glucose IREu functions as a negative element and that Sok2 mediates this repression activity. We show that Sok2 associates with Msn2. Sok2 functions as a general repressor whose availability and activity depend on glucose. The activity of Sok2 as a repressor depends on phosphorylation of T598 by protein kinase A (PKA). Relief of repression of Sok2 depends on both the N-terminal domain of Sok2 and Ime1. In the absence of glucose and the presence of Ime1 Sok2 is converted to a weak activator. Overexpression of Sok2 or mild expression of Sok2 with its N-terminal domain deleted leads to a decrease in sporulation. Previously it was reported that overexpression of Sok2 suppresses the growth defect resulting from a temperature-sensitive PKA; thus Sok2 has a positive role in mitosis. We show that Candida albicansEfg1, a homolog of Sok2, complements sok2Δ in repressing IREu. Our results demonstrate that Sok2, a positive regulator of mitosis, and Efg1, a positive regulator of filamentation, function as negative regulators of meiosis. We suggest that cells use the same regulators with opposing effects to ensure that meiosis will be an alternative to mitosis.

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Georgakopoulos, Paraskevi, Robin A. Lockington, and Joan M. Kelly. "SAGA Complex Components and Acetate Repression inAspergillus nidulans." G3: Genes|Genomes|Genetics 2, no. 11 (November 2012): 1357–67. http://dx.doi.org/10.1534/g3.112.003913.

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Ahmed, Hamid K., Wilfrid J. Mitchell, and Fergus G. Priest. "Catabolite repression of histidase biosynthesis inBacillus sphaericusby acetate." FEMS Microbiology Letters 106, no. 1 (January 1993): 71–75. http://dx.doi.org/10.1111/j.1574-6968.1993.tb05937.x.

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6

Kumari, Suman, Christine M. Beatty, Douglas F. Browning, Stephen J. W. Busby, Erica J. Simel, Galadriel Hovel-Miner, and Alan J. Wolfe. "Regulation of Acetyl Coenzyme A Synthetase inEscherichia coli." Journal of Bacteriology 182, no. 15 (August 1, 2000): 4173–79. http://dx.doi.org/10.1128/jb.182.15.4173-4179.2000.

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ABSTRACT Cells of Escherichia coli growing on sugars that result in catabolite repression or amino acids that feed into glycolysis undergo a metabolic switch associated with the production and utilization of acetate. As they divide exponentially, these cells excrete acetate via the phosphotransacetylase-acetate kinase pathway. As they begin the transition to stationary phase, they instead resorb acetate, activate it to acetyl coenzyme A (acetyl-CoA) by means of the enzyme acetyl-CoA synthetase (Acs) and utilize it to generate energy and biosynthetic components via the tricarboxylic acid cycle and the glyoxylate shunt, respectively. Here, we present evidence that this switch occurs primarily through the induction of acs and that the timing and magnitude of this induction depend, in part, on the direct action of the carbon regulator cyclic AMP receptor protein (CRP) and the oxygen regulator FNR. It also depends, probably indirectly, upon the glyoxylate shunt repressor IclR, its activator FadR, and many enzymes involved in acetate metabolism. On the basis of these results, we propose that cells induce acs, and thus their ability to assimilate acetate, in response to rising cyclic AMP levels, falling oxygen partial pressure, and the flux of carbon through acetate-associated pathways.

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Rahman, M. Tanvir, Andrew Crombie, Hélène Moussard, Yin Chen, and J. Colin Murrell. "Acetate Repression of Methane Oxidation by Supplemental Methylocella silvestris in a Peat Soil Microcosm." Applied and Environmental Microbiology 77, no. 12 (April 22, 2011): 4234–36. http://dx.doi.org/10.1128/aem.02902-10.

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ABSTRACTMethylocellaspp. are facultative methanotrophs that grow on methane and multicarbon substrates, such as acetate. Acetate represses transcription of methane monooxygenase ofMethylocella silvestrisin laboratory culture. DNA stable-isotope probing (DNA-SIP) using13C-methane and12C-acetate, carried out withMethylocella-spiked peat soil, showed that acetate also repressed methane oxidation byMethylocellain environmental samples.

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8

Campbell III, John, Gary R. Bender, and Robert E. Marquis. "Barotolerant variant of Streptococcus faecalis with reduced sensitivity to glucose catabolite repression." Canadian Journal of Microbiology 31, no. 7 (July 1, 1985): 644–50. http://dx.doi.org/10.1139/m85-121.

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Physiological characterization of the APR-11 variant of Streptococcus faecalis ATCC 9790 revealed that the variant has reduced sensitivity to glucose catabolite repression. This reduced sensitivity was indicated by the synthesis of enzymes for catabolism of lactose or arginine in cultures growing at 0.1, 40, or 70 MPa in media with levels of glucose highly repressive for the parent strain. Reduced catabolite repression appeared to be due to reduced activity of the glucose-specific, phosphotransferase system in APR-11 cells. Conversion of pyruvate to lactate or to acetate and ethanol did not appear to be altered in the variant. The APR-11 variant produced a greater final yield of biomass than the parent at all pressures tested, and its barotolerance was especially marked in media with low levels of glucose and high levels of lactose in which derepression of the lactose catabolic system was necessary for full growth. Overall, the greater barotolerance of the APR-11 strain appeared to be due to its enhanced capacity for catabolism related to its reduced sensitivity to catabolite repression by glucose.

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9

Ampe, Frédéric, David Léonard, and Nicholas D. Lindley. "Repression of Phenol Catabolism by Organic Acids in Ralstonia eutropha." Applied and Environmental Microbiology 64, no. 1 (January 1, 1998): 1–6. http://dx.doi.org/10.1128/aem.64.1.1-6.1998.

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ABSTRACT During batch growth of Ralstonia eutropha (previously named Alcaligenes eutrophus) on phenol in the presence of acetate, acetate was found to be the preferred substrate; this organic acid was rapidly metabolized, and the specific rate of phenol consumption was considerably decreased, although phenol consumption was not abolished. This decrease corresponded to a drop in phenol hydroxylase and catechol-2,3-dioxygenase specific activities, and the synthesis of the latter was repressed at the transcriptional level. Studies with a mutant not able to consume acetate indicated that the organic acid itself triggers the repression. Other organic acids were also found to repress phenol degradation. One of these, benzoate, was found to completely block the catabolism of phenol (diauxic growth). A mutant unable to metabolize benzoate was also unable to develop on benzoate-phenol mixtures, indicating that the organic acid rather than a metabolite involved in benzoate degradation was responsible for the repression observed.

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10

Haas, MJ, D. Reinacher, JP Li, NC Wong, and AD Mooradian. "Regulation of apoA1 gene expression with acidosis: requirement for a transcriptional repressor." Journal of Molecular Endocrinology 27, no. 1 (August 1, 2001): 43–57. http://dx.doi.org/10.1677/jme.0.0270043.

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Serum apolipoprotein A(1) (apoA(1)) concentration is inversely correlated with the risk of premature atherosclerosis. Serum apoA(1) concentrations are regulated, in part, at the transcriptional level. ApoA(1) mRNA is synthesized primarily in the liver and small intestine, under the direction of a number of signaling molecules and tissue-specific regulatory elements. Previously, we demonstrated that extracellular acidosis suppresses apoA(1) mRNA levels at the level of transcription. Here we demonstrate that intracellular acidosis, in the absence of extracellular pH changes, represses apoA(1) promoter activity. Repression occurs through a pH responsive element (pH-RE) located within the apoA(1) gene promoter. Acidosis increases the specific DNA binding activity of a putative repressor protein within the immediate 5'-flanking region of the apoA(1) gene. The cis-element that binds the putative repressor protein contains a negative thyroid hormone response element (nTRE) located 3' and adjacent to the apoA(1) TATA box. Mutation of the nTRE/pH-RE abrogates protein binding and alters the activity of reporter genes controlled by this element. Repression by acidosis did not require de novo mRNA and protein synthesis. Inhibition of tyrosine kinase activity and diacylglycerol-stimulated protein kinase C (PKC) signaling pathways with tyrophostin A47 and phorbol myristate acetate, respectively, did not affect the repression of apoA(1) promoter activity with acidosis. These results suggest that transcriptional repression of the apoA(1) gene by alterations in ambient pH is associated with enhanced DNA binding activity of a repressor protein, through a mechanism which appears to be independent of de novo mRNA and protein synthesis, tyrosine kinase activity, or PKC activation.

