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Gupta T, Chahota R. Unique ankyrin repeat proteins in the genome of poxviruses-Boon or Wane, a critical review. Gene 2024; 927:148759. [PMID: 38992761 DOI: 10.1016/j.gene.2024.148759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 06/29/2024] [Accepted: 07/08/2024] [Indexed: 07/13/2024]
Abstract
Ankyrin repeat is a 33-amino acid motif commonly observed in eukaryotes and, to a lesser extent, in prokaryotes and archaea and rarely in viruses. This motif plays a crucial role in regulating various cellular processes like the cell cycle, transcription, cell signaling, and inflammatory responses through interactions between proteins. Poxviruses exhibit a distinctive feature of containing multiple ankyrin repeat proteins within their genomes. All the genera of poxviruses possess these proteins except molluscipox virus, crocodylidpox virus, and red squirrel poxvirus. An intriguing characteristic has generated notable interest in studying the functions of these proteins within poxvirus biology. Within poxviruses, ankyrin repeat proteins exhibit a distinct configuration, featuring ankyrin repeats in the N-terminal region and a cellular F-box homolog in the C-terminal region, which enables interactions with the cellular Skp, Cullin, F-box containing ubiquitin ligase complex. Through the examination of experimental evidences and discussions from current literature, this review elucidates the organization and role of ankyrin repeat proteins in poxviruses. Various research studies have highlighted the significant importance of these proteins in poxviral pathogenesis and, acting as factors that enhance virulence. Consequently, they represent viable targets for developing genetically altered viruses with decreased virulence, thus displaying potential as candidates for vaccines and antiviral therapeutic development contributing to safer and more effective strategies against poxviral infections.
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Affiliation(s)
- Tania Gupta
- Department of Veterinary Microbiology, Guru Angad Dev Veterinary and Animal Science University, Ludhiana, Punjab, 141012 India; Department of Veterinary Microbiology, DGCN College of Veterinary and Animal Sciences, CSK Himachal Pradesh Agricultural University, Palampur, 176062 India
| | - Rajesh Chahota
- Department of Veterinary Microbiology, DGCN College of Veterinary and Animal Sciences, CSK Himachal Pradesh Agricultural University, Palampur, 176062 India.
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Desingu PA, Rubeni TP, Nagarajan K, Sundaresan NR. Molecular evolution of 2022 multi-country outbreak-causing monkeypox virus Clade IIb. iScience 2024; 27:108601. [PMID: 38188513 PMCID: PMC10770499 DOI: 10.1016/j.isci.2023.108601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 09/16/2023] [Accepted: 11/28/2023] [Indexed: 01/09/2024] Open
Abstract
The monkeypox virus (Mpoxv) Clade IIb viruses that caused an outbreak in 2017-18 in Nigeria and its genetically related viruses have been detected in many countries and caused multi-country outbreak in 2022. Since the pandemic-causing Mpoxv Clade IIb viruses are closely related to Clade IIa viruses which mostly cause endemic, the Clade IIb Mpoxv might have certain specific genetic variations that are still largely unknown. Here, we have systematically analyzed genetic alterations in different clades of Mpox viruses. The results suggest that the Mpoxv Clade IIb have genetic variations in terms of genomic gaps, frameshift mutations, in-frame nonsense mutations, amino acid tandem repeats, and APOBEC3 mutations. Further, we observed specific genetic variations in the multiple genes specific for Clade I and Clade IIb, and exclusive genetic variations for Clade IIa and Clade IIb. Collectively, findings shed light on the evolution and genetic variations in the outbreak of 2022 causing Mpoxv Clade IIb.
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Affiliation(s)
- Perumal Arumugam Desingu
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | | | - K. Nagarajan
- Department of Veterinary Pathology, Madras Veterinary College, Vepery, Chennai 600007, Tamil Nadu
- Veterinary and Animal Sciences University (TANUVAS)
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3
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Dan Y, Yang L, Zhang H, Ren Y, He H, Yang F, Zhu J, Xiang H. The orf virus 129 protein can inhibit immune responses by interacting with host complement C1q binding protein in goat turbinate bone cells. Vet Microbiol 2023; 283:109782. [PMID: 37270925 DOI: 10.1016/j.vetmic.2023.109782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 05/19/2023] [Accepted: 05/22/2023] [Indexed: 06/06/2023]
Abstract
OBJECTIVE Contagious ecthyma is a severe and highly contagious disease caused by an orf virus (ORFV). The virus is responsible for substantial economic losses in the goat industry and threatens humans. We previously determined the role of ORFV129 protein, one of the five ankyrin-repeat proteins coded by the orf genome, in suppressing the transcription of pro-inflammatory cytokines IL-6, IL-1β and IFN-γ. In the present study, we identified 14 cellular proteins (complement C1q binding protein [C1QBP], MCM7, EIF5A, PKM, SLC6A, TSPAN6, ATP6AP2, GPS1, MMADHC, HSPB6, SLC35B1, MTF1, P3H4, and IL15RA) that interact with ORFV129 using a yeast two-hybrid system in goat turbinate bone cells (GFTCs). The interaction between ORFV129 and (C1QBP), an immune-related protein, was confirmed using immunofluorescence co-localization and co-immunoprecipitation assays. C1QBP overexpression inhibited ORFV replication, whereas the knockdown of C1QBP promoted ORFV replication in GFTCs. Furthermore, ORFV or ORFV129 increased C1QBP expression in GFTCs, indicated that ORFV129-C1QBP interaction might contribute to the ORFV-induced host immune process. In addition, our research showed that ORFV increased the expression of ORFV129, cytokine IL-6, IL-1β and IFN-γ. C1QBP overexpression induced IFN-γ production and reduced IL-6 and IL-1β production. Conversely, C1QBP knockdown induced IL-1β production and reduced IFN-γ and IL-1β production. Moreover, augmentation of ORFV129 expression enhanced the inhibition of the secretion of cytokines IL-6, IL-1β, and IFN-γ induced by the altered expression of C1QBP. These findings suggest different downstream pathways might be involved in regulating different cytokines induced by ORFV129 expression in GFTCs.
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Affiliation(s)
- Yixin Dan
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Lu Yang
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Huanrong Zhang
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Yupeng Ren
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Honghong He
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Falong Yang
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China
| | - Jiangjiang Zhu
- Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization Key Laboratory of Sichuan Province, Chengdu, China.
| | - Hua Xiang
- College of Animal & Veterinary Sciences, Southwest Minzu University, Chengdu, China.
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Poxviral ANKR/F-box Proteins: Substrate Adapters for Ubiquitylation and More. Pathogens 2022; 11:pathogens11080875. [PMID: 36014996 PMCID: PMC9414399 DOI: 10.3390/pathogens11080875] [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: 06/25/2022] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 02/01/2023] Open
Abstract
Poxviruses are double-stranded DNA viruses that infect insects and a variety of vertebrate species. The large genomes of poxviruses contain numerous genes that allow these viruses to successfully establish infection, including those that help evade the host immune response and prevent cell death. Ankyrin-repeat (ANKR)/F-box proteins are almost exclusively found in poxviruses, and they function as substrate adapters for Skp1-Cullin-1-F-box protein (SCF) multi-subunit E3 ubiquitin (Ub)-ligases. In this regard, they use their C-terminal F-box domain to bind Skp1, Cullin-1, and Roc1 to recruit cellular E2 enzymes to facilitate the ubiquitylation, and subsequent proteasomal degradation, of proteins bound to their N-terminal ANKRs. However, these proteins do not just function as substrate adapters as they also have Ub-independent activities. In this review, we examine both Ub-dependent and -independent activities of ANKR/F-box proteins and discuss how poxviruses use these proteins to counteract the host innate immune response, uncoat their genome, replicate, block cell death, and influence transcription. Finally, we consider important outstanding questions that need to be answered in order to better understand the function of this versatile protein family.
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Functional Characterization of Non-Ankyrin Repeat Domains of Orientia tsutsugamushi Ank Effectors Reveals Their Importance for Molecular Pathogenesis. Infect Immun 2022; 90:e0062821. [PMID: 35435726 DOI: 10.1128/iai.00628-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Orientia tsutsugamushi is a genetically intractable obligate intracellular bacterium, causes scrub typhus, and has one of the largest known armamentariums of ankyrin repeat-containing effectors (Anks). Most have a C-terminal F-box presumed to interact with the SCF ubiquitin ligase complex primarily based on their ability to bind overexpressed Skp1. Whether all F-box-containing Anks bind endogenous SCF components and the F-box residues essential for such interactions has gone unexplored. Many O. tsutsugamushi Ank F-boxes occur as part of a PRANC (pox protein repeats of ankyrin-C-terminal) domain. Roles of the non-F-box portion of the PRANC and intervening sequence region (ISR) that links the ankyrin repeat and F-box/PRANC domains are unknown. The functional relevance of these effectors' non-ankyrin repeat domains was investigated. The F-box was necessary for Flag-tagged versions of most F-box-containing Anks to precipitate endogenous Skp1, Cul1, and/or Rbx1, while the ISR and PRANC were dispensable. Ank toxicity in yeast was predominantly F-box dependent. Interrogations of Ank1, Ank5, and Ank6 established that L1, P2, E4, I9, and D17 of the F-box consensus are key for binding native SCF components and for Ank1 and Ank6 to inhibit NF-κB. The ISR is also essential for Ank1 and Ank6 to impair NF-κB. Ectopically expressed Ank1 and Ank6 lacking the ISR or having a mutagenized F-box incapable of binding SCF components performed as dominant-negative inhibitors to block O. tsutsugamushi NF-κB modulation. This study advances knowledge of O. tsutsugamushi Ank functional domains and offers an approach for validating their roles in infection.
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Cui H, Zhang Y, Zhang L. Progress on Poxvirus E3 Ubiquitin Ligases and Adaptor Proteins. Front Immunol 2021; 12:740223. [PMID: 34956175 PMCID: PMC8695901 DOI: 10.3389/fimmu.2021.740223] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/24/2021] [Indexed: 12/01/2022] Open
Abstract
Poxviruses have evolved a variety of innate immunity evasion mechanisms, some of which involve poxvirus-encoded E3 ubiquitin ligases and adaptor proteins. Based on their functional domains and ubiquitin transfer mechanisms, these poxvirus-encoded E3 ubiquitin ligases and adaptor proteins can be divided into five categories: PRANC, ANK/BC, BBK, P28/RING, and MARCH proteins. Although the substrates of many poxvirus E3 ubiquitin ligases remain to be discovered, most of the identified substrates are components of the innate immune system. In this review, we discuss the current research progress on poxvirus-encoded E3 ubiquitin ligases and adaptor proteins to provide mechanistic insights into the interplay between these viruses and their hosts.
