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Ibrahim IM, Rowden SJL, Cramer WA, Howe CJ, Puthiyaveetil S. Thiol redox switches regulate the oligomeric state of cyanobacterial Rre1, RpaA, and RpaB response regulators. FEBS Lett 2022; 596:1533-1543. [PMID: 35353903 PMCID: PMC9321951 DOI: 10.1002/1873-3468.14340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/11/2022] [Accepted: 03/16/2022] [Indexed: 11/18/2022]
Abstract
Cyanobacteria employ two‐component sensor‐response regulator systems to monitor and respond to environmental challenges. The response regulators RpaA, RpaB, Rre1 and RppA are integral to circadian clock function and abiotic stress acclimation in cyanobacteria. RpaA, RpaB and Rre1 are known to interact with ferredoxin or thioredoxin, raising the possibility of their thiol regulation. Here, we report that Synechocystis sp. PCC 6803 Rre1, RpaA and RpaB exist as higher‐order oligomers under oxidising conditions and that reduced thioredoxin A converts them to monomers. We further show that these response regulators contain redox‐responsive cysteine residues with an Em7 around −300 mV. These findings suggest a direct thiol modulation of the activity of these response regulators, independent of their cognate sensor kinases.
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Affiliation(s)
- Iskander M Ibrahim
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Stephen J L Rowden
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - William A Cramer
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Christopher J Howe
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Sujith Puthiyaveetil
- Department of Biochemistry and Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
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2
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Mallén-Ponce MJ, Huertas MJ, Florencio FJ. Exploring the Diversity of the Thioredoxin Systems in Cyanobacteria. Antioxidants (Basel) 2022; 11:antiox11040654. [PMID: 35453339 PMCID: PMC9025218 DOI: 10.3390/antiox11040654] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 02/04/2023] Open
Abstract
Cyanobacteria evolved the ability to perform oxygenic photosynthesis using light energy to reduce CO2 from electrons extracted from water and form nutrients. These organisms also developed light-dependent redox regulation through the Trx system, formed by thioredoxins (Trxs) and thioredoxin reductases (TRs). Trxs are thiol-disulfide oxidoreductases that serve as reducing substrates for target enzymes involved in numerous processes such as photosynthetic CO2 fixation and stress responses. We focus on the evolutionary diversity of Trx systems in cyanobacteria and discuss their phylogenetic relationships. The study shows that most cyanobacteria contain at least one copy of each identified Trx, and TrxA is the only one present in all genomes analyzed. Ferredoxin thioredoxin reductase (FTR) is present in all groups except Gloeobacter and Prochlorococcus, where there is a ferredoxin flavin-thioredoxin reductase (FFTR). Our data suggest that both TRs may have coexisted in ancestral cyanobacteria together with other evolutionarily related proteins such as NTRC or DDOR, probably used against oxidative stress. Phylogenetic studies indicate that they have different evolutionary histories. As cyanobacteria diversified to occupy new habitats, some of these proteins were gradually lost in some groups. Finally, we also review the physiological relevance of redox regulation in cyanobacteria through the study of target enzymes.
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Affiliation(s)
- Manuel J. Mallén-Ponce
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain;
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, 41012 Sevilla, Spain
- Correspondence: (M.J.M.-P.); (M.J.H.)
| | - María José Huertas
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain;
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, 41012 Sevilla, Spain
- Correspondence: (M.J.M.-P.); (M.J.H.)
