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Gebhard LJ, Vershinin Z, Alarcón-Schumacher T, Eichler J, Erdmann S. Influence of N-Glycosylation on Virus-Host Interactions in Halorubrum lacusprofundi. Viruses 2023; 15:1469. [PMID: 37515157 PMCID: PMC10384203 DOI: 10.3390/v15071469] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
N-glycosylation is a post-translational modification of proteins that occurs across all three domains of life. In Archaea, N-glycosylation is crucial for cell stability and motility, but importantly also has significant implications for virus-host interactions. While some archaeal viruses present glycosylated proteins or interact with glycosylated host proteins, the direct influence of N-glycosylation on archaeal virus-host interactions remains to be elucidated. In this study, we generated an N-glycosylation-deficient mutant of Halorubrum lacusprofundi, a halophilic archaeon commonly used to study cold adaptation, and examined the impact of compromised N-glycosylation on the infection dynamics of two very diverse viruses. While compromised N-glycosylation had no influence on the life cycle of the head-tailed virus HRTV-DL1, we observed a significant effect on membrane-containing virus HFPV-1. Both intracellular genome numbers and extracellular virus particle numbers of HFPV-1 were increased in the mutant strain, which we attribute to instability of the surface-layer which builds the protein envelope of the cell. When testing the impact of compromised N-glycosylation on the life cycle of plasmid vesicles, specialized membrane vesicles that transfer a plasmid between host cells, we determined that plasmid vesicle stability is strongly dependent on the host glycosylation machinery. Our study thus provides important insight into the role of N-glycosylation in virus-host interactions in Archaea, while pointing to how this influence strongly differs amongst various viruses and virus-like elements.
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Affiliation(s)
- L Johanna Gebhard
- Max Planck Institute for Marine Microbiology, Archaeal Virology, 28359 Bremen, Germany
| | - Zlata Vershinin
- Department of Life Sciences, Ben-Gurion University of the Negev, Beersheva 84105, Israel
| | | | - Jerry Eichler
- Department of Life Sciences, Ben-Gurion University of the Negev, Beersheva 84105, Israel
| | - Susanne Erdmann
- Max Planck Institute for Marine Microbiology, Archaeal Virology, 28359 Bremen, Germany
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Halorubrum pleomorphic virus-6 Membrane Fusion Is Triggered by an S-Layer Component of Its Haloarchaeal Host. Viruses 2022; 14:v14020254. [PMID: 35215847 PMCID: PMC8875312 DOI: 10.3390/v14020254] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/21/2022] [Accepted: 01/21/2022] [Indexed: 01/27/2023] Open
Abstract
(1) Background: Haloarchaea comprise extremely halophilic organisms of the Archaea domain. They are single-cell organisms with distinctive membrane lipids and a protein-based cell wall or surface layer (S-layer) formed by a glycoprotein array. Pleolipoviruses, which infect haloarchaeal cells, have an envelope analogous to eukaryotic enveloped viruses. One such member, Halorubrum pleomorphic virus 6 (HRPV-6), has been shown to enter host cells through virus-cell membrane fusion. The HRPV-6 fusion activity was attributed to its VP4-like spike protein, but the physiological trigger required to induce membrane fusion remains yet unknown. (2) Methods: We used SDS-PAGE mass spectroscopy to characterize the S-layer extract, established a proteoliposome system, and used R18-fluorescence dequenching to measure membrane fusion. (3) Results: We show that the S-layer extraction by Mg2+ chelating from the HRPV-6 host, Halorubrum sp. SS7-4, abrogates HRPV-6 membrane fusion. When we in turn reconstituted the S-layer extract from Hrr. sp. SS7-4 onto liposomes in the presence of Mg2+, HRPV-6 membrane fusion with the proteoliposomes could be readily observed. This was not the case with liposomes alone or with proteoliposomes carrying the S-layer extract from other haloarchaea, such as Haloferax volcanii. (4) Conclusions: The S-layer extract from the host, Hrr. sp. SS7-4, corresponds to the physiological fusion trigger of HRPV-6.
