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Wu JH, McGenity TJ, Rettberg P, Simões MF, Li WJ, Antunes A. The archaeal class Halobacteria and astrobiology: Knowledge gaps and research opportunities. Front Microbiol 2022; 13:1023625. [PMID: 36312929 PMCID: PMC9608585 DOI: 10.3389/fmicb.2022.1023625] [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: 08/20/2022] [Accepted: 09/07/2022] [Indexed: 09/19/2023] Open
Abstract
Water bodies on Mars and the icy moons of the outer solar system are now recognized as likely being associated with high levels of salt. Therefore, the study of high salinity environments and their inhabitants has become increasingly relevant for Astrobiology. Members of the archaeal class Halobacteria are the most successful microbial group living in hypersaline conditions and are recognized as key model organisms for exposure experiments. Despite this, data for the class is uneven across taxa and widely dispersed across the literature, which has made it difficult to properly assess the potential for species of Halobacteria to survive under the polyextreme conditions found beyond Earth. Here we provide an overview of published data on astrobiology-linked exposure experiments performed with members of the Halobacteria, identifying clear knowledge gaps and research opportunities.
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Affiliation(s)
- Jia-Hui Wu
- State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology (MUST), Taipa, Macau SAR, China
- China National Space Administration (CNSA), Macau Center for Space Exploration and Science, Taipa, Macau SAR, China
| | - Terry J. McGenity
- School of Life Sciences, University of Essex, Colchester, United Kingdom
| | - Petra Rettberg
- German Aerospace Center (DLR), Institute of Aerospace Medicine, Köln, Germany
| | - Marta F. Simões
- State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology (MUST), Taipa, Macau SAR, China
- China National Space Administration (CNSA), Macau Center for Space Exploration and Science, Taipa, Macau SAR, China
| | - Wen-Jun Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - André Antunes
- State Key Laboratory of Lunar and Planetary Sciences, Macau University of Science and Technology (MUST), Taipa, Macau SAR, China
- China National Space Administration (CNSA), Macau Center for Space Exploration and Science, Taipa, Macau SAR, China
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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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Cyclobutane pyrimidine dimers from UVB exposure induce a hypermetabolic state in keratinocytes via mitochondrial oxidative stress. Redox Biol 2020; 38:101808. [PMID: 33264701 PMCID: PMC7708942 DOI: 10.1016/j.redox.2020.101808] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 12/13/2022] Open
Abstract
Ultraviolet B radiation (UVB) is an environmental complete carcinogen, which induces and promotes keratinocyte carcinomas, the most common human malignancies. UVB induces the formation of cyclobutane pyrimidine dimers (CPDs). Repairing CPDs through nucleotide excision repair is slow and error-prone in placental mammals. In addition to the mutagenic and malignancy-inducing effects, UVB also elicits poorly understood complex metabolic changes in keratinocytes, possibly through CPDs. To determine the effects of CPDs, CPD-photolyase was overexpressed in keratinocytes using an N1-methyl pseudouridine-containing in vitro-transcribed mRNA. CPD-photolyase, which is normally not present in placental mammals, can efficiently and rapidly repair CPDs to block signaling pathways elicited by CPDs. Keratinocytes surviving UVB irradiation turn hypermetabolic. We show that CPD-evoked mitochondrial reactive oxygen species production, followed by the activation of several energy sensor enzymes, including sirtuins, AMPK, mTORC1, mTORC2, p53, and ATM, is responsible for the compensatory metabolic adaptations in keratinocytes surviving UVB irradiation. Compensatory metabolic changes consist of enhanced glycolytic flux, Szent-Györgyi-Krebs cycle, and terminal oxidation. Furthermore, mitochondrial fusion, mitochondrial biogenesis, and lipophagy characterize compensatory hypermetabolism in UVB-exposed keratinocytes. These properties not only support the survival of keratinocytes, but also contribute to UVB-induced differentiation of keratinocytes. Our results indicate that CPD-dependent signaling acutely maintains skin integrity by supporting cellular energy metabolism.
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DasSarma S, DasSarma P, Laye VJ, Schwieterman EW. Extremophilic models for astrobiology: haloarchaeal survival strategies and pigments for remote sensing. Extremophiles 2019; 24:31-41. [PMID: 31463573 DOI: 10.1007/s00792-019-01126-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 08/05/2019] [Indexed: 10/26/2022]
Abstract
Recent progress in extremophile biology, exploration of planetary bodies in the solar system, and the detection and characterization of extrasolar planets are leading to new insights in the field of astrobiology and possible distribution of life in the universe. Among the many extremophiles on Earth, the halophilic Archaea (Haloarchaea) are especially attractive models for astrobiology, being evolutionarily ancient and physiologically versatile, potentially surviving in a variety of planetary environments and with relevance for in situ life detection. Haloarchaea are polyextremophilic with tolerance of saturating salinity, anaerobic conditions, high levels of ultraviolet and ionizing radiation, subzero temperatures, desiccation, and toxic ions. Haloarchaea survive launches into Earth's stratosphere encountering conditions similar to those found on the surface of Mars. Studies of their unique proteins are revealing mechanisms permitting activity and function in high ionic strength, perchlorates, and subzero temperatures. Haloarchaea also produce spectacular blooms visible from space due to synthesis of red-orange isoprenoid carotenoids used for photoprotection and photorepair processes and purple retinal chromoproteins for phototrophy and phototaxis. Remote sensing using visible and infrared spectroscopy has shown that haloarchaeal pigments exhibit both a discernable peak of absorption and a reflective "green edge". Since the pigments produce remotely detectable features, they may influence the spectrum from an inhabited exoplanet imaged by a future large space-based telescope. In this review, we focus primarily on studies of two Haloarchaea, Halobacterium sp. NRC-1 and Halorubrum lacusprofundi.
