51
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Jin H, Lindblad P, Bhaya D. Building an Inducible T7 RNA Polymerase/T7 Promoter Circuit in Synechocystis sp. PCC6803. ACS Synth Biol 2019; 8:655-660. [PMID: 30935196 DOI: 10.1021/acssynbio.8b00515] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To develop tightly regulated orthogonal gene expression circuits in the photoautotrophic cyanobacterium Synechocystis sp. PCC6803 (Syn6803), we designed a circuit in which a native inducible promoter drives the expression of phage T7 RNA polymerase (T7RNAP). T7RNAP, in turn, specifically recognizes the T7 promoter that is designed to drive GFP expression. In Syn6803, this T7RNAP/T7promoter-GFP circuit produces high GFP fluorescence, which was further enhanced by using mutant T7 promoters. We also tested two orthogonal inducible promoters, Trc1O and L03, but these promoters drive T7RNAP to levels that are toxic in E. coli. Introduction of a protein degradation tag alleviated this problem. However, in Syn6803, these circuits did not function successfully. This highlights the underappreciated fact that similar circuits work with varying efficiencies in different chassis organisms. This lays the groundwork for developing new orthogonally controlled phage RNA polymerase-dependent expression systems in Syn6803.
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Affiliation(s)
- Haojie Jin
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, United States
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, SE 75120, Uppsala, Sweden
| | - Devaki Bhaya
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305, United States
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52
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Santos-Merino M, Singh AK, Ducat DC. New Applications of Synthetic Biology Tools for Cyanobacterial Metabolic Engineering. Front Bioeng Biotechnol 2019; 7:33. [PMID: 30873404 PMCID: PMC6400836 DOI: 10.3389/fbioe.2019.00033] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/05/2019] [Indexed: 01/25/2023] Open
Abstract
Cyanobacteria are promising microorganisms for sustainable biotechnologies, yet unlocking their potential requires radical re-engineering and application of cutting-edge synthetic biology techniques. In recent years, the available devices and strategies for modifying cyanobacteria have been increasing, including advances in the design of genetic promoters, ribosome binding sites, riboswitches, reporter proteins, modular vector systems, and markerless selection systems. Because of these new toolkits, cyanobacteria have been successfully engineered to express heterologous pathways for the production of a wide variety of valuable compounds. Cyanobacterial strains with the potential to be used in real-world applications will require the refinement of genetic circuits used to express the heterologous pathways and development of accurate models that predict how these pathways can be best integrated into the larger cellular metabolic network. Herein, we review advances that have been made to translate synthetic biology tools into cyanobacterial model organisms and summarize experimental and in silico strategies that have been employed to increase their bioproduction potential. Despite the advances in synthetic biology and metabolic engineering during the last years, it is clear that still further improvements are required if cyanobacteria are to be competitive with heterotrophic microorganisms for the bioproduction of added-value compounds.
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Affiliation(s)
- María Santos-Merino
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Amit K. Singh
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
| | - Daniel C. Ducat
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
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53
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Angeleri M, Muth-Pawlak D, Wilde A, Aro EM, Battchikova N. Global proteome response ofSynechocystis6803 to extreme copper environments applied to control the activity of the induciblepetJpromoter. J Appl Microbiol 2019; 126:826-841. [DOI: 10.1111/jam.14182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 12/18/2022]
Affiliation(s)
- M. Angeleri
- Molecular Plant Biology; Department of Biochemistry; University of Turku; Turku Finland
| | - D. Muth-Pawlak
- Molecular Plant Biology; Department of Biochemistry; University of Turku; Turku Finland
| | - A. Wilde
- Molecular Genetics of Prokaryotes; University of Freiburg; Freiburg Germany
| | - E.-M. Aro
- Molecular Plant Biology; Department of Biochemistry; University of Turku; Turku Finland
| | - N. Battchikova
- Molecular Plant Biology; Department of Biochemistry; University of Turku; Turku Finland
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54
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Wegelius A, Li X, Turco F, Stensjö K. Design and characterization of a synthetic minimal promoter for heterocyst-specific expression in filamentous cyanobacteria. PLoS One 2018; 13:e0203898. [PMID: 30204806 PMCID: PMC6133370 DOI: 10.1371/journal.pone.0203898] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 08/29/2018] [Indexed: 11/25/2022] Open
Abstract
Short and well defined promoters are essential for advancing cyanobacterial biotechnology. The heterocyst of Nostoc sp. is suggested as a microbial cell factory for oxygen sensitive catalysts, such as hydrogenases for hydrogen production, due to its microoxic environment. We identified and predicted promoter elements of possible significance through a consensus strategy using a pool of heterocyst-induced DIF+ promoters known from Anabaena sp. PCC 7120. To test if these conserved promoter elements were crucial for heterocyst-specific expression, promoter-yfp reporter constructs were designed. The characterization was accomplished by replacing, -35 and -10 regions and the upstream element, with well described elements from the trc promoter of Escherichia coli, which is also functional in Nostoc sp. From the in vivo spatial fluorescence of the different promoter-yfp reporters in Nostoc punctiforme ATCC 29133, we concluded that both the consensus -35 and extended -10 regions were important for heterocyst-specific expression. Further that the promoter strength could be improved by the addition of an upstream element. We designed a short synthetic promoter of 48 nucleotides, PsynDIF, including a consensus DIF1 sequence, a 17 base pair stretch of random nucleotides and an extended consensus -10 region, and thus generated the shortest promoter for heterocyst-specific expression to date.
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Affiliation(s)
- Adam Wegelius
- Department of Chemistry– Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Xin Li
- Department of Chemistry– Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Federico Turco
- Department of Chemistry– Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Karin Stensjö
- Department of Chemistry– Ångström Laboratory, Uppsala University, Uppsala, Sweden
- * E-mail:
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55
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Yunus IS, Jones PR. Photosynthesis-dependent biosynthesis of medium chain-length fatty acids and alcohols. Metab Eng 2018; 49:59-68. [DOI: 10.1016/j.ymben.2018.07.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/24/2018] [Accepted: 07/24/2018] [Indexed: 12/27/2022]
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56
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Synthetic Gene Regulation in Cyanobacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1080:317-355. [DOI: 10.1007/978-981-13-0854-3_13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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57
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Ferreira EA, Pacheco CC, Pinto F, Pereira J, Lamosa P, Oliveira P, Kirov B, Jaramillo A, Tamagnini P. Expanding the toolbox for Synechocystis sp. PCC 6803: validation of replicative vectors and characterization of a novel set of promoters. Synth Biol (Oxf) 2018; 3:ysy014. [PMID: 32995522 PMCID: PMC7445879 DOI: 10.1093/synbio/ysy014] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 07/27/2018] [Accepted: 07/30/2018] [Indexed: 11/14/2022] Open
Abstract
Cyanobacteria are promising 'low-cost' cell factories since they have minimal nutritional requirements, high metabolic plasticity and can use sunlight and CO2 as energy and carbon sources. The unicellular Synechocystis sp. PCC 6803, already considered the 'green' Escherichia coli, is the best studied cyanobacterium but to be used as an efficient and robust photoautotrophic chassis it requires a customized and well-characterized toolbox. In this context, we evaluated the possibility of using three self-replicative vectors from the Standard European Vector Architecture (SEVA) repository to transform Synechocystis. Our results demonstrated that the presence of the plasmid does not lead to an evident phenotype or hindered Synechocystis growth, being the vast majority of the cells able to retain the replicative plasmid even in the absence of selective pressure. In addition, a set of heterologous and redesigned promoters were characterized exhibiting a wide range of activities compared to the reference P rnpB , three of which could be efficiently repressed. As a proof-of-concept, from the expanded toolbox, one promoter was selected and assembled with the ggpS gene [encoding one of the proteins involved in the synthesis of the native compatible solute glucosylglycerol (GG)] and the synthetic device was introduced into Synechocystis using one of the SEVA plasmids. The presence of this device restored the production of the GG in a ggpS deficient mutant validating the functionality of the tools/device developed in this study.
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Affiliation(s)
- Eunice A Ferreira
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal.,ICBAS - Instituto de Ciências Biomédicas Abel Salazar Universidade do Porto, Porto, Portugal
| | - Catarina C Pacheco
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal
| | - Filipe Pinto
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal.,School of Biological Sciences, University of Edinburgh, Edinburgh, UK.,Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
| | - José Pereira
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal
| | - Pedro Lamosa
- Instituto de Tecnologia Química e Biológica António Xavier, ITQB NOVA, Oeiras, Portugal
| | - Paulo Oliveira
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal
| | - Boris Kirov
- CNRS-UMR8030 Laboratoire iSSB and Université Paris-Saclay and Université d'Évry and CEA DRF, IG, Genoscope, Évry, France.,ANP - Faculty of Automatics, TU - Sofia, Sofia, Bulgaria.,BioInfoTech Lab - RDIC, Sofia Tech Park, Sofia, Bulgaria
| | - Alfonso Jaramillo
- CNRS-UMR8030 Laboratoire iSSB and Université Paris-Saclay and Université d'Évry and CEA DRF, IG, Genoscope, Évry, France.,Warwick Integrative Synthetic Biology Centre and School of Life Sciences, University of Warwick, Coventry, UK.,Institute for Integrative Systems Biology (I2SysBio) University of Valencia-CSIC, Paterna, Spain
| | - Paula Tamagnini
- i3S - Instituto de Investigação e Inovação em Saúde Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular Universidade do Porto, Porto, Portugal.,Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Porto, Portugal
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58
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Jin H, Wang Y, Idoine A, Bhaya D. Construction of a Shuttle Vector Using an Endogenous Plasmid From the Cyanobacterium Synechocystis sp. PCC6803. Front Microbiol 2018; 9:1662. [PMID: 30087668 PMCID: PMC6066503 DOI: 10.3389/fmicb.2018.01662] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 07/04/2018] [Indexed: 12/21/2022] Open
Abstract
To advance synthetic biology in the photosynthetic cyanobacterium Synechocystis sp. PCC6803 (Syn6803), we constructed a shuttle vector with some versatile features. This shuttle vector, pSCB-YFP, consists of a putative replicon identified on the plasmid pCC5.2, the origin of replication of pMB1 from E. coli, as well as the YFP reporter gene and a spectinomycin/streptomycin resistance cassette. pSCB-YFP is stably maintained in Syn6803M (a motile strain that lacks the endogenous pCC5.2) and expresses YFP. In addition, we engineered a fragment into pSCB-YFP that has multiple cloning sites and other features such that this plasmid can also be used as an expression vector (pSCBe). The shuttle vector pSCB-YFP can be stably maintained for at least 50 generations without antibiotic selection. It is a high copy number plasmid and can stably co-exist with the RSF1010-based pPMQAK1-GFP.
