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Tan L, Li J, Duan Y, Liu J, Zheng S, Liang X, Fang C, Zuo M, Tian G, Yang Y. Current knowledge on the epidemiology and prevention of Avian leukosis virus in China. Poult Sci 2024; 103:104009. [PMID: 39002365 PMCID: PMC11298916 DOI: 10.1016/j.psj.2024.104009] [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] [Received: 04/23/2024] [Revised: 05/26/2024] [Accepted: 06/19/2024] [Indexed: 07/15/2024] Open
Abstract
Avian leukosis virus (ALV) is an enveloped retrovirus with a single-stranded RNA genome, belonging to the genus Alpharetrovirus within the family Retroviridae. The disease (Avian leukosis, AL) caused by ALV is mainly characterized by tumor development and immunosuppression in chickens, which increases susceptibility to other pathogens and leads to significant economic losses in the Chinese poultry industry. The government and poultry industry have made lots of efforts to eradicate ALV, but the threat of which remains not vanished. This review provides a summary of the updated understanding of ALV in China, which mainly focuses on genetic and molecular biology, epidemiology, and diagnostic methods. Additionally, promising antiviral agents and ALV eradication strategies performed in China are also included.
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Affiliation(s)
- Lei Tan
- College of Animal Science and Technology, Yangtze University, Jingzhou, China; Yunnan Sino-Science Gene Technology Co. Ltd. Kunming, Yunnan, China
| | - Juan Li
- Yunnan Sino-Science Gene Technology Co. Ltd. Kunming, Yunnan, China; Hunan Provincial Key Laboratory of the TCM Agricultural Biogenomics, Changsha Medical University, Changsha, Hunan, China
| | - Yuqing Duan
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Jing Liu
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Shiling Zheng
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Xiongyan Liang
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Chun Fang
- College of Animal Science and Technology, Yangtze University, Jingzhou, China
| | - Mengting Zuo
- Hunan Provincial Key Laboratory of the TCM Agricultural Biogenomics, Changsha Medical University, Changsha, Hunan, China
| | - Guangming Tian
- College of Animal Science and Technology, Yangtze University, Jingzhou, China.
| | - Yuying Yang
- College of Animal Science and Technology, Yangtze University, Jingzhou, China.
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Matoušková M, Plachý J, Kučerová D, Pecnová Ľ, Reinišová M, Geryk J, Karafiát V, Hron T, Hejnar J. Rapid adaptive evolution of avian leukosis virus subgroup J in response to biotechnologically induced host resistance. PLoS Pathog 2024; 20:e1012468. [PMID: 39146367 PMCID: PMC11349186 DOI: 10.1371/journal.ppat.1012468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 08/27/2024] [Accepted: 07/29/2024] [Indexed: 08/17/2024] Open
Abstract
Genetic editing of the germline using CRISPR/Cas9 technology has made it possible to alter livestock traits, including the creation of resistance to viral diseases. However, virus adaptability could present a major obstacle in this effort. Recently, chickens resistant to avian leukosis virus subgroup J (ALV-J) were developed by deleting a single amino acid, W38, within the ALV-J receptor NHE1 using CRISPR/Cas9 genome editing. This resistance was confirmed both in vitro and in vivo. In vitro resistance of W38-/- chicken embryonic fibroblasts to all tested ALV-J strains was shown. To investigate the capacity of ALV-J for further adaptation, we used a retrovirus reporter-based assay to select adapted ALV-J variants. We assumed that adaptive mutations overcoming the cellular resistance would occur within the envelope protein. In accordance with this assumption, we isolated and sequenced numerous adapted virus variants and found within their envelope genes eight independent single nucleotide substitutions. To confirm the adaptive capacity of these substitutions, we introduced them into the original retrovirus reporter. All eight variants replicated effectively in W38-/- chicken embryonic fibroblasts in vitro while in vivo, W38-/- chickens were sensitive to tumor induction by two of the variants. Importantly, receptor alleles with more extensive modifications have remained resistant to the virus. These results demonstrate an important strategy in livestock genome engineering towards antivirus resistance and illustrate that cellular resistance induced by minor receptor modifications can be overcome by adapted virus variants. We conclude that more complex editing will be necessary to attain robust resistance.
