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Sato M, Kawaguchi T, Maeda K, Watanabe M, Ikeuchi M, Narikawa R, Watanabe S. Functional Modification of Cyanobacterial Phycobiliprotein and Phycobilisomes through Bilin Metabolism Control. ACS Synth Biol 2024. [PMID: 39038807 DOI: 10.1021/acssynbio.4c00094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Phycobilisomes (PBSs) are light-harvesting antenna complexes in cyanobacteria that adapt to diverse light environments through the use of phycobiliproteins within the PBS structures. Freshwater cyanobacteria, such as Synechococcus elongatus PCC 7942, thrive under red light because of the presence of phycocyanin (PC) and its chromophore, phycocyanobilin (PCB), in the PBS. Cyanobacteria in shorter-wavelength light environments such as green light, employ phycoerythrin paired with phycoerythrobilin (PEB) along with PC in the PBS. Synthetic biology studies have shown that PEB production can be achieved by expression of the heterologous PEB synthases 15,16-dihydrobiliverdin:ferredoxin oxidoreductase (PebA) and PEB:ferredoxin oxidoreductase (PebB), leading to PEB accumulation and cellular browning. This approach is genetically unstable, and the properties of the resulting PEB-bound PBS complexes remain uncharacterized. In this study, we engineered a novel strain of Synechococcus 7942 PEB1 with finely tuned control of PEB biosynthesis. PEB1 exhibited a reversible change in the color of the culture from green to brown and pink based on PebA and PebB induction levels. High induction led to complete PCB-to-PEB substitution, causing the disassembly of the PBS rod complex. In contrast, low induction levels of PebA and PebB resulted in the formation of a stable chimeric PBS complex with partial PCB-to-PEB substitution. This acclimation enabled efficient light harvesting in the green spectrum and energy transfer to the photosynthetic reaction center. These findings, which improve our understanding of PBS and highlight the structural importance of the bilin composition, provide a foundation for future studies on PBS adaptation in bioengineering, synthetic biology, and renewable energy.
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Affiliation(s)
- Mizuho Sato
- Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Takeshi Kawaguchi
- Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Kaisei Maeda
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Mai Watanabe
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Masahiko Ikeuchi
- Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-0041, Japan
| | - Rei Narikawa
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan
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Ohdate K, Sakata M, Maeda K, Sakamaki Y, Nimura-Matsune K, Ohbayashi R, Hess WR, Watanabe S. Discovery of novel replication proteins for large plasmids in cyanobacteria and their potential applications in genetic engineering. Front Microbiol 2024; 15:1311290. [PMID: 38419637 PMCID: PMC10899382 DOI: 10.3389/fmicb.2024.1311290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 01/31/2024] [Indexed: 03/02/2024] Open
Abstract
Numerous cyanobacteria capable of oxygenic photosynthesis possess multiple large plasmids exceeding 100 kbp in size. These plasmids are believed to have distinct replication and distribution mechanisms, as they coexist within cells without causing incompatibilities between plasmids. However, information on plasmid replication proteins (Rep) in cyanobacteria is limited. Synechocystis sp. PCC 6803 hosts four large plasmids, pSYSM, pSYSX, pSYSA, and pSYSG, but Rep proteins for these plasmids, except for CyRepA1 on pSYSA, are unknown. Using Autonomous Replication sequencing (AR-seq), we identified two potential Rep genes in Synechocystis 6803, slr6031 and slr6090, both located on pSYSX. The corresponding Rep candidates, Slr6031 and Slr6090, share structural similarities with Rep-associated proteins of other bacteria and homologs were also identified in various cyanobacteria. We observed autonomous replication activity for Slr6031 and Slr6090 in Synechococcus elongatus PCC 7942 by fusing their genes with a construct expressing GFP and introducing them via transformation. The slr6031/slr6090-containing plasmids exhibited lower copy numbers and instability in Synechococcus 7942 cells compared to the expression vector pYS. While recombination occurred in the case of slr6090, the engineered plasmid with slr6031 coexisted with plasmids encoding CyRepA1 or Slr6090 in Synechococcus 7942 cells, indicating the compatibility of Slr6031 and Slr6090 with CyRepA1. Based on these results, we designated Slr6031 and Slr6090 as CyRepX1 (Cyanobacterial Rep-related protein encoded on pSYSX) and CyRepX2, respectively, demonstrating that pSYSX is a plasmid with "two Reps in one plasmid." Furthermore, we determined the copy number and stability of plasmids with cyanobacterial Reps in Synechococcus 7942 and Synechocystis 6803 to elucidate their potential applications. The novel properties of CyRepX1 and 2, as revealed by this study, hold promise for the development of innovative genetic engineering tools in cyanobacteria.
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Affiliation(s)
- Kazuma Ohdate
- Department of Bioscience, Faculty of Life Science, Tokyo University of Agriculture, Tokyo, Japan
| | - Minori Sakata
- Department of Bioscience, Faculty of Life Science, Tokyo University of Agriculture, Tokyo, Japan
| | - Kaisei Maeda
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Yutaka Sakamaki
- Department of Bioscience, Faculty of Life Science, Tokyo University of Agriculture, Tokyo, Japan
| | - Kaori Nimura-Matsune
- Department of Bioscience, Faculty of Life Science, Tokyo University of Agriculture, Tokyo, Japan
| | - Ryudo Ohbayashi
- Department of Biological Science, Faculty of Science, Shizuoka University, Shizuoka, Japan
| | - Wolfgang R. Hess
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Satoru Watanabe
- Department of Bioscience, Faculty of Life Science, Tokyo University of Agriculture, Tokyo, Japan
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Hidese R, Ohbayashi R, Kato Y, Matsuda M, Tanaka K, Imamura S, Ashida H, Kondo A, Hasunuma T. ppGpp accumulation reduces the expression of the global nitrogen homeostasis-modulating NtcA regulon by affecting 2-oxoglutarate levels. Commun Biol 2023; 6:1285. [PMID: 38145988 PMCID: PMC10749895 DOI: 10.1038/s42003-023-05632-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 11/23/2023] [Indexed: 12/27/2023] Open
Abstract
The cyanobacterium Synechococcus elongatus PCC 7942 accumulates alarmone guanosine tetraphosphate (ppGpp) under stress conditions, such as darkness. A previous study observed that artificial ppGpp accumulation under photosynthetic conditions led to the downregulation of genes involved in the nitrogen assimilation system, which is activated by the global nitrogen regulator NtcA, suggesting that ppGpp regulates NtcA activity. However, the details of this mechanism have not been elucidated. Here, we investigate the metabolic responses associated with ppGpp accumulation by heterologous expression of the ppGpp synthetase RelQ. The pool size of 2-oxoglutarate (2-OG), which activates NtcA, is significantly decreased upon ppGpp accumulation. De novo 13C-labeled CO2 assimilation into the Calvin-Benson-Bassham cycle and glycolytic intermediates continues irrespective of ppGpp accumulation, whereas the labeling of 2-OG is significantly decreased under ppGpp accumulation. The low 2-OG levels in the RelQ overexpression cells could be because of the inhibition of metabolic enzymes, including aconitase, which are responsible for 2-OG biosynthesis. We propose a metabolic rearrangement by ppGpp accumulation, which negatively regulates 2-OG levels to maintain carbon and nitrogen balance.
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Affiliation(s)
- Ryota Hidese
- Graduate School of Science, Innovation and Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Ryudo Ohbayashi
- Laboratory for Chemistry and Life Science Institute of Innovative Research, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
- Department of Biological Sciences, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka, 422-8529, Japan
| | - Yuichi Kato
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Mami Matsuda
- Graduate School of Science, Innovation and Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science Institute of Innovative Research, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science Institute of Innovative Research, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
- NTT Space Environment and Enegy Laboratories, Nippon Telegraph and Telephone Corporation, 3-9-11 Midori-cho, Musashino-shi, Tokyo, 180-8585, Japan
| | - Hiroki Ashida
- Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-Ku, Kobe, 657-8501, Japan
| | - Akihiko Kondo
- Graduate School of Science, Innovation and Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
- Research Center for Sustainable Resource Science, RIKEN, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Tomohisa Hasunuma
- Graduate School of Science, Innovation and Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan.
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan.
- Research Center for Sustainable Resource Science, RIKEN, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan.
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Yoshida R, Ozaki S, Kawakami H, Katayama T. Single-stranded DNA recruitment mechanism in replication origin unwinding by DnaA initiator protein and HU, an evolutionary ubiquitous nucleoid protein. Nucleic Acids Res 2023; 51:6286-6306. [PMID: 37178000 PMCID: PMC10325909 DOI: 10.1093/nar/gkad389] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 04/18/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023] Open
Abstract
The Escherichia coli replication origin oriC contains the initiator ATP-DnaA-Oligomerization Region (DOR) and its flanking duplex unwinding element (DUE). In the Left-DOR subregion, ATP-DnaA forms a pentamer by binding to R1, R5M and three other DnaA boxes. The DNA-bending protein IHF binds sequence-specifically to the interspace between R1 and R5M boxes, promoting DUE unwinding, which is sustained predominantly by binding of R1/R5M-bound DnaAs to the single-stranded DUE (ssDUE). The present study describes DUE unwinding mechanisms promoted by DnaA and IHF-structural homolog HU, a ubiquitous protein in eubacterial species that binds DNA sequence-non-specifically, preferring bent DNA. Similar to IHF, HU promoted DUE unwinding dependent on ssDUE binding of R1/R5M-bound DnaAs. Unlike IHF, HU strictly required R1/R5M-bound DnaAs and interactions between the two DnaAs. Notably, HU site-specifically bound the R1-R5M interspace in a manner stimulated by ATP-DnaA and ssDUE. These findings suggest a model that interactions between the two DnaAs trigger DNA bending within the R1/R5M-interspace and initial DUE unwinding, which promotes site-specific HU binding that stabilizes the overall complex and DUE unwinding. Moreover, HU site-specifically bound the replication origin of the ancestral bacterium Thermotoga maritima depending on the cognate ATP-DnaA. The ssDUE recruitment mechanism could be evolutionarily conserved in eubacteria.
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Affiliation(s)
- Ryusei Yoshida
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Shogo Ozaki
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Hironori Kawakami
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Tsutomu Katayama
- Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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Schvarzstein M, Alam F, Toure M, Yanowitz JL. An Emerging Animal Model for Querying the Role of Whole Genome Duplication in Development, Evolution, and Disease. J Dev Biol 2023; 11:26. [PMID: 37367480 PMCID: PMC10299280 DOI: 10.3390/jdb11020026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 05/23/2023] [Accepted: 06/01/2023] [Indexed: 06/28/2023] Open
Abstract
Whole genome duplication (WGD) or polyploidization can occur at the cellular, tissue, and organismal levels. At the cellular level, tetraploidization has been proposed as a driver of aneuploidy and genome instability and correlates strongly with cancer progression, metastasis, and the development of drug resistance. WGD is also a key developmental strategy for regulating cell size, metabolism, and cellular function. In specific tissues, WGD is involved in normal development (e.g., organogenesis), tissue homeostasis, wound healing, and regeneration. At the organismal level, WGD propels evolutionary processes such as adaptation, speciation, and crop domestication. An essential strategy to further our understanding of the mechanisms promoting WGD and its effects is to compare isogenic strains that differ only in their ploidy. Caenorhabditis elegans (C. elegans) is emerging as an animal model for these comparisons, in part because relatively stable and fertile tetraploid strains can be produced rapidly from nearly any diploid strain. Here, we review the use of Caenorhabditis polyploids as tools to understand important developmental processes (e.g., sex determination, dosage compensation, and allometric relationships) and cellular processes (e.g., cell cycle regulation and chromosome dynamics during meiosis). We also discuss how the unique characteristics of the C. elegans WGD model will enable significant advances in our understanding of the mechanisms of polyploidization and its role in development and disease.
