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Archaea as a Model System for Molecular Biology and Biotechnology. Biomolecules 2023; 13:biom13010114. [PMID: 36671499 PMCID: PMC9855744 DOI: 10.3390/biom13010114] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/29/2022] [Accepted: 01/04/2023] [Indexed: 01/09/2023] Open
Abstract
Archaea represents the third domain of life, displaying a closer relationship with eukaryotes than bacteria. These microorganisms are valuable model systems for molecular biology and biotechnology. In fact, nowadays, methanogens, halophiles, thermophilic euryarchaeota, and crenarchaeota are the four groups of archaea for which genetic systems have been well established, making them suitable as model systems and allowing for the increasing study of archaeal genes' functions. Furthermore, thermophiles are used to explore several aspects of archaeal biology, such as stress responses, DNA replication and repair, transcription, translation and its regulation mechanisms, CRISPR systems, and carbon and energy metabolism. Extremophilic archaea also represent a valuable source of new biomolecules for biological and biotechnological applications, and there is growing interest in the development of engineered strains. In this review, we report on some of the most important aspects of the use of archaea as a model system for genetic evolution, the development of genetic tools, and their application for the elucidation of the basal molecular mechanisms in this domain of life. Furthermore, an overview on the discovery of new enzymes of biotechnological interest from archaea thriving in extreme environments is reported.
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2
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Bornemann TLV, Adam PS, Turzynski V, Schreiber U, Figueroa-Gonzalez PA, Rahlff J, Köster D, Schmidt TC, Schunk R, Krauthausen B, Probst AJ. Genetic diversity in terrestrial subsurface ecosystems impacted by geological degassing. Nat Commun 2022; 13:284. [PMID: 35022403 PMCID: PMC8755723 DOI: 10.1038/s41467-021-27783-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 12/02/2021] [Indexed: 12/30/2022] Open
Abstract
Earth’s mantle releases 38.7 ± 2.9 Tg/yr CO2 along with other reduced and oxidized gases to the atmosphere shaping microbial metabolism at volcanic sites across the globe, yet little is known about its impact on microbial life under non-thermal conditions. Here, we perform comparative metagenomics coupled to geochemical measurements of deep subsurface fluids from a cold-water geyser driven by mantle degassing. Key organisms belonging to uncultivated Candidatus Altiarchaeum show a global biogeographic pattern and site-specific adaptations shaped by gene loss and inter-kingdom horizontal gene transfer. Comparison of the geyser community to 16 other publicly available deep subsurface sites demonstrate a conservation of chemolithoautotrophic metabolism across sites. In silico replication measures suggest a linear relationship of bacterial replication with ecosystems depth with the exception of impacted sites, which show near surface characteristics. Our results suggest that subsurface ecosystems affected by geological degassing are hotspots for microbial life in the deep biosphere. Geological degassing can impact subsurface metabolism. Here, the authors describe microbial communities from a cold-water geyser are described and compared with other deep subsurface sites, finding a key role for an uncultivated archaeon.
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Affiliation(s)
- Till L V Bornemann
- Environmental Microbiology and Biotechnology, Faculty of Chemistry, University Duisburg-Essen, Essen, Germany
| | - Panagiotis S Adam
- Environmental Microbiology and Biotechnology, Faculty of Chemistry, University Duisburg-Essen, Essen, Germany
| | - Victoria Turzynski
- Environmental Microbiology and Biotechnology, Faculty of Chemistry, University Duisburg-Essen, Essen, Germany
| | - Ulrich Schreiber
- Department of Geology, University Duisburg-Essen, Essen, Germany
| | | | - Janina Rahlff
- Environmental Microbiology and Biotechnology, Faculty of Chemistry, University Duisburg-Essen, Essen, Germany.,Centre for Ecology and Evolution in Microbial Model Systems (EEMiS), Department of Biology and Environmental Science, Linneaus University, Kalmar, Sweden
| | - Daniel Köster
- Instrumental Analytical Chemistry and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Essen, Germany
| | - Torsten C Schmidt
- Instrumental Analytical Chemistry and Centre for Water and Environmental Research (ZWU), University of Duisburg-Essen, Essen, Germany.,Centre of Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstraße 5, Essen, Germany
| | | | - Bernhard Krauthausen
- Institute of Applied Geosciences, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Alexander J Probst
- Environmental Microbiology and Biotechnology, Faculty of Chemistry, University Duisburg-Essen, Essen, Germany. .,Centre of Water and Environmental Research (ZWU), University of Duisburg-Essen, Universitätsstraße 5, Essen, Germany.