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Affiliation(s)
- Haoran Cui
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Jinan, China.,Department of Pathogen Biology, School of Basic Medical Sciences, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China.,Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Yaxian Zhang
- Department of Pathogen Biology, School of Basic Medical Sciences, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China.,Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
| | - Leiliang Zhang
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital of Shandong First Medical University and Shandong Provincial Qianfoshan Hospital, Jinan, China.,Department of Pathogen Biology, School of Basic Medical Sciences, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China.,Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China
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Sun TW, Ku C. Unraveling gene content variation across eukaryotic giant viruses based on network analyses and host associations. Virus Evol 2021; 7:veab081. [PMID: 34754514 PMCID: PMC8570155 DOI: 10.1093/ve/veab081] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/31/2021] [Accepted: 09/15/2021] [Indexed: 12/31/2022] Open
Abstract
The nucleocytoplasmic large DNA viruses (NCLDVs, phylum Nucleocytoviricota) infect vertebrates, invertebrates, algae, amoebae, and other unicellular organisms across supergroups of eukaryotes and in various ecosystems. The expanding collection of their genome sequences has revolutionized our view of virus genome size and coding capacity. Phylogenetic trees based on a few core genes are commonly used as a model to understand their evolution. However, the tree topology can differ between analyses, and the vast majority of encoded genes might not share a common evolutionary history. To explore the whole-genome variation and evolution of NCLDVs, we dissected their gene contents using clustering, network, and comparative analyses. Our updated core-gene tree served as a framework to classify NCLDVs into families and intrafamilial lineages, but networks of individual genomes and family pangenomes showed patterns of gene sharing that contradict with the tree topology, in particular at higher taxonomic levels. Clustering of NCLDV genomes revealed variable granularity and degrees of gene sharing within each family, which cannot be inferred from the tree. At the level of NCLDV families, a correlation exists between gene content variation, but not core-gene sequence divergence, and host supergroup diversity. In addition, there is significantly higher gene sharing between divergent viruses that infect similar host types. The identified shared genes would be a useful resource for further functional analyses of NCLDV–host interactions. Overall this study provides a comprehensive view of gene repertoire variation in NCLDVs at different taxonomic levels, as well as a novel approach to studying the extremely diverse giant virus genomes.
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Affiliation(s)
- Tsu-Wang Sun
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Chuan Ku
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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Lant S, Maluquer de Motes C. Poxvirus Interactions with the Host Ubiquitin System. Pathogens 2021; 10:pathogens10081034. [PMID: 34451498 PMCID: PMC8399815 DOI: 10.3390/pathogens10081034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/12/2021] [Accepted: 08/13/2021] [Indexed: 12/16/2022] Open
Abstract
The ubiquitin system has emerged as a master regulator of many, if not all, cellular functions. With its large repertoire of conjugating and ligating enzymes, the ubiquitin system holds a unique mechanism to provide selectivity and specificity in manipulating protein function. As intracellular parasites viruses have evolved to modulate the cellular environment to facilitate replication and subvert antiviral responses. Poxviruses are a large family of dsDNA viruses with large coding capacity that is used to synthetise proteins and enzymes needed for replication and morphogenesis as well as suppression of host responses. This review summarises our current knowledge on how poxvirus functions rely on the cellular ubiquitin system, and how poxviruses exploit this system to their own advantage, either facilitating uncoating and genome release and replication or rewiring ubiquitin ligases to downregulate critical antiviral factors. Whilst much remains to be known about the intricate interactions established between poxviruses and the host ubiquitin system, our knowledge has revealed crucial viral processes and important restriction factors that open novel avenues for antiviral treatment and provide fundamental insights on the biology of poxviruses and other virus families.
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Orientia tsutsugamushi Nucleomodulin Ank13 Exploits the RaDAR Nuclear Import Pathway To Modulate Host Cell Transcription. mBio 2021; 12:e0181621. [PMID: 34340535 PMCID: PMC8406279 DOI: 10.1128/mbio.01816-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Orientia tsutsugamushi is the etiologic agent of scrub typhus, the deadliest of all diseases caused by obligate intracellular bacteria. Nucleomodulins, bacterial effectors that dysregulate eukaryotic transcription, are being increasingly recognized as key virulence factors. How they translocate into the nucleus and their functionally essential domains are poorly defined. We demonstrate that Ank13, an O. tsutsugamushi effector conserved among clinical isolates and expressed during infection, localizes to the nucleus in an importin β1-independent manner. Rather, Ank13 nucleotropism requires an isoleucine at the thirteenth position of its fourth ankyrin repeat, consistent with utilization of eukaryotic RaDAR (RanGDP-ankyrin repeats) nuclear import. RNA-seq analyses of cells expressing green fluorescent protein (GFP)-tagged Ank13, nucleotropism-deficient Ank13I127R, or Ank13ΔF-box, which lacks the F-box domain essential for interacting with SCF ubiquitin ligase, revealed Ank13 to be a nucleomodulin that predominantly downregulates transcription of more than 2,000 genes. Its ability to do so involves its nucleotropism and F-box in synergistic and mutually exclusive manners. Ank13 also acts in the cytoplasm to dysregulate smaller cohorts of genes. The effector’s toxicity in yeast heavily depends on its F-box and less so on its nucleotropism. Genes negatively regulated by Ank13 include those involved in the inflammatory response, transcriptional control, and epigenetics. Importantly, the majority of genes that GFP-Ank13 most strongly downregulates are quiescent or repressed in O. tsutsugamushi-infected cells when Ank13 expression is strongest. Ank13 is the first nucleomodulin identified to coopt RaDAR and a multifaceted effector that functions in the nucleus and cytoplasm via F-box-dependent and -independent mechanisms to globally reprogram host cell transcription.
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10
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Coffman KA, Burke GR. Genomic analysis reveals an exogenous viral symbiont with dual functionality in parasitoid wasps and their hosts. PLoS Pathog 2020; 16:e1009069. [PMID: 33253317 PMCID: PMC7728225 DOI: 10.1371/journal.ppat.1009069] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 12/10/2020] [Accepted: 10/15/2020] [Indexed: 02/07/2023] Open
Abstract
Insects are known to host a wide variety of beneficial microbes that are fundamental to many aspects of their biology and have substantially shaped their evolution. Notably, parasitoid wasps have repeatedly evolved beneficial associations with viruses that enable developing wasps to survive as parasites that feed from other insects. Ongoing genomic sequencing efforts have revealed that most of these virus-derived entities are fully integrated into the genomes of parasitoid wasp lineages, representing endogenous viral elements (EVEs) that retain the ability to produce virus or virus-like particles within wasp reproductive tissues. All documented parasitoid EVEs have undergone similar genomic rearrangements compared to their viral ancestors characterized by viral genes scattered across wasp genomes and specific viral gene losses. The recurrent presence of viral endogenization and genomic reorganization in beneficial virus systems identified to date suggest that these features are crucial to forming heritable alliances between parasitoid wasps and viruses. Here, our genomic characterization of a mutualistic poxvirus associated with the wasp Diachasmimorpha longicaudata, known as Diachasmimorpha longicaudata entomopoxvirus (DlEPV), has uncovered the first instance of beneficial virus evolution that does not conform to the genomic architecture shared by parasitoid EVEs with which it displays evolutionary convergence. Rather, DlEPV retains the exogenous viral genome of its poxvirus ancestor and the majority of conserved poxvirus core genes. Additional comparative analyses indicate that DlEPV is related to a fly pathogen and contains a novel gene expansion that may be adaptive to its symbiotic role. Finally, differential expression analysis during virus replication in wasps and fly hosts demonstrates a unique mechanism of functional partitioning that allows DlEPV to persist within and provide benefit to its parasitoid wasp host.
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Affiliation(s)
- Kelsey A. Coffman
- Department of Entomology, University of Georgia, Athens, Georgia, United States of America
| | - Gaelen R. Burke
- Department of Entomology, University of Georgia, Athens, Georgia, United States of America
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He C, Tong J, Zhang X, Tuohetiniyazi M, Zhang Y, Li Y. Comparative analysis of ankyrin (ANK) genes of five capripoxviruses isolate strains from Xinjiang province in China. Virol J 2020; 17:133. [PMID: 32859219 PMCID: PMC7453672 DOI: 10.1186/s12985-020-01407-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 08/19/2020] [Indexed: 11/10/2022] Open
Abstract
Background Sheeppox and goatpox are both economically important animal diseases in which pathogens are goatpox virus (GTPV) and sheeppox virus (SPPV). They can’t cause cross-species infection between sheep and goats in general. But in recent decades, the infection of sheep by goatpox or goats by sheeppox has been reported. The literature has indicated that the occurrence of these cases has a significant and direct relationship with mutations of ankyrin genes families (ANK genes 010,138,140,141.2,145) located in two-terminal regions of capripoxvirus genomes. So it is very important to decipher these nucleotides and their coding amino acid sequences of the five genes regarded as host range and virulence factors for effective prevention and control of capripoxvirus diseases. Methods In this study, all the ankyrin genes of three goatpox virus, two sheeppox virus, and one GTPV vaccine strains from Nanjiang areas of Xinjiang province of China during 2010–2011 were collected, amplified, cloned and sequenced. The sequence of every ankyrin genes has been compared with not only sequences from six viruses but also all sequences from three species of capripoxvirus genus from Gene bank, and every ANK gene’s mutated nucleotides and amino acids have been screened, and the relationship of genetic evolution among different virus strains has been analyzed, as well as the domain architecture of these genes was forecasted and analyzed. Results The six capripoxvirus strains can be well-distinguished GTPV and SPPV based on five ANK genes’ sequence identicalness except for GTPV-SS strain, which showed higher identicalness with SPPV. The ANK gene sequence of the GTPV-SS strain was 100% identical with SPPV-M1 (ANK138,140,145) and SPPV-M2 (ANK138,145), respectively. Phylogenetically, these six capripoxvirus strains were also grouped into the same cluster of India reference strains in lineages and showed extreme identical conservative or variable regions with India capripoxvirus isolates by sequence alignment. Moreover, for the functional domains, these ANK genes of capripoxvirus except for ANK gene 145, are identical in size, and ANK genes 145 of SPPV are usually 100 bp (approximately 30 aa) longer than those of GTPV and eventually form a PRANC domain at C-terminus. Conclusions The isolated strain of GTPV-SS may be a cross-species infection or the collected material was contaminated, and the inferred Capripox outbreak in Xinjiang in 2010 can be introduced from India. ANK genes 138,140,141.2 and 145 of capripoxvirus can be used as the target genes to identify GTPV and SPPV. Moreover, the four ANK genes determining the host range are more significant than the ANK gene 010. These ANK genes play combining roles for their function.
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Affiliation(s)
- Chuanchuan He
- Key Laboratory of Tarim Livestock science Technology, Alar, 843300, Xinjiang, China.,College of Animal Science in Tarim University, Alar, 843300, Xinjiang, China
| | - Jianjun Tong
- Key Laboratory of Tarim Livestock science Technology, Alar, 843300, Xinjiang, China.,College of Animal Science in Tarim University, Alar, 843300, Xinjiang, China
| | - Xueping Zhang
- Key Laboratory of Tarim Livestock science Technology, Alar, 843300, Xinjiang, China.,College of Life Science in Tarim University, Alar, 843300, Xinjiang, China
| | - Milikaimu Tuohetiniyazi
- Key Laboratory of Tarim Livestock science Technology, Alar, 843300, Xinjiang, China.,College of Animal Science in Tarim University, Alar, 843300, Xinjiang, China
| | - Yu Zhang
- College of Animal Science in Tarim University, Alar, 843300, Xinjiang, China
| | - Youwen Li
- Key Laboratory of Tarim Livestock science Technology, Alar, 843300, Xinjiang, China. .,College of Animal Science in Tarim University, Alar, 843300, Xinjiang, China. .,College of Life Science in Tarim University, Alar, 843300, Xinjiang, China.