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Affiliation(s)
- Mara Schvarzstein
- Biology Department, Brooklyn College at the City University of New York, Brooklyn, NY 11210, USA
- Biology Department, The Graduate Center at the City University of New York, New York, NY 10016, USA
- Biochemistry Department, The Graduate Center at the City University of New York, New York, NY 10016, USA
| | - Fatema Alam
- Biology Department, Brooklyn College at the City University of New York, Brooklyn, NY 11210, USA
| | - Muhammad Toure
- Biology Department, Brooklyn College at the City University of New York, Brooklyn, NY 11210, USA
| | - Judith L. Yanowitz
- Magee-Womens Research Institute, Pittsburgh, PA 15213, USA;
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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Determinants of Total and Active Microbial Communities Associated with Cyanobacterial Aggregates in a Eutrophic Lake. mSystems 2023; 8:e0099222. [PMID: 36927063 PMCID: PMC10134853 DOI: 10.1128/msystems.00992-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Abstract
Cyanobacterial aggregates (CAs) comprised of photosynthetic and phycospheric microorganisms are often the cause of cyanobacterial blooms in eutrophic freshwater lakes. Although phylogenetic diversity in CAs has been extensively studied, much less was understood about the activity status of microorganisms inside CAs and determinants of their activities. In this study, the 16S rRNA gene (rDNA)-based total communities within CAs in Lake Taihu of China were analyzed over a period of 6 months during the bloom season; the 16S rRNA-based active communities during daytime, nighttime, and under anoxic conditions were also profiled. Synchronous turnover of both cyanobacterial and phycospheric communities was observed, suggesting the presence of close interactions. The rRNA/rDNA ratio-based relative activities of individual taxa were predominantly determined by their rDNA-based relative abundances. In particular, high-abundance taxa demonstrated comparatively lower activities, whereas low-abundance taxa were generally more active. In comparison, hydrophysicochemical factors as well as diurnal and redox conditions showed much less impact on relative activities of microbial taxa within CAs. Nonetheless, total and active communities exhibited differences in community assembly processes, the former of which were almost exclusively controlled by homogeneous selection during daytime and under anoxia. Taken together, the results from this study provide novel insights into the relationships among microbial activities, community structure, and environmental conditions and highlight the importance of further exploring the regulatory mechanisms of microbial activities at the community level. IMPORTANCE Cyanobacterial aggregates are important mediators of biogeochemical cycles in eutrophic lakes during cyanobacterial blooms, yet regulators of microbial activities within them are not well understood. This study revealed rDNA-based abundances strongly affected the relative activities of microbial taxa within Microcystis aggregates, as well as trade-off effects between microbial abundances and activities. Environmental conditions further improved the levels of relative activities and affected community assembly mechanisms in phycospheric communities. The relationships among microbial activities, abundances, and environmental conditions improve our understanding of the regulatory mechanisms of microbial activities in cyanobacterial aggregates and also provide a novel clue for studying determinants of microbial activities in other ecosystems.
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Sakamaki Y, Maeda K, Nimura-Matsune K, Chibazakura T, Watanabe S. Characterization of a cyanobacterial rep protein with broad-host range and its utilization for expression vectors. Front Microbiol 2023; 14:1111979. [PMID: 37032853 PMCID: PMC10079941 DOI: 10.3389/fmicb.2023.1111979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/27/2023] [Indexed: 04/11/2023] Open
Abstract
Owing to their photosynthetic capabilities, cyanobacteria are regarded as ecologically friendly hosts for production of biomaterials. However, compared to other bacteria, tools for genetic engineering, especially expression vector systems, are limited. In this study, we characterized a Rep protein, exhibiting replication activity in multiple cyanobacteria and established an expression vector using this protein. Our comprehensive screening using a genomic library of Synechocystis sp. PCC 6803 revealed that a certain region encoding a Rep-related protein (here named Cyanobacterial Rep protein A2: CyRepA2) exhibits high autonomous replication activity in a heterologous host cyanobacterium, Synechococcus elongatus PCC 7942. A reporter assay using GFP showed that the expression vector pYS carrying CyRepA2 can be maintained in not only S. 6803 and S. 7942, but also Synechococcus sp. PCC 7002 and Anabaena sp. PCC 7120. In S. 7942, GFP expression in the pYS-based system was tightly regulated by IPTG, achieving 10-fold higher levels than in the chromosome-based system. Furthermore, pYS could be used together with the conventional vector pEX, which was constructed from an endogenous plasmid in S. 7942. The combination of pYS with other vectors is useful for genetic engineering, such as modifying metabolic pathways, and is expected to improve the performance of cyanobacteria as bioproduction chassis.
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Affiliation(s)
- Yutaka Sakamaki
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Kaisei Maeda
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | | | - Taku Chibazakura
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
- *Correspondence: Satoru Watanabe,
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Santer M, Kupczok A, Dagan T, Uecker H. Fixation dynamics of beneficial alleles in prokaryotic polyploid chromosomes and plasmids. Genetics 2022; 222:6663764. [PMID: 35959975 PMCID: PMC9526072 DOI: 10.1093/genetics/iyac121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 07/20/2022] [Indexed: 11/15/2022] Open
Abstract
Theoretical population genetics has been mostly developed for sexually reproducing diploid and for monoploid (haploid) organisms, focusing on eukaryotes. The evolution of bacteria and archaea is often studied by models for the allele dynamics in monoploid populations. However, many prokaryotic organisms harbor multicopy replicons—chromosomes and plasmids—and theory for the allele dynamics in populations of polyploid prokaryotes remains lacking. Here, we present a population genetics model for replicons with multiple copies in the cell. Using this model, we characterize the fixation process of a dominant beneficial mutation at 2 levels: the phenotype and the genotype. Our results show that depending on the mode of replication and segregation, the fixation of the mutant phenotype may precede genotypic fixation by many generations; we term this time interval the heterozygosity window. We furthermore derive concise analytical expressions for the occurrence and length of the heterozygosity window, showing that it emerges if the copy number is high and selection strong. Within the heterozygosity window, the population is phenotypically adapted, while both alleles persist in the population. Replicon ploidy thus allows for the maintenance of genetic variation following phenotypic adaptation and consequently for reversibility in adaptation to fluctuating environmental conditions.
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Affiliation(s)
- Mario Santer
- Research group Stochastic Evolutionary Dynamics, Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Anne Kupczok
- Institute of General Microbiology, Kiel University, 24118 Kiel, Germany.,Bioinformatics group, Department of Plant Sciences, Wageningen University & Research, 6708PB Wageningen, Netherlands
| | - Tal Dagan
- Institute of General Microbiology, Kiel University, 24118 Kiel, Germany
| | - Hildegard Uecker
- Research group Stochastic Evolutionary Dynamics, Department of Evolutionary Theory, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
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Synechococcus sp. PCC7002 Uses Peroxiredoxin to Cope with Reactive Sulfur Species Stress. mBio 2022; 13:e0103922. [PMID: 35861504 PMCID: PMC9426444 DOI: 10.1128/mbio.01039-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cyanobacteria are a widely distributed group of microorganisms in the ocean, and they often need to cope with the stress of reactive sulfur species, such as sulfide and sulfane sulfur. Sulfane sulfur refers to the various forms of zero-valent sulfur, including persulfide, polysulfide, and element sulfur (S8). Although sulfane sulfur participates in signaling transduction and resistance to reactive oxygen species in cyanobacteria, it is toxic at high concentrations and induces sulfur stress, which has similar effects to oxidative stress. In this study, we report that Synechococcus sp. PCC7002 uses peroxiredoxin to cope with the stress of cellular sulfane sulfur. Synechococcus sp. PCC7002 contains six peroxiredoxins, and all were induced by S8. Peroxiredoxin I (PrxI) reduced S8 to H2S by forming a disulfide bond between residues Cys53 and Cys153 of the enzyme. A partial deletion strain of Synechococcus sp. PCC7002 with decreased copy numbers of the prxI gene was more sensitive to S8 than was the wild type. Thus, peroxiredoxin is involved in maintaining the homeostasis of cellular sulfane sulfur in cyanobacteria. Given that peroxiredoxin evolved before the occurrence of O2 on Earth, its original function could have been to cope with reactive sulfur species stress, and that function has been preserved. IMPORTANCE Cyanobacteria are the earliest microorganisms that perform oxygenic photosynthesis, which has played a key role in the evolution of life on Earth, and they are the most important primary producers in the modern oceans. The cyanobacterium Synechococcus sp. PCC7002 uses peroxiredoxin to reduce high levels of sulfane sulfur. That function is possibly the original role of peroxiredoxin, as the enzyme evolved before the appearance of O2 on Earth. The preservation of the reduction of sulfane sulfur by peroxiredoxin5-type peroxiredoxins may offer cyanobacteria an advantage in the complex environment of the modern oceans.
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Abstract
Strains of the freshwater cyanobacterium Synechococcus elongatus were first isolated approximately 60 years ago, and PCC 7942 is well established as a model for photosynthesis, circadian biology, and biotechnology research. The recent isolation of UTEX 3055 and subsequent discoveries in biofilm and phototaxis phenotypes suggest that lab strains of S. elongatus are highly domesticated. We performed a comprehensive genome comparison among the available genomes of S. elongatus and sequenced two additional laboratory strains to trace the loss of native phenotypes from the standard lab strains and determine the genetic basis of useful phenotypes. The genome comparison analysis provides a pangenome description of S. elongatus, as well as correction of extensive errors in the published sequence for the type strain PCC 6301. The comparison of gene sets and single nucleotide polymorphisms (SNPs) among strains clarifies strain isolation histories and, together with large-scale genome differences, supports a hypothesis of laboratory domestication. Prophage genes in laboratory strains, but not UTEX 3055, affect pigmentation, while unique genes in UTEX 3055 are necessary for phototaxis. The genomic differences identified in this study include previously reported SNPs that are, in reality, sequencing errors, as well as SNPs and genome differences that have phenotypic consequences. One SNP in the circadian response regulator rpaA that has caused confusion is clarified here as belonging to an aberrant clone of PCC 7942, used for the published genome sequence, that has confounded the interpretation of circadian fitness research.
