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Timmerman AL, Schönert ALM, van der Hoek L. Anelloviruses versus human immunity: how do we control these viruses? FEMS Microbiol Rev 2024; 48:fuae005. [PMID: 38337179 PMCID: PMC10883694 DOI: 10.1093/femsre/fuae005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/22/2023] [Accepted: 02/08/2024] [Indexed: 02/12/2024] Open
Abstract
One continuous companion and one of the major players in the human blood virome are members of the Anelloviridae family. Anelloviruses are probably found in all humans, infection occurs early in life and the composition (anellome) is thought to remain stable and personal during adulthood. The stable anellome implies a great balance between the host immune system and the virus. However, the lack of a robust culturing system hampers direct investigation of interactions between virus and host cells. Other techniques, however, including next generation sequencing, AnelloScan-antibody tests, evolution selection pressure analysis, and virus protein structures, do provide new insights into the interactions between anelloviruses and the host immune system. This review aims at providing an overview of the current knowledge on the immune mechanisms acting on anelloviruses and the countering viral mechanisms allowing immune evasion.
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Affiliation(s)
- Anne L Timmerman
- Department of Medical Microbiology and Infection Prevention, Laboratory of Experimental Virology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
- Amsterdam institute for Infection and Immunity, Postbus 22660, 1100 DD, Amsterdam, the Netherlands
| | - Antonia L M Schönert
- Department of Medical Microbiology and Infection Prevention, Laboratory of Experimental Virology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
- Amsterdam institute for Infection and Immunity, Postbus 22660, 1100 DD, Amsterdam, the Netherlands
| | - Lia van der Hoek
- Department of Medical Microbiology and Infection Prevention, Laboratory of Experimental Virology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, the Netherlands
- Amsterdam institute for Infection and Immunity, Postbus 22660, 1100 DD, Amsterdam, the Netherlands
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Butkovic A, Kraberger S, Smeele Z, Martin DP, Schmidlin K, Fontenele RS, Shero MR, Beltran RS, Kirkham AL, Aleamotu’a M, Burns JM, Koonin EV, Varsani A, Krupovic M. Evolution of anelloviruses from a circovirus-like ancestor through gradual augmentation of the jelly-roll capsid protein. Virus Evol 2023; 9:vead035. [PMID: 37325085 PMCID: PMC10266747 DOI: 10.1093/ve/vead035] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 05/15/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
Anelloviruses are highly prevalent in diverse mammals, including humans, but so far have not been linked to any disease and are considered to be part of the 'healthy virome'. These viruses have small circular single-stranded DNA (ssDNA) genomes and encode several proteins with no detectable sequence similarity to proteins of other known viruses. Thus, anelloviruses are the only family of eukaryotic ssDNA viruses currently not included in the realm Monodnaviria. To gain insights into the provenance of these enigmatic viruses, we sequenced more than 250 complete genomes of anelloviruses from nasal and vaginal swab samples of Weddell seal (Leptonychotes weddellii) from Antarctica and a fecal sample of grizzly bear (Ursus arctos horribilis) from the USA and performed a comprehensive family-wide analysis of the signature anellovirus protein ORF1. Using state-of-the-art remote sequence similarity detection approaches and structural modeling with AlphaFold2, we show that ORF1 orthologs from all Anelloviridae genera adopt a jelly-roll fold typical of viral capsid proteins (CPs), establishing an evolutionary link to other eukaryotic ssDNA viruses, specifically, circoviruses. However, unlike CPs of other ssDNA viruses, ORF1 encoded by anelloviruses from different genera display remarkable variation in size, due to insertions into the jelly-roll domain. In particular, the insertion between β-strands H and I forms a projection domain predicted to face away from the capsid surface and function at the interface of virus-host interactions. Consistent with this prediction and supported by recent experimental evidence, the outermost region of the projection domain is a mutational hotspot, where rapid evolution was likely precipitated by the host immune system. Collectively, our findings further expand the known diversity of anelloviruses and explain how anellovirus ORF1 proteins likely diverged from canonical jelly-roll CPs through gradual augmentation of the projection domain. We suggest assigning Anelloviridae to a new phylum, 'Commensaviricota', and including it into the kingdom Shotokuvirae (realm Monodnaviria), alongside Cressdnaviricota and Cossaviricota.
