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Nozuma S, Jacobson S. Neuroimmunology of Human T-Lymphotropic Virus Type 1-Associated Myelopathy/Tropical Spastic Paraparesis. Front Microbiol 2019; 10:885. [PMID: 31105674 PMCID: PMC6492533 DOI: 10.3389/fmicb.2019.00885] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/05/2019] [Indexed: 12/14/2022] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) is the etiologic agent of both adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HAM/TSP is clinically characterized by chronic progressive spastic paraparesis, urinary incontinence, and mild sensory disturbance. Given its well-characterized clinical presentation and pathophysiology, which is similar to the progressive forms of multiple sclerosis (MS), HAM/TSP is an ideal system to better understand other neuroimmunological disorders such as MS. Since the discovery of HAM/TSP, large numbers of clinical, virological, molecular, and immunological studies have been published. The host-virus interaction and host immune response play an important role for the development with HAM/TSP. HTLV-1-infected circulating T-cells invade the central nervous system (CNS) and cause an immunopathogenic response against virus and possibly components of the CNS. Neural damage and subsequent degeneration can cause severe disability in patients with HAM/TSP. Little progress has been made in the discovery of objective biomarkers for grading stages and predicting progression of disease and the development of molecular targeted therapy based on the underlying pathological mechanisms. We review the recent understanding of immunopathological mechanism of HAM/TSP and discuss the unmet need for research on this disease.
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Affiliation(s)
- Satoshi Nozuma
- Viral Immunology Section, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Steven Jacobson
- Viral Immunology Section, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
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2
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Brenner N, Mentzer AJ, Butt J, Braband KL, Michel A, Jeffery K, Klenerman P, Gärtner B, Schnitzler P, Hill A, Taylor G, Demontis MA, Guy E, Hadfield SJ, Almond R, Allen N, Pawlita M, Waterboer T. Validation of Multiplex Serology for human hepatitis viruses B and C, human T-lymphotropic virus 1 and Toxoplasma gondii. PLoS One 2019; 14:e0210407. [PMID: 30615688 PMCID: PMC6322760 DOI: 10.1371/journal.pone.0210407] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/21/2018] [Indexed: 01/16/2023] Open
Abstract
Multiplex Serology is a high-throughput technology developed to simultaneously measure specific serum antibodies against multiple pathogens in one reaction vessel. Serological assays for hepatitis B (HBV) and C (HCV) viruses, human T-lymphotropic virus 1 (HTLV-1) and the protozoan parasite Toxoplasma gondii (T. gondii) were developed and validated against established reference assays. For each pathogen, between 3 and 5 specific antigens were recombinantly expressed as GST-tag fusion proteins in Escherichia coli and tested in Monoplex Serology, i.e. assays restricted to the antigens from one particular pathogen. For each of the four pathogen-specific Monoplex assays, overall seropositivity was defined using two pathogen-specific antigens. In the case of HBV Monoplex Serology, the detection of past natural HBV infection was validated based on two independent reference panels resulting in sensitivities of 92.3% and 93.0%, and specificities of 100% in both panels. Validation of HCV and HTLV-1 Monoplex Serology resulted in sensitivities of 98.0% and 95.0%, and specificities of 96.2% and 100.0%, respectively. The Monoplex Serology assay for T. gondii was validated with a sensitivity of 91.2% and specificity of 92.0%. The developed Monoplex Serology assays largely retained their characteristics when they were included in a multiplex panel (i.e. Multiplex Serology), containing additional antigens from a broad range of other pathogens. Thus HBV, HCV, HTLV-1 and T. gondii Monoplex Serology assays can efficiently be incorporated into Multiplex Serology panels tailored for application in seroepidemiological studies.
