scholarly journals patD, a Gene Regulated by NtcA, Is Involved in the Optimization of Heterocyst Frequency in the Cyanobacterium Anabaena sp. Strain PCC 7120

2019 ◽  
Vol 201 (21) ◽  
Author(s):  
Li Wang ◽  
Gui-Ming Lin ◽  
Tian-Cai Niu ◽  
Shao-Ran Zhang ◽  
Ju-Yuan Zhang ◽  
...  
Keyword(s):  
Carbon Fixation ◽  
Optimal Growth ◽  
Term Survival ◽  
Vegetative Cells ◽  
Carbon And Nitrogen ◽  
Competitive Edge ◽  
Heterocyst Frequency ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120

ABSTRACT In the filamentous multicellular cyanobacterium Anabaena sp. strain PCC 7120, 5 to 10% of the cells differentiate into heterocysts, which are specialized in N2 fixation. Heterocysts and vegetative cells are mutually dependent for filament growth through nutrient exchange. Thus, the heterocyst frequency should be optimized to maintain the cellular carbon and nitrogen (C/N) balance for filament fitness in the environment. Here, we report the identification of patD, whose expression is directly activated in developing cells by the transcription factor NtcA. The inactivation of patD increases heterocyst frequency and promotes the upregulation of the positive regulator of heterocyst development hetR, whereas its overexpression decreases the heterocyst frequency. The change in heterocyst frequency resulting from the inactivation of patD leads to the reduction in competitiveness of the filaments under combined-nitrogen-depleted conditions. These results indicate that patD regulates heterocyst frequency in Anabaena sp. PCC 7120, ensuring its optimal filament growth. IMPORTANCE Microorganisms have evolved various strategies in order to adapt to the environment and compete with other organisms. Heterocyst differentiation is a prokaryotic model for studying complex cellular regulation. The NtcA-regulated gene patD controls the ratio of heterocysts relative to vegetative cells on the filaments of Anabaena sp. strain PCC 7120. Such a regulation provides a mechanism through which carbon fixation by vegetative cells and nitrogen fixation by heterocysts are properly balanced to ensure optimal growth and keep a competitive edge for long-term survival.

scholarly journals Novel DNA-Binding Proteins in the Cyanobacterium Anabaena sp. Strain PCC 7120

2002 ◽  
Vol 184 (14) ◽  
pp. 3931-3940 ◽  
Author(s):  
Olga A. Koksharova ◽  
C. Peter Wolk
Keyword(s):  
Dna Binding ◽  
Insertional Mutagenesis ◽  
Binding Proteins ◽  
Dna Binding Proteins ◽  
Vegetative Cells ◽  
Heterocyst Differentiation ◽  
The Third ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120

ABSTRACT As an approach towards elucidation of the biochemical regulation of the progression of heterocyst differentiation in Anabaena sp. strain PCC 7120, we have identified proteins that bind to a 150-bp sequence upstream from hepC, a gene that plays a role in the synthesis of heterocyst envelope polysaccharide. Such proteins were purified in four steps from extracts of vegetative cells of Anabaena sp. Two of these proteins (Abp1 and Abp2) are encoded by neighboring genes in the Anabaena sp. chromosome. The genes that encode the third (Abp3) and fourth (Abp4) proteins are situated at two other loci in that chromosome. Insertional mutagenesis of abp2 and abp3 blocked expression of hepC and hepA and prevented heterocyst maturation and aerobic fixation of N2.

scholarly journals Thioredoxin targets are regulated in heterocysts of cyanobacterium Anabaena sp. PCC 7120 in a light-independent manner

2019 ◽  
Vol 71 (6) ◽  
pp. 2018-2027
Author(s):  
Shoko Mihara ◽  
Kazunori Sugiura ◽  
Keisuke Yoshida ◽  
Toru Hisabori
Keyword(s):  
Redox Regulation ◽  
Regulation System ◽  
Regulation Mechanism ◽  
Light Conditions ◽  
Nitrogen Fixing ◽  
Vegetative Cells ◽  
Target Proteins ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120

Abstract In the nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120, glucose 6-phosphate dehydrogenase (G6PDH) plays an important role in producing the power for reducing nitrogenase under light conditions. Our previous study showed that thioredoxin suppresses G6PDH by reducing its activator protein OpcA, implying that G6PDH is inactivated under light conditions because thioredoxins are reduced by the photosynthetic electron transport system in cyanobacteria. To address how Anabaena sp. PCC 7120 maintains G6PDH activity even under light conditions when nitrogen fixation occurs, we investigated the redox regulation system in vegetative cells and specific nitrogen-fixing cells named heterocysts, individually. We found that thioredoxin target proteins were more oxidized in heterocysts than in vegetative cells under light conditions. Alterations in the redox regulation mechanism of heterocysts may affect the redox states of thioredoxin target proteins, including OpcA, so that G6PDH is activated in heterocysts even under light conditions.