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Affiliation(s)
- Anamarija Butkovic
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Archaeal Virology Unit, 25 rue du Dr Roux, Paris 75015, France
| | - Simona Kraberger
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, 1001 S. McAllister Ave, Tempe, AZ 85287, USA
| | - Zoe Smeele
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, 1001 S. McAllister Ave, Tempe, AZ 85287, USA
| | - Darren P Martin
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, 1001 S. McAllister Ave, Tempe, AZ 85287, USA
| | - Kara Schmidlin
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, 1001 S. McAllister Ave, Tempe, AZ 85287, USA
| | - Rafaela S Fontenele
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, 1001 S. McAllister Ave, Tempe, AZ 85287, USA
| | - Michelle R Shero
- Biology Department, Woods Hole Oceanographic Institution, 266 Woods Hole Rd, Woods Hole, MA 02543, USA
| | - Roxanne S Beltran
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, 130 McAllister Way, Santa Cruz, CA 95060, USA
| | - Amy L Kirkham
- U.S. Fish and Wildlife Service, Marine Mammals Management, 1011 E, Tudor Road, Anchorage, AK 99503, USA
| | - Maketalena Aleamotu’a
- School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia
| | - Jennifer M Burns
- Department of Biological Sciences, Texas Tech University, 2500 Broadway, Lubbock, TX 79409, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894, USA
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life Sciences, Arizona State University, 1001 S. McAllister Ave, Tempe, AZ 85287, USA
- Computational Biology Division, Department of Integrative Biomedical Sciences, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Observatory, 1 Anzio Road, Cape Town 7925, South Africa
| | - Mart Krupovic
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Archaeal Virology Unit, 25 rue du Dr Roux, Paris 75015, France
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3
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Taylo LJ, Keeler EL, Bushman FD, Collman RG. The enigmatic roles of Anelloviridae and Redondoviridae in humans. Curr Opin Virol 2022; 55:101248. [PMID: 35870315 DOI: 10.1016/j.coviro.2022.101248] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/06/2022] [Accepted: 06/09/2022] [Indexed: 12/26/2022]
Abstract
Anelloviridae and Redondoviridae are virus families with small, circular, single-stranded DNA genomes that are common components of the human virome. Despite their small genome size of less than 5000 bases, they are remarkably successful - anelloviruses colonize over 90% of adult humans, while the recently discovered redondoviruses have been found at up to 80% prevalence in some populations. Anelloviruses are present in blood and many organs, while redondoviruses are found mainly in the ororespiratory tract. Despite their high prevalence, little is known about their biology or pathogenic potential. In this review, we discuss anelloviruses and redondoviruses and explore their enigmatic roles in human health and disease.
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Affiliation(s)
- Louis J Taylo
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Emma L Keeler
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Frederic D Bushman
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ronald G Collman
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; Department of Medicine, Pulmonary, Allergy and Critical Care Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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4
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Feng C, Liang Y, Teodoro JG. The Role of Apoptin in Chicken Anemia Virus Replication. Pathogens 2020; 9:pathogens9040294. [PMID: 32316372 PMCID: PMC7238243 DOI: 10.3390/pathogens9040294] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/13/2020] [Accepted: 04/13/2020] [Indexed: 12/16/2022] Open
Abstract
Apoptin is the Vp3 protein of chicken anemia virus (CAV), which infects the thymocytes and erythroblasts in young chickens, causing chicken infectious anemia and immunosuppression. Apoptin is highly studied for its ability to selectively induce apoptosis in human tumor cells and, thus, is a protein of interest in anti-tumor therapy. CAV apoptin is known to localize to different subcellular compartments in transformed and non-transformed cells, depending on the DNA damage response, and the phosphorylation of several identified threonine residues. In addition, apoptin interacts with molecular machinery such as the anaphase promoting complex/cyclosome (APC/C) to inhibit the cell cycle and induce arrest in G2/M phase. While these functions of apoptin contribute to the tumor-selective effect of the protein, they also provide an important fundamental framework to apoptin’s role in viral infection, pathogenesis, and propagation. Here, we reviewed how the regulation, localization, and functions of apoptin contribute to the viral life cycle and postulated its importance in efficient replication of CAV. A model of the molecular biology of infection is critical to informing our understanding of CAV and other related animal viruses that threaten the agricultural industry.
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Affiliation(s)
- Cynthia Feng
- Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Yingke Liang
- Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Jose G. Teodoro
- Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada
- Goodman Cancer Research Centre, Montreal, QC H3G 1A1, Canada
- Correspondence:
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Yao S, Tuo T, Gao X, Han C, Yan N, Liu A, Gao H, Gao Y, Cui H, Liu C, Zhang Y, Qi X, Hussain A, Wang Y, Wang X. Molecular epidemiology of chicken anaemia virus in sick chickens in China from 2014 to 2015. PLoS One 2019; 14:e0210696. [PMID: 30657774 PMCID: PMC6338413 DOI: 10.1371/journal.pone.0210696] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 01/01/2019] [Indexed: 01/05/2023] Open
Abstract
Chicken anaemia virus (CAV), a member of the genus Gyrovirus, is the etiological agent of chicken infectious anaemia. CAV infects bone marrow-derived cells, resulting in severe anaemia and immunosuppression in young chickens and a compromised immune response in older birds. We investigated the molecular epidemiology of CAV in sick chickens in China from 2014 to 2015 and showed that the CAV-positive rate was 13.30%, in which mixed infection (55.56%) was the main type of infection. We isolated and identified 15 new CAV strains using different methods including indirect immunofluorescence assay and Western Blotting. We used overlapping polymerase chain reaction to map the whole genome of the strains. Phylogenetic analyses of the obtained sequences and related sequences available in GenBank generated four distinct groups (A-D). We built phylogenetic trees using predicted viral protein (VP) sequences. Unlike CAV VP2s and VP3s that were well conserved, the diversity of VP1s indicated that the new strains were virulent. Our epidemiological study provided new insights into the prevalence of CAV in clinical settings in recent years in China.
