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Bilger R, Migur A, Wulf A, Steglich C, Urlaub H, Hess WR. A type III-Dv CRISPR-Cas system is controlled by the transcription factor RpaB and interacts with the DEAD-box RNA helicase CrhR. Cell Rep 2024; 43:114485. [PMID: 38996066 DOI: 10.1016/j.celrep.2024.114485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 05/26/2024] [Accepted: 06/25/2024] [Indexed: 07/14/2024] Open
Abstract
How CRISPR-Cas systems defend bacteria and archaea against invading genetic elements is well understood, but less is known about their regulation. In the cyanobacterium Synechocystis sp. PCC 6803, the expression of one of the three different CRISPR-Cas systems responds to changes in environmental conditions. The cas operon promoter of this system is controlled by the light- and redox-responsive transcription factor RpaB binding to an HLR1 motif, resulting in transcriptional activation at low light intensities. However, the strong promoter that drives transcription of the cognate repeat-spacer array is not controlled by RpaB. Instead, the leader transcript is bound by the redox-sensitive RNA helicase CrhR. Crosslinking coupled with mass spectrometry analysis and site-directed mutagenesis revealed six residues involved in the CrhR-RNA interaction, with C371 being critically important. Thus, the expression of a type III-Dv CRISPR-Cas system is linked to the redox status of the photosynthetic cell at the transcriptional and post-transcriptional levels.
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Affiliation(s)
- Raphael Bilger
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Angela Migur
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Alexander Wulf
- Bioanalytics Research Group, Department of Clinical Chemistry, University Medical Centre, 37075 Göttingen, Germany; Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Claudia Steglich
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Henning Urlaub
- Bioanalytics Research Group, Department of Clinical Chemistry, University Medical Centre, 37075 Göttingen, Germany; Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Wolfgang R Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany.
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2
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Hu WF, Yang JY, Wang JJ, Yuan SF, Yue XJ, Zhang Z, Zhang YQ, Meng JY, Li YZ. Characteristics and immune functions of the endogenous CRISPR-Cas systems in myxobacteria. mSystems 2024; 9:e0121023. [PMID: 38747603 PMCID: PMC11237760 DOI: 10.1128/msystems.01210-23] [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: 11/13/2023] [Accepted: 04/15/2024] [Indexed: 06/19/2024] Open
Abstract
The clustered regularly interspaced short palindromic repeats and their associated proteins (CRISPR-Cas) system widely occurs in prokaryotic organisms to recognize and destruct genetic invaders. Systematic collation and characterization of endogenous CRISPR-Cas systems are conducive to our understanding and potential utilization of this natural genetic machinery. In this study, we screened 39 complete and 692 incomplete genomes of myxobacteria using a combined strategy to dispose of the abridged genome information and revealed at least 19 CRISPR-Cas subtypes, which were distributed with a taxonomic difference and often lost stochastically in intraspecies strains. The cas genes in each subtype were evolutionarily clustered but deeply separated, while most of the CRISPRs were divided into four types based on the motif characteristics of repeat sequences. The spacers recorded in myxobacterial CRISPRs were in high G+C content, matching lots of phages, tiny amounts of plasmids, and, surprisingly, massive organismic genomes. We experimentally demonstrated the immune and self-target immune activities of three endogenous systems in Myxococcus xanthus DK1622 against artificial genetic invaders and revealed the microhomology-mediated end-joining mechanism for the immunity-induced DNA repair but not homology-directed repair. The panoramic view and immune activities imply potential omnipotent immune functions and applications of the endogenous CRISPR-Cas machinery. IMPORTANCE Serving as an adaptive immune system, clustered regularly interspaced short palindromic repeats and their associated proteins (CRISPR-Cas) empower prokaryotes to fend off the intrusion of external genetic materials. Myxobacteria are a collective of swarming Gram-stain-negative predatory bacteria distinguished by intricate multicellular social behavior. An in-depth analysis of their intrinsic CRISPR-Cas systems is beneficial for our understanding of the survival strategies employed by host cells within their environmental niches. Moreover, the experimental findings presented in this study not only suggest the robust immune functions of CRISPR-Cas in myxobacteria but also their potential applications.
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Affiliation(s)
- Wei-Feng Hu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Jiang-Yu Yang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Jing-Jing Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Shu-Fei Yuan
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Xin-Jing Yue
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Zheng Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Ya-Qi Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Jun-Yan Meng
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Yue-Zhong Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
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Yang H, Patel DJ. Structures, mechanisms and applications of RNA-centric CRISPR-Cas13. Nat Chem Biol 2024; 20:673-688. [PMID: 38702571 PMCID: PMC11375968 DOI: 10.1038/s41589-024-01593-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 02/27/2024] [Indexed: 05/06/2024]
Abstract
Prokaryotes are equipped with a variety of resistance strategies to survive frequent viral attacks or invading mobile genetic elements. Among these, CRISPR-Cas surveillance systems are abundant and have been studied extensively. This Review focuses on CRISPR-Cas type VI Cas13 systems that use single-subunit RNA-guided Cas endonucleases for targeting and subsequent degradation of foreign RNA, thereby providing adaptive immunity. Notably, distinct from single-subunit DNA-cleaving Cas9 and Cas12 systems, Cas13 exhibits target RNA-activated substrate RNase activity. This Review outlines structural, biochemical and cell biological studies toward elucidation of the unique structural and mechanistic principles underlying surveillance effector complex formation, precursor CRISPR RNA (pre-crRNA) processing, self-discrimination and RNA degradation in Cas13 systems as well as insights into suppression by bacteriophage-encoded anti-CRISPR proteins and regulation by endogenous accessory proteins. Owing to its programmable ability for RNA recognition and cleavage, Cas13 provides powerful RNA targeting, editing, detection and imaging platforms with emerging biotechnological and therapeutic applications.
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Affiliation(s)
- Hui Yang
- Key Laboratory of RNA Innovation, Science and Engineering, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.
| | - Dinshaw J Patel
- Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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4
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Schumacher MA, Cannistraci E, Salinas R, Lloyd D, Messner E, Gozzi K. Structure of the WYL-domain containing transcription activator, DriD, in complex with ssDNA effector and DNA target site. Nucleic Acids Res 2024; 52:1435-1449. [PMID: 38142455 PMCID: PMC10853764 DOI: 10.1093/nar/gkad1198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/20/2023] [Accepted: 12/01/2023] [Indexed: 12/26/2023] Open
Abstract
Transcription regulators play central roles in orchestrating responses to changing environmental conditions. Recently the Caulobacter crescentus transcription activator DriD, which belongs to the newly defined WYL-domain family, was shown to regulate DNA damage responses independent of the canonical SOS pathway. However, the molecular mechanisms by which DriD and other WYL-regulators sense environmental signals and recognize DNA are not well understood. We showed DriD DNA-binding is triggered by its interaction with ssDNA, which is produced during DNA damage. Here we describe the structure of the full-length C. crescentus DriD bound to both target DNA and effector ssDNA. DriD consists of an N-terminal winged-HTH (wHTH) domain, linker region, three-helix bundle, WYL-domain and C-terminal WCX-dimer domain. Strikingly, DriD binds DNA using a novel, asymmetric DNA-binding mechanism that results from different conformations adopted by the linker. Although the linker does not touch DNA, our data show that contacts it makes with the wHTH are key for specific DNA binding. The structure indicates how ssDNA-effector binding to the WYL-domain impacts wHTH DNA binding. In conclusion, we present the first structure of a WYL-activator bound to both effector and target DNA. The structure unveils a unique, asymmetric DNA binding mode that is likely conserved among WYL-activators.
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Affiliation(s)
- Maria A Schumacher
- Department of Biochemistry, 307 Research Dr., Box 3711, Duke University Medical Center, Durham, NC 27710, USA
| | - Emily Cannistraci
- Department of Biochemistry, 307 Research Dr., Box 3711, Duke University Medical Center, Durham, NC 27710, USA
| | - Raul Salinas
- Department of Biochemistry, 307 Research Dr., Box 3711, Duke University Medical Center, Durham, NC 27710, USA
| | - Devin Lloyd
- 100 Edwin H Land Blvd, Rowland Institute at Harvard, Harvard University, Cambridge, Cambridge, MA 02142, USA
| | - Ella Messner
- 100 Edwin H Land Blvd, Rowland Institute at Harvard, Harvard University, Cambridge, Cambridge, MA 02142, USA
| | - Kevin Gozzi
- 100 Edwin H Land Blvd, Rowland Institute at Harvard, Harvard University, Cambridge, Cambridge, MA 02142, USA
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Tang J, Hu Z, Zhang J, Daroch M. Genome-scale identification and comparative analysis of transcription factors in thermophilic cyanobacteria. BMC Genomics 2024; 25:44. [PMID: 38195395 PMCID: PMC10775510 DOI: 10.1186/s12864-024-09969-7] [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: 07/13/2023] [Accepted: 01/03/2024] [Indexed: 01/11/2024] Open
Abstract
BACKGROUND The transcription factors (TFs) in thermophilic cyanobacteria might represent a uniquely evolved gene repertoire in light of the strong selective pressure caused by hostile habitats. Understanding the molecular composition of the TF genes in thermophilic cyanobacteria will facilitate further studies regarding verifying their exact biochemical functions and genetic engineering. However, limited information is available on the TFs of thermophilic cyanobacteria. Herein, a thorough investigation and comparative analysis were performed to gain insights into the molecular composition of the TFs in 22 thermophilic cyanobacteria. RESULTS The results suggested a fascinating diversity of the TFs among these thermophiles. The abundance and type of TF genes were diversified in these genomes. The identified TFs are speculated to play various roles in biological regulations. Further comparative and evolutionary genomic analyses revealed that HGT may be associated with the genomic plasticity of TF genes in Thermostichus and Thermosynechococcus strains. Comparative analyses also indicated different pattern of TF composition between thermophiles and corresponding mesophilic reference cyanobacteria. Moreover, the identified unique TFs of thermophiles are putatively involved in various biological regulations, mainly as responses to ambient changes, may facilitating the thermophiles to survive in hot springs. CONCLUSION The findings herein shed light on the TFs of thermophilic cyanobacteria and fundamental knowledge for further research regarding thermophilic cyanobacteria with a broad potential for transcription regulations in responses to environmental fluctuations.
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Affiliation(s)
- Jie Tang
- School of Pharmacy and Bioengineering, Chengdu University, Chengdu, 610106, China
| | - Zhe Hu
- School of Pharmacy and Bioengineering, Chengdu University, Chengdu, 610106, China
| | - Jing Zhang
- Food Safety Detection Key Laboratory of Sichuan, Technical Center of Chengdu Customs, Chengdu, 610041, China.
| | - Maurycy Daroch
- School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
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Keller LML, Flattich K, Weber-Ban E. Novel WYL domain-containing transcriptional activator acts in response to genotoxic stress in rapidly growing mycobacteria. Commun Biol 2023; 6:1222. [PMID: 38042942 PMCID: PMC10693628 DOI: 10.1038/s42003-023-05592-6] [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: 07/05/2023] [Accepted: 11/15/2023] [Indexed: 12/04/2023] Open
Abstract
The WYL domain is a nucleotide-sensing module that controls the activity of transcription factors involved in the regulation of DNA damage response and phage defense mechanisms in bacteria. In this study, we investigated a WYL domain-containing transcription factor in Mycobacterium smegmatis that we termed stress-involved WYL domain-containing regulator (SiwR). We found that SiwR controls adjacent genes that belong to the DinB/YfiT-like putative metalloenzymes superfamily by upregulating their expression in response to various genotoxic stress conditions, including upon exposure to H2O2 or the natural antibiotic zeocin. We show that SiwR binds different forms of single-stranded DNA (ssDNA) with high affinity, primarily through its characteristic WYL domain. In combination with complementation studies of a M. smegmatis siwR deletion strain, our findings support a role of the WYL domains as signal-sensing activity switches of WYL domain-containing transcription factors (WYL TFs). Our study provides evidence that WYL TFs are involved in the adaptation of bacteria to changing environments and encountered stress conditions.
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Affiliation(s)
| | - Kim Flattich
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093, Zurich, Switzerland
| | - Eilika Weber-Ban
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093, Zurich, Switzerland.
