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Heterocyst Septa Contain Large Nanopores That Are Influenced by the Fra Proteins in the Filamentous Cyanobacterium Anabaena sp. Strain PCC 7120. J Bacteriol 2021; 203:e0008121. [PMID: 33846119 DOI: 10.1128/jb.00081-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Multicellular heterocyst-forming cyanobacteria, such as Anabaena, grow as chains of cells forming filaments that, under diazotrophic conditions, contain two cell types: vegetative cells that perform oxygenic photosynthesis and N2-fixing heterocysts. Along the filament, the intercellular septa contain a thick peptidoglycan layer that forms septal disks. Proteinaceous septal junctions connect the cells in the filament traversing the septal disks through nanopores. The fraCDE operon encodes proteins needed to make long filaments in Anabaena. FraC and FraD, located at the intercellular septa, are involved in the formation of septal junctions. Using a superfolder-green fluorescent protein (GFP) fusion, we found in this study that FraE is mainly localized to the poles of the heterocysts, consistent with the requirement of FraE for constriction of the heterocyst poles to form the "heterocyst neck." A fraE insertional mutant was impaired by 22% to 38% in transfer of fluorescent calcein from vegetative cells to heterocysts. Septal disks were inspected in murein sacculi from heterocyst-enriched preparations. Unexpectedly, the diameter of the nanopores in heterocyst septa was about 1.5- to 2-fold larger than in vegetative cell septa. The number of these nanopores was 76% and 6% of the wild-type number in fraE and fraC fraD mutants, respectively. Our results show that FraE is mainly involved in heterocyst maturation, whereas FraC and FraD are needed for the formation of the large nanopores of heterocyst septa, as they are for vegetative cell nanopores. Additionally, arrays of small pores conceivably involved in polysaccharide export were observed close to the septal disks in the heterocyst murein sacculus preparations. IMPORTANCE Intercellular communication, an essential attribute of multicellularity, is required for diazotrophic growth in heterocyst-forming cyanobacteria such as Anabaena, in which the cells are connected by proteinaceous septal junctions that are structural analogs of metazoan connexons. The septal junctions allow molecular intercellular diffusion traversing the septal peptidoglycan through nanopores. In Anabaena the fraCDE operon encodes septal proteins involved in intercellular communication. FraC and FraD are components of the septal junctions along the filament, whereas here we show that FraE is mainly present at the heterocyst poles. We found that the intercellular septa in murein sacculi from heterocysts contain nanopores that are larger than those in vegetative cells, establishing a previously unknown difference between heterocyst and vegetative cell septa in Anabaena.
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Camargo S, Leshkowitz D, Dassa B, Mariscal V, Flores E, Stavans J, Arbel-Goren R. Impaired cell-cell communication in the multicellular cyanobacterium Anabaena affects carbon uptake, photosynthesis, and the cell wall. iScience 2021; 24:101977. [PMID: 33458622 PMCID: PMC7797909 DOI: 10.1016/j.isci.2020.101977] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/08/2020] [Accepted: 12/17/2020] [Indexed: 12/23/2022] Open
Abstract
Cell-cell communication is an essential attribute of multicellular organisms. The effects of perturbed communication were studied in septal protein mutants of the heterocyst-forming filamentous cyanobacterium Anabaena sp. PCC 7120 model organism. Strains bearing sepJ and sepJ/fraC/fraD deletions showed differences in growth, pigment absorption spectra, and spatial patterns of expression of the hetR gene encoding a heterocyst differentiation master regulator. Global changes in gene expression resulting from deletion of those genes were mapped by RNA sequencing analysis of wild-type and mutant strains, both under nitrogen-replete and nitrogen-poor conditions. The effects of sepJ and fraC/fraD deletions were non-additive, and perturbed cell-cell communication led to significant changes in global gene expression. Most significant effects, related to carbon metabolism, included increased expression of genes encoding carbon uptake systems and components of the photosynthetic apparatus, as well as decreased expression of genes encoding cell wall components related to heterocyst differentiation and to polysaccharide export.
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Affiliation(s)
- Sergio Camargo
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dena Leshkowitz
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Bareket Dassa
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Joel Stavans
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Rinat Arbel-Goren
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
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3
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LytR-CpsA-Psr Glycopolymer Transferases: Essential Bricks in Gram-Positive Bacterial Cell Wall Assembly. Int J Mol Sci 2021; 22:ijms22020908. [PMID: 33477538 PMCID: PMC7831098 DOI: 10.3390/ijms22020908] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/14/2021] [Accepted: 01/14/2021] [Indexed: 12/28/2022] Open
Abstract
The cell walls of Gram-positive bacteria contain a variety of glycopolymers (CWGPs), a significant proportion of which are covalently linked to the peptidoglycan (PGN) scaffolding structure. Prominent CWGPs include wall teichoic acids of Staphylococcus aureus, streptococcal capsules, mycobacterial arabinogalactan, and rhamnose-containing polysaccharides of lactic acid bacteria. CWGPs serve important roles in bacterial cellular functions, morphology, and virulence. Despite evident differences in composition, structure and underlaying biosynthesis pathways, the final ligation step of CWGPs to the PGN backbone involves a conserved class of enzymes-the LytR-CpsA-Psr (LCP) transferases. Typically, the enzymes are present in multiple copies displaying partly functional redundancy and/or preference for a distinct CWGP type. LCP enzymes require a lipid-phosphate-linked glycan precursor substrate and catalyse, with a certain degree of promiscuity, CWGP transfer to PGN of different maturation stages, according to in vitro evidence. The prototype attachment mode is that to the C6-OH of N-acetylmuramic acid residues via installation of a phosphodiester bond. In some cases, attachment proceeds to N-acetylglucosamine residues of PGN-in the case of the Streptococcus agalactiae capsule, even without involvement of a phosphate bond. A novel aspect of LCP enzymes concerns a predicted role in protein glycosylation in Actinomyces oris. Available crystal structures provide further insight into the catalytic mechanism of this biologically important class of enzymes, which are gaining attention as new targets for antibacterial drug discovery to counteract the emergence of multidrug resistant bacteria.
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Kurio Y, Koike Y, Kanesaki Y, Watanabe S, Ehira S. The CRP-family transcriptional regulator DevH regulates expression of heterocyst-specific genes at the later stage of differentiation in the cyanobacterium Anabaena sp. strain PCC 7120. Mol Microbiol 2020; 114:553-562. [PMID: 32564445 DOI: 10.1111/mmi.14558] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/20/2020] [Accepted: 05/22/2020] [Indexed: 12/16/2022]
Abstract
Heterocysts are terminally differentiated cells of filamentous cyanobacteria, which are specialized for nitrogen fixation. Because nitrogenase is easily inactivated by oxygen, the intracellular environment of heterocysts is kept microoxic. In heterocysts, the oxygen-evolving photosystem II is inactivated, a heterocyst-specific envelope with an outer polysaccharide layer and an inner glycolipid layer is formed to limit oxygen entry, and oxygen consumption is activated. Heterocyst differentiation, which is accompanied by drastic morphological and physiological changes, requires strictly controlled gene expression systems. Here, we investigated the functions of a CRP-family transcriptional regulator, DevH, in the process of heterocyst differentiation. A devH-knockdown strain, devH-kd, was created by replacing the original promoter with the gifA promoter, which is repressed during heterocyst differentiation. Although devH-kd formed morphologically distinct cells with the heterocyst envelope polysaccharide layer, it was unable to grow diazotrophically. Genes involved in construction of the microoxic environment, such as cox operons and the hgl island, were not upregulated in devH-kd. Moreover, expression of the nif gene cluster was completely abolished. Although CnfR was expressed in devH-kd, the nif gene cluster was not induced even under microoxic conditions. Thus, DevH is necessary for the establishment of a microoxic environment and induction of nitrogenase in heterocysts.
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Affiliation(s)
- Yohei Kurio
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo, Japan
| | - Yosuke Koike
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo, Japan
| | - Yu Kanesaki
- NODAI Genome Research Center, Tokyo University of Agriculture, Tokyo, Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Shigeki Ehira
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo, Japan
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Cellular Innovation of the Cyanobacterial Heterocyst by the Adaptive Loss of Plasticity. Curr Biol 2020; 30:344-350.e4. [PMID: 31928871 DOI: 10.1016/j.cub.2019.11.056] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/12/2019] [Accepted: 11/18/2019] [Indexed: 10/25/2022]
Abstract
Cellular innovation is central to biological diversification, yet its underlying mechanisms remain poorly understood [1]. One potential source of new cellular traits is environmentally induced phenotypic variation, or phenotypic plasticity. The plasticity-first hypothesis [2-4] proposes that natural selection can improve upon an ancestrally plastic phenotype to produce a locally adaptive trait, but the role of plasticity for adaptive evolution is still unclear [5-10]. Here, we show that a structurally novel form of the heterocyst, the specialized nitrogen-fixing cell of the multicellular cyanobacterium Fischerella thermalis, has evolved multiple times from ancestrally plastic developmental variation during adaptation to high temperature. Heterocyst glycolipids (HGs) provide an extracellular gas diffusion barrier that protects oxygen-sensitive nitrogenase [11, 12], and cyanobacteria typically exhibit temperature-induced plasticity in HG composition that modulates heterocyst permeability [13, 14]. By contrast, high-temperature specialists of F. thermalis constitutively overproduce glycolipid isomers associated with high temperature to levels unattained by plastic strains. This results in a less-permeable heterocyst, which is advantageous at high temperature but deleterious at low temperature for both nitrogen fixation activity and fitness. Our study illustrates how the origin of a novel cellular phenotype by the genetic assimilation and adaptive refinement of a plastic trait can be a source of biological diversity and contribute to ecological specialization.
