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Cai Y, Dong J, Huang J, He J, Hu Y, Sui Z, Tang P. The cyclic AMP (cAMP) phosphodiesterase CpdA required for growth, biofilm formation, motility and pathogenicity of Edwardsiella piscicida. Microb Pathog 2024; 188:106545. [PMID: 38244636 DOI: 10.1016/j.micpath.2024.106545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/09/2024] [Accepted: 01/14/2024] [Indexed: 01/22/2024]
Abstract
Edwardsiella piscicida is a severe fish pathogen with wide host range, causing the huge economic losses in the aquaculture industry. Cyclic adenosine monophosphate (cAMP) as an important second messenger regulates the physiological and behavioral responses to environmental cues in eukaryotic and prokaryotic. The intracellular level of cAMP for effective activity is tightly controlled by the synthesis of adenylate cyclase, excretion and degradation of phosphodiesterase. In this study, we identified and characterized a class III cAMP phosphodiesterase, named as CpdA, in the E. piscicida. To investigate the role of CpdA in the physiology and pathogenicity, we constructed the in-frame deletion mutant of cpdA of E. piscicida, TX01ΔcpdA. The results showed that TX01ΔcpdA accumulated the higher intracellular cAMP concentration than TX01, indicating that CpdA exerted the hydrolysis of cAMP. In addition, compared to the TX01, the TX01ΔcpdA slowed growth rate, diminished biofilm formation and lost motility. More importantly, pathogenicity analysis confirmed that TX01ΔcpdA significantly impaired the ability of invading the epithelial cells, reproduction in macrophages, tissues dissemination and lethality for healthy tilapias. The most of lost properties of TX01ΔcpdA were restored partially or fully by the introduction of cpdA gene. These results suggest that cpdA is required for regulation of the physiology and virulence of E. piscicida.
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Affiliation(s)
- Yidong Cai
- School of Life and Health, Hainan University, Haikou, 570228, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou, 571101, China
| | - Jinggang Dong
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou, 571101, China
| | - Jianqiang Huang
- Zhanjiang Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, 524013, China
| | - Jiaojiao He
- School of Life and Health, Hainan University, Haikou, 570228, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou, 571101, China
| | - Yonghua Hu
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; Key Laboratory of Biology and Genetic Resources of Tropical Crops of Hainan Province, Hainan Institute for Tropical Agricultural Resources, Haikou, 571101, China; Hainan Provincial Key Laboratory for Functional Components Research and Utilization of Marine Bio-resources, Haikou, 571101, China; Zhanjiang Experimental Station, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, 524013, China
| | - Zhihai Sui
- School of Life Science, Linyi University, Linyi, 276000, China.
| | - Ping Tang
- State Key Laboratory of Conservation and Utilization of Biologícal Resources of Yunnan, College of Plant Protection, Yunnan Agricultural University, Kunming, 650201, China.
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2
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Light dependent synthesis of a nucleotide second messenger controls the motility of a spirochete bacterium. Sci Rep 2022; 12:6825. [PMID: 35474318 PMCID: PMC9043183 DOI: 10.1038/s41598-022-10556-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/11/2022] [Indexed: 11/24/2022] Open
Abstract
Nucleotide second messengers are universally crucial factors for the signal transduction of various organisms. In prokaryotes, cyclic nucleotide messengers are involved in the bacterial life cycle and in functions such as virulence and biofilm formation, mainly via gene regulation. Here, we show that the swimming motility of the soil bacterium Leptospira kobayashii is rapidly modulated by light stimulation. Analysis of a loss-of-photoresponsivity mutant obtained by transposon random mutagenesis identified the novel sensory gene, and its expression in Escherichia coli through codon optimization elucidated the light-dependent synthesis of cyclic adenosine monophosphate (cAMP). GFP labeling showed the localization of the photoresponsive enzyme at the cell poles where flagellar motors reside. These findings suggest a new role for cAMP in rapidly controlling the flagella-dependent motility of Leptospira and highlight the global distribution of the newly discovered photoactivated cyclase among diverse microbial species.
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Bantu L, Chauhan S, Srikumar A, Hirakawa Y, Suzuki I, Hagemann M, Prakash JSS. A membrane-bound cAMP receptor protein, SyCRP1 mediates inorganic carbon response in Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2022; 1865:194803. [PMID: 35272049 DOI: 10.1016/j.bbagrm.2022.194803] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 02/24/2022] [Accepted: 02/27/2022] [Indexed: 06/14/2023]
Abstract
The availability of inorganic carbon (Ci) as the source for photosynthesis is fluctuating in aquatic environments. Despite the involvement of transcriptional regulators CmpR and NdhR in regulating genes encoding Ci transporters at limiting CO2, the Ci-sensing mechanism is largely unknown among cyanobacteria. Here we report that a cAMP-dependent transcription factor SyCRP1 mediates Ci response in Synechocystis. The mutant ∆sycrp1 exhibited a slow-growth phenotype and reduced maximum rate of bicarbonate-dependent photosynthetic electron transport (Vmax) compared to wild-type at the scarcity of CO2. The number of carboxysomes was decreased significantly in the ∆sycrp1 at low CO2 consistent with its reduced Vmax. The DNA microarray analysis revealed the upregulation of genes encoding Ci transporters in ∆sycrp1. The membrane-localized SyCRP1 was released into the cytosol in wild-type cells shifted from low to high CO2 or upon cAMP treatment. Soluble His-tagged SyCRP1 was shown to target DNA-binding sites upstream of the Ci-regulated genes sbtA and ccmK3. In addition, cAMP enhanced the binding of SyCRP1 to its target sites. Our data collectively suggest that the Ci is sensed through the second messenger cAMP releasing membrane-bound SyCRP1 into cytoplasm under sufficient CO2 conditions. Hence, SyCRP1 is a possible regulator of carbon concentrating mechanism, and such a regulation might be mediated via sensing Ci levels through cAMP in Synechocystis.
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Affiliation(s)
- Lingaswamy Bantu
- From the Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Suraj Chauhan
- From the Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Afshan Srikumar
- From the Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Yoshihisa Hirakawa
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba 305-8572, Japan
| | - Iwane Suzuki
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba 305-8572, Japan
| | - Martin Hagemann
- Plant Physiology Department, Institute of Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Jogadhenu S S Prakash
- From the Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
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4
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Oeser S, Wallner T, Schuergers N, Bučinská L, Sivabalasarma S, Bähre H, Albers SV, Wilde A. Minor pilins are involved in motility and natural competence in the cyanobacterium Synechocystis sp. PCC 6803. Mol Microbiol 2021; 116:743-765. [PMID: 34115422 DOI: 10.1111/mmi.14768] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 06/04/2021] [Accepted: 06/05/2021] [Indexed: 11/28/2022]
Abstract
Cyanobacteria synthesize type IV pili, which are known to be essential for motility, adhesion and natural competence. They consist of long flexible fibers that are primarily composed of the major pilin PilA1 in Synechocystis sp. PCC 6803. In addition, Synechocystis encodes less abundant pilin-like proteins, which are known as minor pilins. In this study, we show that the minor pilin PilA5 is essential for natural transformation but is dispensable for motility and flocculation. In contrast, a set of minor pilins encoded by the pilA9-slr2019 transcriptional unit are necessary for motility but are dispensable for natural transformation. Neither pilA5-pilA6 nor pilA9-slr2019 are essential for pilus assembly as mutant strains showed type IV pili on the cell surface. Three further gene products with similarity to PilX-like minor pilins have a function in flocculation of Synechocystis. The results of our study indicate that different minor pilins facilitate distinct pilus functions. Further, our microarray analysis demonstrated that the transcription levels of the minor pilin genes change in response to surface contact. A total of 122 genes were determined to have altered transcription between planktonic and surface growth, including several plasmid genes which are involved exopolysaccharide synthesis and the formation of bloom-like aggregates.