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11

Arndt, Annette, and Bernhard J. Eikmanns. "The Alcohol Dehydrogenase Gene adhA in Corynebacterium glutamicum Is Subject to Carbon Catabolite Repression." Journal of Bacteriology 189, no. 20 (August 10, 2007): 7408–16. http://dx.doi.org/10.1128/jb.00791-07.

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ABSTRACT Corynebacterium glutamicum has recently been shown to grow on ethanol as a carbon and energy source and to possess high alcohol dehydrogenase (ADH) activity when growing on this substrate and low ADH activity when growing on ethanol plus glucose or glucose alone. Here we identify the C. glutamicum ADH gene (adhA), analyze its transcriptional organization, and investigate the relevance of the transcriptional regulators of acetate metabolism RamA and RamB for adhA expression. Sequence analysis of adhA predicts a polypeptide of 345 amino acids showing up to 57% identity with zinc-dependent ADH enzymes of group I. Inactivation of the chromosomal adhA gene led to the inability to grow on ethanol and to the absence of ADH activity, indicating that only a single ethanol-oxidizing ADH enzyme is present in C. glutamicum. Transcriptional analysis revealed that the C. glutamicum adhA gene is monocistronic and that its expression is repressed in the presence of glucose and of acetate in the growth medium, i.e., that adhA expression is subject to catabolite repression. Further analyses revealed that RamA and RamB directly bind to the adhA promoter region, that RamA is essential for the expression of adhA, and that RamB exerts a negative control on adhA expression in the presence of glucose or acetate in the growth medium. However, since the glucose- and acetate-dependent down-regulation of adhA expression was only partially released in a RamB-deficient mutant, there might be an additional regulator involved in the catabolite repression of adhA.

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12

Yamagata, T., J. Nishida, S. Tanaka, R. Sakai, K. Mitani, M. Yoshida, T. Taniguchi, Y. Yazaki, and H. Hirai. "A novel interferon regulatory factor family transcription factor, ICSAT/Pip/LSIRF, that negatively regulates the activity of interferon-regulated genes." Molecular and Cellular Biology 16, no. 4 (April 1996): 1283–94. http://dx.doi.org/10.1128/mcb.16.4.1283.

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We have isolated a novel cDNA clone encoding interferon (IFN) consensus sequence-binding protein in adult T-cell leukemia cell line or activated T cells (ICSAT); this protein is the human homolog of the recently cloned Pip/LSIRF. ICSAT is structurally most closely related to the previously cloned ICSBP, a member of the IFN regulatory factor (IRF) family of proteins that binds to interferon consensus sequences (ICSs) found in many promoters of the IFN-regulated genes. Among T-cell lines investigated, ICSAT was abundantly expressed in human T-cell leukemia virus type 1 (HTLV-1)-infected T cells. When the HTLV-1 tax gene was expressed or phorbol myristake acetate-A23187 stimulation was used, ICSAT expression was induced in Jurkat cells which otherwise do not express ICSAT. When the binding of ICSAT to four different ICSs was tested, the relative differences in binding affinities for those ICSs were determined. To study the functional role of ICSAT, we performed cotransfection experiments with the human embryonal carcinoma cell line N-Tera2. ICSAT was demonstrated to possess repressive function over the gene activation induced by IFN stimulation or by IRF-1 cotransfection. Such repressive function is similar to that seen in IRF-2 or ICSBP. However, we have found that ICSAT has a different repressive effect from that of IRF-2 or ICSBP in some IFN-responsive reporter constructs. These results suggest that a novel mechanism of gene regulation by "differential repression" is used by multiple members of repressor proteins with different repressive effects on the IFN-responsive genes.

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13

Katz, M. E., and M. J. Hynes. "Isolation and analysis of the acetate regulatory gene, facB, from Aspergillus nidulans." Molecular and Cellular Biology 9, no. 12 (December 1989): 5696–701. http://dx.doi.org/10.1128/mcb.9.12.5696-5701.1989.

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The facB gene of Aspergillus nidulans is thought to be involved in acetate induction of enzymes required for acetate utilization and of the acetamidase encoded by the multiply regulated amdS gene. In addition, some evidence suggests that the facB gene has a structural as well as a regulatory role in acetate metabolism. The facB gene was cloned from a cosmid library by complementation of the facB101 loss-of-function mutation. Transformants receiving multiple copies of facB displayed stronger growth on acetamide media, indicating increased amdS expression, while growth on acetate was inhibited in these multicopy transformants. A 3.1-kilobase acetate-inducible facB transcript was detected by Northern (RNA) blot analysis. Examination of message levels in wild-type and mutant strains indicated that the facB gene is subject to carbon catabolite repression. Previous work has indicated that the presence of multiple copies of the 5' end of the amdS gene can result in titration of regulatory proteins. Additional copies of the facB gene were shown to specifically overcome the effect of facB product titration.

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Katz, M. E., and M. J. Hynes. "Isolation and analysis of the acetate regulatory gene, facB, from Aspergillus nidulans." Molecular and Cellular Biology 9, no. 12 (December 1989): 5696–701. http://dx.doi.org/10.1128/mcb.9.12.5696.

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The facB gene of Aspergillus nidulans is thought to be involved in acetate induction of enzymes required for acetate utilization and of the acetamidase encoded by the multiply regulated amdS gene. In addition, some evidence suggests that the facB gene has a structural as well as a regulatory role in acetate metabolism. The facB gene was cloned from a cosmid library by complementation of the facB101 loss-of-function mutation. Transformants receiving multiple copies of facB displayed stronger growth on acetamide media, indicating increased amdS expression, while growth on acetate was inhibited in these multicopy transformants. A 3.1-kilobase acetate-inducible facB transcript was detected by Northern (RNA) blot analysis. Examination of message levels in wild-type and mutant strains indicated that the facB gene is subject to carbon catabolite repression. Previous work has indicated that the presence of multiple copies of the 5' end of the amdS gene can result in titration of regulatory proteins. Additional copies of the facB gene were shown to specifically overcome the effect of facB product titration.

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15

Turinsky, Andrew J., Tessa R. Moir-Blais, Frank J. Grundy, and Tina M. Henkin. "Bacillus subtilis ccpA Gene Mutants Specifically Defective in Activation of Acetoin Biosynthesis." Journal of Bacteriology 182, no. 19 (October 1, 2000): 5611–14. http://dx.doi.org/10.1128/jb.182.19.5611-5614.2000.

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ABSTRACT A large number of carbon source utilization pathways are repressed in Bacillus subtilis by the global regulator CcpA, which also acts as an activator of carbon excretion pathways during growth in media containing glucose. In this study, CcpA mutants defective in transcriptional activation of the alsSD operon, which is involved in acetoin biosynthesis, were identified. These mutants retained normal glucose repression of amyE, encoding α-amylase, and acsA, encoding acetyl-coenzyme A synthetase, and normal activation of ackA, which is involved in acetate excretion; in these ccpA mutants the CcpA functions of activation of the acetate and acetoin excretion pathways appear to be separated.

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16

Sugarman, J. L., A. H. Schönthal, and C. K. Glass. "Identification of a cell-type-specific and E2F-independent mechanism for repression of cdc2 transcription." Molecular and Cellular Biology 15, no. 6 (June 1995): 3282–90. http://dx.doi.org/10.1128/mcb.15.6.3282.

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Human myeloid leukemia cells, such as HL60, U937, and THP1 cells, undergo macrophage differentiation and growth arrest following treatment with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Surprisingly, we find that growth of a significant percentage of THP1 cells is arrested in the G2 phase of the cell cycle. G2 arrest correlates with cell-specific repression of the gene encoding p34cdc2, a crucial regulator of G2/M progression. Intriguingly, TPA-mediated repression of the cdc2 promoter was independent of the transcription factor E2F, distinguishing this pathway from mechanisms responsible for repression of cdc2 transcription in response to serum starvation. The region of the cdc2 promoter required for repression was located from bp -22 to -2 from the major transcriptional start site. This sequence, which we term the R box, directs the uncoupling of the basal promoter from upstream activators following TPA treatment. Analysis of THP1 nuclear proteins revealed a 55-kDa protein that was induced by TPA and interacted with the cdc2 promoter in an R-box-dependent manner. These observations provide evidence for the existence of cell-type- and promoter-specific pathways for the assembly of stable transcriptional initiation complexes that function to differentially regulate the expression of cell cycle control genes in mammalian cells.