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Pankievicz VCS, Irving TB, Maia LGS, Ané JM. Are we there yet? The long walk towards the development of efficient symbiotic associations between nitrogen-fixing bacteria and non-leguminous crops. BMC Biol 2019; 17:99. [PMID: 31796086 PMCID: PMC6889567 DOI: 10.1186/s12915-019-0710-0] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 10/18/2019] [Indexed: 01/09/2023] Open
Abstract
Nitrogen is an essential element of life, and nitrogen availability often limits crop yields. Since the Green Revolution, massive amounts of synthetic nitrogen fertilizers have been produced from atmospheric nitrogen and natural gas, threatening the sustainability of global food production and degrading the environment. There is a need for alternative means of bringing nitrogen to crops, and taking greater advantage of biological nitrogen fixation seems a logical option. Legumes are used in most cropping systems around the world because of the nitrogen-fixing symbiosis with rhizobia. However, the world's three major cereal crops-rice, wheat, and maize-do not associate with rhizobia. In this review, we will survey how genetic approaches in rhizobia and their legume hosts allowed tremendous progress in understanding the molecular mechanisms controlling root nodule symbioses, and how this knowledge paves the way for engineering such associations in non-legume crops. We will also discuss challenges in bringing these systems into the field and how they can be surmounted by interdisciplinary collaborations between synthetic biologists, microbiologists, plant biologists, breeders, agronomists, and policymakers.
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Affiliation(s)
| | - Thomas B Irving
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Lucas G S Maia
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Jean-Michel Ané
- Department of Agronomy, University of Wisconsin, Madison, WI, USA.
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA.
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Shvarev D, Maldener I. ATP-binding cassette transporters of the multicellular cyanobacterium Anabaena sp. PCC 7120: a wide variety for a complex lifestyle. FEMS Microbiol Lett 2019; 365:4817535. [PMID: 29360977 DOI: 10.1093/femsle/fny012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/18/2018] [Indexed: 01/29/2023] Open
Abstract
Two hundred genes or 3% of the known or putative protein-coding genes of the filamentous freshwater cyanobacterium Anabaena sp. PCC 7120 encode domains of ATP-binding cassette (ABC) transporters. Detailed characterization of some of these transporters (14-15 importers and 5 exporters) has revealed their crucial roles in the complex lifestyle of this multicellular photoautotroph, which is able to differentiate specialized cells for nitrogen fixation. This review summarizes the characteristics of the ABC transporters of Anabaena sp. PCC 7120 known to date.
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Affiliation(s)
- Dmitry Shvarev
- Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
| | - Iris Maldener
- Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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8
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Kourpa K, Manarolaki E, Lyratzakis A, Strataki V, Rupprecht F, Langer JD, Tsiotis G. Proteome Analysis of Enriched Heterocysts from Two Hydrogenase Mutants fromAnabaenasp. PCC 7120. Proteomics 2019; 19:e1800332. [DOI: 10.1002/pmic.201800332] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 07/12/2019] [Indexed: 11/08/2022]
Affiliation(s)
- Katerina Kourpa
- Division of BiochemistryDepartment of ChemistryUniversity of Crete P.O. Box 2208, GR‐71003 Voutes Greece
| | - Eftychia Manarolaki
- Division of BiochemistryDepartment of ChemistryUniversity of Crete P.O. Box 2208, GR‐71003 Voutes Greece
| | - Alexandros Lyratzakis
- Division of BiochemistryDepartment of ChemistryUniversity of Crete P.O. Box 2208, GR‐71003 Voutes Greece
| | - Vasso Strataki
- Division of BiochemistryDepartment of ChemistryUniversity of Crete P.O. Box 2208, GR‐71003 Voutes Greece
| | - Fiona Rupprecht
- Max Planck Institute for Brain Research Max‐von‐Laue‐Straße 4 D‐60438 Frankfurt am Main Germany
| | - Julian D. Langer
- Max Planck Institute for Brain Research Max‐von‐Laue‐Straße 4 D‐60438 Frankfurt am Main Germany
- Max Planck Institute for Biophysics Max‐von‐Laue‐Straße 3 D‐60438 Frankfurt am Main Germany
| | - Georgios Tsiotis
- Division of BiochemistryDepartment of ChemistryUniversity of Crete P.O. Box 2208, GR‐71003 Voutes Greece
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9
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Flores E, Picossi S, Valladares A, Herrero A. Transcriptional regulation of development in heterocyst-forming cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:673-684. [DOI: 10.1016/j.bbagrm.2018.04.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 01/02/2023]
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10
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Brenes‐Álvarez M, Mitschke J, Olmedo‐Verd E, Georg J, Hess WR, Vioque A, Muro‐Pastor AM. Elements of the heterocyst‐specific transcriptome unravelled by co‐expression analysis inNostocsp. PCC 7120. Environ Microbiol 2019; 21:2544-2558. [DOI: 10.1111/1462-2920.14647] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/06/2019] [Accepted: 05/01/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Manuel Brenes‐Álvarez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla E‐41092 Sevilla Spain
| | - Jan Mitschke
- Genetics and Experimental Bioinformatics, Faculty of BiologyUniversity of Freiburg D‐79104 Freiburg Germany
| | - Elvira Olmedo‐Verd
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla E‐41092 Sevilla Spain
| | - Jens Georg
- Genetics and Experimental Bioinformatics, Faculty of BiologyUniversity of Freiburg D‐79104 Freiburg Germany
| | - Wolfgang R. Hess
- Genetics and Experimental Bioinformatics, Faculty of BiologyUniversity of Freiburg D‐79104 Freiburg Germany
- Freiburg Institute for Advanced Studies, University of Freiburg D‐79104 Freiburg Germany
| | - Agustín Vioque
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla E‐41092 Sevilla Spain
| | - Alicia M. Muro‐Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla E‐41092 Sevilla Spain
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11
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Brouwer E, Ngo G, Yadav S, Ladig R, Schleiff E. Tic22 from
Anabaena
sp. PCC 7120 with holdase function involved in outer membrane protein biogenesis shuttles between plasma membrane and Omp85. Mol Microbiol 2019; 111:1302-1316. [DOI: 10.1111/mmi.14222] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/07/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Eva‐Maria Brouwer
- Institute for Molecular Biosciences Goethe University Frankfurt am Main Frankfurt am Main Germany
| | - Giang Ngo
- Institute for Molecular Biosciences Goethe University Frankfurt am Main Frankfurt am Main Germany
| | - Shivam Yadav
- Institute for Molecular Biosciences Goethe University Frankfurt am Main Frankfurt am Main Germany
- Centre of Advanced Studies in Botany, Institute of Science Banaras Hindu University Varanasi India
| | - Roman Ladig
- Institute for Molecular Biosciences Goethe University Frankfurt am Main Frankfurt am Main Germany
| | - Enrico Schleiff
- Institute for Molecular Biosciences Goethe University Frankfurt am Main Frankfurt am Main Germany
- Buchman Institute for Molecular Life Sciences Goethe University Frankfurt am Main Frankfurt am Main Germany
- Frankfurt Institute of Advanced Studies Frankfurt am Main Germany
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12
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Shvarev D, Nishi CN, Maldener I. Glycolipid composition of the heterocyst envelope of Anabaena sp. PCC 7120 is crucial for diazotrophic growth and relies on the UDP-galactose 4-epimerase HgdA. Microbiologyopen 2019; 8:e00811. [PMID: 30803160 PMCID: PMC6692557 DOI: 10.1002/mbo3.811] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/10/2019] [Accepted: 01/14/2019] [Indexed: 01/05/2023] Open
Abstract
The nitrogenase complex in the heterocysts of the filamentous freshwater cyanobacterium Anabaenasp. PCC 7120 fixes atmospheric nitrogen to allow diazotrophic growth. The heterocyst cell envelope protects the nitrogenase from oxygen and consists of a polysaccharide and a glycolipid layer that are formed by a complex process involving the recruitment of different proteins. Here, we studied the function of the putative nucleoside‐diphosphate‐sugar epimerase HgdA, which along with HgdB and HgdC is essential for deposition of the glycolipid layer and growth without a combined nitrogen source. Using site‐directed mutagenesis and single homologous recombination approach, we performed a thoroughly functional characterization of HgdA and confirmed that the glycolipid layer of the hgdAmutant heterocyst is aberrant as shown by transmission electron microscopy and chemical analysis. The hgdA gene was expressed during late stages of the heterocyst differentiation. GFP‐tagged HgdA protein localized inside the heterocysts. The purified HgdA protein had UDP‐galactose 4‐epimerase activity in vitro. This enzyme could be responsible for synthesis of heterocyst‐specific glycolipid precursors, which could be transported over the cell wall by the ABC transporter components HgdB/HgdC.
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Affiliation(s)
- Dmitry Shvarev
- Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Carolina N Nishi
- Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Iris Maldener
- Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Tübingen, Germany
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13
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Herrero A, Flores E. Genetic responses to carbon and nitrogen availability in Anabaena. Environ Microbiol 2018; 21:1-17. [PMID: 30066380 DOI: 10.1111/1462-2920.14370] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/27/2018] [Accepted: 07/29/2018] [Indexed: 11/27/2022]
Abstract
Heterocyst-forming cyanobacteria are filamentous organisms that perform oxygenic photosynthesis and CO2 fixation in vegetative cells and nitrogen fixation in heterocysts, which are formed under deprivation of combined nitrogen. These organisms can acclimate to use different sources of nitrogen and respond to different levels of CO2 . Following work mainly done with the best studied heterocyst-forming cyanobacterium, Anabaena, here we summarize the mechanisms of assimilation of ammonium, nitrate, urea and N2 , the latter involving heterocyst differentiation, and describe aspects of CO2 assimilation that involves a carbon concentration mechanism. These processes are subjected to regulation establishing a hierarchy in the assimilation of nitrogen sources -with preference for the most reduced nitrogen forms- and a dependence on sufficient carbon. This regulation largely takes place at the level of gene expression and is exerted by a variety of transcription factors, including global and pathway-specific transcriptional regulators. NtcA is a CRP-family protein that adjusts global gene expression in response to the C-to-N balance in the cells, and PacR is a LysR-family transcriptional regulator (LTTR) that extensively acclimates the cells to oxygenic phototrophy. A cyanobacterial-specific transcription factor, HetR, is involved in heterocyst differentiation, and other LTTR factors are specifically involved in nitrate and CO2 assimilation.