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Affiliation(s)
- Magda Matoušková
- Department of Viral and Cellular Genetics, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Jiří Plachý
- Department of Viral and Cellular Genetics, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Dana Kučerová
- Department of Viral and Cellular Genetics, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Ľubomíra Pecnová
- Department of Viral and Cellular Genetics, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Markéta Reinišová
- Department of Viral and Cellular Genetics, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Josef Geryk
- Department of Viral and Cellular Genetics, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Vít Karafiát
- Department of Viral and Cellular Genetics, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Tomáš Hron
- Department of Viral and Cellular Genetics, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
| | - Jiří Hejnar
- Department of Viral and Cellular Genetics, Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic
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Mo G, Wei P, Hu B, Nie Q, Zhang X. Advances on genetic and genomic studies of ALV resistance. J Anim Sci Biotechnol 2022; 13:123. [PMID: 36217167 PMCID: PMC9550310 DOI: 10.1186/s40104-022-00769-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 08/14/2022] [Indexed: 12/01/2022] Open
Abstract
Avian leukosis (AL) is a general term for a variety of neoplastic diseases in avian caused by avian leukosis virus (ALV). No vaccine or drug is currently available for the disease. Therefore, the disease can result in severe economic losses in poultry flocks. Increasing the resistance of poultry to ALV may be one effective strategy. In this review, we provide an overview of the roles of genes associated with ALV infection in the poultry genome, including endogenous retroviruses, virus receptors, interferon-stimulated genes, and other immune-related genes. Furthermore, some methods and techniques that can improve ALV resistance in poultry are discussed. The objectives are willing to provide some valuable references for disease resistance breeding in poultry.
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Affiliation(s)
- Guodong Mo
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China.,Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, 510642, Guangdong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Ping Wei
- Institute for Poultry Science and Health, Guangxi University, Nanning, 530001, Guangxi, China
| | - Bowen Hu
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China.,Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, 510642, Guangdong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Qinghua Nie
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China.,Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, 510642, Guangdong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Xiquan Zhang
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, 510642, Guangdong, China. .,Key Lab of Chicken Genetics, Breeding and Reproduction, Ministry of Agriculture, Guangzhou, 510642, Guangdong, China. .,State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, 510642, Guangdong, China.
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Suzuki T, Morimoto N, Akaike A, Osakada F. Multiplex Neural Circuit Tracing With G-Deleted Rabies Viral Vectors. Front Neural Circuits 2020; 13:77. [PMID: 31998081 PMCID: PMC6967742 DOI: 10.3389/fncir.2019.00077] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 11/14/2019] [Indexed: 12/26/2022] Open
Abstract
Neural circuits interconnect to organize large-scale networks that generate perception, cognition, memory, and behavior. Information in the nervous system is processed both through parallel, independent circuits and through intermixing circuits. Analyzing the interaction between circuits is particularly indispensable for elucidating how the brain functions. Monosynaptic circuit tracing with glycoprotein (G) gene-deleted rabies viral vectors (RVΔG) comprises a powerful approach for studying the structure and function of neural circuits. Pseudotyping of RVΔG with the foreign envelope EnvA permits expression of transgenes such as fluorescent proteins, genetically-encoded sensors, or optogenetic tools in cells expressing TVA, a cognate receptor for EnvA. Trans-complementation with rabies virus glycoproteins (RV-G) enables trans-synaptic labeling of input neurons directly connected to the starter neurons expressing both TVA and RV-G. However, it remains challenging to simultaneously map neuronal connections from multiple cell populations and their interactions between intermixing circuits solely with the EnvA/TVA-mediated RV tracing system in a single animal. To overcome this limitation, here, we multiplexed RVΔG circuit tracing by optimizing distinct viral envelopes (oEnvX) and their corresponding receptors (oTVX). Based on the EnvB/TVB and EnvE/DR46-TVB systems derived from the avian sarcoma leukosis virus (ASLV), we developed optimized TVB receptors with lower or higher affinity (oTVB-L or oTVB-H) and the chimeric envelope oEnvB, as well as an optimized TVE receptor with higher affinity (oTVE-H) and its chimeric envelope oEnvE. We demonstrated independence of RVΔG infection between the oEnvA/oTVA, oEnvB/oTVB, and oEnvE/oTVE systems and in vivo proof-of-concept for multiplex circuit tracing from two distinct classes of layer 5 neurons targeting either other cortical or subcortical areas. We also successfully labeled common input of the lateral geniculate nucleus to both cortico-cortical layer 5 neurons and inhibitory neurons of the mouse V1 with multiplex RVΔG tracing. These oEnvA/oTVA, oEnvB/oTVB, and oEnvE/oTVE systems allow for differential labeling of distinct circuits to uncover the mechanisms underlying parallel processing through independent circuits and integrated processing through interaction between circuits in the brain.