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17

Zimmermann, Tina, Tobias Sorg, Simone Yasmin Siehler, and Ulrike Gerischer. "Role of Acinetobacter baylyi Crc in Catabolite Repression of Enzymes for Aromatic Compound Catabolism." Journal of Bacteriology 191, no. 8 (February 6, 2009): 2834–42. http://dx.doi.org/10.1128/jb.00817-08.

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ABSTRACT Here, we describe for the first time the Crc (catabolite repression control) protein from the soil bacterium Acinetobacter baylyi. Expression of A. baylyi crc varied according to the growth conditions. A strain with a disrupted crc gene showed the same growth as the wild type on a number of carbon sources. Carbon catabolite repression by acetate and succinate of protocatechuate 3,4-dioxygenase, the key enzyme of protocatechuate breakdown, was strongly reduced in the crc strain, whereas in the wild-type strain it underwent strong catabolite repression. This strong effect was not based on transcriptional regulation because the transcription pattern of the pca-qui operon (encoding protocatechuate 3,4-dioxygenase) did not reflect the derepression in the absence of Crc. pca-qui transcript abundance was slightly increased in the crc strain. Lack of Crc dramatically increased the mRNA stability of the pca-qui transcript (up to 14-fold), whereas two other transcripts (pobA and catA) remained unaffected. p-Hydroxybenzoate hydroxylase activity, encoded by pobA, was not significantly different in the absence of Crc, as protocatechuate 3,4-dioxygenase was. It is proposed that A. baylyi Crc is involved in the determination of the transcript stability of the pca-qui operon and thereby effects catabolite repression.

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18

Rivière, Loïc, Susanne W. H. van Weelden, Patricia Glass, Patricia Vegh, Virginie Coustou, Marc Biran, Jaap J. van Hellemond, Frédéric Bringaud, Aloysius G. M. Tielens, and Michael Boshart. "Acetyl:Succinate CoA-transferase in ProcyclicTrypanosoma brucei." Journal of Biological Chemistry 279, no. 44 (August 23, 2004): 45337–46. http://dx.doi.org/10.1074/jbc.m407513200.

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Acetyl:succinate CoA-transferase (ASCT) is an acetate-producing enzyme shared by hydrogenosomes, mitochondria of trypanosomatids, and anaerobically functioning mitochondria. The gene encoding ASCT in the protozoan parasiteTrypanosoma bruceiwas identified as a new member of the CoA transferase family. Its assignment to ASCT activity was confirmed by 1) a quantitative correlation of protein expression and activity upon RNA interference-mediated repression, 2) the absence of activity in homozygous Δasct/Δasctknock out cells, 3) mitochondrial colocalization of protein and activity, 4) increased activity and acetate excretion upon transgenic overexpression, and 5) depletion of ASCT activity from lysates upon immunoprecipitation. Genetic ablation of ASCT produced a severe growth phenotype, increased glucose consumption, and excretion of β-hydroxybutyrate and pyruvate, indicating accumulation of acetyl-CoA. Analysis of the excreted end products of13C-enriched and14C-labeled glucose metabolism showed that acetate excretion was only slightly reduced. Adaptation to ASCT deficiency, however, was an infrequent event at the population level, indicating the importance of this enzyme. These studies show that ASCT is indeed involved in acetate production, but is not essential, as apparently it is not the only enzyme that produces acetate inT. brucei.

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Stemple, Christopher J., Meryl A. Davis, and Michael J. Hynes. "The facC Gene of Aspergillus nidulans Encodes an Acetate-Inducible Carnitine Acetyltransferase." Journal of Bacteriology 180, no. 23 (December 1, 1998): 6242–51. http://dx.doi.org/10.1128/jb.180.23.6242-6251.1998.

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ABSTRACT Mutations in the facC gene of Aspergillus nidulans result in an inability to use acetate as a sole carbon source. This gene has been cloned by complementation. The proposed translation product of the facC gene has significant similarity to carnitine acetyltransferases (CAT) from other organisms. Total CAT activity was found to be inducible by acetate and fatty acids and repressed by glucose. Acetate-inducible activity was found to be absent in facC mutants, while fatty acid-inducible activity was absent in an acuJ mutant. Acetate induction offacC expression was dependent on the facBregulatory gene, and an expressed FacB fusion protein was demonstrated to bind to 5′ facC sequences. Carbon catabolite repression of facC expression was affected by mutations in thecreA gene and a CreA fusion protein bound to 5′facC sequences. Mutations in the acuJ gene led to increased acetate induction of facC expression and also of an amdS-lacZ reporter gene, and it is proposed that this results from accumulation of acetate, as well as increased expression of facB. A model is presented in which facCencodes a cytosolic CAT enzyme, while a different CAT enzyme, which isacuJ dependent, is present in peroxisomes and mitochondria, and these activities are required for the movement of acetyl groups between intracellular compartments.

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20

Liptay, S., R. M. Schmid, E. G. Nabel, and G. J. Nabel. "Transcriptional regulation of NF-kappa B2: evidence for kappa B-mediated positive and negative autoregulation." Molecular and Cellular Biology 14, no. 12 (December 1994): 7695–703. http://dx.doi.org/10.1128/mcb.14.12.7695-7703.1994.

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NF-kappa B is an inducible transcription factor complex which regulates the expression of a variety of genes which are involved in the immune, inflammatory, and acute-phase responses. The maintenance of NF-kappa B activity in stimulated cells requires ongoing protein synthesis, suggesting several modes of regulation. In this report, we have characterized the transcriptional regulation of one family member, NF-kappa B2. The genomic structure and sequence of NF-kappa B2 revealed the presence of two promoters and at least four kappa B regulatory elements, which mediate responsiveness to phorbol myristate acetate and tumor necrosis factor alpha. Similar to other NF-kappa B family members, NF-kappa B2 is positively autoregulated. In contrast to other family members, we find that kappa B elements in the NFKB2 promoter can also mediate transcriptional repression in the absence of NF-kappa B. We identified a nuclear complex which binds specifically to a subset of kappa B-related sites but not to the canonical kappa B element. Because of its putative inhibitory or repressive effect, this binding activity has been termed Rep-kappa B. This mechanism of repressing basal NF-kappa B2 transcription in an inactivated state enables the cell to tightly control NF-kappa B2 activity. These data demonstrate that a novel mode of kappa B-dependent regulation is mediated by specific kappa B sites in the NFKB2 promoter.

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Liptay, S., R. M. Schmid, E. G. Nabel, and G. J. Nabel. "Transcriptional regulation of NF-kappa B2: evidence for kappa B-mediated positive and negative autoregulation." Molecular and Cellular Biology 14, no. 12 (December 1994): 7695–703. http://dx.doi.org/10.1128/mcb.14.12.7695.

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NF-kappa B is an inducible transcription factor complex which regulates the expression of a variety of genes which are involved in the immune, inflammatory, and acute-phase responses. The maintenance of NF-kappa B activity in stimulated cells requires ongoing protein synthesis, suggesting several modes of regulation. In this report, we have characterized the transcriptional regulation of one family member, NF-kappa B2. The genomic structure and sequence of NF-kappa B2 revealed the presence of two promoters and at least four kappa B regulatory elements, which mediate responsiveness to phorbol myristate acetate and tumor necrosis factor alpha. Similar to other NF-kappa B family members, NF-kappa B2 is positively autoregulated. In contrast to other family members, we find that kappa B elements in the NFKB2 promoter can also mediate transcriptional repression in the absence of NF-kappa B. We identified a nuclear complex which binds specifically to a subset of kappa B-related sites but not to the canonical kappa B element. Because of its putative inhibitory or repressive effect, this binding activity has been termed Rep-kappa B. This mechanism of repressing basal NF-kappa B2 transcription in an inactivated state enables the cell to tightly control NF-kappa B2 activity. These data demonstrate that a novel mode of kappa B-dependent regulation is mediated by specific kappa B sites in the NFKB2 promoter.

