Genetic regulation of nitrogen fixation in rhizobia.

Fischer, Hans‐Martin

doi:10.1128/mmbr.58.3.352-386.1994

Cited by 457 publications

(293 citation statements)

References 259 publications

(415 reference statements)

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“…However, exhaustive inspection of the nap, nir or nor promoter regions failed to reveal an upstream activator sequence, i.e. the binding site for the transcriptional activator protein, NifA, which is present in most NifA-dependent promoters between 80 and 150 nucleotides upstream of the transcriptional start site (Fischer, 1994). As expected, neither nucleotide sequence with the -24/-12 regions corresponding to the RpoN-dependent promoters was present in any of the denitrification gene promoter regions.…”

Section: Transcription Analysis Of the Nirk Genementioning

confidence: 99%

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NifA is required for maximal expression of denitrification genes in Bradyrhizobium japonicum

Cendejas-Bueno

Mesa

Sánchez

et al. 2010

Environmental Microbiology

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In Bradyrhizobium japonicum the napEDABC, nirK, norCBQD and nosRZDYFLX genes, which encode reductases for nitrate, nitrite, nitric oxide and nitrous oxide, respectively, are required for denitrification. Microaerobic induction of these genes depends on fixLJ and fixK2, whose products form the FixLJ-FixK2 regulatory cascade. In B. japonicum, a second oxygen-responsive regulatory cascade mediated by the nitrogen fixation regulatory protein, NifA, has been described. In this study, we show that disruption of nifA caused a growth defect in B. japonicum cells, when grown under denitrifying conditions, and decreased activity of periplasmic nitrate and nitrite reductase enzymes was also observed. Furthermore, expression of napE-lacZ, nirK-lacZ or norC-lacZ transcriptional fusions, as well as levels of nirK transcripts were significantly reduced in the nifA mutant after incubation under nitrate-respiring conditions. Haem c staining analyses revealed that NifA is required for full synthesis of the NapC and NorC proteins, which are required for denitrification. A B. japonicum rpoN1/2 mutant, lacking both copies of the gene encoding the alternative sigma factor sigma54, was able to grow anaerobically with nitrate as terminal electron acceptor and showed wild-type levels of nitrate and nitrite reductase activities. We propose that the nitrogen fixation regulatory protein, NifA, is involved in the maximal expression of the denitrification genes in B. japonicum. This influence is independent of sigma54.

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Section: Transcription Analysis Of the Nirk Genementioning

confidence: 99%

“…groESL3) or have unknown function in this process (e.g. nrgA, nrgBC) (Fischer, 1994;Nienaber et al, 2000). Microarray based experiments have led to a substantial expansion of the NifA regulon, revealing a total of 65 genes for nitrogen fixation and other diverse processes (Hauser et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

NifA is required for maximal expression of denitrification genes in Bradyrhizobium japonicum

Cendejas-Bueno

Mesa

Sánchez

et al. 2010

Environmental Microbiology

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“…The NifA protein activates the transcription of c x -dependent nif and other promoters [6] and it also activates the Rhizobium meliloti and Bradyrhizobium japonicum ¢xABCX genes [7,8]. The NifA proteins have a modular structure typical of c x -dependent promoter-activating proteins.…”

Section: Introductionmentioning

confidence: 99%

Expression and functional analysis of an N‐truncated NifA protein of Herbaspirillum seropedicae

et al. 1999

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In Herbaspirillum seropedicae, an endophytic diazotroph, nif gene expression is under the control of the transcriptional activator NifA. We have over-expressed and purified a protein containing the central and C-terminal domains of the H. seropedicae NifA protein, N-truncated NifA, fused to a His-Tag sequence. This fusion protein was found to be partially soluble and was purified by affinity chromatography. Band shift and footprinting assays showed that the N-truncated NifA protein was able to bind specifically to the H. seropedicae nifB promoter region. In vivo analysis showed that this protein activated the nifH promoter of Klebsiella pneumoniae in Escherichia coli only in the absence of oxygen and this activation was not negatively controlled by ammonium ions.z 1999 Federation of European Biochemical Societies.

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“…Prototypes of the 0Cys variants are represented by FixK 2 of Rhodopseudomonas japonicum and FixK of Rhizobium meliloti (Batut et al, 1989;Fischer, 1994). FixK 2 and FixK are part of an O 2 -regulatory cascade, which induces nitrogen fixation and nitrate respiratory genes under anoxic conditions.…”

Section: Cys Variants Of Fnr-ecmentioning

confidence: 99%

Origin and phylogenetic relationships of [4Fe–4S]‐containing O₂ sensors of bacteria

Barth

Weiss

Roettger

et al. 2018

Environmental Microbiology

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The advent of environmental O about 2.5 billion years ago forced microbes to metabolically adapt and to develop mechanisms for O sensing. Sensing of O by [4Fe-4S] to [2Fe-2S] cluster conversion represents an ancient mechanism that is used by FNR (Escherichia coli), FNR (Bacillus subtilis), NreB (Staphylococcus aureus) and WhiB3 (Mycobacterium tuberculosis). The phylogenetic relationship of these sensors was investigated. FNR homologues are restricted to the proteobacteria and a few representatives from other phyla. Homologues of FNR and NreB are located within the bacilli, of WhiB3 within the actinobacteria. Archaea contain no homologues. The data reveal no similarity between the FNR , FNR , NreB and WhiB3 sensor families on the sequence and structural levels. These O sensor families arose independently in phyla that were already present at the time O appeared, their members were subsequently distributed by lateral gene transfer. The chemistry of [4Fe-4S] and [2Fe-2S] cluster formation and interconversion appears to be shared by the sensor protein families. The type of signal output is, however, family specific. The homologues of FNR and NreB vary with regard to the number of Cys residues that coordinate the cluster. It is suggested that the variants derive from lateral gene transfer and gained other functions.

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Genetic regulation of nitrogen fixation in rhizobia.

Cited by 457 publications

References 259 publications

NifA is required for maximal expression of denitrification genes in Bradyrhizobium japonicum

NifA is required for maximal expression of denitrification genes in Bradyrhizobium japonicum

Expression and functional analysis of an N‐truncated NifA protein of Herbaspirillum seropedicae

Origin and phylogenetic relationships of [4Fe–4S]‐containing O₂ sensors of bacteria

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Genetic regulation of nitrogen fixation in rhizobia.

Cited by 457 publications

References 259 publications

NifA is required for maximal expression of denitrification genes in Bradyrhizobium japonicum

NifA is required for maximal expression of denitrification genes in Bradyrhizobium japonicum

Expression and functional analysis of an N‐truncated NifA protein of Herbaspirillum seropedicae

Origin and phylogenetic relationships of [4Fe–4S]‐containing O2 sensors of bacteria

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Origin and phylogenetic relationships of [4Fe–4S]‐containing O₂ sensors of bacteria