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Affiliation(s)
- Shiladitya DasSarma
- Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Priya DasSarma
- Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Victoria J Laye
- Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Edward W Schwieterman
- Department of Earth and Planetary Sciences, University of California, Riverside, CA, USA
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5
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Jones DL, Baxter BK. DNA Repair and Photoprotection: Mechanisms of Overcoming Environmental Ultraviolet Radiation Exposure in Halophilic Archaea. Front Microbiol 2017; 8:1882. [PMID: 29033920 PMCID: PMC5626843 DOI: 10.3389/fmicb.2017.01882] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 09/14/2017] [Indexed: 12/31/2022] Open
Abstract
Halophilic archaea push the limits of life at several extremes. In particular, they are noted for their biochemical strategies in dealing with osmotic stress, low water activity and cycles of desiccation in their hypersaline environments. Another feature common to their habitats is intense ultraviolet (UV) radiation, which is a challenge that microorganisms must overcome. The consequences of high UV exposure include DNA lesions arising directly from bond rearrangement of adjacent bipyrimidines, or indirectly from oxidative damage, which may ultimately result in mutation and cell death. As such, these microorganisms have evolved a number of strategies to navigate the threat of DNA damage, which we differentiate into two categories: DNA repair and photoprotection. Photoprotection encompasses damage avoidance strategies that serve as a "first line of defense," and in halophilic archaea include pigmentation by carotenoids, mechanisms of oxidative damage avoidance, polyploidy, and genomic signatures that make DNA less susceptible to photodamage. Photolesions that do arise are addressed by a number of DNA repair mechanisms that halophilic archaea efficiently utilize, which include photoreactivation, nucleotide excision repair, base excision repair, and homologous recombination. This review seeks to place DNA damage, repair, and photoprotection in the context of halophilic archaea and the solar radiation of their hypersaline environments. We also provide new insight into the breadth of strategies and how they may work together to produce remarkable UV-resistance for these microorganisms.
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Affiliation(s)
| | - Bonnie K. Baxter
- Department of Biology, Great Salt Lake Institute, Westminster College, Salt Lake City, UT, United States
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Bipyrimidine Signatures as a Photoprotective Genome Strategy in G + C-rich Halophilic Archaea. Life (Basel) 2016; 6:life6030037. [PMID: 27598206 PMCID: PMC5041013 DOI: 10.3390/life6030037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 08/12/2016] [Accepted: 08/25/2016] [Indexed: 12/12/2022] Open
Abstract
Halophilic archaea experience high levels of ultraviolet (UV) light in their environments and demonstrate resistance to UV irradiation. DNA repair systems and carotenoids provide UV protection but do not account for the high resistance observed. Herein, we consider genomic signatures as an additional photoprotective strategy. The predominant forms of UV-induced DNA damage are cyclobutane pyrimidine dimers, most notoriously thymine dimers (T^Ts), which form at adjacent Ts. We tested whether the high G + C content seen in halophilic archaea serves a photoprotective function through limiting T nucleotides, and thus T^T lesions. However, this speculation overlooks the other bipyrimidine sequences, all of which capable of forming photolesions to varying degrees. Therefore, we designed a program to determine the frequencies of the four bipyrimidine pairs (5’ to 3’: TT, TC, CT, and CC) within genomes of halophilic archaea and four other randomized sample groups for comparison. The outputs for each sampled genome were weighted by the intrinsic photoreactivities of each dinucleotide pair. Statistical methods were employed to investigate intergroup differences. Our findings indicate that the UV-resistance seen in halophilic archaea can be attributed in part to a genomic strategy: high G + C content and the resulting bipyrimidine signature reduces the genomic photoreactivity.
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Stantial N, Dumpe J, Pietrosimone K, Baltazar F, Crowley DJ. Transcription-coupled repair of UV damage in the halophilic archaea. DNA Repair (Amst) 2016; 41:63-68. [DOI: 10.1016/j.dnarep.2016.03.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 02/22/2016] [Accepted: 03/21/2016] [Indexed: 12/01/2022]
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Jaakkola ST, Pfeiffer F, Ravantti JJ, Guo Q, Liu Y, Chen X, Ma H, Yang C, Oksanen HM, Bamford DH. The complete genome of a viable archaeum isolated from 123-million-year-old rock salt. Environ Microbiol 2016; 18:565-79. [DOI: 10.1111/1462-2920.13130] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 03/02/2015] [Accepted: 03/15/2015] [Indexed: 12/01/2022]
Affiliation(s)
- Salla T. Jaakkola
- Department of Biosciences; Institute of Biotechnology; University of Helsinki; Helsinki Finland
| | - Friedhelm Pfeiffer
- Department of Membrane Biochemistry; Max Planck Institute of Biochemistry; München Germany
| | - Janne J. Ravantti
- Department of Biosciences; Institute of Biotechnology; University of Helsinki; Helsinki Finland
| | - Qinggong Guo
- State Key Laboratory of Virology; College of Life Sciences; Wuhan University; Wuhan China
| | - Ying Liu
- State Key Laboratory of Virology; College of Life Sciences; Wuhan University; Wuhan China
| | - Xiangdong Chen
- State Key Laboratory of Virology; College of Life Sciences; Wuhan University; Wuhan China
| | - Hongling Ma
- State Key Laboratory of Geomechanics and Geotechnical Engineering; Institute of Rock and Soil Mechanics; The Chinese Academy of Science; Wuhan China
| | - Chunhe Yang
- State Key Laboratory of Geomechanics and Geotechnical Engineering; Institute of Rock and Soil Mechanics; The Chinese Academy of Science; Wuhan China
| | - Hanna M. Oksanen
- Department of Biosciences; Institute of Biotechnology; University of Helsinki; Helsinki Finland
| | - Dennis H. Bamford
- Department of Biosciences; Institute of Biotechnology; University of Helsinki; Helsinki Finland
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Jaakkola ST, Zerulla K, Guo Q, Liu Y, Ma H, Yang C, Bamford DH, Chen X, Soppa J, Oksanen HM. Halophilic archaea cultivated from surface sterilized middle-late eocene rock salt are polyploid. PLoS One 2014; 9:e110533. [PMID: 25338080 PMCID: PMC4206341 DOI: 10.1371/journal.pone.0110533] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 09/11/2014] [Indexed: 11/24/2022] Open
Abstract
Live bacteria and archaea have been isolated from several rock salt deposits of up to hundreds of millions of years of age from all around the world. A key factor affecting their longevity is the ability to keep their genomic DNA intact, for which efficient repair mechanisms are needed. Polyploid microbes are known to have an increased resistance towards mutations and DNA damage, and it has been suggested that microbes from deeply buried rock salt would carry several copies of their genomes. Here, cultivable halophilic microbes were isolated from a surface sterilized middle-late Eocene (38–41 million years ago) rock salt sample, drilled from the depth of 800 m at Yunying salt mine, China. Eight unique isolates were obtained, which represented two haloarchaeal genera, Halobacterium and Halolamina. We used real-time PCR to show that our isolates are polyploid, with genome copy numbers of 11–14 genomes per cell in exponential growth phase. The ploidy level was slightly downregulated in stationary growth phase, but the cells still had an average genome copy number of 6–8. The polyploidy of halophilic archaea living in ancient rock salt might be a factor explaining how these organisms are able to overcome the challenge of prolonged survival during their entombment.