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Affiliation(s)
- Shuai Yao
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Tianbei Tuo
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiang Gao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Chunyan Han
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
- College of Wildlife Resource, Northeast Forestry University, Harbin, China
| | - Nana Yan
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Aijing Liu
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Honglei Gao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yulong Gao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Hongyu Cui
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Changjun Liu
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yanping Zhang
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiaole Qi
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Altaf Hussain
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Yongqiang Wang
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiaomei Wang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, China
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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6
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Curtis NL, Bolanos-Garcia VM. The Anaphase Promoting Complex/Cyclosome (APC/C): A Versatile E3 Ubiquitin Ligase. Subcell Biochem 2019; 93:539-623. [PMID: 31939164 DOI: 10.1007/978-3-030-28151-9_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
In the present chapter we discuss the essential roles of the human E3 ubiquitin ligase Anaphase Promoting Complex/Cyclosome (APC/C) in mitosis as well as the emerging evidence of important APC/C roles in cellular processes beyond cell division control such as regulation of genomic integrity and cell differentiation of the nervous system. We consider the potential incipient role of APC/C dysregulation in the pathophysiology of the neurological disorder Alzheimer's disease (AD). We also discuss how certain Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA) viruses take control of the host's cell division regulatory system through harnessing APC/C ubiquitin ligase activity and hypothesise the plausible molecular mechanisms underpinning virus manipulation of the APC/C. We also examine how defects in the function of this multisubunit protein assembly drive abnormal cell proliferation and lastly argue the potential of APC/C as a promising therapeutic target for the development of innovative therapies for the treatment of chronic malignancies such as cancer.
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Affiliation(s)
- Natalie L Curtis
- Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, England, UK
| | - Victor M Bolanos-Garcia
- Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, England, UK.
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Identification of the interaction and interaction domains of chicken anemia virus VP2 and VP3 proteins. Virology 2017; 513:188-194. [PMID: 29100148 DOI: 10.1016/j.virol.2017.09.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/11/2017] [Accepted: 09/17/2017] [Indexed: 01/18/2023]
Abstract
Chicken anemia virus (CAV) is a small, single-stranded DNA virus of Anelloviridae family. Its genome segments encode three proteins, VP1, VP2, and VP3. This study identified an interaction between VP2 and VP3 and mapped the interaction domains. Through the yeast two-hybrid (Y2H) system, VP2 was found to interact with VP3. The presence of the VP2-VP3 complex in CAV-infected chicken cells was confirmed by co-immunoprecipitation. Confocal microscopy showed that VP2 and VP3 were expressed in the cytoplasm in cotransfected Vero cells. In the Y2H system, the interaction domains were identified as being within the N-terminal aa 1-30 and C-terminal aa 17-60 for VP2 and the N-terminal aa 46-60 and C-terminal aa 1-7 for VP3. This study showed the interaction between VP2 and VP3 of CAV and identified multiple independent interactive domains within the two proteins. This provides novel information for investigating the biological functions of these proteins.
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Lai GH, Lien YY, Lin MK, Cheng JH, Tzen JT, Sun FC, Lee MS, Chen HJ, Lee MS. VP2 of Chicken Anaemia Virus Interacts with Apoptin for Down-regulation of Apoptosis through De-phosphorylated Threonine 108 on Apoptin. Sci Rep 2017; 7:14799. [PMID: 29093508 PMCID: PMC5665943 DOI: 10.1038/s41598-017-14558-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 10/11/2017] [Indexed: 12/18/2022] Open
Abstract
Chicken anaemia virus (CAV) is an important contagious agent that causes immunosuppressive disease in chickens. CAV Apoptin is a nucleoplasmic shuffling protein that induces apoptosis in chicken lymphoblastoid cells. In the present study, confocal microscopy revealed co-localisation of expressed CAV non-structural protein VP2 with Apoptin in the nucleus of MDCC-MSB1 cells and the nucleoplasmic compartment of CHO-K1 cells. In vitro pull-down and ex vivo biomolecular fluorescent complementation (BiFC) assays further showed that the VP2 protein directly interacts with Apoptin. Transient co-expression of VP2 and Apoptin in MDCC-MSB1 cells significantly decreased the rate of apoptosis compared with that in cells transfected with the Apoptin gene alone. In addition, the phosphorylation status of threonine 108 (Thr108) of Apoptin was found to decrease upon interaction with VP2. Although dephosphorylated Thr108 did not alter the subcellular distribution of Apoptin in the nucleus of MDCC-MSB1 cells, it did suppress apoptosis. These findings provide the first evidence that VP2 directly interacts with Apoptin in the nucleus to down-regulate apoptosis through alterations in the phosphorylation status of the latter. This information will be useful to further elucidate the underlying mechanism of viral replication in the CAV life cycle.
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Affiliation(s)
- Guan-Hua Lai
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40402, Taiwan
| | - Yi-Yang Lien
- Department of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, 91201, Taiwan
| | - Ming-Kuem Lin
- Department of Chinese Pharmaceutical Science and Chinese Medicine Resources, China Medical University, Taichung, 40402, Taiwan
| | - Jai-Hong Cheng
- Center for Shockwave Medicine and Tissue Engineering, Department of Medical Research, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, 83301, Taiwan
| | - Jason Tc Tzen
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40402, Taiwan
| | - Fang-Chun Sun
- Department of Bioresources, Da-Yeh University, Changhua, 515, Taiwan
| | - Meng-Shiunn Lee
- Research Assistance Center, Show Chwan Memorial Hospital, Changhua, 500, Taiwan
| | - Hsi-Jien Chen
- Department of Safety, Health and Environmental Engineering, Ming Chi University of Technology, New Taipei, 24301, Taiwan
| | - Meng-Shiou Lee
- Department of Chinese Pharmaceutical Science and Chinese Medicine Resources, China Medical University, Taichung, 40402, Taiwan.