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Abstract
Disruption of circadian rhythms causes decreased health and fitness, and evidence from multiple organisms links clock disruption to dysregulation of the cell cycle. However, the function of circadian regulation for the essential process of DNA replication remains elusive. Here, we demonstrate that in the cyanobacterium Synechococcus elongatus, a model organism with the simplest known circadian oscillator, the clock generates rhythms in DNA replication to minimize the number of open replication forks near dusk that would have to complete after sunset. Metabolic rhythms generated by the clock ensure that resources are available early at night to support any remaining replication forks. Combining mathematical modeling and experiments, we show that metabolic defects caused by clock-environment misalignment result in premature replisome disassembly and replicative abortion in the dark, leaving cells with incomplete chromosomes that persist through the night. Our study thus demonstrates that a major function of this ancient clock in cyanobacteria is to ensure successful completion of genome replication in a cycling environment.
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Sanz-Luque E, Bhaya D, Grossman AR. Polyphosphate: A Multifunctional Metabolite in Cyanobacteria and Algae. FRONTIERS IN PLANT SCIENCE 2020; 11:938. [PMID: 32670331 PMCID: PMC7332688 DOI: 10.3389/fpls.2020.00938] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/09/2020] [Indexed: 05/19/2023]
Abstract
Polyphosphate (polyP), a polymer of orthophosphate (PO4 3-) of varying lengths, has been identified in all kingdoms of life. It can serve as a source of chemical bond energy (phosphoanhydride bond) that may have been used by biological systems prior to the evolution of ATP. Intracellular polyP is mainly stored as granules in specific vacuoles called acidocalcisomes, and its synthesis and accumulation appear to impact a myriad of cellular functions. It serves as a reservoir for inorganic PO4 3- and an energy source for fueling cellular metabolism, participates in maintaining adenylate and metal cation homeostasis, functions as a scaffold for sequestering cations, exhibits chaperone function, covalently binds to proteins to modify their activity, and enables normal acclimation of cells to stress conditions. PolyP also appears to have a role in symbiotic and parasitic associations, and in higher eukaryotes, low polyP levels seem to impact cancerous proliferation, apoptosis, procoagulant and proinflammatory responses and cause defects in TOR signaling. In this review, we discuss the metabolism, storage, and function of polyP in photosynthetic microbes, which mostly includes research on green algae and cyanobacteria. We focus on factors that impact polyP synthesis, specific enzymes required for its synthesis and degradation, sequestration of polyP in acidocalcisomes, its role in cellular energetics, acclimation processes, and metal homeostasis, and then transition to its potential applications for bioremediation and medical purposes.
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Affiliation(s)
- Emanuel Sanz-Luque
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, United States
- Department of Biochemistry and Molecular Biology, University of Cordoba, Cordoba, Spain
| | - Devaki Bhaya
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, United States
| | - Arthur R. Grossman
- Department of Plant Biology, The Carnegie Institution for Science, Stanford, CA, United States
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Watanabe S, Saito S, Suezaki Y, Seguchi T, Ohbayashi R. Specific binding of DnaA to the DnaA box motif in the cyanobacterium Synechococcus elongatus PCC 7942. J GEN APPL MICROBIOL 2020; 66:80-84. [PMID: 32092716 DOI: 10.2323/jgam.2019.11.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
In bacterial DNA replication, the initiator protein DnaA binds to the multiple DnaA box sequences located at oriC to facilitate the unwinding of duplex DNA strands. The cyanobacterium Synechococcus elongatus PCC 7942, which contains multiple chromosomal copies per cell, has DnaA box (like sequences around the oriC region, which is located upstream of dnaN. We previously observed the binding of DnaA around the oriC region; however, the DNA-binding specificity of DnaA to DnaA box sequences has not been examined. Here, we analyzed the binding specificity of DnaA protein to the DnaA box in S. elongatus by using bio-layer interferometry (BLI), a method for monitoring intermolecular interactions. We observed that recombinant DnaA protein recognized specifically the DnaA box sequence TTTTCCACA in vitro. In addition, DNA binding activity was significantly increased by R328H mutation of DnaA. This is the first report to characterize DnaA binding to the DnaA box sequence in cyanobacteria.
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Affiliation(s)
| | - Shunsuke Saito
- Department of Bioscience, Tokyo University of Agriculture
| | | | | | - Ryudo Ohbayashi
- Department of Gene Function and Phenomics, National Institute of Genetics
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14
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Ohbayashi R, Hirooka S, Onuma R, Kanesaki Y, Hirose Y, Kobayashi Y, Fujiwara T, Furusawa C, Miyagishima SY. Evolutionary Changes in DnaA-Dependent Chromosomal Replication in Cyanobacteria. Front Microbiol 2020; 11:786. [PMID: 32411117 PMCID: PMC7198777 DOI: 10.3389/fmicb.2020.00786] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/02/2020] [Indexed: 12/02/2022] Open
Abstract
Replication of the circular bacterial chromosome is initiated at a unique origin (oriC) in a DnaA-dependent manner in which replication proceeds bidirectionally from oriC to ter. The nucleotide compositions of most bacteria differ between the leading and lagging DNA strands. Thus, the chromosomal DNA sequence typically exhibits an asymmetric GC skew profile. Further, free-living bacteria without genomes encoding dnaA were unknown. Thus, a DnaA-oriC-dependent replication initiation mechanism may be essential for most bacteria. However, most cyanobacterial genomes exhibit irregular GC skew profiles. We previously found that the Synechococcus elongatus chromosome, which exhibits a regular GC skew profile, is replicated in a DnaA-oriC-dependent manner, whereas chromosomes of Synechocystis sp. PCC 6803 and Nostoc sp. PCC 7120, which exhibit an irregular GC skew profile, are replicated from multiple origins in a DnaA-independent manner. Here we investigate the variation in the mechanisms of cyanobacterial chromosome replication. We found that the genomes of certain free-living species do not encode dnaA and such species, including Cyanobacterium aponinum PCC 10605 and Geminocystis sp. NIES-3708, replicate their chromosomes from multiple origins. Synechococcus sp. PCC 7002, which is phylogenetically closely related to dnaA-lacking free-living species as well as to dnaA-encoding but DnaA-oriC-independent Synechocystis sp. PCC 6803, possesses dnaA. In Synechococcus sp. PCC 7002, dnaA was not essential and its chromosomes were replicated from a unique origin in a DnaA-oriC independent manner. Our results also suggest that loss of DnaA-oriC-dependency independently occurred multiple times during cyanobacterial evolution and raises a possibility that the loss of dnaA or loss of DnaA-oriC dependency correlated with an increase in ploidy level.
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Affiliation(s)
- Ryudo Ohbayashi
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
| | - Shunsuke Hirooka
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
| | - Ryo Onuma
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
| | - Yu Kanesaki
- Research Institute of Green Science and Technology, Shizuoka University, Shizuoka, Japan
| | - Yuu Hirose
- Department of Applied Chemistry and Life Science, Toyohashi University of Technology, Toyohashi, Japan
| | - Yusuke Kobayashi
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
| | - Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan.,Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Shizuoka, Japan
| | - Chikara Furusawa
- Center for Biosystems Dynamics Research, RIKEN, Osaka, Japan.,Universal Biology Institute, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan.,Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Shizuoka, Japan
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15
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Olina A, Kuzmenko A, Ninova M, Aravin AA, Kulbachinskiy A, Esyunina D. Genome-wide DNA sampling by Ago nuclease from the cyanobacterium Synechococcus elongatus. RNA Biol 2020; 17:677-688. [PMID: 32013676 PMCID: PMC7237159 DOI: 10.1080/15476286.2020.1724716] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 01/03/2020] [Accepted: 01/12/2020] [Indexed: 12/17/2022] Open
Abstract
Members of the conserved Argonaute (Ago) protein family provide defence against invading nucleic acids in eukaryotes in the process of RNA interference. Many prokaryotes also contain Ago proteins that are predicted to be active nucleases; however, their functional activities in host cells remain poorly understood. Here, we characterize the in vitro and in vivo properties of the SeAgo protein from the mesophilic cyanobacterium Synechococcus elongatus. We show that SeAgo is a DNA-guided nuclease preferentially acting on single-stranded DNA targets, with non-specific guide-independent activity observed for double-stranded substrates. The SeAgo gene is steadily expressed in S. elongatus; however, its deletion or overexpression does not change the kinetics of cell growth. When purified from its host cells or from heterologous E. coli, SeAgo is loaded with small guide DNAs whose formation depends on the endonuclease activity of the argonaute protein. SeAgo co-purifies with SSB proteins suggesting that they may also be involved in DNA processing. The SeAgo-associated small DNAs are derived from diverse genomic locations, with certain enrichment for the proposed sites of chromosomal replication initiation and termination, but show no preference for an endogenous plasmid. Therefore, promiscuous genome sampling by SeAgo does not have great effects on cell physiology and plasmid maintenance.
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Affiliation(s)
- Anna Olina
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Anton Kuzmenko
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
| | - Maria Ninova
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Alexei A. Aravin
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | | | - Daria Esyunina
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia
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16
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Suzuki S, Yamada T. Probabilistic model based on circular statistics for quantifying coverage depth dynamics originating from DNA replication. PeerJ 2020; 8:e8722. [PMID: 32257635 PMCID: PMC7104724 DOI: 10.7717/peerj.8722] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/10/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND With the development of DNA sequencing technology, static omics profiling in microbial communities, such as taxonomic and functional gene composition determination, has become possible. Additionally, the recently proposed in situ growth rate estimation method allows the applicable range of current comparative metagenomics to be extended to dynamic profiling. However, with this method, the applicable target range is presently limited. Furthermore, the characteristics of coverage depth during replication have not been sufficiently investigated. RESULTS We developed a probabilistic model that mimics coverage depth dynamics. This statistical model explains the bias that occurs in the coverage depth due to DNA replication and errors that arise from coverage depth observation. Although our method requires a complete genome sequence, it involves a stable to low coverage depth (>0.01×). We also evaluated the estimation using real whole-genome sequence datasets and reproduced the growth dynamics observed in previous studies. By utilizing a circular distribution in the model, our method facilitates the quantification of unmeasured coverage depth features, including peakedness, skewness, and degree of density, around the replication origin. When we applied the model to time-series culture samples, the skewness parameter, which indicates the asymmetry, was stable over time; however, the peakedness and degree of density parameters, which indicate the concentration level at the replication origin, changed dynamically. Furthermore, we demonstrated the activity measurement of multiple replication origins in a single chromosome. CONCLUSIONS We devised a novel framework for quantifying coverage depth dynamics. Our study is expected to serve as a basis for replication activity estimation from a broader perspective using the statistical model.