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Affiliation(s)
- Haojie Jin
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, United States
| | - Yan Wang
- Department of Neurosurgery and Stanford Stroke Center, Stanford University, Stanford, CA, United States
| | - Adam Idoine
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, United States
| | - Devaki Bhaya
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, United States
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59
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Riboregulator elements as tools to engineer gene expression in cyanobacteria. Appl Microbiol Biotechnol 2018; 102:7717-7723. [DOI: 10.1007/s00253-018-9221-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 07/02/2018] [Accepted: 07/04/2018] [Indexed: 01/01/2023]
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60
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Liang Y, Hou J, Liu Y, Luo Y, Tang J, Cheng JJ, Daroch M. Textile Dye Decolorizing Synechococcus PCC7942 Engineered With CotA Laccase. Front Bioeng Biotechnol 2018; 6:95. [PMID: 30050901 PMCID: PMC6052094 DOI: 10.3389/fbioe.2018.00095] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 06/25/2018] [Indexed: 01/20/2023] Open
Abstract
Cyanobacteria are prokaryotic phototrophs capable of achieving high cellular densities with minimal inputs. These prokaryotic organisms can grow using sunlight as energy source and carbon dioxide as carbon source what makes them promising candidates as microbial cell factories for the production of numerous compounds such as chemicals, fuels, or biocatalysts. In this study, we have successfully designed and constructed using synthetic biology approach two recombinant strains of Synechococcus elongatus PCC7942 for heterologous expression of the industrially relevant Bacillus subtilis CotA laccase. One of the strains (PCC7942-NSI-CotA) was constructed through integration of the laccase gene into neutral site I of the cyanobacterial genome whilst the other (PCC7942-NSII-CotA) targeted neutral site II of the genome. Of the two strains the one with CotA laccase integrated in neutral site II (PCC7942-NSII-CotA) was superior in terms of growth rate and enzymatic activity toward typical laccase substrates: ABTS [2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonate)] and syringaldazine. That may suggest that two of the traditionally used neutral sites of S. elongatus PCC7942 are not equally suitable for the expression of certain transgenes. The PCC7942-NSII-CotA produced protein was capable of decolourising three classes of dyes namely: anthraquinonic-, azo-, and indigoid-type over 7 days of incubation making the strain a potentially useful microbial cell factory for the production of broad-spectrum biodegradation agent. Interestingly, presence of additional synthetic redox mediator ABTS had no effect on the degradation of these dyes.
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Affiliation(s)
- Yuanmei Liang
- School of Environment and Energy, Shenzhen Graduate School, Peking University, Shenzhen, China
| | - Juan Hou
- School of Environment and Energy, Shenzhen Graduate School, Peking University, Shenzhen, China
| | - Ying Liu
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Yifan Luo
- School of Environment and Energy, Shenzhen Graduate School, Peking University, Shenzhen, China
| | - Jie Tang
- School of Pharmacy and Bioengineering, Chengdu University, Chengdu, China
| | - Jay J. Cheng
- School of Environment and Energy, Shenzhen Graduate School, Peking University, Shenzhen, China
- Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC, United States
| | - Maurycy Daroch
- School of Environment and Energy, Shenzhen Graduate School, Peking University, Shenzhen, China
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61
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Sun T, Li S, Song X, Diao J, Chen L, Zhang W. Toolboxes for cyanobacteria: Recent advances and future direction. Biotechnol Adv 2018; 36:1293-1307. [DOI: 10.1016/j.biotechadv.2018.04.007] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/09/2018] [Accepted: 04/26/2018] [Indexed: 12/20/2022]
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62
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Sengupta A, Pakrasi HB, Wangikar PP. Recent advances in synthetic biology of cyanobacteria. Appl Microbiol Biotechnol 2018; 102:5457-5471. [PMID: 29744631 DOI: 10.1007/s00253-018-9046-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/23/2018] [Accepted: 04/24/2018] [Indexed: 12/11/2022]
Abstract
Cyanobacteria are attractive hosts that can be engineered for the photosynthetic production of fuels, fine chemicals, and proteins from CO2. Moreover, the responsiveness of these photoautotrophs towards different environmental signals, such as light, CO2, diurnal cycle, and metals make them potential hosts for the development of biosensors. However, engineering these hosts proves to be a challenging and lengthy process. Synthetic biology can make the process of biological engineering more predictable through the use of standardized biological parts that are well characterized and tools to assemble them. While significant progress has been made with model heterotrophic organisms, many of the parts and tools are not portable in cyanobacteria. Therefore, efforts are underway to develop and characterize parts derived from cyanobacteria. In this review, we discuss the reported parts and tools with the objective to develop cyanobacteria as cell factories or biosensors. We also discuss the issues related to characterization, tunability, portability, and the need to develop enabling technologies to engineer this "green" chassis.
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Affiliation(s)
- Annesha Sengupta
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India
| | - Himadri B Pakrasi
- Department of Biology, Washington University, St. Louis, MO, USA.,Department of Energy, Environmental and Chemical Engineering, Washington University, St. Louis, MO, USA
| | - Pramod P Wangikar
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India. .,DBT-Pan IIT Center for Bioenergy, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India. .,Wadhwani Research Center for Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
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63
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Photomixotrophic chemical production in cyanobacteria. Curr Opin Biotechnol 2018; 50:65-71. [DOI: 10.1016/j.copbio.2017.11.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/11/2017] [Accepted: 11/13/2017] [Indexed: 11/19/2022]
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64
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Thiel K, Mulaku E, Dandapani H, Nagy C, Aro EM, Kallio P. Translation efficiency of heterologous proteins is significantly affected by the genetic context of RBS sequences in engineered cyanobacterium Synechocystis sp. PCC 6803. Microb Cell Fact 2018; 17:34. [PMID: 29499707 PMCID: PMC5834881 DOI: 10.1186/s12934-018-0882-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 02/23/2018] [Indexed: 12/26/2022] Open
Abstract
Background Photosynthetic cyanobacteria have been studied as potential host organisms for direct solar-driven production of different carbon-based chemicals from CO2 and water, as part of the development of sustainable future biotechnological applications. The engineering approaches, however, are still limited by the lack of comprehensive information on most optimal expression strategies and validated species-specific genetic elements which are essential for increasing the intricacy, predictability and efficiency of the systems. This study focused on the systematic evaluation of the key translational control elements, ribosome binding sites (RBS), in the cyanobacterial host Synechocystis sp. PCC 6803, with the objective of expanding the palette of tools for more rigorous engineering approaches. Results An expression system was established for the comparison of 13 selected RBS sequences in Synechocystis, using several alternative reporter proteins (sYFP2, codon-optimized GFPmut3 and ethylene forming enzyme) as quantitative indicators of the relative translation efficiencies. The set-up was shown to yield highly reproducible expression patterns in independent analytical series with low variation between biological replicates, thus allowing statistical comparison of the activities of the different RBSs in vivo. While the RBSs covered a relatively broad overall expression level range, the downstream gene sequence was demonstrated in a rigorous manner to have a clear impact on the resulting translational profiles. This was expected to reflect interfering sequence-specific mRNA-level interaction between the RBS and the coding region, yet correlation between potential secondary structure formation and observed translation levels could not be resolved with existing in silico prediction tools. Conclusions The study expands our current understanding on the potential and limitations associated with the regulation of protein expression at translational level in engineered cyanobacteria. The acquired information can be used for selecting appropriate RBSs for optimizing over-expression constructs or multicistronic pathways in Synechocystis, while underlining the complications in predicting the activity due to gene-specific interactions which may reduce the translational efficiency for a given RBS-gene combination. Ultimately, the findings emphasize the need for additional characterized insulator sequence elements to decouple the interaction between the RBS and the coding region for future engineering approaches. Electronic supplementary material The online version of this article (10.1186/s12934-018-0882-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kati Thiel
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Edita Mulaku
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Hariharan Dandapani
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Csaba Nagy
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland
| | - Pauli Kallio
- Molecular Plant Biology, Department of Biochemistry, University of Turku, 20014, Turku, Finland.