| | - Francisco J. Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain;
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, 41012 Sevilla, Spain
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3
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Migur A, Heyl F, Fuss J, Srikumar A, Huettel B, Steglich C, Prakash JSS, Reinhardt R, Backofen R, Owttrim GW, Hess WR. The temperature-regulated DEAD-box RNA helicase CrhR interactome: Autoregulation and photosynthesis-related transcripts. JOURNAL OF EXPERIMENTAL BOTANY 2021:erab416. [PMID: 34499142 DOI: 10.1093/jxb/erab416] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Indexed: 06/13/2023]
Abstract
RNA helicases play crucial functions in RNA biology. In plants, RNA helicases are encoded by large gene families, performing roles in abiotic stress responses, development, the post-transcriptional regulation of gene expression as well as house-keeping functions. Several of these RNA helicases are targeted to the organelles, mitochondria and chloroplasts. Cyanobacteria are the direct evolutionary ancestors of plant chloroplasts. The cyanobacterium Synechocystis 6803 encodes a single DEAD-box RNA helicase, CrhR, that is induced by a range of abiotic stresses, including low temperature. Though the ΔcrhR mutant exhibits a severe cold-sensitive phenotype, the physiological function(s) performed by CrhR have not been described. To identify transcripts interacting with CrhR, we performed RNA co-immunoprecipitation with extracts from a Synechocystis crhR deletion mutant expressing the FLAG-tagged native CrhR or a K57A mutated version with an anticipated enhanced RNA binding. The composition of the interactome was strikingly biased towards photosynthesis-associated and redox-controlled transcripts. A transcript highly enriched in all experiments was the crhR mRNA, suggesting an auto-regulatory molecular mechanism. The identified interactome explains the described physiological role of CrhR in response to the redox poise of the photosynthetic electron transport chain and characterizes CrhR as an enzyme with a diverse range of transcripts as molecular targets.
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Affiliation(s)
- Anzhela Migur
- Faculty of Biology, University of Freiburg, Schänzlestr., Freiburg, Germany
| | - Florian Heyl
- Department of Computer Science, University of Freiburg, Georges-Koehler-Allee, Freiburg, Germany
| | - Janina Fuss
- Max Planck-Genome-Centre Cologne, Carl-von-Linné-Weg, Köln, Germany
| | - Afshan Srikumar
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Bruno Huettel
- Max Planck-Genome-Centre Cologne, Carl-von-Linné-Weg, Köln, Germany
| | - Claudia Steglich
- Faculty of Biology, University of Freiburg, Schänzlestr., Freiburg, Germany
| | - Jogadhenu S S Prakash
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | | | - Rolf Backofen
- Department of Computer Science, University of Freiburg, Georges-Koehler-Allee, Freiburg, Germany
| | - George W Owttrim
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Wolfgang R Hess
- Faculty of Biology, University of Freiburg, Schänzlestr., Freiburg, Germany
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4
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Thioredoxin Dependent Changes in the Redox States of FurA from Anabaena sp. PCC 7120. Antioxidants (Basel) 2021; 10:antiox10060913. [PMID: 34199999 PMCID: PMC8229018 DOI: 10.3390/antiox10060913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 11/21/2022] Open
Abstract
FurA is a multifunctional regulator in cyanobacteria that contains five cysteines, four of them arranged into two CXXC motifs. Lack of a structural zinc ion enables FurA to develop disulfide reductase activity. In vivo, FurA displays several redox isoforms, and the oxidation state of its cysteines determines its activity as regulator and its ability to bind different metabolites. Because of the relationship between FurA and the control of genes involved in oxidative stress defense and photosynthetic metabolism, we sought to investigate the role of type m thioredoxin TrxA as a potential redox partner mediating dithiol-disulfide exchange reactions necessary to facilitate the interaction of FurA with its different ligands. Both in vitro cross-linking assays and in vivo two-hybrid studies confirmed the interaction between FurA and TrxA. Light to dark transitions resulted in reversible oxidation of a fraction of the regulator present in Anabaena sp. PCC7120. Reconstitution of an electron transport chain using E. coli NADPH-thioredoxin-reductase followed by alkylation of FurA reduced cysteines evidenced the ability of TrxA to reduce FurA. Furthermore, the use of site-directed mutants allowed us to propose a plausible mechanism for FurA reduction. These results point to TrxA as one of the redox partners that modulates FurA performance.
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5
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Yao L, Shabestary K, Björk SM, Asplund-Samuelsson J, Joensson HN, Jahn M, Hudson EP. Pooled CRISPRi screening of the cyanobacterium Synechocystis sp PCC 6803 for enhanced industrial phenotypes. Nat Commun 2020; 11:1666. [PMID: 32245970 PMCID: PMC7125299 DOI: 10.1038/s41467-020-15491-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 03/13/2020] [Indexed: 11/09/2022] Open
Abstract
Cyanobacteria are model organisms for photosynthesis and are attractive for biotechnology applications. To aid investigation of genotype-phenotype relationships in cyanobacteria, we develop an inducible CRISPRi gene repression library in Synechocystis sp. PCC 6803, where we aim to target all genes for repression. We track the growth of all library members in multiple conditions and estimate gene fitness. The library reveals several clones with increased growth rates, and these have a common upregulation of genes related to cyclic electron flow. We challenge the library with 0.1 M L-lactate and find that repression of peroxiredoxin bcp2 increases growth rate by 49%. Transforming the library into an L-lactate-secreting Synechocystis strain and sorting top lactate producers enriches clones with sgRNAs targeting nutrient assimilation, central carbon metabolism, and cyclic electron flow. In many examples, productivity can be enhanced by repression of essential genes, which are difficult to access by transposon insertion.