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Ecological Dichotomies Arise in Microbial Communities Due to Mixing of Deep Hydrothermal Waters and Atmospheric Gas in a Circumneutral Hot Spring. Appl Environ Microbiol 2021; 87:e0159821. [PMID: 34586901 PMCID: PMC8579995 DOI: 10.1128/aem.01598-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Little is known of how the confluence of subsurface and surface processes influences the assembly and habitability of hydrothermal ecosystems. To address this knowledge gap, the geochemical and microbial composition of a high-temperature, circumneutral hot spring in Yellowstone National Park was examined to identify the sources of solutes and their effect on the ecology of microbial inhabitants. Metagenomic analysis showed that populations comprising planktonic and sediment communities are archaeal dominated, are dependent on chemical energy (chemosynthetic), share little overlap in their taxonomic composition, and are differentiated by their inferred use of/tolerance to oxygen and mode of carbon metabolism. The planktonic community is dominated by putative aerobic/aerotolerant autotrophs, while the taxonomic composition of the sediment community is more evenly distributed and comprised of anaerobic heterotrophs. These observations are interpreted to reflect sourcing of the spring by anoxic, organic carbon-limited subsurface hydrothermal fluids and ingassing of atmospheric oxygen that selects for aerobic/aerotolerant organisms that have autotrophic capabilities in the water column. Autotrophy and consumption of oxygen by the planktonic community may influence the assembly of the anaerobic and heterotrophic sediment community. Support for this inference comes from higher estimated rates of genome replication in planktonic populations than sediment populations, indicating faster growth in planktonic populations. Collectively, these observations provide new insight into how mixing of subsurface waters and atmospheric oxygen create dichotomy in the ecology of hot spring communities and suggest that planktonic and sediment communities may have been less differentiated taxonomically and functionally prior to the rise of oxygen at ∼2.4 billion years ago (Gya). IMPORTANCE Understanding the source and availability of energy capable of supporting life in hydrothermal environments is central to predicting the ecology of microbial life on early Earth when volcanic activity was more widespread. Little is known of the substrates supporting microbial life in circumneutral to alkaline springs, despite their relevance to early Earth habitats. Using metagenomic and informatics approaches, water column and sediment habitats in a representative circumneutral hot spring in Yellowstone were shown to be dichotomous, with the former largely hosting aerobic/aerotolerant autotrophs and the latter primarily hosting anaerobic heterotrophs. This dichotomy is attributed to influx of atmospheric oxygen into anoxic deep hydrothermal spring waters. These results indicate that the ecology of microorganisms in circumneutral alkaline springs sourced by deep hydrothermal fluids was different prior to the rise of atmospheric oxygen ∼2.4 Gya, with planktonic and sediment communities likely to be less differentiated than contemporary circumneutral hot springs.
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Duprey A, Groisman EA. The regulation of DNA supercoiling across evolution. Protein Sci 2021; 30:2042-2056. [PMID: 34398513 PMCID: PMC8442966 DOI: 10.1002/pro.4171] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/04/2021] [Accepted: 08/04/2021] [Indexed: 11/11/2022]
Abstract
DNA supercoiling controls a variety of cellular processes, including transcription, recombination, chromosome replication, and segregation, across all domains of life. As a physical property, DNA supercoiling alters the double helix structure by under- or over-winding it. Intriguingly, the evolution of DNA supercoiling reveals both similarities and differences in its properties and regulation across the three domains of life. Whereas all organisms exhibit local, constrained DNA supercoiling, only bacteria and archaea exhibit unconstrained global supercoiling. DNA supercoiling emerges naturally from certain cellular processes and can also be changed by enzymes called topoisomerases. While structurally and mechanistically distinct, topoisomerases that dissipate excessive supercoils exist in all domains of life. By contrast, topoisomerases that introduce positive or negative supercoils exist only in bacteria and archaea. The abundance of topoisomerases is also transcriptionally and post-transcriptionally regulated in domain-specific ways. Nucleoid-associated proteins, metabolites, and physicochemical factors influence DNA supercoiling by acting on the DNA itself or by impacting the activity of topoisomerases. Overall, the unique strategies that organisms have evolved to regulate DNA supercoiling hold significant therapeutic potential, such as bactericidal agents that target bacteria-specific processes or anticancer drugs that hinder abnormal DNA replication by acting on eukaryotic topoisomerases specialized in this process. The investigation of DNA supercoiling therefore reveals general principles, conserved mechanisms, and kingdom-specific variations relevant to a wide range of biological questions.
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Affiliation(s)
- Alexandre Duprey
- Department of Microbial PathogenesisYale School of MedicineNew HavenConnecticutUSA
| | - Eduardo A. Groisman
- Department of Microbial PathogenesisYale School of MedicineNew HavenConnecticutUSA
- Yale Microbial Sciences InstituteWest HavenConnecticutUSA
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5
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Pérez-Arnaiz P, Dattani A, Smith V, Allers T. Haloferax volcanii-a model archaeon for studying DNA replication and repair. Open Biol 2020; 10:200293. [PMID: 33259746 PMCID: PMC7776575 DOI: 10.1098/rsob.200293] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/09/2020] [Indexed: 12/16/2022] Open
Abstract
The tree of life shows the relationship between all organisms based on their common ancestry. Until 1977, it comprised two major branches: prokaryotes and eukaryotes. Work by Carl Woese and other microbiologists led to the recategorization of prokaryotes and the proposal of three primary domains: Eukarya, Bacteria and Archaea. Microbiological, genetic and biochemical techniques were then needed to study the third domain of life. Haloferax volcanii, a halophilic species belonging to the phylum Euryarchaeota, has provided many useful tools to study Archaea, including easy culturing methods, genetic manipulation and phenotypic screening. This review will focus on DNA replication and DNA repair pathways in H. volcanii, how this work has advanced our knowledge of archaeal cellular biology, and how it may deepen our understanding of bacterial and eukaryotic processes.