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Biswas S, Noyce RS, Babiuk LA, Lung O, Bulach DM, Bowden TR, Boyle DB, Babiuk S, Evans DH. Extended sequencing of vaccine and wild-type capripoxvirus isolates provides insights into genes modulating virulence and host range. Transbound Emerg Dis 2019; 67:80-97. [PMID: 31379093 DOI: 10.1111/tbed.13322] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/22/2019] [Accepted: 07/30/2019] [Indexed: 11/29/2022]
Abstract
The genus Capripoxvirus in the subfamily Chordopoxvirinae, family Poxviridae, comprises sheeppox virus (SPPV), goatpox virus (GTPV) and lumpy skin disease virus (LSDV), which cause the eponymous diseases across parts of Africa, the Middle East and Asia. These diseases cause significant economic losses and can have a devastating impact on the livelihoods and food security of small farm holders. So far, only live classically attenuated SPPV, GTPV and LSDV vaccines are commercially available and the history, safety and efficacy of many have not been well established. Here, we report 13 new capripoxvirus genome sequences, including the hairpin telomeres, from both pathogenic field isolates and vaccine strains. We have also updated the genome annotations to incorporate recent advances in our understanding of poxvirus biology. These new genomes and genes grouped phenetically with other previously sequenced capripoxvirus strains, and these new alignments collectively identified several recurring alterations in genes thought to modulate virulence and host range. In particular, some of the many large capripoxvirus ankyrin and kelch-like proteins are commonly mutated in vaccine strains, while the variola virus B22R-like gene homolog has also been disrupted in many vaccine isolates. Among these vaccine isolates, frameshift mutations are especially common and clearly present a risk of reversion to wild type in vaccines bearing these mutations. A consistent pattern of gene inactivation from LSDV to GTPV and then SPPV is also observed, much like the pattern of gene loss in orthopoxviruses, but, rather surprisingly, the overall genome size of ~150 kbp remains relatively constant. These data provide new insights into the evolution of capripoxviruses and the determinants of pathogenicity and host range. They will find application in the development of new vaccines with better safety, efficacy and trade profiles.
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Affiliation(s)
- Siddhartha Biswas
- Department of Medical Microbiology and Immunology, Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB, Canada
| | - Ryan S Noyce
- Department of Medical Microbiology and Immunology, Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB, Canada
| | - Lorne A Babiuk
- Department of Agricultural, Food, and Nutritional Sciences, University of Alberta, Edmonton, AB, Canada
| | - Oliver Lung
- National Centre for Foreign Animal Disease (NCFAD), Canadian Food Inspection Agency, Winnipeg, MB, Canada
| | - Dieter M Bulach
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Vic., Australia
| | - Timothy R Bowden
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Vic., Australia
| | - David B Boyle
- CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Vic., Australia
| | - Shawn Babiuk
- National Centre for Foreign Animal Disease (NCFAD), Canadian Food Inspection Agency, Winnipeg, MB, Canada.,Department of Immunology, University of Manitoba, Winnipeg, MB, Canada
| | - David H Evans
- Department of Medical Microbiology and Immunology, Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB, Canada
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Sharif S, Ueda N, Nakatani Y, Wise LM, Clifton S, Lateef Z, Mercer AA, Fleming SB. Chemokine-Binding Proteins Encoded by Parapoxvirus of Red Deer of New Zealand Display Evidence of Gene Duplication and Divergence of Ligand Specificity. Front Microbiol 2019; 10:1421. [PMID: 31293551 PMCID: PMC6603201 DOI: 10.3389/fmicb.2019.01421] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/05/2019] [Indexed: 01/20/2023] Open
Abstract
Parapoxvirus of red deer in New Zealand (PVNZ) is a species of the Parapoxvirus genus that causes pustular dermatitis. We identified a cluster of genes in PVNZ that encode three unique chemokine-binding proteins (CBPs) namely ORF112.0, ORF112.3 and ORF112.6. Chemokines are a large family of molecules that direct cell trafficking to sites of inflammation and through lymphatic organs. The PVNZ-CBPs were analyzed by surface plasmon resonance against a broad spectrum of CXC, CC, XC and CX3C chemokines and were found to differ in their specificity and binding affinity. ORF112.0 interacted with chemokines from the CXC, CC and XC classes of chemokines with nM affinities. The ORF112.3 showed a preference for CXC chemokines, while ORF112.6 showed pM affinity binding for CC chemokines. Structural modeling analysis showed alterations in the chemokine binding sites of the CBPs, although the core structure containing two ß-sheets and three α-helices being conserved with the other parapoxvirus CBPs. Chemotaxis assays using neutrophils and monocytes revealed inhibitory impact of the CBPs on cell migration. Our results suggest that the PVNZ-CBPs are likely to have evolved through a process of gene duplication and divergence, and may have a role in suppressing inflammation and the anti-viral immune response.
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Affiliation(s)
| | | | | | | | | | | | | | - Stephen B. Fleming
- Virus Research Unit, Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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14
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Deeg CM, Zimmer MM, George EE, Husnik F, Keeling PJ, Suttle CA. Chromulinavorax destructans, a pathogen of microzooplankton that provides a window into the enigmatic candidate phylum Dependentiae. PLoS Pathog 2019; 15:e1007801. [PMID: 31150530 PMCID: PMC6561590 DOI: 10.1371/journal.ppat.1007801] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 06/12/2019] [Accepted: 04/30/2019] [Indexed: 11/25/2022] Open
Abstract
Members of the major candidate phylum Dependentiae (a.k.a. TM6) are widespread across diverse environments from showerheads to peat bogs; yet, with the exception of two isolates infecting amoebae, they are only known from metagenomic data. The limited knowledge of their biology indicates that they have a long evolutionary history of parasitism. Here, we present Chromulinavorax destructans (Strain SeV1) the first isolate of this phylum to infect a representative from a widespread and ecologically significant group of heterotrophic flagellates, the microzooplankter Spumella elongata (Strain CCAP 955/1). Chromulinavorax destructans has a reduced 1.2 Mb genome that is so specialized for infection that it shows no evidence of complete metabolic pathways, but encodes an extensive transporter system for importing nutrients and energy in the form of ATP from the host. Its replication causes extensive reorganization and expansion of the mitochondrion, effectively surrounding the pathogen, consistent with its dependency on the host for energy. Nearly half (44%) of the inferred proteins contain signal sequences for secretion, including many without recognizable similarity to proteins of known function, as well as 98 copies of proteins with an ankyrin-repeat domain; ankyrin-repeats are known effectors of host modulation, suggesting the presence of an extensive host-manipulation apparatus. These observations help to cement members of this phylum as widespread and diverse parasites infecting a broad range of eukaryotic microbes. Little is known about the biology of bacteria in the candidate phylum Dependentiae, despite being widespread in nature. Here, we describe a novel isolate of this phylum, Chromulinavorax destructans, which infects an abundant aquatic predatory protist, Spumella elongata. Chromulinavorax destructans is an obligate intracellular parasite, forgoes binary fission and replicates surrounded by the host mitochondrion. The genome of C. destructans encodes no detectable complete metabolic pathways and instead contains extensive transporter systems to import metabolites and even energy in the form of ATP from the host. We also found a surprising number of genes in the C. destructans genome encoding putative host modifying proteins that might be responsible for the extensive host reorganization. Phylogenetic analysis showed that C. destructans is distantly related to intracellular pathogens and symbionts of unrelated amoebae. Hence, Chromulinavorax destructans provides new insights into the biology of a widespread but largely unknown phylum of bacteria. These results imply that members of the Dependentiae are pathogens of diverse aquatic protists and are therefore likely important players in aquatic ecosystems.
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Affiliation(s)
- Christoph M. Deeg
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Matthias M. Zimmer
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - Emma E. George
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Filip Husnik
- Department of Botany, University of British Columbia, Vancouver, Canada
| | | | - Curtis A. Suttle
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
- Department of Botany, University of British Columbia, Vancouver, Canada
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, Canada
- * E-mail:
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15
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Halaly MA, Subramaniam K, Koda SA, Popov VL, Stone D, Way K, Waltzek TB. Characterization of a Novel Megalocytivirus Isolated from European Chub ( Squalius cephalus). Viruses 2019; 11:v11050440. [PMID: 31096590 PMCID: PMC6563503 DOI: 10.3390/v11050440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 04/26/2019] [Accepted: 04/28/2019] [Indexed: 12/29/2022] Open
Abstract
A novel virus from moribund European chub (Squalius cephalus) was isolated on epithelioma papulosum cyprini (EPC) cells. Transmission electron microscopic examination revealed abundant non-enveloped, hexagonal virus particles in the cytoplasm of infected EPC cells consistent with an iridovirus. Illumina MiSeq sequence data enabled the assembly and annotation of the full genome (128,216 bp encoding 108 open reading frames) of the suspected iridovirus. Maximum Likelihood phylogenetic analyses based on 25 iridovirus core genes supported the European chub iridovirus (ECIV) as being the sister species to the recently-discovered scale drop disease virus (SDDV), which together form the most basal megalocytivirus clade. Genetic analyses of the ECIV major capsid protein and ATPase genes revealed the greatest nucleotide identity to members of the genus Megalocytivirus including SDDV. These data support ECIV as a novel member within the genus Megalocytivirus. Experimental challenge studies are needed to fulfill River’s postulates and determine whether ECIV induces the pathognomonic microscopic lesions (i.e., megalocytes with basophilic cytoplasmic inclusions) observed in megalocytivirus infections.
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Affiliation(s)
- Maya A Halaly
- Department of Animal Sciences, College of Agricultural and Life Sciences, University of Florida, Gainesville, FL 32611, USA.
| | - Kuttichantran Subramaniam
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA.
| | - Samantha A Koda
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA.
| | - Vsevolod L Popov
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - David Stone
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Weymouth DT4 8UB, UK.
| | - Keith Way
- Centre for Environment, Fisheries and Aquaculture Science (CEFAS), Weymouth DT4 8UB, UK.
| | - Thomas B Waltzek
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, FL 32611, USA.
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16
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Novel Class of Viral Ankyrin Proteins Targeting the Host E3 Ubiquitin Ligase Cullin-2. J Virol 2018; 92:JVI.01374-18. [PMID: 30258003 PMCID: PMC6232478 DOI: 10.1128/jvi.01374-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 09/11/2018] [Indexed: 02/07/2023] Open
Abstract
Ankyrin repeat (ANK) domains are among the most abundant motifs in eukaryotic proteins. ANK proteins are rare amongst viruses, with the exception of poxviruses, which presumably acquired them from the host via horizontal gene transfer. The architecture of poxvirus ANK proteins is, however, different from that of their cellular counterparts, and this precludes a direct acquisition event. Here we combine bioinformatics analysis and quantitative proteomics to discover a new class of viral ANK proteins with a domain organization that relates to cellular ANK proteins. These noncanonical viral ANK proteins, termed ANK/BC, interact with host Cullin-2 via a C-terminal BC box resembling that of cellular Cullin-2 substrate adaptors such as the von Hippel-Lindau protein. Mutagenesis of the BC box-like sequence abrogates binding to Cullin-2, whereas fusion of this motif to an ANK-only protein confers Cullin-2 association. We demonstrated that these viral ANK/BC proteins are potent immunomodulatory proteins suppressing the activation of the proinflammatory transcription factors NF-κB and interferon (IFN)-responsive factor 3 (IRF-3) and the production of cytokines and chemokines, including interferon, and that association with Cullin-2 is required for optimal inhibitory activity. ANK/BC proteins exist in several orthopoxviruses and cluster into 2 closely related orthologue groups in a phylogenetic lineage that is separate from that of canonical ANK/F-box proteins. Given the existence of cellular proteins with similar architecture, viral ANK/BC proteins may be closely related to the original ANK gene acquired by an ancestral orthopoxvirus. These findings uncover a novel viral strategy to antagonize innate immunity and shed light on the origin of the poxviral ANK protein family.IMPORTANCE Viruses encode multiple proteins aimed at modulating cellular homeostasis and antagonizing the host antiviral response. Most of these genes were originally acquired from the host and subsequently adapted to benefit the virus. ANK proteins are common in eukaryotes but are unusual amongst viruses, with the exception of poxviruses, where they represent one of the largest protein families. We report here the existence of a new class of viral ANK proteins, termed ANK/BC, that provide new insights into the origin of poxvirus ANK proteins. ANK/BC proteins target the host E3 ubiquitin ligase Cullin-2 via a C-terminal BC box domain and are potent suppressors of the production of inflammatory cytokines, including interferon. The existence of cellular ANK proteins whose architecture is similar suggests the acquisition of a host ANK/BC gene by an ancestral orthopoxvirus and its subsequent duplication and adaptation to widen the repertoire of immune evasion strategies.