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Affiliation(s)
- Sabrina Oeser
- Molecular Genetics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Thomas Wallner
- Molecular Genetics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Nils Schuergers
- Molecular Genetics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Lenka Bučinská
- Centre Algatech, Institute of Microbiology of the Czech Academy of Sciences, Trebon, Czech Republic
| | - Shamphavi Sivabalasarma
- Molecular Biology of Archaea, Institute of Biology II, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Heike Bähre
- Research Core Unit Metabolomics, Medical School Hannover, Hannover, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology II, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Annegret Wilde
- Molecular Genetics, Institute of Biology III, University of Freiburg, Freiburg, Germany
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Conradi FD, Mullineaux CW, Wilde A. The Role of the Cyanobacterial Type IV Pilus Machinery in Finding and Maintaining a Favourable Environment. Life (Basel) 2020; 10:life10110252. [PMID: 33114175 PMCID: PMC7690835 DOI: 10.3390/life10110252] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/18/2020] [Accepted: 10/21/2020] [Indexed: 12/11/2022] Open
Abstract
Type IV pili (T4P) are proteinaceous filaments found on the cell surface of many prokaryotic organisms and convey twitching motility through their extension/retraction cycles, moving cells across surfaces. In cyanobacteria, twitching motility is the sole mode of motility properly characterised to date and is the means by which cells perform phototaxis, the movement towards and away from directional light sources. The wavelength and intensity of the light source determine the direction of movement and, sometimes in concert with nutrient conditions, act as signals for some cyanobacteria to form mucoid multicellular assemblages. Formation of such aggregates or flocs represents an acclimation strategy to unfavourable environmental conditions and stresses, such as harmful light conditions or predation. T4P are also involved in natural transformation by exogenous DNA, secretion processes, and in cellular adaptation and survival strategies, further cementing the role of cell surface appendages. In this way, cyanobacteria are finely tuned by external stimuli to either escape unfavourable environmental conditions via phototaxis, exchange genetic material, and to modify their surroundings to fit their needs by forming multicellular assemblies.
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Affiliation(s)
- Fabian D. Conradi
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (F.D.C.); (C.W.M.)
| | - Conrad W. Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK; (F.D.C.); (C.W.M.)
| | - Annegret Wilde
- Institute of Biology III, University of Freiburg, Schänzlestr. 1, 79104 Freiburg; Germany
- Correspondence:
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6
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Wallner T, Pedroza L, Voigt K, Kaever V, Wilde A. The cyanobacterial phytochrome 2 regulates the expression of motility-related genes through the second messenger cyclic di-GMP. Photochem Photobiol Sci 2020; 19:631-643. [PMID: 32255440 DOI: 10.1039/c9pp00489k] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The cyanobacterial phytochrome Cph2 is a light-dependent diguanylate cyclase of the cyanobacterium Synechocystis 6803. Under blue light, Cph2-dependent increase in the cellular c-di-GMP concentration leads to inhibition of surface motility and enhanced flocculation of cells in liquid culture. However, the targets of second messenger signalling in this cyanobacterium and its mechanism of action remained unclear. Here, we determined the cellular concentrations of cAMP and c-di-GMP in wild-type and Δcph2 cells after exposure to blue and green light. Inactivation of cph2 completely abolished the blue-light dependent increase in c-di-GMP content. Therefore, a microarray analysis with blue-light grown wild-type and Δcph2 mutant cells was used to identify c-di-GMP dependent alterations in transcript accumulation. The increase in the c-di-GMP content alters expression of genes encoding putative cell appendages, minor pilins and components of chemotaxis systems. The mRNA encoding the minor pilins pilA5-pilA6 was negatively affected by high c-di-GMP content under blue light, whereas the minor pilin encoding operon pilA9-slr2019 accumulates under these conditions, suggesting opposing functions of the respective gene sets. Artificial overproduction of c-di-GMP leads to similar changes in minor pilin gene expression and supports previous findings that c-di-GMP is important for flocculation via the function of minor pilins. Mutational and gene expression analysis further suggest that SyCRP2, a CRP-like transcription factor, is involved in regulation of minor pilin and putative chaperone usher pili gene expression.
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Affiliation(s)
- Thomas Wallner
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany.
| | - Laura Pedroza
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Karsten Voigt
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Volkhard Kaever
- Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Annegret Wilde
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
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7
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Chen Z, Li X, Tan X, Zhang Y, Wang B. Recent Advances in Biological Functions of Thick Pili in the Cyanobacterium Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2020; 11:241. [PMID: 32210999 PMCID: PMC7076178 DOI: 10.3389/fpls.2020.00241] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 02/17/2020] [Indexed: 05/05/2023]
Abstract
Cyanobacteria have evolved various strategies to sense and adapt to biotic and abiotic stresses including active movement. Motility in cyanobacteria utilizing the type IV pili (TFP) is useful to cope with changing environmental conditions. The model cyanobacterium Synechocystis sp. PCC 6803 (hereafter named Synechocystis) exhibits motility via TFP called thick pili, and uses it to seek out favorable light/nutrition or escape from unfavorable conditions. Recently, a number of studies on Synechocystis thick pili have been undertaken. Molecular approaches support the role of the pilin in motility, cell adhesion, metal utilization, and natural competence in Synechocystis. This review summarizes the most recent studies on the function of thick pili as well as their formation and regulation in this cyanobacterium.