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Affiliation(s)
- Toshiaki Suzuki
- Laboratory of Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
| | - Nao Morimoto
- Laboratory of Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan.,Laboratory of Neural Information Processing, Institute for Advanced Research, Nagoya University, Nagoya, Japan
| | - Akinori Akaike
- Laboratory of Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
| | - Fumitaka Osakada
- Laboratory of Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan.,Laboratory of Neural Information Processing, Institute for Advanced Research, Nagoya University, Nagoya, Japan.,Institute of Nano-Life-Systems, Institutes of Innovation for Future Society, Nagoya University, Nagoya, Japan.,PRESTO/CREST, Japan Science and Technology Agency, Saitama, Japan
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Elamurugan A, Karthik K, Badasara SK, Hajam IA, Saravanan M. Novel insights into identification of shedders and transmitters of avian leukosis virus. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2015. [DOI: 10.1016/s2222-1808(15)60889-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
The retrovirus family contains several important human and animal pathogens, including the human immunodeficiency virus (HIV), the causative agent of acquired immunodeficiency syndrome (AIDS). Studies with retroviruses were instrumental to our present understanding of the cellular entry of enveloped viruses in general. For instance, studies with alpharetroviruses defined receptor engagement, as opposed to low pH, as a trigger for the envelope protein-driven membrane fusion. The insights into the retroviral entry process allowed the generation of a new class of antivirals, entry inhibitors, and these therapeutics are at present used for treatment of HIV/AIDS. In this chapter, we will summarize key concepts established for entry of avian sarcoma and leukosis virus (ASLV), a widely used model system for retroviral entry. We will then review how foamy virus and HIV, primate- and human retroviruses, enter target cells, and how the interaction of the viral and cellular factors involved in the cellular entry of these viruses impacts viral tropism, pathogenesis and approaches to therapy and vaccine development.
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Asimakopoulos F, Varmus HE. Cell-specific transduction of Prdm1-expressing lineages mediated by a receptor for avian leukosis virus subgroup B. J Virol 2009; 83:4835-43. [PMID: 19279099 PMCID: PMC2682090 DOI: 10.1128/jvi.02254-08] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 03/02/2009] [Indexed: 02/01/2023] Open
Abstract
The transcription factor Blimp-1 has emerged as a regulator of cell fate in embryonic (germ cell) and adult (B- and T-cell immune effector and epithelial) lineages. It has also been proposed to act as a tumor suppressor in B-cell malignancy. Here, we present a novel in vivo system enabling the targeted genetic manipulation of cells expressing Prdm1, the gene encoding Blimp-1. We created bacterial artificial chromosome-transgenic mice expressing the avian leukosis virus (ALV) receptor TVB, fused to monomeric red fluorescent protein, under regulation by Prdm1 transcriptional elements, and we achieved transduction of TVB-expressing lymphocytes by ALV vectors bearing a subgroup B envelope. The system presented here incorporates a number of innovations. First, it is the first mammalian transgenic system that employs the ALV receptor TVB, thus expanding the flexibility and scope of ALV-mediated gene delivery. Second, it represents the first ALV-based system that allows gene transfer and expression into in vivo-activated mature lymphocytes, a cell type that has traditionally presented formidable challenges to efficient retroviral transduction. Third, Prdm1:TVB-mRFP transgenic animals could provide an invaluable tool for exploring the diverse roles of Blimp-1 in lineage commitment, immune regulation, and tumorigenesis.
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Affiliation(s)
- Fotis Asimakopoulos
- Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
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8
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Functional genetic screening reveals the role of mitochondrial cytochrome b as a mediator of FAS-induced apoptosis. Proc Natl Acad Sci U S A 2008; 105:14453-8. [PMID: 18796602 DOI: 10.1073/pnas.0807549105] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Functional selection of genetic suppressor elements (GSEs), engineered gene fragments that interfere with the function of a particular gene product, was used to identify regulators of FAS-induced apoptosis. Chicken DF-1 cells expressing human FAS receptor and susceptible to FAS-induced apoptosis were infected with a GSE library consisting of randomly fragmented normalized chicken cDNAs in a replication-competent avian retroviral vector. Virus-producing cells were subjected to several rounds of selection using FAS agonistic antibodies, resulting in isolation of a set of GSEs conferring resistance to FAS-induced apoptosis. Surprisingly, one of the isolated GSEs encoded a 42 amino acid-long polypeptide derived from the C-terminal half of cytochrome b (Cyt b) encoded by the mitochondrial genome. Subsequent experiments showed that caspase 8-dependent cleavage of mitochondrial Cyt b and translocation of its C-terminal half into the cytoplasm occurred during FAS-induced apoptosis in both chicken and human cells. Ectopic cytoplasmic expression of either full-length Cyt b or its C-terminal half in several human cell lines induced apoptosis, which could be suppressed by the isolated GSE, but not by Bcl2 over-expression or Apaf-1 or cytochrome c knock-down. These results reveal a cytochrome c-independent branch of FAS-induced apoptosis involving cleavage and cytoplasmic release of mitochondrial Cyt b.
