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Jarosz AS, Halo JV. Transcription of Endogenous Retroviruses: Broad and Precise Mechanisms of Control. Viruses 2024; 16:1312. [PMID: 39205286 PMCID: PMC11359688 DOI: 10.3390/v16081312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Revised: 08/07/2024] [Accepted: 08/16/2024] [Indexed: 09/04/2024] Open
Abstract
Endogenous retroviruses (ERVs) are the remnants of retroviral germline infections and are highly abundant in the genomes of vertebrates. At one time considered to be nothing more than inert 'junk' within genomes, ERVs have been tolerated within host genomes over vast timescales, and their study continues to reveal complex co-evolutionary histories within their respective host species. For example, multiple instances have been characterized of ERVs having been 'borrowed' for normal physiology, from single copies to ones involved in various regulatory networks such as innate immunity and during early development. Within the cell, the accessibility of ERVs is normally tightly controlled by epigenetic mechanisms such as DNA methylation or histone modifications. However, these silencing mechanisms of ERVs are reversible, and epigenetic alterations to the chromatin landscape can thus lead to their aberrant expression, as is observed in abnormal cellular environments such as in tumors. In this review, we focus on ERV transcriptional control and draw parallels and distinctions concerning the loss of regulation in disease, as well as their precise regulation in early development.
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Affiliation(s)
- Abigail S. Jarosz
- Science and Mathematics Division, Lorrain County Community College, Lorrain, OH 44035, USA;
| | - Julia V. Halo
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA
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Hemida MG, Alnaeem AA. Betaretrovirus infections in dromedary camels in Saudi Arabia. Vet Med Sci 2022; 8:1330-1336. [PMID: 35114072 PMCID: PMC9122393 DOI: 10.1002/vms3.760] [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] [Indexed: 12/03/2022] Open
Abstract
Background Retroviral infections have been reported in many species of animals, especially cattle, sheep and goats. However, there are no available reports about retrovirus infection in dromedary camels. Several dromedary camels showed visible tumor‐like lesions on and around the nostrils as well as around the eyes. Objectives Following are the objectives: to identify the causative agents of these identified tumours in dromedary camels and to perform molecular characterization of the detected strains of the causative agent. Methods We extracted the nucleic acids from some fresh lesions out of these animals, and then amplified some key retrovirus genes. We amplified several regions of the rotavirus genome using the PCR technique. The obtained sequences were assembled and the phylogenetic trees were conducted per each target retrovirus gene. Results Our results revealed a high degree of identity to some retroviruses of sheep. Phylogenetic analysis based on some retrovirus genes revealed that the causative agents of these lesions are closely related to sheep retroviruses, particularly the Jaagsiekte sheep Retrovirus (JSRV) and the ENTV. Conclusions To the best of our knowledge, this is the first report of retrovirus infections in dromedary camels in the Arabian Peninsula. This highlights the possible species jump for the retrovirus from sheep and goats to the dromedary camels, which live in close proximity with these animals in many parts of the world, especially the Arabian Peninsula. Our findings show for the first time the detection, identification and molecular characterization of retrovirus infection in dromedary camels in Saudi Arabia. We detected betaretrovirus infections in skin lesions in the head and around the nostrils and eyes of some dromedary camels. Our findings clearly demonstrate the causative agent for these lesions belongs to the betaretrovirus. The reported sequences out of these lesions showed a high degree of similarity to some sheep retroviruses, especially the Jaagsiekte sheep Retrovirus (JSRV). This study suggests that the potential interspecies transmission of retroviruses from sheep to dromedary camels live in close proximity of each other.