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Affiliation(s)
- Zhuo Chen
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Xitong Li
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Xiaoming Tan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Yan Zhang
- Biotechnology Research Center, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Baoshan Wang
- Shandong Provincial Key Laboratory of Plant Stress, College of Life Sciences, Shandong Normal University, Jinan, China
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8
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Sycrp2 Is Essential for Twitching Motility in the Cyanobacterium Synechocystis sp. Strain PCC 6803. J Bacteriol 2018; 200:JB.00436-18. [PMID: 30104238 DOI: 10.1128/jb.00436-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 08/10/2018] [Indexed: 01/13/2023] Open
Abstract
Two cAMP receptor proteins (CRPs), Sycrp1 (encoded by sll1371) and Sycrp2 (encoded by sll1924), exist in the cyanobacterium Synechocystis sp. strain PCC 6803. Previous studies have demonstrated that Sycrp1 has binding affinity for cAMP and is involved in motility by regulating the formation of pili. However, the function of Sycrp2 remains unknown. Here, we report that sycrp2 disruption results in the loss of motility of Synechocystis sp. PCC 6803, and that the phenotype can be recovered by reintroducing the sycrp2 gene into the genome of sycrp2-disrupted mutants. Electron microscopy showed that the sycrp2-disrupted mutant lost the pilus apparatus on the cell surface, resulting in a lack of cell motility. Furthermore, the transcript level of the pilA9-pilA11 operon (essential for cell motility and regulated by the cAMP receptor protein Sycrp1) was markedly decreased in sycrp2-disrupted mutants compared with the wild-type strain. Moreover, yeast two-hybrid analysis and a pulldown assay demonstrated that Sycrp2 interacted with Sycrp1 to form a heterodimer and that Sycrp1 and Sycrp2 interacted with themselves to form homodimers. Gel mobility shift assays revealed that Sycrp1 specifically binds to the upstream region of pilA9 Together, these findings indicate that in Synechocystis sp. PCC 6803, Sycrp2 regulates the formation of pili and cell motility by interacting with Sycrp1.IMPORTANCE cAMP receptor proteins (CRPs) are widely distributed in cyanobacteria and play important roles in regulating gene expression. Although many cyanobacterial species have two cAMP receptor-like proteins, the functional links between them are unknown. Here, we found that Sycrp2 in the cyanobacterium Synechocystis sp. strain PCC 6803 is essential for twitching motility and that it interacts with Sycrp1, a known cAMP receptor protein involved with twitching motility. Our findings indicate that the two cAMP receptor-like proteins in cyanobacteria do not have functional redundancy but rather work together.
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9
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Hu J, Zhan J, Chen H, He C, Cang H, Wang Q. The Small Regulatory Antisense RNA PilR Affects Pilus Formation and Cell Motility by Negatively Regulating pilA11 in Synechocystis sp. PCC 6803. Front Microbiol 2018; 9:786. [PMID: 29740417 PMCID: PMC5924778 DOI: 10.3389/fmicb.2018.00786] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 04/06/2018] [Indexed: 01/19/2023] Open
Abstract
Pili are found on the surface of many bacteria and play important roles in cell motility, pathogenesis, biofilm formation, and sensing and reacting to environmental changes. Cell motility in the model cyanobacterium Synechocystis sp. PCC 6803 relies on expression of the putative pilA9-pilA10-pilA11-slr2018 operon. In this study, we identified the antisense RNA PilR encoded in the noncoding strand of the prepilin-encoding gene pilA11. Analysis of overexpressor [PilR(+)] and suppressor [PilR(-)] mutant strains revealed that PilR is a direct negative regulator of PilA11 protein. Although overexpression of PilR did not affect cell growth, it greatly reduced levels of pilA11 mRNA and protein and decreased both the thickness and number of pili, resulting in limited cell motility and small, distinct colonies. Suppression of PilR had the opposite effect. A hypothetical model on the regulation of pilA9-pilA10-pilA11-slr2018 operon expression by PilR was proposed. These results add a layer of complexity to the mechanisms controlling pilA11 gene expression and cell motility, and provide novel insights into how sRNA and the intergenic region secondary structures can work together to discoordinatly regulate target gene in an operon in cyanobacterium.
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Affiliation(s)
- Jinlu Hu
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Jiao Zhan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Hui Chen
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology of China, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Chenliu He
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Huaixing Cang
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, China
| | - Qiang Wang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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10
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Kizawa A, Kawahara A, Takimura Y, Nishiyama Y, Hihara Y. RNA-seq Profiling Reveals Novel Target Genes of LexA in the Cyanobacterium Synechocystis sp. PCC 6803. Front Microbiol 2016; 7:193. [PMID: 26925056 PMCID: PMC4759255 DOI: 10.3389/fmicb.2016.00193] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 02/04/2016] [Indexed: 11/13/2022] Open
Abstract
LexA is a well-established transcriptional repressor of SOS genes induced by DNA damage in Escherichia coli and other bacterial species. However, LexA in the cyanobacterium Synechocystis sp. PCC 6803 has been suggested not to be involved in SOS response. In this study, we performed RNA-seq analysis of the wild-type strain and the lexA-disrupted mutant to obtain the comprehensive view of LexA-regulated genes in Synechocystis. Disruption of lexA positively or negatively affected expression of genes related to various cellular functions such as phototactic motility, accumulation of the major compatible solute glucosylglycerol and subunits of bidirectional hydrogenase, photosystem I, and phycobilisome complexes. We also observed increase in the expression level of genes related to iron and manganese uptake in the mutant at the later stage of cultivation. However, none of the genes related to DNA metabolism were affected by disruption of lexA. DNA gel mobility shift assay using the recombinant LexA protein suggested that LexA binds to the upstream region of pilA7, pilA9, ggpS, and slr1670 to directly regulate their expression, but changes in the expression level of photosystem I genes by disruption of lexA is likely a secondary effect.
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Affiliation(s)
- Ayumi Kizawa
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University Saitama, Japan
| | - Akihito Kawahara
- Biological Science Laboratories, KAO Corporation Wakayama, Japan
| | - Yasushi Takimura
- Biological Science Laboratories, KAO Corporation Wakayama, Japan
| | - Yoshitaka Nishiyama
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University Saitama, Japan
| | - Yukako Hihara
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama UniversitySaitama, Japan; Core Research of Evolutional Science and Technology, Japan Science and Technology AgencySaitama, Japan
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11
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Chau RMW, Ursell T, Wang S, Huang KC, Bhaya D. Maintenance of motility bias during cyanobacterial phototaxis. Biophys J 2016; 108:1623-1632. [PMID: 25863054 DOI: 10.1016/j.bpj.2015.01.042] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 12/23/2014] [Accepted: 01/02/2015] [Indexed: 11/20/2022] Open
Abstract
Signal transduction in bacteria is complex, ranging across scales from molecular signal detectors and effectors to cellular and community responses to stimuli. The unicellular, photosynthetic cyanobacterium Synechocystis sp. PCC6803 transduces a light stimulus into directional movement known as phototaxis. This response occurs via a biased random walk toward or away from a directional light source, which is sensed by intracellular photoreceptors and mediated by Type IV pili. It is unknown how quickly cells can respond to changes in the presence or directionality of light, or how photoreceptors affect single-cell motility behavior. In this study, we use time-lapse microscopy coupled with quantitative single-cell tracking to investigate the timescale of the cellular response to various light conditions and to characterize the contribution of the photoreceptor TaxD1 (PixJ1) to phototaxis. We first demonstrate that a community of cells exhibits both spatial and population heterogeneity in its phototactic response. We then show that individual cells respond within minutes to changes in light conditions, and that movement directionality is conferred only by the current light directionality, rather than by a long-term memory of previous conditions. Our measurements indicate that motility bias likely results from the polarization of pilus activity, yielding variable levels of movement in different directions. Experiments with a photoreceptor (taxD1) mutant suggest a supplementary role of TaxD1 in enhancing movement directionality, in addition to its previously identified role in promoting positive phototaxis. Motivated by the behavior of the taxD1 mutant, we demonstrate using a reaction-diffusion model that diffusion anisotropy is sufficient to produce the observed changes in the pattern of collective motility. Taken together, our results establish that single-cell tracking can be used to determine the factors that affect motility bias, which can then be coupled with biophysical simulations to connect changes in motility behaviors at the cellular scale with group dynamics.