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65
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Wang B, Eckert C, Maness PC, Yu J. A Genetic Toolbox for Modulating the Expression of Heterologous Genes in the Cyanobacterium Synechocystis sp. PCC 6803. ACS Synth Biol 2018; 7:276-286. [PMID: 29232504 DOI: 10.1021/acssynbio.7b00297] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Cyanobacteria, genetic models for photosynthesis research for decades, have recently become attractive hosts for producing renewable fuels and chemicals, owing to their genetic tractability, relatively fast growth, and their ability to utilize sunlight, fix carbon dioxide, and in some cases, fix nitrogen. Despite significant advances, there is still an urgent demand for synthetic biology tools in order to effectively manipulate genetic circuits in cyanobacteria. In this study, we have compared a total of 17 natural and chimeric promoters, focusing on expression of the ethylene-forming enzyme (EFE) in the cyanobacterium Synechocystis sp. PCC 6803. We report the finding that the E. coli σ70 promoter Ptrc is superior compared to the previously reported strong promoters, such as PcpcB and PpsbA, for the expression of EFE. In addition, we found that the EFE expression level was very sensitive to the 5'-untranslated region upstream of the open reading frame. A library of ribosome binding sites (RBSs) was rationally designed and was built and systematically characterized. We demonstrate a strategy complementary to the RBS prediction software to facilitate the rational design of an RBS library to optimize the gene expression in cyanobacteria. Our results show that the EFE expression level is dramatically enhanced through these synthetic biology tools and is no longer the rate-limiting step for cyanobacterial ethylene production. These systematically characterized promoters and the RBS design strategy can serve as useful tools to tune gene expression levels and to identify and mitigate metabolic bottlenecks in cyanobacteria.
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Affiliation(s)
- Bo Wang
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Carrie Eckert
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
- Renewable
and Sustainable Energy Institute, University of Colorado, Boulder, 4001 Discovery Drive, Boulder, Colorado 80303, United States
| | - Pin-Ching Maness
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Jianping Yu
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
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66
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Du W, Burbano PC, Hellingwerf KJ, Branco Dos Santos F. Challenges in the Application of Synthetic Biology Toward Synthesis of Commodity Products by Cyanobacteria via "Direct Conversion". ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1080:3-26. [PMID: 30091089 DOI: 10.1007/978-981-13-0854-3_1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cyanobacterial direct conversion of CO2 to several commodity chemicals has been recognized as a potential contributor to support the much-needed sustainable development of human societies. However, the feasibility of this "green conversion" hinders on our ability to overcome the hurdles presented by the natural evolvability of microbes. The latter may result in the genetic instability of engineered cyanobacterial strains leading to impaired productivity. This challenge is general to any "cell factory" approach in which the cells grow for multiple generations, and based on several studies carried out in different microbial hosts, we could identify that three distinct strategies have been proposed to tackle it. These are (1) to reduce microbial evolvability by decreasing the native mutation rate, (2) to align product formation with cell growth/fitness, and, paradoxically, (3) to efficiently reallocate cellular resources to product formation by uncoupling it from growth. The implementation of either of these strategies requires an advanced synthetic biology toolkit. Here, we review the existing methods available for cyanobacteria and identify areas of focus in which specific developments are still needed. Furthermore, we discuss how potentially stabilizing strategies may be used in combination leading to further increases of productivity while ensuring the stability of the cyanobacterial-based direct conversion process.
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Affiliation(s)
- Wei Du
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Patricia Caicedo Burbano
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Klaas J Hellingwerf
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Filipe Branco Dos Santos
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, Faculty of Sciences, University of Amsterdam, Amsterdam, The Netherlands.
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67
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AraBAD Based Toolkit for Gene Expression and Metabolic Robustness Improvement in Synechococcus elongatus. Sci Rep 2017; 7:18059. [PMID: 29273782 PMCID: PMC5741739 DOI: 10.1038/s41598-017-17035-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/20/2017] [Indexed: 12/14/2022] Open
Abstract
As a novel chemical production platform, controllable and inducible modules in Synechococcus elongatus plus the ability of working in diurnal conditions are necessary. To the endeavors, inducible promoters, such as PTrc, have been refined from Escherichia coli, but the inducer isopropyl-β-D-thiogalactoside may cause several side-effects. Meanwhile, to promote the efficiency, photomixotrophic cultivation has been applied in S. elongatus with the additional organic carbon sources. In this study, we developed L-arabinose based modules consisted of both the PBAD inducible promoter and the metabolism of L-arabinose in S. elongatus, since L-arabinose is an ideal heterologous feedstock for its availability and economic and environmental benefits. As expected, we achieved homogeneous and linear expression of the exogenous reporter through the PBAD promoter, and the biomass increased in diurnal light condition via introducing L-arabinose metabolism pathway. Moreover, the combined AraBAD based toolkit containing both the PBAD inducible module and the L-arabinose metabolism module could obtain gene expression and metabolic robustness improvement in S. elongatus. With the only additive L-arabinose, the novel strategy may generate a win-win scenario for both regulation and metabolism for autotrophic bio-production platforms.
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68
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Miao R, Liu X, Englund E, Lindberg P, Lindblad P. Isobutanol production in Synechocystis PCC 6803 using heterologous and endogenous alcohol dehydrogenases. Metab Eng Commun 2017; 5:45-53. [PMID: 29188183 PMCID: PMC5699533 DOI: 10.1016/j.meteno.2017.07.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 07/18/2017] [Accepted: 07/27/2017] [Indexed: 12/24/2022] Open
Abstract
Isobutanol is a flammable compound that can be used as a biofuel due to its high energy density and suitable physical and chemical properties. In this study, we examined the capacity of engineered strains of Synechocystis PCC 6803 containing the α-ketoisovalerate decarboxylase from Lactococcus lactis and different heterologous and endogenous alcohol dehydrogenases (ADH) for isobutanol production. A strain expressing an introduced kivd without any additional copy of ADH produced 3 mg L-1 OD750-1 isobutanol in 6 days. After the cultures were supplemented with external addition of isobutyraldehyde, the substrate for ADH, 60.8 mg L-1 isobutanol was produced after 24 h when OD750 was 0.8. The in vivo activities of four different ADHs, two heterologous and two putative endogenous in Synechocystis, were examined and the Synechocystis endogenous ADH encoded by slr1192 showed the highest efficiency for isobutanol production. Furthermore, the strain overexpressing the isobutanol pathway on a self-replicating vector with the strong Ptrc promoter showed significantly higher gene expression and isobutanol production compared to the corresponding strains expressing the same operon introduced on the genome. Hence, this study demonstrates that Synechocystis endogenous AHDs have a high capacity for isobutanol production, and identifies kivd encoded α-ketoisovalerate decarboxylase as one of the likely bottlenecks for further isobutanol production.
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Affiliation(s)
| | | | | | | | - Peter Lindblad
- Microbial chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
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69
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Su HY, Chou HH, Chow TJ, Lee TM, Chang JS, Huang WL, Chen HJ. Improvement of outdoor culture efficiency of cyanobacteria by over-expression of stress tolerance genes and its implication as bio-refinery feedstock. BIORESOURCE TECHNOLOGY 2017; 244:1294-1303. [PMID: 28457721 DOI: 10.1016/j.biortech.2017.04.074] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/02/2017] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
This study was undertaken to increase the biomass and carbohydrate productivities of a freshwater cyanobacterium Synechococcus elongatus under hot outdoor conditions through genetic manipulation to facilitate the application of using the cyanobacterial biomass as bio-refinery feedstocks. The stress tolerance genes (hspA, osmotin) were expressed in S. elongatus to improve their growth under various environment stresses of outdoor cultivation. The results revealed that over-expression of hspA and osmotin significantly improved temperature (45°C), high light intensity, and salt tolerances of S. elongatus cells, making it capable of efficiently growing in seawater under outdoor cultivation. The carbohydrate productivity of these stress tolerant strains was also 15-30-fold higher than that of the control strain, although the carbohydrate contents of the recombinant and control strains were similar. Our findings demonstrate that the genetic engineering for improved stresses tolerance in S. elongatus could facilitate the feasibility of using cyanobacteria as feedstock for bio-refinery industry.
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Affiliation(s)
- Hsiang-Yen Su
- Department of Biotechnology, Fooyin University, Kaohsiung 831, Taiwan; Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; Doctoral Degree Program in Marine Biotechnology, Academia Sinica, Taipei 115, Taiwan
| | - Hsiang-Hui Chou
- Department of Biotechnology, Fooyin University, Kaohsiung 831, Taiwan; Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Te-Jin Chow
- Department of Biotechnology, Fooyin University, Kaohsiung 831, Taiwan
| | - Tse-Min Lee
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; Doctoral Degree Program in Marine Biotechnology, Academia Sinica, Taipei 115, Taiwan; Department of Marine Biotechnology and Resources, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Jo-Shu Chang
- Department of Chemical Engineering, National Cheng-Kung University, Tainan 701, Taiwan; Reserach Center for Energy Technology and Strategy, National Cheng Kung University, Tainan 701, Taiwan
| | - Wen-Lii Huang
- Department of Agronomy, National Chiayi University, Chiayi 600, Taiwan
| | - Hsien-Jung Chen
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, Kaohsiung 804, Taiwan; Doctoral Degree Program in Marine Biotechnology, Academia Sinica, Taipei 115, Taiwan; Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
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70
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Vavitsas K, Rue EØ, Stefánsdóttir LK, Gnanasekaran T, Blennow A, Crocoll C, Gudmundsson S, Jensen PE. Responses of Synechocystis sp. PCC 6803 to heterologous biosynthetic pathways. Microb Cell Fact 2017; 16:140. [PMID: 28806958 PMCID: PMC5556357 DOI: 10.1186/s12934-017-0757-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/09/2017] [Indexed: 11/10/2022] Open
Abstract
Background There are an increasing number of studies regarding genetic manipulation of cyanobacteria to produce commercially interesting compounds. The majority of these works study the expression and optimization of a selected heterologous pathway, largely ignoring the wholeness and complexity of cellular metabolism. Regulation and response mechanisms are largely unknown, and even the metabolic pathways themselves are not fully elucidated. This poses a clear limitation in exploiting the rich biosynthetic potential of cyanobacteria. Results In this work, we focused on the production of two different compounds, the cyanogenic glucoside dhurrin and the diterpenoid 13R-manoyl oxide in Synechocystis PCC 6803. We used genome-scale metabolic modelling to study fluxes in individual reactions and pathways, and we determined the concentrations of key metabolites, such as amino acids, carotenoids, and chlorophylls. This allowed us to identify metabolic crosstalk between the native and the introduced metabolic pathways. Most results and simulations highlight the metabolic robustness of cyanobacteria, suggesting that the host organism tends to keep metabolic fluxes and metabolite concentrations steady, counteracting the effects of the heterologous pathway. However, the amino acid concentrations of the dhurrin-producing strain show an unexpected profile, where the perturbation levels were high in seemingly unrelated metabolites. Conclusions There is a wealth of information that can be derived by combining targeted metabolite identification and computer modelling as a frame of understanding. Here we present an example of how strain engineering approaches can be coupled to ‘traditional’ metabolic engineering with systems biology, resulting in novel and more efficient manipulation strategies. Electronic supplementary material The online version of this article (doi:10.1186/s12934-017-0757-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Konstantinos Vavitsas
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Emil Østergaard Rue
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | | | - Thiyagarajan Gnanasekaran
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.,ISBP-INSA de Toulouse, Avenue de Rangueil, 31077, Toulouse, France
| | - Andreas Blennow
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Christoph Crocoll
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - Steinn Gudmundsson
- Center for Systems Biology, University of Iceland, Sturlugata 8, 101, Reykjavik, Iceland
| | - Poul Erik Jensen
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark.