Expanding the Natural Products Heterologous Expression Repertoire in the Model Cyanobacterium Anabaena sp. Strain PCC 7120: Production of Pendolmycin and Teleocidin B-4

2019 ◽  
Author(s):  
Patrick Videau ◽  
Kaitlyn Wells ◽  
Arun Singh ◽  
Jessie Eiting ◽  
Philip Proteau ◽  
...  
Keyword(s):  
Natural Products ◽  
Genome Mining ◽  
Gene Clusters ◽  
Combinatorial Biosynthesis ◽  
Test Case ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120

Cyanobacteria are prolific producers of natural products and genome mining has shown that many orphan biosynthetic gene clusters can be found in sequenced cyanobacterial genomes. New tools and methodologies are required to investigate these biosynthetic gene clusters and here we present the use of <i>Anabaena </i>sp. strain PCC 7120 as a host for combinatorial biosynthesis of natural products using the indolactam natural products (lyngbyatoxin A, pendolmycin, and teleocidin B-4) as a test case. We were able to successfully produce all three compounds using codon optimized genes from Actinobacteria. We also introduce a new plasmid backbone based on the native <i>Anabaena</i>7120 plasmid pCC7120ζ and show that production of teleocidin B-4 can be accomplished using a two-plasmid system, which can be introduced by co-conjugation.

Target Gene Inactivation in Cyanobacterium Anabaena sp. PCC 7120

BIO-PROTOCOL ◽  
2016 ◽  
Vol 6 (15) ◽  
Author(s):  
Kangming Chen ◽  
Huilan Zhu ◽  
Liping Gu ◽  
Shengni Tian ◽  
Ruanbao Zhou
Keyword(s):  
Target Gene ◽  
Gene Inactivation ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120

scholarly journals Spatio-Temporal Gene Induction Systems in the Heterocyst-Forming Multicellular Cyanobacterium Anabaena sp. PCC 7120

2017 ◽  
Vol 59 (1) ◽  
pp. 82-89 ◽  
Author(s):  
Akiyoshi Higo ◽  
Atsuko Isu ◽  
Yuki Fukaya ◽  
Toru Hisabori
Keyword(s):  
Gene Induction ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Spatio Temporal ◽  
Pcc 7120

scholarly journals Manipulation of Pattern of Cell Differentiation in a hetR Mutant of Anabaena sp. PCC 7120 by Overexpressing hetZ Alone or with hetP

Life ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 60 ◽  
Author(s):  
He Zhang ◽  
Xudong Xu
Keyword(s):  
Cell Differentiation ◽  
Peptide Inhibitor ◽  
Filamentous Cyanobacterium ◽  
Heterocyst Differentiation ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120

In the filamentous cyanobacterium, Anabaena sp. PCC 7120, single heterocysts differentiate at semi-regular intervals in response to nitrogen stepdown. HetR is a principal regulator of heterocyst differentiation, and hetP and hetZ are two genes that are regulated directly by HetR. In a hetR mutant generated from the IHB (Institute of Hydrobiology) substrain of PCC 7120, heterocyst formation can be restored by moderate expression of hetZ and hetP. The resulting heterocysts are located at terminal positions. We used a tandem promoter, PrbcLPpetE, to express hetZ and hetP strongly in the hetR mutant. Co-expression of hetZ and hetP enabled the hetR mutant to form multiple contiguous heterocysts at both terminal and intercalary positions. Expression of hetZ, alone resulted in terminally located heterocysts, whereas expression of hetP, alone produced enlarged cells in strings. In the absence of HetR, formation of heterocysts was insensitive to the peptide inhibitor, RGSGR.

scholarly journals Inactivation of a Heterocyst-Specific Invertase Indicates a Principal Role of Sucrose Catabolism in Heterocysts of Anabaena sp.

2010 ◽  
Vol 192 (20) ◽  
pp. 5526-5533 ◽  
Author(s):  
Rocío López-Igual ◽  
Enrique Flores ◽  
Antonia Herrero
Keyword(s):  
Fluorescent Protein ◽  
Northern Analysis ◽  
Filamentous Cyanobacterium ◽  
Nitrogen Deprivation ◽  
Vegetative Cells ◽  
Anabaena Sp ◽  
Green Fluorescent ◽  
Pcc 7120 ◽  
Diazotrophic Growth

ABSTRACT Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that carries out N2 fixation in specialized cells called heterocysts, which exchange nutrients and regulators with the filament's vegetative cells that perform the photosynthetic fixation of CO2. The Anabaena genome carries two genes coding for alkaline/neutral invertases, invA and invB. As shown by Northern analysis, both genes were expressed monocistronically and induced under nitrogen deprivation, although induction was stronger for invB than for invA. Whereas expression of an InvA-N-GFP fusion (green fluorescent protein [GFP] fused to the N terminus of the InvA protein [InvA-N]) was homogeneous along the cyanobacterial filament, consistent with the lack of dependence on HetR, expression of an InvB-N-GFP fusion upon combined nitrogen deprivation took place mainly in differentiating and mature heterocysts. In an hetR genetic background, the InvB-N-GFP fusion was strongly expressed all along the filament. An insertional mutant of invA could grow diazotrophically but was impaired in nifHDK induction and exhibited an increased frequency of heterocysts, suggesting a regulatory role of the invertase-mediated carbon flux in vegetative cells. In contrast, an invB mutant was strongly impaired in diazotrophic growth, showing a crucial role of sucrose catabolism mediated by the InvB invertase in the heterocysts.

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