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Affiliation(s)
| | - Tristan Ursell
- Department of Bioengineering, Stanford University, Stanford, California
| | - Shuo Wang
- Department of Bioengineering, Stanford University, Stanford, California
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, California; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California.
| | - Devaki Bhaya
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California.
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12
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Sharma R, Zaveri A, Gopalakrishnapai J, Srinath T, Thiruneelakantan S, Varshney U, Visweswariah SS. Paralogous cAMP receptor proteins in Mycobacterium smegmatis show biochemical and functional divergence. Biochemistry 2014; 53:7765-76. [PMID: 25434596 DOI: 10.1021/bi500924v] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The cyclic AMP receptor protein (CRP) family of transcription factors consists of global regulators of bacterial gene expression. Here, we identify two paralogous CRPs in the genome of Mycobacterium smegmatis that have 78% identical sequences and characterize them biochemically and functionally. The two proteins (MSMEG_0539 and MSMEG_6189) show differences in cAMP binding affinity, trypsin sensitivity, and binding to a CRP site that we have identified upstream of the msmeg_3781 gene. MSMEG_6189 binds to the CRP site readily in the absence of cAMP, while MSMEG_0539 binds in the presence of cAMP, albeit weakly. msmeg_6189 appears to be an essential gene, while the Δmsmeg_0539 strain was readily obtained. Using promoter-reporter constructs, we show that msmeg_3781 is regulated by CRP binding, and its transcription is repressed by MSMEG_6189. Our results are the first to characterize two paralogous and functional CRPs in a single bacterial genome. This gene duplication event has subsequently led to the evolution of two proteins whose biochemical differences translate to differential gene regulation, thus catering to the specific needs of the organism.
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Affiliation(s)
- Ritu Sharma
- Department of Molecular Reproduction, Development and Genetics and ‡Department of Microbiology and Cell Biology, Indian Institute of Science , Bangalore 560012, India
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Survival strategies in the aquatic and terrestrial world: the impact of second messengers on cyanobacterial processes. Life (Basel) 2014; 4:745-69. [PMID: 25411927 PMCID: PMC4284465 DOI: 10.3390/life4040745] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/31/2014] [Accepted: 11/05/2014] [Indexed: 12/15/2022] Open
Abstract
Second messengers are intracellular substances regulated by specific external stimuli globally known as first messengers. Cells rely on second messengers to generate rapid responses to environmental changes and the importance of their roles is becoming increasingly realized in cellular signaling research. Cyanobacteria are photooxygenic bacteria that inhabit most of Earth's environments. The ability of cyanobacteria to survive in ecologically diverse habitats is due to their capacity to adapt and respond to environmental changes. This article reviews known second messenger-controlled physiological processes in cyanobacteria. Second messengers used in these systems include the element calcium (Ca2+), nucleotide-based guanosine tetraphosphate or pentaphosphate (ppGpp or pppGpp, represented as (p)ppGpp), cyclic adenosine 3',5'-monophosphate (cAMP), cyclic dimeric GMP (c-di-GMP), cyclic guanosine 3',5'-monophosphate (cGMP), and cyclic dimeric AMP (c-di-AMP), and the gaseous nitric oxide (NO). The discussion focuses on processes central to cyanobacteria, such as nitrogen fixation, light perception, photosynthesis-related processes, and gliding motility. In addition, we address future research trajectories needed to better understand the signaling networks and cross talk in the signaling pathways of these molecules in cyanobacteria. Second messengers have significant potential to be adapted as technological tools and we highlight possible novel and practical applications based on our understanding of these molecules and the signaling networks that they control.
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Giner-Lamia J, López-Maury L, Florencio FJ. Global transcriptional profiles of the copper responses in the cyanobacterium Synechocystis sp. PCC 6803. PLoS One 2014; 9:e108912. [PMID: 25268225 PMCID: PMC4182526 DOI: 10.1371/journal.pone.0108912] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 08/27/2014] [Indexed: 12/22/2022] Open
Abstract
Copper is an essential element involved in fundamental processes like respiration and photosynthesis. However, it becomes toxic at high concentration, which has forced organisms to control its cellular concentration. We have recently described a copper resistance system in the cyanobacterium Synechocystis sp. PCC 6803, which is mediated by the two-component system, CopRS, a RND metal transport system, CopBAC and a protein of unknown function, CopM. Here, we report the transcriptional responses to copper additions at non-toxic (0.3 µM) and toxic concentrations (3 µM) in the wild type and in the copper sensitive copR mutant strain. While 0.3 µM copper slightly stimulated metabolism and promoted the exchange between cytochrome c6 and plastocyanin as soluble electron carriers, the addition of 3 µM copper catalyzed the formation of ROS, led to a general stress response and induced expression of Fe-S cluster biogenesis genes. According to this, a double mutant strain copRsufR, which expresses constitutively the sufBCDS operon, tolerated higher copper concentration than the copR mutant strain, suggesting that Fe-S clusters are direct targets of copper toxicity in Synechocystis. In addition we have also demonstrated that InrS, a nickel binding transcriptional repressor that belong to the CsoR family of transcriptional factor, was involved in heavy metal homeostasis, including copper, in Synechocystis. Finally, global gene expression analysis of the copR mutant strain suggested that CopRS only controls the expression of copMRS and copBAC operons in response to copper.