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17
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Wang R, Wang Y, Liu F, Luo S. Orf virus: A promising new therapeutic agent. Rev Med Virol 2018; 29:e2013. [PMID: 30370570 DOI: 10.1002/rmv.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/14/2018] [Accepted: 09/20/2018] [Indexed: 12/12/2022]
Abstract
The orf virus (ORFV) is a zoonotic, epitheliotropic, DNA parapoxvirus that infects principally sheep and goats. Exposure of animals to the virus or immunization by an ORFV preparation can accentuate the severity of disease, which has provoked an interest in the underlying cellular, virological, and molecular mechanisms. The identified ORFV virulence genes and the fact that the virus can repeatedly infect a host, owing to its evasive mechanisms, contribute to the development of potent immune modulators in various animal species. ORFV has been developed as a vaccine in veterinary medicine. The unique host immune-evasion ability of ORFV has made it an important candidate for vaccine vectors and biological agents (as an oncolytic virus). Genetic modifications using ORFV to obtain safe and efficient preparations and mechanistic studies are improvements to the currently available methods for disease treatment.
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Affiliation(s)
- Ruixue Wang
- Department of Laboratory Medicine, School of Stomatology and Medicine, Foshan University, Foshan, Guangdong Province, China.,Department of Basic Medical Sciences, School of Stomatology and Medicine, Foshan University, Foshan, Guangdong Province, China
| | - Yong Wang
- Department of Laboratory Medicine, School of Stomatology and Medicine, Foshan University, Foshan, Guangdong Province, China
| | - Fang Liu
- Department of Basic Medical Sciences, School of Stomatology and Medicine, Foshan University, Foshan, Guangdong Province, China
| | - Shuhong Luo
- Department of Laboratory Medicine, School of Stomatology and Medicine, Foshan University, Foshan, Guangdong Province, China
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18
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Evans SM, Rodino KG, Adcox HE, Carlyon JA. Orientia tsutsugamushi uses two Ank effectors to modulate NF-κB p65 nuclear transport and inhibit NF-κB transcriptional activation. PLoS Pathog 2018; 14:e1007023. [PMID: 29734393 PMCID: PMC5957444 DOI: 10.1371/journal.ppat.1007023] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 05/17/2018] [Accepted: 04/11/2018] [Indexed: 01/05/2023] Open
Abstract
Orientia tsutsugamushi causes scrub typhus, a potentially fatal infection that threatens over one billion people. Nuclear translocation of the transcription factor, NF-κB, is the central initiating cellular event in the antimicrobial response. Here, we report that NF-κB p65 nuclear accumulation and NF-κB-dependent transcription are inhibited in O. tsutsugamushi infected HeLa cells and/or primary macrophages, even in the presence of TNFα. The bacterium modulates p65 subcellular localization by neither degrading it nor inhibiting IκBα degradation. Rather, it exploits host exportin 1 to mediate p65 nuclear export, as this phenomenon is leptomycin B-sensitive. O. tsutsugamushi antagonizes NF-κB-activated transcription even when exportin 1 is inhibited and NF-κB consequently remains in the nucleus. Two ankyrin repeat-containing effectors (Anks), Ank1 and Ank6, each of which possess a C-terminal F-box and exhibit 58.5% amino acid identity, are linked to the pathogen's ability to modulate NF-κB. When ectopically expressed, both translocate to the nucleus, abrogate NF-κB-activated transcription in an exportin 1-independent manner, and pronouncedly reduce TNFα-induced p65 nuclear levels by exportin 1-dependent means. Flag-tagged Ank 1 and Ank6 co-immunoprecipitate p65 and exportin 1. Both also bind importin β1, a host protein that is essential for the classical nuclear import pathway. Importazole, which blocks importin β1 activity, abrogates Ank1 and Ank6 nuclear translocation. The Ank1 and Ank6 regions that bind importin β1 also mediate their transport into the nucleus. Yet, these regions are distinct from those that bind p65/exportin 1. The Ank1 and Ank6 F-box and the region that lies between it and the ankyrin repeat domain are essential for blocking p65 nuclear accumulation. These data reveal a novel mechanism by which O. tsutsugamushi modulates the activity and nuclear transport of NF-κB p65 and identify the first microbial proteins that co-opt both importin β1 and exportin 1 to antagonize a critical arm of the antimicrobial response.
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Affiliation(s)
- Sean M. Evans
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
| | - Kyle G. Rodino
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
| | - Haley E. Adcox
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
| | - Jason A. Carlyon
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, School of Medicine, Richmond, Virginia, United States of America
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19
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Sarker S, Isberg SR, Milic NL, Lock P, Helbig KJ. Molecular characterization of the first saltwater crocodilepox virus genome sequences from the world's largest living member of the Crocodylia. Sci Rep 2018; 8:5623. [PMID: 29618766 PMCID: PMC5884845 DOI: 10.1038/s41598-018-23955-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 03/20/2018] [Indexed: 12/21/2022] Open
Abstract
Crocodilepox virus is a large dsDNA virus belonging to the genus Crocodylidpoxvirus, which infects a wide range of host species in the order Crocodylia worldwide. Here, we present genome sequences for a novel saltwater crocodilepox virus, with two subtypes (SwCRV-1 and -2), isolated from the Australian saltwater crocodile. Affected belly skins of juvenile saltwater crocodiles were used to sequence complete viral genomes, and perform electron microscopic analysis that visualized immature and mature virions. Analysis of the SwCRV genomes showed a high degree of sequence similarity to CRV (84.53% and 83.70%, respectively), with the novel SwCRV-1 and -2 complete genome sequences missing 5 and 6 genes respectively when compared to CRV, but containing 45 and 44 predicted unique genes. Similar to CRV, SwCRV also lacks the genes involved in virulence and host range, however, considering the presence of numerous hypothetical and or unique genes in the SwCRV genomes, it is completely reasonable that the genes encoding these functions are present but not recognized. Phylogenetic analysis suggested a monophyletic relationship between SwCRV and CRV, however, SwCRV is quite distinct from other chordopoxvirus genomes. These are the first SwCRV complete genome sequences isolated from saltwater crocodile skin lesions.
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Affiliation(s)
- Subir Sarker
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia.
| | - Sally R Isberg
- Centre for Crocodile Research, Noonamah, NT, Australia.,School of Psychological and Clinical Sciences, Charles Darwin University, Darwin, NT, Australia
| | - Natalie L Milic
- School of Psychological and Clinical Sciences, Charles Darwin University, Darwin, NT, Australia
| | - Peter Lock
- La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, Australia
| | - Karla J Helbig
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Bundoora, VIC 3086, Australia
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20
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Deeg CM, Chow CET, Suttle CA. The kinetoplastid-infecting Bodo saltans virus (BsV), a window into the most abundant giant viruses in the sea. eLife 2018; 7:33014. [PMID: 29582753 PMCID: PMC5871332 DOI: 10.7554/elife.33014] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 02/22/2018] [Indexed: 01/24/2023] Open
Abstract
Giant viruses are ecologically important players in aquatic ecosystems that have challenged concepts of what constitutes a virus. Herein, we present the giant Bodo saltans virus (BsV), the first characterized representative of the most abundant group of giant viruses in ocean metagenomes, and the first isolate of a klosneuvirus, a subgroup of the Mimiviridae proposed from metagenomic data. BsV infects an ecologically important microzooplankton, the kinetoplastid Bodo saltans. Its 1.39 Mb genome encodes 1227 predicted ORFs, including a complex replication machinery. Yet, much of its translational apparatus has been lost, including all tRNAs. Essential genes are invaded by homing endonuclease-encoding self-splicing introns that may defend against competing viruses. Putative anti-host factors show extensive gene duplication via a genomic accordion indicating an ongoing evolutionary arms race and highlighting the rapid evolution and genomic plasticity that has led to genome gigantism and the enigma that is giant viruses.
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Affiliation(s)
- Christoph M Deeg
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | - Cheryl-Emiliane T Chow
- Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada
| | - Curtis A Suttle
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada.,Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, Canada.,Department of Botany, University of British Columbia, Vancouver, Canada.,Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, Canada
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21
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Identification of Poxvirus Genome Uncoating and DNA Replication Factors with Mutually Redundant Roles. J Virol 2018; 92:JVI.02152-17. [PMID: 29343579 DOI: 10.1128/jvi.02152-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 01/02/2018] [Indexed: 12/13/2022] Open
Abstract
Genome uncoating is essential for replication of most viruses. For poxviruses, the process is divided into two stages: removal of the envelope, allowing early gene expression, and breaching of the core wall, allowing DNA release, replication, and late gene expression. Subsequent studies showed that the host proteasome and the viral D5 protein, which has an essential role in DNA replication, are required for vaccinia virus (VACV) genome uncoating. In a search for additional VACV uncoating proteins, we noted a report that described a defect in DNA replication and late expression when the gene encoding a 68-kDa ankyrin repeat/F-box protein (68k-ank), associated with the cellular SCF (Skp1, cullin1, F-box-containing complex) ubiquitin ligase complex, was deleted from the attenuated modified vaccinia virus Ankara (MVA). Here we showed that the 68k-ank deletion mutant exhibited diminished genome uncoating, formation of DNA prereplication sites, and degradation of viral cores as well as an additional, independent defect in DNA synthesis. Deletion of the 68k-ank homolog of VACV strain WR, however, was without effect, suggesting the existence of compensating genes. By inserting VACV genes into an MVA 68k-ank deletion mutant, we discovered that M2, a member of the poxvirus immune evasion (PIE) domain superfamily and a regulator of NF-κB, and C5, a member of the BTB/Kelch superfamily associated with cullin-3-based ligase complexes, independently rescued the 68k-ank deletion phenotype. Thus, poxvirus uncoating and DNA replication are intertwined processes involving at least three viral proteins with mutually redundant functions in addition to D5.IMPORTANCE Poxviruses comprise a family of large DNA viruses that infect vertebrates and invertebrates and cause diseases of medical and zoological importance. Poxviruses, unlike most other DNA viruses, replicate in the cytoplasm, and their large genomes usually encode 200 or more proteins with diverse functions. About 90 genes may be essential for chordopoxvirus replication based either on their conservation or individual gene deletion studies. However, this number may underestimate the true number of essential functions because of redundancy. Here we show that any one of three seemingly unrelated and individually nonessential proteins is required for the incompletely understood processes of genome uncoating and DNA replication, an example of synthetic lethality. Thus, poxviruses appear to have a complex genetic interaction network that has not been fully appreciated and which will require multifactor deletion screens to assess.