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Abstract
In previous publications, it was hypothesized that Micrarchaeota cells are covered by two individual membrane systems. This study proves that at least the recently cultivated "Candidatus Micrarchaeum harzensis A_DKE" possesses an S-layer covering its cytoplasmic membrane. The potential S-layer protein was found to be among the proteins with the highest abundance in "Ca. Micrarchaeum harzensis A_DKE" and in silico characterisation of its primary structure indicated homologies to other known S-layer proteins. Homologues of this protein were found in other Micrarchaeota genomes, which raises the question of whether the ability to form an S-layer is a common trait within this phylum. The S-layer protein seems to be glycosylated and the Micrarchaeon expresses genes for N-glycosylation under cultivation conditions, despite not being able to synthesize carbohydrates. Electron micrographs of freeze-etched samples of a previously described co-culture, containing Micrarchaeum A_DKE and a Thermoplasmatales member as its host organism, verified the hypothesis of an S-layer on the surface of "Ca. Micrarchaeum harzensis A_DKE". Both organisms are clearly distinguishable by cell size, shape and surface structure. Importance Our knowledge about the DPANN superphylum, which comprises several archaeal phyla with limited metabolic capacities, is mostly based on genomic data derived from cultivation-independent approaches. This study examined the surface structure of a recently cultivated member "Candidatus Micrarchaeum harzensis A_DKE", an archaeal symbiont dependent on an interaction with a host organism for growth. The interaction requires direct cell contact between interaction partners, a mechanism which is also described for other DPANN archaea. Investigating the surface structure of "Ca. Micrarchaeum harzensis A_DKE" is an important step towards understanding the interaction between Micrarchaeota and their host organisms and living with limited metabolic capabilities, a trait shared by several DPANN archaea.
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Open Issues for Protein Function Assignment in Haloferax volcanii and Other Halophilic Archaea. Genes (Basel) 2021; 12:genes12070963. [PMID: 34202810 PMCID: PMC8305020 DOI: 10.3390/genes12070963] [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] [Received: 05/16/2021] [Revised: 06/10/2021] [Accepted: 06/15/2021] [Indexed: 12/14/2022] Open
Abstract
Background: Annotation ambiguities and annotation errors are a general challenge in genomics. While a reliable protein function assignment can be obtained by experimental characterization, this is expensive and time-consuming, and the number of such Gold Standard Proteins (GSP) with experimental support remains very low compared to proteins annotated by sequence homology, usually through automated pipelines. Even a GSP may give a misleading assignment when used as a reference: the homolog may be close enough to support isofunctionality, but the substrate of the GSP is absent from the species being annotated. In such cases, the enzymes cannot be isofunctional. Here, we examined a variety of such issues in halophilic archaea (class Halobacteria), with a strong focus on the model haloarchaeon Haloferax volcanii. Results: Annotated proteins of Hfx. volcanii were identified for which public databases tend to assign a function that is probably incorrect. In some cases, an alternative, probably correct, function can be predicted or inferred from the available evidence, but this has not been adopted by public databases because experimental validation is lacking. In other cases, a probably invalid specific function is predicted by homology, and while there is evidence that this assigned function is unlikely, the true function remains elusive. We listed 50 of those cases, each with detailed background information, so that a conclusion about the most likely biological function can be drawn. For reasons of brevity and comprehension, only the key aspects are listed in the main text, with detailed information being provided in a corresponding section of the Supplementary Materials. Conclusions: Compiling, describing and summarizing these open annotation issues and functional predictions will benefit the scientific community in the general effort to improve the evaluation of protein function assignments and more thoroughly detail them. By highlighting the gaps and likely annotation errors currently in the databases, we hope this study will provide a framework for experimentalists to systematically confirm (or disprove) our function predictions or to uncover yet more unexpected functions.