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7
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Basu S, Bhattacharya D, Pramanik A, Saha M, Mukherjee J. In-silico whole-genome sequence analysis of a halotolerant filamentous mangrove cyanobacterium revealed CRISPR-Cas systems with unique properties. JOURNAL OF PHYCOLOGY 2023; 59:1339-1346. [PMID: 37795780 DOI: 10.1111/jpy.13393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 09/07/2023] [Indexed: 10/06/2023]
Abstract
Novel CRISPR systems capable of cleaving both DNA and RNA are progressively emerging as attractive tools for genome manipulation of prokaryotic and eukaryotic organisms. We report specific characteristics of CRISPR systems present in Oxynema aestuarii AP17, a halotolerant, filamentous cyanobacterium and the second known member of the Oxynema genus. In-silico analyses of its whole-genome sequence revealed the presence of multiple Type I and Type III CRISPR loci with one Type I-G system previously unreported in cyanobacteria. We further identified the leader sequences at the 5' end of multiple CRISPR loci, many of which were distinct from previously reported cyanobacterial CRISPR leaders. Phylogenetic analyses of the O. aestuarii AP17 Cas1 proteins revealed two protein sequences that were unique and distantly related to other cyanobacterial Cas1 protein sequences. Our findings are significant because novel Class 1 CRISPR systems possess multi-subunit effectors and are highly flexible for repurposing by protein domain fusions made to the effector complex. Additionally, Type III CRISPRs are particularly useful for genome editing in certain extremophiles for which mesophilic Type II CRISPRs are ineffective.
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Affiliation(s)
- Shayontani Basu
- School of Environmental Studies, Jadavpur University, Kolkata, India
| | | | - Arnab Pramanik
- Jagadis Bose National Science Talent Search, Kolkata, India
| | - Malay Saha
- Department of Botany, Sovarani Memorial College, Howrah, India
| | - Joydeep Mukherjee
- School of Environmental Studies, Jadavpur University, Kolkata, India
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8
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McBride TM, Cameron SC, Fineran PC, Fagerlund RD. The biology and type I/III hybrid nature of type I-D CRISPR-Cas systems. Biochem J 2023; 480:471-488. [PMID: 37052300 PMCID: PMC10212523 DOI: 10.1042/bcj20220073] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 04/14/2023]
Abstract
Prokaryotes have adaptive defence mechanisms that protect them from mobile genetic elements and viral infection. One defence mechanism is called CRISPR-Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins). There are six different types of CRISPR-Cas systems and multiple subtypes that vary in composition and mode of action. Type I and III CRISPR-Cas systems utilise multi-protein complexes, which differ in structure, nucleic acid binding and cleaving preference. The type I-D system is a chimera of type I and III systems. Recently, there has been a burst of research on the type I-D CRISPR-Cas system. Here, we review the mechanism, evolution and biotechnological applications of the type I-D CRISPR-Cas system.
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Affiliation(s)
- Tess M. McBride
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
| | - Shaharn C. Cameron
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Peter C. Fineran
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Robert D. Fagerlund
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, PO Box 56, Dunedin 9054, New Zealand
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9
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Keller LM, Weber-Ban E. An emerging class of nucleic acid-sensing regulators in bacteria: WYL domain-containing proteins. Curr Opin Microbiol 2023; 74:102296. [PMID: 37027901 DOI: 10.1016/j.mib.2023.102296] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 04/09/2023]
Abstract
Transcriptional regulation plays a central role in adaptation to changing environments for all living organisms. Recently, proteins belonging to a novel widespread class of bacterial transcription factors have been characterized in mycobacteria and Proteobacteria. Those multidomain proteins carry a WYL domain that is almost exclusive to the domain of bacteria. WYL domain-containing proteins act as regulators in different cellular contexts, including the DNA damage response and bacterial immunity. WYL domains have an Sm-like fold with five antiparallel β-strands arranged into a β-sandwich preceded by an α-helix. A common feature of WYL domains is their ability to bind nucleic acids that regulate their activity. In this review, we discuss recent progress made toward the understanding of WYL domain-containing proteins as transcriptional regulators, their structural features, and molecular mechanisms, as well as their functional roles in bacterial physiology.
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Affiliation(s)
- Lena Ml Keller
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland
| | - Eilika Weber-Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
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10
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Watanabe S, Stazic D, Georg J, Ohtake S, Sakamaki Y, Numakura M, Asayama M, Chibazakura T, Wilde A, Steglich C, Hess WR. Regulation of RNase E during the UV stress response in the cyanobacterium Synechocystis sp. PCC 6803. MLIFE 2023; 2:43-57. [PMID: 38818332 PMCID: PMC10989929 DOI: 10.1002/mlf2.12056] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 12/07/2022] [Accepted: 12/15/2022] [Indexed: 06/01/2024]
Abstract
Endoribonucleases govern the maturation and degradation of RNA and are indispensable in the posttranscriptional regulation of gene expression. A key endoribonuclease in Gram-negative bacteria is RNase E. To ensure an appropriate supply of RNase E, some bacteria, such as Escherichia coli, feedback-regulate RNase E expression via the rne 5'-untranslated region (5' UTR) in cis. However, the mechanisms involved in the control of RNase E in other bacteria largely remain unknown. Cyanobacteria rely on solar light as an energy source for photosynthesis, despite the inherent ultraviolet (UV) irradiation. In this study, we first investigated globally the changes in gene expression in the cyanobacterium Synechocystis sp. PCC 6803 after a brief exposure to UV. Among the 407 responding genes 2 h after UV exposure was a prominent upregulation of rne mRNA level. Moreover, the enzymatic activity of RNase E rapidly increased as well, although the protein stability decreased. This unique response was underpinned by the increased accumulation of full-length rne mRNA caused by the stabilization of its 5' UTR and suppression of premature transcriptional termination, but not by an increased transcription rate. Mapping of RNA 3' ends and in vitro cleavage assays revealed that RNase E cleaves within a stretch of six consecutive uridine residues within the rne 5' UTR, indicating autoregulation. These observations suggest that RNase E in cyanobacteria contributes to reshaping the transcriptome during the UV stress response and that its required activity level is secured at the RNA level despite the enhanced turnover of the protein.
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Affiliation(s)
- Satoru Watanabe
- Faculty of Biology, Genetics and Experimental BioinformaticsUniversity of FreiburgFreiburgGermany
| | - Damir Stazic
- Department of BioscienceTokyo University of AgricultureSetagaya‐kuTokyoJapan
- Present address:
NexxiotPrime Tower (Hardstrasse 201)ZurichSwitzerland
| | - Jens Georg
- Department of BioscienceTokyo University of AgricultureSetagaya‐kuTokyoJapan
| | - Shota Ohtake
- Faculty of Biology, Genetics and Experimental BioinformaticsUniversity of FreiburgFreiburgGermany
| | - Yutaka Sakamaki
- Faculty of Biology, Genetics and Experimental BioinformaticsUniversity of FreiburgFreiburgGermany
| | - Megumi Numakura
- Faculty of Biology, Genetics and Experimental BioinformaticsUniversity of FreiburgFreiburgGermany
| | - Munehiko Asayama
- School of Agriculture, Molecular GeneticsIbaraki UniversityIbarakiJapan
| | - Taku Chibazakura
- Faculty of Biology, Genetics and Experimental BioinformaticsUniversity of FreiburgFreiburgGermany
| | - Annegret Wilde
- Faculty of Biology, Molecular GeneticsUniversity of FreiburgFreiburgGermany
| | - Claudia Steglich
- Department of BioscienceTokyo University of AgricultureSetagaya‐kuTokyoJapan
| | - Wolfgang R. Hess
- Department of BioscienceTokyo University of AgricultureSetagaya‐kuTokyoJapan
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11
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Kaltenbrunner A, Reimann V, Hoffmann UA, Aoyagi T, Sakata M, Nimura-Matsune K, Watanabe S, Steglich C, Wilde A, Hess WR. Regulation of pSYSA defense plasmid copy number in Synechocystis through RNase E and a highly transcribed asRNA. Front Microbiol 2023; 14:1112307. [PMID: 36876071 PMCID: PMC9978351 DOI: 10.3389/fmicb.2023.1112307] [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: 01/23/2023] [Indexed: 02/18/2023] Open
Abstract
Synthetic biology approaches toward the development of cyanobacterial producer strains require the availability of appropriate sets of plasmid vectors. A factor for the industrial usefulness of such strains is their robustness against pathogens, such as bacteriophages infecting cyanobacteria. Therefore, it is of great interest to understand the native plasmid replication systems and the CRISPR-Cas based defense mechanisms already present in cyanobacteria. In the model cyanobacterium Synechocystis sp. PCC 6803, four large and three smaller plasmids exist. The ~100 kb plasmid pSYSA is specialized in defense functions by encoding all three CRISPR-Cas systems and several toxin-antitoxin systems. The expression of genes located on pSYSA depends on the plasmid copy number in the cell. The pSYSA copy number is positively correlated with the expression level of the endoribonuclease E. As molecular basis for this correlation we identified the RNase E-mediated cleavage within the pSYSA-encoded ssr7036 transcript. Together with a cis-encoded abundant antisense RNA (asRNA1), this mechanism resembles the control of ColE1-type plasmid replication by two overlapping RNAs, RNA I and II. In the ColE1 mechanism, two non-coding RNAs interact, supported by the small protein Rop, which is encoded separately. In contrast, in pSYSA the similar-sized protein Ssr7036 is encoded within one of the interacting RNAs and it is this mRNA that likely primes pSYSA replication. Essential for plasmid replication is furthermore the downstream encoded protein Slr7037 featuring primase and helicase domains. Deletion of slr7037 led to the integration of pSYSA into the chromosome or the other large plasmid pSYSX. Moreover, the presence of slr7037 was required for successful replication of a pSYSA-derived vector in another model cyanobacterium, Synechococcus elongatus PCC 7942. Therefore, we annotated the protein encoded by slr7037 as Cyanobacterial Rep protein A1 (CyRepA1). Our findings open new perspectives on the development of shuttle vectors for genetic engineering of cyanobacteria and of modulating the activity of the entire CRISPR-Cas apparatus in Synechocystis sp. PCC 6803.
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Affiliation(s)
- Alena Kaltenbrunner
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Viktoria Reimann
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Ute A. Hoffmann
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Tomohiro Aoyagi
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Minori Sakata
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | | | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Tokyo, Japan
| | - Claudia Steglich
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Annegret Wilde
- Molecular Genetics of Prokaryotes, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Wolfgang R. Hess
- Genetics and Experimental Bioinformatics Group, Faculty of Biology, University of Freiburg, Freiburg, Germany
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12
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Tesson F, Bernheim A. Synergy and regulation of antiphage systems: toward the existence of a bacterial immune system? Curr Opin Microbiol 2023; 71:102238. [PMID: 36423502 DOI: 10.1016/j.mib.2022.102238] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 11/23/2022]
Abstract
Bacteria encode a vast repertoire of diverse antiphage defense systems. Recent studies revealed that different defense systems are often encoded within the same genome, raising the question of their possible interactions in a cell. Here, we review the known synergies and coregulations of antiphage systems. The emerging complexities suggest a potential existence of an additional level of organization of antiviral defense in prokaryotes. We argue that this organization could be compared with immune systems of animals and plants. We discuss this concept and explore what it could mean in bacteria.
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13
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Zhang H, Liu Q, Liang Q, Wang B, Chen Z, Wang J. Expression of tardigrade disordered proteins impacts the tolerance to biofuels in a model cyanobacterium Synechocystis sp. PCC 6803. Front Microbiol 2023; 13:1091502. [PMID: 36687595 PMCID: PMC9845703 DOI: 10.3389/fmicb.2022.1091502] [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: 11/07/2022] [Accepted: 12/12/2022] [Indexed: 01/05/2023] Open
Abstract
Tardigrades, known colloquially as water bears or moss piglets, are diminutive animals capable of surviving many extreme environments, even been exposed to space in low Earth orbit. Recently termed tardigrade disordered proteins (TDPs) include three families as cytoplasmic-(CAHS), secreted-(SAHS), and mitochondrial-abundant heat soluble (MAHS) proteins. How these tiny animals survive these stresses has remained relatively mysterious. Cyanobacteria cast attention as a "microbial factory" to produce biofuels and high-value-added chemicals due to their ability to photosynthesis and CO2 sequestration. We explored a lot about biofuel stress and related mechanisms in Synechocystis sp. PCC 6803. The previous studies show that CAHS protein heterogenous expression in bacteria, yeast, and human cells increases desiccation tolerance in these hosts. In this study, the expression of three CAHS proteins in cyanobacterium was found to affect the tolerance to biofuels, while the tolerance to Cd2+ and Zn2+ were slightly affected in several mutants. A quantitative transcriptomics approach was applied to decipher response mechanisms at the transcriptional level further.