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71
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Lima S, Oliveira P, Tamagnini P. The secretion signal peptide of the cyanobacterial extracellular protein HesF is located at its C-terminus. FEMS Microbiol Lett 2017; 364:4036450. [PMID: 28859322 DOI: 10.1093/femsle/fnx160] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 07/25/2017] [Indexed: 11/14/2022] Open
Abstract
Cyanobacteria are photosynthetic prokaryotes, capable of sustaining their growth by converting sunlight into chemical energy by fixing CO2 into organic matter. The cyanobacterium Anabaena sp. PCC 7120 is also capable of fixing atmospheric nitrogen, a metabolic process that occurs in specialized cells, the heterocysts. During the process of heterocyst differentiation, drastic morphological changes occur to prepare the future differentiated cell to accommodate the nitrogen fixation metabolism, which is a highly O2-sensitive process. Recently, we identified an unknown extracellular protein (termed HesF) in Anabaena sp. PCC 7120 and found it to be required for the proper deposition of the polysaccharide layers in the heterocyst cell wall. HesF is a non-classical type I secretion system (T1SS)-dependent secreted substrate, and its secretion signal remained elusive. Here, we report that the secretion signal of HesF is located in its C-terminus. We present evidence that a heterologous reporter protein fused with HesF's secretion signal could be successfully expressed in heterocysts and secreted to the extracellular medium, following hesF's native regulation. This represents the first time that the secretion signal of a cyanobacterial T1SS-dependent substrate is identified, and demonstrates the feasibility of using cyanobacteria for selected protein expression and secretion.
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Affiliation(s)
- Steeve Lima
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.,Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, 4169-007 Porto, Portugal
| | - Paulo Oliveira
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Paula Tamagnini
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.,Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, 4169-007 Porto, Portugal
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72
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Esteves-Ferreira AA, Cavalcanti JHF, Vaz MGMV, Alvarenga LV, Nunes-Nesi A, Araújo WL. Cyanobacterial nitrogenases: phylogenetic diversity, regulation and functional predictions. Genet Mol Biol 2017; 40:261-275. [PMID: 28323299 PMCID: PMC5452144 DOI: 10.1590/1678-4685-gmb-2016-0050] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 12/21/2016] [Indexed: 12/21/2022] Open
Abstract
Cyanobacteria is a remarkable group of prokaryotic photosynthetic microorganisms, with several genera capable of fixing atmospheric nitrogen (N2) and presenting a wide range of morphologies. Although the nitrogenase complex is not present in all cyanobacterial taxa, it is spread across several cyanobacterial strains. The nitrogenase complex has also a high theoretical potential for biofuel production, since H2 is a by-product produced during N2 fixation. In this review we discuss the significance of a relatively wide variety of cell morphologies and metabolic strategies that allow spatial and temporal separation of N2 fixation from photosynthesis in cyanobacteria. Phylogenetic reconstructions based on 16S rRNA and nifD gene sequences shed light on the evolutionary history of the two genes. Our results demonstrated that (i) sequences of genes involved in nitrogen fixation (nifD) from several morphologically distinct strains of cyanobacteria are grouped in similarity with their morphology classification and phylogeny, and (ii) nifD genes from heterocytous strains share a common ancestor. By using this data we also discuss the evolutionary importance of processes such as horizontal gene transfer and genetic duplication for nitrogenase evolution and diversification. Finally, we discuss the importance of H2 synthesis in cyanobacteria, as well as strategies and challenges to improve cyanobacterial H2 production.
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Affiliation(s)
- Alberto A Esteves-Ferreira
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil.,Max-Planck-partner group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - João Henrique Frota Cavalcanti
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil.,Max-Planck-partner group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Marcelo Gomes Marçal Vieira Vaz
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil.,Max-Planck-partner group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Luna V Alvarenga
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil.,Max-Planck-partner group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Adriano Nunes-Nesi
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil.,Max-Planck-partner group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil
| | - Wagner L Araújo
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil.,Max-Planck-partner group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Viçosa, MG, Brazil
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73
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Global metabolic rewiring for improved CO 2 fixation and chemical production in cyanobacteria. Nat Commun 2017; 8:14724. [PMID: 28287087 PMCID: PMC5355792 DOI: 10.1038/ncomms14724] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 01/25/2017] [Indexed: 01/10/2023] Open
Abstract
Cyanobacteria have attracted much attention as hosts to recycle CO2 into valuable chemicals. Although cyanobacteria have been engineered to produce various compounds, production efficiencies are too low for commercialization. Here we engineer the carbon metabolism of Synechococcus elongatus PCC 7942 to improve glucose utilization, enhance CO2 fixation and increase chemical production. We introduce modifications in glycolytic pathways and the Calvin Benson cycle to increase carbon flux and redirect it towards carbon fixation. The engineered strain efficiently uses both CO2 and glucose, and produces 12.6 g l−1 of 2,3-butanediol with a rate of 1.1 g l−1 d−1 under continuous light conditions. Removal of native regulation enables carbon fixation and 2,3-butanediol production in the absence of light. This represents a significant step towards industrial viability and an excellent example of carbon metabolism plasticity. Cyanobacteria are promising biofactories to reduce atmospheric CO2 and convert it into chemicals. Here the authors engineer Synechococcus elongatus carbon metabolism to increase 2,3-butanediol production from glucose and CO2 under light and dark conditions.
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74
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Veetil VP, Angermayr SA, Hellingwerf KJ. Ethylene production with engineered Synechocystis sp PCC 6803 strains. Microb Cell Fact 2017; 16:34. [PMID: 28231787 PMCID: PMC5324202 DOI: 10.1186/s12934-017-0645-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 02/09/2017] [Indexed: 11/16/2022] Open
Abstract
Background Metabolic engineering and synthetic biology of cyanobacteria offer a promising sustainable alternative approach for fossil-based ethylene production, by using sunlight via oxygenic photosynthesis, to convert carbon dioxide directly into ethylene. Towards this, both well-studied cyanobacteria, i.e., Synechocystis sp PCC 6803 and Synechococcus elongatus PCC 7942, have been engineered to produce ethylene by introducing the ethylene-forming enzyme (Efe) from Pseudomonas syringae pv. phaseolicola PK2 (the Kudzu strain), which catalyzes the conversion of the ubiquitous tricarboxylic acid cycle intermediate 2-oxoglutarate into ethylene. Results This study focuses on Synechocystis sp PCC 6803 and shows stable ethylene production through the integration of a codon-optimized version of the efe gene under control of the Ptrc promoter and the core Shine–Dalgarno sequence (5′-AGGAGG-3′) as the ribosome-binding site (RBS), at the slr0168 neutral site. We have increased ethylene production twofold by RBS screening and further investigated improving ethylene production from a single gene copy of efe, using multiple tandem promoters and by putting our best construct on an RSF1010-based broad-host-self-replicating plasmid, which has a higher copy number than the genome. Moreover, to raise the intracellular amounts of the key Efe substrate, 2-oxoglutarate, from which ethylene is formed, we constructed a glycogen-synthesis knockout mutant (ΔglgC) and introduced the ethylene biosynthetic pathway in it. Under nitrogen limiting conditions, the glycogen knockout strain has increased intracellular 2-oxoglutarate levels; however, surprisingly, ethylene production was lower in this strain than in the wild-type background. Conclusion Making use of different RBS sequences, production of ethylene ranging over a 20-fold difference has been achieved. However, a further increase of production through multiple tandem promoters and a broad-host plasmid was not achieved speculating that the transcription strength and the gene copy number are not the limiting factors in our system.
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Affiliation(s)
- Vinod Puthan Veetil
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.,Reliance Technology Group, Reliance Industries Ltd., Navi Mumbai, India
| | - S Andreas Angermayr
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.,Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria
| | - Klaas J Hellingwerf
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands.