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Comprehensive glycoproteomics shines new light on the complexity and extent of glycosylation in archaea. PLoS Biol 2021; 19:e3001277. [PMID: 34138841 PMCID: PMC8241124 DOI: 10.1371/journal.pbio.3001277] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/29/2021] [Accepted: 05/10/2021] [Indexed: 12/19/2022] Open
Abstract
Glycosylation is one of the most complex posttranslational protein modifications. Its importance has been established not only for eukaryotes but also for a variety of prokaryotic cellular processes, such as biofilm formation, motility, and mating. However, comprehensive glycoproteomic analyses are largely missing in prokaryotes. Here, we extend the phenotypic characterization of N-glycosylation pathway mutants in Haloferax volcanii and provide a detailed glycoproteome for this model archaeon through the mass spectrometric analysis of intact glycopeptides. Using in-depth glycoproteomic datasets generated for the wild-type (WT) and mutant strains as well as a reanalysis of datasets within the Archaeal Proteome Project (ArcPP), we identify the largest archaeal glycoproteome described so far. We further show that different N-glycosylation pathways can modify the same glycosites under the same culture conditions. The extent and complexity of the Hfx. volcanii N-glycoproteome revealed here provide new insights into the roles of N-glycosylation in archaeal cell biology. A comprehensive glycoproteomic analysis of Haloferax volcanii reveals the extent and complexity of glycosylation in archaea and provides new insights into the roles of this post-translational modification in various cellular processes, including cell shape determination.
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Tittes C, Schwarzer S, Pfeiffer F, Dyall-Smith M, Rodriguez-Franco M, Oksanen HM, Quax TEF. Cellular and Genomic Properties of Haloferax gibbonsii LR2-5, the Host of Euryarchaeal Virus HFTV1. Front Microbiol 2021; 12:625599. [PMID: 33664716 PMCID: PMC7921747 DOI: 10.3389/fmicb.2021.625599] [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] [Received: 11/03/2020] [Accepted: 01/28/2021] [Indexed: 01/14/2023] Open
Abstract
Hypersaline environments are the source of many viruses infecting different species of halophilic euryarchaea. Information on infection mechanisms of archaeal viruses is scarce, due to the lack of genetically accessible virus–host models. Recently, a new archaeal siphovirus, Haloferax tailed virus 1 (HFTV1), was isolated together with its host belonging to the genus Haloferax, but it is not infectious on the widely used model euryarcheon Haloferax volcanii. To gain more insight into the biology of HFTV1 host strain LR2-5, we studied characteristics that might play a role in its virus susceptibility: growth-dependent motility, surface layer, filamentous surface structures, and cell shape. Its genome sequence showed that LR2-5 is a new strain of Haloferax gibbonsii. LR2-5 lacks obvious viral defense systems, such as CRISPR-Cas, and the composition of its cell surface is different from Hfx. volcanii, which might explain the different viral host range. This work provides first deep insights into the relationship between the host of halovirus HFTV1 and other members of the genus Haloferax. Given the close relationship to the genetically accessible Hfx. volcanii, LR2-5 has high potential as a new model for virus–host studies in euryarchaea.
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Affiliation(s)
- Colin Tittes
- Archaeal Virus-Host Interactions, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Sabine Schwarzer
- Archaeal Virus-Host Interactions, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Friedhelm Pfeiffer
- Computational Biology Group, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Mike Dyall-Smith
- Computational Biology Group, Max Planck Institute of Biochemistry, Martinsried, Germany.,Department of Veterinary Biosciences, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC, Australia
| | | | - Hanna M Oksanen
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Tessa E F Quax
- Archaeal Virus-Host Interactions, Faculty of Biology, University of Freiburg, Freiburg, Germany
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Makkay AM, Louyakis AS, Ram-Mohan N, Gophna U, Gogarten JP, Papke RT. Insights into gene expression changes under conditions that facilitate horizontal gene transfer (mating) of a model archaeon. Sci Rep 2020; 10:22297. [PMID: 33339886 PMCID: PMC7749143 DOI: 10.1038/s41598-020-79296-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/19/2020] [Indexed: 12/16/2022] Open
Abstract
Horizontal gene transfer is a means by which bacteria, archaea, and eukaryotes are able to trade DNA within and between species. While there are a variety of mechanisms through which this genetic exchange can take place, one means prevalent in the archaeon Haloferax volcanii involves the transient formation of cytoplasmic bridges between cells and is referred to as mating. This process can result in the exchange of very large fragments of DNA between the participating cells. Genes governing the process of mating, including triggers to initiate mating, mechanisms of cell fusion, and DNA exchange, have yet to be characterized. We used a transcriptomic approach to gain a more detailed knowledge of how mating might transpire. By examining the differential expression of genes expressed in cells harvested from mating conditions on a filter over time and comparing them to those expressed in a shaking culture, we were able to identify genes and pathways potentially associated with mating. These analyses provide new insights into both the mechanisms and barriers of mating in Hfx. volcanii.