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Affiliation(s)
- Shinya Suzuki
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro, Tokyo, Japan
| | - Takuji Yamada
- School of Life Science and Technology, Tokyo Institute of Technology, Meguro, Tokyo, Japan
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17
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Abstract
While the model bacteria Escherichia coli and Bacillus subtilis harbor single chromosomes, which is known as monoploidy, some freshwater cyanobacteria contain multiple chromosome copies per cell throughout their cell cycle, which is known as polyploidy. In the model cyanobacteria Synechococcus elongatus PCC 7942 and Synechocystis sp. PCC 6803, chromosome copy number (ploidy) is regulated in response to growth phase and environmental factors. In S. elongatus 7942, chromosome replication is asynchronous both among cells and chromosomes. Comparative analysis of S. elongatus 7942 and S. sp. 6803 revealed a variety of DNA replication mechanisms. In this review, the current knowledge of ploidy and DNA replication mechanisms in cyanobacteria is summarized together with information on the features common with plant chloroplasts. It is worth noting that the occurrence of polyploidy and its regulation are correlated with certain cyanobacterial lifestyles and are shared between some cyanobacteria and chloroplasts. ABBREVIATIONS NGS: next-generation sequencing; Repli-seq: replication sequencing; BrdU: 5-bromo-2'-deoxyuridine; TK: thymidine kinase; GCSI: GC skew index; PET: photosynthetic electron transport; RET: respiration electron transport; Cyt b6f complex: cytochrome b6f complex; PQ: plastoquinone; PC: plastocyanin.
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Affiliation(s)
- Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture , Tokyo, Japan
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18
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Kami S, Tsuchikado R, Nishida H. DNA replication and cell enlargement of Enterococcus faecalis protoplasts. AIMS Microbiol 2020; 5:347-357. [PMID: 31915747 PMCID: PMC6946640 DOI: 10.3934/microbiol.2019.4.347] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 10/23/2019] [Indexed: 11/18/2022] Open
Abstract
Protoplasts of Enterococcus faecalis did not divide but enlarged in Difco Marine Broth containing penicillin. Our previous studies have demonstrated that transcription and translation were essential for bacterial cell enlargement. However, it was uncertain whether replication was also essential. In this study, we measured the amount of DNA in E. faecalis cells during the course of enlargement using quantitative polymerase chain reaction. The growth of normally divided cells (native forms) of E. faecalis exhibited a log phase before 6 h of incubation was reached. Although a difference in quantitation cycle (Cq) values between the replication initiation and termination regions was observed in the log phase, it was not present in the stationary growth phase. On the other hand, the amount of DNA in E. faecalis protoplasts increased during the cell enlargement incubation. The difference of Cq values between the protoplasts at 0 and 96 h of incubation was 8–9, indicating that the DNA amount at 96 h was 200–500 times higher than that at 0 h. The Cq values differed between the replication initiation and termination regions, indicating that the replication level was high. When novobiocin, a DNA replication inhibitor, was added to the medium at 24 h of incubation, DNA replication and cell enlargement were almost stopped. Thus, replication plays an important role in the enlargement of E. faecalis protoplasts.
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Affiliation(s)
- Satoshi Kami
- Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Rintaro Tsuchikado
- Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Hiromi Nishida
- Department of Biotechnology, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
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19
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Miyagishima SY, Era A, Hasunuma T, Matsuda M, Hirooka S, Sumiya N, Kondo A, Fujiwara T. Day/Night Separation of Oxygenic Energy Metabolism and Nuclear DNA Replication in the Unicellular Red Alga Cyanidioschyzon merolae. mBio 2019; 10:e00833-19. [PMID: 31266864 PMCID: PMC6606799 DOI: 10.1128/mbio.00833-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 06/06/2019] [Indexed: 02/06/2023] Open
Abstract
The transition from G1 to S phase and subsequent nuclear DNA replication in the cells of many species of eukaryotic algae occur predominantly during the evening and night in the absence of photosynthesis; however, little is known about how day/night changes in energy metabolism and cell cycle progression are coordinated and about the advantage conferred by the restriction of S phase to the night. Using a synchronous culture of the unicellular red alga Cyanidioschyzon merolae, we found that the levels of photosynthetic and respiratory activities peak during the morning and then decrease toward the evening and night, whereas the pathways for anaerobic consumption of pyruvate, produced by glycolysis, are upregulated during the evening and night as reported recently in the green alga Chlamydomonas reinhardtii Inhibition of photosynthesis by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) largely reduced respiratory activity and the amplitude of the day/night rhythm of respiration, suggesting that the respiratory rhythm depends largely on photosynthetic activity. Even when the timing of G1/S-phase transition was uncoupled from the day/night rhythm by depletion of retinoblastoma-related (RBR) protein, the same patterns of photosynthesis and respiration were observed, suggesting that cell cycle progression and energy metabolism are regulated independently. Progression of the S phase under conditions of photosynthesis elevated the frequency of nuclear DNA double-strand breaks (DSB). These results suggest that the temporal separation of oxygenic energy metabolism, which causes oxidative stress, from nuclear DNA replication reduces the risk of DSB during cell proliferation in C. merolaeIMPORTANCE Eukaryotes acquired chloroplasts through an endosymbiotic event in which a cyanobacterium or a unicellular eukaryotic alga was integrated into a previously nonphotosynthetic eukaryotic cell. Photosynthesis by chloroplasts enabled algae to expand their habitats and led to further evolution of land plants. However, photosynthesis causes greater oxidative stress than mitochondrion-based respiration. In seed plants, cell division is restricted to nonphotosynthetic meristematic tissues and populations of photosynthetic cells expand without cell division. Thus, seemingly, photosynthesis is spatially sequestrated from cell proliferation. In contrast, eukaryotic algae possess photosynthetic chloroplasts throughout their life cycle. Here we show that oxygenic energy conversion (daytime) and nuclear DNA replication (night time) are temporally sequestrated in C. merolae This sequestration enables "safe" proliferation of cells and allows coexistence of chloroplasts and the eukaryotic host cell, as shown in yeast, where mitochondrial respiration and nuclear DNA replication are temporally sequestrated to reduce the mutation rate.
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Affiliation(s)
- Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka, Japan
- JST-Mirai Program, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, Japan
| | - Atsuko Era
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Tomohisa Hasunuma
- Graduate School of Science, Technology and Innovation, Kobe University, Nada, Kobe, Japan
- Engineering Biology Research Center, Kobe University, Nada, Kobe, Japan
| | - Mami Matsuda
- Engineering Biology Research Center, Kobe University, Nada, Kobe, Japan
| | - Shunsuke Hirooka
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka, Japan
- JST-Mirai Program, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
| | - Nobuko Sumiya
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Akihiko Kondo
- Graduate School of Science, Technology and Innovation, Kobe University, Nada, Kobe, Japan
- Engineering Biology Research Center, Kobe University, Nada, Kobe, Japan
- Biomass Engineering Program, RIKEN, Yokohama, Kanagawa, Japan
| | - Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Mishima, Shizuoka, Japan
- JST-Mirai Program, Japan Science and Technology Agency, Kawaguchi, Saitama, Japan
- Department of Genetics, Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka, Japan
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20
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Werner A, Broeckling CD, Prasad A, Peebles CAM. A comprehensive time-course metabolite profiling of the model cyanobacterium Synechocystis sp. PCC 6803 under diurnal light:dark cycles. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 99:379-388. [PMID: 30889309 DOI: 10.1111/tpj.14320] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 03/06/2019] [Accepted: 03/12/2019] [Indexed: 05/07/2023]
Abstract
Cyanobacteria are a model photoautotroph and a chassis for the sustainable production of fuels and chemicals. Knowledge of photoautotrophic metabolism in the natural environment of day/night cycles is lacking, yet has implications for improved yield from plants, algae and cyanobacteria. Here, a thorough approach to characterizing diverse metabolites-including carbohydrates, lipids, amino acids, pigments, cofactors, nucleic acids and polysaccharides-in the model cyanobacterium Synechocystis sp. PCC 6803 (S. 6803) under sinusoidal diurnal light:dark cycles was developed and applied. A custom photobioreactor and multi-platform mass spectrometry workflow enabled metabolite profiling every 30-120 min across a 24-h diurnal sinusoidal LD ('sinLD') cycle peaking at 1600 μmol photons m-2 sec-1 . We report widespread oscillations across the sinLD cycle with 90%, 94% and 40% of the identified polar/semi-polar, non-polar and polymeric metabolites displaying statistically significant oscillations, respectively. Microbial growth displayed distinct lag, biomass accumulation and cell division phases of growth. During the lag phase, amino acids and nucleic acids accumulated to high levels per cell followed by decreased levels during the biomass accumulation phase, presumably due to protein and DNA synthesis. Insoluble carbohydrates displayed sharp oscillations per cell at the day-to-night transition. Potential bottlenecks in central carbon metabolism are highlighted. Together, this report provides a comprehensive view of photosynthetic metabolite behavior with high temporal resolution, offering insight into the impact of growth synchronization to light cycles via circadian rhythms. Incorporation into computational modeling and metabolic engineering efforts promises to improve industrially relevant strain design.
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Affiliation(s)
- Allison Werner
- Cell and Molecular Biology Program, Colorado State University, 1005 Campus Delivery, Fort Collins, CO, 80523, USA
| | - Corey D Broeckling
- Proteomics and Metabolomics Facility, Colorado State University, 2021 Campus Delivery, Fort Collins, CO, 80523, USA
| | - Ashok Prasad
- Cell and Molecular Biology Program, Colorado State University, 1005 Campus Delivery, Fort Collins, CO, 80523, USA
- Department of Chemical and Biological Engineering, Colorado State University, 1370 Campus Delivery, Fort Collins, CO, 80523, USA
| | - Christie A M Peebles
- Cell and Molecular Biology Program, Colorado State University, 1005 Campus Delivery, Fort Collins, CO, 80523, USA
- Department of Chemical and Biological Engineering, Colorado State University, 1370 Campus Delivery, Fort Collins, CO, 80523, USA
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21
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Gärtner K, Klähn S, Watanabe S, Mikkat S, Scholz I, Hess WR, Hagemann M. Cytosine N4-Methylation via M.Ssp6803II Is Involved in the Regulation of Transcription, Fine- Tuning of DNA Replication and DNA Repair in the Cyanobacterium Synechocystis sp. PCC 6803. Front Microbiol 2019; 10:1233. [PMID: 31231331 PMCID: PMC6560206 DOI: 10.3389/fmicb.2019.01233] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/17/2019] [Indexed: 12/15/2022] Open
Abstract
DNA methylation plays a crucial role for gene regulation among eukaryotes, but its regulatory function is less documented in bacteria. In the cyanobacterium Synechocystis sp. PCC 6803 five DNA methyltransferases have been identified. Among them, M.Ssp6803II is responsible for the specific methylation of the first cytosine in the frequently occurring motif GGCC, leading to N4-methylcytosine (GGm4CC). The mutation of the corresponding gene sll0729 led to lowered chlorophyll/phycocyanin ratio and slower growth. Transcriptomics only showed altered expression of sll0470 and sll1526, two genes encoding hypothetical proteins. Moreover, prolonged cultivation revealed instability of the initially obtained phenotype. Colonies with normal pigmentation and wild-type-like growth regularly appeared on agar plates. These colonies represent suppressor mutants, because the sll0729 gene was still completely inactivated and the GGCC sites remained unmethylated. The suppressor strains showed smaller cell size, lowered DNA content per cell, and decreased tolerance against UV compared to wild type. Promoter assays revealed that the transcription of the sll0470 gene was still stimulated in the suppressor clones. Proteomics identified decreased levels of DNA topoisomerase 4 subunit A in suppressor cells. Collectively, these results indicate that GGm4CC methylation is involved in the regulation of gene expression, in the fine-tuning of DNA replication, and DNA repair mechanisms.