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Affiliation(s)
| | | | | | - Thorsten Allers
- School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
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Shmakov SA, Utkina I, Wolf YI, Makarova KS, Severinov KV, Koonin EV. CRISPR Arrays Away from cas Genes. CRISPR J 2020; 3:535-549. [PMID: 33346707 PMCID: PMC7757702 DOI: 10.1089/crispr.2020.0062] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
CRISPR-Cas systems typically consist of a CRISPR array and cas genes that are organized in one or more operons. However, a substantial fraction of CRISPR arrays are not adjacent to cas genes. Definitive identification of such isolated CRISPR arrays runs into the problem of false-positives, with unrelated types of repetitive sequences mimicking CRISPR. We developed a computational pipeline to eliminate false CRISPR predictions and found that up to 25% of the CRISPR arrays in complete bacterial and archaeal genomes are located away from cas genes. Most of the repeats in these isolated arrays are identical to repeats in cas-adjacent CRISPR arrays in the same or closely related genomes, indicating an evolutionary relationship between isolated arrays and arrays in typical CRISPR-cas loci. The spacers in isolated CRISPR arrays show nearly as many matches to viral genomes as spacers from complete CRISPR-cas loci, suggesting that the isolated arrays were either functionally active recently or continue to function. Reconstruction of evolutionary events in closely related bacterial genomes suggests three routes of evolution of isolated CRISPR arrays: (1) loss of cas genes in a CRISPR-cas locus, (2) de novo generation of arrays from off-target spacer integration into sequences resembling the corresponding repeats, and (3) transfer by mobile genetic elements. Both combination of de novo emerging arrays with cas genes and regain of cas genes by isolated arrays via recombination likely contribute to functional diversification in CRISPR-Cas evolution.
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Affiliation(s)
- Sergey A. Shmakov
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA; Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
| | - Irina Utkina
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA; Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
- Skolkovo Institute of Science and Technology, Skolkovo, Russia; Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
- The Hospital for Sick Children, University of Toronto, Toronto, Canada; Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
| | - Yuri I. Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA; Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
| | - Kira S. Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA; Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
| | - Konstantin V. Severinov
- Institute of Molecular Genetics, Russian Academy of Sciences, Moscow, Russia; and Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
- Waksman Institute of Microbiology, Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
| | - Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA; Rutgers, State University of New Jersey, Piscataway, New Jersey, USA
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7
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de Araujo CB, da Cunha JPC, Inada DT, Damasceno J, Lima ARJ, Hiraiwa P, Marques C, Gonçalves E, Nishiyama-Junior MY, McCulloch R, Elias MC. Replication origin location might contribute to genetic variability in Trypanosoma cruzi. BMC Genomics 2020; 21:414. [PMID: 32571205 PMCID: PMC7310030 DOI: 10.1186/s12864-020-06803-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 06/05/2020] [Indexed: 11/29/2022] Open
Abstract
Background DNA replication in trypanosomatids operates in a uniquely challenging environment, since most of their genomes are constitutively transcribed. Trypanosoma cruzi, the etiological agent of Chagas disease, presents high variability in both chromosomes size and copy number among strains, though the underlying mechanisms are unknown. Results Here we have mapped sites of DNA replication initiation across the T. cruzi genome using Marker Frequency Analysis, which has previously only been deployed in two related trypanosomatids. The putative origins identified in T. cruzi show a notable enrichment of GC content, a preferential position at subtelomeric regions, coinciding with genes transcribed towards the telomeres, and a pronounced enrichment within coding DNA sequences, most notably in genes from the Dispersed Gene Family 1 (DGF-1). Conclusions These findings suggest a scenario where collisions between DNA replication and transcription are frequent, leading to increased genetic variability, as seen by the increase SNP levels at chromosome subtelomeres and in DGF-1 genes containing putative origins.
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Affiliation(s)
- Christiane Bezerra de Araujo
- Laboratório de Ciclo Celular, Instituto Butantan, São Paulo, Brazil.,Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil
| | - Julia Pinheiro Chagas da Cunha
- Laboratório de Ciclo Celular, Instituto Butantan, São Paulo, Brazil. .,Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil.
| | - Davi Toshio Inada
- Laboratório de Ciclo Celular, Instituto Butantan, São Paulo, Brazil.,Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil
| | - Jeziel Damasceno
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Alex Ranieri Jerônimo Lima
- Laboratório de Tecnologia Biomolecular - Bioinformática, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | | | - Catarina Marques
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Evonnildo Gonçalves
- Laboratório de Tecnologia Biomolecular - Bioinformática, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Milton Yutaka Nishiyama-Junior
- Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil.,Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, São Paulo, Brazil
| | - Richard McCulloch
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Maria Carolina Elias
- Laboratório de Ciclo Celular, Instituto Butantan, São Paulo, Brazil. .,Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil.