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Affiliation(s)
- Lun Yao
- Science for Life Laboratory, KTH - Royal Institute of Technology, SE-171 21, Stockholm, Sweden.,Department of Protein Science, KTH - Royal Institute of Technology, SE-106 91, Stockholm, Sweden
| | - Kiyan Shabestary
- Science for Life Laboratory, KTH - Royal Institute of Technology, SE-171 21, Stockholm, Sweden.,Department of Protein Science, KTH - Royal Institute of Technology, SE-106 91, Stockholm, Sweden
| | - Sara M Björk
- Science for Life Laboratory, KTH - Royal Institute of Technology, SE-171 21, Stockholm, Sweden.,Department of Protein Science, KTH - Royal Institute of Technology, SE-106 91, Stockholm, Sweden
| | - Johannes Asplund-Samuelsson
- Science for Life Laboratory, KTH - Royal Institute of Technology, SE-171 21, Stockholm, Sweden.,Department of Protein Science, KTH - Royal Institute of Technology, SE-106 91, Stockholm, Sweden
| | - Haakan N Joensson
- Science for Life Laboratory, KTH - Royal Institute of Technology, SE-171 21, Stockholm, Sweden.,Department of Protein Science, KTH - Royal Institute of Technology, SE-106 91, Stockholm, Sweden
| | - Michael Jahn
- Science for Life Laboratory, KTH - Royal Institute of Technology, SE-171 21, Stockholm, Sweden.,Department of Protein Science, KTH - Royal Institute of Technology, SE-106 91, Stockholm, Sweden
| | - Elton P Hudson
- Science for Life Laboratory, KTH - Royal Institute of Technology, SE-171 21, Stockholm, Sweden. .,Department of Protein Science, KTH - Royal Institute of Technology, SE-106 91, Stockholm, Sweden.
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6
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Riediger M, Kadowaki T, Nagayama R, Georg J, Hihara Y, Hess WR. Biocomputational Analyses and Experimental Validation Identify the Regulon Controlled by the Redox-Responsive Transcription Factor RpaB. iScience 2019; 15:316-331. [PMID: 31103851 PMCID: PMC6525291 DOI: 10.1016/j.isci.2019.04.033] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 04/05/2019] [Accepted: 04/24/2019] [Indexed: 11/24/2022] Open
Abstract
Oxygenic photosynthesis requires the coordination of environmental stimuli with the regulation of transcription. The transcription factor RpaB is conserved from the simplest unicellular cyanobacteria to complex eukaryotic algae, representing more than 1 billion years of evolution. To predict the RpaB-controlled regulon in the cyanobacterium Synechocystis, we analyzed the positional distribution of binding sites together with high-resolution mapping data of transcriptional start sites (TSSs). We describe more than 150 target promoters whose activity responds to fluctuating light conditions. Binding sites close to the TSS mediate repression, whereas sites centered ∼50 nt upstream mediate activation. Using complementary experimental approaches, we found that RpaB controls genes involved in photoprotection, cyclic electron flow and state transitions, photorespiration, and nirA and isiA for which we suggest cross-regulation with the transcription factors NtcA or FurA. The deep integration of RpaB with diverse photosynthetic gene functions makes it one of the most important and versatile transcriptional regulators. RpaB controls a complex regulon, widely beyond the photosynthetic machinery The expression of the RNA regulators IsrR, PsrR1, and others depends on RpaB RpaB exhibits cross-regulations with other transcription factors, NtcA and Fur RpaB is a crucial transcriptional regulator in a photosynthetic microorganism
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Affiliation(s)
- Matthias Riediger
- Genetics & Experimental Bioinformatics, Institute of Biology III, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Taro Kadowaki
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Ryuta Nagayama
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Jens Georg
- Genetics & Experimental Bioinformatics, Institute of Biology III, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Yukako Hihara
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan.
| | - Wolfgang R Hess
- Genetics & Experimental Bioinformatics, Institute of Biology III, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany; Freiburg Institute for Advanced Studies, University of Freiburg, Albertstr. 19, 79104 Freiburg, Germany.