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22

Mallory, Michael J., Michael J. Law, David E. Sterner, Shelley L. Berger, and Randy Strich. "Gcn5p-dependent acetylation induces degradation of the meiotic transcriptional repressor Ume6p." Molecular Biology of the Cell 23, no. 9 (May 2012): 1609–17. http://dx.doi.org/10.1091/mbc.e11-06-0536.

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Ume6p represses early meiotic gene transcription in Saccharomyces cerevisiae by recruiting the Rpd3p histone deacetylase and chromatin-remodeling proteins. Ume6p repression is relieved in a two-step destruction process mediated by the anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase. The first step induces partial Ume6p degradation when vegetative cells shift from glucose- to acetate-based medium. Complete proteolysis happens only upon meiotic entry. Here we demonstrate that the first step in Ume6p destruction is controlled by its acetylation and deacetylation by the Gcn5p acetyltransferase and Rpd3p, respectively. Ume6p acetylation occurs in medium lacking dextrose and results in a partial destruction of the repressor. Preventing acetylation delays Ume6p meiotic destruction and retards both the transient transcription program and execution of the meiotic nuclear divisions. Conversely, mimicking acetylation induces partial destruction of Ume6p in dextrose medium and accelerates meiotic degradation by the APC/C. These studies reveal a new mechanism by which acetyltransferase activity induces gene expression through targeted destruction of a transcriptional repressor. These findings also demonstrate an important role for nonhistone acetylation in the transition between mitotic and meiotic cell division.

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Yamamoto, Kaneyoshi, and Akira Ishihama. "Two different modes of transcription repression of the Escherichia coli acetate operon by IclR." Molecular Microbiology 47, no. 1 (December 18, 2002): 183–94. http://dx.doi.org/10.1046/j.1365-2958.2003.03287.x.

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Teramoto, Maki, Shigeaki Harayama, and Kazuya Watanabe. "PhcS Represses Gratuitous Expression of Phenol-Metabolizing Enzymes in Comamonas testosteroni R5." Journal of Bacteriology 183, no. 14 (July 15, 2001): 4227–34. http://dx.doi.org/10.1128/jb.183.14.4227-4234.2001.

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ABSTRACT We identified an open reading frame, designatedphcS, downstream of the transcriptional activator gene (phcR) for the expression of multicomponent phenol hydroxylase (mPH) in Comamonas testosteroni R5. The deduced product of phcS was homologous to AphS ofC. testosteroni TA441, which belongs to the GntR family of transcriptional regulators. The transformation of Pseudomonas aeruginosa PAO1c (phenol negative, catechol positive) with pROR502 containingphcR and the mPH genes conferred the ability to grow on phenol, while transformation with pROR504 containingphcS, phcR, and mPH genes did not confer this ability. The disruption of phcS in strain R5 had no effect on its phenol-oxygenating activity in a chemostat culture with phenol. The phenol-oxygenating activity was not expressed in strain R5 grown in a chemostat with acetate. In contrast, the phenol-oxygenating activity in the strain with a knockoutphcS gene when grown in a chemostat with acetate as the limiting growth factor was 66% of that obtained in phenol-grown cells of the strain with a knockout in the phcSgene. The disruption of phcS and/orphcR and the complementation in trans of these defects confirm that PhcS is a trans-acting repressor and that the unfavorable expression of mPH in thephcS knockout cells grown on acetate requires PhcR. These results show that the PhcS protein repressed the gratuitous expression of phenol-metabolizing enzymes in the absence of the genuine substrate and that strain R5 acted by an unknown mechanism in which the PhcS-mediated repression was overcome in the presence of the pathway substrate.

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25

Galushko, Alexander S., Snezanna K. Ibryaeva, Anna S. Zhuravleva, Gayane G. Panova, and Jacob H. Jacob. "Moderate thermophilic chemoorganoheterotrophic bacterium in surface layer of anthropogenic grounds of industrial estate area of Al-Mafraq, Jordan." Ecological genetics 19, no. 3 (October 10, 2021): 209–17. http://dx.doi.org/10.17816/ecogen70759.

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Surface of oil-contaminated soil from Industrial Estate of Al-Mafraq city, Jordan, was investigated for the presence of aerobic oil-degrading moderately thermophilic bacteria. A pure culture of spore forming aerobic chemoorganogeterotrophic rod shaped bacterial isolate, designated as strain j3n, was obtained. Phylogenetic analysis of the 16S rRNA gene sequence revealed that strain j3n is closely related to gram-positive bacteria of kaustophilus thermoleovorans cluster of Geobacillus genus. Strain j3n grew aerobically with oil, hexadecane, benzoate and acetate. Growth data indicated that utilization of hexadecane but not of oil and benzoate might be under catabolite repression control. Possibility of a regulation of alkane degradation by acetate in aerobic thermophilic gram-positive bacteria of Geobacillus spp. was shown for the first time.

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26

Bleichrodt, Fenja S., Rita Fischer, and Ulrike C. Gerischer. "The β-ketoadipate pathway of Acinetobacter baylyi undergoes carbon catabolite repression, cross-regulation and vertical regulation, and is affected by Crc." Microbiology 156, no. 5 (May 1, 2010): 1313–22. http://dx.doi.org/10.1099/mic.0.037424-0.

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The degradation of many structurally diverse aromatic compounds in Acinetobacter baylyi is accomplished by the β-ketoadipate pathway. In addition to specific induction of expression by certain aromatic compounds, this pathway is regulated by complex mechanisms at multiple levels, which are the topic of this study. Multiple operons feeding into the β-ketoadipate pathway are controlled by carbon catabolite repression (CCR) caused by succinate plus acetate. The pathways under study enable the catabolism of benzoate (ben), catechol (catA), cis,cis-muconate (catB,C,I,J,F,D), vanillate (van), hydroxycinnamates (hca), dicarboxylates (dca), salicylate (sal), anthranilate (ant) and benzyl esters (are). For analysis of CCR at the transcriptional level a luciferase reporter gene cassette was introduced into the operons. The Crc (catabolite repression control) protein is involved in repression of all operons (except for catA), as demonstrated by the analysis of respective crc strains. In addition, cross-regulation was demonstrated for the vanA,B, hca and dca operons. The presence of protocatechuate caused transcriptional repression of the vanA,B- and hca-encoded funnelling pathways (vertical regulation). Thus the results presented extend the understanding both of CCR and of the effects of Crc for all aromatic degradative pathways of A. baylyi and increase the number of operons known to be controlled by two additional mechanisms, cross-regulation and vertical regulation.

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Polen, T., D. Rittmann, V. F. Wendisch, and H. Sahm. "DNA Microarray Analyses of the Long-Term Adaptive Response of Escherichia coli to Acetate and Propionate." Applied and Environmental Microbiology 69, no. 3 (March 2003): 1759–74. http://dx.doi.org/10.1128/aem.69.3.1759-1774.2003.

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ABSTRACT In its natural environment, Escherichia coli is exposed to short-chain fatty acids, such as acetic acid or propionic acid, which can be utilized as carbon sources but which inhibit growth at higher concentrations. DNA microarray experiments revealed expression changes during exponential growth on complex medium due to the presence of sodium acetate or sodium propionate at a neutral external pH. The adaptive responses to acetate and propionate were similar and involved genes in three categories. First, the RNA levels for chemotaxis and flagellum genes increased. Accordingly, the expression of chromosomal fliC′-′lacZ and flhDC′-′lacZ fusions and swimming motility increased after adaptation to acetate or propionate. Second, the expression of many genes that are involved in the uptake and utilization of carbon sources decreased, indicating some kind of catabolite repression by acetate and propionate. Third, the expression of some genes of the general stress response increased, but the increases were more pronounced after short-term exposure for this response than for the adaptive response. Adaptation to propionate but not to acetate involved increased expression of threonine and isoleucine biosynthetic genes. The gene expression changes after adaptation to acetate or propionate were not caused solely by uncoupling or osmotic effects but represented specific characteristics of the long-term response of E. coli to either compound.

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Heyland, Jan, Jianan Fu, and Lars M. Blank. "Correlation between TCA cycle flux and glucose uptake rate during respiro-fermentative growth of Saccharomyces cerevisiae." Microbiology 155, no. 12 (December 1, 2009): 3827–37. http://dx.doi.org/10.1099/mic.0.030213-0.