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Affiliation(s)
- Maged Gomaa Hemida
- Department of Microbiology, College of Veterinary Medicine, King Faisal University, Al Ahsa, Saudi Arabia.,Department of Virology, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafrelsheikh, Egypt
| | - Abdelmohsen A Alnaeem
- Department of Clinical Studies, College of Veterinary Medicine, King Faisal University, Al Ahsa, Saudi Arabia
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Ryser-Degiorgis MP, Marti I, Pisano SRR, Pewsner M, Wehrle M, Breitenmoser-Würsten C, Origgi FC, Kübber-Heiss A, Knauer F, Posautz A, Eberspächer-Schweda M, Huder JB, Böni J, Kubacki J, Bachofen C, Riond B, Hofmann-Lehmann R, Meli ML. Management of Suspected Cases of Feline Immunodeficiency Virus Infection in Eurasian Lynx ( Lynx lynx) During an International Translocation Program. Front Vet Sci 2021; 8:730874. [PMID: 34760956 PMCID: PMC8573149 DOI: 10.3389/fvets.2021.730874] [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: 06/25/2021] [Accepted: 09/10/2021] [Indexed: 11/22/2022] Open
Abstract
The Eurasian lynx (Lynx lynx) population in Switzerland serves as a source for reintroductions in neighboring countries. In 2016–2017, three lynx from the same geographical area were found seropositive for feline immunodeficiency virus (FIV) in the framework of an international translocation program. This novel finding raised questions about the virus origin and pathogenicity to lynx, the emerging character of the infection, and the interpretation of serological results in other lynx caught for translocation. Archived serum samples from 84 lynx captured in 2001–2016 were retrospectively tested for FIV antibodies by Western blot. All archived samples were FIV-negative. The three seropositive lynx were monitored in quarantine enclosures prior to euthanasia and necropsy. They showed disease signs, pathological findings, and occurrence of co-infections reminding of those described in FIV-infected domestic cats. All attempts to isolate and characterize the virus failed but serological data and spatiotemporal proximity of the cases suggested emergence of a lentivirus with antigenic and pathogenic similarities to FIV in the Swiss lynx population. A decision scheme was developed to minimize potential health risks posed by FIV infection, both in the recipient and source lynx populations, considering conservation goals, animal welfare, and the limited action range resulting from local human conflicts. Development and implementation of a cautious decision scheme was particularly challenging because FIV pathogenic potential in lynx was unclear, negative FIV serological results obtained within the first weeks after infection are unpredictable, and neither euthanasia nor repatriation of multiple lynx was acceptable options. The proposed scheme distinguished between three scenarios: release at the capture site, translocation, or euthanasia. Until April 2021, none of the 40 lynx newly captured in Switzerland tested FIV-seropositive. Altogether, seropositivity to FIV was documented in none of 124 lynx tested at their first capture, but three of them seroconverted in 2016–2017. Diagnosis of FIV infection in the three seropositive lynx remains uncertain, but clinical observations and pathological findings confirmed that euthanasia was appropriate. Our experiences underline the necessity to include FIV in pathogen screenings of free-ranging European wild felids, the importance of lynx health monitoring, and the usefulness of health protocols in wildlife translocation.
