RamB Is an Activator of the Pyruvate Dehydrogenase Complex Subunit E1p Gene in &lt;i&gt;Corynebacterium glutamicum&lt;/i&gt;

Blombach, Bastian; Cramer, Annette; Eikmanns, Bernhard J.; Schreiner, Mark E.

doi:10.1159/000108782

Cited by 20 publications

(18 citation statements)

References 15 publications

(13 reference statements)

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“…The genes pfkA, fba, and ldhA are not known targets of the carbon regulators AcnR (represses aconitase gene acn [41]), GntR1 and GntR2 (repress gluconate utilization genes gntP, gntK, and gnd and activate ptsG and ptsS [10]), GlxR (represses gntP, gntK, and isocitrate lyase and malate synthase genes aceA and aceB [38,42]), and LldR (represses the Llactate utilization operon cg3226-lldD [23]). RamB was shown to repress its own gene, aceA, aceB, the acetate activation operon pta-ack, and the alcohol dehydrogenase gene adhA and to activate aceE, which encodes subunit E1 of pyruvate dehydrogenase (2,7,24). The occurrence of RamB binding motifs suggests that ptsG, the tricarboxylic acid (TCA) cycle genes gltA and acn, and the phosphoenolpyruvate carboxykinase and malic enzyme genes pck and malE are regulated by RamB (3).…”

Section: Discussionmentioning

confidence: 99%

The Global Repressor SugR Controls Expression of Genes of Glycolysis and of the l -Lactate Dehydrogenase LdhA in Corynebacterium glutamicum

Engels

Lindner²,

Wendisch³

2008

J Bacteriol

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The transcriptional regulator SugR from Corynebacterium glutamicum represses genes of the phosphoenolpyruvate-dependent phosphotransferase system (PTS). Growth experiments revealed that the overexpression of sugR not only perturbed the growth of C. glutamicum on the PTS sugars glucose, fructose, and sucrose but also led to a significant growth inhibition on ribose, which is not taken up via the PTS. Chromatin immunoprecipitation combined with DNA microarray analysis and gel retardation experiments were performed to identify further target genes of SugR. Gel retardation analysis confirmed that SugR bound to the promoter regions of genes of the glycolytic enzymes 6-phosphofructokinase (pfkA), fructose-1,6-bisphosphate aldolase (fba), enolase (eno), pyruvate kinase (pyk), and NAD-dependent L-lactate dehydrogenase (ldhA). The deletion of sugR resulted in increased mRNA levels of eno, pyk, and ldhA in acetate medium. Enzyme activity measurements revealed that SugR-mediated repression affects the activities of PfkA, Fba, and LdhA in vivo. As the deletion of sugR led to increased LdhA activity under aerobic and under oxygen deprivation conditions, L-lactate production by C. glutamicum was determined. The overexpression of sugR reduced L-lactate production by about 25%, and sugR deletion increased L-lactate formation under oxygen deprivation conditions by threefold. Thus, SugR functions as a global repressor of genes of the PTS, glycolysis, and fermentative L-lactate dehydrogenase in C. glutamicum.Corynebacterium glutamicum, which was isolated as an Lglutamate-excreting soil bacterium (1, 39), is a predominantly aerobic, biotin-auxotrophic, gram-positive bacterium widely used for the industrial production of more than 2 million tons of amino acids per year, mainly L-glutamate and L-lysine (31,43). A general view of this nonpathogenic bacterium, which has become a model organism for the Corynebacterineae, a suborder of Actinomycetales that also comprises the genus Mycobacterium (54), can be found in two recent monographs (9, 17).C. glutamicum is able to grow on a variety of sugars, sugar alcohols, and organic acids as sole carbon and energy sources (64). As in many other gram-positive and gram-negative bacteria, the phosphoenolpyruvate-dependent phosphotransferase system (PTS) is the major sugar uptake system (15,37,45,47). The PTS-mediated glucose, fructose, and sucrose uptake in C. glutamicum operates by phosphoryl group transfer from phosphoenolpyruvate via EI (encoded by ptsI) and HPr (ptsH) to the sugar-specific permeases EII Glc , EII Fru , and EII Suc , respectively (ptsG, ptsF, and ptsS, respectively).