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Affiliation(s)
- Antonia Herrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Américo Vespucio 49, E-41092, Seville, Spain
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Américo Vespucio 49, E-41092, Seville, Spain
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14
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Qiu Y, Tian S, Gu L, Hildreth M, Zhou R. Identification of surface polysaccharides in akinetes, heterocysts and vegetative cells of Anabaena cylindrica using fluorescein-labeled lectins. Arch Microbiol 2018; 201:17-25. [PMID: 30173343 DOI: 10.1007/s00203-018-1565-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/10/2018] [Accepted: 08/22/2018] [Indexed: 11/26/2022]
Abstract
In response to environmental changes, Anabaena cylindrica differentiate three cell types: vegetative cells for photosynthesis, heterocysts for nitrogen fixation, and akinetes for stress survival. Cell-surface polysaccharides play important roles in cyanobacterial ecophysiology. In this study, specific cell-surface sugars were discovered in heterocysts, akinetes and vegetative cells of A. cylindrica using 20 fluorescein-labeled lectins. Both N-acetylglucosamine-binding lectins WGA and succinylated WGA bound specifically to the vegetative cells. Akinetes bound to three mannose-binding lectins (LCA, PSA, and ConA), and one of the galactose-binding lectins (GSL-I). Heterocyst also bound to ConA. However, the heterocysts in all4388 mutant of Anabaena sp. PCC 7120, in which the putative polysaccharide export protein gene all4388 was disrupted, exhibited diminished binding to ConA. Identification of distinct cell-surface sugar helped us to understand the role of polysaccharide for each cell type. Fluorescence-activated cell sorting may be applicable in isolating each cell type for comparative "omics" studies among the three cell types.
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Affiliation(s)
- Yeyan Qiu
- Department of Biology and Microbiology, South Dakota State University, Brookings, USA
| | - Shengni Tian
- College of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Liping Gu
- Department of Biology and Microbiology, South Dakota State University, Brookings, USA
| | - Michael Hildreth
- Department of Biology and Microbiology, South Dakota State University, Brookings, USA
| | - Ruanbao Zhou
- Department of Biology and Microbiology, South Dakota State University, Brookings, USA.
- BioSNTR, South Dakota State University, Brookings, SD, USA.
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15
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The ABC Transporter Components HgdB and HgdC are Important for Glycolipid Layer Composition and Function of Heterocysts in Anabaena sp. PCC 7120. Life (Basel) 2018; 8:life8030026. [PMID: 30004454 PMCID: PMC6161253 DOI: 10.3390/life8030026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 06/21/2018] [Accepted: 06/28/2018] [Indexed: 12/13/2022] Open
Abstract
Anabaena sp. PCC 7120 is a filamentous cyanobacterium able to fix atmospheric nitrogen in semi-regularly spaced heterocysts. For correct heterocyst function, a special cell envelope consisting of a glycolipid layer and a polysaccharide layer is essential. We investigated the role of the genes hgdB and hgdC, encoding domains of a putative ABC transporter, in heterocyst maturation. We investigated the subcellular localization of the fusion protein HgdC-GFP and followed the differential expression of the hgdB and hgdC genes during heterocyst maturation. Using a single recombination approach, we created a mutant in hgdB gene and studied its phenotype by microscopy and analytical chromatography. Although heterocysts are formed in the mutant, the structure of the glycolipid layer is aberrant and also contains an atypical ratio of the two major glycolipids. As shown by a pull-down assay, HgdB interacts with the outer membrane protein TolC, which indicates a function as a type 1 secretion system. We show that the hgdB-hgdC genes are essential for the creation of micro-oxic conditions by influencing the correct composition of the glycolipid layer for heterocyst function. Our observations confirm the significance of the hgdB-hgdC gene cluster and shed light on a novel mode of regulation of heterocyst envelope formation.
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16
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Driscoll CB, Meyer KA, Šulčius S, Brown NM, Dick GJ, Cao H, Gasiūnas G, Timinskas A, Yin Y, Landry ZC, Otten TG, Davis TW, Watson SB, Dreher TW. A closely-related clade of globally distributed bloom-forming cyanobacteria within the Nostocales. HARMFUL ALGAE 2018; 77:93-107. [PMID: 30005805 DOI: 10.1016/j.hal.2018.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/18/2018] [Accepted: 05/24/2018] [Indexed: 06/08/2023]
Abstract
In order to better understand the relationships among current Nostocales cyanobacterial blooms, eight genomes were sequenced from cultured isolates or from environmental metagenomes of recent planktonic Nostocales blooms. Phylogenomic analysis of publicly available sequences placed the new genomes among a group of 15 genomes from four continents in a distinct ADA clade (Anabaena/Dolichospermum/Aphanizomenon) within the Nostocales. This clade contains four species-level groups, two of which include members with both Anabaena-like and Aphanizomenon flos-aquae-like morphology. The genomes contain many repetitive genetic elements and a sizable pangenome, in which ABC-type transporters are highly represented. Alongside common core genes for photosynthesis, the differentiation of N2-fixing heterocysts, and the uptake and incorporation of the major nutrients P, N and S, we identified several gene pathways in the pangenome that may contribute to niche partitioning. Genes for problematic secondary metabolites-cyanotoxins and taste-and-odor compounds-were sporadically present, as were other polyketide synthase (PKS) and nonribosomal peptide synthetase (NRPS) gene clusters. By contrast, genes predicted to encode the ribosomally generated bacteriocin peptides were found in all genomes.
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Affiliation(s)
- Connor B Driscoll
- Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, OR, 97331, USA
| | - Kevin A Meyer
- Department of Earth & Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005, USA; Cooperative Institute for Great Lakes Research (CIGLR), University of Michigan, Ann Arbor, MI 48109-1005, USA
| | - Sigitas Šulčius
- Laboratory of Algology and Microbial Ecology, Akademijos Str. 2, LT-08412, Vilnius, Lithuania
| | - Nathan M Brown
- Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, OR, 97331, USA
| | - Gregory J Dick
- Department of Earth & Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005, USA
| | - Huansheng Cao
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, 427 E Tyler Mall, Tempe, AZ 85287, USA
| | - Giedrius Gasiūnas
- Department of Protein-DNA Interactions, Institute of Biotechnology, Vilnius University, Saulėtekio av. 7, LT-10257, Vilnius, Lithuania
| | - Albertas Timinskas
- Department of Bioinformatics, Institute of Biotechnology, Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania
| | - Yanbin Yin
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL, USA
| | - Zachary C Landry
- Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, OR, 97331, USA
| | - Timothy G Otten
- Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, OR, 97331, USA
| | - Timothy W Davis
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43402, USA
| | - Susan B Watson
- Environment and Climate Change Canada, Canada Centre for Inland Waters, Burlington, ON L7S 1A1, Canada
| | - Theo W Dreher
- Department of Microbiology, Oregon State University, 226 Nash Hall, Corvallis, OR, 97331, USA; Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, USA.
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17
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Ancient balancing selection on heterocyst function in a cosmopolitan cyanobacterium. Nat Ecol Evol 2018; 2:510-519. [DOI: 10.1038/s41559-017-0435-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 11/29/2017] [Indexed: 11/08/2022]
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18
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Ramos-León F, Mariscal V, Battchikova N, Aro EM, Flores E. Septal protein SepJ from the heterocyst-forming cyanobacterium Anabaena forms multimers and interacts with peptidoglycan. FEBS Open Bio 2017; 7:1515-1526. [PMID: 28979840 PMCID: PMC5623728 DOI: 10.1002/2211-5463.12280] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/20/2017] [Accepted: 07/31/2017] [Indexed: 12/30/2022] Open
Abstract
Heterocyst‐forming cyanobacteria grow as filaments that can be hundreds of cells long. Proteinaceous septal junctions provide cell–cell binding and communication functions in the filament. In Anabaena sp. strain PCC 7120, the SepJ protein is important for the formation of septal junctions. SepJ consists of integral membrane and extramembrane sections – the latter including linker and coiled‐coil domains. SepJ (predicted MW, 81.3 kDa) solubilized from Anabaena membranes was found in complexes of about 296–334 kDa, suggesting that SepJ forms multimeric complexes. We constructed an Anabaena strain producing a double‐tagged SepJ protein (SepJ‐GFP‐His10) and isolated the tagged protein by a two‐step affinity chromatography procedure. Analysis of the purified protein preparation provided no indication of the presence of specific SepJ partners, but suggested that SepJ is processed to remove an N‐terminal fragment. Additionally, pull‐down experiments showed that His6‐tagged versions of SepJ and of the SepJ coiled‐coil domain interact with Anabaena peptidoglycan (PG). Our results indicate that SepJ forms multimers, that it interacts with PG, and that the coiled‐coil domain is involved in this interaction. These observations support the idea that SepJ is a component of the septal junctions that join the cells in the Anabaena filament.