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Affiliation(s)
| | - Iris Marti
- Institute for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Simone R R Pisano
- Institute for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Mirjam Pewsner
- Institute for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | | | | | - Francesco C Origgi
- Institute for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Anna Kübber-Heiss
- Research Institute of Wildlife Ecology, University of Vienna, Vienna, Austria
| | - Felix Knauer
- Research Institute of Wildlife Ecology, University of Vienna, Vienna, Austria
| | - Annika Posautz
- Research Institute of Wildlife Ecology, University of Vienna, Vienna, Austria
| | - Matthias Eberspächer-Schweda
- Dentistry and Oral Surgery Service, Department/Hospital for Companion Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Jon B Huder
- Swiss National Center for Retroviruses, Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Jürg Böni
- Swiss National Center for Retroviruses, Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Jakub Kubacki
- Institute of Virology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Claudia Bachofen
- Institute of Virology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Barbara Riond
- Clinical Laboratory, Department of Clinical Diagnostics and Services, and Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Regina Hofmann-Lehmann
- Clinical Laboratory, Department of Clinical Diagnostics and Services, and Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
| | - Marina L Meli
- Clinical Laboratory, Department of Clinical Diagnostics and Services, and Center for Clinical Studies, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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Marawan MA, Alouffi A, El Tokhy S, Badawy S, Shirani I, Dawood A, Guo A, Almutairi MM, Alshammari FA, Selim A. Bovine Leukaemia Virus: Current Epidemiological Circumstance and Future Prospective. Viruses 2021; 13:v13112167. [PMID: 34834973 PMCID: PMC8618541 DOI: 10.3390/v13112167] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/23/2021] [Accepted: 10/24/2021] [Indexed: 11/23/2022] Open
Abstract
Bovine leukaemia virus (BLV) is a deltaretrovirus that is closely related to human T-cell leukaemia virus types 1 and 2 (HTLV-1 and -2). It causes enzootic bovine leukosis (EBL), which is the most important neoplastic disease in cattle. Most BLV-infected cattle are asymptomatic, which potentiates extremely high shedding rates of the virus in many cattle populations. Approximately 30% of them show persistent lymphocytosis that has various clinical outcomes; only a small proportion of animals (less than 5%) exhibit signs of EBL. BLV causes major economic losses in the cattle industry, especially in dairy farms. Direct costs are due to a decrease in animal productivity and in cow longevity; indirect costs are caused by restrictions that are placed on the import of animals and animal products from infected areas. Most European regions have implemented an efficient eradication programme, yet BLV prevalence remains high worldwide. Control of the disease is not feasible because there is no effective vaccine against it. Therefore, detection and early diagnosis of the disease are essential in order to diminish its spreading and the economic losses it causes. This review comprises an overview of bovine leukosis, which highlights the epidemiology of the disease, diagnostic tests that are used and effective control strategies.
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Affiliation(s)
- Marawan A. Marawan
- The State Key Laboratory of Agricultural Microbiology, Huazhong Agriculture University, Wuhan 430070, China; (I.S.); (A.D.)
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt;
- Correspondence: (M.A.M.); (A.G.); (A.S.)
| | - Abdulaziz Alouffi
- King Abdulaziz City for Science and Technology, Riyadh 12354, Saudi Arabia;
- The Chair of Vaccines Research for Infectious Diseases, King Saud University, Riyadh 11495, Saudi Arabia;
| | - Suleiman El Tokhy
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Tanta University, Tanta 31111, Egypt;
| | - Sara Badawy
- Department of Pathology, Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt;
- Natural Reference Laboratory of Veterinary Drug Residues (HZAU), MAO Key Laboratory for Detection of Veterinary Drug Residues Huazhong Agricultural University, Wuhan 430070, China
| | - Ihsanullah Shirani
- The State Key Laboratory of Agricultural Microbiology, Huazhong Agriculture University, Wuhan 430070, China; (I.S.); (A.D.)
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Para-Clinic Department, Faculty of Veterinary Medicine, Jalalabad 2601, Afghanistan
| | - Ali Dawood
- The State Key Laboratory of Agricultural Microbiology, Huazhong Agriculture University, Wuhan 430070, China; (I.S.); (A.D.)
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Infectious Diseases, Medicine Department, Faculty of Veterinary Medicine, University of Sadat City, Sadat City 32897, Egypt
| | - Aizhen Guo
- The State Key Laboratory of Agricultural Microbiology, Huazhong Agriculture University, Wuhan 430070, China; (I.S.); (A.D.)
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
- Hubei International Scientific and Technological Cooperation Base of Veterinary Epidemiology, Huazhong Agricultural University, Wuhan 430070, China
- Correspondence: (M.A.M.); (A.G.); (A.S.)
| | - Mashal M. Almutairi
- The Chair of Vaccines Research for Infectious Diseases, King Saud University, Riyadh 11495, Saudi Arabia;
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh 22334, Saudi Arabia
| | - Fahdah Ayed Alshammari
- College of Sciences and Literature Microbiology, Nothern Border University, Arar 73211, Saudi Arabia;
| | - Abdelfattah Selim
- Department of Animal Medicine (Infectious Diseases), Faculty of Veterinary Medicine, Benha University, Toukh 13736, Egypt;
- Correspondence: (M.A.M.); (A.G.); (A.S.)