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Affiliation(s)
- Joaquin Giner-Lamia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
| | - Luis López-Maury
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
- * E-mail: (LLM); (FJF)
| | - Francisco J. Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Sevilla, Spain
- * E-mail: (LLM); (FJF)
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Schuergers N, Ruppert U, Watanabe S, Nürnberg DJ, Lochnit G, Dienst D, Mullineaux CW, Wilde A. Binding of the RNA chaperone Hfq to the type IV pilus base is crucial for its function in Synechocystis sp. PCC 6803. Mol Microbiol 2014; 92:840-52. [PMID: 24684190 DOI: 10.1111/mmi.12595] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2014] [Indexed: 12/17/2022]
Abstract
The bacterial RNA-binding protein Hfq functions in post-transcriptional regulation of gene expression. There is evidence in a range of bacteria for specific subcellular localization of Hfq; however, the mechanism and role of Hfq localization remain unclear. Cyanobacteria harbour a subfamily of Hfq that is structurally conserved but exhibits divergent RNA binding sites. Mutational analysis in the cyanobacterium Synechocystis sp. PCC 6803 revealed that several conserved amino acids on the proximal side of the Hfq hexamer are crucial not only for Hfq-dependent RNA accumulation but also for phototaxis, the latter of which depends on type IV pili. Co-immunoprecipitation and yeast two-hybrid analysis show that the secretion ATPase PilB1 (a component of the type IV pilus base) is an interaction partner of Hfq. Fluorescence microscopy revealed that Hfq is localized to the cytoplasmic membrane in a PilB1-dependent manner. Concomitantly, Hfq-dependent RNA accumulation is abrogated in a ΔpilB1 mutant, indicating that localization to the pilus base via interaction with PilB1 is essential for Hfq function in cyanobacteria.
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Affiliation(s)
- Nils Schuergers
- Molekulare Genetik, Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, Freiburg, D-79104, Germany
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Vass IZ, Kós PB, Knoppová J, Komenda J, Vass I. The cry-DASH cryptochrome encoded by the sll1629 gene in the cyanobacterium Synechocystis PCC 6803 is required for Photosystem II repair. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2014; 130:318-26. [DOI: 10.1016/j.jphotobiol.2013.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/26/2013] [Accepted: 12/09/2013] [Indexed: 12/16/2022]
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Abstract
Ultraviolet (UV) radiation can cause stresses or act as a photoregulatory signal depending on its wavelengths and fluence rates. Although the most harmful effects of UV on living cells are generally attributed to UV-B radiation, UV-A radiation can also affect many aspects of cellular processes. In cyanobacteria, most studies have concentrated on the damaging effect of UV and defense mechanisms to withstand UV stress. However, little is known about the activation mechanism of signaling components or their pathways which are implicated in the process following UV irradiation. Motile cyanobacteria use a very precise negative phototaxis signaling system to move away from high levels of solar radiation, which is an effective escape mechanism to avoid the detrimental effects of UV radiation. Recently, two different UV-A-induced signaling systems for regulating cyanobacterial phototaxis were characterized at the photophysiological and molecular levels. Here, we review the current understanding of the UV-A mediated signaling pathways in the context of the UV-A perception mechanism, early signaling components, and negative phototactic responses. In addition, increasing evidences supporting a role of pterins in response to UV radiation are discussed. We outline the effect of UV-induced cell damage, associated signaling molecules, and programmed cell death under UV-mediated oxidative stress.
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Yoshimura H, Kaneko Y, Ehira S, Yoshihara S, Ikeuchi M, Ohmori M. CccS and CccP are involved in construction of cell surface components in the cyanobacterium Synechocystis sp. strain PCC 6803. PLANT & CELL PHYSIOLOGY 2010; 51:1163-72. [PMID: 20538620 DOI: 10.1093/pcp/pcq081] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We have previously identified two target genes (slr1667 and slr1668) for transcriptional regulation by a cAMP receptor protein, SYCRP1, in a cAMP-dependent manner. For this study we investigated the localizations of products of slr1667 and slr1668 (designated cccS and cccP, respectively) biochemically and immunocytochemically, and examined the phenotypes of their disruptants. CccS protein was detected in the culture medium and the acid-soluble fraction containing proteins derived from outside the outer membrane. Disruptants of cccS and cccP showed a more or less similar pleiotropic phenotype. Several proteins secreted into the culture medium or retained on the outside of the outer membrane were greatly reduced in both disruptants compared with the wild type. Electron microscopy revealed that the cccS disruptant lacked the thick pili responsible for motility and that the cccP disruptant had almost no discernible thick pili on its cell surface. Both disruptants largely secreted far greater amounts of yellow pigments into the culture medium than did the wild type. Furthermore, the disruptions reduced the amount of UV-absorbing compound(s) extractable from the exopolysaccharide layer. These results suggest that the cccS and cccP genes are involved in the construction of cell surface components in Synechocystis sp. strain PCC 6803.
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Affiliation(s)
- Hidehisa Yoshimura
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo. 153-8902 Japan.
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Gunnelius L, Tuominen I, Rantamäki S, Pollari M, Ruotsalainen V, Tyystjärvi E, Tyystjärvi T. SigC sigma factor is involved in acclimation to low inorganic carbon at high temperature in Synechocystis sp. PCC 6803. MICROBIOLOGY-SGM 2009; 156:220-229. [PMID: 19729407 DOI: 10.1099/mic.0.032565-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Inactivation of the sigC gene (sll0184), encoding the group 2 sigma factor SigC, leads to a heat-sensitive phenotype of Synechocystis sp. PCC 6803. Cells of the DeltasigC strain grew poorly at 43 degrees C at pH 7.5 under ambient CO(2) conditions. Addition of inorganic carbon in the form of 3 % CO(2) or use of an alkaline growth medium (pH 8.3) restored the growth of the DeltasigC strain at 43 degrees C. These treatments compensate for the low concentration of inorganic carbon at high temperature. However, addition of organic carbon as glucose, pyruvate, succinate or 2-oxoglutarate did not restore growth of the DeltasigC strain at 43 degrees C. In the control strain, the amount of the SigC factor diminished after prolonged incubation at 43 degrees C if the pH of the growth medium was 7.5 or 6.7. Under alkaline conditions, the amount of the SigC factor remained constant at 43 degrees C and cells of the control strain grew better than at pH 7.5 or pH 6.7. The pH dependence of high-temperature growth was associated with changes in photosynthetic activity, indicating that the SigC factor is involved in adjustment of photosynthesis according to the amount of available inorganic carbon. Our results indicate that acclimation to low inorganic carbon is a part of acclimation to prolonged high temperature and that the SigC factor has a central role in this acclimation.