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Affiliation(s)
- Félix Ramos-León
- Instituto de Bioquímica Vegetal y Fotosíntesis CSIC Universidad de Sevilla Spain
| | - Vicente Mariscal
- Instituto de Bioquímica Vegetal y Fotosíntesis CSIC Universidad de Sevilla Spain
| | - Natalia Battchikova
- Laboratory of Molecular Plant Biology Department of Biochemistry University of Turku Finland
| | - Eva-Mari Aro
- Laboratory of Molecular Plant Biology Department of Biochemistry University of Turku Finland
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis CSIC Universidad de Sevilla Spain
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19
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Kudoh K, Kubota G, Fujii R, Kawano Y, Ihara M. Exploration of the 1-deoxy-d-xylulose 5-phosphate synthases suitable for the creation of a robust isoprenoid biosynthesis system. J Biosci Bioeng 2017; 123:300-307. [DOI: 10.1016/j.jbiosc.2016.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 10/04/2016] [Accepted: 10/06/2016] [Indexed: 01/29/2023]
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20
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Johnson TJ, Gibbons JL, Gu L, Zhou R, Gibbons WR. Molecular genetic improvements of cyanobacteria to enhance the industrial potential of the microbe: A review. Biotechnol Prog 2016; 32:1357-1371. [DOI: 10.1002/btpr.2358] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 08/30/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Tylor J. Johnson
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
- Dept. of MicrobiologyThe University of TennesseeKnoxville TN37996
| | - Jaimie L. Gibbons
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
| | - Liping Gu
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
| | - Ruanbao Zhou
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
| | - William R. Gibbons
- Dept. of Biology and MicrobiologySouth Dakota State UniversityBrookings SD57007
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21
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Wang XP, Jiang YL, Dai YN, Cheng W, Chen Y, Zhou CZ. Structural and enzymatic analyses of a glucosyltransferase Alr3699/HepE involved in Anabaena heterocyst envelop polysaccharide biosynthesis. Glycobiology 2015; 26:520-31. [PMID: 26692049 DOI: 10.1093/glycob/cwv167] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 12/13/2015] [Indexed: 01/18/2023] Open
Abstract
Formation of the heterocyst envelope polysaccharide (HEP) is a key process for cyanobacterial heterocyst differentiation. The maturation of HEP in Anabaena sp. strain PCC 7120 is controlled by a gene cluster termed HEP island in addition to an operon alr3698-alr3699, which encodes two putative proteins termed Alr3698/HepD and Alr3699/HepE. Here we report the crystal structures of HepE in the apo-form and three complex forms that bind to UDP-glucose (UDPG), UDP&glucose, and UDP, respectively. The overall structure of HepE displays a typical GT-B fold of glycosyltransferases, comprising two separate β/α/β Rossmann-fold domains that form an inter-domain substrate-binding crevice. Structural analyses combined with enzymatic assays indicate that HepE is a glucosyltransferase using UDPG as a sugar donor. Further site-directed mutageneses enable us to assign the key residues that stabilize the sugar donor and putative acceptor. Based on the comparative structural analyses, we propose a putative catalytic cycle of HepE, which undergoes "open-closed-open" conformational changes upon binding to the substrates and release of products. These findings provide structural and catalytic insights into the first enzyme involved in the HEP biosynthesis pathway.
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Affiliation(s)
- Xue-Ping Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Yong-Liang Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Ya-Nan Dai
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Wang Cheng
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Yuxing Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Cong-Zhao Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
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22
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Simm S, Keller M, Selymesi M, Schleiff E. The composition of the global and feature specific cyanobacterial core-genomes. Front Microbiol 2015; 6:219. [PMID: 25852675 PMCID: PMC4365693 DOI: 10.3389/fmicb.2015.00219] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/04/2015] [Indexed: 12/21/2022] Open
Abstract
Cyanobacteria are photosynthetic prokaryotes important for many ecosystems with a high potential for biotechnological usage e.g., in the production of bioactive molecules. Either asks for a deep understanding of the functionality of cyanobacteria and their interaction with the environment. This in part can be inferred from the analysis of their genomes or proteomes. Today, many cyanobacterial genomes have been sequenced and annotated. This information can be used to identify biological pathways present in all cyanobacteria as proteins involved in such processes are encoded by a so called core-genome. However, beside identification of fundamental processes, genes specific for certain cyanobacterial features can be identified by a holistic genome analysis as well. We identified 559 genes that define the core-genome of 58 analyzed cyanobacteria, as well as three genes likely to be signature genes for thermophilic and 57 genes likely to be signature genes for heterocyst-forming cyanobacteria. To get insights into cyanobacterial systems for the interaction with the environment we also inspected the diversity of the outer membrane proteome with focus on β-barrel proteins. We observed that most of the transporting outer membrane β-barrel proteins are not globally conserved in the cyanobacterial phylum. In turn, the occurrence of β-barrel proteins shows high strain specificity. The core set of outer membrane proteins globally conserved in cyanobacteria comprises three proteins only, namely the outer membrane β-barrel assembly protein Omp85, the lipid A transfer protein LptD, and an OprB-type porin. Thus, we conclude that cyanobacteria have developed individual strategies for the interaction with the environment, while other intracellular processes like the regulation of the protein homeostasis are globally conserved.
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Affiliation(s)
- Stefan Simm
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University Frankfurt am Main, Germany
| | - Mario Keller
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University Frankfurt am Main, Germany
| | - Mario Selymesi
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University Frankfurt am Main, Germany
| | - Enrico Schleiff
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University Frankfurt am Main, Germany ; Cluster of Excellence Frankfurt, Goethe University Frankfurt am Main, Germany ; Center of Membrane Proteomics, Goethe University Frankfurt am Main, Germany ; Buchmann Institute of Molecular Life Sciences, Goethe University Frankfurt am Main, Germany
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23
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Sandh G, Ramström M, Stensjö K. Analysis of the early heterocyst Cys-proteome in the multicellular cyanobacterium Nostoc punctiforme reveals novel insights into the division of labor within diazotrophic filaments. BMC Genomics 2014; 15:1064. [PMID: 25476978 PMCID: PMC4363197 DOI: 10.1186/1471-2164-15-1064] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 11/12/2014] [Indexed: 01/30/2023] Open
Abstract
Background In the filamentous cyanobacterium Nostoc punctiforme ATCC 29133, removal of combined nitrogen induces the differentiation of heterocysts, a cell-type specialized in N2 fixation. The differentiation involves genomic, structural and metabolic adaptations. In cyanobacteria, changes in the availability of carbon and nitrogen have also been linked to redox regulated posttranslational modifications of protein bound thiol groups. We have here employed a thiol targeting strategy to relatively quantify the putative redox proteome in heterocysts as compared to N2-fixing filaments, 24 hours after combined nitrogen depletion. The aim of the study was to expand the coverage of the cell-type specific proteome and metabolic landscape of heterocysts. Results Here we report the first cell-type specific proteome of newly formed heterocysts, compared to N2-fixing filaments, using the cysteine-specific selective ICAT methodology. The data set defined a good quantitative accuracy of the ICAT reagent in complex protein samples. The relative abundance levels of 511 proteins were determined and 74% showed a cell-type specific differential abundance. The majority of the identified proteins have not previously been quantified at the cell-type specific level. We have in addition analyzed the cell-type specific differential abundance of a large section of proteins quantified in both newly formed and steady-state diazotrophic cultures in N. punctiforme. The results describe a wide distribution of members of the putative redox regulated Cys-proteome in the central metabolism of both vegetative cells and heterocysts of N. punctiforme. Conclusions The data set broadens our understanding of heterocysts and describes novel proteins involved in heterocyst physiology, including signaling and regulatory proteins as well as a large number of proteins with unknown function. Significant differences in cell-type specific abundance levels were present in the cell-type specific proteomes of newly formed diazotrophic filaments as compared to steady-state cultures. Therefore we conclude that by using our approach we are able to analyze a synchronized fraction of newly formed heterocysts, which enabled a better detection of proteins involved in the heterocyst specific physiology. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-1064) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | - Karin Stensjö
- Microbial Chemistry, Department of Chemistry - Ångström Laboratory, Science for Life Laboratory, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden.
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24
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Oliveira P, Pinto F, Pacheco CC, Mota R, Tamagnini P. HesF
, an exoprotein required for filament adhesion and aggregation in
A
nabaena
sp.
PCC
7120. Environ Microbiol 2014; 17:1631-48. [DOI: 10.1111/1462-2920.12600] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 08/14/2014] [Indexed: 12/20/2022]
Affiliation(s)
- Paulo Oliveira
- IBMC – Institute for Molecular and Cell Biology University of Porto R. do Campo Alegre, 823 4150‐180 Porto Portugal
| | - Filipe Pinto
- IBMC – Institute for Molecular and Cell Biology University of Porto R. do Campo Alegre, 823 4150‐180 Porto Portugal
| | - Catarina C. Pacheco
- IBMC – Institute for Molecular and Cell Biology University of Porto R. do Campo Alegre, 823 4150‐180 Porto Portugal
| | - Rita Mota
- IBMC – Institute for Molecular and Cell Biology University of Porto R. do Campo Alegre, 823 4150‐180 Porto Portugal
- Department of Biology Faculty of Sciences University of Porto Porto Portugal
| | - Paula Tamagnini
- IBMC – Institute for Molecular and Cell Biology University of Porto R. do Campo Alegre, 823 4150‐180 Porto Portugal
- Department of Biology Faculty of Sciences University of Porto Porto Portugal
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25
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Wall CA, Koniges GJ, Miller SR. Divergence with gene flow in a population of thermophilic bacteria: a potential role for spatially varying selection. Mol Ecol 2014; 23:3371-83. [PMID: 24863904 DOI: 10.1111/mec.12812] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 05/02/2014] [Accepted: 05/06/2014] [Indexed: 01/14/2023]
Abstract
A fundamental goal of evolutionary biology is to understand how ecological diversity arises and is maintained in natural populations. We have investigated the contributions of gene flow and divergent selection to the distribution of genetic variation in an ecologically differentiated population of a thermophilic cyanobacterium (Mastigocladus laminosus) found along the temperature gradient of a nitrogen-limited stream in Yellowstone National Park. For most loci sampled, gene flow appears to be sufficient to prevent substantial genetic divergence. However, one locus (rfbC) exhibited a comparatively low migration rate as well as other signatures expected for a gene experiencing spatially varying selection, including an excess of common variants, an elevated level of polymorphism and extreme genetic differentiation along the gradient. rfbC is part of an expression island involved in the production of the polysaccharide component of the protective envelope of the heterocyst, the specialized nitrogen-fixing cell of these bacteria. SNP genotyping in the vicinity of rfbC revealed a ~5-kbp region including a gene content polymorphism that is tightly associated with environmental temperature and therefore likely contains the target of selection. Two genes have been deleted both in the predominant haplotype found in the downstream region of White Creek and in strains from other Yellowstone populations of M. laminosus, which may result in the production of heterocysts with different envelope properties. This study implicates spatially varying selection in the maintenance of variation related to thermal performance at White Creek despite on-going or recent gene flow.