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Affiliation(s)
- Salla T. Jaakkola
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Karolin Zerulla
- Institute for Molecular Biology, Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Qinggong Guo
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Ying Liu
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Hongling Ma
- Institute of Rock and Soil Mechanics, The Chinese Academy of Sciences, Wuhan, Hubei, People's Republic of China
| | - Chunhe Yang
- Institute of Rock and Soil Mechanics, The Chinese Academy of Sciences, Wuhan, Hubei, People's Republic of China
| | - Dennis H. Bamford
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Xiangdong Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei, People's Republic of China
- * E-mail: (HMO); (JS); (XC)
| | - Jörg Soppa
- Institute for Molecular Biology, Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
- * E-mail: (HMO); (JS); (XC)
| | - Hanna M. Oksanen
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Helsinki, Finland
- * E-mail: (HMO); (JS); (XC)
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Oren A, Hallsworth JE. Microbial weeds in hypersaline habitats: the enigma of the weed-likeHaloferax mediterranei. FEMS Microbiol Lett 2014; 359:134-42. [DOI: 10.1111/1574-6968.12571] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 07/30/2014] [Accepted: 08/01/2014] [Indexed: 11/29/2022] Open
Affiliation(s)
- Aharon Oren
- Department of Plant & Environmental Sciences; The Alexander Silberman Institute of Life Sciences; The Hebrew University of Jerusalem; Jerusalem Israel
| | - John E. Hallsworth
- Institute for Global Food Security; School of Biological Sciences; MBC; Queen's University Belfast; Belfast UK
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Ram Mohan N, Fullmer MS, Makkay AM, Wheeler R, Ventosa A, Naor A, Gogarten JP, Papke RT. Evidence from phylogenetic and genome fingerprinting analyses suggests rapidly changing variation in Halorubrum and Haloarcula populations. Front Microbiol 2014; 5:143. [PMID: 24782838 PMCID: PMC3988388 DOI: 10.3389/fmicb.2014.00143] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 03/19/2014] [Indexed: 01/29/2023] Open
Abstract
Halobacteria require high NaCl concentrations for growth and are the dominant inhabitants of hypersaline environments above 15% NaCl. They are well-documented to be highly recombinogenic, both in frequency and in the range of exchange partners. In this study, we examine the genetic and genomic variation of cultured, naturally co-occurring environmental populations of Halobacteria. Sequence data from multiple loci (~2500 bp) identified many closely and more distantly related strains belonging to the genera Halorubrum and Haloarcula. Genome fingerprinting using a random priming PCR amplification method to analyze these isolates revealed diverse banding patterns across each of the genera and surprisingly even for isolates that are identical at the nucleotide level for five protein coding sequenced loci. This variance in genome structure even between identical multilocus sequence analysis (MLSA) haplotypes indicates that accumulation of genomic variation is rapid: faster than the rate of third codon substitutions.
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Affiliation(s)
- Nikhil Ram Mohan
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Matthew S Fullmer
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Andrea M Makkay
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Ryan Wheeler
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Antonio Ventosa
- Department of Microbiology and Parasitology, University of Seville Seville, Spain
| | - Adit Naor
- Molecular Microbiology and Biotechnology, Tel Aviv University Tel Aviv, Israel
| | - J Peter Gogarten
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - R Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
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Fujikane R, Ishino S, Ishino Y, Forterre P. Genetic analysis of DNA repair in the hyperthermophilic archaeon, Thermococcus kodakaraensis. Genes Genet Syst 2011; 85:243-57. [PMID: 21178304 DOI: 10.1266/ggs.85.243] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Extensive biochemical and structural analyses have been performed on the putative DNA repair proteins of hyperthermophilic archaea, in contrast to the few genetic analyses of the genes encoding these proteins. Accordingly, little is known about the repair pathways used by archaeal cells at high temperature. Here, we attempted to disrupt the genes encoding the potential repair proteins in the genome of the hyperthermophilic archaeon Thermococcus kodakaraensis. We succeeded in isolating null mutants of the hjc, hef, hjm, xpb, and xpd genes, but not the radA, rad50, mre11, herA, nurA, and xpg/fen1 genes. Phenotypic analyses of the gene-disrupted strains showed that the xpb and xpd null mutants are only slightly sensitive to ultraviolet (UV) irradiation, methyl methanesulfonate (MMS) and mitomycin C (MMC), as compared with the wild-type strain. The hjm null mutant showed sensitivity specifically to mitomycin C. On the other hand, the null mutants of the hjc gene lacked increasing sensitivity to any type of DNA damage. The Hef protein is particularly important for maintaining genome homeostasis, by functioning in the repair of a wide variety of DNA damage in T. kodakaraensis cells. Deletion of the entire hef gene or of the segments encoding either its nuclease or helicase domain produced similar phenotypes. The high sensitivity of the Δhef mutants to MMC suggests that Hef performs a critical function in the repair process of DNA interstrand cross-links. These damage-sensitivity profiles suggest that the archaeal DNA repair system has processes depending on repair-related proteins different from those of eukaryotic and bacterial DNA repair systems using homologous repair proteins analyzed here.