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9
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Zhang HM, Bacon LD, Heidari M, Muir WM, Groenen MAM, Zhang Y, Wong GKS, Fulton JE, O'Sullivan NP, Albers GAA, Vereijken ALJ, Rattink AP, Okimoto R, McKay JC, McLeod S, Cheng HH. Genetic variation at the tumour virus B locus in commercial and laboratory chicken populations assessed by a medium-throughput or a high-throughput assay. Avian Pathol 2007; 36:283-91. [PMID: 17620174 DOI: 10.1080/03079450701449248] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The tumour virus B (TVB) locus encodes cellular receptors mediating infection by three subgroups of avian leukosis virus (B, D, and E). Three major alleles, TVB*S1, TVB*S3, and TVB*R, have been described. TVB*S1 encodes a cellular receptor mediating infection of subgroups B, D, and E. TVB*S3 encodes the receptor for two subgroups, B and D, and TVB*R encodes a dysfunctional receptor that does not permit infection by any of the subgroups, B, D, or E. Genetic diversity at the TVB locus of chickens was investigated in both layer and broiler commercial pure lines and laboratory lines. Genotyping assays were developed for both medium-throughput and high-throughput analysis. Of the 36 broiler lines sampled, 14 were fixed for the susceptible allele TVB*S1. Across all broiler lines, 83% of chickens were typed as TVB*S1/*S1, 3% as TVB*R/*R, and 14% as TVB*S1/*R. In the egg-layer lines, five of the 16 tested were fixed for TVB*S1/*S1. About 44% of egg-layers were typed as TVB*S1/*S1, 15% as TVB*R/*R, with the rest segregating for two or three of the alleles. In the laboratory chickens, 60% were fixed for TVB*S1/*S1, 6% for TVB*S3/*S3, 14% for TVB*R/*R, and the rest were heterozygotes (TVB*S1/*S3 or TVB*S1/*R). All commercial pure lines examined in this study carry the TVB*S1 allele that sustains the susceptibility to avian leukosis viruses B, D, and E. More importantly, the TVB*R allele was identified in multiple populations, thus upholding the opportunities for genetic improvement through selection.
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Affiliation(s)
- H M Zhang
- USDA, ARS, Avian Disease and Oncology Laboratory, East Lansing, MI 48823, USA.
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Silva RF, Fadly AM, Taylor SP. Development of a Polymerase Chain Reaction to Differentiate Avian Leukosis Virus (ALV) Subgroups: Detection of an ALV Contaminant in Commercial Marek's Disease Vaccines. Avian Dis 2007; 51:663-7. [DOI: 10.1637/0005-2086(2007)51[663:doapcr]2.0.co;2] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Li YP, Handberg KJ, Juul-Madsen HR, Zhang MF, Jørgensen PH. Transcriptional profiles of chicken embryo cell cultures following infection with infectious bursal disease virus. Arch Virol 2006; 152:463-78. [PMID: 17143781 DOI: 10.1007/s00705-006-0878-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Accepted: 10/17/2006] [Indexed: 12/22/2022]
Abstract
Infectious bursal disease virus (IBDV) is the causative agent of infectious bursal disease in chickens and causes a significant economic loss for the poultry industry. Little is understood about the mechanism involved in the host responses to IBDV infection. For better understanding the IBDV-host interaction, we measured steady-state levels of transcripts from 28 cellular genes of chicken embryo (CE) cell cultures infected with IBDV vaccine stain Bursine-2 during a 7-day infection course by use of the quantitative real-time RT-PCR SYBR green method. Of the genes tested, 21 genes (IRF-1, IFN 1-2 promoter, IFNAR-1, IRF-10, IFN-gamma, 2',5'-OAS, IAP-1, caspase 8, TRAIL-like, STAT-3, IL-6, IL-8, MIP-3 alpha, MHC-I, MHC-II, TVB, GLVR-1, OTF, IL-13R alpha, ST3GAL-VI and PGK) showed an increased expression. The remaining seven genes (IFNAR-2, IFN-alpha, NF-kappaB subunit p65, BLRcp38, DDX1, G6PDH and UB) showed a constant expression or only slight alteration. Apparently, the host genes involved in pro-inflammatory response and apoptosis, interferon-regulated proteins, and the cellular immune response were affected by IBDV infection, indicating involvement in the complex signaling pathways of host responses to the infection. This study thus contributes to the understanding of the pathogenesis of IBD and provides an insight into the virus-host interaction.
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Affiliation(s)
- Y P Li
- Department of Poultry, Fish and Fur Animals, Danish Institute for Food and Veterinary Research, Aarhus, Denmark.
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Elleder D, Plachý J, Hejnar J, Geryk J, Svoboda J. Close linkage of genes encoding receptors for subgroups A and C of avian sarcoma/leucosis virus on chicken chromosome 28. Anim Genet 2004; 35:176-81. [PMID: 15147387 DOI: 10.1111/j.1365-2052.2004.01118.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Avian sarcoma and leucosis viruses (ASLV) are classified into six major subgroups (A to E and J) according to the properties of the viral envelope proteins and the usage of cellular receptors for virus entry. Subgroup A and B receptors are identified molecularly and their genomic positions TVA and TVB are mapped. The subgroup C receptor is unknown, its genomic locus TVC is reported to be genetically linked to TVA, which resides on chicken chromosome 28. In this study, we used two chicken inbred lines that carry different alleles coding for resistance (TVC(R) and sensitivity (TVC(S)) to infection by subgroup C viruses. A backross population of these lines was tested for susceptibility to subgroup C infection and genotyped for markers from chicken chromosome 28. We confirmed the close linkage between TVA and TVC loci. Further, we have described the position of TVC on chromosome 28 relative to markers from the consensus map of the chicken genome.