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Affiliation(s)
- Heao Zhang
- Whittle School and Studios, Shenzhen, Guangdong, China
| | - Qingyang Liu
- Whittle School and Studios, Shenzhen, Guangdong, China
| | - Qing Liang
- Shenzhen Link Spider Technology Co., Ltd., Shenzhen, China
| | - Boxiang Wang
- Shenzhen Link Spider Technology Co., Ltd., Shenzhen, China,*Correspondence: Boxiang Wang, Zixi Chen
| | - Zixi Chen
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China,*Correspondence: Boxiang Wang, Zixi Chen
| | - Jiangxin Wang
- Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
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14
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Ding J, Schuergers N, Baehre H, Wilde A. Enzymatic properties of CARF-domain proteins in Synechocystis sp. PCC 6803. Front Microbiol 2022; 13:1046388. [DOI: 10.3389/fmicb.2022.1046388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022] Open
Abstract
Prokaryotic CRISPR-Cas (clustered regularly interspaced short palindromic repeats and CRISPR-associated genes) systems provide immunity against invading genetic elements such as bacteriophages and plasmids. In type III CRISPR systems, the recognition of target RNA leads to the synthesis of cyclic oligoadenylate (cOA) second messengers that activate ancillary effector proteins via their CRISPR-associated Rossmann fold (CARF) domains. Commonly, these are ribonucleases (RNases) that unspecifically degrade both invader and host RNA. To mitigate adverse effects on cell growth, ring nucleases can degrade extant cOAs to switch off ancillary nucleases. Here we show that the model organism Synechocystis sp. PCC 6803 harbors functional CARF-domain effector and ring nuclease proteins. We purified and characterized the two ancillary CARF-domain proteins from the III-D type CRISPR system of this cyanobacterium. The Csx1 homolog, SyCsx1, is a cyclic tetraadenylate(cA4)-dependent RNase with a strict specificity for cytosine nucleotides. The second CARF-domain protein with similarity to Csm6 effectors, SyCsm6, did not show RNase activity in vitro but was able to break down cOAs and attenuate SyCsx1 RNase activity. Our data suggest that the CRISPR systems in Synechocystis confer a multilayered cA4-mediated defense mechanism.
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15
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Bolay P, Schlüter S, Grimm S, Riediger M, Hess WR, Klähn S. The transcriptional regulator RbcR controls ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) genes in the cyanobacterium Synechocystis sp. PCC 6803. THE NEW PHYTOLOGIST 2022; 235:432-445. [PMID: 35377491 DOI: 10.1111/nph.18139] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/19/2022] [Indexed: 06/14/2023]
Abstract
Oxygenic photosynthesis evolved in cyanobacteria, primary producers of striking ecological importance. Like plants, cyanobacteria use the Calvin-Benson-Bassham cycle for CO2 fixation, fuelled by ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO). In a competitive reaction this enzyme also fixes O2 which makes it rather ineffective. To mitigate this problem, cyanobacteria evolved a CO2 concentrating mechanism (CCM) to pool CO2 in the vicinity of RuBisCO. However, the regulation of these carbon (C) assimilatory systems is understood only partially. Using the model Synechocystis sp. PCC 6803 we characterized an essential LysR-type transcriptional regulator encoded by gene sll0998. Transcript profiling of a knockdown mutant revealed diminished expression of several genes involved in C acquisition, including rbcLXS, sbtA and ccmKL encoding RuBisCO and parts of the CCM, respectively. We demonstrate that the Sll0998 protein binds the rbcL promoter and acts as a RuBisCO regulator (RbcR). We propose ATTA(G/A)-N5 -(C/T)TAAT as the binding motif consensus. Our data validate RbcR as a regulator of inorganic C assimilation and define the regulon controlled by it. Biological CO2 fixation can sustain efforts to reduce its atmospheric concentrations and is fundamental for the light-driven production of chemicals directly from CO2 . Information about the involved regulatory and physiological processes is crucial to engineer cyanobacterial cell factories.
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Affiliation(s)
- Paul Bolay
- Department of Solar Materials, Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Susan Schlüter
- Department of Solar Materials, Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Samuel Grimm
- Department of Solar Materials, Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Matthias Riediger
- Genetics & Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
| | - Wolfgang R Hess
- Genetics & Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
| | - Stephan Klähn
- Department of Solar Materials, Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318, Leipzig, Germany
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16
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Mantovani O, Reimann V, Haffner M, Herrmann FP, Selim KA, Forchhammer K, Hess WR, Hagemann M. The impact of the cyanobacterial carbon-regulator protein SbtB and of the second messengers cAMP and c-di-AMP on CO 2 -dependent gene expression. THE NEW PHYTOLOGIST 2022; 234:1801-1816. [PMID: 35285042 DOI: 10.1111/nph.18094] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
The amount of inorganic carbon (Ci ) fluctuates in aquatic environments. Cyanobacteria evolved a Ci -concentrating mechanism (CCM) that is regulated at different levels. The regulator SbtB binds to the second messengers cAMP or c-di-AMP and is involved in acclimation to low Ci (LC) in Synechocystis sp. PCC 6803. Here, we investigated the role of SbtB and of associated second messengers at different Ci conditions. The transcriptome of wild-type (WT) Synechocystis and the ΔsbtB mutant were compared with Δcya1, a mutant defective in cAMP production, and ΔdacA, a mutant defective in generating c-di-AMP. A defined subset of LC-regulated genes in the WT was already changed in ΔsbtB under high Ci (HC) conditions. This response of ΔsbtB correlated with a diminished induction of many CCM-associated genes after LC shift in this mutant. The Δcya1 mutant showed less deviation from WT, whereas ΔdacA induced CCM-associated genes under HC. Metabolome analysis also revealed differences between the strains, whereby ΔsbtB showed slower accumulation of 2-phosphoglycolate and ΔdacA differences among amino acids compared to WT. Collectively, these results indicate that SbtB regulates a subset of LC acclimation genes while c-di-AMP and especially cAMP appear to have a lesser impact on gene expression under different Ci availabilities.
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Affiliation(s)
- Oliver Mantovani
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, D-18059, Germany
| | - Viktoria Reimann
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, D-79104, Germany
| | - Michael Haffner
- Department of Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, D-72076, Germany
| | - Felix Philipp Herrmann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, D-18059, Germany
| | - Khaled A Selim
- Department of Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, D-72076, Germany
| | - Karl Forchhammer
- Department of Organismic Interactions, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, D-72076, Germany
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Freiburg, D-79104, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, Rostock, D-18059, Germany
- Department Life, Light and Matter, Interdisciplinary Faculty, University of Rostock, Rostock, D-18059, Germany
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17
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Luyten Y, Hausman DE, Young JC, Doyle L, Higashi K, Ubilla-Rodriguez N, Lambert AR, Arroyo CS, Forsberg K, Morgan R, Stoddard B, Kaiser B. Identification and characterization of the WYL BrxR protein and its gene as separable regulatory elements of a BREX phage restriction system. Nucleic Acids Res 2022; 50:5171-5190. [PMID: 35511079 PMCID: PMC9122589 DOI: 10.1093/nar/gkac311] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 11/16/2022] Open
Abstract
Bacteriophage exclusion ('BREX') phage restriction systems are found in a wide range of bacteria. Various BREX systems encode unique combinations of proteins that usually include a site-specific methyltransferase; none appear to contain a nuclease. Here we describe the identification and characterization of a Type I BREX system from Acinetobacter and the effect of deleting each BREX ORF on growth, methylation, and restriction. We identified a previously uncharacterized gene in the BREX operon that is dispensable for methylation but involved in restriction. Biochemical and crystallographic analyses of this factor, which we term BrxR ('BREX Regulator'), demonstrate that it forms a homodimer and specifically binds a DNA target site upstream of its transcription start site. Deletion of the BrxR gene causes cell toxicity, reduces restriction, and significantly increases the expression of BrxC. In contrast, the introduction of a premature stop codon into the BrxR gene, or a point mutation blocking its DNA binding ability, has little effect on restriction, implying that the BrxR coding sequence and BrxR protein play independent functional roles. We speculate that elements within the BrxR coding sequence are involved in cis regulation of anti-phage activity, while the BrxR protein itself plays an additional regulatory role, perhaps during horizontal transfer.
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Affiliation(s)
- Yvette A Luyten
- New England Biolabs, 240 County Road, Ipswich, MA 01938, USA
| | - Deanna E Hausman
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Juliana C Young
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Lindsey A Doyle
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Kerilyn M Higashi
- Department of Biology, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA
| | - Natalia C Ubilla-Rodriguez
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Abigail R Lambert
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Corina S Arroyo
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Kevin J Forsberg
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | | | - Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. North, Seattle, WA 98109, USA
| | - Brett K Kaiser
- Department of Biology, Seattle University, 901 12th Avenue, Seattle, WA 98122, USA
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18
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Picton DM, Harling-Lee JD, Duffner SJ, Went SC, Morgan RD, Hinton JCD, Blower TR. A widespread family of WYL-domain transcriptional regulators co-localizes with diverse phage defence systems and islands. Nucleic Acids Res 2022; 50:5191-5207. [PMID: 35544231 PMCID: PMC9122601 DOI: 10.1093/nar/gkac334] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/28/2022] [Accepted: 04/21/2022] [Indexed: 01/21/2023] Open
Abstract
Bacteria are under constant assault by bacteriophages and other mobile genetic elements. As a result, bacteria have evolved a multitude of systems that protect from attack. Genes encoding bacterial defence mechanisms can be clustered into 'defence islands', providing a potentially synergistic level of protection against a wider range of assailants. However, there is a comparative paucity of information on how expression of these defence systems is controlled. Here, we functionally characterize a transcriptional regulator, BrxR, encoded within a recently described phage defence island from a multidrug resistant plasmid of the emerging pathogen Escherichia fergusonii. Using a combination of reporters and electrophoretic mobility shift assays, we discovered that BrxR acts as a repressor. We present the structure of BrxR to 2.15 Å, the first structure of this family of transcription factors, and pinpoint a likely binding site for ligands within the WYL-domain. Bioinformatic analyses demonstrated that BrxR-family homologues are widespread amongst bacteria. About half (48%) of identified BrxR homologues were co-localized with a diverse array of known phage defence systems, either alone or clustered into defence islands. BrxR is a novel regulator that reveals a common mechanism for controlling the expression of the bacterial phage defence arsenal.
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Affiliation(s)
- David M Picton
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Joshua D Harling-Lee
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK.,The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Edinburgh EH25 9RG, UK
| | - Samuel J Duffner
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | - Sam C Went
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
| | | | - Jay C D Hinton
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - Tim R Blower
- Department of Biosciences, Durham University, Stockton Road, Durham DH1 3LE, UK
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19
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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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20
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Klähn S, Mikkat S, Riediger M, Georg J, Hess WR, Hagemann M. Integrative analysis of the salt stress response in cyanobacteria. Biol Direct 2021; 16:26. [PMID: 34906211 PMCID: PMC8670252 DOI: 10.1186/s13062-021-00316-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 11/29/2021] [Indexed: 12/24/2022] Open
Abstract
Microorganisms evolved specific acclimation strategies to thrive in environments of high or fluctuating salinities. Here, salt acclimation in the model cyanobacterium Synechocystis sp. PCC 6803 was analyzed by integrating transcriptomic, proteomic and metabolomic data. A dynamic reorganization of the transcriptome occurred during the first hours after salt shock, e.g. involving the upregulation of genes to activate compatible solute biochemistry balancing osmotic pressure. The massive accumulation of glucosylglycerol then had a measurable impact on the overall carbon and nitrogen metabolism. In addition, we observed the coordinated induction of putative regulatory RNAs and of several proteins known for their involvement in other stress responses. Overall, salt-induced changes in the proteome and transcriptome showed good correlations, especially among the stably up-regulated proteins and their transcripts. We define an extended salt stimulon comprising proteins directly or indirectly related to compatible solute metabolism, ion and water movements, and a distinct set of regulatory RNAs involved in post-transcriptional regulation. Our comprehensive data set provides the basis for engineering cyanobacterial salt tolerance and to further understand its regulation.
