Glucose repression of anaerobic genes of Escherichia coli is independent of cyclic AMP

Reams, Stephen G.

doi:10.1016/0378-1097(88)90196-6

Cited by 4 publications

(4 citation statements)

References 18 publications

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“…Current evidence suggests that glucose and cAMP have only small and possibly indirect effects on the expression of the fnr gene and fnr-regulated genes [2]. In fact, the role of cAMP in anaerobic metabolism is not fully understood and there is some evidence to sug£est that the glucose repression of anaerobic genes is independent of cAMP [144]. Other potential nucleotide cocffectors include NADH or acyl-CoA.…”

Section: The Oxygen-sensing Meci-l~nism Of Fnrmentioning

confidence: 99%

FNR and its role in oxygen-regulated gene expression in Escherichia coli

Spiro

1990

FEMS Microbiology Letters

205

306

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Bacteria which can grow in different environments have developed regulatory systems which allow them to exploit specific habitats to their best advantage. In the facultative anaerobe Escherichia coli two transcriptional regulators controlling independent networks of oxygen‐regulated gene expression have been identified. One is a two‐component sensor‐regulator system (ArcB‐A), which represses a wide variety of aerobic enzymes under anaerobic conditions. The other is FNR, the transcriptional regulator which is essential for expressing anaerobic respiratory processes. The purpose of this review is to summarize what is known about FNR. The fnr gene was initially defined by the isolation of some pleiotropic mutants which characteristically lacked the ability to use fumarate and nitrate as reducible substrates for supporting anaerobic growth and several other anaerobic respiratory functions. Its role as a transcripitonal regulator emerged from genetic and molecular studies in which its homology with CRP (the cyclic AMP receptor protein which mediates catabolite repression) was established and has since been particularly important in identifying the structural basis of its regulatory specificities. FNR is a member of a growing family of CRP‐related regulatory proteins which have a DNA‐binding domain based on the helix‐turn‐helix structural motif, and a characteristic β‐roll that is involved in nucleotide‐binding in CRP. The FNR protein has been isolated in a monomeric form (Mr 30 000) which exhibits a high but as yet non‐specific affinity for DNA. Nevertheless, the DNA‐recognition site and important residues conferring the functional specificity of FNR have been defined by site‐directed mutagenesis. A consensus for the sequences that are recognized by FNR in the promoter regions of FNR‐regulated genes, has likewise been identified. The basic features of genes and operons regulated by FNR are reviewed, and examples in which FNR functions negatively as an anaerobic repressor as well as positively as an anaerobic activator, are included. Less is known about the way in which FNR senses anoxia and is thereby transformed into its ‘active’s form, but it seems likely that It is clear that oxygen functions as a regulatory signal controlling several important aspects of mitcrobial physiology, and further studies should reveal the molecular basis of the mechanism by which changes in oxygen tension are sensed. The recent identification of FNR homologues in diverse microorganisms points to the widespread importance of this family of regulatory proteins. Moreover, the function of these proteins is not limited to the regulation of anaerobic respiration but includes roles in the regulation of nitrogen fixation and haemolysin biosynthesis. The ability to over‐ride these regulatory mechanisms may have useful biotechnological applications, and it could also be important in controlling pathogenesis. It is anticipated that further studies will provide insights into the way in which these regulatory proteins with common evolut...

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Section: The Oxygen-sensing Meci-l~nism Of Fnrmentioning

confidence: 99%

FNR and its role in oxygen-regulated gene expression in Escherichia coli

Spiro

1990

FEMS Microbiology Letters

205

306

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“…This induction is prevented in anaerobically grown cells exposed to glucose. There is a report of studies on this enzyme in which a lacZ fusion was used (256). The response of alcohol dehydrogenase to glucose is independent of cAMP.…”

Section: Complex Control Systems Involving Crp-campmentioning

confidence: 99%

Cyclic AMP in prokaryotes.

Botsford

Harman

1992

Microbiological Reviews

424

212

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“…Interestingly, swarming of wild-type strain HI4320 was inhibited when 0.02% (wt/vol) glucose was added to LB-1.5% agar containing NaN 3 ( Fig. 5B ), suggesting that in the presence of glucose, which promotes aerobic respiration when oxygen is present ( 22 ), P. mirabilis is unable to use its apparently preferred anaerobic-like electron acceptor and energy pathway required for swarming. The activity of azide on swarming was specific for membrane respiration with oxygen rather than acting as an uncoupler, because P. mirabilis was unable to swarm when the proton gradient was collapsed by adding the conventional uncoupler carbonylcyanide m-chlorophenylhydrazone (CCCP) to LB-1.5% agar (data not shown).…”

Section: Resultsmentioning

confidence: 99%

Anaerobic Respiration Using a Complete Oxidative TCA Cycle Drives Multicellular Swarming in Proteus mirabilis

Alteri

Himpsl

Engstrom

et al. 2012

mBio

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Proteus mirabilis rapidly migrates across surfaces using a periodic developmental process of differentiation alternating between short swimmer cells and elongated hyperflagellated swarmer cells. To undergo this vigorous flagellum-mediated motility, bacteria must generate a substantial proton gradient across their cytoplasmic membranes by using available energy pathways. We sought to identify the link between energy pathways and swarming differentiation by examining the behavior of defined central metabolism mutants. Mutations in the tricarboxylic acid (TCA) cycle (fumC and sdhB mutants) caused altered patterns of swarming periodicity, suggesting an aerobic pathway. Surprisingly, the wild-type strain swarmed on agar containing sodium azide, which poisons aerobic respiration; the fumC TCA cycle mutant, however, was unable to swarm on azide. To identify other contributing energy pathways, we screened transposon mutants for loss of swarming on sodium azide and found insertions in the following genes that involved fumarate metabolism or respiration: hybB, encoding hydrogenase; fumC, encoding fumarase; argH, encoding argininosuccinate lyase (generates fumarate); and a quinone hydroxylase gene. These findings validated the screen and suggested involvement of anaerobic electron transport chain components. Abnormal swarming periodicity of fumC and sdhB mutants was associated with the excretion of reduced acidic fermentation end products. Bacteria lacking SdhB were rescued to wild-type pH and periodicity by providing fumarate, independent of carbon source but dependent on oxygen, while fumC mutants were rescued by glycerol, independent of fumarate only under anaerobic conditions. These findings link multicellular swarming patterns with fumarate metabolism and membrane electron transport using a previously unappreciated configuration of both aerobic and anaerobic respiratory chain components.

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Glucose repression of anaerobic genes of Escherichia coli is independent of cyclic AMP

Cited by 4 publications

References 18 publications

FNR and its role in oxygen-regulated gene expression in Escherichia coli

FNR and its role in oxygen-regulated gene expression in Escherichia coli

Cyclic AMP in prokaryotes.

Anaerobic Respiration Using a Complete Oxidative TCA Cycle Drives Multicellular Swarming in Proteus mirabilis

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