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8
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Durán-Viseras A, Andrei AŞ, Vera-Gargallo B, Ghai R, Sánchez-Porro C, Ventosa A. Culturomics-based genomics sheds light on the ecology of the new haloarchaeal genus Halosegnis. Environ Microbiol 2020; 23:3418-3434. [PMID: 32410366 DOI: 10.1111/1462-2920.15082] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 12/22/2022]
Abstract
The development of culture-independent techniques has revolutionized our understanding of microbial ecology, especially through the illustration of the vast gap between the environmentally abundant microbial diversity and that accessible through cultivation. However, culture-based approaches are not only crucial for understanding the evolutionary, metabolic and ecological milieu of microbial diversity but also for the development of novel biotechnological applications. In this study, we used a culturomics-based approach in order to isolate novel microbial taxa from hypersaline environments (i.e. Isla Cristina and Isla Bacuta salterns in Huelva, Spain). We managed to obtain axenic cultures of four haloarchaeal strains that belong to a new haloarchaeal genus and to obtain their genomic sequences. The phylogenomic and phylogenetic analyses (together with AAI, ANI and digital DDH indices) showed that the isolates constitute two new species, for which we propose the names Halosegnis longus sp. nov. and Halosegnis rubeus sp. nov. The genomic-based metabolic reconstructions indicated that members of this new haloarchaeal genus have photoheterotrophic aerobic lifestyle with a typical salt-in signature. 16S rRNA gene sequence reads abundance profiles and genomic recruitment analyses revealed that the Halosegnis genus has a worldwide geographical distribution, reaching high abundance (up to 8%) in habitats with intermediate salinities.
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Affiliation(s)
- Ana Durán-Viseras
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Sevilla, 41012, Spain
| | - Adrian-Ştefan Andrei
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, České Budějovice, 370 05, Czech Republic
| | - Blanca Vera-Gargallo
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Sevilla, 41012, Spain
| | - Rohit Ghai
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre of the Czech Academy of Sciences, České Budějovice, 370 05, Czech Republic
| | - Cristina Sánchez-Porro
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Sevilla, 41012, Spain
| | - Antonio Ventosa
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Sevilla, Sevilla, 41012, Spain
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9
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Syeda AH, Dimude JU, Skovgaard O, Rudolph CJ. Too Much of a Good Thing: How Ectopic DNA Replication Affects Bacterial Replication Dynamics. Front Microbiol 2020; 11:534. [PMID: 32351461 PMCID: PMC7174701 DOI: 10.3389/fmicb.2020.00534] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 03/12/2020] [Indexed: 12/15/2022] Open
Abstract
Each cell division requires the complete and accurate duplication of the entire genome. In bacteria, the duplication process of the often-circular chromosomes is initiated at a single origin per chromosome, resulting in two replication forks that traverse the chromosome in opposite directions. DNA synthesis is completed once the two forks fuse in a region diametrically opposite the origin. In some bacteria, such as Escherichia coli, the region where forks fuse forms a specialized termination area. Polar replication fork pause sites flanking this area can pause the progression of replication forks, thereby allowing forks to enter but not to leave. Transcription of all required genes has to take place simultaneously with genome duplication. As both of these genome trafficking processes share the same template, conflicts are unavoidable. In this review, we focus on recent attempts to add additional origins into various ectopic chromosomal locations of the E. coli chromosome. As ectopic origins disturb the native replichore arrangements, the problems resulting from such perturbations can give important insights into how genome trafficking processes are coordinated and the problems that arise if this coordination is disturbed. The data from these studies highlight that head-on replication–transcription conflicts are indeed highly problematic and multiple repair pathways are required to restart replication forks arrested at obstacles. In addition, the existing data also demonstrate that the replication fork trap in E. coli imposes significant constraints to genome duplication if ectopic origins are active. We describe the current models of how replication fork fusion events can cause serious problems for genome duplication, as well as models of how such problems might be alleviated both by a number of repair pathways as well as the replication fork trap system. Considering the problems associated both with head-on replication-transcription conflicts as well as head-on replication fork fusion events might provide clues of how these genome trafficking issues have contributed to shape the distinct architecture of bacterial chromosomes.
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Affiliation(s)
- Aisha H Syeda
- Department of Biology, University of York, York, United Kingdom
| | - Juachi U Dimude
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
| | - Ole Skovgaard
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - Christian J Rudolph
- Division of Biosciences, College of Health and Life Sciences, Brunel University London, Uxbridge, United Kingdom
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10
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Abstract
In all kingdoms of life, DNA is used to encode hereditary information. Propagation of the genetic material between generations requires timely and accurate duplication of DNA by semiconservative replication prior to cell division to ensure each daughter cell receives the full complement of chromosomes. DNA synthesis of daughter strands starts at discrete sites, termed replication origins, and proceeds in a bidirectional manner until all genomic DNA is replicated. Despite the fundamental nature of these events, organisms have evolved surprisingly divergent strategies that control replication onset. Here, we discuss commonalities and differences in replication origin organization and recognition in the three domains of life.