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Affiliation(s)
- Katrin Gärtner
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Stephan Klähn
- Faculty of Biology, Genetics & Experimental Bioinformatics, University of Freiburg, Freiburg im Breisgau, Germany
- Department of Solar Materials, Helmholtz-Centre for Environmental Research, Leipzig, Germany
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Stefan Mikkat
- Core Facility Proteome Analysis, University Medicine Rostock, Rostock, Germany
| | - Ingeborg Scholz
- Faculty of Biology, Genetics & Experimental Bioinformatics, University of Freiburg, Freiburg im Breisgau, Germany
| | - Wolfgang R. Hess
- Faculty of Biology, Genetics & Experimental Bioinformatics, University of Freiburg, Freiburg im Breisgau, Germany
- Freiburg Institute for Advanced Studies, University of Freiburg, Freiburg im Breisgau, Germany
| | - Martin Hagemann
- Department of Plant Physiology, University of Rostock, Rostock, Germany
- Department Life, Light and Matter, University of Rostock, Rostock, Germany
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22
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Reyes-Lamothe R, Sherratt DJ. The bacterial cell cycle, chromosome inheritance and cell growth. Nat Rev Microbiol 2019; 17:467-478. [DOI: 10.1038/s41579-019-0212-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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23
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Abstract
Polyploidy has evolved many times across the kingdom of life. The relationship between cell growth and chromosome replication in bacteria has been studied extensively in monoploid model organisms such as Escherichia coli but not in polyploid organisms. Our study of the polyploid cyanobacterium Synechococcus elongatus demonstrates that replicating chromosome number is restricted and regulated by DnaA to maintain a relatively stable gene copy number/cell volume ratio during cell growth. In addition, our results suggest that polyploidy confers resistance to UV, which damages DNA. This compensatory polyploidy is likely necessitated by photosynthesis, which requires sunlight and generates damaging reactive oxygen species, and may also explain how polyploid bacteria can adapt to extreme environments with high risk of DNA damage. Homologous chromosome number (ploidy) has diversified among bacteria, archaea, and eukaryotes over evolution. In bacteria, model organisms such as Escherichia coli possess a single chromosome encoding the entire genome during slow growth. In contrast, other bacteria, including cyanobacteria, maintain multiple copies of individual chromosomes (polyploid). Although a correlation between ploidy level and cell size has been observed in bacteria and eukaryotes, it is poorly understood how replication of multicopy chromosomes is regulated and how ploidy level is adjusted to cell size. In addition, the advantages conferred by polyploidy are largely unknown. Here we show that only one or a few multicopy chromosomes are replicated at once in the cyanobacterium Synechococcus elongatus and that this restriction depends on regulation of DnaA activity. Inhibiting the DnaA intrinsic ATPase activity in S. elongatus increased the number of replicating chromosomes and chromosome number per cell but did not affect cell growth. In contrast, when cell growth rate was increased or decreased, DnaA level, DnaA activity, and the number of replicating chromosomes also increased or decreased in parallel, resulting in nearly constant chromosome copy number per unit of cell volume at constant temperature. When chromosome copy number was increased by inhibition of DnaA ATPase activity or reduced culture temperature, cells exhibited greater resistance to UV light. Thus, it is suggested that the stepwise replication of the genome enables cyanobacteria to maintain nearly constant gene copy number per unit of cell volume and that multicopy chromosomes function as backup genetic information to compensate for genomic damage.
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24
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Welkie DG, Rubin BE, Diamond S, Hood RD, Savage DF, Golden SS. A Hard Day's Night: Cyanobacteria in Diel Cycles. Trends Microbiol 2019; 27:231-242. [PMID: 30527541 PMCID: PMC6377297 DOI: 10.1016/j.tim.2018.11.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 11/01/2018] [Accepted: 11/02/2018] [Indexed: 12/31/2022]
Abstract
Cyanobacteria are photosynthetic prokaryotes that are influential in global geochemistry and are promising candidates for industrial applications. Because the livelihood of cyanobacteria is directly dependent upon light, a comprehensive understanding of metabolism in these organisms requires taking into account the effects of day-night transitions and circadian regulation. These events synchronize intracellular processes with the solar day. Accordingly, metabolism is controlled and structured differently in cyanobacteria than in heterotrophic bacteria. Thus, the approaches applied to engineering heterotrophic bacteria will need to be revised for the cyanobacterial chassis. Here, we summarize important findings related to diurnal metabolism in cyanobacteria and present open questions in the field.
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Affiliation(s)
- David G Welkie
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Benjamin E Rubin
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Spencer Diamond
- Department of Earth and Planetary Science, UC Berkeley, Berkeley, CA 94720, USA
| | - Rachel D Hood
- Department of Molecular and Cell Biology, UC Berkeley, Berkeley, CA 94720, USA
| | - David F Savage
- Department of Molecular and Cell Biology, UC Berkeley, Berkeley, CA 94720, USA
| | - Susan S Golden
- Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093, USA; Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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25
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Motomura K, Sano K, Watanabe S, Kanbara A, Gamal Nasser AH, Ikeda T, Ishida T, Funabashi H, Kuroda A, Hirota R. Synthetic Phosphorus Metabolic Pathway for Biosafety and Contamination Management of Cyanobacterial Cultivation. ACS Synth Biol 2018; 7:2189-2198. [PMID: 30203964 DOI: 10.1021/acssynbio.8b00199] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent progress in genetic engineering and synthetic biology have greatly expanded the production capabilities of cyanobacteria, but concerns regarding biosafety issues and the risk of contamination of cultures in outdoor culture conditions remain to be resolved. With this dual goal in mind, we applied the recently established biological containment strategy based on phosphite (H3PO3, Pt) dependency to the model cyanobacterium Synechococcus elongatus PCC 7942 ( Syn 7942). Pt assimilation capability was conferred on Syn 7942 by the introduction of Pt dehydrogenase (PtxD) and hypophosphite transporter (HtxBCDE) genes that allow the uptake of Pt, but not phosphate (H3PO4, Pi). We then identified and disrupted the two indigenous Pi transporters, pst (Synpcc7942_2441 to 2445) and pit (Synpcc7942_0184). The resultant strain failed to grow on any media containing various types of P compounds other than Pt. The strain did not yield any escape mutants for at least 28 days with a detection limit of 3.6 × 10-11 per colony forming unit, and rapidly lost viability in the absence of Pt. Moreover, growth competition of the Pt-dependent strain with wild-type cyanobacteria revealed that the Pt-dependent strain could dominate in cultures containing Pt as the sole P source. Because Pt is rarely available in aquatic environments this strategy can contribute to both biosafety and contamination management of genetically engineered cyanobacteria.
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Affiliation(s)
- Kei Motomura
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
| | - Kosuke Sano
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Satoru Watanabe
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
- Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Akihiro Kanbara
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Abdel-Hady Gamal Nasser
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Takeshi Ikeda
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Takenori Ishida
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Hisakage Funabashi
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
| | - Akio Kuroda
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
| | - Ryuichi Hirota
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST-ALCA), Chiyoda-ku, Tokyo 102-0076, Japan
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26
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Ohbayashi R, Yoshikawa H, Watanabe S. Direct Visualization of the Multicopy Chromosomes in Cyanobacterium Synechococcus elongatus PCC 7942. Bio Protoc 2018; 8:e2958. [PMID: 34395766 DOI: 10.21769/bioprotoc.2958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 07/16/2018] [Accepted: 07/31/2018] [Indexed: 11/02/2022] Open
Abstract
Cyanobacteria are prokaryotic organisms that carry out oxygenic photosynthesis. The fresh water cyanobacterium Synechococcus elongatus PCC 7942 is a model organism for the study of photosynthesis and gene regulation, and for biotechnological applications. Besides several freshwater cyanobacteria, S. elongatus 7942 also contains multiple chromosomal copies per cell at all stages of its cell cycle. Here, we describe a method for the direct visualization of multicopy chromosomes in S. elongatus 7942 by fluorescence in situ hybridization (FISH).
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Affiliation(s)
- Ryudo Ohbayashi
- Department of Cell Genetics, National Institute of Genetics, Shizuoka, Japan
| | - Hirofumi Yoshikawa
- Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo, Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo, Japan
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27
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Jun S, Si F, Pugatch R, Scott M. Fundamental principles in bacterial physiology-history, recent progress, and the future with focus on cell size control: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:056601. [PMID: 29313526 PMCID: PMC5897229 DOI: 10.1088/1361-6633/aaa628] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Bacterial physiology is a branch of biology that aims to understand overarching principles of cellular reproduction. Many important issues in bacterial physiology are inherently quantitative, and major contributors to the field have often brought together tools and ways of thinking from multiple disciplines. This article presents a comprehensive overview of major ideas and approaches developed since the early 20th century for anyone who is interested in the fundamental problems in bacterial physiology. This article is divided into two parts. In the first part (sections 1-3), we review the first 'golden era' of bacterial physiology from the 1940s to early 1970s and provide a complete list of major references from that period. In the second part (sections 4-7), we explain how the pioneering work from the first golden era has influenced various rediscoveries of general quantitative principles and significant further development in modern bacterial physiology. Specifically, section 4 presents the history and current progress of the 'adder' principle of cell size homeostasis. Section 5 discusses the implications of coarse-graining the cellular protein composition, and how the coarse-grained proteome 'sectors' re-balance under different growth conditions. Section 6 focuses on physiological invariants, and explains how they are the key to understanding the coordination between growth and the cell cycle underlying cell size control in steady-state growth. Section 7 overviews how the temporal organization of all the internal processes enables balanced growth. In the final section 8, we conclude by discussing the remaining challenges for the future in the field.
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Affiliation(s)
- Suckjoon Jun
- Department of Physics, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, United States of America. Section of Molecular Biology, Division of Biology, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, United States of America
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28
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Luo H, Quan CL, Peng C, Gao F. Recent development of Ori-Finder system and DoriC database for microbial replication origins. Brief Bioinform 2018; 20:1114-1124. [DOI: 10.1093/bib/bbx174] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 12/04/2017] [Indexed: 01/28/2023] Open
Abstract
Abstract
DNA replication begins at replication origins in all three domains of life. Identification and characterization of replication origins are important not only in providing insights into the structure and function of the replication origins but also in understanding the regulatory mechanisms of the initiation step in DNA replication. The Z-curve method has been used in the identification of replication origins in archaeal genomes successfully since 2002. Furthermore, the Web servers of Ori-Finder and Ori-Finder 2 have been developed to predict replication origins in both bacterial and archaeal genomes based on the Z-curve method, and the replication origins with manual curation have been collected into an online database, DoriC. Ori-Finder system and DoriC database are currently used in the research field of DNA replication origins in prokaryotes, including: (i) identification of oriC regions in bacterial and archaeal genomes; (ii) discovery and analysis of the conserved sequences within oriC regions; and (iii) strand-biased analysis of bacterial genomes.