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Affiliation(s)
- Andrea M Makkay
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Artemis S Louyakis
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA
| | - Nikhil Ram-Mohan
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Uri Gophna
- The Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel Aviv University, P.O. Box 39040, 6997801, Tel Aviv, Israel
| | - J Peter Gogarten
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA.,Institute for Systems Genomics, 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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Bharat TAM, von Kügelgen A, Alva V. Molecular Logic of Prokaryotic Surface Layer Structures. Trends Microbiol 2020; 29:405-415. [PMID: 33121898 PMCID: PMC8559796 DOI: 10.1016/j.tim.2020.09.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022]
Abstract
Most prokaryotic cells are encased in a surface layer (S-layer) consisting of a paracrystalline array of repeating lattice-forming proteins. S-layer proteins populate a vast and diverse sequence space, performing disparate functions in prokaryotic cells, including cellular defense, cell-shape maintenance, and regulation of import and export of materials. This article highlights recent advances in the understanding of S-layer structure and assembly, made possible by rapidly evolving structural and cell biology methods. We underscore shared assembly principles revealed by recent work and discuss a common molecular framework that may be used to understand the structural organization of S-layer proteins across bacteria and archaea. Despite enormous sequence diversity in surface (S)-layer proteins, structural diversity is much lower than previously thought. S-layer proteins have a bipartite arrangement with a lattice-forming and an anchoring segment. Novel structural biology methods are revealing the architectures of S-layers in situ. S-layer assembly across prokaryotes is tightly coupled to the cell cycle, including the cell division machinery.
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Affiliation(s)
- Tanmay A M Bharat
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; Central Oxford Structural Microscopy and Imaging Centre, University of Oxford, Oxford OX1 3RE, UK.
| | - Andriko von Kügelgen
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK; Central Oxford Structural Microscopy and Imaging Centre, University of Oxford, Oxford OX1 3RE, UK
| | - Vikram Alva
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, Tübingen 72076, Germany.
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9
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Eichler J. N-glycosylation in Archaea-New roles for an ancient posttranslational modification. Mol Microbiol 2020; 114:735-741. [PMID: 32633872 DOI: 10.1111/mmi.14569] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/27/2020] [Indexed: 12/26/2022]
Abstract
Genome analysis points to N-glycosylation as being an almost universal posttranslational modification in Archaea. Although such predictions have been confirmed in only a limited number of species, such studies are making it increasingly clear that the N-linked glycans which decorate archaeal glycoproteins present diversity in terms of both glycan composition and architecture far beyond what is seen in the other two domains of life. In addition to continuing to decipher pathways of N-glycosylation, recent efforts have revealed how Archaea exploit this variability in novel roles. As well as encouraging glycoprotein synthesis, folding and assembly into properly functioning higher ordered complexes, N-glycosylation also provides Archaea with a strategy to cope with changing environments. Archaea can, moreover, exploit the apparent species-specific nature of N-glycosylation for selectivity in mating, and hence, to maintain species boundaries, and in other events where cell-selective interactions are required. At the same time, addressing components of N-glycosylation pathways across archaeal phylogeny offers support for the concept of an archaeal origin for eukaryotes. In this MicroReview, these and other recent discoveries related to N-glycosylation in Archaea are considered.