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22
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Ankyrin Repeat Proteins of Orf Virus Influence the Cellular Hypoxia Response Pathway. J Virol 2016; 91:JVI.01430-16. [PMID: 27795413 DOI: 10.1128/jvi.01430-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/18/2016] [Indexed: 11/20/2022] Open
Abstract
Hypoxia-inducible factor (HIF) is a transcriptional activator with a central role in regulating cellular responses to hypoxia. It is also emerging as a major target for viral manipulation of the cellular environment. Under normoxic conditions, HIF is tightly suppressed by the activity of oxygen-dependent prolyl and asparaginyl hydroxylases. The asparaginyl hydroxylase active against HIF, factor inhibiting HIF (FIH), has also been shown to hydroxylate some ankyrin repeat (ANK) proteins. Using bioinformatic analysis, we identified the five ANK proteins of the parapoxvirus orf virus (ORFV) as potential substrates of FIH. Consistent with this prediction, coimmunoprecipitation of FIH was detected with each of the ORFV ANK proteins, and for one representative ORFV ANK protein, the interaction was shown to be dependent on the ANK domain. Immunofluorescence studies revealed colocalization of FIH and the viral ANK proteins. In addition, mass spectrometry confirmed that three of the five ORFV ANK proteins are efficiently hydroxylated by FIH in vitro While FIH levels were unaffected by ORFV infection, transient expression of each of the ORFV ANK proteins resulted in derepression of HIF-1α activity in reporter gene assays. Furthermore, ORFV-infected cells showed upregulated HIF target gene expression. Our data suggest that sequestration of FIH by ORFV ANK proteins leads to derepression of HIF activity. These findings reveal a previously unknown mechanism of viral activation of HIF that may extend to other members of the poxvirus family. IMPORTANCE The protein-protein binding motif formed from multiple repeats of the ankyrin motif is common among chordopoxviruses. However, information on the roles of these poxviral ankyrin repeat (ANK) proteins remains limited. Our data indicate that the parapoxvirus orf virus (ORFV) is able to upregulate hypoxia-inducible factor (HIF) target gene expression. This response is mediated by the viral ANK proteins, which sequester the HIF regulator FIH (factor inhibiting HIF). This is the first demonstration of any viral protein interacting directly with FIH. Our data reveal a new mechanism by which viruses reprogram HIF, a master regulator of cellular metabolism, and also show a new role for the ANK family of poxvirus proteins.
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23
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Levin RA, Voolstra CR, Weynberg KD, van Oppen MJH. Evidence for a role of viruses in the thermal sensitivity of coral photosymbionts. ISME JOURNAL 2016; 11:808-812. [PMID: 27911439 DOI: 10.1038/ismej.2016.154] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 09/04/2016] [Accepted: 09/18/2016] [Indexed: 11/10/2022]
Abstract
Symbiodinium, the dinoflagellate photosymbiont of corals, is posited to become more susceptible to viral infections when heat-stressed. To investigate this hypothesis, we mined transcriptome data of a thermosensitive and a thermotolerant type C1 Symbiodinium population at ambient (27 °C) and elevated (32°C) temperatures. We uncovered hundreds of transcripts from nucleocytoplasmic large double-stranded DNA viruses (NCLDVs) and the genome of a novel positive-sense single-stranded RNA virus (+ssRNAV). In the transcriptome of the thermosensitive population only, +ssRNAV transcripts had remarkable expression levels in the top 0.03% of all transcripts at 27 °C, but at 32 °C, expression levels of +ssRNAV transcripts decreased, while expression levels of anti-viral transcripts increased. In both transcriptomes, expression of NCLDV transcripts increased at 32 °C, but thermal induction of NCLDV transcripts involved in DNA manipulation was restricted to the thermosensitive population. Our findings reveal that viruses infecting Symbiodinium are affected by heat stress and may contribute to Symbiodinium thermal sensitivity.
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Affiliation(s)
- Rachel Ashley Levin
- Centre for Marine Bio-Innovation, The University of New South Wales (UNSW), Sydney, NSW, Australia.,School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, NSW, Australia.,Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
| | - Christian Robert Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, 4700 King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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24
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Efficiency in Complexity: Composition and Dynamic Nature of Mimivirus Replication Factories. J Virol 2016; 90:10039-10047. [PMID: 27581975 DOI: 10.1128/jvi.01319-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 08/18/2016] [Indexed: 11/20/2022] Open
Abstract
The recent discovery of multiple giant double-stranded DNA (dsDNA) viruses blurred the consensual distinction between viruses and cells due to their size, as well as to their structural and genetic complexity. A dramatic feature revealed by these viruses as well as by many positive-strand RNA viruses is their ability to rapidly form elaborate intracellular organelles, termed "viral factories," where viral progeny are continuously generated. Here we report the first isolation of viral factories at progressive postinfection time points. The isolated factories were subjected to mass spectrometry-based proteomics, bioinformatics, and imaging analyses. These analyses revealed that numerous viral proteins are present in the factories but not in mature virions, thus implying that multiple and diverse proteins are required to promote the efficiency of viral factories as "production lines" of viral progeny. Moreover, our results highlight the dynamic and highly complex nature of viral factories, provide new and general insights into viral infection, and substantiate the intriguing notion that viral factories may represent the living state of viruses. IMPORTANCE Large dsDNA viruses such as vaccinia virus and the giant mimivirus, as well as many positive-strand RNA viruses, generate elaborate cytoplasmic organelles in which the multiple and diverse transactions required for viral replication and assembly occur. These organelles, which were termed "viral factories," are attracting much interest due to the increasing realization that the rapid and continuous production of viral progeny is a direct outcome of the elaborate structure and composition of the factories, which act as efficient production lines. To get new insights into the nature and function of viral factories, we devised a method that allows, for the first time, the isolation of these organelles. Analyses of the isolated factories generated at different times postinfection by mass spectrometry-based proteomics provide new perceptions of their role and reveal the highly dynamic nature of these organelles.
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Bravo Cruz AG, Shisler JL. Vaccinia virus K1 ankyrin repeat protein inhibits NF-κB activation by preventing RelA acetylation. J Gen Virol 2016; 97:2691-2702. [DOI: 10.1099/jgv.0.000576] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Ariana G. Bravo Cruz
- Department of Microbiology, University of Illinois, 601 S. Goodwin Avenue, Urbana, IL 61801, USA
| | - Joanna L. Shisler
- Department of Microbiology, University of Illinois, 601 S. Goodwin Avenue, Urbana, IL 61801, USA
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Zhao J, He S, Minassian A, Li J, Feng P. Recent advances on viral manipulation of NF-κB signaling pathway. Curr Opin Virol 2015; 15:103-11. [PMID: 26385424 PMCID: PMC4688235 DOI: 10.1016/j.coviro.2015.08.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/09/2015] [Accepted: 08/26/2015] [Indexed: 12/18/2022]
Abstract
NF-κB transcription factors regulate the expression of hundreds of genes primarily involved in immune responses. Signaling events leading to NF-κB activation constitute a major antiviral immune pathway. To replicate and persist within their hosts, viruses have evolved diverse strategies to evade and exploit cellular NF-κB immune signaling cascades for their benefit. We summarize recent studies concerning viral manipulation of the NF-κB signaling pathway downstream of pattern recognition receptors. Signal transduction mediated by pattern recognition receptors is a research frontier for both infectious disease and innate immunology.
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Affiliation(s)
- Jun Zhao
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, United States
| | - Shanping He
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, United States
| | - Arlet Minassian
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, United States
| | - Junhua Li
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, United States
| | - Pinghui Feng
- Department of Molecular Microbiology and Immunology, Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, United States.
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Orientia tsutsugamushi Strain Ikeda Ankyrin Repeat-Containing Proteins Recruit SCF1 Ubiquitin Ligase Machinery via Poxvirus-Like F-Box Motifs. J Bacteriol 2015; 197:3097-109. [PMID: 26170417 DOI: 10.1128/jb.00276-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 07/10/2015] [Indexed: 12/20/2022] Open
Abstract
UNLABELLED A rising theme among intracellular microbes is the delivery of ankyrin repeat-containing effectors (Anks) that interact with target proteins to co-opt host cell functions. Orientia tsutsugamushi, an obligate intracellular bacterium and the etiologic agent of scrub typhus, encodes one of the largest Ank repertoires of any sequenced microorganism. They have been previously identified as type 1 secretion system substrates. Here, in silico and manual sequence analyses revealed that a large proportion of O. tsutsugamushi strain Ikeda Anks bear a eukaryotic/poxvirus-like F-box motif, which is known to recruit host cell SCF1 ubiquitin ligase machinery. We assessed the Anks for the ability to serve as F-box proteins. Coimmunoprecipitation assays demonstrated that F-box-containing Anks interact with overexpressed and/or endogenous SCF1 components. When coexpressed with FLAG-Ank4_01 or FLAG-Ank9, a glutathione S-transferase (GST)-tagged version of the SCF1 component SKP1 localized to subcellular sites of FLAG-Ank accumulation. The abilities of recombinant Anks to interact and colocalize with SKP1 were F-box dependent. GST-SKP1 precipitated O. tsutsugamushi-derived Ank9 from infected host cells, verifying both that the pathogen expresses Ank9 during infection and the protein's capability to bind SKP1. Aligning O. tsutsugamushi, poxviral, and eukaryotic F-box sequences delineated three F-box residues that are highly conserved and likely to be functionally important. Substitution of these residues ablated the ability of GFP-Ank9 to interact with GST-SKP1. These results demonstrate that O. tsutsugamushi strain Ikeda Anks can co-opt host cell polyubiquitination machinery, provide the first evidence that an O. tsutsugamushi Ank does so during infection, and advance overall understanding of microbial F-box proteins. IMPORTANCE Ankyrin repeat-containing proteins (Anks) are important virulence factors of intracellular bacteria that mediate protein-protein interactions with host cell targets. Orientia tsutsugamushi, which causes a debilitating infection called scrub typhus in one of the most densely populated regions of the world, encodes one of the largest Ank armamentariums of any sequenced bacterium. This study demonstrates that O. tsutsugamushi strain Ikeda Anks also bear F-box motifs that interact with host cell polyubiquitination machinery. By proving that an Orientia-derived Ank interacts with SKP1 in infected cells, this evidences the first bona fide Orientia effector and the first example of an endogenous F-box-containing Ank-mammalian-host ligand interaction for any intracellular bacterium. Also, importantly, this work identifies key residues that are essential for microbial F-box function.
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Huang T, Tulman ER, Diel DG, Khatiwada S, Sims W, Edwards JF, Wen X, Kutish GF, Rock DL, Delhon G. Coinfection with multiple strains of bovine papular stomatitis virus. Arch Virol 2015; 160:1527-32. [PMID: 25804193 DOI: 10.1007/s00705-015-2394-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 03/06/2015] [Indexed: 10/23/2022]
Abstract
Bovine papular stomatitis virus (BPSV) infects cattle and, occupationally, humans. Prevalent subclinical infections, frequent reinfections, and virus persistence in healthy animals compound a poorly understood, but likely complex, scenario of BPSV perpetuation and transmission in nature. Here, we report the isolation of multiple BPSV strains coinfecting a single animal. Whole-genome analysis of isolated BPSV strains revealed genomic variability likely affecting virus virulence and infectivity. Further, incongruent phylogenetic relationships between viruses suggested genomic recombination. These results have significant implications for parapoxvirus infection biology and virus evolution in nature.