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Glucose repression of the tricarboxylic acid (TCA) cycle in Saccharomyces cerevisiae was investigated under different environmental conditions using 13C-tracer experiments. Real-time quantification of the volatile metabolites ethanol and CO2 allowed accurate carbon balancing. In all experiments with the wild-type, a strong correlation between the rates of growth and glucose uptake was observed, indicating a constant yield of biomass. In contrast, glycerol and acetate production rates were less dependent on the rate of glucose uptake, but were affected by environmental conditions. The glycerol production rate was highest during growth in high-osmolarity medium (2.9 mmol g−1 h−1), while the highest acetate production rate of 2.1 mmol g−1 h−1 was observed in alkaline medium of pH 6.9. Under standard growth conditions (25 g glucose l−1 , pH 5.0, 30 °C) S. cerevisiae had low fluxes through the pentose phosphate pathway and the TCA cycle. A significant increase in TCA cycle activity from 0.03 mmol g−1 h−1 to about 1.7 mmol g−1 h−1 was observed when S. cerevisiae grew more slowly as a result of environmental perturbations, including unfavourable pH values and sodium chloride stress. Compared to experiments with high glucose uptake rates, the ratio of CO2 to ethanol increased more than 50 %, indicating an increase in flux through the TCA cycle. Although glycolysis and the ethanol production pathway still exhibited the highest fluxes, the net flux through the TCA cycle increased significantly with decreasing glucose uptake rates. Results from experiments with single gene deletion mutants partially impaired in glucose repression (hxk2, grr1) indicated that the rate of glucose uptake correlates with this increase in TCA cycle flux. These findings are discussed in the context of regulation of glucose repression.

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Olaniyi, Kehinde S., Oluwatobi A. Amusa, Isaac O. Ajadi, Bolanle Y. Alabi, Toluwani B. Agunbiade, and Mary B. Ajadi. "Repression of HDAC5 by acetate restores hypothalamic-pituitary-ovarian function in type 2 diabetes mellitus." Reproductive Toxicology 106 (December 2021): 69–81. http://dx.doi.org/10.1016/j.reprotox.2021.10.008.

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30

Doughty, D. M., L. A. Sayavedra-Soto, D. J. Arp, and P. J. Bottomley. "Product Repression of Alkane Monooxygenase Expression in Pseudomonas butanovora." Journal of Bacteriology 188, no. 7 (April 1, 2006): 2586–92. http://dx.doi.org/10.1128/jb.188.7.2586-2592.2006.

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ABSTRACT Physiological and regulatory mechanisms that allow the alkane-oxidizing bacterium Pseudomonas butanovora to consume C2 to C8 alkane substrates via butane monooxygenase (BMO) were examined. Striking differences were observed in response to even- versus odd-chain-length alkanes. Propionate, the downstream product of propane oxidation and of the oxidation of other odd-chain-length alkanes following β-oxidation, was a potent repressor of BMO expression. The transcriptional activity of the BMO promoter was reduced with as little as 10 μM propionate, even in the presence of appropriate inducers. Propionate accumulated stoichiometrically when 1-propanol and propionaldehyde were added to butane- and ethane-grown cells, indicating that propionate catabolism was inactive during growth on even-chain-length alkanes. In contrast, propionate consumption was induced (about 80 nmol propionate consumed · min−1 · mg protein−1) following growth on the odd-chain-length alkanes, propane and pentane. The induction of propionate consumption could be brought on by the addition of propionate or pentanoate to the growth medium. In a reporter strain of P. butanovora in which the BMO promoter controls β-galactosidase expression, only even-chain-length alcohols (C2 to C8) induced β-galactosidase following growth on acetate or butyrate. In contrast, both even- and odd-chain-length alcohols (C3 to C7) were able to induce β-galactosidase following the induction of propionate consumption by propionate or pentanoate.

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31

Goffin, Philippe, Lidia Muscariello, Frederique Lorquet, Aline Stukkens, Deborah Prozzi, Margherita Sacco, Michiel Kleerebezem, and Pascal Hols. "Involvement of Pyruvate Oxidase Activity and Acetate Production in the Survival of Lactobacillus plantarum during the Stationary Phase of Aerobic Growth." Applied and Environmental Microbiology 72, no. 12 (September 29, 2006): 7933–40. http://dx.doi.org/10.1128/aem.00659-06.

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ABSTRACT In addition to the previously characterized pyruvate oxidase PoxB, the Lactobacillus plantarum genome encodes four predicted pyruvate oxidases (PoxC, PoxD, PoxE, and PoxF). Each pyruvate oxidase gene was individually inactivated, and only the knockout of poxF resulted in a decrease in pyruvate oxidase activity under the tested conditions. We show here that L. plantarum has two major pyruvate oxidases: PoxB and PoxF. Both are involved in lactate-to-acetate conversion in the early stationary phase of aerobic growth and are regulated by carbon catabolite repression. A strain devoid of pyruvate oxidase activity was constructed by knocking out the poxB and poxF genes. In this mutant, acetate production was strongly affected, with lactate remaining the major end product of either glucose or maltose fermentation. Notably, survival during the stationary phase appeared to be dramatically improved in the poxB poxF double mutant.

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32

Donet, Eva, Pilar Bosch, Ana Sanchis, Pilar Bayo, Angel Ramírez, José L. Cascallana, Ana Bravo, and Paloma Paloma. "Transrepression Function of the Glucocorticoid Receptor Regulates Eyelid Development and Keratinocyte Proliferation but Is Not Sufficient to Prevent Skin Chronic Inflammation." Molecular Endocrinology 22, no. 4 (April 1, 2008): 799–812. http://dx.doi.org/10.1210/me.2007-0284.

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Glucocorticoids (GCs) play a key role in skin homeostasis and stress responses acting through the GC receptor (GR), which modulates gene expression by DNA binding-dependent (transactivation) and -independent (transrepression) mechanisms. To delineate which mechanisms underlie the beneficial and adverse effects mediated by GR in epidermis and other epithelia, we have generated transgenic mice that express a mutant GR (P493R, A494S), which is defective for transactivation but retains transrepression activity, under control of the keratin 5 promoter (K5-GR-TR mice). K5-GR-TR embryos exhibited eyelid opening at birth and corneal defects that resulted in corneal opacity in the adulthood. Transgenic embryos developed normal skin, although epidermal atrophy and focal alopecia was detected in adult mice. GR-mediated transrepression was sufficient to inhibit keratinocyte proliferation induced by acute and chronic phorbol 12-myristate 13-acetate exposure, as demonstrated by morphometric analyses, bromodeoxyuridine incorporation, and repression of keratin 6, a marker of hyperproliferative epidermis. These antiproliferative effects were mediated through negative interference of GR with MAPK/activator protein-1 and nuclear factor-κB activities, although these interactions occurred with different kinetics. However, phorbol 12-myristate 13-acetate-induced inflammation was only partially inhibited by GR-TR, which efficiently repressed IL-1β and MMP-3 genes while weakly repressing IL-6 and TNF-α. Our data highlight the relevance of deciphering the mechanisms underlying GR actions on epithelial morphogenesis as well as for its therapeutic use to identify more restricted targets of GC administration.

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Esposito, F., V. Agosti, G. Morrone, F. Morra, C. Cuomo, T. Russo, S. Venuta, and F. Cimino. "Inhibition of the differentiation of human myeloid cell lines by redox changes induced through glutathione depletion." Biochemical Journal 301, no. 3 (August 1, 1994): 649–53. http://dx.doi.org/10.1042/bj3010649.

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We have investigated the effect of redox changes in vivo on the differentiation of two human myeloid cell lines, HL-60 and KG-1. The glutathione-depleting agent diethyl maleate (DEM) prevented the development of differentiated features in response to phorbol esters, including adherence of the cells to plastic surfaces and repression of the myeloperoxidase and CD34 genes. Moreover, DEM abolished phorbol 12-myristate 13-acetate-induced activation of the transcription factors AP-1 and Egr-1, suggesting that inhibition of differentiation may be due, at least in part, to redox modifications of these proteins.