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Predicted Cellular Interactors of the Endogenous Retrovirus-K Integrase Enzyme. Microorganisms 2021; 9:microorganisms9071509. [PMID: 34361946 PMCID: PMC8303831 DOI: 10.3390/microorganisms9071509] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/06/2021] [Accepted: 07/09/2021] [Indexed: 12/18/2022] Open
Abstract
Integrase (IN) enzymes are found in all retroviruses and are crucial in the retroviral integration process. Many studies have revealed how exogenous IN enzymes, such as the human immunodeficiency virus (HIV) IN, contribute to altered cellular function. However, the same consideration has not been given to viral IN originating from symbionts within our own DNA. Endogenous retrovirus-K (ERVK) is pathologically associated with neurological and inflammatory diseases along with several cancers. The ERVK IN interactome is unknown, and the question of how conserved the ERVK IN protein-protein interaction motifs are as compared to other retroviral integrases is addressed in this paper. The ERVK IN protein sequence was analyzed using the Eukaryotic Linear Motif (ELM) database, and the results are compared to ELMs of other betaretroviral INs and similar eukaryotic INs. A list of putative ERVK IN cellular protein interactors was curated from the ELM list and submitted for STRING analysis to generate an ERVK IN interactome. KEGG analysis was used to identify key pathways potentially influenced by ERVK IN. It was determined that the ERVK IN potentially interacts with cellular proteins involved in the DNA damage response (DDR), cell cycle, immunity, inflammation, cell signaling, selective autophagy, and intracellular trafficking. The most prominent pathway identified was viral carcinogenesis, in addition to select cancers, neurological diseases, and diabetic complications. This potentiates the role of ERVK IN in these pathologies via protein-protein interactions facilitating alterations in key disease pathways.
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Salamat MKF, Gossner A, Bradford B, Hunter N, Hopkins J, Houston F. Scrapie infection and endogenous retroviral expression in sheep lymphoid tissues. Vet Immunol Immunopathol 2021; 233:110194. [PMID: 33530020 DOI: 10.1016/j.vetimm.2021.110194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 12/28/2020] [Accepted: 01/08/2021] [Indexed: 01/09/2023]
Abstract
Transmissible spongiform encephalopathies, or prion diseases, are fatal neurodegenerative diseases affecting humans and animals. Although many host tissues express PrPC (essential for prion replication), relatively few cell types accumulate significant levels of infectivity, including neurons and other cell types in the nervous system, and follicular dendritic cells in secondary lymphoid organs. This suggests that tissue or cell-specific receptors or cofactors could play a role in controlling differential susceptibility to infection. Endogenous retroviruses (ERV), the remnants of ancient retroviral integration into the host germline, may represent one such cofactor. We examined the effect of scrapie infection on expression of three ovine ERV families (enJSRV/β1-OERV, γ1-OERV, γ2-OERV) in secondary lymphoid tissues of sheep at different time points following subcutaneous inoculation, using RT-qPCR. These OERVs were constitutively expressed in the prescapular lymph node and spleen of uninfected sheep. However, we were unable to find convincing evidence of specific differential expression of OERV in the same tissues following scrapie infection, in contrast to previous studies of ERV expression in brains of prion-infected mice and macaques. This study is the first to quantify the expression of potentially functional OERV transcripts in sheep lymphoid tissues, opening up interesting questions about the consequences for host immune function.