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Affiliation(s)
- Ryosuke Fujikane
- Institut de Génétique et Microbiologie, Université Paris-Sud 11, CNRS UMR 8621, 91405 Orsay Cedex, France
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Moeller R, Reitz G, Douki T, Cadet J, Horneck G, Stan-Lotter H. UV photoreactions of the extremely haloalkaliphilic euryarchaeon Natronomonas pharaonis. FEMS Microbiol Ecol 2010; 73:271-7. [PMID: 20491923 DOI: 10.1111/j.1574-6941.2010.00893.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The objective of this study was to investigate the photobiological responses of the haloalkaliphilic euryarchaeon Natronomonas pharaonis to environmentally relevant polychromatic UV radiation, simulating either the present UV radiation climate (lambda>290 nm) or that of the early Earth (lambda>220 nm), and to monochromatic UVC radiation (lambda=254 nm) for comparison with the literature data. UV-induced bipyrimidine DNA photoproducts were determined using a sensitive and accurate HPLC tandem mass spectrometry assay, allowing to identify and quantify each type of photoproducts formed in the DNA of a UV-irradiated halophilic archaeon. The thymine cytosine (TC) pyrimidine (6-4) pyrimidone photoproduct and the TC cyclobutane pyrimidine dimer accounted for almost 80% of the total induced DNA photolesions, regardless of the wavelength range tested. These prominent formation rates of TC photoproducts correlated with the genomic frequencies of TC dinucleotides in N. pharaonis.
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Affiliation(s)
- Ralf Moeller
- Radiation Biology Department, German Aerospace Center (DLR), Institute of Aerospace Medicine, Köln, Germany.
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14
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Hartman AL, Norais C, Badger JH, Delmas S, Haldenby S, Madupu R, Robinson J, Khouri H, Ren Q, Lowe TM, Maupin-Furlow J, Pohlschroder M, Daniels C, Pfeiffer F, Allers T, Eisen JA. The complete genome sequence of Haloferax volcanii DS2, a model archaeon. PLoS One 2010; 5:e9605. [PMID: 20333302 PMCID: PMC2841640 DOI: 10.1371/journal.pone.0009605] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 02/11/2010] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Haloferax volcanii is an easily culturable moderate halophile that grows on simple defined media, is readily transformable, and has a relatively stable genome. This, in combination with its biochemical and genetic tractability, has made Hfx. volcanii a key model organism, not only for the study of halophilicity, but also for archaeal biology in general. METHODOLOGY/PRINCIPAL FINDINGS We report here the sequencing and analysis of the genome of Hfx. volcanii DS2, the type strain of this species. The genome contains a main 2.848 Mb chromosome, three smaller chromosomes pHV1, 3, 4 (85, 438, 636 kb, respectively) and the pHV2 plasmid (6.4 kb). CONCLUSIONS/SIGNIFICANCE The completed genome sequence, presented here, provides an invaluable tool for further in vivo and in vitro studies of Hfx. volcanii.
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Affiliation(s)
- Amber L. Hartman
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
- UC Davis Genome Center, University of California Davis, Davis, California, United States of America
| | - Cédric Norais
- Institut de Génétique et Microbiologie, Université Paris-Sud, Paris, France
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jonathan H. Badger
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
| | - Stéphane Delmas
- Institute of Genetics, University of Nottingham, Nottingham, United Kingdom
| | - Sam Haldenby
- Institute of Genetics, University of Nottingham, Nottingham, United Kingdom
| | - Ramana Madupu
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
| | - Jeffrey Robinson
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
| | - Hoda Khouri
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
| | - Qinghu Ren
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
| | - Todd M. Lowe
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Julie Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Mecky Pohlschroder
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Charles Daniels
- Department of Microbiology, Ohio State University, Columbus, Ohio, United States of America
| | - Friedhelm Pfeiffer
- Department of Membrane Biochemistry, Max-Planck-Institute of Biochemistry, Martinsried, Germany
| | - Thorsten Allers
- Institute of Genetics, University of Nottingham, Nottingham, United Kingdom
| | - Jonathan A. Eisen
- The Institute for Genomic Research (J. Craig Venter Institute), Rockville, Maryland, United States of America
- UC Davis Genome Center, University of California Davis, Davis, California, United States of America
- Department of Medical Microbiology and Immunology, University of California Davis, Davis, California, United States of America
- Department of Evolution and Ecology, University of California Davis, Davis, California, United States of America
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Mitchell D, Brooks B. Antibodies and DNA Photoproducts: Applications, Milestones and Reference Guide. Photochem Photobiol 2010; 86:2-17. [DOI: 10.1111/j.1751-1097.2009.00673.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Fendrihan S, Bérces A, Lammer H, Musso M, Rontó G, Polacsek TK, Holzinger A, Kolb C, Stan-Lotter H. Investigating the effects of simulated martian ultraviolet radiation on Halococcus dombrowskii and other extremely halophilic archaebacteria. ASTROBIOLOGY 2009; 9:104-12. [PMID: 19215203 PMCID: PMC3182532 DOI: 10.1089/ast.2007.0234] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The isolation of viable extremely halophilic archaea from 250-million-year-old rock salt suggests the possibility of their long-term survival under desiccation. Since halite has been found on Mars and in meteorites, haloarchaeal survival of martian surface conditions is being explored. Halococcus dombrowskii H4 DSM 14522(T) was exposed to UV doses over a wavelength range of 200-400 nm to simulate martian UV flux. Cells embedded in a thin layer of laboratory-grown halite were found to accumulate preferentially within fluid inclusions. Survival was assessed by staining with the LIVE/DEAD kit dyes, determining colony-forming units, and using growth tests. Halite-embedded cells showed no loss of viability after exposure to about 21 kJ/m(2), and they resumed growth in liquid medium with lag phases of 12 days or more after exposure up to 148 kJ/m(2). The estimated D(37) (dose of 37 % survival) for Hcc. dombrowskii was > or = 400 kJ/m(2). However, exposure of cells to UV flux while in liquid culture reduced D(37) by 2 orders of magnitude (to about 1 kJ/m(2)); similar results were obtained with Halobacterium salinarum NRC-1 and Haloarcula japonica. The absorption of incoming light of shorter wavelength by color centers resulting from defects in the halite crystal structure likely contributed to these results. Under natural conditions, haloarchaeal cells become embedded in salt upon evaporation; therefore, dispersal of potential microscopic life within small crystals, perhaps in dust, on the surface of Mars could resist damage by UV radiation.