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Affiliation(s)
- Stephan Klähn
- Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Leipzig, Germany
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Stefan Mikkat
- Core Facility Proteome Analysis, Rostock University Medical Center, Rostock, Germany
| | - Matthias Riediger
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Jens Georg
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Wolfgang R. Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Martin Hagemann
- Department of Plant Physiology, Institute of Biosciences, University of Rostock, A.-Einstein-Str. 3, 18059 Rostock, Germany
- Department Life, Light and Matter, University of Rostock, Rostock, Germany
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21
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Lupacchini S, Appel J, Stauder R, Bolay P, Klähn S, Lettau E, Adrian L, Lauterbach L, Bühler B, Schmid A, Toepel J. Rewiring cyanobacterial photosynthesis by the implementation of an oxygen-tolerant hydrogenase. Metab Eng 2021; 68:199-209. [PMID: 34673236 DOI: 10.1016/j.ymben.2021.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/11/2021] [Accepted: 10/16/2021] [Indexed: 10/20/2022]
Abstract
Molecular hydrogen (H2) is considered as an ideal energy carrier to replace fossil fuels in future. Biotechnological H2 production driven by oxygenic photosynthesis appears highly promising, as biocatalyst and H2 syntheses rely mainly on light, water, and CO2 and not on rare metals. This biological process requires coupling of the photosynthetic water oxidizing apparatus to a H2-producing hydrogenase. However, this strategy is impeded by the simultaneous release of oxygen (O2) which is a strong inhibitor of most hydrogenases. Here, we addressed this challenge, by the introduction of an O2-tolerant hydrogenase into phototrophic bacteria, namely the cyanobacterial model strain Synechocystis sp. PCC 6803. To this end, the gene cluster encoding the soluble, O2-tolerant, and NAD(H)-dependent hydrogenase from Ralstonia eutropha (ReSH) was functionally transferred to a Synechocystis strain featuring a knockout of the native O2 sensitive hydrogenase. Intriguingly, photosynthetically active cells produced the O2 tolerant ReSH, and activity was confirmed in vitro and in vivo. Further, ReSH enabled the constructed strain Syn_ReSH+ to utilize H2 as sole electron source to fix CO2. Syn_ReSH+ also was able to produce H2 under dark fermentative conditions as well as in presence of light, under conditions fostering intracellular NADH excess. These findings highlight a high level of interconnection between ReSH and cyanobacterial redox metabolism. This study lays a foundation for further engineering, e.g., of electron transfer to ReSH via NADPH or ferredoxin, to finally enable photosynthesis-driven H2 production.
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Affiliation(s)
- Sara Lupacchini
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Jens Appel
- Department of Biology, Botanical Institute, University Kiel, 24118, Kiel, Germany
| | - Ron Stauder
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Paul Bolay
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Stephan Klähn
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Elisabeth Lettau
- Institute for Chemistry, Technische Universität Berlin, 10623, Berlin, Germany
| | - Lorenz Adrian
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany; Chair of Geobiotechnology, Technische Universität Berlin, 10923, Berlin, Germany
| | - Lars Lauterbach
- Institute for Chemistry, Technische Universität Berlin, 10623, Berlin, Germany; Institute of Applied Microbiology, Rheinisch-Westfälische Technische Hochschule Aachen, 52074, Aachen, Germany
| | - Bruno Bühler
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Andreas Schmid
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Jörg Toepel
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany.
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22
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Baliga P, Shekar M, Tg P, Sk G. Investigation into the prevalent CRISPR-Cas systems among the Aeromonas genus. J Basic Microbiol 2021; 61:874-882. [PMID: 34486151 DOI: 10.1002/jobm.202100234] [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] [Received: 05/11/2021] [Revised: 08/12/2021] [Accepted: 08/21/2021] [Indexed: 01/15/2023]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) is a prokaryotic adaptive immune system that checks invasion by mobile genetic elements through nuclease targeting. In this study, we investigated the occurrence, diversity, and features of the CRISPR system in the genus Aeromonas using bioinformatics tools. Only 13 out of 122 complete genomes (10.66%) of the genus Aeromonas from the NCBI GenBank database harbored the CRISPR system. The Type I-F system was the most prevalent CRISPR system among the Aeromonads, followed by the Type I-E system. Only one strain harbored a Type I-C CRISPR system. Among the Aeromonads, Aeromonas caviae (22.7%) and Aeromonas veronii (20%) had a higher prevalence rate of the complete CRISPR system. The analysis of direct repeat (DR) sequences showed that all could form stable RNA secondary structures. A phylogenetic tree generated for the Cas1 protein classified CRISPR subtypes into three distinct clusters. Among the 748 spacers investigated, 41.98% and 17.25% showed perfect homology to phage and plasmid sequences, respectively. Some arrays had duplicated spacers. The CRISPR loci are closely linked to antibiotic resistance genes in most strains. Collectively, our results would contribute to research on antibiotic resistance in the Aeromonas group, and provide new insights into the diversity and evolution of the CRISPR-Cas system.
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Affiliation(s)
- Pallavi Baliga
- Department of Aquatic Animal Health Management, College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Mangalore, Karnataka, India
| | - Malathi Shekar
- Department of Aquatic Animal Health Management, College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Mangalore, Karnataka, India
| | - Puneeth Tg
- Department of Aquatic Animal Health Management, College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Mangalore, Karnataka, India
| | - Girisha Sk
- Department of Aquatic Animal Health Management, College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Mangalore, Karnataka, India
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23
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Zhan J, Steglich C, Scholz I, Hess WR, Kirilovsky D. Inverse regulation of light harvesting and photoprotection is mediated by a 3'-end-derived sRNA in cyanobacteria. THE PLANT CELL 2021; 33:358-380. [PMID: 33793852 PMCID: PMC8136909 DOI: 10.1093/plcell/koaa030] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 12/01/2020] [Indexed: 06/12/2023]
Abstract
Phycobilisomes (PBSs), the principal cyanobacterial antenna, are among the most efficient macromolecular structures in nature, and are used for both light harvesting and directed energy transfer to the photosynthetic reaction center. However, under unfavorable conditions, excess excitation energy needs to be rapidly dissipated to avoid photodamage. The orange carotenoid protein (OCP) senses light intensity and induces thermal energy dissipation under stress conditions. Hence, its expression must be tightly controlled; however, the molecular mechanism of this regulation remains to be elucidated. Here, we describe the discovery of a posttranscriptional regulatory mechanism in Synechocystis sp. PCC 6803 in which the expression of the operon encoding the allophycocyanin subunits of the PBS is directly and in an inverse fashion linked to the expression of OCP. This regulation is mediated by ApcZ, a small regulatory RNA that is derived from the 3'-end of the tetracistronic apcABC-apcZ operon. ApcZ inhibits ocp translation under stress-free conditions. Under most stress conditions, apc operon transcription decreases and ocp translation increases. Thus, a key operon involved in the collection of light energy is functionally connected to the expression of a protein involved in energy dissipation. Our findings support the view that regulatory RNA networks in bacteria evolve through the functionalization of mRNA 3'-UTRs.
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Affiliation(s)
- Jiao Zhan
- Université Paris-Saclay, Commissariat à l’Énergie Atomiques et aux Énergies Alternatives, Centre National de la Recherche Scientifique (CEA, CNRS), Institute for Integrative Biology of the Cell (I2BC), 91198 Gif sur Yvette, France
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Claudia Steglich
- Faculty of Biology, Institute of Biology III, University of Freiburg, D-79104 Freiburg im Breisgau, Germany
| | - Ingeborg Scholz
- Faculty of Biology, Institute of Biology III, University of Freiburg, D-79104 Freiburg im Breisgau, Germany
| | - Wolfgang R Hess
- Faculty of Biology, Institute of Biology III, University of Freiburg, D-79104 Freiburg im Breisgau, Germany
| | - Diana Kirilovsky
- Université Paris-Saclay, Commissariat à l’Énergie Atomiques et aux Énergies Alternatives, Centre National de la Recherche Scientifique (CEA, CNRS), Institute for Integrative Biology of the Cell (I2BC), 91198 Gif sur Yvette, France
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Bolay P, Rozbeh R, Muro-Pastor MI, Timm S, Hagemann M, Florencio FJ, Forchhammer K, Klähn S. The Novel P II-Interacting Protein PirA Controls Flux into the Cyanobacterial Ornithine-Ammonia Cycle. mBio 2021; 12:e00229-21. [PMID: 33758091 PMCID: PMC8092223 DOI: 10.1128/mbio.00229-21] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 02/16/2021] [Indexed: 12/11/2022] Open
Abstract
Among prokaryotes, cyanobacteria have an exclusive position as they perform oxygenic photosynthesis. Cyanobacteria substantially differ from other bacteria in further aspects, e.g., they evolved a plethora of unique regulatory mechanisms to control primary metabolism. This is exemplified by the regulation of glutamine synthetase (GS) via small proteins termed inactivating factors (IFs). Here, we reveal another small protein, encoded by the ssr0692 gene in the model strain Synechocystis sp. PCC 6803, that regulates flux into the ornithine-ammonia cycle (OAC), the key hub of cyanobacterial nitrogen stockpiling and remobilization. This regulation is achieved by the interaction with the central carbon/nitrogen control protein PII, which commonly controls entry into the OAC by activating the key enzyme of arginine synthesis, N-acetyl-l-glutamate kinase (NAGK). In particular, the Ssr0692 protein competes with NAGK for PII binding and thereby prevents NAGK activation, which in turn lowers arginine synthesis. Accordingly, we termed it PII-interacting regulator of arginine synthesis (PirA). Similar to the GS IFs, PirA accumulates in response to ammonium upshift due to relief from repression by the global nitrogen control transcription factor NtcA. Consistent with this, the deletion of pirA affects the balance of metabolite pools of the OAC in response to ammonium shocks. Moreover, the PirA-PII interaction requires ADP and is prevented by PII mutations affecting the T-loop conformation, the major protein interaction surface of this signal processing protein. Thus, we propose that PirA is an integrator determining flux into N storage compounds not only depending on the N availability but also the energy state of the cell.IMPORTANCE Cyanobacteria contribute a significant portion to the annual oxygen yield and play important roles in biogeochemical cycles, e.g., as major primary producers. Due to their photosynthetic lifestyle, cyanobacteria also arouse interest as hosts for the sustainable production of fuel components and high-value chemicals. However, their broad application as microbial cell factories is hampered by limited knowledge about the regulation of metabolic fluxes in these organisms. Our research identified a novel regulatory protein that controls nitrogen flux, in particular arginine synthesis. Besides its role as a proteinogenic amino acid, arginine is a precursor for the cyanobacterial storage compound cyanophycin, which is of potential interest to biotechnology. Therefore, the obtained results will not only enhance our understanding of flux control in these organisms but also help to provide a scientific basis for targeted metabolic engineering and, hence, the design of photosynthesis-driven biotechnological applications.
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Affiliation(s)
- Paul Bolay
- Helmholtz Centre for Environmental Research, Department of Solar Materials, Leipzig, Germany
| | - Rokhsareh Rozbeh
- Interfaculty Institute for Microbiology and Infection Medicine, Organismic Interactions Department, Tübingen University, Tübingen, Germany
| | - M Isabel Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, Spain
| | - Stefan Timm
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Martin Hagemann
- Department of Plant Physiology, University of Rostock, Rostock, Germany
| | - Francisco J Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, Spain
| | - Karl Forchhammer
- Interfaculty Institute for Microbiology and Infection Medicine, Organismic Interactions Department, Tübingen University, Tübingen, Germany
| | - Stephan Klähn
- Helmholtz Centre for Environmental Research, Department of Solar Materials, Leipzig, Germany
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McBride TM, Schwartz EA, Kumar A, Taylor DW, Fineran PC, Fagerlund RD. Diverse CRISPR-Cas Complexes Require Independent Translation of Small and Large Subunits from a Single Gene. Mol Cell 2020; 80:971-979.e7. [PMID: 33248026 DOI: 10.1016/j.molcel.2020.11.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/22/2020] [Accepted: 10/29/2020] [Indexed: 12/26/2022]
Abstract
CRISPR-Cas adaptive immune systems provide prokaryotes with defense against viruses by degradation of specific invading nucleic acids. Despite advances in the biotechnological exploitation of select systems, multiple CRISPR-Cas types remain uncharacterized. Here, we investigated the previously uncharacterized type I-D interference complex and revealed that it is a genetic and structural hybrid with similarity to both type I and type III systems. Surprisingly, formation of the functional complex required internal in-frame translation of small subunits from within the large subunit gene. We further show that internal translation to generate small subunits is widespread across diverse type I-D, I-B, and I-C systems, which account for roughly one quarter of CRISPR-Cas systems. Our work reveals the unexpected expansion of protein coding potential from within single cas genes, which has important implications for understanding CRISPR-Cas function and evolution.