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Affiliation(s)
- Liisa Gunnelius
- Plant Physiology and Molecular Biology, Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Ilona Tuominen
- Plant Physiology and Molecular Biology, Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Susanne Rantamäki
- Plant Physiology and Molecular Biology, Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Maija Pollari
- Plant Physiology and Molecular Biology, Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Virpi Ruotsalainen
- Plant Physiology and Molecular Biology, Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Esa Tyystjärvi
- Plant Physiology and Molecular Biology, Department of Biology, University of Turku, FI-20014 Turku, Finland
| | - Taina Tyystjärvi
- Plant Physiology and Molecular Biology, Department of Biology, University of Turku, FI-20014 Turku, Finland
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Hedger J, Holmquist PC, Leigh KA, Saraff K, Pomykal C, Summers ML. Illumination stimulates cAMP receptor protein-dependent transcriptional activation from regulatory regions containing class I and class II promoter elements in Synechocystis sp. PCC 6803. MICROBIOLOGY-SGM 2009; 155:2994-3004. [PMID: 19542007 DOI: 10.1099/mic.0.028035-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The cAMP receptor protein (Crp) is a global transcriptional regulator that binds sequence-specific promoter elements when associated with cAMP. In the motile cyanobacterium Synechocystis sp. strain PCC 6803, intracellular cAMP increases when dark-adapted cells are illuminated. Previous work has established that Crp binds proposed Crp target sites upstream of slr1351 (murF), sll1874 (chlA(II)), sll1708 (narL), slr0442 and sll1268 in vitro, and that slr0442 is downregulated in a crp mutant during photoautotrophic growth. To identify additional Crp target genes in Synechocystis, 11 different Crp binding sites proposed during a previous computational survey were tested for in vitro sequence-specific binding and crp-dependent transcription. The results indicate that murF, chlA(II) and slr0442 can be added as 'target genes of Sycrp1' in Synechocystis. Promoter mapping of the targets revealed the same close association of RNA polymerase and Crp as that found in Escherichia coli class I and class II Crp-regulated promoters, thereby strongly suggesting similar mechanisms of transcriptional activation.
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Affiliation(s)
- Jennifer Hedger
- California State University Northridge, Department of Biology, 18111 Nordhoff St, Northridge, CA 91330, USA
| | - Peter C Holmquist
- California State University Northridge, Department of Biology, 18111 Nordhoff St, Northridge, CA 91330, USA
| | | | - Kumuda Saraff
- California State University Northridge, Department of Biology, 18111 Nordhoff St, Northridge, CA 91330, USA
| | - Christina Pomykal
- California State University Northridge, Department of Biology, 18111 Nordhoff St, Northridge, CA 91330, USA
| | - Michael L Summers
- California State University Northridge, Department of Biology, 18111 Nordhoff St, Northridge, CA 91330, USA
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21
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Xu M, Su Z. Computational prediction of cAMP receptor protein (CRP) binding sites in cyanobacterial genomes. BMC Genomics 2009; 10:23. [PMID: 19146659 PMCID: PMC2633013 DOI: 10.1186/1471-2164-10-23] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2008] [Accepted: 01/15/2009] [Indexed: 11/30/2022] Open
Abstract
Background Cyclic AMP receptor protein (CRP), also known as catabolite gene activator protein (CAP), is an important transcriptional regulator widely distributed in many bacteria. The biological processes under the regulation of CRP are highly diverse among different groups of bacterial species. Elucidation of CRP regulons in cyanobacteria will further our understanding of the physiology and ecology of this important group of microorganisms. Previously, CRP has been experimentally studied in only two cyanobacterial strains: Synechocystis sp. PCC 6803 and Anabaena sp. PCC 7120; therefore, a systematic genome-scale study of the potential CRP target genes and binding sites in cyanobacterial genomes is urgently needed. Results We have predicted and analyzed the CRP binding sites and regulons in 12 sequenced cyanobacterial genomes using a highly effective cis-regulatory binding site scanning algorithm. Our results show that cyanobacterial CRP binding sites are very similar to those in E. coli; however, the regulons are very different from that of E. coli. Furthermore, CRP regulons in different cyanobacterial species/ecotypes are also highly diversified, ranging from photosynthesis, carbon fixation and nitrogen assimilation, to chemotaxis and signal transduction. In addition, our prediction indicates that crp genes in modern cyanobacteria are likely inherited from a common ancestral gene in their last common ancestor, and have adapted various cellular functions in different environments, while some cyanobacteria lost their crp genes as well as CRP binding sites during the course of evolution. Conclusion The CRP regulons in cyanobacteria are highly diversified, probably as a result of divergent evolution to adapt to various ecological niches. Cyanobacterial CRPs may function as lineage-specific regulators participating in various cellular processes, and are important in some lineages. However, they are dispensable in some other lineages. The loss of CRPs in these species leads to the rapid loss of their binding sites in the genomes.
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Affiliation(s)
- Minli Xu
- Department of Bioinformatics and Genomics, Bioinformatics Research Center, the University of North Carolina at Charlotte, Charlotte, NC 28233, USA.
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22
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Abstract
Microorganisms have various mechanisms at their disposal to react to (changes in) their ambient light climate (i.e., intensity, color, direction, and degree of polarization). Of these, one of the best studied mechanisms is the process of phototaxis. This process can be described as a behavioral migration-response of an organism toward a change in illumination regime. In this chapter we discuss three of these migration responses, based on swimming, swarming, and twitching motility, respectively. Swimming motility has been studied using a wide range of techniques, usually microscopy based. We present a detailed description of the assays used to study phototaxis in liquid cultures of the phototrophic organisms Halobacterium salinarum, Halorhodospira halophila, and Rhodobacter sphaeroides and briefly describe the molecular basis of these responses. Swarming and twitching motility are processes taking place at the interface between a solid phase and a liquid or gas phase. Although assays to study these processes are relatively straightforward, they are accompanied by technical complications, which we describe. Furthermore, we discuss the molecular processes underlying these forms of motility in Rhodocista centenaria and Synechocystis PCC6803. Recently, it has become clear that also chemotrophic organisms contain photoreceptor proteins that allow them to respond to their ambient light climate. Surprisingly, light-modulated motility responses can also be observed in the chemotrophic organisms Escherichia coli and Acinetobacter calcoaceticus. In the light-modulated surface migration not only "che-like" signal transduction reactions may play a role, but in addition processes as modulation of gene expression and even intermediary metabolism.
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Affiliation(s)
- Wouter D Hoff
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA
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23
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Dienst D, Dühring U, Mollenkopf HJ, Vogel J, Golecki J, Hess WR, Wilde A. The cyanobacterial homologue of the RNA chaperone Hfq is essential for motility of Synechocystis sp. PCC 6803. MICROBIOLOGY-SGM 2008; 154:3134-3143. [PMID: 18832319 DOI: 10.1099/mic.0.2008/020222-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The ssr3341 locus was previously suggested to encode an orthologue of the RNA chaperone Hfq in the cyanobacterium Synechocystis sp. strain PCC 6803. Insertional inactivation of this gene resulted in a mutant that was not naturally transformable and exhibited a non-phototactic phenotype compared with the wild-type. The loss of motility was complemented by reintroduction of the wild-type gene, correlated with the re-establishment of type IV pili on the cell surface. Microarray analyses revealed a small set of genes with drastically reduced transcript levels in the knockout mutant compared with the wild-type cells. Among the most strongly affected genes, slr1667, slr1668, slr2015, slr2016 and slr2018 stood out, as they belong to two operons that had previously been shown to be involved in motility, controlled by the cAMP receptor protein SYCRP1. This suggests a link between cAMP signalling, motility and possibly the involvement of RNA-based regulation. This is believed to be the first report demonstrating a functional role of an Hfq orthologue in cyanobacteria, establishing a new factor in the control of motility.
