Identification of a functional promoter for the Escherichia coli gdhA gene and its regulation

Riba, Laura; Becerril, Baltazar; Servı́n‐González, Luis; Valle, Fernando; Bolívar, Francisco

doi:10.1016/0378-1119(88)90040-6

Cited by 17 publications

(14 citation statements)

References 43 publications

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“…However, choice of carbon source, such as citrate, a major component of urine, had a profound effect on gdhA expression. Rich media (19), the presence of specific amino acids in minimal medium (68), or a greater carbon/nitrogen ratio (69) have been reported to repress gdhA. Only when citrate was used as the carbon source, which forces the TCA cycle to operate, did we see a concomitant decrease in glnA expression.…”

Section: Discussionmentioning

confidence: 62%

Transcriptome of Proteus mirabilis in the Murine Urinary Tract: Virulence and Nitrogen Assimilation Gene Expression

et al. 2011

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The enteric bacterium Proteus mirabilis is a common cause of complicated urinary tract infections. In this study, microarrays were used to analyze P. mirabilis gene expression in vivo from experimentally infected mice. Urine was collected at 1, 3, and 7 days postinfection, and RNA was isolated from bacteria in the urine for transcriptional analysis. Across nine microarrays, 471 genes were upregulated and 82 were downregulated in vivo compared to in vitro broth culture. Genes upregulated in vivo encoded mannose-resistant Proteus-like (MR/P) fimbriae, urease, iron uptake systems, amino acid and peptide transporters, pyruvate metabolism enzymes, and a portion of the tricarboxylic acid (TCA) cycle enzymes. Flagella were downregulated. Ammonia assimilation gene glnA (glutamine synthetase) was repressed in vivo, while gdhA (glutamate dehydrogenase) was upregulated in vivo. Contrary to our expectations, ammonia availability due to urease activity in P. mirabilis did not drive this gene expression. A gdhA mutant was growth deficient in minimal medium with citrate as the sole carbon source, and loss of gdhA resulted in a significant fitness defect in the mouse model of urinary tract infection. Unlike Escherichia coli, which represses gdhA and upregulates glnA in vivo and cannot utilize citrate, the data suggest that P. mirabilis uses glutamate dehydrogenase to monitor carbon-nitrogen balance, and this ability contributes to the pathogenic potential of P. mirabilis in the urinary tract.

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Section: Discussionmentioning

confidence: 62%

Transcriptome of Proteus mirabilis in the Murine Urinary Tract: Virulence and Nitrogen Assimilation Gene Expression

et al. 2011

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“…It has been reported that there is no NR I -P binding sites in the gdhA regulatory region [31], and it is unlikely for NR I to directly repress gdhA promoter [32]. As it has been shown that Nac is involved in the transcriptional repression of gdhA gene under N-limitation [32], Nac seems to repress gdhA gene as shown in Fig.…”

Section: Discussionmentioning

confidence: 98%

Metabolic regulation of Escherichia coli and its gdhA, glnL, gltB, D mutants under different carbon and nitrogen limitations in the continuous culture