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Affiliation(s)
- Tess M McBride
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - Evan A Schwartz
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712-1597, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712-1597, USA
| | - Abhishek Kumar
- Centre for Protein Research, University of Otago, PO Box 56, Dunedin 9054, New Zealand
| | - David W Taylor
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712-1597, USA; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712-1597, USA; Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX 78712-1597, USA; LIVESTRONG Cancer Institutes, Dell Medical School, Austin, TX 78712-1597, USA
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand; Bio-Protection Research Centre, University of Otago, PO Box 56, Dunedin 9054, New Zealand; Genetics Otago, University of Otago, Dunedin, New Zealand
| | - Robert D Fagerlund
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9054, New Zealand; Genetics Otago, University of Otago, Dunedin, New Zealand.
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Pattharaprachayakul N, Lee M, Incharoensakdi A, Woo HM. Current understanding of the cyanobacterial CRISPR-Cas systems and development of the synthetic CRISPR-Cas systems for cyanobacteria. Enzyme Microb Technol 2020; 140:109619. [PMID: 32912679 DOI: 10.1016/j.enzmictec.2020.109619] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 05/14/2020] [Accepted: 06/05/2020] [Indexed: 11/20/2022]
Abstract
Cyanobacteria are photosynthetic microorganisms that are capable of converting CO2 to value-added chemicals. Engineering of cyanobacteria with synthetic biology tools, including the CRISPR-Cas system, has allowed an opportunity for biological CO2 utilization. Here, we described natural CRISPR-Cas systems for understanding cyanobacterial genomics and synthetic CRISPR-Cas systems for metabolic engineering applications. The natural CRISPR-Cas systems in cyanobacteria have been identified as Class 1, with type I and III, and some Class 2, with type V, as an adaptive immune system against viral invasion. As synthetic tools, CRISPR-Cas9 and -Cas12a have been successfully established in cyanobacteria to delete a target gene without a selection marker. Deactivated Cas9 and Cas12a have also been used to repress genes for metabolic engineering. In addition, a perspective on how advanced CRISPR-Cas systems and a pool of the guide RNAs can be advantageous for precise genome engineering and understanding of unknown functions was discussed for advanced engineering of cyanobacteria.
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Affiliation(s)
- Napisa Pattharaprachayakul
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, 16419, Republic of Korea; Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok, 10330 Thailand; Program in Biotechnology, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok, 10330, Thailand
| | - Mieun Lee
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, 16419, Republic of Korea
| | - Aran Incharoensakdi
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road, Pathumwan, Bangkok, 10330 Thailand
| | - Han Min Woo
- Department of Food Science and Biotechnology, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, 16419, Republic of Korea; BioFoundry Research Center, Institute of Biotechnology and Bioengineering, Sungkyunkwan University (SKKU), 2066 Seobu-ro, Jangan-gu, Suwon, 16419, Republic of Korea.
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Solovchenko A, Gorelova O, Karpova O, Selyakh I, Semenova L, Chivkunova O, Baulina O, Vinogradova E, Pugacheva T, Scherbakov P, Vasilieva S, Lukyanov A, Lobakova E. Phosphorus Feast and Famine in Cyanobacteria: Is Luxury Uptake of the Nutrient Just a Consequence of Acclimation to Its Shortage? Cells 2020; 9:E1933. [PMID: 32825634 PMCID: PMC7564538 DOI: 10.3390/cells9091933] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/12/2020] [Accepted: 08/20/2020] [Indexed: 01/02/2023] Open
Abstract
To cope with fluctuating phosphorus (P) availability, cyanobacteria developed diverse acclimations, including luxury P uptake (LPU)-taking up P in excess of the current metabolic demand. LPU is underexplored, despite its importance for nutrient-driven rearrangements in aquatic ecosystems. We studied the LPU after the refeeding of P-deprived cyanobacterium Nostoc sp. PCC 7118 with inorganic phosphate (Pi), including the kinetics of Pi uptake, turnover of polyphosphate, cell ultrastructure, and gene expression. The P-deprived cells deployed acclimations to P shortage (reduction of photosynthetic apparatus and mobilization of cell P reserves). The P-starved cells capable of LPU exhibited a biphasic kinetic of the Pi uptake and polyphosphate formation. The first (fast) phase (1-2 h after Pi refeeding) occurred independently of light and temperature. It was accompanied by a transient accumulation of polyphosphate, still upregulated genes encoding high-affinity Pi transporters, and an ATP-dependent polyphosphate kinase. During the second (slow) phase, recovery from P starvation was accompanied by the downregulation of these genes. Our study revealed no specific acclimation to ample P conditions in Nostoc sp. PCC 7118. We conclude that the observed LPU phenomenon does not likely result from the activation of a mechanism specific for ample P conditions. On the contrary, it stems from slow disengagement of the low-P responses after the abrupt transition from low-P to ample P conditions.
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Affiliation(s)
- Alexei Solovchenko
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
- Ecology Research Laboratory, Pskov State University, 180000 Pskov, Russia
- Institute of Natural Sciences, Derzhavin Tambov State University, 392000 Tambov, Russia
| | - Olga Gorelova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Olga Karpova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Irina Selyakh
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Larisa Semenova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Olga Chivkunova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Olga Baulina
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Elizaveta Vinogradova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Tatiana Pugacheva
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Pavel Scherbakov
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Svetlana Vasilieva
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Alexandr Lukyanov
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
| | - Elena Lobakova
- Faculty of Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; (O.G.); (O.K.); (I.S.); (L.S.); (O.C.); (O.B.); (E.V.); (T.P.); (P.S.); (S.V.); (A.L.)
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28
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Behler J, Hess WR. Approaches to study CRISPR RNA biogenesis and the key players involved. Methods 2020; 172:12-26. [PMID: 31325492 DOI: 10.1016/j.ymeth.2019.07.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/29/2019] [Accepted: 07/15/2019] [Indexed: 12/26/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins provide an inheritable and adaptive immune system against phages and foreign genetic elements in many bacteria and archaea. The three stages of CRISPR-Cas immunity comprise adaptation, CRISPR RNA (crRNA) biogenesis and interference. The maturation of the pre-crRNA into mature crRNAs, short guide RNAs that target invading nucleic acids, is crucial for the functionality of CRISPR-Cas defense systems. Mature crRNAs assemble with Cas proteins into the ribonucleoprotein (RNP) effector complex and guide the Cas nucleases to the cognate foreign DNA or RNA target. Experimental approaches to characterize these crRNAs, the specific steps toward their maturation and the involved factors, include RNA-seq analyses, enzyme assays, methods such as cryo-electron microscopy, the crystallization of proteins, or UV-induced protein-RNA crosslinking coupled to mass spectrometry analysis. Complex and multiple interactions exist between CRISPR-cas-encoded specific riboendonucleases such as Cas6, Cas5d and Csf5, endonucleases with dual functions in maturation and interference such as the enzymes of the Cas12 and Cas13 families, and nucleases belonging to the cell's degradosome such as RNase E, PNPase and RNase J, both in the maturation as well as in interference. The results of these studies have yielded a picture of unprecedented diversity of sequences, enzymes and biochemical mechanisms.
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Affiliation(s)
- Juliane Behler
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104 Freiburg, Germany
| | - Wolfgang R Hess
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104 Freiburg, Germany; University of Freiburg, Freiburg Institute for Advanced Studies, Albertstr. 19, D-79104 Freiburg, Germany.
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29
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Almendros C, Nobrega FL, McKenzie RE, Brouns SJJ. Cas4-Cas1 fusions drive efficient PAM selection and control CRISPR adaptation. Nucleic Acids Res 2019; 47:5223-5230. [PMID: 30937444 PMCID: PMC6547450 DOI: 10.1093/nar/gkz217] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/15/2019] [Accepted: 03/28/2019] [Indexed: 12/24/2022] Open
Abstract
Microbes have the unique ability to acquire immunological memories from mobile genetic invaders to protect themselves from predation. To confer CRISPR resistance, new spacers need to be compatible with a targeting requirement in the invader's DNA called the protospacer adjacent motif (PAM). Many CRISPR systems encode Cas4 proteins to ensure new spacers are integrated that meet this targeting prerequisite. Here we report that a gene fusion between cas4 and cas1 from the Geobacter sulfurreducens I-U CRISPR-Cas system is capable of introducing functional spacers carrying interference proficient TTN PAM sequences at much higher frequencies than unfused Cas4 adaptation modules. Mutations of Cas4-domain catalytic residues resulted in dramatically decreased naïve and primed spacer acquisition, and a loss of PAM selectivity showing that the Cas4 domain controls Cas1 activity. We propose the fusion gene evolved to drive the acquisition of only PAM-compatible spacers to optimize CRISPR interference.
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Affiliation(s)
- Cristóbal Almendros
- Kavli Institute of Nanoscience, Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
| | - Franklin L Nobrega
- Kavli Institute of Nanoscience, Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
| | - Rebecca E McKenzie
- Kavli Institute of Nanoscience, Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands
| | - Stan J J Brouns
- Kavli Institute of Nanoscience, Department of Bionanoscience, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, Netherlands.,Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, Netherlands
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30
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Müller AU, Leibundgut M, Ban N, Weber-Ban E. Structure and functional implications of WYL domain-containing bacterial DNA damage response regulator PafBC. Nat Commun 2019; 10:4653. [PMID: 31604936 PMCID: PMC6789036 DOI: 10.1038/s41467-019-12567-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 09/16/2019] [Indexed: 01/15/2023] Open
Abstract
In mycobacteria, transcriptional activator PafBC is responsible for upregulating the majority of genes induced by DNA damage. Understanding the mechanism of PafBC activation is impeded by a lack of structural information on this transcription factor that contains a widespread, but poorly understood WYL domain frequently encountered in bacterial transcription factors. Here, we determine the crystal structure of Arthrobacter aurescens PafBC. The protein consists of two modules, each harboring an N-terminal helix-turn-helix DNA-binding domain followed by a central WYL and a C-terminal extension (WCX) domain. The WYL domains exhibit Sm-folds, while the WCX domains adopt ferredoxin-like folds, both characteristic for RNA-binding proteins. Our results suggest a mechanism of regulation in which WYL domain-containing transcription factors may be activated by binding RNA or other nucleic acid molecules. Using an in vivo mutational screen in Mycobacterium smegmatis, we identify potential co-activator binding sites on PafBC.
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Affiliation(s)
- Andreas U Müller
- ETH Zurich, Institute of Molecular Biology and Biophysics, CH-8093, Zurich, Switzerland
| | - Marc Leibundgut
- ETH Zurich, Institute of Molecular Biology and Biophysics, CH-8093, Zurich, Switzerland
| | - Nenad Ban
- ETH Zurich, Institute of Molecular Biology and Biophysics, CH-8093, Zurich, Switzerland
| | - Eilika Weber-Ban
- ETH Zurich, Institute of Molecular Biology and Biophysics, CH-8093, Zurich, Switzerland.
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Scholz I, Lott SC, Behler J, Gärtner K, Hagemann M, Hess WR. Divergent methylation of CRISPR repeats and cas genes in a subtype I-D CRISPR-Cas-system. BMC Microbiol 2019; 19:147. [PMID: 31262257 PMCID: PMC6604393 DOI: 10.1186/s12866-019-1526-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 06/20/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The presence and activity of CRISPR-Cas defense systems is a hallmark of many prokaryotic microorganisms. Here, the distribution of sequences related to the highly iterated palindrome 1 (HIP1) element and the DNA methylation of CGATCG motifs embedded within HIP1 as a vital part of the CRISPR1 repeat sequence was analyzed in the cyanobacterium Synechocystis sp. PCC 6803. Previously suggested functions of HIP1 include organization of chromosomal structure, DNA recombination or gene regulation, all of which could be relevant in CRISPR-Cas functionality. RESULTS The CRISPR1 repeat-spacer array contains more than 50 CGATCG elements that are double-methylated (5mCG6mATCG) by the enzymes M.Ssp6803I and M.Ssp6803III. Hence, more than 200 possible methylation events cluster over a stretch of 3600 bp of double-stranded DNA. Bisulfite sequencing showed that these motifs were highly methylated at the m5CGATCG positions whereas specific motifs within the CRISPR1 cas genes were hypomethylated suggesting a lowered accessibility for the DNA methylase to these regions. Assays for conjugation and CRISPR1-mediated DNA interference revealed a 50% drop in conjugation efficiency in the mutant lacking the 5mC methylation of CGATCG motifs, while the highly efficient DNA interference activity was not affected by the lack of m5CGATCG DNA-methylation, nor was the capability to differentiate between self and non-self targets based on the protospacer adjacent motifs (PAMs) GTA and GTC versus the non-PAM AGC. A third DNA methylation mediated by M.Ssp6803II modifies the first cytosine in the motif GGCC yielding GGm4CC. We found a remarkable absence of GGCC motifs and hence the corresponding methylation over an 11 kb stretch encompassing all the cas genes involved in interference and crRNA maturation but not adaptation of the CRISPR1 system. CONCLUSIONS The lack of GGCC tetranucleotides along the CRISPR1 interference and maturation genes supports the reported hybrid character of subtype I-D CRISPR-Cas systems. We report tight and very high 5mC methylation of the CRISPR1 repeat sequences. Nevertheless, cells lacking the 5mC methylation activity were unaffected in their CRISPR1-mediated interference response but the efficiency of conjugation was reduced by 50%. These results point to an unknown role of m5CGATCG DNA-methylation marks in conjugation and DNA transformation.
