In vivo requirement of integration host factor for nar (nitrate reductase) operon expression in Escherichia coli K-12.

Rabin, Ross S.; Collins, L A; Stewart, Valley

doi:10.1073/pnas.89.18.8701

Cited by 44 publications

(28 citation statements)

References 43 publications

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“…This site is centered at approximately -115 in relation to the start of transcription of promoter 6 and is located between two putative FNR binding sites (34). Mutagenesis of the 13-bp consensus sequence (23) (32,43). A particularly relevant example is the control of the narGHJI operon, whose expression is regulated by anaerobiosis and by nitrate (32).…”

Section: Resultsmentioning

confidence: 99%

“…Mutagenesis of the 13-bp consensus sequence (23) (32,43). A particularly relevant example is the control of the narGHJI operon, whose expression is regulated by anaerobiosis and by nitrate (32). The FNR protein induces expression anaerobically, and evidence indicates that it probably binds to a specific recognition sequence located around position -40 bp relative to the transcription initiation site (41).…”

Section: Resultsmentioning

confidence: 99%

“…Nitrate regulation is mediated by a second, distinct protein called NarL, which has been proposed to be a sequence-specific DNA-binding protein whose recognition sequence is located some 200 bp upstream of the transcription start site of the narGHJI operon (6). The NarL-mediated nitrate regulation of the promoter requires IHF, which recognizes and binds a DNA sequence located between the two putative activator binding sites (32,36). In an IHF-strain, anaerobic, FNRdependent activation of expression still occurred but NarLdependent nitrate regulation was abolished (32,36).…”

Section: Resultsmentioning

confidence: 99%

“…IHF is a sequence-specific DNA-binding and -bending protein encoded by the himA and himD (hip) genes of E. coli (29). IHF participates in a number of processes involving DNA including site-specific recombination, DNA replication, and positive or negative effects on gene expression (10,12 (4,16,32,36 (15).…”

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confidence: 99%

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Integration host factor is required for anaerobic pyruvate induction of pfl operon expression in Escherichia coli

et al. 1993

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The expression of the pyruvate formate-lyase gene (pfl) is induced by anaerobic growth, and this is increased further by growth in pyruvate. Previous work has shown that anaerobic induction is strongly dependent on the activator FNR and partially dependent on a second transcription factor, ArcA, while pyruvate induction only required FNR. Anaerobic and pyruvate regulation both require the presence of a 5' nontranslated regulatory sequence which spans approximately 500 bp of DNA. A mobility shift assay was developed to identify proteins that bind to this regulatory region. Several binding activities were separated by heparin agarose chromatography, and one of these activities was characterized and shown to be integration host factor (IHF). Mobility shift and DNase I footprinting experiments defined a single IHF binding site in the pfl promoter-regulatory region. With pfl-lacZ fusions, it could be shown that introduction of a himD mutation abolished pyruvate-dependent induction of anaerobic expression in vivo. The same result was observed when the pfl IHF binding site was mutated. In addition, the partial anaerobic induction of expression found in an fnr strain was completely blocked in an fnr himD double mutant and in an fnr IHF binding site double mutant. Taken together, these data suggest that IHF is necessary for both pyruvate induction and the anaerobic induction mediated by ArcA.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Integration host factor is required for anaerobic pyruvate induction of pfl operon expression in Escherichia coli

et al. 1993

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“…The fusion construct was crossed into bacteriophage RS45 (50), and monocopy lysogens were identified by a whole-colony PCR test (41). Similarly constructed ⌽(narG-lacZ) gene and ⌽(napF-lacZ) operon fusions have been described previously (16,42).…”

Section: Methodsmentioning

confidence: 99%

Periplasmic Nitrate Reductase (NapABC Enzyme) Supports Anaerobic Respiration byEscherichia coliK-12