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Somerville, Greg A., Michael S. Chaussee, Carrie I. Morgan, J. Ross Fitzgerald, David W. Dorward, Lawrence J. Reitzer, and James M. Musser. "Staphylococcus aureus Aconitase Inactivation Unexpectedly Inhibits Post-Exponential-Phase Growth and Enhances Stationary-Phase Survival." Infection and Immunity 70, no. 11 (November 2002): 6373–82. http://dx.doi.org/10.1128/iai.70.11.6373-6382.2002.

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ABSTRACT Staphylococcus aureus preferentially catabolizes glucose, generating pyruvate, which is subsequently oxidized to acetate under aerobic growth conditions. Catabolite repression of the tricarboxylic acid (TCA) cycle results in the accumulation of acetate. TCA cycle derepression coincides with exit from the exponential growth phase, the onset of acetate catabolism, and the maximal expression of secreted virulence factors. These data suggest that carbon and energy for post-exponential-phase growth and virulence factor production are derived from the catabolism of acetate mediated by the TCA cycle. To test this hypothesis, the aconitase gene was genetically inactivated in a human isolate of S. aureus, and the effects on physiology, morphology, virulence factor production, virulence for mice, and stationary-phase survival were examined. TCA cycle inactivation prevented the post-exponential growth phase catabolism of acetate, resulting in premature entry into the stationary phase. This phenotype was accompanied by a significant reduction in the production of several virulence factors and alteration in host-pathogen interaction. Unexpectedly, aconitase inactivation enhanced stationary-phase survival relative to the wild-type strain. Aconitase is an iron-sulfur cluster-containing enzyme that is highly susceptible to oxidative inactivation. We speculate that reversible loss of the iron-sulfur cluster in wild-type organisms is a survival strategy used to circumvent oxidative stress induced during host-pathogen interactions. Taken together, these data demonstrate the importance of the TCA cycle in the life cycle of this medically important pathogen.

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BERREVOETS, Cor A., Arzu UMAR, Jan TRAPMAN, and Albert O. BRINKMANN. "Differential modulation of androgen receptor transcriptional activity by the nuclear receptor co-repressor (N-CoR)." Biochemical Journal 379, no. 3 (May 1, 2004): 731–38. http://dx.doi.org/10.1042/bj20031456.

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Antiandrogens are widely used agents in the treatment of prostate cancer, as inhibitors of AR (androgen receptor) action. Although the precise mechanism of antiandrogen action is not yet elucidated, recent studies indicate the involvement of nuclear receptor co-repressors. In the present study, the regulation of AR transcriptional activity by N-CoR (nuclear receptor co-repressor), in the presence of different ligands, has been investigated. Increasing levels of N-CoR differentially affected the transcriptional activity of AR occupied with either agonistic or antagonistic ligands. Small amounts of co-transfected N-CoR repressed CPA (cyproterone acetate)- and mifepristone (RU486)-mediated AR activity, but did not affect agonist (R1881)-induced AR activity. Larger amounts of co-transfected N-CoR repressed AR activity for all ligands, and converted the partial agonists CPA and RU486 into strong AR antagonists. In the presence of the agonist R1881, co-expression of the p160 co-activator TIF2 (transcriptional intermediary factor 2) relieved N-CoR repression up to control levels. However, in the presence of RU486 and CPA, TIF2 did not functionally compete with N-CoR, suggesting that antagonist-bound AR has a preference for N-CoR. The AR mutation T877A (Thr877→Ala), which is frequently found in prostate cancer and affects the ligand-induced conformational change of the AR, considerably reduced the repressive action of N-CoR. The agonistic activities of CPA- and hydroxyflutamide-occupied T877A-AR were hardly affected by N-CoR, whereas TIF2 strongly enhanced their activities. These results indicate that lack of N-CoR action allows these antiandrogens to act as strong agonists on the mutant AR.

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Löbs, Ann-Kathrin, Cory Schwartz, Sarah Thorwall, and Ian Wheeldon. "Highly Multiplexed CRISPRi Repression of Respiratory Functions Enhances Mitochondrial Localized Ethyl Acetate Biosynthesis in Kluyveromyces marxianus." ACS Synthetic Biology 7, no. 11 (October 24, 2018): 2647–55. http://dx.doi.org/10.1021/acssynbio.8b00331.

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37

Lopez de Felipe, Felix, and Philippe Gaudu. "Multiple control of the acetate pathway in Lactococcus lactis under aeration by catabolite repression and metabolites." Applied Microbiology and Biotechnology 82, no. 6 (April 2009): 1115–22. http://dx.doi.org/10.1007/s00253-009-1897-8.

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38

Fandl, J. P., L. K. Thorner, and S. W. Artz. "Mutations that affect transcription and cyclic AMP-CRP regulation of the adenylate cyclase gene (cya) of Salmonella typhimurium." Genetics 125, no. 4 (August 1, 1990): 719–27. http://dx.doi.org/10.1093/genetics/125.4.719.

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Abstract We studied the expression of the cya promoter(s) in cya-lac fusion strains of Salmonella typhimurium and demonstrated cAMP receptor protein (CRP)-dependent repression by cAMP. Expression of cya was reduced about fourfold in cultures grown in acetate minimal medium as compared to cultures grown in glucose-6-phosphate minimal medium. Expression of cya was also reduced about fourfold by addition of 5 mM cAMP to cultures grown in glucose minimal medium. We constructed in vitro deletion and insertion mutations altering a major cya promoter (P2) and a putative CRP binding site overlapping P2. These mutations were recombined into the chromosome by allele replacement with M13mp::cya recombinant phages and the regulation of the mutant promoters was analyzed. A 4-bp deletion of the CRP binding site and a 4-bp insertion in this site nearly eliminated repression by cAMP. A mutant with the P2 promoter and the CRP binding site both deleted exhibited an 80% reduction in cya expression; the 20% residual expression was insensitive to cAMP repression. This mutant retained a Cya+ phenotype. Taken together, the results establish that the cya gene is transcribed from multiple promoters one of which, P2, is negatively regulated by the cAMP-CRP complex. Correction for the contribution to transcription by the cAMP-CRP nonregulated cya promoters indicates that the P2 promoter is repressed at least eightfold by cAMP-CRP.

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Sierra-Ibarra, Estefanía, Alejandra Vargas-Tah, Cessna L. Moss-Acosta, Berenice Trujillo-Martínez, Eliseo R. Molina-Vázquez, Alberto Rosas-Aburto, Ángeles Valdivia-López, Martín G. Hernández-Luna, Eduardo Vivaldo-Lima, and Alfredo Martínez. "Co-Fermentation of Glucose–Xylose Mixtures from Agroindustrial Residues by Ethanologenic Escherichia coli: A Study on the Lack of Carbon Catabolite Repression in Strain MS04." Molecules 27, no. 24 (December 15, 2022): 8941. http://dx.doi.org/10.3390/molecules27248941.

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The production of biofuels, such as bioethanol from lignocellulosic biomass, is an important task within the sustainable energy concept. Understanding the metabolism of ethanologenic microorganisms for the consumption of sugar mixtures contained in lignocellulosic hydrolysates could allow the improvement of the fermentation process. In this study, the ethanologenic strain Escherichia coli MS04 was used to ferment hydrolysates from five different lignocellulosic agroindustrial wastes, which contained different glucose and xylose concentrations. The volumetric rates of glucose and xylose consumption and ethanol production depend on the initial concentration of glucose and xylose, concentrations of inhibitors, and the positive effect of acetate in the fermentation to ethanol. Ethanol yields above 80% and productivities up to 1.85 gEtOH/Lh were obtained. Furthermore, in all evaluations, a simultaneous co-consumption of glucose and xylose was observed. The effect of deleting the xyIR regulator was studied, concluding that it plays an important role in the metabolism of monosaccharides and in xylose consumption. Moreover, the importance of acetate was confirmed for the ethanologenic strain, showing the positive effect of acetate on the co-consumption rates of glucose and xylose in cultivation media and hydrolysates containing sugar mixtures.

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Tashiro, Satoshi, Akihiko Muto, Keiji Tanimoto, Haruka Tsuchiya, Hiroshi Suzuki, Hideto Hoshino, Minoru Yoshida, Joachim Walter, and Kazuhiko Igarashi. "Repression of PML Nuclear Body-Associated Transcription by Oxidative Stress-Activated Bach2." Molecular and Cellular Biology 24, no. 8 (April 15, 2004): 3473–84. http://dx.doi.org/10.1128/mcb.24.8.3473-3484.2004.