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Affiliation(s)
- Babatunde Ekundayo
- Quantitative Biology, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Franziska Bleichert
- Quantitative Biology, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- * E-mail:
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11
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Sakai HD, Kurosawa N. Complete genome sequence of the Sulfodiicoccus acidiphilus strain HS-1 T, the first crenarchaeon that lacks polB3, isolated from an acidic hot spring in Ohwaku-dani, Hakone, Japan. BMC Res Notes 2019; 12:444. [PMID: 31331368 PMCID: PMC6647314 DOI: 10.1186/s13104-019-4488-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 07/17/2019] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Sulfodiicoccus acidiphilus HS-1T is the type species of the genus Sulfodiicoccus, a thermoacidophilic archaeon belonging to the order Sulfolobales (class Thermoprotei; phylum Crenarchaeota). While S. acidiphilus HS-1T shares many common physiological and phenotypic features with other Sulfolobales species, the similarities in their 16S rRNA gene sequences are less than 89%. In order to know the genomic features of S. acidiphilus HS-1T in the order Sulfolobales, we determined and characterized the genome of this strain. RESULTS The circular genome of S. acidiphilus HS-1T is comprised of 2353,189 bp with a G+C content of 51.15 mol%. A total of 2459 genes were predicted, including 2411 protein coding and 48 RNA genes. The notable genomic features of S. acidiphilus HS-1T in Sulfolobales species are the absence of genes for polB3 and the autotrophic carbon fixation pathway, and the distribution pattern of essential genes and sequences related to genomic replication initiation. These insights contribute to an understanding of archaeal genomic diversity and evolution.
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Affiliation(s)
- Hiroyuki D Sakai
- Department of Science and Engineering for Sustainable Innovation, Faculty of Science and Engineering, Soka University, 1-236 Tangi-machi, Hachioji, Tokyo, 192-8577, Japan.,Japan Society for the Promotion of Science, Chiyoda-ku, Tokyo, 102-8471, Japan
| | - Norio Kurosawa
- Department of Science and Engineering for Sustainable Innovation, Faculty of Science and Engineering, Soka University, 1-236 Tangi-machi, Hachioji, Tokyo, 192-8577, Japan.
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12
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Influence of Origin Recognition Complex Proteins on the Copy Numbers of Three Chromosomes in Haloferax volcanii. J Bacteriol 2018; 200:JB.00161-18. [PMID: 29941422 DOI: 10.1128/jb.00161-18] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/17/2018] [Indexed: 12/22/2022] Open
Abstract
Replication initiation in archaea involves a protein named ORC, Cdc6, or ORC1/Cdc6, which is homologous to the eukaryotic origin recognition complex (ORC) proteins and to the eukaryotic Cdc6. Archaeal replication origins are comprised of origin repeat regions and adjacent orc genes. Some archaea contain a single replication origin and a single orc gene, while others have more than one of each. Haloferax volcanii is exceptional because it contains, in total, six replication origins on three chromosomes and 16 orc genes. Phylogenetic trees were constructed that showed that orc gene duplications occurred at very different times in evolution. To unravel the influence of the ORC proteins on chromosome copy number and cellular fitness, it was attempted to generate deletion mutants of all 16 genes. A total of 12 single-gene deletion mutants could be generated, and only three orc gene turned out to be essential. For one gene, the deletion analysis failed. Growth analyses revealed that no deletion mutant had a growth defect, but some had a slight growth advantage compared to the wild type. Quantification of the chromosome copy numbers in the deletion mutants showed that all 12 ORC proteins influenced the copy numbers of one, two, or all three chromosomes. The lack of an ORC led to an increase or decrease of chromosome copy number. Therefore, chromosome copy numbers in Hfxvolcanii are regulated by an intricate network of ORC proteins. This is in contrast to other archaea, in which ORC proteins typically bind specifically to the adjacent origin.IMPORTANCE The core origins of archaea are comprised of a repeat region and an adjacent gene for an origin recognition complex (ORC) protein, which is homologous to eukaryotic ORC proteins. Haloferax volcanii is exceptional because it contains six replication origins on three chromosomes and an additional 10 orc genes that are not adjacent to an origin. This unique ORC protein repertoire was used to unravel the importance of core origin orc genes and of origin-remote orc genes. Remarkably, all ORC proteins influenced the copy number of at least one chromosome. Some of them influenced those of all three chromosomes, showing that cross-regulation in trans exists in Hfx. volcanii Furthermore, the evolution of the archaeal ORC protein family was analyzed.
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13
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Goodman DA, Stedman KM. Comparative genetic and genomic analysis of the novel fusellovirus Sulfolobus spindle-shaped virus 10. Virus Evol 2018; 4:vey022. [PMID: 30094064 PMCID: PMC6080066 DOI: 10.1093/ve/vey022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Viruses that infect thermophilic Archaea are unique in both their structure and genetic makeup. The lemon-shaped fuselloviruses—which infect members of the order Sulfolobales, growing optimally at 80 °C and pH 3—are some of the most ubiquitous and best studied viruses of the thermoacidophilic Archaea. Nonetheless, much remains to be learned about these viruses. In order to investigate fusellovirus evolution, we have isolated and characterized a novel fusellovirus, Sulfolobus spindle-shaped virus 10 (formerly SSV-L1). Comparative genomic analyses highlight significant similarity with both SSV8 and SSV9, as well as conservation of promoter elements within the Fuselloviridae. SSV10 encodes five ORFs with no homology within or outside of the Fuselloviridae, as well as a putatively functional Cas4-like ORF, which may play a role in evading CRISPR-mediated host defenses. Moreover, we demonstrate the ability of SSV10 to withstand mutation in a fashion consistent with mutagenesis in SSV1.
