Identification of a <i>cis</i>‐acting element in nitrogen fixation genes recognized by CnfR in the nonheterocystous nitrogen‐fixing cyanobacterium <i>Leptolyngbya boryana</i>

Tsujimoto, Ryoma; Kamiya, Narumi; Fujita, Yuichi

doi:10.1111/mmi.13402

Cited by 24 publications

(40 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Tsujimoto et al (25) drew very different conclusions from their data on the importance of the homologs of CS1, CS2, and CS3 of L. boryana for transcriptional activation of nifB by CnfR. Using Synechocystis sp.…”

Section: Discussionmentioning

confidence: 99%

“…An interaction between CnfR and these conserved nifB sequences has been implicated in the nonheterocystous cyanobacterium Leptolyngbya boryana (25), and direct binding of CnfR to the conserved sequences upstream of nifB was shown for CnfR from the unicellular nitrogen-fixing strain Cyanothece sp. strain ATCC 51142 (34).…”

Section: Discussionmentioning

confidence: 99%

“…Further, while the loss of CS3 had no effect on nifB1 expression in A. variabilis, CS3 was essential for expression of nifB from L. boryana in Synechocystis sp. PCC 6803 (25). To further complicate the interpretation of the role of CS1, CS2, and CS3 in nifB expression, Balassy and Zhang have provisionally shown, also using Synechocystis sp.…”

Section: Discussionmentioning

confidence: 99%

“…In A. variabilis, as well as in L. boryana (25) and in Cyanothece (34), there are interactions between highly conserved sequences upstream of nifB1 and nifB2 with their cognate activator proteins, CnfR1 and CnfR2, respectively. These interactions induce expression of each nifB gene.…”

Section: Discussionmentioning

confidence: 99%

“…Transcription of nifB, the first gene in the large cluster of genes that is responsible for the synthesis of nitrogenase, requires an activator protein, CnfR (originally called PatB) (26)(27)(28)(29), and also depends on highly conserved sequences upstream of the nifB transcription start site (25). An interaction between CnfR and these conserved nifB sequences has been implicated in the nonheterocystous cyanobacterium Leptolyngbya boryana (25), and direct binding of CnfR to the conserved sequences upstream of nifB was shown for CnfR from the unicellular nitrogen-fixing strain Cyanothece sp.…”

Section: Discussionmentioning

confidence: 99%

See 4 more Smart Citations

Role of the nifB1 and nifB2 Promoters in Cell-Type-Specific Expression of Two Mo Nitrogenases in the Cyanobacterium Anabaena variabilis ATCC 29413

2017

View full text Add to dashboard Cite

Anabaena variabilis ATCC 29413 has one Mo nitrogenase that is made under oxic growth conditions in specialized cells called heterocysts and a second Mo nitrogenase that is made only under anoxic conditions in vegetative cells. The two large nif gene clusters responsible for these two nitrogenases are under the control of the promoter of the first gene in the operon, nifB1 or nifB2. Despite differences in the expression patterns of nifB1 and nifB2, related to oxygen and cell type, the regions upstream of their transcription start sites (tss) show striking homology, including three highly conserved sequences (CS). CS1, CS2, and the region just upstream from the tss were required for optimal expression from the nifB1 promoter, but CS3 and the 5= untranslated region (UTR) were not. Hybrid fusions of the nifB1 and nifB2 upstream regions revealed that the region including CS1, CS2, and CS3 of nifB2 could substitute for the similar region of nifB1; however, the converse was not true. Expression from the nifB2 promoter region required the CS1, CS2, and CS3 regions of nifB2 and also required the nifB2 5= UTR. A hybrid promoter that was mostly nifB2 but that had the region from about position Ϫ40 to the tss of nifB1 was expressed in heterocysts and in anoxic vegetative cells. Thus, addition of the nifB1 promoter region (from about position Ϫ40 to the tss of nifB1) in the nifB hybrid promoter supported expression in heterocysts but did not prevent the mostly nifB2 promoter from also functioning in anoxic vegetative cells. IMPORTANCE In the filamentous cyanobacterium Anabaena variabilis, two Mo nitrogenase gene clusters, nif1 and nif2, function under different environmental conditions in different cell types. Little is known about the regulation of transcription from the promoter upstream of the first gene of the cluster, which drives transcription of each of these two large operons. The similarity in the sequences upstream of the primary promoters for the two nif gene clusters belies the differences in their expression patterns. Analysis of these nif promoters in strains with mutations in the conserved sequences and in strains with hybrid promoters, comprising parts from nif1 and nif2, provides strong evidence that each promoter has key elements required for cell-type-specific expression of the nif1 and nif2 gene clusters.KEYWORDS Anabaena, cyanobacteria, heterocysts, nitrogenase, regulation, transcriptional regulation F ilamentous heterocystous cyanobacteria fix atmospheric nitrogen under oxic growth conditions in specialized cells called heterocysts that differentiate in a semiregular pattern in a filament. They comprise about 5 to 10% of the cells in filaments in cultures grown in an environment that is deficient in fixed nitrogen (1-5). Heterocysts are microoxic; they have a glycolipid layer that restricts oxygen diffusion into the cell, lack components of oxygen-evolving photosystem II, and have high levels of respiration, which together protect the oxygen-labile nitrogenase from oxygen (6-10).