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Section: Discussionmentioning

confidence: 99%

The Global Repressor SugR Controls Expression of Genes of Glycolysis and of the l -Lactate Dehydrogenase LdhA in Corynebacterium glutamicum

Engels

Lindner²,

Wendisch³

2008

J Bacteriol

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“…RamA additionally controls the ramB gene , the gltA gene, the acn gene and the sdhCAB operon, encoding the TCA cycle enzymes aconitase and succinate dehydrogenase Bussmann et al, 2009;Van Ooyen et al, 2010), the gapA gene, encoding glyceraldehyde-3-phosphate dehydrogenase (Toyoda et al, 2009a), the surface-layer protein gene cspB (Hansmeier et al, 2006) and the resuscitation promoting factor 2 gene rpf2 . RamB additionally controls the aceE gene, encoding E1p subunit of the pyruvate dehydrogenase complex (Blombach et al, 2009). From all these results it can be concluded that both RamA and RamB have wide significance as transcriptional regulators in C. glutamicum and play a major role in coordination of its metabolism.…”

Section: Introductionmentioning

confidence: 90%

RamA and RamB are global transcriptional regulators in Corynebacterium glutamicum and control genes for enzymes of the central metabolism

Auchter

Cramer

Hüser

et al. 2011

Journal of Biotechnology

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“…These current and previous findings suggest that, besides basal upregulation by RamA, gapA expression is enhanced in the presence of glucose by inactivating SugR and activating GlxR with sugar metabolites and cAMP, respectively. While pfk is negatively regulated by SugR and RamA (4,27), aceE is positively controlled by RamB, a repressor of acetate utilization genes, under nutrient-rich conditions (10). The binding sites of these regulators in the promoter regions of gapA, pfk, and aceE do not overlap the GlxR-binding sites, eliminating the possibility that the mutations in the GlxR-binding sites affect binding of these regulators.…”

Section: Vol 193 2011mentioning

confidence: 99%

Genome-Wide Identification of In Vivo Binding Sites of GlxR, a Cyclic AMP Receptor Protein-Type Regulator in Corynebacterium glutamicum

et al. 2011

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Corynebacterium glutamicum GlxR is a cyclic AMP (cAMP) receptor protein-type regulator. Although over 200 GlxR-binding sites in the C. glutamicum genome are predicted in silico, studies on the physiological function of GlxR have been hindered by the severe growth defects of a glxR mutant. This study identified the GlxR regulon by chromatin immunoprecipitation in conjunction with microarray (ChIP-chip) analyses. In total, 209 regions were detected as in vivo GlxR-binding sites. In vitro binding assays and promoter-reporter assays demonstrated that GlxR directly activates expression of genes for aerobic respiration, ATP synthesis, and glycolysis and that it is required for expression of genes for cell separation and mechanosensitive channels. GlxR also directly represses a citrate uptake gene in the presence of citrate. Moreover, ChIP-chip analyses showed that GlxR was still able to interact with its target sites in a mutant with a deletion of cyaB, the sole adenylate cyclase gene in the genome, even though binding affinity was markedly decreased. Thus, GlxR is physiologically functional at the relatively low cAMP levels in the cyaB mutant, allowing the cyaB mutant to grow much better than the glxR mutant.

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RamB Is an Activator of the Pyruvate Dehydrogenase Complex Subunit E1p Gene in <i>Corynebacterium glutamicum</i>

Cited by 20 publications

References 15 publications

The Global Repressor SugR Controls Expression of Genes of Glycolysis and of the l -Lactate Dehydrogenase LdhA in Corynebacterium glutamicum

The Global Repressor SugR Controls Expression of Genes of Glycolysis and of the l -Lactate Dehydrogenase LdhA in Corynebacterium glutamicum

RamA and RamB are global transcriptional regulators in Corynebacterium glutamicum and control genes for enzymes of the central metabolism

Genome-Wide Identification of In Vivo Binding Sites of GlxR, a Cyclic AMP Receptor Protein-Type Regulator in Corynebacterium glutamicum

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