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Affiliation(s)
- D Elleder
- Department of Cellular and Viral Genetics, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, Prague, 166 37, Czech Republic
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Abstract
Infection by all enveloped viruses occurs via the fusion of viral and cellular membranes and delivery of the viral nucleocapsid into the cell cytoplasm, after association of the virus with cognate receptors at the cell surface. This process is mediated by viral fusion proteins anchored in the viral envelope and can be defined based on the requirement for low pH to trigger membrane fusion. In viruses that utilize a pH-dependent entry mechanism, such as influenza virus, viral fusion is triggered by the acidic environment of intracellular organelles after uptake of the virus from the cell surface and trafficking to a low-pH compartment. In contrast, in viruses that utilize a pH-independent entry mechanism, such as most retroviruses, membrane fusion is triggered solely by the interaction of the envelope glycoprotein with cognate receptors, often at the cell surface. However, recent work has indicated that the alpharetrovirus, avian sarcoma and leukosis virus (ASLV), utilizes a novel entry mechanism that combines aspects of both pH-independent and pH-dependent entry. In ASLV infection, the interaction of the envelope glycoprotein (Env) with cognate receptors at the cell surface causes an initial conformational change that primes (activates) Env and renders it sensitive to subsequent low-pH triggering from an intracellular compartment. Thus unlike other pH-dependent viruses, ASLV Env is only sensitive to low-pH triggering following interaction with its cognate receptor. In this manuscript we review current research on ASLV Env-receptor interactions and focus on the specific molecular requirements of both the viral fusion protein and cognate receptors for ASLV entry. In addition, we review data pertaining to the novel two-step entry mechanism of ASLV entry and propose a model by which ASLV Env elicits membrane fusion.
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Affiliation(s)
- R J O Barnard
- McArdle Laboratories for Cancer Research, Department of Oncology, University of Wisconsin Madison, 1400 University Ave, Madison, WI 53706, USA
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14
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Abstract
Alpharetroviruses provide a useful system for the study of the molecular mechanisms of host range and receptor interaction. These viruses can be divided into subgroups based on diverse receptor usage due to variability within the two host range determining regions, hr1 and hr2, in their envelope glycoprotein SU (gp85). In previous work, our laboratory described selection from a subgroup B avian sarcoma-leukosis virus of an extended-host-range variant (LT/SI) with two adjacent amino acid substitutions in hr1. This virus retains its ability to use the subgroup BD receptor but can also infect QT6/BD cells, which bear a related subgroup E receptor (R. A. Taplitz and J. M. Coffin, J. Virol 71:7814-7819, 1997). Here, we report further analysis of this unusual variant. First, one (L154S) of the two substitutions is sufficient for host range extension, while the other (T155I) does not alter host range. Second, these mutations extend host range to non-avian cell types, including human, dog, cat, mouse, rat, and hamster. Third, interference experiments imply that the mutants interact efficiently with the subgroup BD receptor and possibly the related subgroup E receptor, but they have another means of entry that is not dependent on these interactions. Fourth, binding studies indicate that the mutant SU proteins retain the ability to interact as monomers with subgroup BD and BDE receptors but only bind the subgroup E receptor in the context of an Env trimer. Further, the mutant SU proteins bind well to chicken cells but do not bind any better than wild-type subgroup B to QT6 or human cells, even though the corresponding viruses are capable of infecting these cells.