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75
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Kanno M, Atsumi S. Engineering an Obligate Photoautotrophic Cyanobacterium to Utilize Glycerol for Growth and Chemical Production. ACS Synth Biol 2017; 6:69-75. [PMID: 27643408 DOI: 10.1021/acssynbio.6b00239] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyanobacteria have attracted much attention as a means to directly recycle carbon dioxide into valuable chemicals that are currently produced from petroleum. However, the titers and productivities achieved are still far below the level required in industry. To make a more industrially applicable production scheme, glycerol, a byproduct of biodiesel production, can be used as an additional carbon source for photomixotrophic chemical production. Glycerol is an ideal candidate due to its availability and low cost. In this study, we found that a heterologous glycerol respiratory pathway enabled Synechococcus elongatus PCC 7942 to utilize extracellular glycerol. The engineered strain produced 761 mg/L of 2,3-butanediol in 48 h with a 290% increase over the control strain under continuous light conditions. Glycerol supplementation also allowed for continuous cell growth and 2,3-butanediol production in diurnal light conditions. These results highlight the potential of glycerol as an additional carbon source for photomixotrophic chemical production in cyanobacteria.
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Affiliation(s)
- Masahiro Kanno
- Department
of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
- Asahi Kasei Corporation, 2-1
Samejima, Fuji, Shizuoka 416-8501, Japan
| | - Shota Atsumi
- Department
of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
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76
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Zn2+-Inducible Expression Platform for Synechococcus sp. Strain PCC 7002 Based on the smtA Promoter/Operator and smtB Repressor. Appl Environ Microbiol 2017; 83:AEM.02491-16. [PMID: 27836841 DOI: 10.1128/aem.02491-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 11/07/2016] [Indexed: 12/31/2022] Open
Abstract
Synechococcus sp. strain PCC 7002 has been gaining significance as both a model system for photosynthesis research and for industrial applications. Until recently, the genetic toolbox for this model cyanobacterium was rather limited and relied primarily on tools that only allowed constitutive gene expression. This work describes a two-plasmid, Zn2+-inducible expression platform that is coupled with a zurA mutation, providing enhanced Zn2+ uptake. The control elements are based on the metal homeostasis system of a class II metallothionein gene (smtA7942) and its cognate SmtB7942 repressor from Synechococcus elongatus strain PCC 7942. Under optimal induction conditions, yellow fluorescent protein (YFP) levels were about half of those obtained with the strong, constitutive phycocyanin (cpcBA6803) promoter of Synechocystis sp. strain PCC 6803. This metal-inducible expression system in Synechococcus sp. strain PCC 7002 allowed the titratable gene expression of YFP that was up to 19-fold greater than the background level. This system was utilized successfully to control the expression of the Drosophila melanogaster β-carotene 15,15'-dioxygenase, NinaB, which is toxic when constitutively expressed from a strong promoter in Synechococcus sp. strain PCC 7002. Together, these properties establish this metal-inducible system as an additional useful tool that is capable of controlling gene expression for applications ranging from basic research to synthetic biology in Synechococcus sp. strain PCC 7002. IMPORTANCE This is the first metal-responsive expression system in cyanobacteria, to our knowledge, that does not exhibit low sensitivity for induction, which is one of the major hurdles for utilizing this class of genetic tools. In addition, high levels of expression can be generated that approximate those of established constitutive systems, with the added advantage of titratable control. Together, these properties establish this Zn2+-inducible system, which is based on the smtA7942 operator/promoter and smtB7942 repressor, as a versatile gene expression platform that expands the genetic toolbox of Synechococcus sp. strain PCC 7002.
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77
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Fu W, Chaiboonchoe A, Khraiwesh B, Nelson DR, Al-Khairy D, Mystikou A, Alzahmi A, Salehi-Ashtiani K. Algal Cell Factories: Approaches, Applications, and Potentials. Mar Drugs 2016; 14:md14120225. [PMID: 27983586 PMCID: PMC5192462 DOI: 10.3390/md14120225] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/02/2016] [Accepted: 12/05/2016] [Indexed: 12/26/2022] Open
Abstract
With the advent of modern biotechnology, microorganisms from diverse lineages have been used to produce bio-based feedstocks and bioactive compounds. Many of these compounds are currently commodities of interest, in a variety of markets and their utility warrants investigation into improving their production through strain development. In this review, we address the issue of strain improvement in a group of organisms with strong potential to be productive “cell factories”: the photosynthetic microalgae. Microalgae are a diverse group of phytoplankton, involving polyphyletic lineage such as green algae and diatoms that are commonly used in the industry. The photosynthetic microalgae have been under intense investigation recently for their ability to produce commercial compounds using only light, CO2, and basic nutrients. However, their strain improvement is still a relatively recent area of work that is under development. Importantly, it is only through appropriate engineering methods that we may see the full biotechnological potential of microalgae come to fruition. Thus, in this review, we address past and present endeavors towards the aim of creating productive algal cell factories and describe possible advantageous future directions for the field.
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Affiliation(s)
- Weiqi Fu
- Division of Science and Math, New York University Abu Dhabi, P.O. Box 129188 Saadiyat Island, Abu Dhabi, UAE.
| | - Amphun Chaiboonchoe
- Division of Science and Math, New York University Abu Dhabi, P.O. Box 129188 Saadiyat Island, Abu Dhabi, UAE.
| | - Basel Khraiwesh
- Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188 Saadiyat Island, Abu Dhabi, UAE.
| | - David R Nelson
- Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188 Saadiyat Island, Abu Dhabi, UAE.
| | - Dina Al-Khairy
- Division of Science and Math, New York University Abu Dhabi, P.O. Box 129188 Saadiyat Island, Abu Dhabi, UAE.
| | - Alexandra Mystikou
- Division of Science and Math, New York University Abu Dhabi, P.O. Box 129188 Saadiyat Island, Abu Dhabi, UAE.
| | - Amnah Alzahmi
- Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188 Saadiyat Island, Abu Dhabi, UAE.
| | - Kourosh Salehi-Ashtiani
- Division of Science and Math, New York University Abu Dhabi, P.O. Box 129188 Saadiyat Island, Abu Dhabi, UAE.
- Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188 Saadiyat Island, Abu Dhabi, UAE.
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78
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Martínez-García E, de Lorenzo V. The quest for the minimal bacterial genome. Curr Opin Biotechnol 2016; 42:216-224. [DOI: 10.1016/j.copbio.2016.09.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 01/09/2023]
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80
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Englund E, Liang F, Lindberg P. Evaluation of promoters and ribosome binding sites for biotechnological applications in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Sci Rep 2016; 6:36640. [PMID: 27857166 PMCID: PMC5114575 DOI: 10.1038/srep36640] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 10/17/2016] [Indexed: 01/21/2023] Open
Abstract
For effective metabolic engineering, a toolbox of genetic components that enables predictable control of gene expression is needed. Here we present a systematic study of promoters and ribosome binding sites in the unicellular cyanobacterium Synechocystis sp. PCC 6803. A set of metal ion inducible promoters from Synechocystis were compared to commonly used constitutive promoters, by measuring fluorescence of a reporter protein in a standardized setting to allow for accurate comparisons of promoter activity. The most versatile and useful promoter was found to be PnrsB, which from a relatively silent expression could be induced almost 40-fold, nearly up to the activity of the strong psbA2 promoter. By varying the concentrations of the two metal ion inducers Ni2+ and Co2+, expression from the promoter was highly tunable, results that were reproduced with PnrsB driving ethanol production. The activities of several ribosomal binding sites were also measured, and tested in parallel in Synechocystis and Escherichia coli. The results of the study add useful information to the Synechocystis genetic toolbox for biotechnological applications.
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Affiliation(s)
- Elias Englund
- Department of Chemistry - Ångström, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
| | - Feiyan Liang
- Department of Chemistry - Ångström, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
| | - Pia Lindberg
- Department of Chemistry - Ångström, Uppsala University, Box 523, SE-751 20 Uppsala, Sweden
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81
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Ruffing AM, Jensen TJ, Strickland LM. Genetic tools for advancement of Synechococcus sp. PCC 7002 as a cyanobacterial chassis. Microb Cell Fact 2016; 15:190. [PMID: 27832791 PMCID: PMC5105302 DOI: 10.1186/s12934-016-0584-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/28/2016] [Indexed: 11/10/2022] Open
Abstract
Background Successful implementation of modified cyanobacteria as hosts for industrial applications requires the development of a cyanobacterial chassis. The cyanobacterium Synechococcus sp. PCC 7002 embodies key attributes for an industrial host, including a fast growth rate and high salt, light, and temperature tolerances. This study addresses key limitations in the advancement of Synechococcus sp. PCC 7002 as an industrial chassis. Results Tools for genome integration were developed and characterized, including several putative neutral sites for genome integration. The minimum homology arm length for genome integration in Synechococcus sp. PCC 7002 was determined to be approximately 250 bp. Three fluorescent protein reporters (hGFP, Ypet, and mOrange) were characterized for gene expression, microscopy, and flow cytometry applications in Synechococcus sp. PCC 7002. Of these three proteins, the yellow fluorescent protein (Ypet) had the best optical properties for minimal interference with the native photosynthetic pigments and for detection using standard microscopy and flow cytometry optics. Twenty-five native promoters were characterized as tools for recombinant gene expression in Synechococcus sp. PCC 7002 based on previous RNA-seq results. This characterization included comparisons of protein and mRNA levels as well as expression under both continuous and diurnal light conditions. Promoters A2520 and A2579 were found to have strong expression in Synechococcus sp. PCC 7002 while promoters A1930, A1961, A2531, and A2813 had moderate expression. Promoters A2520 and A2813 showed more than twofold increases in gene expression under light conditions compared to dark, suggesting these promoters may be useful tools for engineering diurnal regulation. Conclusions The genome integration, fluorescent protein, and promoter tools developed in this study will help to advance Synechococcus sp. PCC 7002 as a cyanobacterial chassis. The long minimum homology arm length for Synechococcus sp. PCC 7002 genome integration indicates native exonuclease activity or a low efficiency of homologous recombination. Low correlation between transcript and protein levels in Synechococcus sp. PCC 7002 suggests that transcriptomic data are poor selection criteria for promoter tool development. Lastly, the conventional strategy of using promoters from photosynthetic operons as strong promoter tools is debunked, as promoters from hypothetical proteins (A2520 and A2579) were found to have much higher expression levels. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0584-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anne M Ruffing
- Department of Bioenergy and Defense Technologies, Sandia National Laboratories, P.O. Box 5800, MS 1413, Albuquerque, NM, 87185-1413, USA.