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Affiliation(s)
- Christopher A Wall
- Division of Biological Sciences, 32 Campus Dr. #4824, The University of Montana Missoula, MT, 59812-4824, USA
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26
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Park JJ, Lechno-Yossef S, Wolk CP, Vieille C. Cell-specific gene expression in Anabaena variabilis grown phototrophically, mixotrophically, and heterotrophically. BMC Genomics 2013; 14:759. [PMID: 24191963 PMCID: PMC4046671 DOI: 10.1186/1471-2164-14-759] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 10/26/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND When the filamentous cyanobacterium Anabaena variabilis grows aerobically without combined nitrogen, some vegetative cells differentiate into N2-fixing heterocysts, while the other vegetative cells perform photosynthesis. Microarrays of sequences within protein-encoding genes were probed with RNA purified from extracts of vegetative cells, from isolated heterocysts, and from whole filaments to investigate transcript levels, and carbon and energy metabolism, in vegetative cells and heterocysts in phototrophic, mixotrophic, and heterotrophic cultures. RESULTS Heterocysts represent only 5% to 10% of cells in the filaments. Accordingly, levels of specific transcripts in vegetative cells were with few exceptions very close to those in whole filaments and, also with few exceptions (e.g., nif1 transcripts), levels of specific transcripts in heterocysts had little effect on the overall level of those transcripts in filaments. In phototrophic, mixotrophic, and heterotrophic growth conditions, respectively, 845, 649, and 846 genes showed more than 2-fold difference (p < 0.01) in transcript levels between vegetative cells and heterocysts. Principal component analysis showed that the culture conditions tested affected transcript patterns strongly in vegetative cells but much less in heterocysts. Transcript levels of the genes involved in phycobilisome assembly, photosynthesis, and CO2 assimilation were high in vegetative cells in phototrophic conditions, and decreased when fructose was provided. Our results suggest that Gln, Glu, Ser, Gly, Cys, Thr, and Pro can be actively produced in heterocysts. Whether other protein amino acids are synthesized in heterocysts is unclear. Two possible components of a sucrose transporter were identified that were upregulated in heterocysts in two growth conditions. We consider it likely that genes with unknown function represent a larger fraction of total transcripts in heterocysts than in vegetative cells across growth conditions. CONCLUSIONS This study provides the first comparison of transcript levels in heterocysts and vegetative cells from heterocyst-bearing filaments of Anabaena. Although the data presented do not give a complete picture of metabolism in either type of cell, they provide a metabolic scaffold on which to build future analyses of cell-specific processes and of the interactions of the two types of cells.
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Affiliation(s)
- Jeong-Jin Park
- />Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824 USA
- />Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI 48824 USA
- />Present address: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164 USA
| | - Sigal Lechno-Yossef
- />Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824 USA
- />MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
| | - Coleman Peter Wolk
- />Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824 USA
- />MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
- />Department of Plant Biology, Michigan State University, East Lansing, MI 48824 USA
| | - Claire Vieille
- />Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824 USA
- />Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI 48824 USA
- />Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, MI 48824 USA
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27
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González A, Valladares A, Peleato ML, Fillat MF. FurA influences heterocyst differentiation in Anabaena sp. PCC 7120. FEBS Lett 2013; 587:2682-90. [PMID: 23851073 DOI: 10.1016/j.febslet.2013.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/01/2013] [Accepted: 07/02/2013] [Indexed: 01/14/2023]
Abstract
In Anabaena sp. PCC 7120, FurA is a global transcriptional regulator whose expression is strongly induced by NtcA in proheterocysts and remains stably expressed in mature heterocysts. In the present study, overexpression of furA partially suppressed heterocyst differentiation by impairing morphogenesis at an early stage. Recombinant purified FurA specifically bound in vitro to the promoter regions of ntcA, while quantitative RT-PCR analyses indicated that furA overexpression strongly affected the transient increase of ntcA expression that occurs shortly after nitrogen step-down. Overall, the results suggest a connection between iron homeostasis and heterocyst differentiation via FurA, by modulating the expression of ntcA.
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Affiliation(s)
- Andrés González
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
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28
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Tan H, Wan S, Liu PQ, Wang L, Zhang CC, Chen WL. Alr5068, a Low-Molecular-Weight protein tyrosine phosphatase, is involved in formation of the heterocysts polysaccharide layer in the cyanobacterium Anabaena sp. PCC 7120. Res Microbiol 2013; 164:875-85. [PMID: 23827083 DOI: 10.1016/j.resmic.2013.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 05/14/2013] [Indexed: 11/25/2022]
Abstract
The filamentous cyanobacterium Anabaena sp. PCC 7120 forms nitrogen-fixing heterocysts after deprivation of combined nitrogen. Under such conditions, vegetative cells provide heterocysts with photosynthate and receive fixed nitrogen from the latter. Heterocyst envelope contains a glycolipid layer and a polysaccharide layer to restrict the diffusion of oxygen into heterocysts. Low-Molecular-Weight protein tyrosine phosphatases (LMW-PTPs) are involved in the biosynthesis of exopolysaccharides in bacteria. Alr5068, a protein from Anabaena sp. PCC 7120, shows significant sequence similarity with LMW-PTPs. In this study we characterized the enzymatic properties of Alr5068 and showed that it can dephosphorylate several autophosphorylated tyrosine kinases (Alr2856, Alr3059 and All4432) of Anabaena sp. PCC 7120 in vitro. Several conserved residues among LMW-PTPs are shown to be essential for the phosphatase activity of Alr5068. Overexpression of alr5068 results in a strain unable to survive under diazotrophic conditions, with the formation of morphologically mature heterocysts detached from the filaments. Overexpression of an alr5068 allele that lost phosphatase activity led to the formation of heterocyst with an impaired polysaccharide layer. The alr5068 gene was upregulated after nitrogen step-down and its mutation affected the expression of hepA and hepC, two genes necessary for the formation of the heterocyst envelope polysaccharide (HEP) layer. Our results suggest that Alr5068 is associated with the production of HEP in Anabaena sp. PCC 7120.
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Affiliation(s)
- Hui Tan
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, 430070 Wuhan, China.
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29
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Cell wall amidase AmiC1 is required for cellular communication and heterocyst development in the cyanobacterium Anabaena PCC 7120 but not for filament integrity. J Bacteriol 2012; 194:5218-27. [PMID: 22821973 DOI: 10.1128/jb.00912-12] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Filamentous cyanobacteria of the order Nostocales display typical properties of multicellular organisms. In response to nitrogen starvation, some vegetative cells differentiate into heterocysts, where fixation of N(2) takes place. Heterocysts provide a micro-oxic compartment to protect nitrogenase from the oxygen produced by the vegetative cells. Differentiation involves fundamental remodeling of the gram-negative cell wall by deposition of a thick envelope and by formation of a neck-like structure at the contact site to the vegetative cells. Cell wall-hydrolyzing enzymes, like cell wall amidases, are involved in peptidoglycan maturation and turnover in unicellular bacteria. Recently, we showed that mutation of the amidase homologue amiC2 gene in Nostoc punctiforme ATCC 29133 distorts filament morphology and function. Here, we present the functional characterization of two amiC paralogues from Anabaena sp. strain PCC 7120. The amiC1 (alr0092) mutant was not able to differentiate heterocysts or to grow diazotrophically, whereas the amiC2 (alr0093) mutant did not show an altered phenotype under standard growth conditions. In agreement, fluorescence recovery after photobleaching (FRAP) studies showed a lack of cell-cell communication only in the AmiC1 mutant. Green fluorescent protein (GFP)-tagged AmiC1 was able to complement the mutant phenotype to wild-type properties. The protein localized in the septal regions of newly dividing cells and at the neck region of differentiating heterocysts. Upon nitrogen step-down, no mature heterocysts were developed in spite of ongoing heterocyst-specific gene expression. These results show the dependence of heterocyst development on amidase function and highlight a pivotal but so far underestimated cellular process, the remodeling of peptidoglycan, for the biology of filamentous cyanobacteria.
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A major facilitator superfamily protein, HepP, is involved in formation of the heterocyst envelope polysaccharide in the cyanobacterium Anabaena sp. strain PCC 7120. J Bacteriol 2012; 194:4677-87. [PMID: 22753066 DOI: 10.1128/jb.00489-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Some filamentous cyanobacteria such as Anabaena sp. strain PCC 7120 produce cells, termed heterocysts, specialized in nitrogen fixation. Heterocysts bear a thick envelope containing an inner layer of glycolipids and an outer layer of polysaccharide that restrict the diffusion of air (including O(2)) into the heterocyst. Anabaena sp. mutants impaired in production of either of those layers show a Fox(-) phenotype (requiring fixed nitrogen for growth under oxic conditions). We have characterized a set of transposon-induced Fox(-) mutants in which transposon Tn5-1063 was inserted into the Anabaena sp. chromosome open reading frame all1711 which encodes a predicted membrane protein that belongs to the major facilitator superfamily (MFS). These mutants showed higher nitrogenase activities under anoxic than under oxic conditions and altered sucrose uptake. Electron microscopy and alcian blue staining showed a lack of the heterocyst envelope polysaccharide (Hep) layer. Northern blot and primer extension analyses showed that, in a manner dependent on the nitrogen-control transcription factor NtcA, all1711 was strongly induced after nitrogen step-down. Confocal microscopy of an Anabaena sp. strain producing an All1711-green fluorescent protein (All1711-GFP) fusion protein showed induction in all cells of the filament but at higher levels in differentiating heterocysts. All1711-GFP was located in the periphery of the cells, consistent with All1711 being a cytoplasmic membrane protein. Expression of all1711 from the P(glnA) promoter in a multicopy plasmid led to production of a presumptive exopolysaccharide by vegetative cells. These results suggest that All1711, which we denote HepP, is involved in transport of glycoside(s), with a specific physiological role in production of Hep.