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7
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Deschoenmaeker F, Mihara S, Niwa T, Taguchi H, Wakabayashi KI, Hisabori T. The Absence of Thioredoxin m1 and Thioredoxin C in Anabaena sp. PCC 7120 Leads to Oxidative Stress. PLANT & CELL PHYSIOLOGY 2018; 59:2432-2441. [PMID: 30101290 DOI: 10.1093/pcp/pcy163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/05/2018] [Indexed: 06/08/2023]
Abstract
Thioredoxin (Trx) family proteins perform redox regulation in cells, and they are involved in several other biological processes (e.g. oxidative stress tolerance). In the filamentous cyanobacterium Anabaena sp. PCC7120 (A. 7120), eight Trx isoforms have been identified via genomic analysis. Among these Trx isoforms, the absence of Trx-m1 and TrxC appears to result in oxidative stress in A. 7120 together with alterations of the thylakoid membrane structure and phycobiliprotein composition. To analyze the physiological changes in these Trx disruptants thoroughly, quantitative proteomics was applied. Certainly, the mutants exhibited similar alterations in the proteome including decreased relative abundance of phycobiliproteins and an increased level of proteins involved in amino acid and carbohydrate metabolism. Nevertheless, the results also indicated that the mutants exhibited changes in the relative abundance of different sets of proteins participating in reactive oxygen species detoxification, such as Fe-SOD in Δtrx-m1 and PrxQ in ΔtrxC, suggesting distinct functions of Trx-m1 and TrxC.
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Affiliation(s)
- Frédéric Deschoenmaeker
- Laboratory for Chemistry and Life Science, Institute for Innovative Research, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-ku, Yokohama, Japan
| | - Shoko Mihara
- Laboratory for Chemistry and Life Science, Institute for Innovative Research, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-ku, Yokohama, Japan
- Department of Life Science, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan
| | - Tatsuya Niwa
- Cell Biology Center, Tokyo Institute of Technology, Nagatsuta 4259-S2-19, Midori-ku, Yokohama, Japan
| | - Hideki Taguchi
- Cell Biology Center, Tokyo Institute of Technology, Nagatsuta 4259-S2-19, Midori-ku, Yokohama, Japan
| | - Ken-Ichi Wakabayashi
- Laboratory for Chemistry and Life Science, Institute for Innovative Research, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-ku, Yokohama, Japan
- Department of Life Science, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan
| | - Toru Hisabori
- Laboratory for Chemistry and Life Science, Institute for Innovative Research, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-ku, Yokohama, Japan
- Department of Life Science, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama, Japan
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Interaction of the GntR-family transcription factor Sll1961 with thioredoxin in the cyanobacterium Synechocystis sp. PCC 6803. Sci Rep 2018; 8:6666. [PMID: 29703909 PMCID: PMC5923263 DOI: 10.1038/s41598-018-25077-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 04/16/2018] [Indexed: 11/23/2022] Open
Abstract
Changes in the redox state of the photosynthetic electron transport chain act as a signal to trigger acclimation responses to environmental cues and thioredoxin has been suggested to work as a key factor connecting the redox change with transcriptional regulation in the cyanobacterium Synechocystis sp. PCC 6803. We screened for redox-dependent transcription factors interacting with thioredoxin M (TrxM) and isolated the GntR-type transcription factor Sll1961 previously reported to be involved in acclimation responses of the photosynthetic machinery. Biochemical analyses using recombinant Sll1961 proteins of wild type and mutants of three cysteine residues, C124, C229 and C307, revealed that an intramolecular disulfide bond is formed between C229 and C307 under oxidizing conditions and TrxM can reduce it by attacking C307. Sll1961 exists in a dimeric form of about 80 kDa both under reducing and oxidizing conditions. C124 can form an intermolecular disulfide bond but it is not essential for dimerization. Based on these observations, tertiary structure models of the Sll1961 homodimer and the Sll1961-TrxM complex were constructed.