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Affiliation(s)
- Sergiu Fendrihan
- University of Salzburg, Division of Molecular Biology, Department of Microbiology, Salzburg, Austria
| | - Attila Bérces
- Research Group for Biophysics, Hungarian Academy of Sciences, Budapest, Hungary
| | - Helmut Lammer
- Space Research Institute of the Austrian Academy of Sciences, Graz, Austria
| | - Maurizio Musso
- University of Salzburg, Division of Materials Engineering and Physics, Department of Physics and Biophysics, Salzburg, Austria
| | - György Rontó
- Research Group for Biophysics, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tatjana K. Polacsek
- University of Salzburg, Division of Molecular Biology, Department of Microbiology, Salzburg, Austria
| | - Anita Holzinger
- University of Salzburg, Division of Molecular Biology, Department of Microbiology, Salzburg, Austria
| | - Christoph Kolb
- Space Research Institute of the Austrian Academy of Sciences, Graz, Austria
- On leave from the Space Research Institute of the Austrian Academy of Sciences, Graz, Austria
| | - Helga Stan-Lotter
- University of Salzburg, Division of Molecular Biology, Department of Microbiology, Salzburg, Austria
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Boubriak I, Ng WL, DasSarma P, DasSarma S, Crowley DJ, McCready SJ. Transcriptional responses to biologically relevant doses of UV-B radiation in the model archaeon, Halobacterium sp. NRC-1. SALINE SYSTEMS 2008; 4:13. [PMID: 18759987 PMCID: PMC2556686 DOI: 10.1186/1746-1448-4-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Accepted: 08/29/2008] [Indexed: 11/25/2022]
Abstract
Background Most studies of the transcriptional response to UV radiation in living cells have used UV doses that are much higher than those encountered in the natural environment, and most focus on short-wave UV (UV-C) at 254 nm, a wavelength that never reaches the Earth's surface. We have studied the transcriptional response of the sunlight-tolerant model archaeon, Halobacterium sp. NRC-1, to low doses of mid-wave UV (UV-B) to assess its response to UV radiation that is likely to be more biologically relevant. Results Halobacterium NRC-1 cells were irradiated with UV-B at doses equivalent to 30 J/m2 and 5 J/m2 of UV-C. Transcriptional profiling showed that only 11 genes were up-regulated 1.5-fold or more by both UV-B doses. The most strongly up-regulated gene was radA1 (vng2473), the archaeal homologue of RAD51/recA recombinase. The others included arj1 (vng779) (recJ-like exonuclease), top6A (vng884) and top6B (vng885) (coding for Topoisomerase VI subunits), and nrdJ (vng1644) (which encodes a subunit of ribonucleotide reductase). We have found that four of the consistently UV-B up-regulated genes, radA1 (vng2473), vng17, top6B (vng885) and vng280, share a common 11-base pair motif in their promoter region, TTTCACTTTCA. Similar sequences were found in radA promoters in other halophilic archaea, as well as in the radA promoter of Methanospirillum hungatei. We analysed the transcriptional response of a repair-deficient ΔuvrA (vng2636) ΔuvrC (vng2381) double-deletion mutant and found common themes between it and the response in repair proficient cells. Conclusion Our results show a core set of genes is consistently up-regulated after exposure to UV-B light at low, biologically relevant doses. Eleven genes were up-regulated, in wild-type cells, after two UV-B doses (comparable to UV-C doses of 30 J/m2 and 5 J/m2), and only four genes were up-regulated by all doses of UV-B and UV-C that we have used in this work and previously. These results suggest that high doses of UV-C radiation do not necessarily provide a good model for the natural response to environmental UV. We have found an 11-base pair motif upstream of the TATA box in four of the UV-B up-regulated genes and suggest that this motif is the binding site for a transcriptional regulator involved in their response to UV damage in this model archaeon.
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Affiliation(s)
- Ivan Boubriak
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.,Institute of Cell Biology and Genetic Engineering, UAS, 148 Zabolotnogo Street, Kiev, 03143, Ukraine
| | - Wooi Loon Ng
- School of Life Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
| | - Priya DasSarma
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, 701 E. Pratt St., Suite 236, Baltimore, MD 21202, USA
| | - Shiladitya DasSarma
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, 701 E. Pratt St., Suite 236, Baltimore, MD 21202, USA.,Molecular and Structural Biology Program, Greenebaum Cancer Center, University of Maryland, Baltimore, MD 21201, USA
| | - David J Crowley
- Natural Sciences Department, Assumption College, 500 Salisbury Street, Worcester, Massachusetts 01609, USA
| | - Shirley J McCready
- School of Life Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
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Zhou P, Wen J, Oren A, Chen M, Wu M. Genomic survey of sequence features for ultraviolet tolerance in haloarchaea (family Halobacteriaceae). Genomics 2007; 90:103-9. [PMID: 17498923 DOI: 10.1016/j.ygeno.2007.03.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 03/10/2007] [Accepted: 03/27/2007] [Indexed: 11/22/2022]
Abstract
We have investigated the strategy of Halobacterium sp. NRC-1 and other members of the family Halobacteriaceae to survive ultraviolet (UV) irradiation, based on an integrated analysis of various genomic and proteomic features such as dinucleotide composition and distribution of tetranucleotides in the genome and amino acid composition of the proteins. The low dipyrimidine content may help Halobacterium reduce formation of photoproducts in its genome. The usage of residues susceptible to reactive oxygen species attack is reduced significantly in Halobacterium, which helps the organism to minimize protein damage. We then correlated the expression of the zim gene with the genomic structure to reexamine the importance of the putative mismatch repair pathway proposed previously. Our results showed that Halobacterium sp. NRC-1 and other haloarchaea (Haloarcula marismortui, Haloquadratum walsbyi) have optimized their genomic and proteomic structures to reduce damage induced by UV irradiation, often present at high levels in habitats where these organisms thrive.
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Affiliation(s)
- Peng Zhou
- Department of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
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19
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Mackwan RR, Carver GT, Drake JW, Grogan DW. An unusual pattern of spontaneous mutations recovered in the halophilic archaeon Haloferax volcanii. Genetics 2006; 176:697-702. [PMID: 17194771 PMCID: PMC1893060 DOI: 10.1534/genetics.106.069666] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Spontaneous mutations in the orotate:phosphoribosyl transferase (pyrE2) gene of the halophilic archaeon Haloferax volcanii were selected by 5-fluoroorotic acid plus uracil at a rate of approximately 2 x 10(-8)/cell division in fluctuation and null-fraction tests but approximately 6 x 10(-8)/cell division in mutation-accumulation tests. The corresponding genomic mutation rates were substantially lower than those observed for other mesophilic microbial DNA genomes on the basis of similar target genes. The mutational spectrum was dominated by indels adding or deleting multiples of 3 bp. Properties of the organism contributing to this unusual mutational pattern may include phenotypic lag caused by a high chromosomal copy number and efficient promotion of strand misalignments by short direct repeats.