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Taton A, Lis E, Adin DM, Dong G, Cookson S, Kay SA, Golden SS, Golden JW. Gene transfer in Leptolyngbya sp. strain BL0902, a cyanobacterium suitable for production of biomass and bioproducts. PLoS One 2012; 7:e30901. [PMID: 22292073 PMCID: PMC3265524 DOI: 10.1371/journal.pone.0030901] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/23/2011] [Indexed: 11/18/2022] Open
Abstract
Current cyanobacterial model organisms were not selected for their growth traits or potential for the production of renewable biomass, biofuels, or other products. The cyanobacterium strain BL0902 emerged from a search for strains with superior growth traits. Morphology and 16S rRNA sequence placed strain BL0902 in the genus Leptolyngbya. Leptolyngbya sp. strain BL0902 (hereafter Leptolyngbya BL0902) showed robust growth at temperatures from 22°C to 40°C and tolerated up to 0.5 M NaCl, 32 mM urea, high pH, and high solar irradiance. Its growth rate under outdoor conditions rivaled Arthrospira (“pirulina” strains. Leptolyngbya BL0902 accumulated higher lipid content and a higher proportion of monounsaturated fatty acids than Arthrospira strains. In addition to these desirable qualities, Leptolyngbya BL0902 is amenable to genetic engineering that is reliable, efficient, and stable. We demonstrated conjugal transfer from Escherichia coli of a plasmid based on RSF1010 and expression of spectinomycin/streptomycin resistance and yemGFP reporter transgenes. Conjugation efficiency was investigated in biparental and triparental matings with and without a “elper”plasmid that carries DNA methyltransferase genes, and with two different conjugal plasmids. We also showed that Leptolyngbya BL0902 is amenable to transposon mutagenesis with a Tn5 derivative. To facilitate genetic manipulation of Leptolyngbya BL0902, a conjugal plasmid vector was engineered to carry a trc promoter upstream of a Gateway recombination cassette. These growth properties and genetic tools position Leptolyngbya BL0902 as a model cyanobacterial production strain.
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Affiliation(s)
- Arnaud Taton
- Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Ewa Lis
- Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Dawn M. Adin
- Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Guogang Dong
- Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Scott Cookson
- Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Steve A. Kay
- Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - Susan S. Golden
- Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
| | - James W. Golden
- Division of Biological Sciences, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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Global transcription profiles of the nitrogen stress response resulting in heterocyst or hormogonium development in Nostoc punctiforme. J Bacteriol 2011; 193:6874-86. [PMID: 22001509 DOI: 10.1128/jb.05999-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The filamentous cyanobacterium Nostoc punctiforme differentiates from vegetative cells into three distinct cell types, heterocysts, hormogonia, and akinetes, in response to different stimuli. Cultures growing with ammonium can be induced to form hormogonia or heterocysts upon removal of the combined nitrogen. A DNA microarray consisting of 94% of the open reading frames predicted from the 9.059-Mb N. punctiforme genome was used to generate a global transcription data set consisting of seven time points over a 24-h period of nitrogen deprivation, which results in heterocyst formation. This data set was compared to a similarly generated data set of nitrogen-starved N. punctiforme resulting in hormogonium formation that had previously been published (E. L. Campbell, H. Christman, and J. C. Meeks, J. Bacteriol. 190:7382-7391, 2008). The transition from vegetative cells to either heterocysts or hormogonia resulted in rapid and sustained expression of genes required for utilization of alternate nitrogen sources. Overall, 1,036 and 1,762 genes were found to be differentially transcribed during the heterocyst and hormogonium time courses, respectively, as analyzed with the Bayesian user-friendly software for analyzing time series microarray experiments (BATS). Successive transcription of heterocyst regulatory, structural, and functional genes occurred over the 24 h required to form a functional heterocyst. During hormogonium differentiation, some heterocyst structural and functional genes were upregulated, while the heterocyst master regulator hetR was downregulated. There are commonalities in differential expression between cells bound for differentiation into heterocysts or hormogonia, yet the two paths are distinguished by their developmentally specific transcription profiles.
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Mutations in genes patA and patL of Anabaena sp. strain PCC 7120 result in similar phenotypes, and the proteins encoded by those genes may interact. J Bacteriol 2011; 193:6070-4. [PMID: 21890704 DOI: 10.1128/jb.05523-11] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PatA resembles a response regulator protein with a defective DNA-binding domain, and PatL (All3305) is a pentapeptide repeat protein. A yeast two-hybrid library identified PatL as a protein with which PatA may interact. Heterocysts of patA and patL Anabaena sp. form nearly exclusively terminally in long filaments, further linking the genes.
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Flaherty BL, Van Nieuwerburgh F, Head SR, Golden JW. Directional RNA deep sequencing sheds new light on the transcriptional response of Anabaena sp. strain PCC 7120 to combined-nitrogen deprivation. BMC Genomics 2011; 12:332. [PMID: 21711558 PMCID: PMC3141674 DOI: 10.1186/1471-2164-12-332] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 06/28/2011] [Indexed: 11/13/2022] Open
Abstract
Background Cyanobacteria are potential sources of renewable chemicals and biofuels and serve as model organisms for bacterial photosynthesis, nitrogen fixation, and responses to environmental changes. Anabaena (Nostoc) sp. strain PCC 7120 (hereafter Anabaena) is a multicellular filamentous cyanobacterium that can "fix" atmospheric nitrogen into ammonia when grown in the absence of a source of combined nitrogen. Because the nitrogenase enzyme is oxygen sensitive, Anabaena forms specialized cells called heterocysts that create a microoxic environment for nitrogen fixation. We have employed directional RNA-seq to map the Anabaena transcriptome during vegetative cell growth and in response to combined-nitrogen deprivation, which induces filaments to undergo heterocyst development. Our data provide an unprecedented view of transcriptional changes in Anabaena filaments during the induction of heterocyst development and transition to diazotrophic growth. Results Using the Illumina short read platform and a directional RNA-seq protocol, we obtained deep sequencing data for RNA extracted from filaments at 0, 6, 12, and 21 hours after the removal of combined nitrogen. The RNA-seq data provided information on transcript abundance and boundaries for the entire transcriptome. From these data, we detected novel antisense transcripts within the UTRs (untranslated regions) and coding regions of key genes involved in heterocyst development, suggesting that antisense RNAs may be important regulators of the nitrogen response. In addition, many 5' UTRs were longer than anticipated, sometimes extending into upstream open reading frames (ORFs), and operons often showed complex structure and regulation. Finally, many genes that had not been previously identified as being involved in heterocyst development showed regulation, providing new candidates for future studies in this model organism. Conclusions Directional RNA-seq data were obtained that provide comprehensive mapping of transcript boundaries and abundance for all transcribed RNAs in Anabaena filaments during the response to nitrogen deprivation. We have identified genes and noncoding RNAs that are transcriptionally regulated during heterocyst development. These data provide detailed information on the Anabaena transcriptome as filaments undergo heterocyst development and begin nitrogen fixation.
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Affiliation(s)
- Britt L Flaherty
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0116, USA
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Identification of ten Anabaena sp. genes that under aerobic conditions are required for growth on dinitrogen but not for growth on fixed nitrogen. J Bacteriol 2011; 193:3482-9. [PMID: 21602343 DOI: 10.1128/jb.05010-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heterocysts are specialized cells required for aerobic fixation of dinitrogen by certain filamentous cyanobacteria. Numerous genes involved in the differentiation and function of heterocysts in Anabaena sp. strain PCC 7120 have been identified by mutagenizing and screening for mutants that require fixed nitrogen for growth in the presence of oxygen. We have verified that 10 Anabaena sp. genes, all1338, all1591, alr1728, all3278, all3520, all3582, all3850, all4019, alr4311, and all4388, identified initially by transposon mutagenesis, are such genes by complementing or reconstructing the original mutation and by determining whether the mutant phenotype might be due to a polar effect of the transposon. Elucidation of the roles of these genes should enhance understanding of heterocyst biology.
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Mella-Herrera RA, Neunuebel MR, Kumar K, Saha SK, Golden JW. The sigE gene is required for normal expression of heterocyst-specific genes in Anabaena sp. strain PCC 7120. J Bacteriol 2011; 193:1823-32. [PMID: 21317330 PMCID: PMC3133031 DOI: 10.1128/jb.01472-10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 01/31/2011] [Indexed: 11/20/2022] Open
Abstract
The filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 produces specialized cells for nitrogen fixation called heterocysts. Previous work showed that the group 2 sigma factor sigE (alr4249; previously called sigF) is upregulated in differentiating heterocysts 16 h after nitrogen step-down. We now show that the sigE gene is required for normal heterocyst development and normal expression levels of several heterocyst-specific genes. Mobility shift assays showed that the transcription factor NtcA binds to sites in the upstream region of sigE and that this binding is enhanced by 2-oxoglutarate (2-OG). Deletions of the region containing the NtcA binding sites in P(sigE)-gfp reporter plasmids showed that the sites contribute to normal developmental regulation but are not essential for upregulation in heterocysts. Northern RNA blot analysis of nifH mRNA revealed delayed and reduced transcript levels during heterocyst differentiation in a sigE mutant background. Quantitative reverse transcription-PCR (qRT-PCR) analyses of the sigE mutant showed lower levels of transcripts for nifH, fdxH, and hglE2 but normal levels for hupL. We developed a P(nifHD)-gfp reporter construct that showed strong heterocyst-specific expression. Time-lapse microscopy of the P(nifHD)-gfp reporter in a sigE mutant background showed delayed development and undetectable green fluorescent protein (GFP) fluorescence. Overexpression of sigE caused accelerated heterocyst development, an increased heterocyst frequency, and premature expression of GFP fluorescence from the P(nifHD)-gfp reporter.