Up to now, more and more predicted results by Ori-Finder system were supported by subsequent experiments, and Ori-Finder system has been used to identify the replication origins in > 100 newly sequenced prokaryotes in their genome reports. In addition, the data in DoriC database have been widely used in the large-scale analyses of replication origins and strand bias in prokaryotic genomes. Here, we review the development of Ori-Finder system and DoriC database as well as their applications. Some future directions and aspects for extending the application of Ori-Finder and DoriC are also presented.
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29
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Watanabe S, Ozawa H, Kato H, Nimura-Matsune K, Hirayama T, Kudo F, Eguchi T, Kakinuma K, Yoshikawa H. Carbon-free production of 2-deoxy-scyllo-inosose (DOI) in cyanobacterium Synechococcus elongatus PCC 7942. Biosci Biotechnol Biochem 2018; 82:161-165. [PMID: 29297252 DOI: 10.1080/09168451.2017.1411777] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Owing to their photosynthetic capabilities, there is increasing interest in utilizing cyanobacteria to convert solar energy into biomass. 2-Deoxy-scyllo-inosose (DOI) is a valuable starting material for the benzene-free synthesis of catechol and other benzenoids. DOI synthase (DOIS) is responsible for the formation of DOI from d-glucose-6-phosphate (G6P) in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics such as neomycin and butirosin. DOI fermentation using a recombinant Escherichia coli strain has been reported, although a carbon source is necessary for high-yield DOI production. We constructed DOI-producing cyanobacteria toward carbon-free and sustainable DOI production. A DOIS gene derived from the butirosin producer strain Bacillus circulans (btrC) was introduced and expressed in the cyanobacterium Synechococcus elongatus PCC 7942. We ultimately succeeded in producing 400 mg/L of DOI in S. elongatus without using a carbon source. DOI production by cyanobacteria represents a novel and efficient approach for producing benzenoids from G6P synthesized by photosynthesis.
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Affiliation(s)
- Satoru Watanabe
- a Department of Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | - Hiroaki Ozawa
- a Department of Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | - Hiroaki Kato
- a Department of Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | | | - Toshifumi Hirayama
- b Department of Chemistry , Tokyo Institute of Technology , Tokyo , Japan
| | - Fumitaka Kudo
- b Department of Chemistry , Tokyo Institute of Technology , Tokyo , Japan
| | - Tadashi Eguchi
- b Department of Chemistry , Tokyo Institute of Technology , Tokyo , Japan
| | - Katsumi Kakinuma
- b Department of Chemistry , Tokyo Institute of Technology , Tokyo , Japan
| | - Hirofumi Yoshikawa
- a Department of Bioscience , Tokyo University of Agriculture , Tokyo , Japan
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30
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Shimakawa G, Watanabe S, Miyake C. A Carbon Dioxide Limitation-Inducible Protein, ColA, Supports the Growth of Synechococcus sp. PCC 7002. Mar Drugs 2017; 15:md15120390. [PMID: 29244744 PMCID: PMC5742850 DOI: 10.3390/md15120390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/30/2017] [Accepted: 12/09/2017] [Indexed: 11/16/2022] Open
Abstract
A limitation in carbon dioxide (CO₂), which occurs as a result of natural environmental variation, suppresses photosynthesis and has the potential to cause photo-oxidative damage to photosynthetic cells. Oxygenic phototrophs have strategies to alleviate photo-oxidative damage to allow life in present atmospheric CO₂ conditions. However, the mechanisms for CO₂ limitation acclimation are diverse among the various oxygenic phototrophs, and many mechanisms remain to be discovered. In this study, we found that the gene encoding a CO₂ limitation-inducible protein, ColA, is required for the cyanobacterium Synechococcus sp. PCC 7002 (S. 7002) to acclimate to limited CO₂ conditions. An S. 7002 mutant deficient in ColA (ΔcolA) showed lower chlorophyll content, based on the amount of nitrogen, than that in S. 7002 wild-type (WT) under ambient air but not high CO₂ conditions. Both thermoluminescence and protein carbonylation detected in the ambient air grown cells indicated that the lack of ColA promotes oxidative stress in S. 7002. Alterations in the photosynthetic O₂ evolution rate and relative electron transport rate in the short-term response, within an hour, to CO₂ limitation were the same between the WT and ΔcolA. Conversely, these photosynthetic parameters were mostly lower in the long-term response of a few days in ΔcolA than in the WT. These data suggest that ColA is required to sustain photosynthetic activity for living under ambient air in S. 7002. The unique phylogeny of ColA revealed diverse strategies to acclimate to CO₂ limitation among cyanobacteria.
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Affiliation(s)
- Ginga Shimakawa
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan.
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan.
| | - Chikahiro Miyake
- Department of Biological and Environmental Science, Faculty of Agriculture, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe 657-8501, Japan.
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31
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Watanabe S, Noda A, Ohbayashi R, Uchioke K, Kurihara A, Nakatake S, Morioka S, Kanesaki Y, Chibazakura T, Yoshikawa H. ParA-like protein influences the distribution of multi-copy chromosomes in cyanobacterium Synechococcus elongatus PCC 7942. MICROBIOLOGY-SGM 2017; 164:45-56. [PMID: 29165230 DOI: 10.1099/mic.0.000577] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
While many bacteria, such as Escherichia coli and Bacillus subtilis, harbour a single-copy chromosome, freshwater cyanobacteria have multiple copies of each chromosome per cell. Although it has been reported that multi-copy chromosomes are evenly distributed along the major axis of the cell in cyanobacterium Synechococcus elongatus PCC 7942, the distribution mechanism of these chromosomes remains unclear. In S. elongatus, the carboxysome, a metabolic microcompartment for carbon fixation that is distributed in a similar manner to the multi-copy chromosomes, is regulated by ParA-like protein (hereafter ParA). To elucidate the role of ParA in the distribution of multi-copy chromosomes, we constructed and analysed ParA disruptant and overexpressing strains of S. elongatus. Our fluorescence in situ hybridization assay revealed that the parA disruptants displayed an aberrant distribution of their multi-copy chromosomes. In the parA disruptant the multiple origin and terminus foci, corresponding to the intracellular position of each chromosomal region, were aggregated, which was compensated by the expression of exogenous ParA from other genomic loci. The parA disruptant is sensitive to UV-C compared to the WT strain. Additionally, giant cells appeared under ParA overexpression at the late stage of growth indicating that excess ParA indirectly inhibits cell division. Screening of the ParA-interacting proteins by yeast two-hybrid analysis revealed four candidates that are involved in DNA repair and cell membrane biogenesis. These results suggest that ParA is involved in the pleiotropic cellular functions with these proteins, while parA is dispensable for cell viability in S. elongatus.
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Affiliation(s)
- Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Aska Noda
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Ryudo Ohbayashi
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Japan.,Department of Cell Genetics, National Institute of Genetics, Shizuoka, 411-8540, Japan
| | - Kana Uchioke
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Ami Kurihara
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Shizuka Nakatake
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Sayumi Morioka
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Yu Kanesaki
- Genome Research Center, Tokyo University of Agriculture, Tokyo, Japan
| | - Taku Chibazakura
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Hirofumi Yoshikawa
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Japan
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32
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Jun S, Rust MJ. A Fundamental Unit of Cell Size in Bacteria. Trends Genet 2017; 33:433-435. [PMID: 28545962 DOI: 10.1016/j.tig.2017.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 05/08/2017] [Indexed: 10/19/2022]
Abstract
A new study clarifies a relationship between growth, gene expression, and cell size in cyanobacteria. Quite unexpectedly, cyanobacteria and Escherichia coli appear to share an invariance principle to coordinate growth and chromosome replication. This principle allows quantitative predictions of cell size across a range of growth conditions in both organisms.
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Affiliation(s)
- Suckjoon Jun
- University of California San Diego, Department of Physics and Section of Molecular Biology, Division of Biology, 9500 Gilman Drive, La Jolla, CA 92093, USA.
| | - Michael J Rust
- University of Chicago, Department of Molecular Genetics and Cell Biology, Department of Physics, 900 E 57th St., Chicago, IL 60637, USA.
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33
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Zheng XY, O'Shea EK. Cyanobacteria Maintain Constant Protein Concentration despite Genome Copy-Number Variation. Cell Rep 2017; 19:497-504. [PMID: 28423314 DOI: 10.1016/j.celrep.2017.03.067] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 11/25/2022] Open
Abstract
The cyanobacterium Synechococcus elongatus PCC 7942 has multiple copies of its single chromosome, and the copy number varies in individual cells, providing an ideal system to study the effect of genome copy-number variation on cell size and gene expression. Using single-cell fluorescence imaging, we found that protein concentration remained constant across individual cells regardless of genome copy number. Cell volume and the total protein amount from a single gene were both positively, linearly correlated with genome copy number, suggesting that changes in cell volume play an important role in buffering genome copy-number variance. This study provides a quantitative examination of gene expression regulation in cells with variable genome copies and sheds light on the compensation mechanisms for variance in genome copy number.
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Affiliation(s)
- Xiao-Yu Zheng
- Howard Hughes Medical Institute, Harvard University Faculty of Arts and Sciences Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Erin K O'Shea
- Howard Hughes Medical Institute, Harvard University Faculty of Arts and Sciences Center for Systems Biology, Harvard University, Cambridge, MA 02138, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA.
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34
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Kobayashi I, Watanabe S, Kanesaki Y, Shimada T, Yoshikawa H, Tanaka K. Conserved two-component Hik34-Rre1 module directly activates heat-stress inducible transcription of major chaperone and other genes in Synechococcus elongatus PCC 7942. Mol Microbiol 2017; 104:260-277. [PMID: 28106321 DOI: 10.1111/mmi.13624] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2017] [Indexed: 11/28/2022]
Abstract
Bacteria and other organisms, including cyanobacteria, employ two-component signal transducing modules comprising histidine kinases and response regulators to acclimate to changing environments. While the number and composition of these modules differ among cyanobacteria, two response regulators that contain DNA binding domains, RpaB and Rre1, are conserved in all sequenced cyanobacterial genomes and are essential for viability. Although RpaB negatively or positively regulates high light and other stress-responsive gene expression, little is known about the function of Rre1. Here, they investigated the direct regulatory targets of Rre1 in the cyanobacterium Synechococcus elongatus PCC 7942. Chromatin immunoprecipitation and high-density tiling array analysis were used to map Rre1 binding sites. The sites included promoter regions for chaperone genes such as dnaK2, groESL-1, groEL-2, hspA and htpG, as well as the group 2 sigma factor gene rpoD2. In vivo and in vitro analyses revealed that Rre1 phosphorylation level, DNA binding activity and adjacent gene transcription increased in response to heat stress. These responses were much diminished in a knock-out mutant of Hik34, a previously identified heat shock regulator. Based on our results, we propose Hik34-Rre1 is the heat shock-responsive signaling module that positively regulates major chaperone and other genes in cyanobacteria.