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Affiliation(s)
- Jerry Eichler
- Department of Life Sciences, Ben-Gurion University of the Negev, Beersheva, Israel
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Zink IA, Pfeifer K, Wimmer E, Sleytr UB, Schuster B, Schleper C. CRISPR-mediated gene silencing reveals involvement of the archaeal S-layer in cell division and virus infection. Nat Commun 2019; 10:4797. [PMID: 31641111 PMCID: PMC6805947 DOI: 10.1038/s41467-019-12745-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 09/18/2019] [Indexed: 12/27/2022] Open
Abstract
The S-layer is a proteinaceous surface lattice found in the cell envelope of bacteria and archaea. In most archaea, a glycosylated S-layer constitutes the sole cell wall and there is evidence that it contributes to cell shape maintenance and stress resilience. Here we use a gene-knockdown technology based on an endogenous CRISPR type III complex to gradually silence slaB, which encodes the S-layer membrane anchor in the hyperthermophilic archaeon Sulfolobus solfataricus. Silenced cells exhibit a reduced or peeled-off S-layer lattice, cell shape alterations and decreased surface glycosylation. These cells barely propagate but increase in diameter and DNA content, indicating impaired cell division; their phenotypes can be rescued through genetic complementation. Furthermore, S-layer depleted cells are less susceptible to infection with the virus SSV1. Our study highlights the usefulness of the CRISPR type III system for gene silencing in archaea, and supports that an intact S-layer is important for cell division and virus susceptibility. The S-layer is a proteinaceous envelope often found in bacterial and archaeal cells. Here, the authors use CRISPR-based technology to silence slaB, encoding the S-layer membrane anchor, to show that an intact S-layer is important for cell division and virus susceptibility in the archaeon Sulfolobus solfataricus.
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Affiliation(s)
- Isabelle Anna Zink
- Archaea Biology and Ecogenomics Division, Althanstraße 14, University of Vienna, A-1090, Vienna, Austria
| | - Kevin Pfeifer
- Archaea Biology and Ecogenomics Division, Althanstraße 14, University of Vienna, A-1090, Vienna, Austria.,Institute for Synthetic Bioarchitectures, Muthgasse 11/II, University of Natural Resources and Life Sciences, A-1190, Vienna, Austria
| | - Erika Wimmer
- Archaea Biology and Ecogenomics Division, Althanstraße 14, University of Vienna, A-1090, Vienna, Austria
| | - Uwe B Sleytr
- Institute of Biophysics, Muthgasse 11/II, University of Natural Resources and Life Sciences, A-1190, Vienna, Austria
| | - Bernhard Schuster
- Institute for Synthetic Bioarchitectures, Muthgasse 11/II, University of Natural Resources and Life Sciences, A-1190, Vienna, Austria
| | - Christa Schleper
- Archaea Biology and Ecogenomics Division, Althanstraße 14, University of Vienna, A-1090, Vienna, Austria.
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The Patchy Distribution of Restriction⁻Modification System Genes and the Conservation of Orphan Methyltransferases in Halobacteria. Genes (Basel) 2019; 10:genes10030233. [PMID: 30893937 PMCID: PMC6471742 DOI: 10.3390/genes10030233] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/13/2019] [Accepted: 03/14/2019] [Indexed: 12/26/2022] Open
Abstract
Restriction⁻modification (RM) systems in bacteria are implicated in multiple biological roles ranging from defense against parasitic genetic elements, to selfish addiction cassettes, and barriers to gene transfer and lineage homogenization. In bacteria, DNA-methylation without cognate restriction also plays important roles in DNA replication, mismatch repair, protein expression, and in biasing DNA uptake. Little is known about archaeal RM systems and DNA methylation. To elucidate further understanding for the role of RM systems and DNA methylation in Archaea, we undertook a survey of the presence of RM system genes and related genes, including orphan DNA methylases, in the halophilic archaeal class Halobacteria. Our results reveal that some orphan DNA methyltransferase genes were highly conserved among lineages indicating an important functional constraint, whereas RM systems demonstrated patchy patterns of presence and absence. This irregular distribution is due to frequent horizontal gene transfer and gene loss, a finding suggesting that the evolution and life cycle of RM systems may be best described as that of a selfish genetic element. A putative target motif (CTAG) of one of the orphan methylases was underrepresented in all of the analyzed genomes, whereas another motif (GATC) was overrepresented in most of the haloarchaeal genomes, particularly in those that encoded the cognate orphan methylase.
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