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Affiliation(s)
- M K F Salamat
- Division of Infection and Immunity, The Roslin Institute, R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - A Gossner
- Division of Infection and Immunity, The Roslin Institute, R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - B Bradford
- Division of Infection and Immunity, The Roslin Institute, R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - N Hunter
- Division of Infection and Immunity, The Roslin Institute, R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - J Hopkins
- Division of Infection and Immunity, The Roslin Institute, R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - F Houston
- Division of Infection and Immunity, The Roslin Institute, R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
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Chiu ES, VandeWoude S. Endogenous Retroviruses Drive Resistance and Promotion of Exogenous Retroviral Homologs. Annu Rev Anim Biosci 2020; 9:225-248. [PMID: 33290087 DOI: 10.1146/annurev-animal-050620-101416] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Endogenous retroviruses (ERVs) serve as markers of ancient viral infections and provide invaluable insight into host and viral evolution. ERVs have been exapted to assist in performing basic biological functions, including placentation, immune modulation, and oncogenesis. A subset of ERVs share high nucleotide similarity to circulating horizontally transmitted exogenous retrovirus (XRV) progenitors. In these cases, ERV-XRV interactions have been documented and include (a) recombination to result in ERV-XRV chimeras, (b) ERV induction of immune self-tolerance to XRV antigens, (c) ERV antigen interference with XRV receptor binding, and (d) interactions resulting in both enhancement and restriction of XRV infections. Whereas the mechanisms governing recombination and immune self-tolerance have been partially determined, enhancement and restriction of XRV infection are virus specific and only partially understood. This review summarizes interactions between six unique ERV-XRV pairs, highlighting important ERV biological functions and potential evolutionary histories in vertebrate hosts.
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Affiliation(s)
- Elliott S Chiu
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA; ,
| | - Sue VandeWoude
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA; ,
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Molaee V, Bazzucchi M, De Mia GM, Otarod V, Abdollahi D, Rosati S, Lühken G. Phylogenetic analysis of small ruminant lentiviruses in Germany and Iran suggests their expansion with domestic sheep. Sci Rep 2020; 10:2243. [PMID: 32042070 PMCID: PMC7010740 DOI: 10.1038/s41598-020-58990-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 01/21/2020] [Indexed: 11/09/2022] Open
Abstract
Small ruminant lentiviruses (SRLVs) are found in sheep in Germany and Iran. SRLVs have been classified into four genotypes: A-C and E. Genotype A has been subdivided into 20 subtypes. Previous studies suggested that, first, the ancestors of genotype A are those SRLVs found in Turkey, second, the evolution of SRLVs is related to the domestication process, and, third, SRLV infection was first observed in sheep in Iceland and the source of that infection was a flock imported from Germany. This study generated, for the first time, partial SRLV sequence data from German and Iranian sheep, enhancing our knowledge of the genetic and evolutionary relationships of SRLVs, and their associations with the domestication process. Based on 54 SRLV sequences from German and Iranian sheep, our results reveal: (1) SRLV subtypes A4, A5, A11, A16 and A21 (new) are found in German sheep and A22 (new) in Iranian sheep. (2) Genotype A has potentially an additional ancestor (A22), found in Iran, Lebanon and Jordan. (3) Subtype A22 is likely an old version of SRLVs. (4) The transmission routes of some SRLVs are compatible with domestication pathways. (5) This study found no evidence of Icelandic subtype A1 in German sheep.
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Affiliation(s)
- Vahid Molaee
- Institute of Animal Breeding and Genetics, Justus Liebig University Giessen (JLU), Ludwigstraße 21, 35390, Gießen, Germany.