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Affiliation(s)
- Rodrigo A. Mella-Herrera
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
- Division of Biological Sciences, University of California—San Diego, La Jolla, California 92093-0116
| | - M. Ramona Neunuebel
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - Krithika Kumar
- Department of Biology, Texas A&M University, College Station, Texas 77843-3258
| | - Sushanta K. Saha
- Division of Biological Sciences, University of California—San Diego, La Jolla, California 92093-0116
| | - James W. Golden
- Division of Biological Sciences, University of California—San Diego, La Jolla, California 92093-0116
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Mella-Herrera RA, Neunuebel MR, Golden JW. Anabaena sp. strain PCC 7120 conR contains a LytR-CpsA-Psr domain, is developmentally regulated, and is essential for diazotrophic growth and heterocyst morphogenesis. MICROBIOLOGY-SGM 2010; 157:617-626. [PMID: 21088107 DOI: 10.1099/mic.0.046128-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The conR (all0187) gene of the filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 is predicted to be part of a family of proteins that contain the LytR-CpsA-Psr domain associated with septum formation and cell wall maintenance. The conR gene was originally misannotated as a transcription regulator. Northern RNA blot analysis showed that conR expression was upregulated 8 h after nitrogen step-down. Fluorescence microscopy of a P(conR)-gfp reporter strain revealed increased GFP fluorescence in proheterocysts and heterocysts beginning 9 h after nitrogen step-down. Insertional inactivation of conR caused a septum-formation defect of vegetative cells grown in nitrate-containing medium. In nitrate-free medium, mutant filaments formed abnormally long heterocysts and were defective for diazotrophic growth. Septum formation between heterocysts and adjacent vegetative cells was abnormal, often with one or both poles of the heterocysts appearing partially open. In a conR mutant, expression of nifH was delayed after nitrogen step-down and nitrogenase activity was approximately 70 % of wild-type activity, indicating that heterocysts of the conR mutant strain are partially functional. We hypothesize that the diazotrophic growth defect is caused by an inability of the heterocysts to transport fixed nitrogen to the neighbouring vegetative cells.
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Affiliation(s)
- Rodrigo A Mella-Herrera
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0116, USA.,Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA
| | - M Ramona Neunuebel
- Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA
| | - James W Golden
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0116, USA
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Comparison of envelope-related genes in unicellular and filamentous cyanobacteria. Comp Funct Genomics 2010:25751. [PMID: 18253473 PMCID: PMC2211374 DOI: 10.1155/2007/25751] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Revised: 02/17/2007] [Accepted: 06/03/2007] [Indexed: 11/18/2022] Open
Abstract
To elucidate the evolution of cyanobacterial envelopes and the relation between gene content and environmental adaptation, cell envelope structures and components of unicellular and filamentous cyanobacteria were analyzed in comparative genomics. Hundreds of envelope biogenesis genes were divided into 5 major groups and annotated according to their conserved domains and phylogenetic profiles. Compared to unicellular species, the gene numbers of filamentous cyanobacteria expanded due to genome enlargement effect, but only few gene families amplified disproportionately, such as those encoding waaG and glycosyl transferase 2. Comparison of envelope genes among various species suggested that the significant variance of certain cyanobacterial envelope biogenesis genes should be the response to their environmental adaptation, which might be also related to the emergence of filamentous shapes with some new functions.
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Higa KC, Callahan SM. Ectopic expression of hetP can partially bypass the need for hetR in heterocyst differentiation by Anabaena sp. strain PCC 7120. Mol Microbiol 2010; 77:562-74. [DOI: 10.1111/j.1365-2958.2010.07257.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Many multicellular cyanobacteria produce specialized nitrogen-fixing heterocysts. During diazotrophic growth of the model organism Anabaena (Nostoc) sp. strain PCC 7120, a regulated developmental pattern of single heterocysts separated by about 10 to 20 photosynthetic vegetative cells is maintained along filaments. Heterocyst structure and metabolic activity function together to accommodate the oxygen-sensitive process of nitrogen fixation. This article focuses on recent research on heterocyst development, including morphogenesis, transport of molecules between cells in a filament, differential gene expression, and pattern formation.
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Affiliation(s)
- Krithika Kumar
- Department of Biology, Texas A&M University, College Station, 77843, USA
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Stucken K, John U, Cembella A, Murillo AA, Soto-Liebe K, Fuentes-Valdés JJ, Friedel M, Plominsky AM, Vásquez M, Glöckner G. The smallest known genomes of multicellular and toxic cyanobacteria: comparison, minimal gene sets for linked traits and the evolutionary implications. PLoS One 2010; 5:e9235. [PMID: 20169071 PMCID: PMC2821919 DOI: 10.1371/journal.pone.0009235] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 01/14/2010] [Indexed: 11/24/2022] Open
Abstract
Cyanobacterial morphology is diverse, ranging from unicellular spheres or rods to multicellular structures such as colonies and filaments. Multicellular species represent an evolutionary strategy to differentiate and compartmentalize certain metabolic functions for reproduction and nitrogen (N2) fixation into specialized cell types (e.g. akinetes, heterocysts and diazocytes). Only a few filamentous, differentiated cyanobacterial species, with genome sizes over 5 Mb, have been sequenced. We sequenced the genomes of two strains of closely related filamentous cyanobacterial species to yield further insights into the molecular basis of the traits of N2 fixation, filament formation and cell differentiation. Cylindrospermopsis raciborskii CS-505 is a cylindrospermopsin-producing strain from Australia, whereas Raphidiopsis brookii D9 from Brazil synthesizes neurotoxins associated with paralytic shellfish poisoning (PSP). Despite their different morphology, toxin composition and disjunct geographical distribution, these strains form a monophyletic group. With genome sizes of approximately 3.9 (CS-505) and 3.2 (D9) Mb, these are the smallest genomes described for free-living filamentous cyanobacteria. We observed remarkable gene order conservation (synteny) between these genomes despite the difference in repetitive element content, which accounts for most of the genome size difference between them. We show here that the strains share a specific set of 2539 genes with >90% average nucleotide identity. The fact that the CS-505 and D9 genomes are small and streamlined compared to those of other filamentous cyanobacterial species and the lack of the ability for heterocyst formation in strain D9 allowed us to define a core set of genes responsible for each trait in filamentous species. We presume that in strain D9 the ability to form proper heterocysts was secondarily lost together with N2 fixation capacity. Further comparisons to all available cyanobacterial genomes covering almost the entire evolutionary branch revealed a common minimal gene set for each of these cyanobacterial traits.
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Affiliation(s)
- Karina Stucken
- Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
- Millenium Nucleus EMBA, Santiago, Chile
| | - Uwe John
- Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
| | - Allan Cembella
- Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany
| | - Alejandro A. Murillo
- Department of Molecular Genetic and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millenium Nucleus EMBA, Santiago, Chile
| | - Katia Soto-Liebe
- Department of Molecular Genetic and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millenium Nucleus EMBA, Santiago, Chile
| | - Juan J. Fuentes-Valdés
- Department of Molecular Genetic and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millenium Nucleus EMBA, Santiago, Chile
| | - Maik Friedel
- Leibniz Institute for Age Research-Fritz Lipmann Institute, Jena, Germany
| | - Alvaro M. Plominsky
- Department of Molecular Genetic and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millenium Nucleus EMBA, Santiago, Chile
| | - Mónica Vásquez
- Department of Molecular Genetic and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Millenium Nucleus EMBA, Santiago, Chile
- * E-mail: (MV); (GG)
| | - Gernot Glöckner
- Leibniz Institute for Age Research-Fritz Lipmann Institute, Jena, Germany
- Institute for Biochemistry I, University of Cologne, Cologne, Germany
- Leibniz Institute for Freshwater Ecology and Inland Fisheries, Berlin, Germany
- * E-mail: (MV); (GG)
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Flores E, Herrero A. Compartmentalized function through cell differentiation in filamentous cyanobacteria. Nat Rev Microbiol 2010; 8:39-50. [PMID: 19966815 DOI: 10.1038/nrmicro2242] [Citation(s) in RCA: 298] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Within the wide biodiversity that is found in the bacterial world, Cyanobacteria represents a unique phylogenetic group that is responsible for a key metabolic process in the biosphere - oxygenic photosynthesis - and that includes representatives exhibiting complex morphologies. Many cyanobacteria are multicellular, growing as filaments of cells in which some cells can differentiate to carry out specialized functions. These differentiated cells include resistance and dispersal forms as well as a metabolically specialized form that is devoted to N(2) fixation, known as the heterocyst. In this Review we address cyanobacterial intercellular communication, the supracellular structure of the cyanobacterial filament and the basic principles that govern the process of heterocyst differentiation.
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Affiliation(s)
- Enrique Flores
- Instituto de Bioqumica Vegetal y Fotosntesis, CSIC and Universidad de Sevilla, Amrico Vespucio 49, E41092 Seville, Spain.