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Affiliation(s)
- Ikki Kobayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.,Graduate School of Interdisciplinary Science, Tokyo Institute of Technology, Nagatsuta 4259-R1-29, Midori-ku, Yokohama, 226-8503, Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Yu Kanesaki
- NODAI Genome Research Center, Tokyo University of Agriculture, Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Tomohiro Shimada
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan
| | - Hirofumi Yoshikawa
- Department of Bioscience, Tokyo University of Agriculture, Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
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35
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Ohbayashi R, Yamamoto JY, Watanabe S, Kanesaki Y, Chibazakura T, Miyagishima SY, Yoshikawa H. Variety of DNA Replication Activity Among Cyanobacteria Correlates with Distinct Respiration Activity in the Dark. PLANT & CELL PHYSIOLOGY 2017; 58:279-286. [PMID: 27837093 DOI: 10.1093/pcp/pcw186] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 10/28/2016] [Indexed: 06/06/2023]
Abstract
Cyanobacteria exhibit light-dependent cell growth since most of their cellular energy is obtained by photosynthesis. In Synechococcus elongatus PCC 7942, one of the model cyanobacteria, DNA replication depends on photosynthetic electron transport. However, the critical signal for the regulatory mechanism of DNA replication has not been identified. In addition, conservation of this regulatory mechanism has not been investigated among cyanobacteria. To understand this regulatory signal and its dependence on light, we examined the regulation of DNA replication under both light and dark conditions among three model cyanobacteria, S. elongatus PCC 7942, Synechocystis sp. PCC 6803 and Anabaena sp. PCC 7120. Interestingly, DNA replication activity in Synechocystis and Anabaena was retained when cells were transferred to the dark, although it was drastically decreased in S. elongatus. Glycogen metabolism and respiration were higher in Synechocystis and Anabaena than in S. elongatus in the dark. Moreover, DNA replication activity in Synechocystis and Anabaena was reduced to the same level as that in S. elongatus by inhibition of respiratory electron transport after transfer to the dark. These results demonstrate that there is disparity in DNA replication occurring in the dark among cyanobacteria, which is caused by the difference in activity of respiratory electron transport.
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Affiliation(s)
- Ryudo Ohbayashi
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
- Department of Cell Genetics, National Institute of Genetics, Shizuoka, Japan
| | - Jun-Ya Yamamoto
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Yu Kanesaki
- Genome Research Center, Tokyo University of Agriculture, Tokyo, Japan
| | - Taku Chibazakura
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Shin-Ya Miyagishima
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
- Department of Cell Genetics, National Institute of Genetics, Shizuoka, Japan
| | - Hirofumi Yoshikawa
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
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36
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Klotz A, Georg J, Bučinská L, Watanabe S, Reimann V, Januszewski W, Sobotka R, Jendrossek D, Hess W, Forchhammer K. Awakening of a Dormant Cyanobacterium from Nitrogen Chlorosis Reveals a Genetically Determined Program. Curr Biol 2016; 26:2862-2872. [DOI: 10.1016/j.cub.2016.08.054] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/09/2016] [Accepted: 08/22/2016] [Indexed: 01/09/2023]
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37
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Tashiro M, Kiyota H, Kawai-Noma S, Saito K, Ikeuchi M, Iijima Y, Umeno D. Bacterial Production of Pinene by a Laboratory-Evolved Pinene-Synthase. ACS Synth Biol 2016; 5:1011-20. [PMID: 27247193 DOI: 10.1021/acssynbio.6b00140] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Successful feeding of the substrate geranylpyrophosphate (GPP) to monoterpene synthase is critical to the efficient microbial production of monoterpenes. Overexpression of GPP synthases, metabolic channeling from GPP synthase to terpene synthases, and down-tuning of endogenous competitors have been successfully used to increase the production of monoterpene. Nevertheless, the production of monoterpenes has remained considerably lower than that of hemi-/sesqui-terpenoids. We tested whether it is effective to improve the cellular activity of monoterpene synthases. To this end, we developed a high-throughput screening system to monitor for elevated GPP consumption. Through a single round of mutagenesis and screening, we isolated a pinene synthase variant that outperformed the wild-type (parent) enzyme in multiple contexts in Escherichia coli and cyanobacteria. The purified variant exhibited drastically altered metal dependency, enabling to keep the activity in the cytosol that is manganese-deficient. Coexpression of this variant with mevalonate pathway enzymes, isopentenylpyrophosphate isomerase, and GPP synthase yielded 140 mg/L pinene in a flask culture.
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Affiliation(s)
- Miki Tashiro
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
| | - Hiroshi Kiyota
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shigeko Kawai-Noma
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
| | - Kyoichi Saito
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
| | - Masahiko Ikeuchi
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Department of Life
Sciences (Biology), Graduate School of Arts and Science, University of Tokyo, 3-8-1 Meguro-ku, Tokyo 153-8902, Japan
| | - Yoko Iijima
- Department of Nutrition
and Life Science, Kanagawa Institute of Technology, 1030 Shimo-ogino, Atsugi, Kanagawa 243-0292, Japan
| | - Daisuke Umeno
- Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University, 1-33 Yayoi-Cyo, Inage-ku, Chiba 263-8522, Japan
- Precursory Research
for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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The bacterial DnaA-trio replication origin element specifies single-stranded DNA initiator binding. Nature 2016; 534:412-6. [PMID: 27281207 PMCID: PMC4913881 DOI: 10.1038/nature17962] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 03/30/2016] [Indexed: 12/30/2022]
Abstract
DNA replication is tightly controlled to ensure accurate inheritance of genetic information. In all organisms, initiator proteins possessing AAA+ (ATPases associated with various cellular activities) domains bind replication origins to license new rounds of DNA synthesis. In bacteria the master initiator protein, DnaA, is highly conserved and has two crucial DNA binding activities. DnaA monomers recognize the replication origin (oriC) by binding double-stranded DNA sequences (DnaA-boxes); subsequently, DnaA filaments assemble and promote duplex unwinding by engaging and stretching a single DNA strand. While the specificity for duplex DnaA-boxes by DnaA has been appreciated for over 30 years, the sequence specificity for single-strand DNA binding has remained unknown. Here we identify a new indispensable bacterial replication origin element composed of a repeating trinucleotide motif that we term the DnaA-trio. We show that the function of the DnaA-trio is to stabilize DnaA filaments on a single DNA strand, thus providing essential precision to this binding mechanism. Bioinformatic analysis detects DnaA-trios in replication origins throughout the bacterial kingdom, indicating that this element is part of the core oriC structure. The discovery and characterization of the novel DnaA-trio extends our fundamental understanding of bacterial DNA replication initiation, and because of the conserved structure of AAA+ initiator proteins these findings raise the possibility of specific recognition motifs within replication origins of higher organisms.
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Zerulla K, Ludt K, Soppa J. The ploidy level of Synechocystis sp. PCC 6803 is highly variable and is influenced by growth phase and by chemical and physical external parameters. Microbiology (Reading) 2016; 162:730-739. [DOI: 10.1099/mic.0.000264] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Karolin Zerulla
- Institute for Molecular Biosciences, Biocentre, Goethe-University,Frankfurt,Germany
| | - Katharina Ludt
- Institute for Molecular Biosciences, Biocentre, Goethe-University,Frankfurt,Germany
| | - Jörg Soppa
- Institute for Molecular Biosciences, Biocentre, Goethe-University,Frankfurt,Germany
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40
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Discrete gene replication events drive coupling between the cell cycle and circadian clocks. Proc Natl Acad Sci U S A 2016; 113:4063-8. [PMID: 27035936 DOI: 10.1073/pnas.1507291113] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Many organisms possess both a cell cycle to control DNA replication and a circadian clock to anticipate changes between day and night. In some cases, these two rhythmic systems are known to be coupled by specific, cross-regulatory interactions. Here, we use mathematical modeling to show that, additionally, the cell cycle generically influences circadian clocks in a nonspecific fashion: The regular, discrete jumps in gene-copy number arising from DNA replication during the cell cycle cause a periodic driving of the circadian clock, which can dramatically alter its behavior and impair its function. A clock built on negative transcriptional feedback either phase-locks to the cell cycle, so that the clock period tracks the cell division time, or exhibits erratic behavior. We argue that the cyanobacterium Synechococcus elongatus has evolved two features that protect its clock from such disturbances, both of which are needed to fully insulate it from the cell cycle and give it its observed robustness: a phosphorylation-based protein modification oscillator, together with its accompanying push-pull read-out circuit that responds primarily to the ratios of different phosphoform concentrations, makes the clock less susceptible to perturbations in protein synthesis; the presence of multiple, asynchronously replicating copies of the same chromosome diminishes the effect of replicating any single copy of a gene.
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41
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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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42
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Diversification of DnaA dependency for DNA replication in cyanobacterial evolution. ISME JOURNAL 2015; 10:1113-21. [PMID: 26517699 DOI: 10.1038/ismej.2015.194] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 09/01/2015] [Accepted: 09/27/2015] [Indexed: 11/08/2022]
Abstract
Regulating DNA replication is essential for all living cells. The DNA replication initiation factor DnaA is highly conserved in prokaryotes and is required for accurate initiation of chromosomal replication at oriC. DnaA-independent free-living bacteria have not been identified. The dnaA gene is absent in plastids and some symbiotic bacteria, although it is not known when or how DnaA-independent mechanisms were acquired. Here, we show that the degree of dependency of DNA replication on DnaA varies among cyanobacterial species. Deletion of the dnaA gene in Synechococcus elongatus PCC 7942 shifted DNA replication from oriC to a different site as a result of the integration of an episomal plasmid. Moreover, viability during the stationary phase was higher in dnaA disruptants than in wild-type cells. Deletion of dnaA did not affect DNA replication or cell growth in Synechocystis sp. PCC 6803 or Anabaena sp. PCC 7120, indicating that functional dependency on DnaA was already lost in some nonsymbiotic cyanobacterial lineages during diversification. Therefore, we proposed that cyanobacteria acquired DnaA-independent replication mechanisms before symbiosis and such an ancestral cyanobacterium was the sole primary endosymbiont to form a plastid precursor.
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43
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Yokoo R, Hood RD, Savage DF. Live-cell imaging of cyanobacteria. PHOTOSYNTHESIS RESEARCH 2015; 126:33-46. [PMID: 25366827 DOI: 10.1007/s11120-014-0049-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 10/14/2014] [Indexed: 06/04/2023]
Abstract
Cyanobacteria are a diverse bacterial phylum whose members possess a high degree of ultrastructural organization and unique gene regulatory mechanisms. Unraveling this complexity will require the use of live-cell fluorescence microscopy, but is impeded by the inherent fluorescent background associated with light-harvesting pigments and the need to feed photosynthetic cells light. Here, we outline a roadmap for overcoming these challenges. Specifically, we show that although basic cyanobacterial biology creates challenging experimental constraints, these restrictions can be mitigated by the careful choice of fluorophores and microscope instrumentation. Many of these choices are motivated by recent successful live-cell studies. We therefore also highlight how live-cell imaging has advanced our understanding of bacterial microcompartments, circadian rhythm, and the organization and segregation of the bacterial nucleoid.