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Abstract
Circular single-stranded DNA viruses infect archaea, bacteria, and eukaryotic organisms. The relatively recent emergence of single-stranded DNA viruses, such as chicken anemia virus (CAV) and porcine circovirus 2 (PCV2), as serious pathogens of eukaryotes is due more to growing awareness than to the appearance of new pathogens or alteration of existing pathogens. In the case of the ubiquitous human circular single-stranded DNA virus family Anelloviridae, there is still no convincing direct causal relation to any specific disease. However, infections may play a role in autoimmunity by changing the homeostatic balance of proinflammatory cytokines and the human immune system, indirectly affecting the severity of diseases caused by other pathogens. Infections with CAV (family Anelloviridae, genus Gyrovirus) and PCV2 (family Circoviridae, genus Circovirus) are presented here because they are immunosuppressive and affect health in domesticated animals. CAV shares genomic organization, genomic orientation, and common features of major proteins with human anelloviruses, and PCV2 DNA may be present in human food and vaccines.
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Affiliation(s)
- L M Shulman
- Department of Epidemiology and Preventive Medicine, School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel; .,Laboratory of Environmental Virology, Central Virology Laboratory, Sheba Medical Center Public Health Services, Israel Ministry of Health, Tel Hashomer, 52621, Israel
| | - I Davidson
- Division of Avian Diseases, Kimron Veterinary Institute, Bet Dagan, 50250, Israel;
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Zhang Z, Dai W, Dai D. Molecular characterization of pigeon torque teno virus (PTTV) in Jiangsu province. Comput Biol Chem 2017; 69:10-18. [PMID: 28527409 DOI: 10.1016/j.compbiolchem.2017.04.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/08/2017] [Accepted: 04/13/2017] [Indexed: 10/19/2022]
Abstract
The torque teno virus (TTV) is a recently discovered DNA virus that has been detected in many different hosts, including humans, livestock and poultry. To date, there is no report of pigeon TTV (PTTV) from anywhere in the world. To investigate the distribution of PTTV in pigeons from the eastern Chinese province of Jiangsu and characterize their genomes, we employed PCR to detect PTTV in 144 samples collected from 6 pigeon plants in Jiangsu province, amplify complete genomes from representative samples and analyze genetic characteristics using bioinformatics. The results demonstrated that 71.5% (103/144) of samples were PTTV positive. The rate of sequence homology among the six PTTV complete genomes obtained from Jiangsu province ranged from 99.7% to 100%. Phylogenetic analysis suggested that PTTV genomes had a high degree of genetic similarity and were similar to chicken anemia virus that also had poultry as a host. Although with the same host, PTTV shared distant relationship with PiCV in both complete genome, Rep and Cap genes. The results of this study provided evidence that PTTV could be detected in Chinese pigeons at a high level, the evolutionary process of complete genome, Rep and Cap genes of Anelloviridae family had obvious divergence.
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Affiliation(s)
- Zhicheng Zhang
- Department of Animal Science and Technology, Jinling Institute of Technology, Nanjing, China.
| | - Wei Dai
- The State Key Laboratory of Bioelectronics, Southeast University, Nanjing, China
| | - Dingzhen Dai
- Department of Animal Science and Technology, Jinling Institute of Technology, Nanjing, China
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11
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Wang Y, Song X, Gao H, Wang X, Hu Y, Gao Y, Qi X, Qin L, Lin H, Gao L, Yao S, Han C, Wang X, Chen H. C-terminal region of apoptin affects chicken anemia virus replication and virulence. Virol J 2017; 14:38. [PMID: 28222746 PMCID: PMC5320637 DOI: 10.1186/s12985-017-0713-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 02/17/2017] [Indexed: 11/25/2022] Open
Abstract
Background Chicken anemia virus (CAV) causes anemia and immune suppression, which are important diseases in the poultry industry. CAV VP3, also referred as ‘apoptin’, has been shown to selectively kill tumor cells, raising great hopes for its utilization as an anticancer therapy. The ability of apoptin to induce apoptosis is closely related to its nuclear localization. The C-terminal region of apoptin contains a bipartite nuclear localization signals (NLS), and a nuclear export signal (NES) is located between the arms of the NLS. Most previous studies have expressed apoptin of different lengths in vitro to understand the relationship between its localization and its induction of apoptosis. Methods In this study, we investigated the replication of CAV and its induction of apoptosis in vitro and in vivo with VP3-truncated infectious virus. Quantitative PCR was used to detect viral replication in MDCC-MSB1 cells, and the viral localization was observed by confocal microscopy. Flow cytometry was uesed to analyze virus-induced apoptosis in MDCC-MSB1 cells. Additionally, chickens infected with the rescued viruses compared with the parental virus rM9905 to evaluate the viral replication in vivo and virulence. Results Based on the infectious clone, we rescued two viruses in which were deleted NES–NLS2 (rCAV-VP3N88) or NLS1–NES–NLS2 (rCAV-VP3N80) in the C-terminal region of apoptin. The viral load of rCAV-VP3N88 decreased significantly between 60 and 108 hpi, and was always 10–100-fold lower than that of the parental virus rM9905. The levels of rCAV-VP3N80 were also 10–100-fold lower than that of rM9905 and declined significantly at three time points. There was almost no difference in the viral loads of rCAV-VP3N88 and rCAV-VP3N80. Additionally, rM9905 induced 85.39 ± 2.18% apoptosis at 96 hpi, whereas rCAV-VP3N88 and rCAV-VP3N80 induced 63.08 ± 4.78% and 62.56 ± 7.35% apoptosis, respectively, which were significantly (about 20%) lower than that induced by the parental virus. The rescued viruses altered the nuclear localization in MDCC-MSB1 cells. Moreover, deletion of C-terminal region of apoptin impaired viral replication in vivo and reduced the virulence of CAV in chickens. Conclusions In summary, we have demonstrated that the C-terminal deletion of apoptin in infectious CAV affected the replication of the virus. The deletion of the C-terminal region of apoptin not only significantly reduced viral replication in vitro but also reduced its induction of apoptosis, which correlated with the loss of its nuclear localization. The deletion of the C-terminal region of apoptin also impaired the replication of CAV and attenuated its virulence in chickens.