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Affiliation(s)
- Dennis Dienst
- Humboldt-University Berlin, Institute of Biology, Chausseestr. 117, 10115 Berlin, Germany
| | - Ulf Dühring
- Humboldt-University Berlin, Institute of Biology, Chausseestr. 117, 10115 Berlin, Germany
| | | | - Jörg Vogel
- Max Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
| | - Jochen Golecki
- University of Freiburg, Faculty of Biology, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Wolfgang R Hess
- University of Freiburg, Faculty of Biology, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Annegret Wilde
- Justus-Liebig University Giessen, Institute of Microbiology and Molecular Biology, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.,Humboldt-University Berlin, Institute of Biology, Chausseestr. 117, 10115 Berlin, Germany
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Omagari K, Yoshimura H, Suzuki T, Takano M, Ohmori M, Sarai A. ΔG-based prediction and experimental confirmation of SYCRP1-binding sites on the Synechocystis genome. FEBS J 2008; 275:4786-95. [DOI: 10.1111/j.1742-4658.2008.06618.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
This work studies two mathematical models for describing the motion of phototactic bacteria, i.e., bacteria that move toward light. Based on experimental observations, we conjecture that the motion of the colony toward light depends on certain group dynamics. These group dynamics are hypothesized to be coordinated through an individual property of each bacterium, which we refer to as excitation. The excitation of each individual bacterium is assumed to change based on the excitation of the neighboring bacteria. Under these assumptions, we propose a (discrete) cellular automaton model and derive an analogous stochastic model for describing the evolution in time of the location of bacteria, the excitation of individual bacteria, and a surface memory effect. We provide simulation results and discuss in detail the role of the various model parameters in controlling the emerging dynamics.
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26
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Suzuki T, Yoshimura H, Ehira S, Ikeuchi M, Ohmori M. AnCrpA, a cAMP receptor protein, regulates nif-related gene expression in the cyanobacterium Anabaena sp. strain PCC 7120 grown with nitrate. FEBS Lett 2006; 581:21-8. [PMID: 17173896 DOI: 10.1016/j.febslet.2006.11.070] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 11/08/2006] [Accepted: 11/23/2006] [Indexed: 10/23/2022]
Abstract
Target genes for a cAMP receptor protein, AnCrpA, were screened using an Anabaena oligonucleotide microarray and real-time quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis. Several gene expressions, including some involved in nitrogen fixation, were downregulated in the ancrpA disruptant when cells were grown with nitrate. Electrophoretic mobility shift assays (EMSAs) revealed that AnCrpA bound to the 5' upstream region of nifB, all1439, hesA, all5347, hglE and coxBII in the presence of cAMP, and all of them are related with nitrogen fixation. A possible AnCrpA-binding site in the 5' upstream region of nifB was predicted using hidden Markov model (HMM) software based on the result of in vitro selection of AnCrpA-binding sequences, and the binding was confirmed by EMSA. Thus, AnCrpA regulates the expressions of gene clusters related to nitrogen fixation in the presence of nitrate.
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Affiliation(s)
- Takayuki Suzuki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan
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27
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Bhaya D, Nakasugi K, Fazeli F, Burriesci MS. Phototaxis and impaired motility in adenylyl cyclase and cyclase receptor protein mutants of Synechocystis sp. strain PCC 6803. J Bacteriol 2006; 188:7306-10. [PMID: 17015670 PMCID: PMC1636242 DOI: 10.1128/jb.00573-06] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have carefully characterized and reexamined the motility and phototactic responses of Synechocystis sp. adenylyl cyclase (Cya1) and catabolite activator protein (SYCRP1) mutants to different light regimens, glucose, 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and cyclic AMP. We find that contrary to earlier reports, cya1 and sycrp1 mutants are motile and phototactic but are impaired in one particular phase of phototaxis in comparison with wild-type Synechocystis sp.
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Affiliation(s)
- Devaki Bhaya
- Carnegie Institution, 260 Panama Street, Stanford, CA 94305, USA.
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28
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Masuda S, Ono TA. Adenylyl cyclase activity of Cya1 from the cyanobacterium Synechocystis sp. strain PCC 6803 is inhibited by bicarbonate. J Bacteriol 2005; 187:5032-5. [PMID: 15995223 PMCID: PMC1169521 DOI: 10.1128/jb.187.14.5032-5035.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bicarbonate stimulates the activities of several class III adenylyl cyclases studied to date. However, we show here that bicarbonate decreased V(max) and substrate affinity in Cya1, a major adenylyl cyclase in the cyanobacterium Synechocystis sp. strain PCC 6803. This indicates that manifestation of the bicarbonate responsiveness is specifically modulated in Cya1.
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Affiliation(s)
- Shinji Masuda
- Laboratory for Photo-Biology, RIKEN Photodynamics Research Center, The Institute of Physical and Chemical Research, Aramaki, Aoba, Sendai, Japan.
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29
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Cadoret JC, Rousseau B, Perewoska I, Sicora C, Cheregi O, Vass I, Houmard J. Cyclic nucleotides, the photosynthetic apparatus and response to a UV-B stress in the Cyanobacterium Synechocystis sp. PCC 6803. J Biol Chem 2005; 280:33935-44. [PMID: 16096278 DOI: 10.1074/jbc.m503153200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cyclic nucleotides cAMP and cGMP are ubiquitous signaling molecules that mediate many adaptative responses in eukaryotic cells. Cyanobacteria present the peculiarity among the prokaryotes of having the two types of cyclic nucleotide. Cellular homeostasis requires both cyclases (adenylyl/guanylyl, for their synthesis) and phosphodiesterases (for their degradation). Fully segregated null mutants have been obtained for the two genes, sll1624 and slr2100, which encode putative cNMP phosphodiesterases. We present physiological evidence that the Synechocystis PCC 6803 open reading frame slr2100 could be a cGMP phosphodiesterase. In addition, we show that Slr2100, but not Sll1624, is required for the adaptation of the cells to a UV-B stress. UV-B radiation has deleterious effects for photosynthetic organisms, in particular on the photosystem II, through damaging the protein structure of the reaction center. Using biophysical and biochemical approaches, it was found that Slr2100 is involved in the signal transduction events which permit the repair of the UV-B-damaged photosystem II. This was confirmed by quantitative reverse transcriptase-PCR analyses. Altogether, the data point to an important role for cGMP in signal transduction and photoacclimation processes during a UV-B stress.