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Affiliation(s)
- Reena R Mackwan
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221-0006, USA
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Crowley DJ, Boubriak I, Berquist BR, Clark M, Richard E, Sullivan L, DasSarma S, McCready S. The uvrA, uvrB and uvrC genes are required for repair of ultraviolet light induced DNA photoproducts in Halobacterium sp. NRC-1. SALINE SYSTEMS 2006; 2:11. [PMID: 16970815 PMCID: PMC1590041 DOI: 10.1186/1746-1448-2-11] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2006] [Accepted: 09/13/2006] [Indexed: 11/09/2022]
Abstract
Background Sequenced archaeal genomes contain a variety of bacterial and eukaryotic DNA repair gene homologs, but relatively little is known about how these microorganisms actually perform DNA repair. At least some archaea, including the extreme halophile Halobacterium sp. NRC-1, are able to repair ultraviolet light (UV) induced DNA damage in the absence of light-dependent photoreactivation but this 'dark' repair capacity remains largely uncharacterized. Halobacterium sp. NRC-1 possesses homologs of the bacterial uvrA, uvrB, and uvrC nucleotide excision repair genes as well as several eukaryotic repair genes and it has been thought that multiple DNA repair pathways may account for the high UV resistance and dark repair capacity of this model halophilic archaeon. We have carried out a functional analysis, measuring repair capability in uvrA, uvrB and uvrC deletion mutants. Results Deletion mutants lacking functional uvrA, uvrB or uvrC genes, including a uvrA uvrC double mutant, are hypersensitive to UV and are unable to remove cyclobutane pyrimidine dimers or 6–4 photoproducts from their DNA after irradiation with 150 J/m2 of 254 nm UV-C. The UV sensitivity of the uvr mutants is greatly attenuated following incubation under visible light, emphasizing that photoreactivation is highly efficient in this organism. Phylogenetic analysis of the Halobacterium uvr genes indicates a complex ancestry. Conclusion Our results demonstrate that homologs of the bacterial nucleotide excision repair genes uvrA, uvrB, and uvrC are required for the removal of UV damage in the absence of photoreactivating light in Halobacterium sp. NRC-1. Deletion of these genes renders cells hypersensitive to UV and abolishes their ability to remove cyclobutane pyrimidine dimers and 6–4 photoproducts in the absence of photoreactivating light. In spite of this inability to repair UV damaged DNA, uvrA, uvrB and uvrC deletion mutants are substantially less UV sensitive than excision repair mutants of E. coli or yeast. This may be due to efficient damage tolerance mechanisms such as recombinational lesion bypass, bypass DNA polymerase(s) and the existence of multiple genomes in Halobacterium. Phylogenetic analysis provides no clear evidence for lateral transfer of these genes from bacteria to archaea.
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Affiliation(s)
- David J Crowley
- Natural Sciences Department, Assumption College, 500 Salisbury Street, Worcester, Massachusetts 01609 USA
| | - Ivan Boubriak
- School of Life Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Brian R Berquist
- University of Maryland Biotechnology Institute Center of Marine Biotechnology Baltimore, Maryland 21042 USA
| | - Monika Clark
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee 37235 USA
| | - Emily Richard
- Natural Sciences Department, Assumption College, 500 Salisbury Street, Worcester, Massachusetts 01609 USA
| | - Lynn Sullivan
- Natural Sciences Department, Assumption College, 500 Salisbury Street, Worcester, Massachusetts 01609 USA
| | - Shiladitya DasSarma
- University of Maryland Biotechnology Institute Center of Marine Biotechnology Baltimore, Maryland 21042 USA
- Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland 21201 USA
| | - Shirley McCready
- School of Life Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
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21
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McCready S, Müller JA, Boubriak I, Berquist BR, Ng WL, DasSarma S. UV irradiation induces homologous recombination genes in the model archaeon, Halobacterium sp. NRC-1. SALINE SYSTEMS 2005; 1:3. [PMID: 16176594 PMCID: PMC1224876 DOI: 10.1186/1746-1448-1-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Accepted: 07/04/2005] [Indexed: 02/02/2023]
Abstract
BACKGROUND A variety of strategies for survival of UV irradiation are used by cells, ranging from repair of UV-damaged DNA, cell cycle arrest, tolerance of unrepaired UV photoproducts, and shielding from UV light. Some of these responses involve UV-inducible genes, including the SOS response in bacteria and an array of genes in eukaryotes. To address the mechanisms used in the third branch of life, we have studied the model archaeon, Halobacterium sp. strain NRC-1, which tolerates high levels of solar radiation in its natural hypersaline environment. RESULTS Cells were irradiated with 30-70 J/m(2) UV-C and an immunoassay showed that the resulting DNA damage was largely repaired within 3 hours in the dark. Under such conditions, transcriptional profiling showed the most strongly up-regulated gene was radA1, the archaeal homolog of rad51/recA, which was induced 7-fold. Additional genes involved in homologous recombination, such as arj1 (recJ-like exonuclease), dbp (eukaryote-like DNA binding protein of the superfamily I DNA and RNA helicases), and rfa3 (replication protein A complex), as well as nrdJ, encoding for cobalamin-dependent ribonucleotide reductase involved in DNA metabolism, was also significantly induced in one or more of our experimental conditions. Neither prokaryotic nor eukaryotic excision repair gene homologs were induced and there was no evidence of an SOS-like response. CONCLUSION These results show that homologous recombination plays an important role in the cellular response of Halobacterium sp. NRC-1 to UV damage. Homologous recombination may permit rescue of stalled replication forks, and/or facilitate recombinational repair. In either case, this provides a mechanism for the observed high-frequency recombination among natural populations of halophilic archaea.