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Affiliation(s)
- Tao Huang
- Laboratory of Animal Infectious Disease and Microarray/Key Laboratory of Animal Disease and Human Health of Sichuan Province, College of Animal Veterinary Medicine, Sichuan Agricultural University, Yaan, China
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Herbert MH, Squire CJ, Mercer AA. Poxviral ankyrin proteins. Viruses 2015; 7:709-38. [PMID: 25690795 PMCID: PMC4353913 DOI: 10.3390/v7020709] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/05/2015] [Accepted: 02/09/2015] [Indexed: 02/08/2023] Open
Abstract
Multiple repeats of the ankyrin motif (ANK) are ubiquitous throughout the kingdoms of life but are absent from most viruses. The main exception to this is the poxvirus family, and specifically the chordopoxviruses, with ANK repeat proteins present in all but three species from separate genera. The poxviral ANK repeat proteins belong to distinct orthologue groups spread over different species, and align well with the phylogeny of their genera. This distribution throughout the chordopoxviruses indicates these proteins were present in an ancestral vertebrate poxvirus, and have since undergone numerous duplication events. Most poxviral ANK repeat proteins contain an unusual topology of multiple ANK motifs starting at the N-terminus with a C-terminal poxviral homologue of the cellular F-box enabling interaction with the cellular SCF ubiquitin ligase complex. The subtle variations between ANK repeat proteins of individual poxviruses suggest an array of different substrates may be bound by these protein-protein interaction domains and, via the F-box, potentially directed to cellular ubiquitination pathways and possible degradation. Known interaction partners of several of these proteins indicate that the NF-κB coordinated anti-viral response is a key target, whilst some poxviral ANK repeat domains also have an F-box independent affect on viral host-range.
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Affiliation(s)
- Michael H Herbert
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand.
| | - Christopher J Squire
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand.
| | - Andrew A Mercer
- Virus Research Unit, Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand.
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Ectromelia virus encodes a family of Ankyrin/F-box proteins that regulate NFκB. Virology 2014; 468-470:351-362. [DOI: 10.1016/j.virol.2014.08.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 08/17/2014] [Accepted: 08/29/2014] [Indexed: 12/18/2022]
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Interaction of infectious spleen and kidney necrosis virus ORF119L with PINCH leads to dominant-negative inhibition of integrin-linked kinase and cardiovascular defects in zebrafish. J Virol 2014; 89:763-75. [PMID: 25355883 DOI: 10.1128/jvi.01955-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
UNLABELLED Infectious spleen and kidney necrosis virus (ISKNV) is the type species of the Megalocytivirus genus, Iridoviridae family, causing a severe systemic disease with high mortality in mandarin fish (Siniperca chuatsi) in China and Southeast Asia. At present, the pathogenesis of ISKNV infection is still not fully understood. Based on a genome-wide bioinformatics analysis of ISKNV-encoded proteins, we found that ISKNV open reading frame 119L (ORF119L) is predicted to encode a three-ankyrin-repeat (3ANK)-domain-containing protein, which shows high similarity to the dominant negative form of integrin-linked kinase (ILK); i.e., viral ORF119L lacks the ILK kinase domain. Thus, we speculated that viral ORF119L might affect the host ILK complex. Here, we demonstrated that viral ORF119L directly interacts with particularly interesting Cys-His-rich protein (PINCH) and affects the host ILK-PINCH interaction in vitro in fathead minnow (FHM) cells. In vivo ORF119L overexpression in zebrafish (Danio rerio) embryos resulted in myocardial dysfunctions with disintegration of the sarcomeric Z disk. Importantly, ORF119L overexpression in zebrafish highly resembles the phenotype of endogenous ILK inhibition, either by overexpressing a dominant negative form of ILK or by injecting an ILK antisense morpholino oligonucleotide. Intriguingly, ISKNV-infected mandarin fish develop disorganized sarcomeric Z disks in cardiomyocytes. Furthermore, phosphorylation of AKT, a downstream effector of ILK, was remarkably decreased in ORF119L-overexpressing zebrafish embryos. With these results, we show that ISKNV ORF119L acts as a domain-negative inhibitor of the host ILK, providing a novel mechanism for the megalocytivirus pathogenesis. IMPORTANCE Our work is the first to show the role of a dominant negative inhibitor of the host ILK from ISKNV (an iridovirus). Mechanistically, the viral ORF119L directly binds to the host PINCH, attenuates the host PINCH-ILK interaction, and thus impairs ILK signaling. Intriguingly, ORF119L-overexpressing zebrafish embryos and ISKNV-infected mandarin fish develop similar disordered sarcomeric Z disks in cardiomyocytes. These findings provide a novel mechanism for megalocytivirus pathogenesis.
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Chlorovirus Skp1-binding ankyrin repeat protein interplay and mimicry of cellular ubiquitin ligase machinery. J Virol 2014; 88:13798-810. [PMID: 25253343 DOI: 10.1128/jvi.02109-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The ubiquitin-proteasome system is targeted by many viruses that have evolved strategies to redirect host ubiquitination machinery. Members of the genus Chlorovirus are proposed to share an ancestral lineage with a broader group of related viruses, nucleo-cytoplasmic large DNA viruses (NCLDV). Chloroviruses encode an Skp1 homolog and ankyrin repeat (ANK) proteins. Several chlorovirus-encoded ANK repeats contain C-terminal domains characteristic of cellular F-boxes or related NCLDV chordopox PRANC (pox protein repeats of ankyrin at C-terminal) domains. These observations suggested that this unique combination of Skp1 and ANK repeat proteins might form complexes analogous to the cellular Skp1-Cul1-F-box (SCF) ubiquitin ligase complex. We identified two ANK proteins from the prototypic chlorovirus Paramecium bursaria chlorella virus-1 (PBCV-1) that functioned as binding partners for the virus-encoded Skp1, proteins A682L and A607R. These ANK proteins had a C-terminal Skp1 interactional motif that functioned similarly to cellular F-box domains. A C-terminal motif of ANK protein A682L binds Skp1 proteins from widely divergent species. Yeast two-hybrid analyses using serial domain deletion constructs confirmed the C-terminal localization of the Skp1 interactional motif in PBCV-1 A682L. ANK protein A607R represents an ANK family with one member present in all 41 sequenced chloroviruses. A comprehensive phylogenetic analysis of these related ANK and viral Skp1 proteins suggested partnered function tailored to the host alga or common ancestral heritage. Here, we show protein-protein interaction between corresponding family clusters of virus-encoded ANK and Skp1 proteins from three chlorovirus types. Collectively, our results indicate that chloroviruses have evolved complementing Skp1 and ANK proteins that mimic cellular SCF-associated proteins. IMPORTANCE Viruses have evolved ways to direct ubiquitination events in order to create environments conducive to their replication. As reported in the manuscript, the large chloroviruses encode several components involved in the SCF ubiquitin ligase complex including a viral Skp1 homolog. Studies on how chloroviruses manipulate their host algal ubiquitination system will provide insights toward viral protein mimicry, substrate recognition, and key interactive domains controlling selective protein degradation. These findings may also further understanding of the evolution of other large DNA viruses, like poxviruses, that are reported to share the same monophyly lineage as chloroviruses.
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Mottet K, Bareiss B, Milne CD, Barry M. The poxvirus encoded ubiquitin ligase, p28, is regulated by proteasomal degradation and autoubiquitination. Virology 2014; 468-470:363-378. [PMID: 25240226 DOI: 10.1016/j.virol.2014.08.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 08/19/2014] [Accepted: 08/23/2014] [Indexed: 11/30/2022]
Abstract
Virus manipulation of the ubiquitin-proteasome system has become increasingly apparent. Ubiquitin is a 76 amino acid protein that is post-translationally conjugated to target proteins, while poly-ubiquitination subsequently leads to degradation via the 26S proteasome. Target specificity is determined by a large family of ubiquitin ligases. Poxviruses encode p28, a highly conserved ubiquitin ligase expressed in a wide range of poxviruses (J. Virol. 79:597). Here we investigate the relationship between p28 and ubiquitination. Confocal microscopy indicated that orthologs of p28 co-localized with ubiquitin at the virus factory. Flow cytometry assays further demonstrated that p28 was regulated by proteasomal degradation. Moreover, when the ubiquitin ligase activity of p28 was disrupted by mutating the RING domain conjugated ubiquitin still localized to the viral factories, indicating that an unknown ubiquitin ligase(s) was responsible for regulating p28. Our observations indicate that p28 is a ubiquitin ligase that is regulated by ubiquitination and proteasomal degradation.
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Affiliation(s)
- Kelly Mottet
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, 621 HMRC, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
| | - Bettina Bareiss
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, 621 HMRC, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
| | - Craig D Milne
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, 621 HMRC, University of Alberta, Edmonton, Alberta, Canada T6G 2S2
| | - Michele Barry
- Li Ka Shing Institute of Virology, Department of Medical Microbiology and Immunology, 621 HMRC, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.
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Min CK, Kwon YJ, Ha NY, Cho BA, Kim JM, Kwon EK, Kim YS, Choi MS, Kim IS, Cho NH. Multiple Orientia tsutsugamushi ankyrin repeat proteins interact with SCF1 ubiquitin ligase complex and eukaryotic elongation factor 1 α. PLoS One 2014; 9:e105652. [PMID: 25166298 PMCID: PMC4148323 DOI: 10.1371/journal.pone.0105652] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 07/22/2014] [Indexed: 11/30/2022] Open
Abstract
Background Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular bacterium. Previously, a large number of genes that encode proteins containing eukaryotic protein-protein interaction motifs such as ankyrin-repeat (Ank) domains were identified in the O. tsutsugamushi genome. However, little is known about the Ank protein function in O. tsutsugamushi. Methodology/Principal Findings To characterize the function of Ank proteins, we investigated a group of Ank proteins containing an F-box–like domain in the C-terminus in addition to the Ank domains. All nine selected ank genes were expressed at the transcriptional level in host cells infected with O. tsutsugamushi, and specific antibody responses against three Ank proteins were detected in the serum from human patients, indicating an active expression of the bacterial Ank proteins post infection. When ectopically expressed in HeLa cells, the Ank proteins of O. tsutsugamushi were consistently found in the nucleus and/or cytoplasm. In GST pull-down assays, multiple Ank proteins specifically interacted with Cullin1 and Skp1, core components of the SCF1 ubiquitin ligase complex, as well as the eukaryotic elongation factor 1 α (EF1α). Moreover, one Ank protein co-localized with the identified host targets and induced downregulation of EF1α potentially via enhanced ubiquitination. The downregulation of EF1α was observed consistently in diverse host cell types infected with O. tsutsugamushi. Conclusion/Significance These results suggest that conserved targeting and subsequent degradation of EF1α by multiple O. tsutsugamushi Ank proteins could be a novel bacterial strategy for replication and/or pathogenesis during mammalian host infection.