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Affiliation(s)
- G Jonah A Rainey
- Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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Ochsenbauer-Jambor C, Delos SE, Accavitti MA, White JM, Hunter E. Novel monoclonal antibody directed at the receptor binding site on the avian sarcoma and leukosis virus Env complex. J Virol 2002; 76:7518-27. [PMID: 12097564 PMCID: PMC136349 DOI: 10.1128/jvi.76.15.7518-7527.2002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report here on the generation of a mouse monoclonal antibody directed against Rous sarcoma virus (RSV) subgroup A Env that will be useful in functional and structural analysis of RSV Env, as well as in approaches employing the RCAS/Tva system for gene targeting. BALB/c mice were primed and given boosters twice with EnvA-expressing NIH 3T3 cells. Resulting hybridomas were tested by enzyme-linked immunosorbent assay against RCANBP virions and SU-A-immunoglobulin G immunoadhesin. One highly reactive hybridoma clone, mc8C5, was subcloned and tested in immunofluorescence, immunoprecipitation (IP), and Western blotting assays. In all three assays, mc8C5-4 subgroup-specifically recognizes SR-A Env, through the SU domain, expressed from different vectors in both avian and mammalian cells. This multifunctionality is notable for a mouse monoclonal. We furthermore observed a preference for binding to terminally glycosylated Env over core-glycosylated Env precursor in IPs, suggesting that the epitope is at least partially conformational and dependent on glycosylation. Most importantly, we found mc8C5-4 inhibited Env function: in vitro, the monoclonal not only interferes with binding of the EnvA receptor, Tva, but it also blocks the Tva-induced conformational change required for activation of the fusion peptide, without inducing that change itself. Infection of Tva-expressing avian or mammalian cells by avian sarcoma and leukosis virus (ASLV) or EnvA-pseudotyped murine leukemia virus, respectively, is efficiently inhibited by mc8C5-4. The apparent interference of the monoclonal with the EnvA-Tva complex formation suggests that the epitope seen by mc8C5 overlaps with the receptor binding site. This is supported by the observation that mutations of basic residues in hr2 or of the downstream glycosylation site, which both impair Tva-binding to EnvA, have similar effects on the binding of mc8C5. Thus, anti-ASLV-SU-A mc8C5-4 proves to be a unique new immunoreagent that targets the receptor-binding site on a prototypical retroviral envelope.
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Klucking S, Adkins HB, Young JAT. Resistance to infection by subgroups B, D, and E avian sarcoma and leukosis viruses is explained by a premature stop codon within a resistance allele of the tvb receptor gene. J Virol 2002; 76:7918-21. [PMID: 12097608 PMCID: PMC136383 DOI: 10.1128/jvi.76.15.7918-7921.2002] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Here we present the first molecular characterization of the defect associated with an avian sarcoma and leukosis virus (ASLV) receptor resistance allele, tvb(r). We show that resistance to infection by subgroups B, D, and E ASLV is explained by the presence of a single base pair mutation that distinguishes this allele from tvb(s1), an allele which encodes a receptor for all three viral subgroups. This mutation generates an in-frame stop codon that is predicted to lead to the production of a severely truncated protein.
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Affiliation(s)
- Sara Klucking
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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18
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Knauss DJ, Young JAT. A fifteen-amino-acid TVB peptide serves as a minimal soluble receptor for subgroup B avian leukosis and sarcoma viruses. J Virol 2002; 76:5404-10. [PMID: 11991969 PMCID: PMC137033 DOI: 10.1128/jvi.76.11.5404-5410.2002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2001] [Accepted: 02/20/2002] [Indexed: 11/20/2022] Open
Abstract
The TVB receptor for subgroup B, D, and E avian sarcoma and leukosis viruses (ASLVs) is a tumor necrosis factor receptor-related protein that is most closely related to the TRAIL receptors. Here we show that the major subgroup B viral interaction determinants of TVB are contained within a linear 15-amino-acid peptide derived from the N-terminal region of the receptor. Moreover, this peptide was sufficient not only for binding to ASLV-B but also for activating viral entry into mammalian cells that lacked the cognate viral receptor. Peptide-dependent viral entry was blocked in the presence of bafilomycin A1, indicating that virions can be trafficked to an acidic endosomal fusion compartment without the need for physical attachment of the viral receptor to a cellular membrane.
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Affiliation(s)
- Daniel J Knauss
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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19
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Adkins HB, Blacklow SC, Young JA. Two functionally distinct forms of a retroviral receptor explain the nonreciprocal receptor interference among subgroups B, D, and E avian leukosis viruses. J Virol 2001; 75:3520-6. [PMID: 11264341 PMCID: PMC114843 DOI: 10.1128/jvi.75.8.3520-3526.2001] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2000] [Accepted: 01/16/2001] [Indexed: 11/20/2022] Open
Abstract
Subgroups B, D, and E avian leukosis viruses (ALV-B, -D, and -E) share the same chicken receptor, TVB(S1), a tumor necrosis factor receptor (TNFR)-related protein. These viruses, however, exhibit nonreciprocal receptor interference (NRI): cells preinfected with ALV-B or ALV-D are resistant to superinfection by viruses of all three subgroups, whereas those pre-infected by ALV-E are resistant only to superinfection by other subgroup E viruses. In this study, we investigated the basis of this phenomenon by characterizing the interaction of TVB(S1) with ALV-B Env or ALV-E Env. Sequential immunoprecipitation analysis using surface envelope immunoglobulin fusion proteins revealed the existence of two separate types of TVB(S1) that are encoded by the same cDNA clone. One form, designated the type 1 receptor, is specific for ALV-B and ALV-E. The other form, the type 2 receptor, is specific for ALV-B. We show that a protein consisting of only the first and second extracellular cysteine-rich domains of TVB(S1) is capable of forming both receptor types. However, the third extracellular cysteine-rich domain is required for efficient formation of the type 1 receptor. We also demonstrate that heterogeneous N-linked glycosylation cannot explain the difference in activities of the two receptor types. The existence of two types of TVB(S1) explains the NRI pattern between ALV-B and -E: subgroup B viruses establish receptor interference with both receptor types, whereas subgroup E viruses interfere only with the type 1 receptor, leaving the type 2 receptor available to mediate subsequent rounds of ALV-B entry. The formation of a TVB receptor type that is specific for cytopathic ALV may also have important implications for understanding how some subgroups of ALV cause cell death.
