scholarly journals Clustered Genes Required for the Synthesis of Heterocyst Envelope Polysaccharide in Anabaena sp. Strain PCC 7120

2005 ◽  
Vol 187 (3) ◽  
pp. 1114-1123 ◽  
Author(s):  
Guocun Huang ◽  
Qing Fan ◽  
Sigal Lechno-Yossef ◽  
Elizabeth Wojciuch ◽  
C. Peter Wolk ◽  
...  
Keyword(s):  
Open Reading Frames ◽  
Filamentous Cyanobacterium ◽  
Anabaena Sp ◽  
Pcc 7120 ◽  
Polysaccharide Layer ◽  
Reading Frames

ABSTRACT As demonstrated with alr2835 (hepA) and alr2834 (hepC) mutants, heterocysts of Anabaena sp. strain PCC 7120, a filamentous cyanobacterium, must have an envelope polysaccharide layer (the Hep+ phenotype) to fix dinitrogen in an oxygen-containing milieu (the Fox+ phenotype). Transpositions presumptively responsible for a Fox− phenotype were localized in open reading frames (ORFs) near hepA and hepC. A mutation in each of nine of these ORFs was complemented by a clone bearing only that single, intact ORF. Heterocysts of the nine mutants were found to lack an envelope polysaccharide layer. Complementation of mutations in alr2832 and alr2840 may have resulted from recombination. However, alr2825, alr2827, alr2831, alr2833, alr2837, alr2839, and alr2841, like hepA and hepC, are required for a Hep+ Fox+ phenotype.

scholarly journals The Insertion Sequences of Anabaena sp. Strain PCC 7120 and Their Effects on Its Open Reading Frames

2010 ◽  
Vol 192 (20) ◽  
pp. 5289-5303 ◽  
Author(s):  
C. Peter Wolk ◽  
Sigal Lechno-Yossef ◽  
Karin M. Jäger
Keyword(s):  
Transposable Elements ◽  
Open Reading Frames ◽  
Insertion Sequences ◽  
Direct Repeats ◽  
Homologous Sequences ◽  
Anabaena Sp ◽  
Pcc 7120 ◽  
Flanking Regions ◽  
Adaptive Role ◽  
Reading Frames

ABSTRACT Anabaena sp. strain PCC 7120, widely studied, has 145 annotated transposase genes that are part of transposable elements called insertion sequences (ISs). To determine the entirety of the ISs, we aligned transposase genes and their flanking regions; identified the ISs' possible terminal inverted repeats, usually flanked by direct repeats; and compared IS-interrupted sequences with homologous sequences. We thereby determined both ends of 87 ISs bearing 110 transposase genes in eight IS families (http://www-is.biotoul.fr/ ) and in a cluster of unclassified ISs, and of hitherto unknown miniature inverted-repeat transposable elements. Open reading frames were then identified to which ISs contributed and others—some encoding proteins of predictable function, including protein kinases, and restriction endonucleases—that were interrupted by ISs. Anabaena sp. ISs were often more closely related to exogenous than to other endogenous ISs, suggesting that numerous variant ISs were not degraded within PCC 7120 but transferred from without. This observation leads to the expectation that further sequencing projects will extend this and similar analyses. We also propose an adaptive role for poly(A) sequences in ISs.

scholarly journals A TRAP Transporter for Pyruvate and Other Monocarboxylate 2-Oxoacids in the Cyanobacterium Anabaena sp. Strain PCC 7120

2010 ◽  
Vol 192 (22) ◽  
pp. 6089-6092 ◽  
Author(s):  
Rafael Pernil ◽  
Antonia Herrero ◽  
Enrique Flores
Keyword(s):  
Open Reading Frames ◽  
Wild Type ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Significant Uptake ◽  
Pcc 7120 ◽  
Reading Frames ◽  
T System

ABSTRACT In the cyanobacterium Anabaena sp. strain PCC 7120, open reading frames (ORFs) alr3026, alr3027, and all3028 encode a tripartite ATP-independent periplasmic transporter (TRAP-T). Wild-type filaments showed significant uptake of [14C]pyruvate, which was impaired in the alr3027 and all3028 mutants and was inhibited by several monocarboxylate 2-oxoacids, identifying this TRAP-T system as a pyruvate/monocarboxylate 2-oxoacid transporter.