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Affiliation(s)
- Chan-Ki Min
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ye-Jin Kwon
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Na-Young Ha
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Bon-A Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jo-Min Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Eun-Kyung Kwon
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yeon-Sook Kim
- Divisions of Infectious Diseases, Chungnam National University Hospital, Daejeon, Republic of Korea
| | - Myung-Sik Choi
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ik-Sang Kim
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Nam-Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Republic of Korea
- Institute of Endemic Disease, Seoul National University Medical Research Center and Bundang Hospital, Seoul, Republic of Korea
- * E-mail:
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EVM005: an ectromelia-encoded protein with dual roles in NF-κB inhibition and virulence. PLoS Pathog 2014; 10:e1004326. [PMID: 25122471 PMCID: PMC4133408 DOI: 10.1371/journal.ppat.1004326] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 07/07/2014] [Indexed: 11/19/2022] Open
Abstract
Poxviruses contain large dsDNA genomes encoding numerous open reading frames that manipulate cellular signalling pathways and interfere with the host immune response. The NF-κB signalling cascade is an important mediator of innate immunity and inflammation, and is tightly regulated by ubiquitination at several key points. A critical step in NF-κB activation is the ubiquitination and degradation of the inhibitor of kappaB (IκBα), by the cellular SCFβ-TRCP ubiquitin ligase complex. We show here that upon stimulation with TNFα or IL-1β, Orthopoxvirus-infected cells displayed an accumulation of phosphorylated IκBα, indicating that NF-κB activation was inhibited during poxvirus infection. Ectromelia virus is the causative agent of lethal mousepox, a natural disease that is fatal in mice. Previously, we identified a family of four ectromelia virus genes (EVM002, EVM005, EVM154 and EVM165) that contain N-terminal ankyrin repeats and C-terminal F-box domains that interact with the cellular SCF ubiquitin ligase complex. Since degradation of IκBα is catalyzed by the SCFβ-TRCP ubiquitin ligase, we investigated the role of the ectromelia virus ankyrin/F-box protein, EVM005, in the regulation of NF-κB. Expression of Flag-EVM005 inhibited both TNFα- and IL-1β-stimulated IκBα degradation and p65 nuclear translocation. Inhibition of the NF-κB pathway by EVM005 was dependent on the F-box domain, and interaction with the SCF complex. Additionally, ectromelia virus devoid of EVM005 was shown to inhibit NF-κB activation, despite lacking the EVM005 open reading frame. Finally, ectromelia virus devoid of EVM005 was attenuated in both A/NCR and C57BL/6 mouse models, indicating that EVM005 is required for virulence and immune regulation in vivo. Poxviruses are large dsDNA viruses that are renowned for regulating cellular pathways and manipulating the host immune response, including the NF-κB pathway. NF-κB inhibition by poxviruses is a growing area of interest and this family of viruses has developed multiple mechanisms to manipulate the pathway. Here, we focus on regulation of the NF-κB pathway by ectromelia virus, the causative agent of mousepox. We demonstrate that ectromelia virus is a potent inhibitor of the NF-κB pathway. Previously, we identified a family of four ectromelia virus genes that contain N-terminal ankyrin repeats and a C-terminal F-box domain that interacts with the cellular SCF ubiquitin ligase. Significantly, expression of the ankyrin/F-box protein, EVM005, inhibited NF-κB, and the F-box domain was critical for NF-κB inhibition and interaction with the SCF complex. Ectromelia virus devoid of EVM005 still inhibited NF-κB, indicating that multiple gene products contribute to NF-κB inhibition. Importantly, mice infected with ectromelia virus lacking EVM005 had a robust immune response, leading to viral clearance during infection. The data present two mechanisms, one in which EVM005 inhibits NF-κB activation through manipulation of the host SCF ubiquitin ligase complex, and an additional, NF-κB-independent mechanism that drives virulence.
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36
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Maluquer de Motes C, Schiffner T, Sumner RP, Smith GL. Vaccinia virus virulence factor N1 can be ubiquitylated on multiple lysine residues. J Gen Virol 2014; 95:2038-2049. [PMID: 24914067 PMCID: PMC4135091 DOI: 10.1099/vir.0.065664-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Ubiquitylation is a covalent post-translational modification that regulates protein stability and is involved in many biological functions. Proteins may be modified with mono-ubiquitin or ubiquitin chains. Viruses have evolved multiple mechanisms to perturb the cell ubiquitin system and manipulate it to their own benefit. Here, we report ubiquitylation of vaccinia virus (VACV) protein N1. N1 is an inhibitor of the nuclear factor NF-κB and apoptosis that contributes to virulence, has a Bcl-2-like fold, and is highly conserved amongst orthopoxviruses. The interaction between N1 and ubiquitin occurs at endogenous protein levels during VACV infection and following ectopic expression of N1. Biochemical analysis demonstrated that N1 is covalently ubiquitylated, and heterodimers of ubiquitylated and non-ubiquitylated N1 monomers were identified, suggesting that ubiquitylation does not inhibit N1 dimerization. Studies with other VACV Bcl-2 proteins, such as C6 or B14, revealed that although these proteins also interact with ubiquitin, these interactions are non-covalent. Finally, mutagenesis of N1 showed that ubiquitylation occurs in a conventional lysine-dependent manner at multiple acceptor sites because only an N1 allele devoid of lysine residues remained unmodified. Taken together, we described a previously uncharacterized modification of the VACV protein N1 that provided a new layer of complexity to the biology of this virulence factor, and provided another example of the intricate interplay between poxviruses and the host ubiquitin system.
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Affiliation(s)
- Carlos Maluquer de Motes
- Department of Virology, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK.,Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Torben Schiffner
- Department of Virology, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
| | - Rebecca P Sumner
- Department of Virology, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK.,Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
| | - Geoffrey L Smith
- Department of Virology, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK.,Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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Lacek K, Bauer B, Bieńkowska-Szewczyk K, Rziha HJ. Orf virus (ORFV) ANK-1 protein mitochondrial localization is mediated by ankyrin repeat motifs. Virus Genes 2014; 49:68-79. [PMID: 24743940 DOI: 10.1007/s11262-014-1069-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 04/03/2014] [Indexed: 10/25/2022]
Abstract
Orf virus (ORFV) strain D1701-V, a Parapoxvirus belonging to the family Poxviridae, became attractive as a novel virus vector system that we successfully used for the generation of recombinant vaccines. Therefore, the identification of viral genes involved in host tropisms or immune modulation is of great interest, as for instance the ORFV-encoded ankyrin-repeat (AR) containing proteins. The present study shows for the first time that the ANK-1 designated gene product of ORFV126 is targeted to mitochondria of ORFV-infected and in ANK-1 transiently expressing cells. Taking advantage of ANK-1 EGFP fusion proteins and confocal fluorescence microscopy mutational and deletion analyses indicated the importance of AR8 and AR9, which may contain a novel class of mitochondria-targeting sequence (MTS) in the central to C-terminal part of this AR-containing protein. The fluorescent findings were corroborated by cell fractionation and Western blotting experiments. The presented results open the avenue for more detailed investigations on cellular binding partners and the function of ANK-1 in viral replication or virulence.
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Affiliation(s)
- Krzysztof Lacek
- Laboratory of Virus Molecular Biology, University of Gdańsk, 80-822, Gdańsk, Poland
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Initial characterization of vaccinia virus B4 suggests a role in virus spread. Virology 2014; 456-457:108-20. [PMID: 24889230 DOI: 10.1016/j.virol.2014.03.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 03/04/2014] [Accepted: 03/19/2014] [Indexed: 11/21/2022]
Abstract
Currently, little is known about the ankyrin/F-box protein B4. Here, we report that B4R-null viruses exhibited reduced plaque size in tissue culture, and decreased ability to spread, as assessed by multiple-step growth analysis. Electron microscopy indicated that B4R-null viruses still formed mature and extracellular virions; however, there was a slight decrease of virions released into the media following deletion of B4R. Deletion of B4R did not affect the ability of the virus to rearrange actin; however, VACV811, a large vaccinia virus deletion mutant missing 55 open reading frames, had decreased ability to produce actin tails. Using ectromelia virus, a natural mouse pathogen, we demonstrated that virus devoid of EVM154, the B4R homolog, showed decreased spread to organs and was attenuated during infection. This initial characterization suggests that B4 may play a role in virus spread, and that other unidentified mediators of actin tail formation may exist in vaccinia virus.
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39
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Hosamani M, Scagliarini A, Bhanuprakash V, McInnes CJ, Singh RK. Orf: an update on current research and future perspectives. Expert Rev Anti Infect Ther 2014; 7:879-93. [PMID: 19735227 DOI: 10.1586/eri.09.64] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Madhusudan Hosamani
- Indian Veterinary Research Institute, Mukteswar-263138, Nainital Distt., India and Indian Veterinary Research Institute, Hebbal, Bangalore-24, India.
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Abstract
Subclinical immunosuppression in chickens is an important but often underestimated factor in the subsequent development of clinical disease. Immunosuppression can be caused by pathogens such as chicken infectious anemia virus, infectious bursal disease virus, reovirus, and some retroviruses (e.g., reticuloendotheliosis virus). Mycotoxins and stress, often caused by poor management practices, can also cause immunosuppression. The effects on the innate and acquired immune responses and the mechanisms by which mycotoxins, stress and infectious agents cause immunosuppression are discussed. Immunoevasion is a common ploy by which viruses neutralize or evade immune responses. DNA viruses such as herpesvirus and poxvirus have multiple genes, some of them host-derived, which interfere with effective innate or acquired immune responses. RNA viruses may escape acquired humoral and cellular immune responses by mutations in protective antigenic epitopes (e.g., avian influenza viruses), while accessory non-structural proteins or multi-functional structural proteins interfere with the interferon system (e.g., Newcastle disease virus).
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Haller SL, Peng C, McFadden G, Rothenburg S. Poxviruses and the evolution of host range and virulence. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2014; 21:15-40. [PMID: 24161410 PMCID: PMC3945082 DOI: 10.1016/j.meegid.2013.10.014] [Citation(s) in RCA: 174] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 10/15/2013] [Accepted: 10/15/2013] [Indexed: 11/22/2022]
Abstract
Poxviruses as a group can infect a large number of animals. However, at the level of individual viruses, even closely related poxviruses display highly diverse host ranges and virulence. For example, variola virus, the causative agent of smallpox, is human-specific and highly virulent only to humans, whereas related cowpox viruses naturally infect a broad spectrum of animals and only cause relatively mild disease in humans. The successful replication of poxviruses depends on their effective manipulation of the host antiviral responses, at the cellular-, tissue- and species-specific levels, which constitutes a molecular basis for differences in poxvirus host range and virulence. A number of poxvirus genes have been identified that possess host range function in experimental settings, and many of these host range genes target specific antiviral host pathways. Herein, we review the biology of poxviruses with a focus on host range, zoonotic infections, virulence, genomics and host range genes as well as the current knowledge about the function of poxvirus host range factors and how their interaction with the host innate immune system contributes to poxvirus host range and virulence. We further discuss the evolution of host range and virulence in poxviruses as well as host switches and potential poxvirus threats for human and animal health.
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Affiliation(s)
- Sherry L Haller
- Laboratory for Host-Specific Virology, Division of Biology, Kansas State University, KS 66506, USA
| | - Chen Peng
- Laboratory for Host-Specific Virology, Division of Biology, Kansas State University, KS 66506, USA
| | - Grant McFadden
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32610, USA
| | - Stefan Rothenburg
- Laboratory for Host-Specific Virology, Division of Biology, Kansas State University, KS 66506, USA.
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Muniz JRC, Guo K, Kershaw NJ, Ayinampudi V, von Delft F, Babon JJ, Bullock AN. Molecular architecture of the ankyrin SOCS box family of Cul5-dependent E3 ubiquitin ligases. J Mol Biol 2013; 425:3166-77. [PMID: 23806657 PMCID: PMC3779351 DOI: 10.1016/j.jmb.2013.06.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 01/30/2023]
Abstract
Multi-subunit Cullin-RING E3 ligases often use repeat domain proteins as substrate-specific adaptors. Structures of these macromolecular assemblies are determined for the F-box-containing leucine-rich repeat and WD40 repeat families, but not for the suppressor of cytokine signaling (SOCS)-box-containing ankyrin repeat proteins (ASB1-18), which assemble with Elongins B and C and Cul5. We determined the crystal structures of the ternary complex of ASB9-Elongin B/C as well as the interacting N-terminal domain of Cul5 and used structural comparisons to establish a model for the complete Cul5-based E3 ligase. The structures reveal a distinct architecture of the ASB9 complex that positions the ankyrin domain coaxial to the SOCS box-Elongin B/C complex and perpendicular to other repeat protein complexes. This alternative architecture appears favorable to present the ankyrin domain substrate-binding site to the E2-ubiquitin, while also providing spacing suitable for bulky ASB9 substrates, such as the creatine kinases. The presented Cul5 structure also differs from previous models and deviates from other Cullins via a rigid-body rotation between Cullin repeats. This work highlights the adaptability of repeat domain proteins as scaffolds in substrate recognition and lays the foundation for future structure-function studies of this important E3 family.