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Affiliation(s)
- Shirley McCready
- School of Biological Molecular Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Jochen A Müller
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, 701 E. Pratt St., Suite 236, Baltimore, MD 21202 USA
| | - Ivan Boubriak
- School of Biological Molecular Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Brian R Berquist
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, 701 E. Pratt St., Suite 236, Baltimore, MD 21202 USA
| | - Wooi Loon Ng
- School of Biological Molecular Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Shiladitya DasSarma
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, 701 E. Pratt St., Suite 236, Baltimore, MD 21202 USA
- Molecular and Structural Biology Program, Greenebaum Cancer Center, University of Maryland, Baltimore, MD 21201, USA
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22
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Kottemann M, Kish A, Iloanusi C, Bjork S, DiRuggiero J. Physiological responses of the halophilic archaeon Halobacterium sp. strain NRC1 to desiccation and gamma irradiation. Extremophiles 2005; 9:219-27. [PMID: 15844015 DOI: 10.1007/s00792-005-0437-4] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Accepted: 01/28/2005] [Indexed: 10/25/2022]
Abstract
We report that the halophilic archaeon Halobacterium sp. strain NRC-1 is highly resistant to desiccation, high vacuum and 60Co gamma irradiation. Halobacterium sp. was able to repair extensive double strand DNA breaks (DSBs) in its genomic DNA, produced both by desiccation and by gamma irradiation, within hours of damage induction. We propose that resistance to high vacuum and 60Co gamma irradiation is a consequence of its adaptation to desiccating conditions. Gamma resistance in Halobacterium sp. was dependent on growth stage with cultures in earlier stages exhibiting higher resistance. Membrane pigments, specifically bacterioruberin, offered protection against cellular damages induced by high doses (5 kGy) of gamma irradiation. High-salt conditions were found to create a protective environment against gamma irradiation in vivo by comparing the amount of DSBs induced by ionizing radiation in the chromosomal DNA of Halobacterium sp. to that of the more radiation-sensitive Escherichia coli that grows in lower-salt conditions. No inducible response was observed after exposing Halobacterium sp. to a nonlethal dose (0.5 kGy) of gamma ray and subsequently exposing the cells to either a high dose (5 kGy) of gamma ray or desiccating conditions. We find that the hypersaline environment in which Halobacterium sp. flourishes is a fundamental factor for its resistance to desiccation, damaging radiation and high vacuum.
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Affiliation(s)
- Molly Kottemann
- Department of Cell Biology and Molecular Genetics, University of Maryland, 3221 H.J. Patterson Hall, College Park, MD 20742, USA
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23
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Baliga NS, Bjork SJ, Bonneau R, Pan M, Iloanusi C, Kottemann MCH, Hood L, DiRuggiero J. Systems level insights into the stress response to UV radiation in the halophilic archaeon Halobacterium NRC-1. Genome Res 2004; 14:1025-35. [PMID: 15140832 PMCID: PMC419780 DOI: 10.1101/gr.1993504] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report a remarkably high UV-radiation resistance in the extremely halophilic archaeon Halobacterium NRC-1 withstanding up to 110 J/m2 with no loss of viability. Gene knockout analysis in two putative photolyase-like genes (phr1 and phr2) implicated only phr2 in photoreactivation. The UV-response was further characterized by analyzing simultaneously, along with gene function and protein interactions inferred through comparative genomics approaches, mRNA changes for all 2400 genes during light and dark repair. In addition to photoreactivation, three other putative repair mechanisms were identified including d(CTAG) methylation-directed mismatch repair, four oxidative damage repair enzymes, and two proteases for eliminating damaged proteins. Moreover, a UV-induced down-regulation of many important metabolic functions was observed during light repair and seems to be a phenomenon shared by all three domains of life. The systems analysis has facilitated the assignment of putative functions to 26 of 33 key proteins in the UV response through sequence-based methods and/or similarities of their predicted three-dimensional structures to known structures in the PDB. Finally, the systems analysis has raised, through the integration of experimentally determined and computationally inferred data, many experimentally testable hypotheses that describe the metabolic and regulatory networks of Halobacterium NRC-1.
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Affiliation(s)
- Nitin S Baliga
- Institute for Systems Biology, Seattle, Washington 98103, USA.
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24
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Beggs CB. A quantitative method for evaluating the photoreactivation of ultraviolet damaged microorganisms. Photochem Photobiol Sci 2002; 1:431-7. [PMID: 12856713 DOI: 10.1039/b202801h] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The lethal effect of ultraviolet (UV) light on microorganisms is well known and many studies have been undertaken into the effects of UV induced damage. Most of this work has been experimental; by comparison relatively little theoretical work has been undertaken to analyse the kinetics of the UV inactivation process, or to develop quantitative methodologies to support the experimental work. This paper presents a new and simple model for quantifying the photolysis rate. A theoretical study is also presented in this paper which quantifies photolysis rates for E. coli O26 and E. coli O157:H7. This study uses experimental data collected by Tosa and Hirata, and reveals the photolysis rate for E. coil O26 during the UV irradiation process to be 4.69 x 10(-3) m2 J(-1). By comparison, E. coli O157:H7 is much more susceptible to UV induced damage than E. coli O26, having a photolysis constant of only 2.09 x 10(-3) m2 J(-1).
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Affiliation(s)
- Clive B Beggs
- Aerobiological Research Group, School of Civil Engineering, University of Leeds, Leeds, UK LS2 9JT.
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25
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Abstract
The first half of the 20th century has seen an enormous growth in our knowledge of DNA repair, in no small part due to the work of Dirk Bootsma, Philip Hanawalt and Bryn Bridges; those honored by this issue. For the new millennium, we have asked three general questions: (A) Do we know all possible strategies of nucleotide excision repair (NER) in all organisms? (B) How is NER integrated and regulated in cells and tissues? (C) Does DNA replication represent a new frontier in the roles of DNA repair? We make some suggestions for the kinds of answers the next generation may provide. The kingdom of archea represents an untapped field for investigation of DNA repair in organisms with extreme lifestyles. NER appears to involve a similar strategy to the other kingdoms of prokaryotes and eukaryotes, but subtle differences suggest that individual components of the system may differ. NER appears to be regulated by several major factors, especially p53 and Rb which interact with transcription coupled repair and global genomic repair, respectively. Examples can be found of major regulatory changes in repair in testicular tissue and melanoma cells. Our understanding of replication of damaged DNA has undergone a revolution in recent years, with the discovery of multiple low-fidelity DNA polymerases that facilitate replicative bypass. A secondary mechanism of replication in the absence of NER or of one or more of these polymerases involves sister chromatid exchange and recombination (hMre11/hRad50/Nbs1). The relative importance of bypass and recombination is determined by the action of p53. We hypothesise that these polymerases may be involved in resolution of complex DNA structures during completion of replication and sister chromatid resolution. With these fascinating problems to investigate, the field of DNA repair will surely not disappoint the next generation.