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Affiliation(s)
- David A Goodman
- Biology Department, Center for Life in Extreme Environments, Portland State University, Portland, OR, USA
| | - Kenneth M Stedman
- Biology Department, Center for Life in Extreme Environments, Portland State University, Portland, OR, USA
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Luo H, Quan CL, Peng C, Gao F. Recent development of Ori-Finder system and DoriC database for microbial replication origins. Brief Bioinform 2018; 20:1114-1124. [DOI: 10.1093/bib/bbx174] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 12/04/2017] [Indexed: 01/28/2023] Open
Abstract
Abstract
DNA replication begins at replication origins in all three domains of life. Identification and characterization of replication origins are important not only in providing insights into the structure and function of the replication origins but also in understanding the regulatory mechanisms of the initiation step in DNA replication. The Z-curve method has been used in the identification of replication origins in archaeal genomes successfully since 2002. Furthermore, the Web servers of Ori-Finder and Ori-Finder 2 have been developed to predict replication origins in both bacterial and archaeal genomes based on the Z-curve method, and the replication origins with manual curation have been collected into an online database, DoriC. Ori-Finder system and DoriC database are currently used in the research field of DNA replication origins in prokaryotes, including: (i) identification of oriC regions in bacterial and archaeal genomes; (ii) discovery and analysis of the conserved sequences within oriC regions; and (iii) strand-biased analysis of bacterial genomes.
Up to now, more and more predicted results by Ori-Finder system were supported by subsequent experiments, and Ori-Finder system has been used to identify the replication origins in > 100 newly sequenced prokaryotes in their genome reports. In addition, the data in DoriC database have been widely used in the large-scale analyses of replication origins and strand bias in prokaryotic genomes. Here, we review the development of Ori-Finder system and DoriC database as well as their applications. Some future directions and aspects for extending the application of Ori-Finder and DoriC are also presented.
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Characterization of Copy Number Control of Two Haloferax volcanii Replication Origins Using Deletion Mutants and Haloarchaeal Artificial Chromosomes. J Bacteriol 2017; 200:JB.00517-17. [PMID: 29038254 DOI: 10.1128/jb.00517-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/08/2017] [Indexed: 12/17/2022] Open
Abstract
Haloferax volcanii is polyploid and contains about 20 genome copies under optimal conditions. However, the chromosome copy number is highly regulated and ranges from two during phosphate starvation to more than 40 under conditions of phosphate surplus. The aim of this study was the characterization of the influence of two replication origins on the genome copy number. The origin repeats and the genes encoding origin recognition complex (ORC) proteins were deleted. The core origin oriC1-orc1 (ori1) deletion mutant had a lower genome copy number and a higher level of fitness than the wild type, in stark contrast to the oriC2-orc5 (ori2) deletion mutant. The genes adjacent to ori1 could not be deleted, and thus, at least two of them are probably essential, while deletion of the genes adjacent to ori2 was possible. Various fragments of and around the origins were cloned into a suicide plasmid to generate haloarchaeal artificial chromosomes (HACs). The copy number of the oriC1-orc1 HAC was much higher than that of the oriC2-orc5 HAC. The addition of adjacent genes influenced both the HAC copy number and the chromosome copy number. The results indicate that the origins of H. volcanii are not independent but that the copy number is regulated via a network of genes around the origins.IMPORTANCE Several species of archaea have more than one origin of replication on their major chromosome and are thus the only known prokaryotic species that allow the analysis of the evolution of multiorigin replication. The widely studied Haloferax volcanii H26 strain has a major chromosome with four origins of replication. Two origins, ori1 and ori2, were chosen for an in-depth analysis using deletion mutants and haloarchaeal artificial chromosomes. The analysis was not restricted to the core origin regions; origin-adjacent genes were also included. Because H. volcanii is polyploid, the effects on the chromosome copy number were of specific importance. The results revealed extreme differences between the two origins.
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16
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diCenzo GC, Finan TM. The Divided Bacterial Genome: Structure, Function, and Evolution. Microbiol Mol Biol Rev 2017; 81:e00019-17. [PMID: 28794225 PMCID: PMC5584315 DOI: 10.1128/mmbr.00019-17] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Approximately 10% of bacterial genomes are split between two or more large DNA fragments, a genome architecture referred to as a multipartite genome. This multipartite organization is found in many important organisms, including plant symbionts, such as the nitrogen-fixing rhizobia, and plant, animal, and human pathogens, including the genera Brucella, Vibrio, and Burkholderia. The availability of many complete bacterial genome sequences means that we can now examine on a broad scale the characteristics of the different types of DNA molecules in a genome. Recent work has begun to shed light on the unique properties of each class of replicon, the unique functional role of chromosomal and nonchromosomal DNA molecules, and how the exploitation of novel niches may have driven the evolution of the multipartite genome. The aims of this review are to (i) outline the literature regarding bacterial genomes that are divided into multiple fragments, (ii) provide a meta-analysis of completed bacterial genomes from 1,708 species as a way of reviewing the abundant information present in these genome sequences, and (iii) provide an encompassing model to explain the evolution and function of the multipartite genome structure. This review covers, among other topics, salient genome terminology; mechanisms of multipartite genome formation; the phylogenetic distribution of multipartite genomes; how each part of a genome differs with respect to genomic signatures, genetic variability, and gene functional annotation; how each DNA molecule may interact; as well as the costs and benefits of this genome structure.