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Affiliation(s)
- João R C Muniz
- Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
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Pilar AVC, Reid-Yu SA, Cooper CA, Mulder DT, Coombes BK. Active modification of host inflammation by Salmonella. Gut Microbes 2013; 4:140-5. [PMID: 23333857 PMCID: PMC3595074 DOI: 10.4161/gmic.23361] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The dampening of host immune responses is a critical aspect of pathogenesis for the enteropathogen Salmonella enterica. Our laboratory has recently described a role for the secreted effector GogB in disruption of NFκB activation and limitation of the host inflammatory response to infection. GogB alters the NFκB pathway by preventing IκB degradation by the host SCF E3 ubiquitin ligase, through an interaction with Skp1 and FBXO22. The prevention of NFκB activation through this interaction dampens the host inflammatory response in the gut, which in turn limits the damage to host tissues during chronic infection. In this addendum, we summarize these recent findings and discuss their implications and impact in the area of host-pathogen interactions.
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Genetic screen of a library of chimeric poxviruses identifies an ankyrin repeat protein involved in resistance to the avian type I interferon response. J Virol 2013; 87:5028-40. [PMID: 23427151 DOI: 10.1128/jvi.02738-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Viruses must be able to resist host innate responses, especially the type I interferon (IFN) response. They do so by preventing the induction or activity of IFN and/or by resisting the antiviral effectors that it induces. Poxviruses are no exception, with many mechanisms identified whereby mammalian poxviruses, notably, vaccinia virus (VACV), but also cowpox and myxoma viruses, are able to evade host IFN responses. Similar mechanisms have not been described for avian poxviruses (avipoxviruses). Restricted for permissive replication to avian hosts, they have received less attention; moreover, the avian host responses are less well characterized. We show that the prototypic avipoxvirus, fowlpox virus (FWPV), is highly resistant to the antiviral effects of avian IFN. A gain-of-function genetic screen identified fpv014 to contribute to increased resistance to exogenous recombinant chicken alpha IFN (ChIFN1). fpv014 is a member of the large family of poxvirus (especially avipoxvirus) genes that encode proteins containing N-terminal ankyrin repeats (ANKs) and C-terminal F-box-like motifs. By binding the Skp1/cullin-1 complex, the F box in such proteins appears to target ligands bound by the ANKs for ubiquitination. Mass spectrometry and immunoblotting demonstrated that tandem affinity-purified, tagged fpv014 was complexed with chicken cullin-1 and Skp1. Prior infection with an fpv014-knockout mutant of FWPV still blocked transfected poly(I·C)-mediated induction of the beta IFN (ChIFN2) promoter as effectively as parental FWPV, but the mutant was more sensitive to exogenous ChIFN1. Therefore, unlike the related protein fpv012, fpv014 does not contribute to the FWPV block to induction of ChIFN2 but does confer resistance to an established antiviral state.
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Bratke KA, McLysaght A, Rothenburg S. A survey of host range genes in poxvirus genomes. INFECTION GENETICS AND EVOLUTION 2012; 14:406-25. [PMID: 23268114 DOI: 10.1016/j.meegid.2012.12.002] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 12/01/2012] [Accepted: 12/06/2012] [Indexed: 12/17/2022]
Abstract
Poxviruses are widespread pathogens, which display extremely different host ranges. Whereas some poxviruses, including variola virus, display narrow host ranges, others such as cowpox viruses naturally infect a wide range of mammals. The molecular basis for differences in host range are poorly understood but apparently depend on the successful manipulation of the host antiviral response. Some poxvirus genes have been shown to confer host tropism in experimental settings and are thus called host range factors. Identified host range genes include vaccinia virus K1L, K3L, E3L, B5R, C7L and SPI-1, cowpox virus CP77/CHOhr, ectromelia virus p28 and 022, and myxoma virus T2, T4, T5, 11L, 13L, 062R and 063R. These genes encode for ankyrin repeat-containing proteins, tumor necrosis factor receptor II homologs, apoptosis inhibitor T4-related proteins, Bcl-2-related proteins, pyrin domain-containing proteins, cellular serine protease inhibitors (serpins), short complement-like repeats containing proteins, KilA-N/RING domain-containing proteins, as well as inhibitors of the double-stranded RNA-activated protein kinase PKR. We conducted a systematic survey for the presence of known host range genes and closely related family members in poxvirus genomes, classified them into subgroups based on their phylogenetic relationship and correlated their presence with the poxvirus phylogeny. Common themes in the evolution of poxvirus host range genes are lineage-specific duplications and multiple independent inactivation events. Our analyses yield new insights into the evolution of poxvirus host range genes. Implications of our findings for poxvirus host range and virulence are discussed.
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Affiliation(s)
- Kirsten A Bratke
- Smurfit Institute of Genetics, University of Dublin, Trinity College, Dublin 2, Ireland
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Xu L, Luo ZQ. Cell biology of infection by Legionella pneumophila. Microbes Infect 2012; 15:157-67. [PMID: 23159466 DOI: 10.1016/j.micinf.2012.11.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/02/2012] [Accepted: 11/05/2012] [Indexed: 01/09/2023]
Abstract
Professional phagocytes digest internalized microorganisms by actively delivering them into the phagolysosomal compartment. Intravacuolar bacterial pathogens have evolved a variety of effective strategies to bypass the default pathway of phagosomal maturation to create a niche permissive for their survival and propagation. Here we discuss recent progress in our understanding of the sophisticated mechanisms used by Legionella pneumophila to survive in phagocytes.
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Affiliation(s)
- Li Xu
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, United States
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Orthopoxvirus genes that mediate disease virulence and host tropism. Adv Virol 2012; 2012:524743. [PMID: 22899927 PMCID: PMC3413996 DOI: 10.1155/2012/524743] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 05/31/2012] [Indexed: 12/16/2022] Open
Abstract
In the course of evolution, viruses have developed various molecular mechanisms to evade the defense reactions of the host organism. When understanding the mechanisms used by viruses to overcome manifold defense systems of the animal organism, represented by molecular factors and cells of the immune system, we would not only comprehend better but also discover new patterns of organization and function of these most important reactions directed against infectious agents. Here, study of the orthopoxviruses pathogenic for humans, such as variola (smallpox), monkeypox, cowpox, and vaccinia viruses, may be most important. Analysis of the experimental data, presented in this paper, allows to infer that variola virus and other orthopoxviruses possess an unexampled set of genes whose protein products efficiently modulate the manifold defense mechanisms of the host organisms compared with the viruses from other families.
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TolC-dependent secretion of an ankyrin repeat-containing protein of Rickettsia typhi. J Bacteriol 2012; 194:4920-32. [PMID: 22773786 DOI: 10.1128/jb.00793-12] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Rickettsia typhi, the causative agent of murine (endemic) typhus, is an obligate intracellular pathogen with a life cycle involving both vertebrate and invertebrate hosts. In this study, we characterized a gene (RT0218) encoding a C-terminal ankyrin repeat domain-containing protein, named Rickettsia ankyrin repeat protein 1 (RARP-1), and identified it as a secreted effector protein of R. typhi. RT0218 showed differential transcript abundance at various phases of R. typhi intracellular growth. RARP-1 was secreted by R. typhi into the host cytoplasm during in vitro infection of mammalian cells. Transcriptional analysis revealed that RT0218 was cotranscribed with adjacent genes RT0217 (hypothetical protein) and RT0216 (TolC) as a single polycistronic mRNA. Given one of its functions as a facilitator of extracellular protein secretion in some Gram-negative bacterial pathogens, we tested the possible role of TolC in the secretion of RARP-1. Using Escherichia coli C600 and an isogenic tolC insertion mutant as surrogate hosts, our data demonstrate that RARP-1 is secreted in a TolC-dependent manner. Deletion of either the N-terminal signal peptide or the C-terminal ankyrin repeats abolished RARP-1 secretion by wild-type E. coli. Importantly, expression of R. typhi tolC in the E. coli tolC mutant restored the secretion of RARP-1, suggesting that TolC has a role in RARP-1 translocation across the outer membrane. This work implies that the TolC component of the putative type 1 secretion system of R. typhi is involved in the secretion process of RARP-1.
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50
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Pilar AVC, Reid-Yu SA, Cooper CA, Mulder DT, Coombes BK. GogB is an anti-inflammatory effector that limits tissue damage during Salmonella infection through interaction with human FBXO22 and Skp1. PLoS Pathog 2012; 8:e1002773. [PMID: 22761574 PMCID: PMC3386239 DOI: 10.1371/journal.ppat.1002773] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 05/09/2012] [Indexed: 01/28/2023] Open
Abstract
Bacterial pathogens often manipulate host immune pathways to establish acute and chronic infection. Many Gram-negative bacteria do this by secreting effector proteins through a type III secretion system that alter the host response to the pathogen. In this study, we determined that the phage-encoded GogB effector protein in Salmonella targets the host SCF E3 type ubiquitin ligase through an interaction with Skp1 and the human F-box only 22 (FBXO22) protein. Domain mapping and functional knockdown studies indicated that GogB-containing bacteria inhibited IκB degradation and NFκB activation in macrophages, which required Skp1 and a eukaryotic-like F-box motif in the C-terminal domain of GogB. GogB-deficient Salmonella were unable to limit NFκB activation, which lead to increased proinflammatory responses in infected mice accompanied by extensive tissue damage and enhanced colonization in the gut during long-term chronic infections. We conclude that GogB is an anti-inflammatory effector that helps regulate inflammation-enhanced colonization by limiting tissue damage during infection. Bacterial pathogens have evolved sophisticated ways to subvert the innate defenses of their host. One way in which pathogens do so is by blocking or dampening the inflammatory response that is triggered once a microorganism is detected by the innate immune system. In this way, the microorganism can limit the activation of innate defenses in the host to promote its own colonization and dissemination. In this work we found that the enteric human pathogen Salmonella enterica serovar Typhimurium limits the activation of innate immune defenses in the host by using a bacterial protein called GogB to interfere with NFκB activation. NFκB is a key human transcription factor involved in the expression of pro-inflammatory cytokines during infection. In this infection situation, Salmonella delivers GogB to the infected cell where it interferes with ubiquitination of the NFκB inhibitor protein called IκBα to prevent translocation of NFκB to the nucleus where it would normally activate pro-inflammatory gene expression. The anti-inflammatory property of GogB is important for the bacteria to reach optimal infection densities in host tissues and to actively limit the tissue damage associated with prolonged inflammatory responses.
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Affiliation(s)
- Ana Victoria C. Pilar
- Michael G. DeGroote Institute for Infectious Disease Research and the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Sarah A. Reid-Yu
- Michael G. DeGroote Institute for Infectious Disease Research and the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Colin A. Cooper
- Michael G. DeGroote Institute for Infectious Disease Research and the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - David T. Mulder
- Michael G. DeGroote Institute for Infectious Disease Research and the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Brian K. Coombes
- Michael G. DeGroote Institute for Infectious Disease Research and the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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