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Affiliation(s)
- Yongqiang Wang
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, People's Republic of China.,State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Xiuqing Song
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Honglei Gao
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Xiaoyan Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Yonghao Hu
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, People's Republic of China
| | - Yulong Gao
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Xiaole Qi
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Liting Qin
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Huan Lin
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Li Gao
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Shuai Yao
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Chunyan Han
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Xiaomei Wang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Hualan Chen
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, People's Republic of China. .,State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
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Rosario K, Breitbart M, Harrach B, Segalés J, Delwart E, Biagini P, Varsani A. Revisiting the taxonomy of the family Circoviridae: establishment of the genus Cyclovirus and removal of the genus Gyrovirus. Arch Virol 2017; 162:1447-1463. [PMID: 28155197 DOI: 10.1007/s00705-017-3247-y] [Citation(s) in RCA: 240] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 12/29/2016] [Indexed: 12/19/2022]
Abstract
The family Circoviridae contains viruses with covalently closed, circular, single-stranded DNA (ssDNA) genomes, including the smallest known autonomously replicating, capsid-encoding animal pathogens. Members of this family are known to cause fatal diseases in birds and pigs and have been historically classified in one of two genera: Circovirus, which contains avian and porcine pathogens, and Gyrovirus, which includes a single species (Chicken anemia virus). However, over the course of the past six years, viral metagenomic approaches as well as degenerate PCR detection in unconventional hosts and environmental samples have elucidated a broader host range, including fish, a diversity of mammals, and invertebrates, for members of the family Circoviridae. Notably, these methods have uncovered a distinct group of viruses that are closely related to members of the genus Circovirus and comprise a new genus, Cyclovirus. The discovery of new viruses and a re-evaluation of genomic features that characterize members of the Circoviridae prompted a revision of the classification criteria used for this family of animal viruses. Here we provide details on an updated Circoviridae taxonomy ratified by the International Committee on the Taxonomy of Viruses in 2016, which establishes the genus Cyclovirus and reassigns the genus Gyrovirus to the family Anelloviridae, a separate lineage of animal viruses that also contains circular ssDNA genomes. In addition, we provide a new species demarcation threshold of 80% genome-wide pairwise identity for members of the family Circoviridae, based on pairwise identity distribution analysis, and list guidelines to distinguish between members of this family and other eukaryotic viruses with circular, ssDNA genomes.
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Affiliation(s)
- Karyna Rosario
- College of Marine Science, University of South Florida, Saint Petersburg, FL, 33701, USA.
| | - Mya Breitbart
- College of Marine Science, University of South Florida, Saint Petersburg, FL, 33701, USA
| | - Balázs Harrach
- Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary
| | - Joaquim Segalés
- Departament de Sanitat i Anatomia Animals, Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
- UAB, Centre de Recerca en Sanitat Animal (CReSA, IRTA-UAB), Campus de la Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - Eric Delwart
- Blood Systems Research Institute, San Francisco, California, USA
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Philippe Biagini
- Viral Emergence and Co-evolution Unit, ADES, UMR 7268, Aix-Marseille University, CNRS, EFS, 27 Bd. Jean Moulin, 13005, Marseille, France
| | - Arvind Varsani
- The Biodesign Center for Fundamental and Applied Microbiomics, Center for Evolution and Medicine, School of Life sciences, Arizona State University, Tempe, AZ, 85287-5001, USA.
- Structural Biology Research Unit, Department of Clinical Laboratory Sciences, University of Cape Town, Observatory, Cape Town, South Africa.