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Affiliation(s)
- Rayka Yokoo
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - Rachel D Hood
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - David F Savage
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA, 94720, USA.
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA.
- Energy Biosciences Institute, University of California, Berkeley, Berkeley, CA, 94720, USA.
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44
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Watanabe S, Ohbayashi R, Kanesaki Y, Saito N, Chibazakura T, Soga T, Yoshikawa H. Intensive DNA Replication and Metabolism during the Lag Phase in Cyanobacteria. PLoS One 2015; 10:e0136800. [PMID: 26331851 PMCID: PMC4558043 DOI: 10.1371/journal.pone.0136800] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 08/07/2015] [Indexed: 12/20/2022] Open
Abstract
Unlike bacteria such as Escherichia coli and Bacillus subtilis, several species of freshwater cyanobacteria are known to contain multiple chromosomal copies per cell, at all stages of their cell cycle. We have characterized the replication of multi-copy chromosomes in the cyanobacterium Synechococcus elongatus PCC 7942 (hereafter Synechococcus 7942). In Synechococcus 7942, the replication of multi-copy chromosome is asynchronous, not only among cells but also among multi-copy chromosomes. This suggests that DNA replication is not tightly coupled to cell division in Synechococcus 7942. To address this hypothesis, we analysed the relationship between DNA replication and cell doubling at various growth phases of Synechococcus 7942 cell culture. Three distinct growth phases were characterised in Synechococcus 7942 batch culture: lag phase, exponential phase, and arithmetic (linear) phase. The chromosomal copy number was significantly higher during the lag phase than during the exponential and linear phases. Likewise, DNA replication activity was higher in the lag phase cells than in the exponential and linear phase cells, and the lag phase cells were more sensitive to nalidixic acid, a DNA gyrase inhibitor, than cells in other growth phases. To elucidate physiological differences in Synechococcus 7942 during the lag phase, we analysed the metabolome at each growth phase. In addition, we assessed the accumulation of central carbon metabolites, amino acids, and DNA precursors at each phase. The results of these analyses suggest that Synechococcus 7942 cells prepare for cell division during the lag phase by initiating intensive chromosomal DNA replication and accumulating metabolites necessary for the subsequent cell division and elongation steps that occur during the exponential growth and linear phases.
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Affiliation(s)
- Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Ryudo Ohbayashi
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
| | - Yu Kanesaki
- Genome Research Center, Tokyo University of Agriculture, Tokyo, Japan
| | - Natsumi Saito
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Taku Chibazakura
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Tomoyoshi Soga
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, Japan
| | - Hirofumi Yoshikawa
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
- * E-mail:
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45
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Kiyota H, Okuda Y, Ito M, Hirai MY, Ikeuchi M. Engineering of cyanobacteria for the photosynthetic production of limonene from CO2. J Biotechnol 2014; 185:1-7. [DOI: 10.1016/j.jbiotec.2014.05.025] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 05/23/2014] [Accepted: 05/26/2014] [Indexed: 10/25/2022]
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46
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Abstract
A periodic bias in nucleotide frequency with a period of about 11 bp is characteristic for bacterial genomes. This signal is commonly interpreted to relate to the helical pitch of negatively supercoiled DNA. Functions in supercoiling-dependent RNA transcription or as a 'structural code' for DNA packaging have been suggested. Cyanobacterial genomes showed especially strong periodic signals and, on the other hand, DNA supercoiling and supercoiling-dependent transcription are highly dynamic and underlie circadian rhythms of these phototrophic bacteria. Focusing on this phylum and dinucleotides, we find that a minimal motif of AT-tracts (AT2) yields the strongest signal. Strong genome-wide periodicity is ancestral to a clade of unicellular and polyploid species but lost upon morphological transitions into two baeocyte-forming and a symbiotic species. The signal is intermediate in heterocystous species and weak in monoploid picocyanobacteria. A pronounced 'structural code' may support efficient nucleoid condensation and segregation in polyploid cells. The major source of the AT2 signal are protein-coding regions, where it is encoded preferentially in the first and third codon positions. The signal shows only few relations to supercoiling-dependent and diurnal RNA transcription in Synechocystis sp. PCC 6803. Strong and specific signals in two distinct transposons suggest roles in transposase transcription and transpososome formation.
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Affiliation(s)
- Robert Lehmann
- Institute for Theoretical Biology, Humboldt University, Berlin, Invalidenstraße 43, D-10115, Berlin, Germany
| | - Rainer Machné
- Institute for Theoretical Biology, Humboldt University, Berlin, Invalidenstraße 43, D-10115, Berlin, Germany Institute for Theoretical Chemistry, University of Vienna, Währinger Straße 17, A-1090, Vienna, Austria
| | - Hanspeter Herzel
- Institute for Theoretical Biology, Humboldt University, Berlin, Invalidenstraße 43, D-10115, Berlin, Germany
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47
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Gao F. Recent Advances in the Identification of Replication Origins Based on the Z-curve Method. Curr Genomics 2014; 15:104-12. [PMID: 24822028 PMCID: PMC4009838 DOI: 10.2174/1389202915999140328162938] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 11/04/2013] [Accepted: 11/05/2013] [Indexed: 12/19/2022] Open
Abstract
Precise DNA replication is critical for the maintenance of genetic integrity in all organisms. In all three domains
of life, DNA replication starts at a specialized locus, termed as the replication origin, oriC or ORI, and its identification
is vital to understanding the complex replication process. In bacteria and eukaryotes, replication initiates from single
and multiple origins, respectively, while archaea can adopt either of the two modes. The Z-curve method has been
successfully used to identify replication origins in genomes of various species, including multiple oriCs in some archaea.
Based on the Z-curve method and comparative genomics analysis, we have developed a web-based system, Ori-Finder, for
finding oriCs in bacterial genomes with high accuracy. Predicted oriC regions in bacterial genomes are organized into an
online database, DoriC. Recently, archaeal oriC regions identified by both in vivo and in silico methods have also been included
in the database. Here, we summarize the recent advances of in silico prediction of oriCs in bacterial and archaeal
genomes using the Z-curve based method.
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Affiliation(s)
- Feng Gao
- Department of Physics, Tianjin University, Tianjin 300072, China
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48
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Moriyama T, Sato N. Enzymes involved in organellar DNA replication in photosynthetic eukaryotes. FRONTIERS IN PLANT SCIENCE 2014; 5:480. [PMID: 25278952 PMCID: PMC4166229 DOI: 10.3389/fpls.2014.00480] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 08/30/2014] [Indexed: 05/18/2023]
Abstract
Plastids and mitochondria possess their own genomes. Although the replication mechanisms of these organellar genomes remain unclear in photosynthetic eukaryotes, several organelle-localized enzymes related to genome replication, including DNA polymerase, DNA primase, DNA helicase, DNA topoisomerase, single-stranded DNA maintenance protein, DNA ligase, primer removal enzyme, and several DNA recombination-related enzymes, have been identified. In the reference Eudicot plant Arabidopsis thaliana, the replication-related enzymes of plastids and mitochondria are similar because many of them are dual targeted to both organelles, whereas in the red alga Cyanidioschyzon merolae, plastids and mitochondria contain different replication machinery components. The enzymes involved in organellar genome replication in green plants and red algae were derived from different origins, including proteobacterial, cyanobacterial, and eukaryotic lineages. In the present review, we summarize the available data for enzymes related to organellar genome replication in green plants and red algae. In addition, based on the type and distribution of replication enzymes in photosynthetic eukaryotes, we discuss the transitional history of replication enzymes in the organelles of plants.
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Affiliation(s)
- Takashi Moriyama
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
- Japan Science and Technology Agency – Core Research for Evolutional Science and TechnologyTokyo, Japan
| | - Naoki Sato
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of TokyoTokyo, Japan
- Japan Science and Technology Agency – Core Research for Evolutional Science and TechnologyTokyo, Japan
- *Correspondence: Naoki Sato, Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan e-mail:
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49
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Ohbayashi R, Watanabe S, Kanesaki Y, Narikawa R, Chibazakura T, Ikeuchi M, Yoshikawa H. DNA replication depends on photosynthetic electron transport in cyanobacteria. FEMS Microbiol Lett 2013; 344:138-44. [PMID: 23621483 DOI: 10.1111/1574-6968.12166] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 04/24/2013] [Indexed: 11/28/2022] Open
Abstract
The freshwater cyanobacterium Synechococcus elongatus PCC 7942 exhibits light-dependent growth. Although it has been reported that DNA replication also depends on light irradiation in S. elongatus 7942, the involvement of the light in the regulation of DNA replication remains unclear. To elucidate the regulatory pathway of DNA replication by light, we studied the effect of several inhibitors, including two electron transport inhibitors, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone (DBMIB), on DNA replication in S. elongatus 7942. DCMU inhibited only DNA replication initiation, whereas DBMIB blocked both the initiation and progression of DNA replication. These results suggest that DNA replication depends on the photosynthetic electron transport activity and initiation and progression of DNA replication are regulated in different ways.
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Affiliation(s)
- Ryudo Ohbayashi
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
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50
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Chen AH, Afonso B, Silver PA, Savage DF. Spatial and temporal organization of chromosome duplication and segregation in the cyanobacterium Synechococcus elongatus PCC 7942. PLoS One 2012; 7:e47837. [PMID: 23112856 PMCID: PMC3480399 DOI: 10.1371/journal.pone.0047837] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 09/21/2012] [Indexed: 01/02/2023] Open
Abstract
The spatial and temporal control of chromosome duplication and segregation is crucial for proper cell division. While this process is well studied in eukaryotic and some prokaryotic organisms, relatively little is known about it in prokaryotic polyploids such as Synechococcus elongatus PCC 7942, which is known to possess one to eight copies of its single chromosome. Using a fluorescent repressor-operator system, S. elongatus chromosomes and chromosome replication forks were tagged and visualized. We found that chromosomal duplication is asynchronous and that the total number of chromosomes is correlated with cell length. Thus, replication is independent of cell cycle and coupled to cell growth. Replication events occur in a spatially random fashion. However, once assembled, replisomes move in a constrained manner. On the other hand, we found that segregation displays a striking spatial organization in some cells. Chromosomes transiently align along the major axis of the cell and timing of alignment was correlated to cell division. This mechanism likely contributes to the non-random segregation of chromosome copies to daughter cells.
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Affiliation(s)
- Anna H. Chen
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bruno Afonso
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Pamela A. Silver
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, United States of America
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts, United States of America
| | - David F. Savage
- Department of Molecular and Cell Biology and Department of Chemistry, University of California, Berkeley, California, United States of America
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