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Affiliation(s)
- Ingeborg Scholz
- Faculty of Biology, Genetics an Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany
| | - Steffen C. Lott
- Faculty of Biology, Genetics an Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany
| | - Juliane Behler
- Faculty of Biology, Genetics an Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany
| | - Katrin Gärtner
- University of Rostock, Institute of Biosciences, Plant Physiology, A.-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Martin Hagemann
- University of Rostock, Institute of Biosciences, Plant Physiology, A.-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Wolfgang R. Hess
- Faculty of Biology, Genetics an Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany
- University of Freiburg, Freiburg Institute for Advanced Studies, Albertstr. 19, D-79104 Freiburg, Germany
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32
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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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Zhang H, Dong C, Li L, Wasney GA, Min J. Structural insights into the modulatory role of the accessory protein WYL1 in the Type VI-D CRISPR-Cas system. Nucleic Acids Res 2019; 47:5420-5428. [PMID: 30976796 PMCID: PMC6547453 DOI: 10.1093/nar/gkz269] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 03/31/2019] [Accepted: 04/04/2019] [Indexed: 12/26/2022] Open
Abstract
The Type VI-D CRISPR-Cas system employs an RNA-guided RNase Cas13d with minimal targeting constraints to combat viral infections. This CRISPR system contains RspWYL1 as a unique accessory protein that plays a key role in boosting its effector function on target RNAs, but the mechanism behind this RspWYL1-mediated stimulation remains completely unexplored. Through structural and biophysical approaches, we reveal that the full-length RspWYL1 possesses a novel three-domain architecture and preferentially binds ssRNA with high affinity. Specifically, the N-terminus of RspWYL1 harbors a ribbon-helix-helix motif reminiscent of transcriptional regulators; the central WYL domain of RspWYL1 displays a Sm-like β-barrel fold; and the C-terminal domain of RspWYL1 primarily contributes to the dimerization of RspWYL1 and may regulate the RspWYL1 function via a large conformational change. Collectively, this study provides a first glimpse into the complex mechanism behind the RspWYL1-dictated boosting of target ssRNA cleavage in the Type VI-D CRISPR-Cas system.
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Affiliation(s)
- Heng Zhang
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Cheng Dong
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Li Li
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
| | | | - Jinrong Min
- Structural Genomics Consortium, University of Toronto, Toronto, ON M5G 1L7, Canada
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
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Varble A, Marraffini LA. Three New Cs for CRISPR: Collateral, Communicate, Cooperate. Trends Genet 2019; 35:446-456. [PMID: 31036344 PMCID: PMC6525018 DOI: 10.1016/j.tig.2019.03.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/28/2019] [Accepted: 03/28/2019] [Indexed: 12/18/2022]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) loci and their associated (cas) genes provide protection against invading phages and plasmids in prokaryotes. Typically, short sequences are captured from the genome of the invader, integrated into the CRISPR locus, and transcribed into short RNAs that direct RNA-guided Cas nucleases to the nucleic acids of the invader for their degradation. Recent work in the field has revealed unexpected features of the CRISPR-Cas mechanism: (i) collateral, nonspecific, cleavage of host nucleic acids; (ii) secondary messengers that amplify the immune response; and (iii) immunosuppression of CRISPR targeting by phage-encoded inhibitors. Here, we review these new and exciting findings.
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Affiliation(s)
- Andrew Varble
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA.
| | - Luciano A Marraffini
- Laboratory of Bacteriology, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA; Howard Hughes Medical Institute, The Rockefeller University, 1230 York Ave, New York, NY 10065, USA.
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35
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Hou S, Brenes-Álvarez M, Reimann V, Alkhnbashi OS, Backofen R, Muro-Pastor AM, Hess WR. CRISPR-Cas systems in multicellular cyanobacteria. RNA Biol 2019; 16:518-529. [PMID: 29995583 PMCID: PMC6546389 DOI: 10.1080/15476286.2018.1493330] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 07/01/2018] [Accepted: 06/19/2018] [Indexed: 01/12/2023] Open
Abstract
Novel CRISPR-Cas systems possess substantial potential for genome editing and manipulation of gene expression. The types and numbers of CRISPR-Cas systems vary substantially between different organisms. Some filamentous cyanobacteria harbor > 40 different putative CRISPR repeat-spacer cassettes, while the number of cas gene instances is much lower. Here we addressed the types and diversity of CRISPR-Cas systems and of CRISPR-like repeat-spacer arrays in 171 publicly available genomes of multicellular cyanobacteria. The number of 1328 repeat-spacer arrays exceeded the total of 391 encoded Cas1 proteins suggesting a tendency for fragmentation or the involvement of alternative adaptation factors. The model cyanobacterium Anabaena sp. PCC 7120 contains only three cas1 genes but hosts three Class 1, possibly one Class 2 and five orphan repeat-spacer arrays, all of which exhibit crRNA-typical expression patterns suggesting active transcription, maturation and incorporation into CRISPR complexes. The CRISPR-Cas system within the element interrupting the Anabaena sp. PCC 7120 fdxN gene, as well as analogous arrangements in other strains, occupy the genetic elements that become excised during the differentiation-related programmed site-specific recombination. This fact indicates the propensity of these elements for the integration of CRISPR-cas systems and points to a previously not recognized connection. The gene all3613 resembling a possible Class 2 effector protein is linked to a short repeat-spacer array and a single tRNA gene, similar to its homologs in other cyanobacteria. The diversity and presence of numerous CRISPR-Cas systems in DNA elements that are programmed for homologous recombination make filamentous cyanobacteria a prolific resource for their study. Abbreviations: Cas: CRISPR associated sequences; CRISPR: Clustered Regularly Interspaced Short Palindromic Repeats; C2c: Class 2 candidate; SDR: small dispersed repeat; TSS: transcriptional start site; UTR: untranslated region.
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Affiliation(s)
- Shengwei Hou
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Manuel Brenes-Álvarez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Seville, Spain
| | - Viktoria Reimann
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
| | - Omer S. Alkhnbashi
- Bioinformatics group, Department of Computer Science, University of Freiburg, Freiburg, Germany
| | - Rolf Backofen
- Bioinformatics group, Department of Computer Science, University of Freiburg, Freiburg, Germany
- Center for Biological Systems Analysis (ZBSA), University of Freiburg, Freiburg, Germany
- BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany
| | - Alicia M. Muro-Pastor
- Bioinformatics group, Department of Computer Science, University of Freiburg, Freiburg, Germany
| | - Wolfgang R. Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Freiburg, Germany
- Freiburg Institute for Advanced Studies,University of Freiburg, Freiburg, Germany
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36
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O'Connell MR. Molecular Mechanisms of RNA Targeting by Cas13-containing Type VI CRISPR-Cas Systems. J Mol Biol 2019; 431:66-87. [PMID: 29940185 DOI: 10.1016/j.jmb.2018.06.029] [Citation(s) in RCA: 205] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/08/2018] [Accepted: 06/12/2018] [Indexed: 12/11/2022]
Abstract
Prokaryotic adaptive immune systems use Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) and CRISPR-associated (Cas) proteins for RNA-guided cleavage of foreign genetic elements. The focus of this review, Type VI CRISPR-Cas systems, contain a single protein, Cas13 (formerly C2c2) that when assembled with a CRISPR RNA (crRNA) forms a crRNA-guided RNA-targeting effector complex. Type VI CRISPR-Cas systems can be divided into four subtypes (A-D) based on Cas13 phylogeny. All Cas13 proteins studied to date possess two enzymatically distinct ribonuclease activities that are required for optimal interference. One RNase is responsible for pre-crRNA processing to form mature Type VI interference complexes, while the other RNase activity provided by the two Higher Eukaryotes and Prokaryotes Nucleotide-binding (HEPN) domains, is required for degradation of target-RNA during viral interference. In this review, I will compare and contrast what is known about the molecular architecture and behavior of Type VI (A-D) CRISPR-Cas13 interference complexes, how this allows them to carry out their RNA-targeting function, how Type VI accessory proteins are able to modulate Cas13 activity, and how together all of these features have led to the rapid development of a range of RNA-targeting applications. Throughout I will also discuss some of the outstanding questions regarding Cas13's molecular behavior, and its role in bacterial adaptive immunity and RNA-targeting applications.
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Affiliation(s)
- Mitchell R O'Connell
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA; Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
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Behler J, Vijay D, Hess WR, Akhtar MK. CRISPR-Based Technologies for Metabolic Engineering in Cyanobacteria. Trends Biotechnol 2018; 36:996-1010. [DOI: 10.1016/j.tibtech.2018.05.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/24/2018] [Accepted: 05/29/2018] [Indexed: 12/16/2022]
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Shah SA, Alkhnbashi OS, Behler J, Han W, She Q, Hess WR, Garrett RA, Backofen R. Comprehensive search for accessory proteins encoded with archaeal and bacterial type III CRISPR-cas gene cassettes reveals 39 new cas gene families. RNA Biol 2018; 16:530-542. [PMID: 29911924 PMCID: PMC6546367 DOI: 10.1080/15476286.2018.1483685] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A study was undertaken to identify conserved proteins that are encoded adjacent to cas gene cassettes of Type III CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats – CRISPR associated) interference modules. Type III modules have been shown to target and degrade dsDNA, ssDNA and ssRNA and are frequently intertwined with cofunctional accessory genes, including genes encoding CRISPR-associated Rossman Fold (CARF) domains. Using a comparative genomics approach, and defining a Type III association score accounting for coevolution and specificity of flanking genes, we identified and classified 39 new Type III associated gene families. Most archaeal and bacterial Type III modules were seen to be flanked by several accessory genes, around half of which did not encode CARF domains and remain of unknown function. Northern blotting and interference assays in Synechocystis confirmed that one particular non-CARF accessory protein family was involved in crRNA maturation. Non-CARF accessory genes were generally diverse, encoding nuclease, helicase, protease, ATPase, transporter and transmembrane domains with some encoding no known domains. We infer that additional families of non-CARF accessory proteins remain to be found. The method employed is scalable for potential application to metagenomic data once automated pipelines for annotation of CRISPR-Cas systems have been developed. All accessory genes found in this study are presented online in a readily accessible and searchable format for researchers to audit their model organism of choice: http://accessory.crispr.dk.
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Affiliation(s)
- Shiraz A Shah
- a Copenhagen Prospective Studies on Asthma in Childhood , Herlev and Gentofte Hospital, University of Copenhagen , Denmark.,d Danish Archaea Centre, Department of Biology , University of Copenhagen , Copenhagen N , Denmark
| | - Omer S Alkhnbashi
- b Freiburg Bioinformatics Group, Department of Computer Science , University of Freiburg , Freiburg , Germany
| | - Juliane Behler
- c Genetics and Experimental Bioinformatics, Faculty of Biology , University of Freiburg, Freiburg , Germany
| | - Wenyuan Han
- d Danish Archaea Centre, Department of Biology , University of Copenhagen , Copenhagen N , Denmark
| | - Qunxin She
- d Danish Archaea Centre, Department of Biology , University of Copenhagen , Copenhagen N , Denmark
| | - Wolfgang R Hess
- c Genetics and Experimental Bioinformatics, Faculty of Biology , University of Freiburg, Freiburg , Germany.,e Freiburg Institute for Advanced Studies , University of Freiburg , Freiburg , Germany
| | - Roger A Garrett
- d Danish Archaea Centre, Department of Biology , University of Copenhagen , Copenhagen N , Denmark
| | - Rolf Backofen
- b Freiburg Bioinformatics Group, Department of Computer Science , University of Freiburg , Freiburg , Germany.,f BIOSS Centre for Biological Signaling Studies , University of Freiburg , Freiburg , Germany
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39
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Yan WX, Chong S, Zhang H, Makarova KS, Koonin EV, Cheng DR, Scott DA. Cas13d Is a Compact RNA-Targeting Type VI CRISPR Effector Positively Modulated by a WYL-Domain-Containing Accessory Protein. Mol Cell 2018; 70:327-339.e5. [PMID: 29551514 PMCID: PMC5935466 DOI: 10.1016/j.molcel.2018.02.028] [Citation(s) in RCA: 298] [Impact Index Per Article: 49.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 02/21/2018] [Accepted: 02/23/2018] [Indexed: 12/21/2022]
Abstract
Bacterial class 2 CRISPR-Cas systems utilize a single RNA-guided protein effector to mitigate viral infection. We aggregated genomic data from multiple sources and constructed an expanded database of predicted class 2 CRISPR-Cas systems. A search for novel RNA-targeting systems identified subtype VI-D, encoding dual HEPN domain-containing Cas13d effectors and putative WYL-domain-containing accessory proteins (WYL1 and WYL-b1 through WYL-b5). The median size of Cas13d proteins is 190 to 300 aa smaller than that of Cas13a-Cas13c. Despite their small size, Cas13d orthologs from Eubacterium siraeum (Es) and Ruminococcus sp. (Rsp) are active in both CRISPR RNA processing and targeting, as well as collateral RNA cleavage, with no target-flanking sequence requirements. The RspWYL1 protein stimulates RNA cleavage by both EsCas13d and RspCas13d, demonstrating a common regulatory mechanism for divergent Cas13d orthologs. The small size, minimal targeting constraints, and modular regulation of Cas13d effectors further expands the CRISPR toolkit for RNA manipulation and detection.