| | - Travis J Jensen
- Department of Bioenergy and Defense Technologies, Sandia National Laboratories, P.O. Box 5800, MS 1413, Albuquerque, NM, 87185-1413, USA
| | - Lucas M Strickland
- Department of Bioenergy and Defense Technologies, Sandia National Laboratories, P.O. Box 5800, MS 1413, Albuquerque, NM, 87185-1413, USA
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82
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The two Dps proteins, NpDps2 and NpDps5, are involved in light-induced oxidative stress tolerance in the N 2-fixing cyanobacterium Nostoc punctiforme. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1766-1776. [PMID: 27528559 DOI: 10.1016/j.bbabio.2016.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/09/2016] [Accepted: 08/11/2016] [Indexed: 11/23/2022]
Abstract
Cyanobacteria are photosynthetic prokaryotes that are considered biotechnologically prominent organisms for production of high-value compounds. Cyanobacteria are subject to high-light intensities, which is a challenge that needs to be addressed in design of efficient bio-engineered photosynthetic organisms. Dps proteins are members of the ferritin superfamily and are omnipresent in prokaryotes. They play a major role in oxidative stress protection and iron homeostasis. The filamentous, heterocyst-forming Nostoc punctiforme, has five Dps proteins. In this study we elucidated the role of these Dps proteins in acclimation to high light intensity, the gene loci organization and the transcriptional regulation of all five dps genes in N. punctiforme was revealed, and dps-deletion mutant strains were used in physiological characterization. Two mutants defective in Dps2 and Dps5 activity displayed a reduced fitness under increased illumination, as well as a differential Photosystem (PS) stoichiometry, with an elevated Photosystem II to Photosystem I ratio in the dps5 deletion strain. This work establishes a Dps-mediated link between light tolerance, H2O2 detoxification, and iron homeostasis, and provides further evidence on the non-redundant role of multiple Dps proteins in this multicellular cyanobacterium.
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83
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Moosavi Zenooz A, Zokaee Ashtiani F, Ranjbar R, Javadi N. Synechococcus sp. (PTCC 6021) cultivation under different light irradiances—Modeling of growth rate-light response. Prep Biochem Biotechnol 2016; 46:567-74. [DOI: 10.1080/10826068.2015.1084931] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
| | | | - Reza Ranjbar
- Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran
- Algaebiotech B.V., Weesp, The Netherlands
| | - Najvan Javadi
- Department of Chemical Engineering, Amirkabir University of Technology, Tehran, Iran
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84
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McEwen JT, Kanno M, Atsumi S. 2,3 Butanediol production in an obligate photoautotrophic cyanobacterium in dark conditions via diverse sugar consumption. Metab Eng 2016; 36:28-36. [DOI: 10.1016/j.ymben.2016.03.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 02/14/2016] [Accepted: 03/11/2016] [Indexed: 10/22/2022]
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85
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Nielsen AZ, Mellor SB, Vavitsas K, Wlodarczyk AJ, Gnanasekaran T, Perestrello Ramos H de Jesus M, King BC, Bakowski K, Jensen PE. Extending the biosynthetic repertoires of cyanobacteria and chloroplasts. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 87:87-102. [PMID: 27005523 DOI: 10.1111/tpj.13173] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 03/16/2016] [Accepted: 03/18/2016] [Indexed: 05/20/2023]
Abstract
Chloroplasts in plants and algae and photosynthetic microorganisms such as cyanobacteria are emerging hosts for sustainable production of valuable biochemicals, using only inorganic nutrients, water, CO2 and light as inputs. In the past decade, many bioengineering efforts have focused on metabolic engineering and synthetic biology in the chloroplast or in cyanobacteria for the production of fuels, chemicals and complex, high-value bioactive molecules. Biosynthesis of all these compounds can be performed in photosynthetic organelles/organisms by heterologous expression of the appropriate pathways, but this requires optimization of carbon flux and reducing power, and a thorough understanding of regulatory pathways. Secretion or storage of the compounds produced can be exploited for the isolation or confinement of the desired compounds. In this review, we explore the use of chloroplasts and cyanobacteria as biosynthetic compartments and hosts, and we estimate the levels of production to be expected from photosynthetic hosts in light of the fraction of electrons and carbon that can potentially be diverted from photosynthesis. The supply of reducing power, in the form of electrons derived from the photosynthetic light reactions, appears to be non-limiting, but redirection of the fixed carbon via precursor molecules presents a challenge. We also discuss the available synthetic biology tools and the need to expand the molecular toolbox to facilitate cellular reprogramming for increased production yields in both cyanobacteria and chloroplasts.
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Affiliation(s)
- Agnieszka Zygadlo Nielsen
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Silas Busck Mellor
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Konstantinos Vavitsas
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Artur Jacek Wlodarczyk
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Thiyagarajan Gnanasekaran
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Maria Perestrello Ramos H de Jesus
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Brian Christopher King
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Kamil Bakowski
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Poul Erik Jensen
- Copenhagen Plant Science Center, VILLUM Research Center for Plant Plasticity, Center for Synthetic Biology 'bioSYNergy', Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
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86
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Singh JS, Kumar A, Rai AN, Singh DP. Cyanobacteria: A Precious Bio-resource in Agriculture, Ecosystem, and Environmental Sustainability. Front Microbiol 2016; 7:529. [PMID: 27148218 PMCID: PMC4838734 DOI: 10.3389/fmicb.2016.00529] [Citation(s) in RCA: 168] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/31/2016] [Indexed: 12/29/2022] Open
Abstract
Keeping in view, the challenges concerning agro-ecosystem and environment, the recent developments in biotechnology offers a more reliable approach to address the food security for future generations and also resolve the complex environmental problems. Several unique features of cyanobacteria such as oxygenic photosynthesis, high biomass yield, growth on non-arable lands and a wide variety of water sources (contaminated and polluted waters), generation of useful by-products and bio-fuels, enhancing the soil fertility and reducing green house gas emissions, have collectively offered these bio-agents as the precious bio-resource for sustainable development. Cyanobacterial biomass is the effective bio-fertilizer source to improve soil physico-chemical characteristics such as water-holding capacity and mineral nutrient status of the degraded lands. The unique characteristics of cyanobacteria include their ubiquity presence, short generation time and capability to fix the atmospheric N2. Similar to other prokaryotic bacteria, the cyanobacteria are increasingly applied as bio-inoculants for improving soil fertility and environmental quality. Genetically engineered cyanobacteria have been devised with the novel genes for the production of a number of bio-fuels such as bio-diesel, bio-hydrogen, bio-methane, synga, and therefore, open new avenues for the generation of bio-fuels in the economically sustainable manner. This review is an effort to enlist the valuable information about the qualities of cyanobacteria and their potential role in solving the agricultural and environmental problems for the future welfare of the planet.
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Affiliation(s)
- Jay Shankar Singh
- Department of Environmental Microbiology, Babasaheb Bhimrao Ambedkar UniversityLucknow, India
| | - Arun Kumar
- Department of Environmental Microbiology, Babasaheb Bhimrao Ambedkar UniversityLucknow, India
| | - Amar N. Rai
- Department of Biochemistry, North-Eastern Hill UniversityShillong, India
| | - Devendra P. Singh
- Department of Environmental Science, Babasaheb Bhimrao Ambedkar UniversityLucknow, India
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87
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Čelešnik H, Tanšek A, Tahirović A, Vižintin A, Mustar J, Vidmar V, Dolinar M. Biosafety of biotechnologically important microalgae: intrinsic suicide switch implementation in cyanobacterium Synechocystis sp. PCC 6803. Biol Open 2016; 5:519-28. [PMID: 27029902 PMCID: PMC4890671 DOI: 10.1242/bio.017129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In recent years, photosynthetic autotrophic cyanobacteria have attracted interest for biotechnological applications for sustainable production of valuable metabolites. Although biosafety issues can have a great impact on public acceptance of cyanobacterial biotechnology, biosafety of genetically modified cyanobacteria has remained largely unexplored. We set out to incorporate biocontainment systems in the model cyanobacterium Synechocystis sp. PCC 6803. Plasmid-encoded safeguards were constructed using the nonspecific nuclease NucA from Anabaena combined with different metal-ion inducible promoters. In this manner, conditional lethality was dependent on intracellular DNA degradation for regulated autokilling as well as preclusion of horizontal gene transfer. In cells carrying the suicide switch comprising the nucA gene fused to a variant of the copM promoter, efficient inducible autokilling was elicited. Parallel to nuclease-based safeguards, cyanobacterial toxin/antitoxin (TA) modules were examined in biosafety switches. Rewiring of Synechocystis TA pairs ssr1114/slr0664 and slr6101/slr6100 for conditional lethality using metal-ion responsive promoters resulted in reduced growth, rather than cell killing, suggesting cells could cope with elevated toxin levels. Overall, promoter properties and translation efficiency influenced the efficacy of biocontainment systems. Several metal-ion promoters were tested in the context of safeguards, and selected promoters, including a nrsB variant, were characterized by beta-galactosidase reporter assay. Summary: Biosafety of biotechnologically important microalgae was addressed by suicide switch implementation in cyanobacterium Synechocystis sp. PCC 6803. This is the first report of biocontainment safeguards in cyanobacteria.