| | - Moira Bazzucchi
- Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche Togo Rosati (IZSUM), Via G. Salvemini 1, 06126, Perugia, Italy
| | - Gian Mario De Mia
- Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche Togo Rosati (IZSUM), Via G. Salvemini 1, 06126, Perugia, Italy
| | - Vahid Otarod
- Quarantine and Biosafety Directorate General, Iran Veterinary Organization (IVO), Vali Asr Avenue, Seyed Jamaledin Asad Abadi Street, 6349, Tehran, Iran
| | - Darab Abdollahi
- Bureau of Animal Health and Disease Management, Iran Veterinary Organization (IVO), Vali Asr Avenue, Seyed Jamaledin Asad Abadi Street, 6349, Tehran, Iran
| | - Sergio Rosati
- Department of Veterinary Science, University of Turin (UNITO), Largo Paolo Braccini 2, 10095, Grugliasco, Torino, Italy
| | - Gesine Lühken
- Institute of Animal Breeding and Genetics, Justus Liebig University Giessen (JLU), Ludwigstraße 21, 35390, Gießen, Germany
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Chung HC, Nguyen VG, Oh WT, Huynh TML, Moon HJ, Lee JH, Kim HK, Park SJ, Park BK. Inhibition of Porcine Endogenous Retrovirus by Multi-Targeting Micro RNA Against Long Terminal Region. Transplant Proc 2018; 49:2225-2232. [PMID: 29149987 DOI: 10.1016/j.transproceed.2017.09.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/21/2017] [Accepted: 09/02/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND There might be much benefit in xenotransplantation, however, the risk of infections across species barriers remains, especially porcine endogenous retrovirus (PERV). To date, many attempts have been made to knock down active PERVs by inhibitory RNA (RNAi) and micro RNA (miRNA), which target different genes of PERV. There are a few studies that have explored whether targeting promoter regions of PERV could exert an inhibition effect. METHODS miRNAs were automatically selected based on an online program BLOCK-iT RNAi Designer. The inhibition efficiency between miRNAs was compared based on their inhibition of different PERV genes: long terminal repeats (LTR), gag, and pol. Both relative quantitative real-time polymerase chain reaction (PCR) and C-type reverse transcriptase activity were performed. RESULTS The results demonstrated that miRNA targeting the LTR region degraded the target sequence, and simultaneously inhibited the mRNA expression of both gag and pol genes of PERV. The LTR1, LTR2, and dual LTR1 + LTR2 miRNA inhibited 76.2%, 22%, and 76.8% of gag gene expression, respectively. Similarly, the miRNA was found to knock down the pol gene expression of 69.8%, 25.5%, and 77.7% for single targeting miRNA (LTR1 and LTR2) and multi-targeting miRNA (LTR1 + LTR2), respectively. A stable PK15 clone constitutively expressed dual LTR1 + LTR2 miRNA and exhibited higher inhibitory up to 82.8% and 92.7% of the expressions of the gag and pol genes, respectively. Also, the result of co-cultivation of dual LTR1 + LTR2 miRNA transfected PK15 cell with a human cell line inhibited expression of LTR, gag, and pol genes of PERV. CONCLUSIONS In conclusion, this study suggested that the LTR might be an alternative target for gene silencing of PERV, and that multi-targeting miRNA had better inhibitory effect than single- targeting miRNA. In an in vitro model, the presence of miRNA was able to reduce PERV infectivity in a human cell line.
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Affiliation(s)
- H-C Chung
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - V-G Nguyen
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - W-T Oh
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - T-M-L Huynh
- Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - H-J Moon
- Research Unit, Green Cross Veterinary Products, Yongin, Republic of Korea
| | - J-H Lee
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
| | - H-K Kim
- Viral Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - S-J Park
- Forensic Medicine Division, Daegu Institute, National Forensic Service, Chilgok, Korea
| | - B-K Park
- Department of Veterinary Medicine Virology Laboratory, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea.
