Two heterocyst-specific DNA rearrangements of nif operons in Anabaena cylindrica and Nostoc sp. strain Mac

Carrasco, Claudio D.; Golden, James W.

doi:10.1099/13500872-141-10-2479

Cited by 27 publications

(16 citation statements)

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“…The first data on cyanobacterial hupSL transcription appeared in 1995 (Carrasco & Golden, 1995). RT-PCR experiments on Anabaena/Nostoc sp.…”

Section: Introductionmentioning

confidence: 99%

“…All cyanobacteria examined so far contain an uptake, a bi-directional or both the hydrogenases (Schmitz et al, 1995(Schmitz et al, , 2002Boison et al, 1996;Tamagnini et al, 2000Tamagnini et al, , 2002Sheremetieva et al, 2002; Schütz et al, 2004). Moreover, the uptake-type enzyme has been found in all nitrogen fixing cyanobacterial strains studied to date (Carrasco & Golden, 1995;Oxelfelt et al, 1998;Happe et al, 2000;Tamagnini et al, 2000Tamagnini et al, , 2002 Schütz et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Characterization and transcriptional analysis of hupSLW in Gloeothece sp. ATCC 27152: an uptake hydrogenase from a unicellular cyanobacterium

et al. 2004

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The structural genes (hupSL) encoding an uptake hydrogenase in the unicellular cyanobacterium Gloeothece sp. ATCC 27152, a strain capable of aerobic N 2 fixation, were identified and sequenced. 39-RACE experiments uncovered the presence of an additional ORF 184 bp downstream of hupL, showing a high degree of sequence identity with a gene encoding an uptake-hydrogenase-specific endopeptidase (hupW ) in other cyanobacteria. In addition, the transcription start point was identified 238 bp upstream of the hupS translational start. RT-PCR experiments revealed that hupW is co-transcribed with the uptake hydrogenase structural genes in Gloeothece sp. ATCC 27152. In addition, Northern hybridizations clearly showed that hupSLW are transcribed under nitrogen fixing conditions, but not in the presence of combined nitrogen. A putative NtcA binding site was identified in the promoter region upstream of hupS, centred at "41?5 bp with respect to the transcription start point. Electrophoretic retardation of a labelled DNA fragment (harbouring the putative NtcA-binding motif) was significantly affected by an Escherichia coli cell-free extract containing overexpressed NtcA, suggesting that NtcA is involved in the transcriptional regulation of hupSLW. INTRODUCTIONSeveral species of bacteria and cyanobacteria are capable of N 2 fixation. During the N 2 fixation process H 2 is formed as a by-product. This nitrogenase-dependent H 2 production is often compromised by the presence of an uptake hydrogenase (encoded by hupSL) that rapidly consumes the H 2 generated. In addition, a bi-directional enzyme (encoded by hoxEFUYH) may be present which, depending on the growth conditions, may display the capacity of both producing and consuming H 2 (Lambert & Smith, 1981;Houchins, 1984;Schmitz et al., 2002;Tamagnini et al., 2002). All cyanobacteria examined so far contain an uptake, a bi-directional or both the hydrogenases (Schmitz et al., 1995(Schmitz et al., , 2002Boison et al., 1996;Tamagnini et al., 2000Tamagnini et al., , 2002Sheremetieva et al., 2002; Schütz et al., 2004). Moreover, the uptake-type enzyme has been found in all nitrogen fixing cyanobacterial strains studied to date (Carrasco & Golden, 1995;Oxelfelt et al., 1998;Happe et al., 2000;Tamagnini et al., 2000Tamagnini et al., , 2002 Schütz et al., 2004).The first data on cyanobacterial hupSL transcription appeared in 1995 (Carrasco & Golden, 1995). RT-PCR experiments on Anabaena/Nostoc sp. strain PCC 7120 demonstrated that hupL transcription coincides with the formation of heterocysts. Subsequent studies, in other filamentous strains, have confirmed the induction of an hupL transcript under nitrogen-fixing conditions only (Axelsson et al., 1999;Happe et al., 2000; Hansel et al., 2001). One exception is Anabaena variabilis ATCC 29413, where a low level of hupL expression has been detected in vegetative cells grown with the addition of ammonia (Boison et al., 2000). In all the cyanobacterial strains 3Present address: Department of Physiological Botany, Evolutionary Biology Centre,...