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ABSTRACT Several lines of evidence suggest that gene expression is regulated not only by the interaction between transcription factors and DNA but also by the higher-order architecture of the cell nucleus. PML bodies are one of the most prominent nuclear substructures which have been implicated in transcription regulation during apoptosis and stress responses. Bach2 is a member of the BTB-basic region leucine zipper factor family and represses transcription activity directed by the 12-O-tetradecanoylphorbol-13-acetate response element, the Maf recognition element, and the antioxidant-responsive element. Bach2 forms nuclear foci associated with PML bodies upon oxidative stress. Here, we demonstrate that transcription activity associated with PML bodies is selectively repressed by the recruitment of Bach2 around PML bodies. Fluorescence recovery after photobleaching experiments revealed that Bach2 showed rapid turnover in the nuclear foci. The Bach2 N-terminal region including the BTB domain is essential for the focus formation. Sumoylation of Bach2 is required for the recruitment of the protein around PML bodies. These observations represent the first example of modulation of transcription activity associated with PML bodies by a sequence-specific transcription factor upon oxidative stress.

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Lorquet, Frédérique, Philippe Goffin, Lidia Muscariello, Jean-Bernard Baudry, Victor Ladero, Margherita Sacco, Michiel Kleerebezem, and Pascal Hols. "Characterization and Functional Analysis of the poxB Gene, Which Encodes Pyruvate Oxidase in Lactobacillus plantarum." Journal of Bacteriology 186, no. 12 (June 15, 2004): 3749–59. http://dx.doi.org/10.1128/jb.186.12.3749-3759.2004.

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ABSTRACT The pyruvate oxidase gene (poxB) from Lactobacillus plantarum Lp80 was cloned and characterized. Northern blot and primer extension analyses revealed that transcription of poxB is monocistronic and under the control of a vegetative promoter. poxB mRNA expression was strongly induced by aeration and was repressed by glucose. Moreover, Northern blotting performed at different stages of growth showed that poxB expression is maximal in the early stationary phase when glucose is exhausted. Primer extension and in vivo footprint analyses revealed that glucose repression of poxB is mediated by CcpA binding to the cre site identified in the promoter region. The functional role of the PoxB enzyme was studied by using gene overexpression and knockout in order to evaluate its implications for acetate production. Constitutive overproduction of PoxB in L. plantarum revealed the predominant role of pyruvate oxidase in the control of acetate production under aerobic conditions. The ΔpoxB mutant strain exhibited a moderate (20 to 25%) decrease in acetate production when it was grown on glucose as the carbon source, and residual pyruvate oxidase activity that was between 20 and 85% of the wild-type activity was observed with glucose limitation (0.2% glucose). In contrast, when the organism was grown on maltose, the poxB mutation resulted in a large (60 to 80%) decrease in acetate production. In agreement with the latter observation, the level of residual pyruvate oxidase activity with maltose limitation (0.2% maltose) was less than 10% of the wild-type level of activity.

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McBride, K., L. Robitaille, S. Tremblay, S. Argentin, and M. Nemer. "fos/jun repression of cardiac-specific transcription in quiescent and growth-stimulated myocytes is targeted at a tissue-specific cis element." Molecular and Cellular Biology 13, no. 1 (January 1993): 600–612. http://dx.doi.org/10.1128/mcb.13.1.600-612.1993.

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Unlike that of skeletal muscle cells in which growth and differentiation appear mutually exclusive, growth stimulation of cardiac cells is characterized by transient expression of early response nuclear proto-oncogenes as well as induction of several cardiac-specific markers. This observation led to the speculation that these proto-oncogenes, particularly c-fos and c-jun, might act as positive regulators of cardiac transcription. We have examined the role of c-jun and c-fos in basal and growth-stimulated cardiac transcription, using the cardiac-specific atrial natriuretic factor (ANF) gene as a marker. The results indicate that c-jun and c-fos are negative regulators of ANF transcription. Inducers of jun and fos activity, such as mitogens and growth factors, inhibited endogenous ANF transcripts. In transient cotransfection assays, jun and fos were able to trans-repress the ANF promoter in both quiescent and alpha 1-adrenergic stimulated myocytes. This repression was specific to myocyte cultures and was not observed in nonmuscle cells. Deletion analysis indicated that repression does not require typical AP-1-binding sites (tetradecanoyl phorbol acetate response elements) or serum response elements but is targeted at a cardiac-specific element within the ANF promoter. Various Fos-related proteins, including Fra-1, Fos B, and v-Fos, were able to trans-repress ANF transcription. In addition, C-terminal c-fos mutants which no longer repress transcription of such early growth response genes as c-fos and EGR-1 retained the ability to repress ANF transcription. Repression by c-jun occurs via the N-terminal activation domain and does not require the DNA-binding domain, suggesting that proto-oncogene repression involves interaction with one or more limiting cardiac-specific coactivators.

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McBride, K., L. Robitaille, S. Tremblay, S. Argentin, and M. Nemer. "fos/jun repression of cardiac-specific transcription in quiescent and growth-stimulated myocytes is targeted at a tissue-specific cis element." Molecular and Cellular Biology 13, no. 1 (January 1993): 600–612. http://dx.doi.org/10.1128/mcb.13.1.600.

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Unlike that of skeletal muscle cells in which growth and differentiation appear mutually exclusive, growth stimulation of cardiac cells is characterized by transient expression of early response nuclear proto-oncogenes as well as induction of several cardiac-specific markers. This observation led to the speculation that these proto-oncogenes, particularly c-fos and c-jun, might act as positive regulators of cardiac transcription. We have examined the role of c-jun and c-fos in basal and growth-stimulated cardiac transcription, using the cardiac-specific atrial natriuretic factor (ANF) gene as a marker. The results indicate that c-jun and c-fos are negative regulators of ANF transcription. Inducers of jun and fos activity, such as mitogens and growth factors, inhibited endogenous ANF transcripts. In transient cotransfection assays, jun and fos were able to trans-repress the ANF promoter in both quiescent and alpha 1-adrenergic stimulated myocytes. This repression was specific to myocyte cultures and was not observed in nonmuscle cells. Deletion analysis indicated that repression does not require typical AP-1-binding sites (tetradecanoyl phorbol acetate response elements) or serum response elements but is targeted at a cardiac-specific element within the ANF promoter. Various Fos-related proteins, including Fra-1, Fos B, and v-Fos, were able to trans-repress ANF transcription. In addition, C-terminal c-fos mutants which no longer repress transcription of such early growth response genes as c-fos and EGR-1 retained the ability to repress ANF transcription. Repression by c-jun occurs via the N-terminal activation domain and does not require the DNA-binding domain, suggesting that proto-oncogene repression involves interaction with one or more limiting cardiac-specific coactivators.

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Vemuri, G. N., E. Altman, D. P. Sangurdekar, A. B. Khodursky, and M. A. Eiteman. "Overflow Metabolism in Escherichia coli during Steady-State Growth: Transcriptional Regulation and Effect of the Redox Ratio." Applied and Environmental Microbiology 72, no. 5 (May 2006): 3653–61. http://dx.doi.org/10.1128/aem.72.5.3653-3661.2006.

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ABSTRACT Overflow metabolism in the form of aerobic acetate excretion by Escherichia coli is an important physiological characteristic of this common industrial microorganism. Although acetate formation occurs under conditions of high glucose consumption, the genetic mechanisms that trigger this phenomenon are not clearly understood. We report on the role of the NADH/NAD ratio (redox ratio) in overflow metabolism. We modulated the redox ratio in E. coli through the expression of Streptococcus pneumoniae (water-forming) NADH oxidase. Using steady-state chemostat cultures, we demonstrated a strong correlation between acetate formation and this redox ratio. We furthermore completed genome-wide transcription analyses of a control E. coli strain and an E. coli strain overexpressing NADH oxidase. The transcription results showed that in the control strain, several genes involved in the tricarboxylic acid (TCA) cycle and respiration were repressed as the glucose consumption rate increased. Moreover, the relative repression of these genes was alleviated by expression of NADH oxidase and the resulting reduced redox ratio. Analysis of a promoter binding site upstream of the genes which correlated with redox ratio revealed a degenerate sequence with strong homology with the binding site for ArcA. Deletion of arcA resulted in acetate reduction and increased the biomass yield due to the increased capacities of the TCA cycle and respiration. Acetate formation was completely eliminated by reducing the redox ratio through expression of NADH oxidase in the arcA mutant, even at a very high glucose consumption rate. The results provide a basis for studying new regulatory mechanisms prevalent at reduced NADH/NAD ratios, as well as for designing more efficient bioprocesses.