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MESH Headings
- Amino Acid Sequence
- Bacterial Proteins/chemistry
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- CRISPR-Associated Proteins/chemistry
- CRISPR-Associated Proteins/genetics
- CRISPR-Associated Proteins/metabolism
- CRISPR-Cas Systems
- Clustered Regularly Interspaced Short Palindromic Repeats
- Databases, Genetic
- Escherichia coli/enzymology
- Escherichia coli/genetics
- Eubacterium/enzymology
- Eubacterium/genetics
- Gene Editing/methods
- Gene Expression Regulation, Bacterial
- Nucleic Acid Conformation
- Protein Domains
- Protein Structure, Secondary
- RNA Processing, Post-Transcriptional
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Guide, CRISPR-Cas Systems/genetics
- RNA, Guide, CRISPR-Cas Systems/metabolism
- Ruminococcus/enzymology
- Ruminococcus/genetics
- Structure-Activity Relationship
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Affiliation(s)
| | | | | | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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40
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Jesser R, Behler J, Benda C, Reimann V, Hess WR. Biochemical analysis of the Cas6-1 RNA endonuclease associated with the subtype I-D CRISPR-Cas system in Synechocystis sp. PCC 6803. RNA Biol 2018. [PMID: 29517395 DOI: 10.1080/15476286.2018.1447742] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Specialized RNA endonucleases are critical for efficient activity of the CRISPR-Cas defense mechanisms against invading DNA or RNA. Cas6-type enzymes are the RNA endonucleases in many type I and type III CRISPR-Cas systems. These enzymes are diverse and critical residues involved in the recognition and cleavage of RNA substrates are not universally conserved. Cas6 endonucleases associated with the CRISPR-Cas subtypes I-A, I-B, I-C, I-E and I-F, as well as III-B have been studied from three archaea and four bacteria thus far. However, until now information about subtype I-D specific Cas6 endonucleases has remained scarce. Here, we report the biochemical analysis of Cas6-1, which is specific for the crRNA maturation from the subtype I-D CRISPR-Cas system of Synechocystis sp. PCC 6803. Assays of turnover kinetics suggest a single turnover mechanism for Cas6-1. The mutation of conserved amino acids R29A, H32A-S33A and H51A revealed these as essential, whereas the parallel mutation of R175A-R176A led to a pronounced and the K155A mutation to a slight reduction in enzymatic activity. In contrast, the mutations R67A, R81A and K231A left the enzymatic activity unchanged. These results are in accordance with the predominant role of histidine residues in the active site and of positively charged residues in RNA binding. Nevertheless, the protein-RNA interaction site seems to differ from other known systems, since imidazole could not restore the mutated histidine site.
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Affiliation(s)
- Rabea Jesser
- a Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg , Schänzlestr. 1, Freiburg , Germany
| | - Juliane Behler
- a Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg , Schänzlestr. 1, Freiburg , Germany
| | - Christian Benda
- b Department of Structural Cell Biology , Max-Planck-Institute of Biochemistry , Am Klopferspitz 18, Martinsried , Germany
| | - Viktoria Reimann
- a Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg , Schänzlestr. 1, Freiburg , Germany
| | - Wolfgang R Hess
- a Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg , Schänzlestr. 1, Freiburg , Germany.,c Freiburg Institute for Advanced Studies, University of Freiburg , Albertstr. 19, Freiburg , Germany
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41
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Rübsam H, Kirsch F, Reimann V, Erban A, Kopka J, Hagemann M, Hess WR, Klähn S. The iron-stress activated RNA 1 (IsaR1) coordinates osmotic acclimation and iron starvation responses in the cyanobacterium Synechocystis sp. PCC 6803. Environ Microbiol 2018; 20:2757-2768. [PMID: 29468839 DOI: 10.1111/1462-2920.14079] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 02/18/2018] [Indexed: 11/28/2022]
Abstract
In nature, microorganisms are exposed to multiple stress factors in parallel. Here, we investigated the response of the model cyanobacterium Synechocystis sp. PCC 6803 to simultaneous iron limitation and osmotic stresses. Iron is a major limiting factor for bacterial and phytoplankton growth in most environments. Thus, bacterial iron homeostasis is tightly regulated. In Synechocystis, it is mediated mainly by the transcriptional regulator FurA and the iron-stress activated RNA 1 (IsaR1). IsaR1 is an important riboregulator that affects the acclimation of the photosynthetic apparatus to iron starvation in multiple ways. Upon increases in salinity, Synechocystis responds by accumulating the compatible solute glucosylglycerol (GG). We show that IsaR1 overexpression causes a reduction in the de novo GG synthesis rate upon salt shock. We verified the direct interaction between IsaR1 and the 5'UTR of the ggpS mRNA, which in turn drastically reduced the de novo synthesis of the key enzyme for GG synthesis, glucosylglycerol phosphate synthase (GgpS). Thus, IsaR1 specifically interferes with the salt acclimation process in Synechocystis, in addition to its primary regulatory function. Moreover, the salt-stimulated GgpS production became reduced under parallel iron limitation in WT - an effect which is, however, attenuated in an isaR1 deletion strain. Hence, IsaR1 is involved in the integration of the responses to different environmental perturbations and slows the osmotic adaptation process in cells suffering from parallel iron starvation.
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Affiliation(s)
- Henriette Rübsam
- Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, University of Freiburg, D-79104 Freiburg, Germany
| | - Friedrich Kirsch
- Plant Physiology department, A.-Einstein-Str. 3, University of Rostock, Institute of Biological Sciences, D-18059 Rostock, Germany
| | - Viktoria Reimann
- Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, University of Freiburg, D-79104 Freiburg, Germany
| | - Alexander Erban
- Department of Molecular Physiology: Applied Metabolome Analysis, Am Mühlenberg 1, Max-Planck-Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Joachim Kopka
- Department of Molecular Physiology: Applied Metabolome Analysis, Am Mühlenberg 1, Max-Planck-Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Martin Hagemann
- Plant Physiology department, A.-Einstein-Str. 3, University of Rostock, Institute of Biological Sciences, D-18059 Rostock, Germany
| | - Wolfgang R Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, University of Freiburg, D-79104 Freiburg, Germany
| | - Stephan Klähn
- Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, University of Freiburg, D-79104 Freiburg, Germany
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42
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Teikari JE, Hou S, Wahlsten M, Hess WR, Sivonen K. Comparative Genomics of the Baltic Sea Toxic Cyanobacteria Nodularia spumigena UHCC 0039 and Its Response to Varying Salinity. Front Microbiol 2018; 9:356. [PMID: 29568283 PMCID: PMC5853447 DOI: 10.3389/fmicb.2018.00356] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 02/14/2018] [Indexed: 11/13/2022] Open
Abstract
Salinity is an important abiotic factor controlling the distribution and abundance of Nodularia spumigena, the dominating diazotrophic and toxic phototroph, in the brackish water cyanobacterial blooms of the Baltic Sea. To expand the available genomic information for brackish water cyanobacteria, we sequenced the isolate Nodularia spumigena UHCC 0039 using an Illumina-SMRT hybrid sequencing approach, revealing a chromosome of 5,294,286 base pairs (bp) and a single plasmid of 92,326 bp. Comparative genomics in Nostocales showed pronounced genetic similarity among Nodularia spumigena strains evidencing their short evolutionary history. The studied Baltic Sea strains share similar sets of CRISPR-Cas cassettes and a higher number of insertion sequence (IS) elements compared to Nodularia spumigena CENA596 isolated from a shrimp production pond in Brazil. Nodularia spumigena UHCC 0039 proliferated similarly at three tested salinities, whereas the lack of salt inhibited its growth and triggered transcriptome remodeling, including the up-regulation of five sigma factors and the down-regulation of two other sigma factors, one of which is specific for strain UHCC 0039. Down-regulated genes additionally included a large genetic region for the synthesis of two yet unidentified natural products. Our results indicate a remarkable plasticity of the Nodularia salinity acclimation, and thus salinity strongly impacts the intensity and distribution of cyanobacterial blooms in the Baltic Sea.
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Affiliation(s)
- Jonna E Teikari
- Department of Microbiology, University of Helsinki, Helsinki, Finland
| | - Shengwei Hou
- Genetics and Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Matti Wahlsten
- Department of Microbiology, University of Helsinki, Helsinki, Finland
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Freiburg, Germany.,Freiburg Institute for Advanced Studies, University of Freiburg, Freiburg, Germany
| | - Kaarina Sivonen
- Department of Microbiology, University of Helsinki, Helsinki, Finland
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43
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Abstract
CRISPR-Cas genome editing technologies have revolutionized modern molecular biology by making targeted DNA edits simple and scalable. These technologies are developed by domesticating naturally occurring microbial adaptive immune systems that display wide diversity of functionality for targeted nucleic acid cleavage. Several CRISPR-Cas single effector enzymes have been characterized and engineered for use in mammalian cells. The unique properties of the single effector enzymes can make a critical difference in experimental use or targeting specificity. This review describes known single effector enzymes and discusses their use in genome engineering applications.
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Affiliation(s)
- Neena K. Pyzocha
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, United States
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Sidi Chen
- Department of Genetics, Yale University, 333 Cedar Street, New Haven, Connecticut 06510, United States
- System Biology Institute, 850 West Campus Drive, ISTC 361, West Haven, Connecticut 06516, United States
- MCGD Program, Yale University, 333 Cedar Street, New Haven, Connecticut 06510, United States
- Immunobiology Program, Yale University, 300 Cedar Street, New Haven, Connecticut 06520, United States
- Comprehensive Cancer Center, Yale University, New Haven, Connecticut 06510, United States
- Stem Cell Center, Yale University, New Haven, Connecticut 06510, United States
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44
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The host-encoded RNase E endonuclease as the crRNA maturation enzyme in a CRISPR-Cas subtype III-Bv system. Nat Microbiol 2018; 3:367-377. [PMID: 29403013 DOI: 10.1038/s41564-017-0103-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 12/20/2017] [Indexed: 02/08/2023]
Abstract
Specialized RNA endonucleases for the maturation of clustered regularly interspaced short palindromic repeat (CRISPR)-derived RNAs (crRNAs) are critical in CRISPR-CRISPR-associated protein (Cas) defence mechanisms. The Cas6 and Cas5d enzymes are the RNA endonucleases in many class 1 CRISPR-Cas systems. In some class 2 systems, maturation and effector functions are combined within a single enzyme or maturation proceeds through the combined actions of RNase III and trans-activating CRISPR RNAs (tracrRNAs). Three separate CRISPR-Cas systems exist in the cyanobacterium Synechocystis sp. PCC 6803. Whereas Cas6-type enzymes act in two of these systems, the third, which is classified as subtype III-B variant (III-Bv), lacks cas6 homologues. Instead, the maturation of crRNAs proceeds through the activity of endoribonuclease E, leaving unusual 13- and 14-nucleotide-long 5'-handles. Overexpression of RNase E leads to overaccumulation and knock-down to the reduced accumulation of crRNAs in vivo, suggesting that RNase E is the limiting factor for CRISPR complex formation. Recognition by RNase E depends on a stem-loop in the CRISPR repeat, whereas base substitutions at the cleavage site trigger the appearance of secondary products, consistent with a two-step recognition and cleavage mechanism. These results suggest the adaptation of an otherwise very conserved housekeeping enzyme to accommodate new substrates and illuminate the impressive plasticity of CRISPR-Cas systems that enables them to function in particular genomic environments.