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Affiliation(s)
- Nicole Brenner
- Infections and Cancer Epidemiology, Infection, Inflammation and Cancer Research Program, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Alexander J. Mentzer
- The Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Julia Butt
- Infections and Cancer Epidemiology, Infection, Inflammation and Cancer Research Program, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Kathrin L. Braband
- Infections and Cancer Epidemiology, Infection, Inflammation and Cancer Research Program, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Angelika Michel
- Infections and Cancer Epidemiology, Infection, Inflammation and Cancer Research Program, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Katie Jeffery
- Department of Microbiology, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
| | - Paul Klenerman
- Department of Microbiology, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom
- NIHR Biomedical Research Centre, Oxford, United Kingdom
| | - Barbara Gärtner
- Institut für Medizinische Mikrobiologie und Hygiene, Universität des Saarlands, Homburg, Germany
| | - Paul Schnitzler
- Center for Infectious Diseases, Virology, University Hospital of Heidelberg, Heidelberg, Germany
| | - Adrian Hill
- The Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Graham Taylor
- Molecular Diagnostic Unit, Imperial College Healthcare NHS Trust, London, United Kingdom
| | - Maria A. Demontis
- Molecular Diagnostic Unit, Imperial College Healthcare NHS Trust, London, United Kingdom
| | - Edward Guy
- Toxoplasma Reference Unit, Public Health Wales Microbiology, Swansea, United Kingdom
| | - Stephen J. Hadfield
- Toxoplasma Reference Unit, Public Health Wales Microbiology, Swansea, United Kingdom
| | | | - Naomi Allen
- UK Biobank, Stockport, United Kingdom
- Nuffield Department of Population Health, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Michael Pawlita
- Molecular Diagnostics of Oncogenic Infections Division, Infection, Inflammation and Cancer Research Program, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Tim Waterboer
- Infections and Cancer Epidemiology, Infection, Inflammation and Cancer Research Program, German Cancer Research Center (DKFZ), Heidelberg, Germany
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3
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Anupam R, Doueiri R, Green PL. The need to accessorize: molecular roles of HTLV-1 p30 and HTLV-2 p28 accessory proteins in the viral life cycle. Front Microbiol 2013; 4:275. [PMID: 24062732 PMCID: PMC3774995 DOI: 10.3389/fmicb.2013.00275] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 08/24/2013] [Indexed: 11/25/2022] Open
Abstract
Extensive studies of human T-cell leukemia virus (HTLV)-1 and HTLV-2 over the last three decades have provided detailed knowledge on viral transformation, host–viral interactions and pathogenesis. HTLV-1 is the etiological agent of adult T cell leukemia and multiple neurodegenerative and inflammatory diseases while HTLV-2 disease association remains elusive, with few infected individuals displaying neurodegenerative diseases similar to HTLV-1. The HTLV group of oncoretroviruses has a genome that encodes structural and enzymatic proteins Gag, Pro, and Env, regulatory proteins Tax and Rex, and several accessory proteins from the pX region. Of these proteins, HTLV-1 p30 and HTLV-2 p28 are encoded by the open reading frame II of the pX region. Like most other accessory proteins, p30 and p28 are dispensable for in vitro viral replication and transformation but are required for efficient viral replication and persistence in vivo. Both p30 and p28 regulate viral gene expression at the post-transcriptional level whereas p30 can also function at the transcriptional level. Recently, several reports have implicated p30 and p28 in multiple cellular processes, which provide novel insight into HTLV spread and survival and ultimately pathogenesis. In this review we summarize and compare what is known about p30 and p28, highlighting their roles in viral replication and viral pathogenesis.
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Affiliation(s)
- Rajaneesh Anupam
- Center for Retrovirus Research, The Ohio State University Columbus, OH, USA ; Department of Veterinary Biosciences, The Ohio State University Columbus, OH, USA
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Quantitative differences in HTLV-I antibody responses: classification and relative risk assessment for asymptomatic carriers and ATL and HAM/TSP patients from Jamaica. Blood 2012; 119:2829-36. [PMID: 22318200 DOI: 10.1182/blood-2011-11-390807] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Adult T-cell leukemia (ATL) and human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) are known to be caused by HTLV-I infection. However, current methods used to determine HTLV-I infection do not differentiate between HTLV-I asymptomatic carriers (ACs) and ATL and HAM/TSP patients. Using the luciferase immunoprecipitation system, a highly sensitive, quantitative technology that can efficiently detect HTLV-I Ab responses, we examined Ab responses for HTLV-I in serum/plasma samples from 439 subjects in Jamaica, including HTLV-I-seronegative donors, ACs, and ATL and HAM/TSP patients. The Ab responses of HTLV-I-infected subjects differed significantly from those of seronegative donors for all 3 immunodominant proteins, Gag, Env, and Tax. HAM/TSP patients had significantly higher Ab responses for Gag and Env compared with ACs, and Ab responses for all 3 Ags were higher in HAM/TSP patients than in ATL patients. Moreover, immunoreactivities for HTLV-I Ags as determined by the luciferase immunoprecipitation system could distinguish HAM/TSP patients from ACs at a true-positive rate of 85.42% and from ATL patients at a true-positive rate of 75.00%, and modeled in conjunction with subject information to distinguish HAM/TSP patients from ACs (odds ratio = 14.12) and from ATL patients (odds ratio = 7.00). The relative risk assessment resulting from these significant differences between Ab responses in HTLV-I-infected groups may be a useful diagnostic tool in the future.