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13
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A truncated apoptin protein variant selectively kills cancer cells. Invest New Drugs 2017; 35:260-268. [DOI: 10.1007/s10637-017-0431-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/16/2017] [Indexed: 12/21/2022]
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Activation of the Chicken Anemia Virus Apoptin Protein by Chk1/2 Phosphorylation Is Required for Apoptotic Activity and Efficient Viral Replication. J Virol 2016; 90:9433-45. [PMID: 27512067 DOI: 10.1128/jvi.00936-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 08/03/2016] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Chicken anemia virus (CAV) is a single-stranded circular DNA virus that carries 3 genes, the most studied of which is the gene encoding VP3, also known as apoptin. This protein has been demonstrated to specifically kill transformed cells while leaving normal cells unharmed in a manner that is independent of p53 status. Although the mechanistic basis for this differential activity is unclear, it is evident that the subcellular localization of the protein is important for the difference. In normal cells, apoptin exists in filamentous networks in the cytoplasm, whereas in transformed cells, apoptin is present in the nucleus and appears as distinct foci. We have previously demonstrated that DNA damage signaling through the ataxia telangiectasia mutated (ATM) pathway induces the translocation of apoptin from the cytoplasm to the nucleus, where it induces apoptosis. We found that apoptin contains four checkpoint kinase consensus sites and that mutation of either threonine 56 or 61 to alanine restricts apoptin to the cytoplasm. Furthermore, treatment of tumor cells expressing apoptin with inhibitors of checkpoint kinase 1 (Chk1) and Chk2 causes apoptin to localize to the cytoplasm. Importantly, silencing of Chk2 rescues cancer cells from the cytotoxic effects of apoptin. Finally, treatment of virus-producing cells with Chk inhibitor protects them from virus-mediated toxicity and reduces the titer of progeny virus. Taken together, our results indicate that apoptin is a sensor of DNA damage signaling through the ATM-Chk2 pathway, which induces it to migrate to the nucleus during viral replication. IMPORTANCE The chicken anemia virus (CAV) protein apoptin is known to induce tumor cell-specific death when expressed. Therefore, understanding its regulation and mechanism of action could provide new insights into tumor cell biology. We have determined that checkpoint kinase 1 and 2 signaling is important for apoptin regulation and is a likely feature of both tumor cells and host cells producing virus progeny. Inhibition of checkpoint signaling prevents apoptin toxicity in tumor cells and attenuates CAV replication, suggesting it may be a future target for antiviral therapy.
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Caly L, Ghildyal R, Jans DA. Respiratory virus modulation of host nucleocytoplasmic transport; target for therapeutic intervention? Front Microbiol 2015; 6:848. [PMID: 26322040 PMCID: PMC4536372 DOI: 10.3389/fmicb.2015.00848] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/03/2015] [Indexed: 01/02/2023] Open
Abstract
The respiratory diseases caused by rhinovirus, respiratory syncytial virus, and influenza virus represent a large social and financial burden on healthcare worldwide. Although all three viruses have distinctly unique properties in terms of infection and replication, they share the ability to exploit/manipulate the host-cell nucleocytoplasmic transport system in order to replicate effectively and efficiently. This review outlines the various ways in which infection by these viruses impacts on the host nucleocytoplasmic transport system, and examples where inhibition thereof in turn decreases viral replication. The highly conserved nature of the nucleocytoplasmic transport system and the viral proteins that interact with it make this virus–host interface a prime candidate for the development of specific antiviral therapeutics in the future.
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Affiliation(s)
- Leon Caly
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC Australia
| | - Reena Ghildyal
- Faculty of ESTeM, University of Canberra, Bruce, ACT Australia
| | - David A Jans
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC Australia
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16
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Giotis ES, Rothwell L, Scott A, Hu T, Talbot R, Todd D, Burt DW, Glass EJ, Kaiser P. Transcriptomic Profiling of Virus-Host Cell Interactions following Chicken Anaemia Virus (CAV) Infection in an In Vivo Model. PLoS One 2015; 10:e0134866. [PMID: 26244502 PMCID: PMC4526643 DOI: 10.1371/journal.pone.0134866] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 07/14/2015] [Indexed: 12/18/2022] Open
Abstract
Chicken Anaemia Virus (CAV) is an economically important virus that targets lymphoid and erythroblastoid progenitor cells leading to immunosuppression. This study aimed to investigate the interplay between viral infection and the host's immune response to better understand the pathways that lead to CAV-induced immunosuppression. To mimic vertical transmission of CAV in the absence of maternally-derived antibody, day-old chicks were infected and their responses measured at various time-points post-infection by qRT-PCR and gene expression microarrays. The kinetics of mRNA expression levels of signature cytokines of innate and adaptive immune responses were determined by qRT-PCR. The global gene expression profiles of mock-infected (control) and CAV-infected chickens at 14 dpi were also compared using a chicken immune-related 5K microarray. Although in the thymus there was evidence of induction of an innate immune response following CAV infection, this was limited in magnitude. There was little evidence of a Th1 adaptive immune response in any lymphoid tissue, as would normally be expected in response to viral infection. Most cytokines associated with Th1, Th2 or Treg subsets were down-regulated, except IL-2, IL-13, IL-10 and IFNγ, which were all up-regulated in thymus and bone marrow. From the microarray studies, genes that exhibited significant (greater than 1.5-fold, false discovery rate <0.05) changes in expression in thymus and bone marrow on CAV infection were mainly associated with T-cell receptor signalling, immune response, transcriptional regulation, intracellular signalling and regulation of apoptosis. Expression levels of a number of adaptor proteins, such as src-like adaptor protein (SLA), a negative regulator of T-cell receptor signalling and the transcription factor Special AT-rich Binding Protein 1 (SATB1), were significantly down-regulated by CAV infection, suggesting potential roles for these genes as regulators of viral infection or cell defence. These results extend our understanding of CAV-induced immunosuppression and suggest a global immune dysregulation following CAV infection.