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Affiliation(s)
- J E Cleaver
- Department of Dermatology and UCSF Cancer Center, University of California, San Francisco, CA 94143-0808, USA.
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26
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Cleaver JE. Richard B. Setlow, a commentary on seminal contributions and scientific controversies. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2001; 38:122-131. [PMID: 11746745 DOI: 10.1002/em.1062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Richard B. Setlow inspired the field of DNA repair. His demonstration that photoproducts could be quantified within cells and their excision examined experimentally pioneered the identification of nucleotide excision repair. His early work was associated with the discovery of many founding phenomena of photobiology and DNA repair: the concept of excision repair itself, correlations between DNA repair, life span and aging, variations in repair among mammalian species, caffeine sensitization to UV damage, and the xeroderma pigmentosum (XP) repair deficiencies. We may now have mapped thoroughly the landscape of DNA repair that Dick helped open to exploration, but questions persist of how comprehensively we have explored all its canyons and mesas. Research into nontraditional species and kingdoms may yet provide unexpected surprises. The signal transduction pathways and mechanisms of DNA replication arrest in damaged mammalian cells remain a challenge. The importance of repair in vivo also provides many difficult research questions. One problem of current interest is the role of endogenous DNA damage and repair in human pathology, especially neurodegeneration exemplified by many XP patients. Cancer and neurodegeneration may represent converse responses of dividing and nondividing cells to mutagenic and lethal effects of DNA damaging agents. Cell death from endogenous oxidative DNA damage (apoptosis) may be antagonistic to malignant transformation in dividing cells but may cause neurodegeneration in nondividing neural tissue. Small reductions in the efficiency of repair, especially transcription-coupled repair, may overemphasize carcinogenesis in mice, while minimizing neurodegeneration, as compared to human patients.
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Affiliation(s)
- J E Cleaver
- UCSF Cancer Center and Department of Dermatology, University of California, San Francisco, California 94143-0808, USA.
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27
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Raychaudhuri S, Karmakar P, Thakur AR. γ -Ray-Induced DNA Damage and Repair in Methanosarcina barkeri. Anaerobe 2000. [DOI: 10.1006/anae.2000.0359] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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28
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Martin EL, Reinhardt RL, Baum LL, Becker MR, Shaffer JJ, Kokjohn TA. The effects of ultraviolet radiation on the moderate halophileHalomonas elongataand the extreme halophileHalobacterium salinarum. Can J Microbiol 2000. [DOI: 10.1139/w99-122] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Both the moderately halophilic bacterium, Halomonas elongata, and the extremely halophilic archaea, Halobacterium salinarum, can be found in hypersaline environments (e.g., salterns). On complex media, H. elongata grows over a salt range of 0.05-5.2 M, whereas, H. salinarum multiplies over a salt range of 2.5-5.2 M. The purpose of this study was to illustrate the effect that solar (UV-A and UV-B) and germicidal radiation (UV-C) had on the growth patterns of these bacteria at varied salt concentrations. Halomonas elongata grown on a complex medium at 0.05, 1.37, and 4.3 M NaC1 was found to be more sensitive to UV-A and UV-B radiation, as the salt concentration of the medium increased. Halobacterium salinarum grown on a complex medium at 3.0 and 4.3 M NaC1 did not show a significant drop in viability after 39.3 kJ·m-2of UV-A and UV-B exposure. When exposed to UV-C, H. elongata exhibited substantially more sensitivity than H. salinarum. In H. elongata, differential sensitivity to UV-C was observed. At 0.05 M NaCl, H. elongata was less sensitive to UV-C than at 1.37 and 4.3 M NaCl. Both bacteria showed some photoreactivation when incubated under visible light following both UV-A, UV-B, and UV-C exposure. Mutagenesis following UV-C exposure was demonstrated by both organisms.
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Abstract
The ability to recognize and repair abnormal DNA structures is common to all forms of life. Studies in a variety of species have identified an incredible diversity of DNA repair pathways. Documenting and characterizing the similarities and differences in repair between species has important value for understanding the origin and evolution of repair pathways as well as for improving our understanding of phenotypes affected by repair (e.g., mutation rates, lifespan, tumorigenesis, survival in extreme environments). Unfortunately, while repair processes have been studied in quite a few species, the ecological and evolutionary diversity of such studies has been limited. Complete genome sequences can provide potential sources of new information about repair in different species. In this paper, we present a global comparative analysis of DNA repair proteins and processes based upon the analysis of available complete genome sequences. We use a new form of analysis that combines genome sequence information and phylogenetic studies into a composite analysis we refer to as phylogenomics. We use this phylogenomic analysis to study the evolution of repair proteins and processes and to predict the repair phenotypes of those species for which we now know the complete genome sequence.
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Affiliation(s)
- J A Eisen
- Department of Biological Sciences, Stanford University, Stanford, CA 94305-5020, USA.
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30
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Cleaver JE, States JC. The DNA damage-recognition problem in human and other eukaryotic cells: the XPA damage binding protein. Biochem J 1997; 328 ( Pt 1):1-12. [PMID: 9359827 PMCID: PMC1218880 DOI: 10.1042/bj3280001] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The capacity of human and other eukaryotic cells to recognize a disparate variety of damaged sites in DNA, and selectively excise and repair them, resides in a deceptively small simple protein, a 38-42 kDa zinc-finger binding protein, XPA (xeroderma pigmentosum group A), that has no inherent catalytic properties. One key to its damage-recognition ability resides in a DNA-binding domain which combines a zinc finger and a single-strand binding region which may infiltrate small single-stranded regions caused by helix-destabilizing lesions. Another is the augmentation of its binding capacity by interactions with other single-stranded binding proteins and helicases which co-operate in the binding and are unloaded at the binding site to facilitate further unwinding of the DNA and subsequent catalysis. The properties of these reactions suggest there must be considerable conformational changes in XPA and associated proteins to provide a flexible fit to a wide variety of damaged structures in the DNA.
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Affiliation(s)
- J E Cleaver
- Laboratory of Radiobiology and Environmental Health, University of California, San Francisco 94143-0750, USA
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