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Affiliation(s)
- H B Adkins
- Department of Microbiology and Molecular Genetics, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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20
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Brojatsch J, Naughton J, Adkins HB, Young JA. TVB receptors for cytopathic and noncytopathic subgroups of avian leukosis viruses are functional death receptors. J Virol 2000; 74:11490-4. [PMID: 11090145 PMCID: PMC112428 DOI: 10.1128/jvi.74.24.11490-11494.2000] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The identification of TVB(S3), a cellular receptor for the cytopathic subgroups B and D of avian leukosis virus (ALV-B and ALV-D), as a tumor necrosis factor receptor-related death receptor with a cytoplasmic death domain, provides a compelling argument that viral Env-receptor interactions are linked to cell death (4). However, other TVB proteins have been described that appear to have similar death domains but are cellular receptors for the noncytopathic subgroup E of ALV (ALV-E): TVB(T), a turkey subgroup E-specific ALV receptor, and TVB(S1), a chicken receptor for subgroups B, D, and E ALV. To begin to understand the role of TVB receptors in the cytopathic effects associated with infection by specific ALV subgroups, we asked whether binding of a soluble ALV-E surface envelope protein (SU) to its receptor can lead to cell death. Here we report that ALV-E SU-receptor interactions can induce apoptosis in quail or turkey cells. We also show directly that TVB(S1) and TVB(T) are functional death receptors that can trigger cell death by apoptosis via a mechanism involving their cytoplasmic death domains and activation of the caspase pathway. These data demonstrate that ALV-B and ALV-E use functional death receptors to enter cells, and it remains to be determined why only subgroups B and D viral infections lead specifically to cell death.
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Affiliation(s)
- J Brojatsch
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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21
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Holmen SL, Federspiel MJ. Selection of a subgroup A avian leukosis virus [ALV(A)] envelope resistant to soluble ALV(A) surface glycoprotein. Virology 2000; 273:364-73. [PMID: 10915607 DOI: 10.1006/viro.2000.0424] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The host developing resistance to retroviral infection is believed to be a major force in the evolution of multiple receptor usage by retroviruses. The avian leukosis-sarcoma virus (ALV) group of retroviruses provides a powerful system for studying the envelope-receptor interactions involved in retrovirus entry; different members of this group of closely related viruses use distinct cellular receptors. Analysis of the ALV envelope subgroups suggests that the different ALVs evolved from a common ancestor by mutations in the env gene. Cells and animals that express subgroup A ALV envelope glycoproteins are highly resistant to ALV(A) infection due to receptor interference. In this study, we tested whether expression of a soluble form of subgroup A surface glycoprotein (SU) would result in receptor interference and whether this interference would select for resistant viruses with altered receptor usage. Chicken cells expressing the secreted ALV(A) SU immunoadhesin SU(A)-rIgG, which contains the subgroup A SU domain fused to the constant region of a rabbit immunoglobulin (IgG) heavy chain, showed significant receptor interference. A variant virus resistant to SU(A)-rIgG receptor interference was obtained. This virus had a six-amino-acid deletion in the subgroup A hr1 that altered receptor usage. This approach may identify regions of SU that play a critical role in receptor specificity.
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Affiliation(s)
- S L Holmen
- Molecular Medicine Program, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA
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Adkins HB, Brojatsch J, Young JA. Identification and characterization of a shared TNFR-related receptor for subgroup B, D, and E avian leukosis viruses reveal cysteine residues required specifically for subgroup E viral entry. J Virol 2000; 74:3572-78. [PMID: 10729132 PMCID: PMC111866 DOI: 10.1128/jvi.74.8.3572-3578.2000] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/1999] [Accepted: 01/18/2000] [Indexed: 11/20/2022] Open
Abstract
Genetic and receptor interference data have indicated the presence of one or more cellular receptors for subgroup B, D, and E avian leukosis viruses (ALV) encoded by the s1 allele of the chicken tvb locus. Despite the prediction that these viruses use the same receptor, they exhibit a nonreciprocal receptor interference pattern: ALV-B and ALV-D can interfere with infection by all three viral subgroups, but ALV-E only interferes with infection by subgroup E viruses. We identified a tvb(s1) cDNA clone which encodes a tumor necrosis factor receptor-related receptor for ALV-B, -D, and -E. The nonreciprocal receptor interference pattern was reconstituted in transfected human 293 cells by coexpressing the cloned receptor with the envelope (Env) proteins of either ALV-B or ALV-E. This pattern of interference was also observed when soluble ALV surface (SU)-immunoglobulin fusion proteins were bound to this cellular receptor before viral challenge. These data demonstrate that viral Env-receptor interactions can account for the nonreciprocal interference between ALV subgroups B, D, and E. Furthermore, they indicate that a single chicken gene located at tvb(s1) encodes receptors for these three viral subgroups. The TVB(S1) protein differs exclusively at residue 62 from the published subgroup B- and D-specific receptor, encoded by the s3 allele of tvb. Residue 62 is a cysteine in TVB(S1) but is a serine in TVB(S3), giving TVB(S1) an even number of cysteines in the extracellular domain. We present evidence for a disulfide bond requirement in TVB(S1) for ALV-E infection but not for ALV-B infection. Thus, ALV-B and ALV-E interact in fundamentally different ways with this shared receptor, a finding that may account for the observed biological differences between these two ALV subgroups.