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Role of the nifB1 and nifB2 Promoters in Cell-Type-Specific Expression of Two Mo Nitrogenases in the Cyanobacterium Anabaena variabilis ATCC 29413

2017

View full text Add to dashboard Cite

show abstract

In vivo transposon tagging in the nonheterocystous nitrogen‐fixing cyanobacterium Leptolyngbya boryana

et al. 2018

Self Cite

View full text Add to dashboard Cite

Nitrogenase is an oxygen-vulnerable metalloenzyme that catalyzes nitrogen fixation. It largely remains unknown how nitrogenase coexists with oxygenic photosynthesis in nonheterocystous cyanobacteria, since there have been no appropriate model cyanobacteria so far. Here, we demonstrate in vivo transposon tagging in the nonheterocystous cyanobacterium Leptolyngbya boryana as a forward genetics approach. By conjugative transfer, a mini-Tn5-derived vector, pKUT-Tn5-Sm/Sp, was transferred from Escherichia coli to L. boryana cells. Of 1839 streptomycin-resistant colonies, we isolated three mutants showing aberrant diazotrophic growth. Genome resequencing identified the insertion sites of the transposon in the mutants. This in vivo transposon tagging mutagenesis of L. boryana provides a promising system to investigate molecular mechanisms to resolve the Oxygen Paradox between nitrogen fixation and oxygenic photosynthesis in cyanobacteria.

show abstract

Soil type and moisture content alter soil microbial responses to manure from cattle administered antibiotics

Shawver,

Ishii,

Strickland

et al. 2024

Environ Sci Pollut Res

View full text Add to dashboard Cite

Growing concerns about the global antimicrobial resistance crisis require a better understanding of how antibiotic resistance persists in soil and how antibiotic exposure impacts soil microbial communities. In agroecosystems, these responses are complex because environmental factors may influence how soil microbial communities respond to manure and antibiotic exposure. The study aimed to determine how soil type and moisture alter responses of microbial communities to additions of manure from cattle treated with antibiotics. Soil microcosms were constructed using two soil types at 15, 30, or 45% moisture. Microcosms received biweekly additions of manure from cattle given cephapirin or pirlimycin, antibiotic-free manure, or no manure. While soil type and moisture had the largest effects on microbiome structure, impacts of manure treatments on community structure and individual ARG abundances were observed across varying soil conditions. Activity was also affected, as respiration increased in the cephapirin treatment but decreased with pirlimycin. Manure from cattle antibiotics also increased NH4+ and decreased NO3− availability in some scenarios, but the effects were heavily influenced by soil type and moisture. Overall, this work demonstrates that environmental conditions can alter how manure from cattle administered antibiotics impact the soil microbiome. A nuanced approach that considers environmental variability may benefit the long-term management of antibiotic resistance in soil systems.

show abstract

Identification of a cis‐acting element in nitrogen fixation genes recognized by CnfR in the nonheterocystous nitrogen‐fixing cyanobacterium Leptolyngbya boryana

Cited by 24 publications

References 49 publications

Role of the nifB1 and nifB2 Promoters in Cell-Type-Specific Expression of Two Mo Nitrogenases in the Cyanobacterium Anabaena variabilis ATCC 29413

Role of the nifB1 and nifB2 Promoters in Cell-Type-Specific Expression of Two Mo Nitrogenases in the Cyanobacterium Anabaena variabilis ATCC 29413

In vivo transposon tagging in the nonheterocystous nitrogen‐fixing cyanobacterium Leptolyngbya boryana

Soil type and moisture content alter soil microbial responses to manure from cattle administered antibiotics

Contact Info

Product

Resources

About