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Affiliation(s)
- George C diCenzo
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Turlough M Finan
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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17
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Construction of Expression Shuttle Vectors for the Haloarchaeon Natrinema sp. J7 Based on Its Chromosomal Origins of Replication. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2017; 2017:4237079. [PMID: 28348508 PMCID: PMC5350488 DOI: 10.1155/2017/4237079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 11/28/2016] [Accepted: 12/26/2016] [Indexed: 12/11/2022]
Abstract
Haloarchaeon Natrinema sp. J7, the first reported archaeon harboring both plasmid and chromosome-based temperate viruses, is a useful model for investigating archaeal virus-host and virus-virus interactions. However, the lack of genetic tools has limited such studies. On the basis of the automatically replicating sequences of the J7 chromosome and the pyrF marker, we constructed seven vectors, six of which were confirmed to possess replication ability in a pyrF-deletion derivative of J7 (J7-F). Among these vectors, pFJ1, pFJ4, and pFJ6 could be transformed into the host strain with relatively high efficiency (approximately 103 colony-forming units/μg DNA) and were present at about one copy per chromosome. These three vectors could be stably maintained in J7-F without selection and were used for heterologous protein expression. Only pFJ6 was found to be present in the transformed cells in an exclusively episomal, nonintegrated state (one copy per chromosome). In contrast, some pFJ1 and pFJ4 DNA was probably integrated into the J7-F chromosome. In addition, pFJ6 was found to be compatible with pYCJ in J7 cells, suggesting that these two vectors could be used for further studies of virus-virus and virus-host interactions.
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18
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Ausiannikava D, Allers T. Diversity of DNA Replication in the Archaea. Genes (Basel) 2017; 8:genes8020056. [PMID: 28146124 PMCID: PMC5333045 DOI: 10.3390/genes8020056] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/20/2017] [Indexed: 02/07/2023] Open
Abstract
DNA replication is arguably the most fundamental biological process. On account of their shared evolutionary ancestry, the replication machinery found in archaea is similar to that found in eukaryotes. DNA replication is initiated at origins and is highly conserved in eukaryotes, but our limited understanding of archaea has uncovered a wide diversity of replication initiation mechanisms. Archaeal origins are sequence-based, as in bacteria, but are bound by initiator proteins that share homology with the eukaryotic origin recognition complex subunit Orc1 and helicase loader Cdc6). Unlike bacteria, archaea may have multiple origins per chromosome and multiple Orc1/Cdc6 initiator proteins. There is no consensus on how these archaeal origins are recognised—some are bound by a single Orc1/Cdc6 protein while others require a multi- Orc1/Cdc6 complex. Many archaeal genomes consist of multiple parts—the main chromosome plus several megaplasmids—and in polyploid species these parts are present in multiple copies. This poses a challenge to the regulation of DNA replication. However, one archaeal species (Haloferax volcanii) can survive without replication origins; instead, it uses homologous recombination as an alternative mechanism of initiation. This diversity in DNA replication initiation is all the more remarkable for having been discovered in only three groups of archaea where in vivo studies are possible.
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Affiliation(s)
- Darya Ausiannikava
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK;.
| | - Thorsten Allers
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK;.
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19
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Parker MW, Botchan MR, Berger JM. Mechanisms and regulation of DNA replication initiation in eukaryotes. Crit Rev Biochem Mol Biol 2017; 52:107-144. [PMID: 28094588 DOI: 10.1080/10409238.2016.1274717] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cellular DNA replication is initiated through the action of multiprotein complexes that recognize replication start sites in the chromosome (termed origins) and facilitate duplex DNA melting within these regions. In a typical cell cycle, initiation occurs only once per origin and each round of replication is tightly coupled to cell division. To avoid aberrant origin firing and re-replication, eukaryotes tightly regulate two events in the initiation process: loading of the replicative helicase, MCM2-7, onto chromatin by the origin recognition complex (ORC), and subsequent activation of the helicase by its incorporation into a complex known as the CMG. Recent work has begun to reveal the details of an orchestrated and sequential exchange of initiation factors on DNA that give rise to a replication-competent complex, the replisome. Here, we review the molecular mechanisms that underpin eukaryotic DNA replication initiation - from selecting replication start sites to replicative helicase loading and activation - and describe how these events are often distinctly regulated across different eukaryotic model organisms.
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Affiliation(s)
- Matthew W Parker
- a Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD , USA
| | - Michael R Botchan
- b Department of Molecular and Cell Biology , University of California Berkeley , Berkeley , CA , USA
| | - James M Berger
- a Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD , USA
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20
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Barillà D. Driving Apart and Segregating Genomes in Archaea. Trends Microbiol 2016; 24:957-967. [PMID: 27450111 PMCID: PMC5120986 DOI: 10.1016/j.tim.2016.07.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/16/2016] [Accepted: 07/01/2016] [Indexed: 11/01/2022]
Abstract
Genome segregation is a fundamental biological process in organisms from all domains of life. How this stage of the cell cycle unfolds in Eukarya has been clearly defined and considerable progress has been made to unravel chromosome partition in Bacteria. The picture is still elusive in Archaea. The lineages of this domain exhibit different cell-cycle lifestyles and wide-ranging chromosome copy numbers, fluctuating from 1 up to 55. This plurality of patterns suggests that a variety of mechanisms might underpin disentangling and delivery of DNA molecules to daughter cells. Here I describe recent developments in archaeal genome maintenance, including investigations of novel genome segregation machines that point to unforeseen bacterial and eukaryotic connections.