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Affiliation(s)
- Helena Čelešnik
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Anja Tanšek
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Aneja Tahirović
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Angelika Vižintin
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Jernej Mustar
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Vita Vidmar
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Marko Dolinar
- Chair of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana 1000, Slovenia
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88
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Hernández-Prieto MA, Semeniuk TA, Giner-Lamia J, Futschik ME. The Transcriptional Landscape of the Photosynthetic Model Cyanobacterium Synechocystis sp. PCC6803. Sci Rep 2016; 6:22168. [PMID: 26923200 PMCID: PMC4770689 DOI: 10.1038/srep22168] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/09/2016] [Indexed: 01/03/2023] Open
Abstract
Cyanobacteria exhibit a great capacity to adapt to different environmental conditions through changes in gene expression. Although this plasticity has been extensively studied in the model cyanobacterium Synechocystis sp. PCC 6803, a detailed analysis of the coordinated transcriptional adaption across varying conditions is lacking. Here, we report a meta-analysis of 756 individual microarray measurements conducted in 37 independent studies-the most comprehensive study of the Synechocystis transcriptome to date. Using stringent statistical evaluation, we characterized the coordinated adaptation of Synechocystis' gene expression on systems level. Evaluation of the data revealed that the photosynthetic apparatus is subjected to greater changes in expression than other cellular components. Nevertheless, network analyses indicated a significant degree of transcriptional coordination of photosynthesis and various metabolic processes, and revealed the tight co-regulation of components of photosystems I, II and phycobilisomes. Detailed inspection of the integrated data led to the discovery a variety of regulatory patterns and novel putative photosynthetic genes. Intriguingly, global clustering analyses suggested contrasting transcriptional response of metabolic and regulatory genes stress to conditions. The integrated Synechocystis transcriptome can be accessed and interactively analyzed via the CyanoEXpress website (http://cyanoexpress.sysbiolab.eu).
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Affiliation(s)
- Miguel A. Hernández-Prieto
- Systems Biology and Bioinformatics Laboratory, Centre of Marine Sciences, University of Algarve, 8005-139 Faro, Portugal
| | - Trudi Ann Semeniuk
- Systems Biology and Bioinformatics Laboratory, Centre of Marine Sciences, University of Algarve, 8005-139 Faro, Portugal
| | - Joaquín Giner-Lamia
- Systems Biology and Bioinformatics Laboratory, Centre of Marine Sciences, University of Algarve, 8005-139 Faro, Portugal
| | - Matthias E. Futschik
- Systems Biology and Bioinformatics Laboratory, Centre of Marine Sciences, University of Algarve, 8005-139 Faro, Portugal
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89
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Heliopoulos NS, Galeou A, Papageorgiou SK, Favvas EP, Katsaros FK, Stamatakis K. Modified in situ antimicrobial susceptibility testing method based on cyanobacteria chlorophyll a fluorescence. J Microbiol Methods 2016; 121:1-4. [DOI: 10.1016/j.mimet.2015.12.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 12/03/2015] [Accepted: 12/03/2015] [Indexed: 11/29/2022]
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90
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Tantong S, Incharoensakdi A, Sirikantaramas S, Lindblad P. Potential of Synechocystis PCC 6803 as a novel cyanobacterial chassis for heterologous expression of enzymes in the trans-resveratrol biosynthetic pathway. Protein Expr Purif 2016; 121:163-8. [PMID: 26845578 DOI: 10.1016/j.pep.2016.01.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/29/2015] [Accepted: 01/29/2016] [Indexed: 12/12/2022]
Abstract
Selected model strains of phototrophic cyanobacteria have been genetically engineered for heterologous expression of numerous enzymes. In the present study, we initially explored the heterologous expression of enzymes involved in trans-resveratrol production, namely, the production of tyrosine ammonia-lyase, coumaroyl CoA-ligase, and stilbene synthase, in the unicellular cyanobacterium Synechocystis PCC 6803. Under the promoters Ptrc1Ocore and Ptrc1O, the respective genes were transcribed and translated into the corresponding soluble proteins at concentrations of 16-34 μg L(-1). The expression levels of these enzymes did not affect the growth rate of the cyanobacterial cells. Interestingly, coumaroyl CoA-ligase expression slightly increased the chlorophyll a content of the cells. Overall, our results suggest that the complete pathway of trans-resveratrol production can be engineered in Synechocystis PCC 6803.
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Affiliation(s)
- Supaluk Tantong
- Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
| | - Aran Incharoensakdi
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
| | - Supaart Sirikantaramas
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand; Omics Sciences and Bioinformatics Center, Chulalongkorn University, Bangkok 10330, Thailand.
| | - Peter Lindblad
- Microbial Chemistry, Science for Life Laboratory, Department of Chemistry - Ångström, Uppsala University, Box 523, SE-75120 Uppsala, Sweden.
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91
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Oliveira P, Martins NM, Santos M, Pinto F, Büttel Z, Couto NAS, Wright PC, Tamagnini P. The versatile TolC-like Slr1270 in the cyanobacteriumSynechocystissp. PCC 6803. Environ Microbiol 2016; 18:486-502. [DOI: 10.1111/1462-2920.13172] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 11/04/2015] [Accepted: 12/01/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Paulo Oliveira
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
| | - Nuno M. Martins
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
- Faculdade de Ciências; Departamento de Biologia; Universidade do Porto; Porto Portugal
| | - Marina Santos
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
| | - Filipe Pinto
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
| | - Zsófia Büttel
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
| | - Narciso A. S. Couto
- ChELSI Institute; Chemical and Biological Engineering; University of Sheffield; Sheffield UK
| | - Phillip C. Wright
- ChELSI Institute; Chemical and Biological Engineering; University of Sheffield; Sheffield UK
| | - Paula Tamagnini
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto Portugal
- Faculdade de Ciências; Departamento de Biologia; Universidade do Porto; Porto Portugal
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92
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Wlodarczyk A, Gnanasekaran T, Nielsen AZ, Zulu NN, Mellor SB, Luckner M, Thøfner JFB, Olsen CE, Mottawie MS, Burow M, Pribil M, Feussner I, Møller BL, Jensen PE. Metabolic engineering of light-driven cytochrome P450 dependent pathways into Synechocystis sp. PCC 6803. Metab Eng 2016; 33:1-11. [DOI: 10.1016/j.ymben.2015.10.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/23/2015] [Accepted: 10/27/2015] [Indexed: 12/13/2022]
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93
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Ohbayashi R, Akai H, Yoshikawa H, Hess WR, Watanabe S. A tightly inducible riboswitch system in Synechocystis sp. PCC 6803. J GEN APPL MICROBIOL 2016; 62:154-9. [DOI: 10.2323/jgam.2016.02.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Ryudo Ohbayashi
- Department of Bioscience, Tokyo University of Agriculture
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| | - Hideto Akai
- Department of Bioscience, Tokyo University of Agriculture
| | - Hirofumi Yoshikawa
- Department of Bioscience, Tokyo University of Agriculture
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| | - Wolfgang R. Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg
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94
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Englund E, Andersen-Ranberg J, Miao R, Hamberger B, Lindberg P. Metabolic Engineering of Synechocystis sp. PCC 6803 for Production of the Plant Diterpenoid Manoyl Oxide. ACS Synth Biol 2015; 4:1270-8. [PMID: 26133196 PMCID: PMC4685428 DOI: 10.1021/acssynbio.5b00070] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Forskolin is a high value diterpenoid with a broad range of pharmaceutical applications, naturally found in root bark of the plant Coleus forskohlii. Because of its complex molecular structure, chemical synthesis of forskolin is not commercially attractive. Hence, the labor and resource intensive extraction and purification from C. forskohlii plants remains the current source of the compound. We have engineered the unicellular cyanobacterium Synechocystis sp. PCC 6803 to produce the forskolin precursor 13R-manoyl oxide (13R-MO), paving the way for light driven biotechnological production of this high value compound. In the course of this work, a new series of integrative vectors for use in Synechocystis was developed and used to create stable lines expressing chromosomally integrated CfTPS2 and CfTPS3, the enzymes responsible for the formation of 13R-MO in C. forskohlii. The engineered strains yielded production titers of up to 0.24 mg g(-1) DCW 13R-MO. To increase the yield, 13R-MO producing strains were further engineered by introduction of selected enzymes from C. forskohlii, improving the titer to 0.45 mg g(-1) DCW. This work forms a basis for further development of production of complex plant diterpenoids in cyanobacteria.