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Affiliation(s)
- Efstathios S. Giotis
- Agri-Food and Biosciences Institute, Belfast, United Kingdom
- Queen’s University Belfast, Belfast, United Kingdom
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - Lisa Rothwell
- Institute for Animal Health, Compton, United Kingdom
| | | | - Tuanjun Hu
- Institute for Animal Health, Compton, United Kingdom
| | - Richard Talbot
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - Daniel Todd
- Agri-Food and Biosciences Institute, Belfast, United Kingdom
| | - David W. Burt
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - Elizabeth J. Glass
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - Pete Kaiser
- Institute for Animal Health, Compton, United Kingdom
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Rollano Peñaloza OM, Lewandowska M, Stetefeld J, Ossysek K, Madej M, Bereta J, Sobczak M, Shojaei S, Ghavami S, Łos MJ. Apoptins: selective anticancer agents. Trends Mol Med 2014; 20:519-28. [PMID: 25164066 DOI: 10.1016/j.molmed.2014.07.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 07/17/2014] [Accepted: 07/17/2014] [Indexed: 12/20/2022]
Abstract
Therapies that selectively target cancer cells for death have been the center of intense research recently. One potential therapy may involve apoptin proteins, which are able to induce apoptosis in cancer cells leaving normal cells unharmed. Apoptin was originally discovered in the Chicken anemia virus (CAV); however, human gyroviruses (HGyV) have recently been found that also harbor apoptin-like proteins. Although the cancer cell specific activity of these apoptins appears to be well conserved, the precise functions and mechanisms of action are yet to be fully elucidated. Strategies for both delivering apoptin to treat tumors and disseminating the protein inside the tumor body are now being developed, and have shown promise in preclinical animal studies.
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Affiliation(s)
- Oscar M Rollano Peñaloza
- Department Clinical & Experimental Medicine, Division of Cell Biology, and Integrative Regenerative Medical Center, Linköping University, Linköping, Sweden; Instituto de Biologia Molecular y Biotecnologia, La Paz, Bolivia
| | | | - Joerg Stetefeld
- Department of Chemistry, University of Manitoba, Winnipeg, Canada
| | - Karolina Ossysek
- Department of Cell Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Mariusz Madej
- Department of Cell Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Joanna Bereta
- Department of Cell Biochemistry, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Mateusz Sobczak
- Department of Medical Biotechnology, Faculty of Biochemistry Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Shahla Shojaei
- Department of Biochemistry, Recombinant Protein Laboratory, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Saeid Ghavami
- Department of Human Anatomy & Cell Science, College of Medicine, Faculty of Health Sciences, and Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Canada; Health Policy Research Centre, Shiraz University of Medical Science, Shiraz, Iran
| | - Marek J Łos
- Department Clinical & Experimental Medicine, Division of Cell Biology, and Integrative Regenerative Medical Center, Linköping University, Linköping, Sweden; Department of Pathology, Pomeranian Medical University, Szczecin, Poland.
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18
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Abstract
Viruses commonly manipulate cell cycle progression to create cellular conditions that are most beneficial to their replication. To accomplish this feat, viruses often target critical cell cycle regulators in order to have maximal effect with minimal input. One such master regulator is the large, multisubunit E3 ubiquitin ligase anaphase-promoting complex (APC) that targets effector proteins for ubiquitination and proteasome degradation. The APC is essential for cells to progress through anaphase, exit from mitosis, and prevent a premature entry into S phase. These far-reaching effects of the APC on the cell cycle are through its ability to target a number of substrates, including securin, cyclin A, cyclin B, thymidine kinase, geminin, and many others. Recent studies have identified several proteins from a number of viruses that can modulate APC activity by different mechanisms, highlighting the potential of the APC in driving viral replication or pathogenesis. Most notably, human cytomegalovirus (HCMV) protein pUL21a was recently identified to disable the APC via a novel mechanism by targeting APC subunits for degradation, both during virus infection and in isolation. Importantly, HCMV lacking both viral APC regulators is significantly attenuated, demonstrating the impact of the APC on a virus infection. Work in this field will likely lead to novel insights into viral replication and pathogenesis and APC function and identify novel antiviral and anticancer targets. Here we review viral mechanisms to regulate the APC, speculate on their roles during infection, and identify questions to be addressed in future studies.
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Proteasome-dependent disruption of the E3 ubiquitin ligase anaphase-promoting complex by HCMV protein pUL21a. PLoS Pathog 2012; 8:e1002789. [PMID: 22792066 PMCID: PMC3390409 DOI: 10.1371/journal.ppat.1002789] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 05/22/2012] [Indexed: 01/27/2023] Open
Abstract
The anaphase-promoting complex (APC) is an E3 ubiquitin ligase which controls ubiquitination and degradation of multiple cell cycle regulatory proteins. During infection, human cytomegalovirus (HCMV), a widespread pathogen, not only phosphorylates the APC coactivator Cdh1 via the multifunctional viral kinase pUL97, it also promotes degradation of APC subunits via an unknown mechanism. Using a proteomics approach, we found that a recently identified HCMV protein, pUL21a, interacted with the APC. Importantly, we determined that expression of pUL21a was necessary and sufficient for proteasome-dependent degradation of APC subunits APC4 and APC5. This resulted in APC disruption and required pUL21a binding to the APC. We have identified the proline-arginine amino acid pair at residues 109–110 in pUL21a to be critical for its ability to bind and regulate the APC. A point mutant virus in which proline-arginine were mutated to alanines (PR-AA) grew at wild-type levels. However, a double mutant virus in which the viral ability to regulate the APC was abrogated by both PR-AA point mutation and UL97 deletion was markedly more attenuated compared to the UL97 deletion virus alone. This suggests that these mutations are synthetically lethal, and that HCMV exploits two viral factors to ensure successful disruption of the APC to overcome its restriction on virus infection. This study reveals the HCMV protein pUL21a as a novel APC regulator and uncovers a unique viral mechanism to subvert APC activity. In this study, we report an intriguing mechanism used by human cytomegalovirus (HCMV) to regulate a cellular E3 ubiquitin ligase, the anaphase promoting complex (APC). The ability to hijack the ubiquitin-proteasome system for regulating protein degradation and to manipulate the cell cycle for viral genome synthesis is critical in many viral infections. The APC is a master cell cycle modulator that targets a number of regulatory proteins for proteasomal degradation. It can prevent cells from entry into S-phase, thus creating a hindrance for viruses needing to coerce cells into a cellular environment favorable for viral DNA synthesis. We have identified an HCMV protein, pUL21a, which uses a seemingly counterintuitive mechanism to regulate the APC. It interacts with the APC to target the subunits of this ubiquitin ligase for proteasomal degradation. This causes disruption of the complex and reduces its activity. Furthermore, a virus lacking pUL21a and pUL97, which is another HCMV-encoded APC regulator, was highly attenuated when compared to loss of UL97 alone, suggesting that HCMV uses two proteins to fully disarm the APC. This study identifies a herpesviral protein that uses a unique, proteasome-dependent mechanism to regulate the activity of this prominent cellular E3 ubiquitin ligase.