Expression, nucleotide sequence and mutational analysis of two open reading frames in the nif gene region of Anabaena sp. strain PCC 7120

1990 ◽  
Vol 221 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Dulal Borthakur ◽  
Michele Basche ◽  
William J. Buikema ◽  
Pritty B. Borthakur ◽  
Robert Haselkorn
Keyword(s):  
Nucleotide Sequence ◽  
Mutational Analysis ◽  
Open Reading Frames ◽  
Gene Region ◽  
Anabaena Sp ◽  
Nif Gene ◽  
Pcc 7120 ◽  
Reading Frames

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.

scholarly journals Anabaena sp. Strain PCC 7120 hetY Gene Influences Heterocyst Development

2003 ◽  
Vol 185 (23) ◽  
pp. 6995-7000 ◽  
Author(s):  
Ho-Sung Yoon ◽  
Martin H. Lee ◽  
Jin Xiong ◽  
James W. Golden
Keyword(s):  
Atp Binding ◽  
Binding Motif ◽  
Filamentous Cyanobacterium ◽  
Hypothetical Proteins ◽  
Nitrogen Fixing ◽  
Fixed Nitrogen ◽  
Anabaena Sp ◽  
Time Required ◽  
Pcc 7120 ◽  
Heterocyst Development

ABSTRACT The filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 responds to starvation for fixed nitrogen by producing a semiregular pattern of nitrogen-fixing cells called heterocysts. Overexpression of the hetY gene partially suppressed heterocyst formation, resulting in an abnormal heterocyst pattern. Inactivation of hetY increased the time required for heterocyst maturation and caused defects in heterocyst morphology. The 489-bp hetY gene (alr2300), which is adjacent to patS (asl2301), encodes a protein that belongs to a conserved family of bacterial hypothetical proteins that contain an ATP-binding motif.

alr0117, a two-component histidine kinase gene, is involved in heterocyst development in Anabaena sp. PCC 7120

Microbiology ◽  
2004 ◽  
Vol 150 (2) ◽  
pp. 447-453 ◽  
Author(s):  
Degang Ning ◽  
Xudong Xu
Keyword(s):  
Histidine Kinase ◽  
Regulatory System ◽  
Gene Encoding ◽  
Kinase Gene ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
Anabaena Sp ◽  
Pcc 7120 ◽  
Polysaccharide Layer ◽  
Heterocyst Development

Anabaena sp. PCC 7120 was mutagenized by transposon Tn5-1087b, generating a mutant whose heterocysts lack the envelope polysaccharide layer. The transposon was located between nucleotides 342 and 343 of alr0117, a 918 bp gene encoding a histidine kinase for a two-component regulatory system. Complementation of the mutant with a DNA fragment containing alr0117 and targeted inactivation of the gene confirmed that alr0117 is involved in heterocyst development. RT-PCR showed that alr0117 was constitutively expressed in the presence or absence of a combined-nitrogen source. hepA and patB, the two genes turned on during wild-type heterocyst development, were no longer activated in an alr0117-null mutant. The two-component signal transduction system involving alr0117 may control the formation of the envelope polysaccharide layer and certain late events essential to the function of heterocysts.

Early candidacy for differentiation into heterocysts in the filamentous cyanobacterium Anabaena sp. PCC 7120

2009 ◽  
Vol 192 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Masakazu Toyoshima ◽  
Naobumi V. Sasaki ◽  
Makoto Fujiwara ◽  
Shigeki Ehira ◽  
Masayuki Ohmori ◽  
...  
Keyword(s):  
Filamentous Cyanobacterium ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120

An increase in the level of 2-oxoglutarate promotes heterocyst development in the cyanobacterium Anabaena sp. strain PCC 7120

Microbiology ◽  
2003 ◽  
Vol 149 (11) ◽  
pp. 3257-3263 ◽  
Author(s):  
Jian-Hong Li ◽  
Sophie Laurent ◽  
Viren Konde ◽  
Sylvie Bédu ◽  
Cheng-Cai Zhang
Keyword(s):  
Inorganic Nitrogen ◽  
Cell Types ◽  
Filamentous Cyanobacterium ◽  
Nitrogen Status ◽  
Gene Encoding ◽  
Combined Nitrogen ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
Pcc 7120 ◽  
Heterocyst Development

In the filamentous cyanobacterium Anabaena sp. strain PCC 7120, a starvation of combined nitrogen induces differentiation of heterocysts, cells specialized in nitrogen fixation. How do filaments perceive the limitation of the source of combined nitrogen, and what determines the proportion of heterocysts? In cyanobacteria, 2-oxoglutarate provides a carbon skeleton for the incorporation of inorganic nitrogen. Recently, it has been proposed that the concentration of 2-oxoglutarate reflects the nitrogen status in cyanobacteria. To investigate the effect of 2-oxoglutarate on heterocyst development, a heterologous gene encoding a 2-oxoglutarate permease under the control of a regulated promoter was expressed in Anabaena sp. PCC 7120. The increase of 2-oxoglutarate within cells can trigger heterocyst differentiation in a subpopulation of filaments even in the presence of nitrate. In the absence of a source of combined nitrogen, it can increase heterocyst frequency, advance the timing of commitment to heterocyst development and further increase the proportion of heterocysts in a patS mutant. Here, it is proposed that the intracellular concentration of 2-oxoglutarate is involved in the determination of the proportion of the two cell types according to the carbon/nitrogen status of the filament.

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