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45
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Andis NM, Sausen CW, Alladin A, Bochman ML. The WYL Domain of the PIF1 Helicase from the Thermophilic Bacterium Thermotoga elfii is an Accessory Single-Stranded DNA Binding Module. Biochemistry 2018; 57:1108-1118. [PMID: 29341597 DOI: 10.1021/acs.biochem.7b01233] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PIF1 family helicases are conserved from bacteria to man. With the exception of the well-studied yeast PIF1 helicases (e.g., ScPif1 and ScRrm3), however, very little is known about how these enzymes help maintain genome stability. Indeed, we lack a basic understanding of the protein domains found N- and C-terminal to the characteristic central PIF1 helicase domain in these proteins. Here, using chimeric constructs, we show that the ScPif1 and ScRrm3 helicase domains are interchangeable and that the N-terminus of ScRrm3 is important for its function in vivo. This suggests that PIF1 family helicases evolved functional modules fused to a generic motor domain. To investigate this hypothesis, we characterized the biochemical activities of the PIF1 helicase from the thermophilic bacterium Thermotoga elfii (TePif1), which contains a C-terminal WYL domain of unknown function. Like helicases from other thermophiles, recombinant TePif1 was easily prepared, thermostable in vitro, and displayed activities similar to its eukaryotic homologues. We also found that the WYL domain was necessary for high-affinity single-stranded DNA (ssDNA) binding and affected both ATPase and helicase activities. Deleting the WYL domain from TePif1 or mutating conserved residues in the predicted ssDNA binding site uncoupled ATPase activity and DNA unwinding, leading to higher rates of ATP hydrolysis but less efficient DNA helicase activity. Our findings suggest that the domains of unknown function found in eukaryotic PIF1 helicases may also confer functional specificity and additional activities to these enzymes, which should be investigated in future work.
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Affiliation(s)
- Nicholas M Andis
- Molecular and Cellular Biochemistry Department, Indiana University , Bloomington, Indiana 47405, United States
| | - Christopher W Sausen
- Molecular and Cellular Biochemistry Department, Indiana University , Bloomington, Indiana 47405, United States
| | - Ashna Alladin
- Molecular and Cellular Biochemistry Department, Indiana University , Bloomington, Indiana 47405, United States
| | - Matthew L Bochman
- Molecular and Cellular Biochemistry Department, Indiana University , Bloomington, Indiana 47405, United States
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46
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Kirsch F, Pade N, Klähn S, Hess WR, Hagemann M. The glucosylglycerol-degrading enzyme GghA is involved in acclimation to fluctuating salinities by the cyanobacterium Synechocystis sp. strain PCC 6803. MICROBIOLOGY-SGM 2017; 163:1319-1328. [PMID: 28857041 DOI: 10.1099/mic.0.000518] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The ggpS gene, which encodes the key enzyme for the synthesis of the compatible solute glucosylglycerol (GG), has a promoter region that overlaps with the upstream-located gene slr1670 in the cyanobacterium Synechocystissp. PCC 6803. Like ggpS, the slr1670 gene is salt-induced and encodes a putative glucosylhydrolase. A mutant strain with a slr1670 deletion was generated and found to be unable to adapt the internal GG concentrations in response to changes in external salinities. Whereas cells of the wild-type reduced the internal pool of GG when exposed to gradual and abrupt hypo-osmotic treatments, or when the compatible solute trehalose was added to the growth medium, the internal GG pool of ∆slr1670 mutant cells remained unchanged. These findings indicated that the protein Slr1670 is involved in GG breakdown. The biochemical activity of this GG-hydrolase enzyme was verified using recombinant Slr1670 protein, which split GG into glucose and glycerol. These results validate that Slr1670, which was named GghA, acts as a GG hydrolase. GghA is involved in GG turnover in fluctuating salinities, and similar proteins are found in the genomes of other GG-synthesizing cyanobacteria.
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Affiliation(s)
- Friedrich Kirsch
- University of Rostock, Institute for Biowissenschaften, Abt. Pflanzenphysiologie, A.-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Nadin Pade
- University of Rostock, Institute for Biowissenschaften, Abt. Pflanzenphysiologie, A.-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Stephan Klähn
- Genetics and Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics, Institute of Biology III, University of Freiburg, Freiburg, Germany
| | - Martin Hagemann
- University of Rostock, Institute for Biowissenschaften, Abt. Pflanzenphysiologie, A.-Einstein-Str. 3, D-18059 Rostock, Germany
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Srivastava A, Brilisauer K, Rai AK, Ballal A, Forchhammer K, Tripathi AK. Down-Regulation of the Alternative Sigma Factor SigJ Confers a Photoprotective Phenotype to Anabaena PCC 7120. PLANT & CELL PHYSIOLOGY 2017; 58:287-297. [PMID: 27837096 DOI: 10.1093/pcp/pcw188] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 10/28/2016] [Indexed: 06/06/2023]
Abstract
Alternative sigma factors belonging to Group 3 are thought to play an important role in the adaptation of cyanobacteria to environmental challenges by altering expression of genes needed for coping with such stresses. In this study, the role of an alternative sigma factor, SigJ, was analyzed in the filamentous nitrogen-fixing cyanobacterium, Anabaena sp. PCC 7120 by knocking down the expression of the sigJ gene (alr0277) employing an antisense RNA-mediated approach. In the absence of any stress, the knock-down (KD0277) or the wild-type strain both grew similarly. Upon exposure to high-intensity light, KD0277 showed substantially reduced bleaching of its pigments, higher photosynthetic activity and consequently better survival than the wild type. KD0277 also showed an enhanced accumulation of two carotenoids, which were identified as myxoxanthophyll and keto-myxoxanthophyll. Further, KD0277 was more tolerant to ammonium-triggered photodamage than the wild type. Moreover, PSII was better protected against photodamage in KD0277 than in the wild type. Down-regulation of sigJ in Anabaena PCC 7120, however, reduced its ability to cope with desiccation. This study demonstrates that down-regulation of the sigJ gene in Anabaena PCC 7120 differentially affects its ability to tolerate two environmentally relevant stresses, i.e. high-intensity light and desiccation.
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Affiliation(s)
- Amit Srivastava
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Klaus Brilisauer
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle, Tübingen, Germany
| | - Ashutosh K Rai
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
| | - Anand Ballal
- Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai, India
- Homi Bhabha National Institute, Anushakti Nagar, Mumbai, India
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle, Tübingen, Germany
| | - Anil K Tripathi
- School of Biotechnology, Institute of Science, Banaras Hindu University, Varanasi, India
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Al-Haj L, Lui YT, Abed RMM, Gomaa MA, Purton S. Cyanobacteria as Chassis for Industrial Biotechnology: Progress and Prospects. Life (Basel) 2016; 6:life6040042. [PMID: 27916886 PMCID: PMC5198077 DOI: 10.3390/life6040042] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/13/2016] [Accepted: 11/25/2016] [Indexed: 12/24/2022] Open
Abstract
Cyanobacteria hold significant potential as industrial biotechnology (IB) platforms for the production of a wide variety of bio-products ranging from biofuels such as hydrogen, alcohols and isoprenoids, to high-value bioactive and recombinant proteins. Underpinning this technology, are the recent advances in cyanobacterial “omics” research, the development of improved genetic engineering tools for key species, and the emerging field of cyanobacterial synthetic biology. These approaches enabled the development of elaborate metabolic engineering programs aimed at creating designer strains tailored for different IB applications. In this review, we provide an overview of the current status of the fields of cyanobacterial omics and genetic engineering with specific focus on the current molecular tools and technologies that have been developed in the past five years. The paper concludes by giving insights on future commercial applications of cyanobacteria and highlights the challenges that need to be addressed in order to make cyanobacterial industrial biotechnology more feasible in the near future.
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Affiliation(s)
- Lamya Al-Haj
- Biology Department, College of Science, Sultan Qaboos University, Al-Khoud, P.O. Box 36, Muscat 123, Oman.
| | - Yuen Tin Lui
- Institute of Structural & Molecular Biology, University College London, London WC1E 6BT, UK.
| | - Raeid M M Abed
- Biology Department, College of Science, Sultan Qaboos University, Al-Khoud, P.O. Box 36, Muscat 123, Oman.
| | - Mohamed A Gomaa
- Biology Department, College of Science, Sultan Qaboos University, Al-Khoud, P.O. Box 36, Muscat 123, Oman.
| | - Saul Purton
- Institute of Structural & Molecular Biology, University College London, London WC1E 6BT, UK.
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Baumgartner D, Kopf M, Klähn S, Steglich C, Hess WR. Small proteins in cyanobacteria provide a paradigm for the functional analysis of the bacterial micro-proteome. BMC Microbiol 2016; 16:285. [PMID: 27894276 PMCID: PMC5126843 DOI: 10.1186/s12866-016-0896-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 11/14/2016] [Indexed: 12/21/2022] Open
Abstract
Background Despite their versatile functions in multimeric protein complexes, in the modification of enzymatic activities, intercellular communication or regulatory processes, proteins shorter than 80 amino acids (μ-proteins) are a systematically underestimated class of gene products in bacteria. Photosynthetic cyanobacteria provide a paradigm for small protein functions due to extensive work on the photosynthetic apparatus that led to the functional characterization of 19 small proteins of less than 50 amino acids. In analogy, previously unstudied small ORFs with similar degrees of conservation might encode small proteins of high relevance also in other functional contexts. Results Here we used comparative transcriptomic information available for two model cyanobacteria, Synechocystis sp. PCC 6803 and Synechocystis sp. PCC 6714 for the prediction of small ORFs. We found 293 transcriptional units containing candidate small ORFs ≤80 codons in Synechocystis sp. PCC 6803, also including the known mRNAs encoding small proteins of the photosynthetic apparatus. From these transcriptional units, 146 are shared between the two strains, 42 are shared with the higher plant Arabidopsis thaliana and 25 with E. coli. To verify the existence of the respective μ-proteins in vivo, we selected five genes as examples to which a FLAG tag sequence was added and re-introduced them into Synechocystis sp. PCC 6803. These were the previously annotated gene ssr1169, two newly defined genes norf1 and norf4, as well as nsiR6(nitrogen stress-induced RNA 6) and hliR1(high light-inducible RNA 1) , which originally were considered non-coding. Upon activation of expression via the Cu2+.responsive petE promoter or from the native promoters, all five proteins were detected in Western blot experiments. Conclusions The distribution and conservation of these five genes as well as their regulation of expression and the physico-chemical properties of the encoded proteins underline the likely great bandwidth of small protein functions in bacteria and makes them attractive candidates for functional studies.
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Affiliation(s)
- Desiree Baumgartner
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Matthias Kopf
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104, Freiburg, Germany.,Present Address: Molecular Health GmbH, Kurfürsten-Anlage 21, 69115, Heidelberg, Germany
| | - Stephan Klähn
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Claudia Steglich
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Wolfgang R Hess
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, D-79104, Freiburg, Germany.
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Type II Toxin-Antitoxin Systems in the Unicellular Cyanobacterium Synechocystis sp. PCC 6803. Toxins (Basel) 2016; 8:toxins8070228. [PMID: 27455323 PMCID: PMC4963859 DOI: 10.3390/toxins8070228] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 07/11/2016] [Indexed: 12/03/2022] Open
Abstract
Bacterial toxin–antitoxin (TA) systems are genetic elements, which are encoded by plasmid as well as chromosomal loci. They mediate plasmid and genomic island maintenance through post-segregational killing mechanisms but may also have milder effects, acting as mobile stress response systems that help certain cells of a population in persisting adverse growth conditions. Very few cyanobacterial TA system have been characterized thus far. In this work, we focus on the cyanobacterium Synechocystis 6803, a widely used model organism. We expand the number of putative Type II TA systems from 36 to 69 plus seven stand-alone components. Forty-seven TA pairs are located on the chromosome and 22 are plasmid-located. Different types of toxins are associated with various antitoxins in a mix and match principle. According to protein domains and experimental data, 81% of all toxins in Synechocystis 6803 likely exhibit RNase activity, suggesting extensive potential for toxicity-related RNA degradation and toxin-mediated transcriptome remodeling. Of particular interest is the Ssr8013–Slr8014 system encoded on plasmid pSYSG, which is part of a larger defense island or the pSYSX system Slr6056–Slr6057, which is linked to a bacterial ubiquitin-like system. Consequently, Synechocystis 6803 is one of the most prolific sources of new information about these genetic elements.
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