Kumar

Shimizu

2010

Microb Cell Fact

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BackgroundIt is quite important to understand how the central metabolism is regulated under nitrogen (N)- limitation as well as carbon (C)- limitation. In particular, the effect of C/N ratio on the metabolism is of practical interest for the heterologous protein production, PHB production, etc. Although the carbon and nitrogen metabolisms are interconnected and the overall mechanism is complicated, it is strongly desirable to clarify the effects of culture environment on the metabolism from the practical application point of view.ResultsThe effect of C/N ratio on the metabolism in Escherichia coli was investigated in the aerobic continuous culture at the dilution rate of 0.2 h-1 based on fermentation data, transcriptional RNA level, and enzyme activity data. The glucose concentration was kept at 10 g/l, while ammonium sulfate concentration was varied from 5.94 to 0.594 g/l. The resultant C/N ratios were 1.68 (100%), 2.81(60%), 4.21(40%), 8.42(20%), and 16.84(10%), where the percentage values in brackets indicate the ratio of N- concentration as compared to the case of 5.94 g/l of ammonium sulfate. The mRNA levels of crp and mlc decreased, which caused ptsG transcript expression to be up-regulated as C/N ratio increased. As C/N ratio increased cra transcript expression decreased, which caused ptsH, pfkA, and pykF to be up-regulated. At high C/N ratio, transcriptional mRNA level of soxR/S increased, which may be due to the activated respiratory chain as indicated by up-regulations of such genes as cyoA, cydB, ndh as well as the increase in the specific CO2 production rate. The rpoN transcript expression increased with the increase in C/N ratio, which led glnA, L, G and gltD transcript expression to change in similar fashion. The nac transcript expression showed similar trend as rpoN, while gdhA transcript expression changed in reverse direction. The transcriptional mRNA level of glnB, which codes for PII, glnD and glnK increased as C/N ratio increases. It was shown that GS-GOGAT pathway was activated for gdhA mutant under N- rich condition. In the case of glnL mutant, GOGAT enzyme activity was reduced as compared to the wild type under N- limitation. In the case of gltB, D mutants, GDH and GS enzymes were utilized under both N- rich and N- limited conditions. In this case, the transcriptional mRNA level of gdhA and corresponding GDH enzyme activity was higher under N- limitation as compared to N- rich condition.ConclusionThe metabolic regulation of E.coli was clarified under both carbon (C)- limitation and nitrogen (N)- limitation based on fermentation, transcriptional mRNA level and enzyme activities. The overall regulation mechanism was proposed. The effects of knocking out N- assimilation pathway genes were also clarified.

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“…However, transcriptional regulation of the corresponding genes differs significantly. For example, gltBD expression in E. coli is influenced by a number of regulators including LRP and CRP (for summary, see Reitzer, 1996) and gdhA transcription is repressed moderately by nitrogen limitation (Riba et al, 1988), while in this study we showed that gltBD transcription is regulated in C. glutamicum via AmtR and previous studies revealed no down-regulation of GDH activity in response to ammonium limitation (Bo$ rmann et al, 1992 ;Tesch et al, 1998). Also in comparison to Bacillus subtilis, the model organism for Gram-positive bacteria with low GjC content, assimilation of ammonium is organized differently in the high-GjC-content C. glutamicum.…”

Section: Discussionmentioning

confidence: 99%

Glutamate synthase of Corynebacterium glutamicum is not essential for glutamate synthesis and is regulated by the nitrogen status

2001

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The Corynebacterium glutamicum gltB and gltD genes, encoding the large (α) and small (β) subunit of glutamate synthase (GOGAT), were investigated in this study. Using RT-PCR, a common transcript of gltB and gltD was shown. Reporter gene assays and Northern hybridization experiments revealed that transcription of this operon depends on nitrogen starvation. The expression of gltBD is under control of the global repressor protein AmtR as demonstrated by gel shift experiments and analysis of gltB transcription in an amtR deletion strain. In contrast to other bacteria, in C. glutamicum GOGAT plays no pivotal role ; e.g. gltB and gltD inactivation did not result in growth defects when cells were grown in standard minimal medium and only a slight increase in the doubling time of the corresponding mutant strains was observed in the presence of limiting amounts of ammonia or urea. Additionally, mutant analyses revealed that GOGAT has no essential function in glutamate production by C. glutamicum.

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Identification of a functional promoter for the Escherichia coli gdhA gene and its regulation

Cited by 17 publications

References 43 publications

Transcriptome of Proteus mirabilis in the Murine Urinary Tract: Virulence and Nitrogen Assimilation Gene Expression

Transcriptome of Proteus mirabilis in the Murine Urinary Tract: Virulence and Nitrogen Assimilation Gene Expression

Metabolic regulation of Escherichia coli and its gdhA, glnL, gltB, D mutants under different carbon and nitrogen limitations in the continuous culture

Glutamate synthase of Corynebacterium glutamicum is not essential for glutamate synthesis and is regulated by the nitrogen status

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