2002

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Periplasmic nitrate reductase (NapABC enzyme) has been characterized from a variety of proteobacteria, especially Paracoccus pantotrophus. Whole-genome sequencing of Escherichia coli revealed the structural genes napFDAGHBC, which encode NapABC enzyme and associated electron transfer components. E. coli also expresses two membrane-bound proton-translocating nitrate reductases, encoded by the narGHJI and narZYWV operons. We measured reduced viologen-dependent nitrate reductase activity in a series of strains with combinations of nar and nap null alleles. The napF operon-encoded nitrate reductase activity was not sensitive to azide, as shown previously for the P. pantotrophus NapA enzyme. A strain carrying null alleles of narG and narZ grew exponentially on glycerol with nitrate as the respiratory oxidant (anaerobic respiration), whereas a strain also carrying a null allele of napA did not. By contrast, the presence of napA ؉ had no influence on the more rapid growth of narG ؉ strains. These results indicate that periplasmic nitrate reductase, like fumarate reductase, can function in anaerobic respiration but does not constitute a site for generating proton motive force. The time course of ⌽(napF-lacZ) expression during growth in batch culture displayed a complex pattern in response to the dynamic nitrate/nitrite ratio. Our results are consistent with the observation that ⌽(napFlacZ) is expressed preferentially at relatively low nitrate concentrations in continuous cultures (H. Wang, C.-P. Tseng, and R. P. Gunsalus, J. Bacteriol. 181:5303-5308, 1999). This finding and other considerations support the hypothesis that NapABC enzyme may function in E. coli when low nitrate concentrations limit the bioenergetic efficiency of nitrate respiration via NarGHI enzyme. Nitrate (NO 3Ϫ ), which is relatively abundant in many environments, has three functions in bacterial physiology. Nitrate assimilation provides a source of ammonium for biosynthesis (reviewed in reference 29), nitrate respiration generates proton motive force for energy (reviewed in references 4, 21, and 65), and nitrate dissimilation oxidizes excess reducing equivalents (reviewed in reference 36).Membrane-bound nitrate reductase (NarGHI enzyme; nitrate reductase A) employs a redox loop to couple quinol oxidation with proton translocation, thereby generating proton motive force for anaerobic respiration. The Escherichia coli and Paracoccus denitrificans enzymes have been the focus of most biochemical studies (reviewed in references 4, 21, and 65). This enzyme contains Mo-molybdopterin guanine dinucleotide, five iron-sulfur clusters, and diheme cytochrome b 556 . NarGHI enzyme activity is inhibited by azide (N 3 Ϫ ). Enzyme synthesis is maximally induced during anaerobic growth in the presence of nitrate.Periplasmic nitrate reductase (NapABC enzyme; nitrate reductase P) also oxidizes quinol, but it is thought that this enzyme is not a coupling site for proton translocation (reviewed in reference 4). Therefore, this enzyme is responsible for nitrate dissimilati...

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Co-ordinated regulation of amino sugar biosynthesis and degradation: the NagC repressor acts as both an activator and a repressor for the transcription of the glmUS operon and requires two separated NagC binding sites.

1995

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The NagC repressor controls the expression of the divergently transcribed nagE‐nagBACD operons involved in the uptake and degradation of the amino sugars, N‐acetyl‐D‐glucosamine (GlcNAc) and glucosamine (GlcN). The glmUS operon, encoding proteins necessary for the synthesis of GlcN (glmS) and the formation of UDP‐GlcNAc (glmU), is transcribed from two promoters located upstream of glmU. In the absence of amino sugars both promoters are active. However, in the presence of GlcNAc, the glmU proximal promoter, P1, is inactive while the upstream promoter, P2, is subject to weak induction. Two binding sites for the NagC repressor are located at −200 and −47 bp upstream of P1. Mutations which prevent NagC binding to either of these sites eliminate expression from the P1 promoter. This shows that binding of NagC is necessary for expression of the glmU P1 promoter and implies that NagC is playing the role of activator for this promoter. Moreover, the location of the distal NagC site suggests that this site is behaving like an upstream activating sequence (UAS).

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In vivo requirement of integration host factor for nar (nitrate reductase) operon expression in Escherichia coli K-12.

Cited by 44 publications

References 43 publications

Integration host factor is required for anaerobic pyruvate induction of pfl operon expression in Escherichia coli

Integration host factor is required for anaerobic pyruvate induction of pfl operon expression in Escherichia coli

Periplasmic Nitrate Reductase (NapABC Enzyme) Supports Anaerobic Respiration byEscherichia coliK-12

Co-ordinated regulation of amino sugar biosynthesis and degradation: the NagC repressor acts as both an activator and a repressor for the transcription of the glmUS operon and requires two separated NagC binding sites.

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