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“…The first data on cyanobacterial hupSL transcription appeared in 1995 (Carrasco & Golden, 1995). RT-PCR experiments on Anabaena/Nostoc sp.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization and transcriptional analysis of hupSLW in Gloeothece sp. ATCC 27152: an uptake hydrogenase from a unicellular cyanobacterium

et al. 2004

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“…The nifD and fdxN elements in Anabaena cylindrica and a Fox ϩ revertant of Nostoc strain Mac were shown to undergo rearrangement during heterocyst differentiation (7). For the hupL element, DNA hybridization studies suggested that the element was present in half of the filamentous strains tested (40); however, the hupL element is absent from two strains for which genome sequences are available, Anabaena variabilis (20) and Nostoc punctiforme (31).…”

mentioning

confidence: 99%

“…At least eight strains of Anabaena or Nostoc contain a nifD element, and three strains are known to contain an fdxN element (7,22). The nifD and fdxN elements in Anabaena cylindrica and a Fox ϩ revertant of Nostoc strain Mac were shown to undergo rearrangement during heterocyst differentiation (7).…”

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Heterocyst-Specific Excision of the Anabaena sp. Strain PCC 7120 hupL Element Requires xisC

et al. 2005

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In nitrogen-limiting conditions, approximately 10% of the vegetative cells in filaments of the cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 differentiate into nitrogen-fixing heterocysts. During the late stages of heterocyst differentiation, three DNA elements, each embedded within an open reading frame, are programmed to excise from the chromosome by site-specific recombination. The DNA elements are named after the genes that they interrupt: nifD, fdxN, and hupL. The nifD and fdxN elements each contain a gene, xisA or xisF, respectively, that encodes the site-specific recombinase required for programmed excision of the element. Here, we show that the xisC gene (alr0677), which is present at one end of the 9,435-bp hupL element, is required for excision of the hupL element. A strain in which the xisC gene was inactivated showed no detectable excision of the hupL element. hupL encodes the large subunit of uptake hydrogenase. The xisC mutant forms heterocysts and grows diazotrophically, but unlike the wild type, it evolved hydrogen gas under nitrogen-fixing conditions. Overexpression of xisC from a plasmid in a wild-type background caused a low level of hupL rearrangement even in nitrogen-replete conditions. Expression of xisC in Escherichia coli was sufficient to produce rearrangement of an artificial substrate plasmid bearing the hupL element recombination sites. Sequence analysis indicated that XisC is a divergent member of the phage integrase family of recombinases. Site-directed mutagenesis of xisC showed that the XisC recombinase has functional similarity to the phage integrase family.

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Iron Homeostasis and Environmental Responses in Cyanobacteria: Regulatory Networks Involving Fur

Peleato

Bes

Fillat

2016

Stress and Environmental Regulation of Gene Expression and Adaptation in Bacteria

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Two heterocyst-specific DNA rearrangements of nif operons in Anabaena cylindrica and Nostoc sp. strain Mac

Cited by 27 publications

References 31 publications

Characterization and transcriptional analysis of hupSLW in Gloeothece sp. ATCC 27152: an uptake hydrogenase from a unicellular cyanobacterium

Characterization and transcriptional analysis of hupSLW in Gloeothece sp. ATCC 27152: an uptake hydrogenase from a unicellular cyanobacterium

Heterocyst-Specific Excision of the Anabaena sp. Strain PCC 7120 hupL Element Requires xisC

Iron Homeostasis and Environmental Responses in Cyanobacteria: Regulatory Networks Involving Fur

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