Regulation of Nitrogen Fixation in Free-Living Diazotrophs

Merrick, Mike

doi:10.1007/1-4020-2179-8_9

Cited by 53 publications

(85 citation statements)

References 166 publications

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“…However, whether PI, is also involved in the ADPribosylation of glutamine synthetase (Woehle e t al., 1990) remains to be established. The sequence of glnBp2, the putative aS4-dependent promoter, TGGCACGN,GTGAT, is 75 9'0 similar to the consensus TGGCACGN,TTGCA (Merrick, 1992) but it is localized at -13/ -25 bp from the transcription start site instead of the usual -12/-24.…”

Section: Discussionmentioning

confidence: 99%

Transcription of the glnB and glnA genes in the photosynthetic bacterium Rhodospirillum rubrum

Johansson

Nordlund

1996

Microbiology

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The PI, protein, encoded by glnB, has a central role in the control of nitrogen metabolism in nitrogen-fixing prokaryotes. The glnle gene of Rhodospirillum rubrum was isolated and sequenced. The deduced amino acid sequence had very high sequence identity to other PI, proteins. The glnA gene, encoding glutamine synthetase, was located 135 bp downstream of glnle and was partially sequenced. glnB is cotranscribed with glnA from a promoter with high similarity to the a5*-dependent promoter consensus sequence. A putative o 7 O promoter was also identified further upstream of glnB. Northern blotting analyses showed that in addition glnA is either transcribed from an unidentified promoter or, more likely, that the ghBA transcript is processed to give the glnA mRNA. The total level of the two transcripts was much higher in nitrogen-f ixing cells than in ammonia-grown cells.

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Section: Discussionmentioning

confidence: 99%

Transcription of the glnB and glnA genes in the photosynthetic bacterium Rhodospirillum rubrum

Johansson

Nordlund

1996

Microbiology

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“…In diazotrophs of the ␣ and ␥ proteobacteria, nif gene transcription is initiated at 54 -dependent promoters in conjunction with a specific transcriptional activator, NifA (51,59,154). Control of nif transcription is mediated by regulating either the expression or the activity of NifA in response to oxygen and fixed nitrogen.…”

Section: Regulation Of Nitrogen Fixationmentioning

confidence: 99%

P_IISignal Transduction Proteins, Pivotal Players in Microbial Nitrogen Control

Arcondéguy

Jack

Merrick

2001

Microbiol Mol Biol Rev

395

456

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SUMMARY The PII family of signal transduction proteins are among the most widely distributed signal proteins in the bacterial world. First identified in 1969 as a component of the glutamine synthetase regulatory apparatus, PII proteins have since been recognized as playing a pivotal role in control of prokaryotic nitrogen metabolism. More recently, members of the family have been found in higher plants, where they also potentially play a role in nitrogen control. The PII proteins can function in the regulation of both gene transcription, by modulating the activity of regulatory proteins, and the catalytic activity of enzymes involved in nitrogen metabolism. There is also emerging evidence that they may regulate the activity of proteins required for transport of nitrogen compounds into the cell. In this review we discuss the history of the PII proteins, their structures and biochemistry, and their distribution and functions in prokaryotes. We survey data emerging from bacterial genome sequences and consider other likely or potential targets for control by PII proteins.

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“…The sequence, T G T (N,,)ACA, centred about 157 bases upstream of the nifH translational start codon (Fig. l a ) , but downstream of the transcript start site, is identical to the consensusbinding sequence [TGT(N,,)ACA] for the product of nifA (Dixon et al, 1987;Merrick, 1992). There are regions of DNA sequence that may form stem-loop structures in the mRNA.…”

Section: Dna Sequence Analysismentioning

confidence: 99%

“…The RpoN-dependent promoters usually have a highly conserved -24, -12 sequence, instead of the consensus sequence located around positions -35 and -10 recognized by a" and most other t s factors (Merrick, 1992). Activation of nif promoters in many non-cyanobacterial diazotrophs is NifA dependent (Merrick, 1992).…”

Section: Introductionmentioning

confidence: 99%

Cloning and transcriptional analysis of the nifUHDK genes of Trichodesmium sp. IMS101 reveals stable nifD, nifDK and nifK transcripts

Dominic¹,

Chen²,

Zehr³

1998

Microbiology

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Trichodesmium spp. are marine filamentous, non-heterocystous cyanobacteria capable of aerobic nitrogen fixation. In this study, the nitrogenase structural genes (nifHDK) and nifU gene of Trichodesmium sp. I M S l O l were cloned and sequenced. The Trichodesmium sp. I M S l O l nifH, nifD and nifK amino acid sequences showed only 79%, 66% and 68% identity, respectively, to those of Anabaena sp. strain PCC 7120. A potential transcription start site for nifH was found 212 bases upstream of the nifH start codon. Promoter-like nucleotide sequences upstream of the transcription start site were identified that were very similar to those identified for the nitrogenase genes of Anabaena spp. Sequence analysis revealed regions of DNA that may form stem-loop structures in the intercistronic regions downstream of nifH and nifD, RNA analysis by Northern hybridization revealed the presence of transcripts corresponding to nifH, nifHD and nifHDK. Surprisingly, Northern hybridization also revealed the presence of transcripts that corresponded to nifD, nifDK and nifK, which have not been previously reported as transcripts in contiguous nifHDK genes of cyanobacteria. Transcription of the nifHDK genes was not significantly repressed in the presence of nitrate a t a final concentration of 20 mM or a t oxygen concentrations of up to 40%, whereas ammonium and urea inhibited nifHDK transcription. The transcription of the nifHDK genes was not affected by darkness, which suggests that transcription of these genes in Trichodesmium is not directly regulated by light.

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Regulation of Nitrogen Fixation in Free-Living Diazotrophs

Cited by 53 publications

References 166 publications

Transcription of the glnB and glnA genes in the photosynthetic bacterium Rhodospirillum rubrum

Transcription of the glnB and glnA genes in the photosynthetic bacterium Rhodospirillum rubrum

P_IISignal Transduction Proteins, Pivotal Players in Microbial Nitrogen Control

Cloning and transcriptional analysis of the nifUHDK genes of Trichodesmium sp. IMS101 reveals stable nifD, nifDK and nifK transcripts

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Regulation of Nitrogen Fixation in Free-Living Diazotrophs

Cited by 53 publications

References 166 publications

Transcription of the glnB and glnA genes in the photosynthetic bacterium Rhodospirillum rubrum

Transcription of the glnB and glnA genes in the photosynthetic bacterium Rhodospirillum rubrum

PIISignal Transduction Proteins, Pivotal Players in Microbial Nitrogen Control

Cloning and transcriptional analysis of the nifUHDK genes of Trichodesmium sp. IMS101 reveals stable nifD, nifDK and nifK transcripts

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P_IISignal Transduction Proteins, Pivotal Players in Microbial Nitrogen Control