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Nicolaisen K, Hahn A, Schleiff E. The cell wall in heterocyst formation byAnabaenasp. PCC 7120. J Basic Microbiol 2009; 49:5-24. [DOI: 10.1002/jobm.200800300] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Zhang W, Du Y, Khudyakov I, Fan Q, Gao H, Ning D, Wolk CP, Xu X. A gene cluster that regulates both heterocyst differentiation and pattern formation in Anabaena sp. strain PCC 7120. Mol Microbiol 2008; 66:1429-43. [PMID: 18045384 DOI: 10.1111/j.1365-2958.2007.05997.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Wild-type Anabaena sp. strain PCC 7120, a filamentous nitrogen-fixing cyanobacterium, produces single heterocysts at semi-regular intervals. asr0100 (patU5) and alr0101 (patU3) are homologous to the 5' and 3' portions of patU of Nostoc punctiforme. alr0099 (hetZ) overlaps the 5' end of patU5. hetZ, patU5 and patU3 were all upregulated, or expressed specifically, in proheterocysts and heterocysts. Mutants of hetZ showed delayed or no heterocyst differentiation. In contrast, a patU3 mutation produced a multiple contiguous heterocyst (Mch) phenotype and restored the formation of otherwise lost intercalary heterocysts in a patA background. Decreasing the expression of patU3 greatly increased the frequency of heterocysts in a mini-patS strain. Two promoter regions and two principal, corresponding transcripts were detected in the hetZ-patU5-patU3 region. Transcription of hetZ was upregulated in a hetZ mutant and downregulated in a patU3 mutant. When mutants hetZ::C.K2 and hetZ::Tn5-1087b were nitrogen-deprived, P(hetC)-gfp was very weakly expressed, and in hetZ::Tn5-1087b, P(hetR)-gfp was relatively strongly expressed in cells that had neither a regular pattern nor altered morphology. We conclude that the hetZ-patU5-patU3 cluster plays an important role in co-ordination of heterocyst differentiation and pattern formation. The presence of homologous clusters in filamentous genera without heterocysts is suggestive of a more general role.
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Affiliation(s)
- Wei Zhang
- The State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
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Moslavac S, Nicolaisen K, Mirus O, Al Dehni F, Pernil R, Flores E, Maldener I, Schleiff E. A TolC-like protein is required for heterocyst development in Anabaena sp. strain PCC 7120. J Bacteriol 2007; 189:7887-95. [PMID: 17720784 PMCID: PMC2168721 DOI: 10.1128/jb.00750-07] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The filamentous cyanobacterium Anabaena sp. strain PCC 7120 forms heterocysts in a semiregular pattern when it is grown on N2 as the sole nitrogen source. The transition from vegetative cells to heterocysts requires marked metabolic and morphological changes. We show that a trimeric pore-forming outer membrane beta-barrel protein belonging to the TolC family, Alr2887, is up-regulated in developing heterocysts and is essential for diazotrophic growth. Mutants defective in Alr2887 did not form the specific glycolipid layer of the heterocyst cell wall, which is necessary to protect nitrogenase from external oxygen. Comparison of the glycolipid contents of wild-type and mutant cells indicated that the protein is not involved in the synthesis of glycolipids but might instead serve as an exporter for the glycolipid moieties or enzymes involved in glycolipid attachment. We propose that Alr2887, together with an ABC transporter like DevBCA, is part of a protein export system essential for assembly of the heterocyst glycolipid layer. We designate the alr2887 gene hgdD (heterocyst glycolipid deposition protein).
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Affiliation(s)
- Suncana Moslavac
- LMU, Department of Biology I, VW-Research Group, Menzinger Str. 67, 80638 München, Germany
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Wolk CP, Fan Q, Zhou R, Huang G, Lechno-Yossef S, Kuritz T, Wojciuch E. Paired cloning vectors for complementation of mutations in the cyanobacterium Anabaena sp. strain PCC 7120. Arch Microbiol 2007; 188:551-63. [PMID: 17639350 DOI: 10.1007/s00203-007-0276-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2007] [Revised: 06/11/2007] [Accepted: 06/16/2007] [Indexed: 11/26/2022]
Abstract
The clones generated in a sequencing project represent a resource for subsequent analysis of the organism whose genome has been sequenced. We describe an interrelated group of cloning vectors that either integrate into the genome or replicate, and that enhance the utility, for developmental and other studies, of the clones used to determine the genomic sequence of the cyanobacterium, Anabaena sp. strain PCC 7120. One integrating vector is a mobilizable BAC vector that was used both to generate bridging clones and to complement transposon mutations. Upon addition of a cassette that permits mobilization and selection, pUC-based sequencing clones can also integrate into the genome and thereupon complement transposon mutations. The replicating vectors are based on cyanobacterial plasmid pDU1, whose sequence we report, and on broad-host-range plasmid RSF1010. The RSF1010- and pDU1-based vectors provide the opportunity to express different genes from either cell-type-specific or -generalist promoters, simultaneously from different plasmids in the same cyanobacterial cells. We show that pDU1 ORF4 and its upstream region play an essential role in the replication and copy number of pDU1, and that ORFs alr2887 and alr3546 (hetF A) of Anabaena sp. are required specifically for fixation of dinitrogen under oxic conditions.
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Affiliation(s)
- C Peter Wolk
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824-1312, USA.
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Wang Y, Lechno-Yossef S, Gong Y, Fan Q, Wolk CP, Xu X. Predicted glycosyl transferase genes located outside the HEP island are required for formation of heterocyst envelope polysaccharide in Anabaena sp. strain PCC 7120. J Bacteriol 2007; 189:5372-8. [PMID: 17483218 PMCID: PMC1951851 DOI: 10.1128/jb.00343-07] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
During maturation, heterocysts form an envelope layer of polysaccharide, called heterocyst envelope polysaccharide (HEP), whose synthesis depends on a cluster of genes, the HEP island, and on an additional, distant gene, hepB, or a gene immediately downstream from hepB. We show that HEP formation depends upon the predicted glycosyl transferase genes all4160 at a third locus and alr3699, which is adjacent to hepB and is cotranscribed with it. Mutations in the histidine kinase genes hepN and hepK appear to silence the promoter of hepB and incompletely down-regulate all4160.
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Affiliation(s)
- Yu Wang
- The State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, People's Republic of China
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Nayar AS, Yamaura H, Rajagopalan R, Risser DD, Callahan SM. FraG is necessary for filament integrity and heterocyst maturation in the cyanobacterium Anabaena sp. strain PCC 7120. MICROBIOLOGY-SGM 2007; 153:601-607. [PMID: 17259632 DOI: 10.1099/mic.0.2006/002535-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that differentiates nitrogen-fixing heterocysts when fixed nitrogen becomes growth limiting in the medium. The gene alr2338 (designated fraG herein), located immediately upstream of the master regulator of differentiation hetR, was identified in a genetic screen for mutants unable to grow diazotrophically. Filaments with a mutation in fraG were unable to fix nitrogen or synthesize heterocyst-specific glycolipids, and they fragmented initially to approximately nine cells in length at 24 h after induction of heterocyst development and eventually became unicellular. The fragmentation phenotype could be duplicated in the presence of fixed nitrogen when differentiation of heterocysts was elicited by overexpression of hetR, suggesting that a defect in differentiation, and not a lack of fixed nitrogen in the medium, was the more direct cause of fragmentation. An intact fraG gene was necessary for differentiation of mature heterocysts, but was not required for proper pattern formation, as indicated by a normal pattern of expression of hetR in a fraG mutant. A transcriptional GFP reporter fusion indicated that the level of expression of fraG was low in vegetative cells in both nitrogen-replete and nitrogen-free media, and was induced in heterocysts. fraG appears to play a role in filament integrity and differentiation of proheterocysts into mature heterocysts.
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Affiliation(s)
- Asha S Nayar
- Department of Microbiology, University of Hawaii, Honolulu, HI 96822, USA
| | - Hiroshi Yamaura
- Department of Microbiology, University of Hawaii, Honolulu, HI 96822, USA
| | - Ramya Rajagopalan
- Department of Microbiology, University of Hawaii, Honolulu, HI 96822, USA
| | - Douglas D Risser
- Department of Microbiology, University of Hawaii, Honolulu, HI 96822, USA
| | - Sean M Callahan
- Department of Microbiology, University of Hawaii, Honolulu, HI 96822, USA
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Jang J, Wang L, Jeanjean R, Zhang CC. PrpJ, a PP2C-type protein phosphatase located on the plasma membrane, is involved in heterocyst maturation in the cyanobacterium Anabaena sp. PCC 7120. Mol Microbiol 2007; 64:347-58. [PMID: 17371502 DOI: 10.1111/j.1365-2958.2007.05654.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein phosphatases play important roles in the regulation of cell growth, division and differentiation. The cyanobacterium Anabaena PCC 7120 is able to differentiate heterocysts specialized in nitrogen fixation. To protect the nitrogenase from inactivation by oxygen, heterocyst envelope possesses a layer of polysaccharide and a layer of glycolipids. In the present study, we characterized All1731 (PrpJ), a protein phosphatase from Anabaena PCC 7120. prpJ was constitutively expressed in both vegetative cells and heterocysts. Under diazotrophic conditions, the mutant DeltaprpJ (S20) did not grow, lacked only one of the two heterocyst glycolipids, and fragmented extensively at the junctions between developing cells and vegetative cells. No heterocyst glycolipid layer could be observed in the mutant by electron microscopy. The inactivation of prpJ affected the expression of hglE(A) and nifH, two genes necessary for the formation of the glycolipid layer of heterocysts and the nitrogenase respectively. PrpJ displayed a phosphatase activity characteristic of PP2C-type protein phosphatases, and was localized on the plasma membrane. The function of prpJ establishes a new control point for heterocyst maturation because it regulates the synthesis of only one of the two heterocyst glycolipids while all other genes so far analysed regulate the synthesis of both heterocyst glycolipids.
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Affiliation(s)
- Jichan Jang
- Laboratoire de Chimie Bactérienne, CNRS-UPR9043, Institut de Biologie Structurale et Microbiologie, 31 chemin Joseph Aiguier, 13402 Marseille cedex 20, France
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