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Affiliation(s)
- Elias Englund
- Department
of Chemistry-Ångström, Uppsala University, Box 523, SE-751
20 Uppsala, Sweden
| | - Johan Andersen-Ranberg
- Department
of Plant and Environmental Sciences, Center for Synthetic Biology
bioSYNergy, Faculty of Science, University of Copenhagen, Thorvaldsensvej
40, 1871 Frederiksberg
C, Copenhagen, Denmark
| | - Rui Miao
- Department
of Chemistry-Ångström, Uppsala University, Box 523, SE-751
20 Uppsala, Sweden
| | - Björn Hamberger
- Department
of Plant and Environmental Sciences, Center for Synthetic Biology
bioSYNergy, Faculty of Science, University of Copenhagen, Thorvaldsensvej
40, 1871 Frederiksberg
C, Copenhagen, Denmark
| | - Pia Lindberg
- Department
of Chemistry-Ångström, Uppsala University, Box 523, SE-751
20 Uppsala, Sweden
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95
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Ramey CJ, Barón-Sola Á, Aucoin HR, Boyle NR. Genome Engineering in Cyanobacteria: Where We Are and Where We Need To Go. ACS Synth Biol 2015; 4:1186-96. [PMID: 25985322 DOI: 10.1021/acssynbio.5b00043] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Genome engineering of cyanobacteria is a promising area of development in order to produce fuels, feedstocks, and value-added chemicals in a sustainable way. Unfortunately, the current state of genome engineering tools for cyanobacteria lags far behind those of model organisms such as Escherichia coli and Saccharomyces cerevisiae. In this review, we present the current state of synthetic biology tools for genome engineering efforts in the most widely used cyanobacteria strains and areas that need concerted research efforts to improve tool development. Cyanobacteria pose unique challenges to genome engineering efforts because their cellular biology differs significantly from other eubacteria; therefore, tools developed for other genera are not directly transferrable. Standardized parts, such as promoters and ribosome binding sites, which control gene expression, require characterization in cyanobacteria in order to have fully predictable results. The application of these tools to genome engineering efforts is also discussed; the ability to do genome-wide searching and to introduce multiple mutations simultaneously is an area that needs additional research in order to enable fast and efficient strain engineering.
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Affiliation(s)
- C. Josh Ramey
- Chemical and Biological Engineering
Department, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Ángel Barón-Sola
- Chemical and Biological Engineering
Department, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Hanna R. Aucoin
- Chemical and Biological Engineering
Department, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Nanette R. Boyle
- Chemical and Biological Engineering
Department, Colorado School of Mines, Golden, Colorado 80401, United States
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96
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Nozzi NE, Atsumi S. Genome Engineering of the 2,3-Butanediol Biosynthetic Pathway for Tight Regulation in Cyanobacteria. ACS Synth Biol 2015; 4:1197-204. [PMID: 25974153 DOI: 10.1021/acssynbio.5b00057] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cyanobacteria have gained popularity among the metabolic engineering community as a tractable photosynthetic host for renewable chemical production. However, though a number of successfully engineered production systems have been reported, long-term genetic stability remains an issue for cyanobacterial systems. The genetic engineering toolbox for cyanobacteria is largely lacking inducible systems for expression control. The characterization of tight regulation systems for use in cyanobacteria may help to alleviate this problem. In this work we explore the function of the IPTG inducible promoter P(L)lacO1 in the model cyanobacterium Synechococcus elongatus PCC 7942 as well as the effect of gene order within an operon on pathway expression. According to our experiments, P(L)lacO1 functions well as an inducible promoter in S. elongatus. Additionally, we found that gene order within an operon can strongly influence control of expression of each gene.
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Affiliation(s)
- Nicole E. Nozzi
- Department
of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Shota Atsumi
- Department
of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
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97
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Pinto F, Pacheco CC, Oliveira P, Montagud A, Landels A, Couto N, Wright PC, Urchueguía JF, Tamagnini P. Improving a Synechocystis-based photoautotrophic chassis through systematic genome mapping and validation of neutral sites. DNA Res 2015; 22:425-37. [PMID: 26490728 PMCID: PMC4675711 DOI: 10.1093/dnares/dsv024] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 09/15/2015] [Indexed: 01/04/2023] Open
Abstract
The use of microorganisms as cell factories frequently requires extensive molecular manipulation. Therefore, the identification of genomic neutral sites for the stable integration of ectopic DNA is required to ensure a successful outcome. Here we describe the genome mapping and validation of five neutral sites in the chromosome of Synechocystis sp. PCC 6803, foreseeing the use of this cyanobacterium as a photoautotrophic chassis. To evaluate the neutrality of these loci, insertion/deletion mutants were produced, and to assess their functionality, a synthetic green fluorescent reporter module was introduced. The constructed integrative vectors include a BioBrick-compatible multiple cloning site insulated by transcription terminators, constituting robust cloning interfaces for synthetic biology approaches. Moreover, Synechocystis mutants (chassis) ready to receive purpose-built synthetic modules/circuits are also available. This work presents a systematic approach to map and validate chromosomal neutral sites in cyanobacteria, and that can be extended to other organisms.
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Affiliation(s)
- Filipe Pinto
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150-180, Portugal Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Porto 4150-171, Portugal
| | - Catarina C Pacheco
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150-180, Portugal
| | - Paulo Oliveira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150-180, Portugal
| | - Arnau Montagud
- Instituto Universitario de Matemática Pura y Aplicada, Universitat Politècnica de València, Valencia 46022, Spain
| | - Andrew Landels
- ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S10 2TN, UK
| | - Narciso Couto
- ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S10 2TN, UK
| | - Phillip C Wright
- ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S10 2TN, UK
| | - Javier F Urchueguía
- Instituto Universitario de Matemática Pura y Aplicada, Universitat Politècnica de València, Valencia 46022, Spain
| | - Paula Tamagnini
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto 4150-180, Portugal Faculdade de Ciências, Departamento de Biologia, Universidade do Porto, Porto 4150-171, Portugal
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98
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Premethylation of foreign DNA improves integrative transformation efficiency in Synechocystis sp. strain PCC 6803. Appl Environ Microbiol 2015; 81:8500-6. [PMID: 26452551 DOI: 10.1128/aem.02575-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 09/22/2015] [Indexed: 01/11/2023] Open
Abstract
Restriction digestion of foreign DNA is one of the key biological barriers against genetic transformation in microorganisms. To establish a high-efficiency transformation protocol in the model cyanobacterium, Synechocystis sp. strain PCC 6803 (Synechocystis 6803), we investigated the effects of premethylation of foreign DNA on the integrative transformation of this strain. In this study, two type II methyltransferase-encoding genes, i.e., sll0729 (gene M) and slr0214 (gene C), were cloned from the chromosome of Synechocystis 6803 and expressed in Escherichia coli harboring an integration plasmid. After premethylation treatment in E. coli, the integration plasmid was extracted and used for transformation of Synechocystis 6803. The results showed that although expression of methyltransferase M had little impact on the transformation of Synechocystis 6803, expression of methyltransferase C resulted in 11- to 161-fold-higher efficiency in the subsequent integrative transformation of Synechocystis 6803. Effective expression of methyltransferase C, which could be achieved by optimizing the 5' untranslated region, was critical to efficient premethylation of the donor DNA and thus high transformation efficiency in Synechocystis 6803. Since premethylating foreign DNA prior to transforming Synechocystis avoids changing the host genetic background, the study thus provides an improved method for high-efficiency integrative transformation of Synechocystis 6803.
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99
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Immethun CM, Ng KM, DeLorenzo DM, Waldron-Feinstein B, Lee YC, Moon TS. Oxygen-responsive genetic circuits constructed in Synechocystis sp. PCC 6803. Biotechnol Bioeng 2015; 113:433-42. [PMID: 26264210 DOI: 10.1002/bit.25722] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 07/18/2015] [Accepted: 08/04/2015] [Indexed: 02/03/2023]
Abstract
As photoautotrophic prokaryotes, cyanobacteria are promising platforms for producing value-added bioproducts. However, few regulatory genetic parts and devices (e.g., inducible promoters and regulatory circuits) have been developed for these potential hosts. Furthermore, the devices that have been created respond only to a single input. To address these issues, we developed an inducible genetic circuit that generates heterologous proteins in response to oxygen, an environmental signal. To test its performance and utility in Synechocystis sp. PCC 6803, a model cyanobacterial strain, we connected this circuit to either heterologous nifHDK genes, which encode oxygen-sensitive nitrogenase's structural proteins, or a fluorescent protein gene. The circuit was transcriptionally activated to generate nifHDK transcripts or fluorescent output only in low oxygen conditions. We expanded the oxygen-responsive circuit into a more complex circuit by building a two-input AND gate, which allows Synechocystis to specifically control expression of the fluorescent reporter in response to two signals, low oxygen and high anhydrotetracycline. To our knowledge, the AND gate is the first complex logic circuit built in a cyanobacterial strain. This work expands the synthetic biology tools available for complex gene expression in cyanobacteria, increasing their potential as biotechnology platforms.
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Affiliation(s)
- Cheryl M Immethun
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Kenneth M Ng
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Drew M DeLorenzo
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Ben Waldron-Feinstein
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Ying-Chiang Lee
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri.
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100
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Fine-Tuning of Photoautotrophic Protein Production by Combining Promoters and Neutral Sites in the Cyanobacterium Synechocystis sp. Strain PCC 6803. Appl Environ Microbiol 2015. [PMID: 26209663 DOI: 10.1128/aem.01349-15] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cyanobacteria are photosynthetic cell factories that use solar energy to convert CO2 into useful products. Despite this attractive feature, the development of tools for engineering cyanobacterial chassis has lagged behind that for heterotrophs such as Escherichia coli or Saccharomyces cerevisiae. Heterologous genes in cyanobacteria are often integrated at presumptively "neutral" chromosomal sites, with unknown effects. We used transcriptome sequencing (RNA-seq) data for the model cyanobacterium Synechocystis sp. strain PCC 6803 to identify neutral sites from which no transcripts are expressed. We characterized the two largest such sites on the chromosome, a site on an endogenous plasmid, and a shuttle vector by integrating an enhanced yellow fluorescent protein (EYFP) expression cassette expressed from either the Pcpc560 or the Ptrc1O promoter into each locus. Expression from the endogenous plasmid was as much as 14-fold higher than that from the chromosome, with intermediate expression from the shuttle vector. The expression characteristics of each locus correlated predictably with the promoters used. These findings provide novel, characterized tools for synthetic biology and metabolic engineering in cyanobacteria.
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