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Affiliation(s)
- Daniela Barillà
- Department of Biology, University of York, York YO10 5DD, UK.
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21
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Manzella MP, Holmes DE, Rocheleau JM, Chung A, Reguera G, Kashefi K. The complete genome sequence and emendation of the hyperthermophilic, obligate iron-reducing archaeon "Geoglobus ahangari" strain 234(T). Stand Genomic Sci 2015; 10:77. [PMID: 26457129 PMCID: PMC4600277 DOI: 10.1186/s40793-015-0035-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/07/2015] [Indexed: 11/10/2022] Open
Abstract
“Geoglobus ahangari” strain 234T is an obligate Fe(III)-reducing member of the Archaeoglobales, within the archaeal phylum Euryarchaeota, isolated from the Guaymas Basin hydrothermal system. It grows optimally at 88 °C by coupling the reduction of Fe(III) oxides to the oxidation of a wide range of compounds, including long-chain fatty acids, and also grows autotrophically with hydrogen and Fe(III). It is the first archaeon reported to use a direct contact mechanism for Fe(III) oxide reduction, relying on a single archaellum for locomotion, numerous curled extracellular appendages for attachment, and outer-surface heme-containing proteins for electron transfer to the insoluble Fe(III) oxides. Here we describe the annotation of the genome of “G. ahangari” strain 234T and identify components critical to its versatility in electron donor utilization and obligate Fe(III) respiratory metabolism at high temperatures. The genome comprises a single, circular chromosome of 1,770,093 base pairs containing 2034 protein-coding genes and 52 RNA genes. In addition, emended descriptions of the genus “Geoglobus” and species “G. ahangari” are described.
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Affiliation(s)
- Michael P Manzella
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI USA
| | - Dawn E Holmes
- Department of Physical and Biological Sciences, Western New England University, Springfield, MA USA
| | - Jessica M Rocheleau
- Department of Physical and Biological Sciences, Western New England University, Springfield, MA USA
| | - Amanda Chung
- Department of Physical and Biological Sciences, Western New England University, Springfield, MA USA
| | - Gemma Reguera
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI USA
| | - Kazem Kashefi
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI USA
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22
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Activation of a dormant replication origin is essential for Haloferax mediterranei lacking the primary origins. Nat Commun 2015; 6:8321. [PMID: 26374389 PMCID: PMC4595724 DOI: 10.1038/ncomms9321] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 08/11/2015] [Indexed: 01/21/2023] Open
Abstract
The use of multiple origins for chromosome replication has been demonstrated in archaea. Similar to the dormant origins in eukaryotes, some potential origins in archaea appear to be inactive during genome replication. We have comprehensively explored the origin utilization in Haloferax mediterranei. Here we report three active chromosomal origins by genome-wide replication profiling, and demonstrate that when these three origins are deleted, a dormant origin becomes activated. Notably, this dormant origin cannot be further deleted when the other origins are already absent and vice versa. Interestingly, a potential origin that appears to stay dormant in its native host H. volcanii lacking the main active origins becomes activated and competent for replication of the entire chromosome when integrated into the chromosome of origin-deleted H. mediterranei. These results indicate that origin-dependent replication is strictly required for H. mediterranei and that dormant replication origins in archaea can be activated if needed.
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23
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Luo H, Zhang CT, Gao F. Ori-Finder 2, an integrated tool to predict replication origins in the archaeal genomes. Front Microbiol 2014; 5:482. [PMID: 25309521 PMCID: PMC4164010 DOI: 10.3389/fmicb.2014.00482] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 08/27/2014] [Indexed: 11/13/2022] Open
Abstract
DNA replication is one of the most basic processes in all three domains of cellular life. With the advent of the post-genomic era, the increasing number of complete archaeal genomes has created an opportunity for exploration of the molecular mechanisms for initiating cellular DNA replication by in vivo experiments as well as in silico analysis. However, the location of replication origins (oriCs) in many sequenced archaeal genomes remains unknown. We present a web-based tool Ori-Finder 2 to predict oriCs in the archaeal genomes automatically, based on the integrated method comprising the analysis of base composition asymmetry using the Z-curve method, the distribution of origin recognition boxes identified by FIMO tool, and the occurrence of genes frequently close to oriCs. The web server is also able to analyze the unannotated genome sequences by integrating with gene prediction pipelines and BLAST software for gene identification and function annotation. The result of the predicted oriCs is displayed as an HTML table, which offers an intuitive way to browse the result in graphical and tabular form. The software presented here is accurate for the genomes with single oriC, but it does not necessarily find all the origins of replication for the genomes with multiple oriCs. Ori-Finder 2 aims to become a useful platform for the identification and analysis of oriCs in the archaeal genomes, which would provide insight into the replication mechanisms in archaea. The web server is freely available at http://tubic.tju.edu.cn/Ori-Finder2/.
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Affiliation(s)
- Hao Luo
- Department of Physics, Tianjin University Tianjin, China
| | | | - Feng Gao
- Department of Physics, Tianjin University Tianjin, China ; Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University Tianjin, China ; SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering Tianjin, China
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