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Affiliation(s)
- H B Adkins
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Holmen SL, Salter DW, Payne WS, Dodgson JB, Hughes SH, Federspiel MJ. Soluble forms of the subgroup A avian leukosis virus [ALV(A)] receptor Tva significantly inhibit ALV(A) infection in vitro and in vivo. J Virol 1999; 73:10051-60. [PMID: 10559319 PMCID: PMC113056 DOI: 10.1128/jvi.73.12.10051-10060.1999] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The interactions between the subgroup A avian leukosis virus [ALV(A)] envelope glycoproteins and soluble forms of the ALV(A) receptor Tva were analyzed both in vitro and in vivo by quantitating the ability of the soluble Tva proteins to inhibit ALV(A) entry into susceptible cells. Two soluble Tva proteins were tested: the 83-amino-acid Tva extracellular region fused to two epitope tags (sTva) or fused to the constant region of the mouse immunoglobulin G heavy chain (sTva-mIgG). Replication-competent ALV-based retroviral vectors with subgroup B or C env were used to deliver and express the two soluble tv-a (stva) genes in avian cells. In vitro, chicken embryo fibroblasts or DF-1 cells expressing sTva or sTva-mIgG proteins were much more resistant to infection by ALV(A) ( approximately 200-fold) than were control cells infected by only the vector. The antiviral effect was specific for ALV(A), which is consistent with a receptor interference mechanism. The antiviral effect of sTva-mIgG was positively correlated with the amount of sTva-mIgG protein. In vivo, the stva genes were delivered and expressed in line 0 chicken embryos by the ALV(B)-based vector RCASBP(B). Viremic chickens expressed relatively high levels of stva and stva-mIgG RNA in a broad range of tissues. High levels of sTva-mIgG protein were detected in the sera of chickens infected with RCASBP(B)stva-mIgG. Viremic chickens infected with RCASBP(B) alone, RCASBP(B)stva, or RCASBP(B)stva-mIgG were challenged separately with ALV(A) and ALV(C). Both sTva and sTva-mIgG significantly inhibited infection by ALV(A) (95 and 100% respectively) but had no measurable effect on ALV(C) infection. The results of this study indicate that a soluble receptor can effectively block infection of at least some retroviruses and demonstrates the utility of the ALV experimental system in characterizing the mechanism(s) of viral entry.
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Affiliation(s)
- S L Holmen
- Molecular Medicine Program, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA
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Affiliation(s)
- Maja A Sommerfelt
- Centre for Research in Virology, Department of Microbiology and Immunology, The Gade Institute, University of Bergen, Bergen High Technology Centre, N-5020 Bergen, Norway1
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25
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Boerger AL, Snitkovsky S, Young JA. Retroviral vectors preloaded with a viral receptor-ligand bridge protein are targeted to specific cell types. Proc Natl Acad Sci U S A 1999; 96:9867-72. [PMID: 10449786 PMCID: PMC22302 DOI: 10.1073/pnas.96.17.9867] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Successful targeting methods represent a major hurdle to the use of retroviral vectors in cell-specific gene-delivery applications. We recently described an approach for retroviral targeting with a retroviral receptor-ligand bridge protein that was bound to the cognate cell-surface ligand receptors before viral challenge. We now report a significant improvement made to this viral targeting method by using a related bridge protein, designated TVB-EGF, comprised of the extracellular domain of the TVB receptor for subgroup B avian leukosis virus fused to epidermal growth factor (EGF). The most important activity of TVB-EGF was that it allowed specific viral entry when preloaded onto virions. Furthermore, virions preloaded with TVB-EGF were thermostable and could be produced directly from virus- packaging cells. These data suggest an approach for targeting retroviral vectors to specific cell types by using virions preloaded with a retroviral receptor-ligand bridge protein and indicate that these types of bridge proteins may be useful reagents for studying the normal mechanism of retroviral entry.
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Affiliation(s)
- A L Boerger
- Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Avenue, Boston MA 02115, USA
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