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Expression patterns of endogenous avian retrovirus ALVE1 and its response to infection with exogenous avian tumour viruses. Arch Virol 2016; 162:89-101. [PMID: 27686071 DOI: 10.1007/s00705-016-3086-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 09/21/2016] [Indexed: 02/01/2023]
Abstract
Endogenous retroviruses (ERVs) are genomic elements that are present in a wide range of vertebrates and have been implicated in a variety of human diseases, including cancer. However, the characteristic expression patterns of ERVs, particularly in virus-induced tumours, is not fully clear. DNA methylation was analysed by bisulfite pyrosequencing, and gene expression was analysed by RT-qPCR. In this study, we first found that the endogenous avian retrovirus ALVE1 was highly expressed in some chicken tissues (including the heart, bursa, thymus, and spleen) at 2 days of age, but its expression was markedly decreased at 35 days of age. In contrast, the CpG methylation level of ALVE1 was significantly lower in heart and bursa at 2 days than at 35 days of age. Moreover, we found that the expression of ALVE1 was significantly inhibited in chicken embryo fibroblast cells (CEFs) and MSB1 cells infected with avian leukosis virus subgroup J (ALVJ) and reticuloendotheliosis virus (REV) at the early stages of infection. In contrast, the expression of the ALVE1 env gene was significantly induced in CEFs and MSB1 cells infected with Marek's disease virus (MDV). However, the methylation and expression levels of the ALVE1 long terminal repeat (LTR) did not show obvious alterations in response to viral infection. The present study revealed the expression patterns of ALVE1 in a variety of chicken organs and tissues and in chicken cells in response to avian tumour virus infection. These findings may be of significance for understanding the role and function of ERVs that are present in the host genome.
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Garcia-Etxebarria K, Jugo BM. Genome-wide reexamination of endogenous retroviruses in Rattus norvegicus. Virology 2016; 494:119-28. [PMID: 27107945 DOI: 10.1016/j.virol.2016.04.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 04/02/2016] [Accepted: 04/04/2016] [Indexed: 01/18/2023]
Abstract
Endogenous retroviruses (ERVs) are remnants of retroviral infections that are present in a large number of vertebrate genomes. Based on the proposal that the rat could act as a reservoir of retroviruses, rat ERVs were analysed in silico using a whole-genome approach. To enrich the detected ERV groups, we applied an upgraded approach based on the hidden Markov model. We found 2637 elements that were classified into the following groups: 9 groups of Class I; 15 of Class II, 7 of them previously described; 1 of Class III; and 3 groups whose classification was unclear but were distantly related to Class I. Sixteen ERV groups seemed to be specific to rat. The high number of rat-specific groups might be related to the contact of rats with retroviruses and their role as a reservoir. In addition, the env gene of the more extended groups seemed to be undetectable.
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Affiliation(s)
- Koldo Garcia-Etxebarria
- Genetika, Antropologia Fisikoa eta Animalien Fisiologia Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU), 644 Postakutxa, E-48080 Bilbao, Spain
| | - Begoña M Jugo
- Genetika, Antropologia Fisikoa eta Animalien Fisiologia Saila, Zientzia eta Teknologia Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU), 644 Postakutxa, E-48080 Bilbao, Spain.
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Expression of the env gene from the avian endogenous retrovirus ALVE and regulation by miR-155. Arch Virol 2016; 161:1623-32. [PMID: 27016933 DOI: 10.1007/s00705-016-2833-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/16/2016] [Indexed: 01/17/2023]
Abstract
Endogenous retroviruses (ERVs) are important retroelements that reside in host genomes. However, ERV expression patterns and regulatory mechanisms are poorly understood. In this study, chicken embryo fibroblasts (CEFs) and MSB1 cells infected with Marek's disease virus (MDV) exhibited significantly increased expression of env from the endogenous retrovirus ALVE. In contrast, env expression was significantly lower in CEF and MSB1 cells infected with exogenous avian leukosis virus J (ALVJ) at the early infection stage. Furthermore, env was found to be ubiquitously expressed in various chicken tissues, with high expression in certain tissues at 2 days of age and low levels in most tissues, including immune organs (thymus, spleen and bursa) as well as the brain and heart, at 35 days of age. Sequence analysis revealed miR-155 target sites in env transcripts, which was verified using a firefly luciferase reporter assay, and treatment with miR-155 agomir significantly decreased levels of env transcripts in MSB1 and CEF cells. Together, these findings suggest that the env gene from the endogenous retrovirus ALVE is regulated by miR-155.
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