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A field guide to eukaryotic circular single-stranded DNA viruses: insights gained from metagenomics. Arch Virol 2012; 157:1851-71. [DOI: 10.1007/s00705-012-1391-y] [Citation(s) in RCA: 187] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 05/16/2012] [Indexed: 10/28/2022]
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21
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Mo M, Shahar S, Fleming SB, Mercer AA. How viruses affect the cell cycle through manipulation of the APC/C. Trends Microbiol 2012; 20:440-8. [PMID: 22727131 DOI: 10.1016/j.tim.2012.05.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 05/21/2012] [Accepted: 05/28/2012] [Indexed: 02/06/2023]
Abstract
Viruses frequently exploit host cell cycle machineries for their own benefit, often by targeting 'master switches' of cell cycle regulation. By doing so, they achieve maximum effect from minimal input. One such master switch is the anaphase promoting complex or cyclosome (APC/C), a multicomponent ubiquitin ligase and a dominant regulator of the cell cycle. A growing number of viruses have been shown to target the APC/C. Although differing strategies are employed, viral manipulation of the APC/C seems to serve a common purpose, namely, to create an environment supportive of viral replication. Here, the molecular mechanisms employed by these viruses are summarized and discussed.
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Affiliation(s)
- Min Mo
- Department of Microbiology and Immunology, University of Otago, PO Box 56, Dunedin 9016, New Zealand
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Regulation of nucleocytoplasmic trafficking of viral proteins: an integral role in pathogenesis? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:2176-90. [PMID: 21530593 PMCID: PMC7114211 DOI: 10.1016/j.bbamcr.2011.03.019] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 03/15/2011] [Accepted: 03/30/2011] [Indexed: 12/24/2022]
Abstract
Signal-dependent targeting of proteins into and out of the nucleus is mediated by members of the importin (IMP) family of transport receptors, which recognise targeting signals within a cargo protein and mediate passage through the nuclear envelope-embedded nuclear pore complexes. Regulation of this process is paramount to processes such as cell division and differentiation, but is also critically important for viral replication and pathogenesis; phosphorylation appears to play a major role in regulating viral protein nucleocytoplasmic trafficking, along with other posttranslational modifications. This review focuses on viral proteins that utilise the host cell IMP machinery in order to traffic into/out of the nucleus, and in particular those where trafficking is critical to viral replication and/or pathogenesis, such as simian virus SV40 large tumour antigen (T-ag), human papilloma virus E1 protein, human cytomegalovirus processivity factor ppUL44, and various gene products from RNA viruses such as Rabies. Understanding of the mechanisms regulating viral protein nucleocytoplasmic trafficking is paramount to the future development of urgently needed specific and effective anti-viral therapeutics. This article was originally intended for the special issue "Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import". The Publisher apologizes for any inconvenience caused.
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Huang YW, Ni YY, Dryman BA, Meng XJ. Multiple infection of porcine Torque teno virus in a single pig and characterization of the full-length genomic sequences of four U.S. prototype PTTV strains: implication for genotyping of PTTV. Virology 2009; 396:289-97. [PMID: 19913866 DOI: 10.1016/j.virol.2009.10.031] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 09/23/2009] [Accepted: 10/19/2009] [Indexed: 11/17/2022]
Abstract
Porcine Torque teno virus (PTTV) was recently shown to partially contribute to the experimental induction of porcine dermatitis and nephropathy syndrome and postweaning multisystemic wasting syndrome in pigs in the United States. We report here the identification of four distinct full-length genomic sequences of PTTV strains from a single pig in Virginia. Detailed analyses of the genomic organization, the degree of variability and the characteristics of conserved nucleotide and amino acid motifs of PTTV were conducted. The results showed that these four prototype U.S. strains of PTTV identified from the same pig represent distinct genotypes or subtypes and a revised classification system for PPTV is subsequently proposed. This is the first study documenting multiple PTTV infections with distinct genotypes or subtypes in a single pig. The identification of novel PTTV strains from pigs in the United States also pave the way for future disease characterization and genotyping of PTTV.
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Affiliation(s)
- Y W Huang
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, 1981 Kraft Drive, Blacksburg, VA 24061-0913, USA
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