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Affiliation(s)
- Jean-Charles Cadoret
- Organismes Photosynthétiques et Environnement, CNRS FRE 2433, Département de Biologie, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France
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30
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Masuda S, Ono TA. Biochemical characterization of the major adenylyl cyclase, Cya1, in the cyanobacterium Synechocystis sp. PCC 6803. FEBS Lett 2005; 577:255-8. [PMID: 15527795 DOI: 10.1016/j.febslet.2004.09.086] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Revised: 09/26/2004] [Accepted: 09/27/2004] [Indexed: 10/26/2022]
Abstract
We report herein the biochemical properties of an adenylyl cyclase, Cya1, from the cyanobacterium Synechocystis sp. PCC 6803. Heterologously expressed Cya1 catalyzed cyclic AMP formation with a Km for ATP of approximately 2.2 microM at pH 7.5. Although cellular Cya1 activity is increased by blue light illumination [Terauchi and Ohmori, Mol. Microbiol. 52 (2004) 303], purified Cya1 did not contain any chromophores, and the activity was light-insensitive. This suggests that an unknown blue light-responsive factor interacts with the N-terminal regulatory domain of Cya1 to control its adenylyl cyclase activity. Finally, our results show that the sensor of blue light using FAD (BLUF) protein, Slr1694, does not appear to be involved in the regulation of Cya1-mediated cAMP signal transduction in this bacterium.
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Affiliation(s)
- Shinji Masuda
- Laboratory for Photo-Biology (1), RIKEN Photodynamics Research Center, The Institute of Physical and Chemical Research, 519-1399 Aramaki, Aoba, Sendai 980-0845, Japan.
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Abstract
Many photosynthetic microorganisms have evolved the ability to sense light quality and/or quantity and can steer themselves into optimal conditions within the environment. Phototaxis and gliding motility in unicellular cyanobacteria require type IV pili, which are multifunctional cell surface appendages. Screens for cells exhibiting aberrant motility uncovered several non-motile mutants as well as some that had lost positive phototaxis (consequently, they were negatively phototactic). Several negatively phototactic mutants mapped to the tax1 locus, which contains five chemotaxis-like genes. This locus includes a gene that encodes a putative photoreceptor (TaxD1) for positive phototaxis. A second chemotaxis-like cluster (tax3 locus) appears to be involved in pilus biogenesis. The biosynthesis and regulation of type IV pilus-based motility as well as the communication between the pilus motor and photosensory molecules appear to be complex and tightly regulated. Furthermore, the discovery that cyclic AMP and novel gene products are necessary for phototaxis/motility suggests that there might be additional levels of communication and signal processing.
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Affiliation(s)
- Devaki Bhaya
- Department of Plant Biology, Carnegie Institution of Washington, Stanford, CA 94305, USA.
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Suzuki T, Yoshimura H, Hisabori T, Ohmori M. Two cAMP receptor proteins with different biochemical properties in the filamentous cyanobacterium Anabaena sp. PCC 7120. FEBS Lett 2004; 571:154-60. [PMID: 15280034 DOI: 10.1016/j.febslet.2004.06.074] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Revised: 06/24/2004] [Accepted: 06/28/2004] [Indexed: 10/26/2022]
Abstract
Two open reading frames (ORFs), alr0295 and alr2325, are found to encode putative cAMP receptor proteins (CRPs) in the genome of the filamentous cyanobacterium Anabaena sp. PCC 7120. These ORFs were named cAMP receptor protein-like gene A in Anabaena sp. PCC 7120 (ancrpA) and cAMP receptor protein-like gene B in Anabaena sp. PCC 7120 (ancrpB), respectively, and those translated products were investigated. The equilibrium dialysis measurements revealed that AnCrpA bound with cAMP specifically, while AnCrpB bound with both cAMP and cGMP, though the affinity for cGMP was weak. The binding affinity for cAMP of AnCrpA showed the lowest dissociation constant, approximately 0.8 microM, among bacterial CRPs. A gel mobility shift assay elucidated that AnCrpA and AnCrpB formed a complex with the consensus DNA sequence in the presence of cAMP, although AnCrpB did not have ordinary DNA-binding motifs.
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Affiliation(s)
- Takayuki Suzuki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan
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Terauchi K, Ohmori M. Blue light stimulates cyanobacterial motility via a cAMP signal transduction system. Mol Microbiol 2004; 52:303-9. [PMID: 15049828 DOI: 10.1111/j.1365-2958.2003.03980.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The participation of cAMP in photosignal transduction in cyanobacteria was investigated. When cells of the cyanobacterium Synechocystis sp. PCC 6803 were exposed to light, cellular cAMP contents increased within a few minutes. Among incident monochromatic lights, blue light (450 nm) markedly increased cellular cAMP content, while red (630 nm) and far-red (720 nm) lights did not. Disruption of the cya1 gene encoding an adenylate cyclase caused the insensitivity of cellular cAMP level to blue light. Treatment of wild-type cells with the flavin antagonist phenylacetic acid inhibited this blue light effect. The motility of wild-type cells was enhanced by blue light, whereas that of cya1 mutant cells was not. Based on these results, we concluded that a blue light-cAMP signal transduction system stimulates the motility of Synechocystis sp. PCC 6803.
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Affiliation(s)
- Kazuki Terauchi
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan
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Poliquin K, Ershov YV, Cunningham FX, Woreta TT, Gantt RR, Gantt E. Inactivation of sll1556 in Synechocystis strain PCC 6803 impairs isoprenoid biosynthesis from pentose phosphate cycle substrates in vitro. J Bacteriol 2004; 186:4685-93. [PMID: 15231801 PMCID: PMC438581 DOI: 10.1128/jb.186.14.4685-4693.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2004] [Accepted: 04/19/2004] [Indexed: 11/20/2022] Open
Abstract
In cyanobacteria many compounds, including chlorophylls, carotenoids, and hopanoids, are synthesized from the isoprenoid precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate. Isoprenoid biosynthesis in extracts of the cyanobacterium Synechocystis strain PCC 6803 grown under photosynthetic conditions, stimulated by pentose phosphate cycle substrates, does not appear to require methylerythritol phosphate pathway intermediates. The sll1556 gene, distantly related to type 2 IPP isomerase genes, was disrupted by insertion of a Kanr cassette. The mutant was fully viable under photosynthetic conditions although impaired in the utilization of pentose phosphate cycle substrates. Compared to the parental strain the Deltasll1556 mutant (i) is deficient in isoprenoid biosynthesis in vitro with substrates including glyceraldehyde-3-phosphate, fructose-6-phosphate, and glucose-6-phosphate; (ii) has smaller cells (diameter ca. 13% less); (iii) has fewer thylakoids (ca. 30% less); and (iv) has a more extensive fibrous outer wall layer. Isoprenoid biosynthesis is restored with pentose phosphate cycle substrates plus the recombinant Sll1556 protein in the Deltasll1556 supernatant fraction. IPP isomerase activity could not be demonstrated for the purified Sll1556 protein under our in vitro conditions. The reduction of thylakoid area and the effect on outer wall layer components are consistent with an impairment of isoprenoid biosynthesis in the mutant, possibly via hopanoid biosynthesis. Our findings are consistent with an alternate metabolic shunt for biosynthesis of isoprenoids.
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Affiliation(s)
- Kelly Poliquin
- Department of Cell Biology and Molecular Genetics, Microbiology Building, Campus Dr., University of Maryland, College Park, MD 20742, USA
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