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9
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Pei G, Niu X, Zhou Y, Chen L, Zhang W. Crosstalk of two-component signal transduction systems in regulating central carbohydrate and energy metabolism during autotrophic and photomixotrophic growth of Synechocystis sp. PCC 6803. Integr Biol (Camb) 2018; 9:485-496. [PMID: 28485419 DOI: 10.1039/c7ib00049a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Unicellular model cyanobacterium Synechocystis sp. PCC 6803 has received considerable attention as a sustainable energy resource because of its photosynthetic machinery. However, two-component signal transduction systems (TCSTSs) in regulating central carbohydrate and energy metabolism of cyanobacteria are still poorly understood due to their diversity and functional complication. In this study, by comparing the growth of knockout mutants of 44 response regulators (RRs) of TCSTSs in Synechocystis, several RR mutants demonstrating differential growth patterns were identified under auto- or photomixotrophic conditions. However, in spite of no growth difference observed for the remaining RR mutants, liquid chromatography-mass spectrometry based metabolomic profile analysis showed that a widespread crosstalk of TCSTSs in regulating central carbohydrate and energy metabolism of Synechocystis was identified, while most of them showed diverse patterns during different trophic types or growth stages. Furthermore, an integrative analysis between evolutionary relationships and metabolomic profiles revealed some pairs of paralogous RRs with highly functional convergence, suggesting the possible conserved functions of Synechocystis TCSTSs during evolution. This study laid an important basis for understanding the function of TCSTSs in photosynthetic cyanobacteria.
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Affiliation(s)
- Guangsheng Pei
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, P. R. China.
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10
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Kadowaki T, Nagayama R, Georg J, Nishiyama Y, Wilde A, Hess WR, Hihara Y. A Feed-Forward Loop Consisting of the Response Regulator RpaB and the Small RNA PsrR1 Controls Light Acclimation of Photosystem I Gene Expression in the Cyanobacterium Synechocystis sp. PCC 6803. PLANT & CELL PHYSIOLOGY 2016; 57:813-823. [PMID: 26872833 DOI: 10.1093/pcp/pcw028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 01/30/2016] [Indexed: 06/05/2023]
Abstract
Since cyanobacteria need to decrease PSI content to avoid absorption of excess light energy, down-regulation of PSI gene expression is one of the key characteristics of the high-light (HL) acclimation response. The transcriptional regulator RpaB and the small RNA PsrR1 (photosynthesis regulatory RNA1) have been suggested to be the two most critical factors for this response in Synechocystis sp. PCC 6803. In this study, we found that the HLR1 DNA-binding motif, the recognition sequence for RpaB, is highly conserved in the core promoter region of the psrR1 gene among cyanobacterial species. Gel mobility shift assay revealed that RpaB binds to the HLR1 sequence of psrR1 in vitro. RNA gel blot analysis together with chromatin affinity purification (ChAP) analysis suggested that PSI genes are activated and the psrR1 gene is repressed by the binding of RpaB under low-light (LL) conditions. A decrease in DNA binding affinity of RpaB occurs within 5 min after the shift from LL to HL conditions, leading to the prompt decrease in PSI promoter activity together with derepression of psrR1 gene expression. Accumulating PsrR1 molecules then prevent translation from pre-existing PSI transcripts. By this dual repression at transcriptional and post-transcriptional levels, rapid and strict down-regulation of PSI expression under HL is secured. Our findings suggest that RpaB and PsrR1 constitute a feed-forward loop for the regulation of PSI gene expression to achieve a rapid acclimation response to the damaging HL conditions.
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Affiliation(s)
- Taro Kadowaki
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Ryuta Nagayama
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Jens Georg
- University of Freiburg, Institute of Biology III, Schänzlestr. 1, D-79104 Freiburg, Germany
| | - Yoshitaka Nishiyama
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Annegret Wilde
- University of Freiburg, Institute of Biology III, Schänzlestr. 1, D-79104 Freiburg, Germany
| | - Wolfgang R Hess
- University of Freiburg, Institute of Biology III, Schänzlestr. 1, D-79104 Freiburg, Germany
| | - Yukako Hihara
- Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
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11
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Kadowaki T, Nishiyama Y, Hisabori T, Hihara Y. Correction: identification of OmpR-family response regulators interacting with thioredoxin in the cyanobacterium Synechocystis sp. PCC 6803. PLoS One 2015; 10:e0124571. [PMID: 25875789 PMCID: PMC4395214 DOI: 10.1371/journal.pone.0124571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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