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Rohel, Eric A., Andrew C. Payne, Bart A. Fraaije, and Derek W. Hollomon. "Exploring Infection of Wheat and Carbohydrate Metabolism in Mycosphaerella graminicola Transformants with Differentially Regulated Green Fluorescent Protein Expression." Molecular Plant-Microbe Interactions® 14, no. 2 (February 2001): 156–63. http://dx.doi.org/10.1094/mpmi.2001.14.2.156.

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A Mycosphaerella graminicola strain transformed with the green fluorescent protein (GFP) downstream of either a carbon source-repressed promoter or a constitutive promoter was used to investigate in situ carbohydrate uptake during penetration of the fungus in wheat leaves. The promoter region of the acu-3 gene from Neurospora crassa encoding isocitrate lyase was used as a carbon source-repressed promoter. The promoter region of the Aspergillus nidulans gpdA gene encoding glyceraldehyde-3-phosphate dehydrogenase was used as a constitutive promoter. Fluorometric measurement of GFP gene expression in liquid cultures of acu-3-regulated transformants indicated that the N. crassa acu-3 promoter functions in M. graminicola as it does in N. crassa, i.e., acetate induced and carbon source repressed. Glucose, fructose, and saccharose triggered the repression, whereas mannitol, xylose, and cell wall polysaccharides did not. Monitoring the GFP level during fungal infection of wheat leaves revealed that acu-3 promoter repression occurred after penetration until sporulation, when newly differentiated pycnidiospores fluoresced. The use of GFP transformants also allowed clear visualization of M. graminicola pathogenesis. No appressoria were formed, but penetration at cell junctions was observed. These results give new insight into the biotrophic status of M. graminicola.

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Roychowdhury, H. S., and M. Kapoor. "Ethanol and carbon-source starvation enhance the accumulation of HSP80 in Neurospora crassa." Canadian Journal of Microbiology 34, no. 2 (February 1, 1988): 162–68. http://dx.doi.org/10.1139/m88-031.

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In Neurospora crassa, heat shock results in the induction of 9 to 11 heat shock proteins (HSP), of which HSP80 is the most abundant and the first to be synthesized. The induction of HSP80 was investigated during normal growth (2% sucrose) and under sucrose starvation. Transfer of mycelium to a medium supplemented with ethanol stimulated the synthesis of HSP80, even at the normal growth temperature of 28 °C. It was also synthesized under carbon starvation conditions, where the medium was supplemented with 0.02% sucrose, 0.3% acetate, 0.2% lactate, or ethanol. A 30–35 kilodalton polypeptide was induced by heat shock in carbon-sufficient media, but in 0.02% sucrose and 0.3% acetate containing media it was synthesized at normal temperatures. While the overall heat shock response remained unaltered in these cultures, the abundance of HSP90 and HSP70, relative to HSP80, was greater. HSP80 appears to be controlled by carbon-catabolite repression as well as heat shock. Another high molecular mass protein (tentatively designated alc'80') was observed to be induced by heat shock, provided carbon starvation conditions prevailed concurrently.

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Suleau, Audrey, Pierre Gourdon, Joëlle Reitz-Ausseur, and Serge Casaregola. "Transcriptomic Analysis of Extensive Changes in Metabolic Regulation in Kluyveromyces lactis Strains." Eukaryotic Cell 5, no. 8 (August 2006): 1360–70. http://dx.doi.org/10.1128/ec.00087-06.

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ABSTRACT Genome-wide analysis of transcriptional regulation is generally carried out on well-characterized reference laboratory strains; hence, the characteristics of industrial isolates are therefore overlooked. In a previous study on the major cheese yeast Kluyveromyces lactis, we have shown that the reference strain and an industrial strain used in cheese making display a differential gene expression when grown on a single carbon source. Here, we have used more controlled conditions, i.e., growth in a fermentor with pH and oxygen maintained constant, to study how these two isolates grown in glucose reacted to an addition of lactose. The observed differences between sugar consumption and the production of various metabolites, ethanol, acetate, and glycerol, correlated with the response were monitored by the analysis of the expression of 482 genes. Extensive differences in gene expression between the strains were revealed in sugar transport, glucose repression, ethanol metabolism, and amino acid import. These differences were partly due to repression by glucose and another, yet-unknown regulation mechanism. Our results bring to light a new type of K. lactis strain with respect to hexose transport gene content and repression by glucose. We found that a combination of point mutations and variation in gene regulation generates a biodiversity within the K. lactis species that was not anticipated. In contrast to S. cerevisiae, in which there is a massive increase in the number of sugar transporter and fermentation genes, in K. lactis, interstrain diversity in adaptation to a changing environment is based on small changes at the level of key genes and cell growth control.

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Sagee, Shira, Amir Sherman, Galit Shenhar, Kenneth Robzyk, Noa Ben-Doy, Giora Simchen, and Yona Kassir. "Multiple and Distinct Activation and Repression Sequences Mediate the Regulated Transcription of IME1, a Transcriptional Activator of Meiosis-Specific Genes inSaccharomyces cerevisiae." Molecular and Cellular Biology 18, no. 4 (April 1, 1998): 1985–95. http://dx.doi.org/10.1128/mcb.18.4.1985.

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ABSTRACT IME1 encodes a transcriptional activator required for the transcription of meiosis-specific genes and initiation of meiosis in Saccharomyces cerevisiae. The transcription ofIME1 is repressed in the presence of glucose, and a low basal level of IME1 RNA is observed in vegetative cultures with acetate as the sole carbon source. Upon nitrogen depletion a transient induction in the transcription of IME1 is observed in MATa/MATα diploids but not in MAT-insufficient strains. In this study we demonstrate that the transcription of IME1 is controlled by an extremely unusual large 5′ region, over 2,100 bp long. This area is divided into four different upstream controlling sequences (UCS). UCS2 promotes the transcription of IME1 in the presence of a nonfermentable carbon source. UCS2 is flanked by three negative regions: UCS1, which exhibits URS activity in the presence of nitrogen, and UCS3 and UCS4, which repress the activity of UCS2 in MAT-insufficient cells. UCS2 consists of alternate positive and negative elements: three distinct constitutive URS elements that prevent the function of any upstream activating sequence (UAS) under all growth conditions, a constitutive UAS element that promotes expression under all growth conditions, a UAS element that is active only in vegetative media, and two discrete elements that function as UASs in the presence of acetate. Sequence analysis of IME1 revealed the presence of two almost identical 30- to 32-bp repeats. Surprisingly, one repeat, IREd, exhibits constitutive URS activity, whereas the other repeat, IREu, serves as a carbon-source-regulated UAS element. The RAS-cyclic AMP-dependent protein kinase cAPK pathway prevents the UAS activity of IREu in the presence of glucose as the sole carbon source, while the transcriptional activators Msn2p and Msn4p promote the UAS activity of this repeat in the presence of acetate. We suggest that the use of multiple negative and positive elements is essential to restrict transcription to the appropriate conditions and that the combinatorial effect of the entire region leads to the regulated transcription ofIME1.

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Park, Sun-Yang, Min-Woo Moon, Bindu Subhadra, and Jung-Kee Lee. "Functional characterization of theglxRdeletion mutant ofCorynebacterium glutamicumATCC 13032: involvement of GlxR in acetate metabolism and carbon catabolite repression." FEMS Microbiology Letters 304, no. 2 (March 2010): 107–15. http://dx.doi.org/10.1111/j.1574-6968.2009.01884.x.

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Borghese, Roberto, Silvia Cicerano, and Davide Zannoni. "Fructose increases the resistance of Rhodobacter capsulatus to the toxic oxyanion tellurite through repression of acetate permease (ActP)." Antonie van Leeuwenhoek 100, no. 4 (July 7, 2011): 655–58. http://dx.doi.org/10.1007/s10482-011-9619-5.

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Journal articles on the topic 'Acetate repression'

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