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Lairmore MD, Anupam R, Bowden N, Haines R, Haynes RAH, Ratner L, Green PL. Molecular determinants of human T-lymphotropic virus type 1 transmission and spread. Viruses 2011; 3:1131-65. [PMID: 21994774 PMCID: PMC3185783 DOI: 10.3390/v3071131] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 07/01/2011] [Accepted: 07/02/2011] [Indexed: 01/23/2023] Open
Abstract
Human T-lymphotrophic virus type-1 (HTLV-1) infects approximately 15 to 20 million people worldwide, with endemic areas in Japan, the Caribbean, and Africa. The virus is spread through contact with bodily fluids containing infected cells, most often from mother to child through breast milk or via blood transfusion. After prolonged latency periods, approximately 3 to 5% of HTLV-1 infected individuals will develop either adult T-cell leukemia/lymphoma (ATL), or other lymphocyte-mediated disorders such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The genome of this complex retrovirus contains typical gag, pol, and env genes, but also unique nonstructural proteins encoded from the pX region. These nonstructural genes encode the Tax and Rex regulatory proteins, as well as novel proteins essential for viral spread in vivo such as, p30, p12, p13 and the antisense encoded HBZ. While progress has been made in the understanding of viral determinants of cell transformation and host immune responses, host and viral determinants of HTLV-1 transmission and spread during the early phases of infection are unclear. Improvements in the molecular tools to test these viral determinants in cellular and animal models have provided new insights into the early events of HTLV-1 infection. This review will focus on studies that test HTLV-1 determinants in context to full length infectious clones of the virus providing insights into the mechanisms of transmission and spread of HTLV-1.
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Affiliation(s)
- Michael D. Lairmore
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-614-292-9203; Fax: +1-614-292-6473
| | - Rajaneesh Anupam
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Nadine Bowden
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Robyn Haines
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Rashade A. H. Haynes
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
| | - Lee Ratner
- Department of Medicine, Pathology, and Molecular Microbiology, Division of Biology and Biological Sciences, Washington University School of Medicine, Campus Box 8069, 660 S. Euclid Ave., St. Louis, MO 63110, USA; E-Mail: (L.R.)
| | - Patrick L. Green
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA; E-Mails: (R.A.); (N.B.); (R.H.); (R.A.H.H.); (P.L.G.)
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
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Orf-I and orf-II-encoded proteins in HTLV-1 infection and persistence. Viruses 2011; 3:861-85. [PMID: 21994758 PMCID: PMC3185781 DOI: 10.3390/v3060861] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 05/25/2011] [Accepted: 05/26/2011] [Indexed: 01/10/2023] Open
Abstract
The 3′ end of the human T-cell leukemia/lymphoma virus type-1 (HTLV-1) genome contains four overlapping open reading frames (ORF) that encode regulatory proteins. Here, we review current knowledge of HTLV-1 orf-I and orf-II protein products. Singly spliced mRNA from orf-I encodes p12, which can be proteolytically cleaved to generate p8, while differential splicing of mRNA from orf-II results in production of p13 and p30. These proteins have been demonstrated to modulate transcription, apoptosis, host cell activation and proliferation, virus infectivity and transmission, and host immune responses. Though these proteins are not essential for virus replication in vitro, p8, p12, p13, and p30 have an important role in the establishment and maintenance of HTLV-1 infection in vivo.
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Anupam R, Datta A, Kesic M, Green-Church K, Shkriabai N, Kvaratskhelia M, Lairmore MD. Human T-lymphotropic virus type 1 p30 interacts with REGgamma and modulates ATM (ataxia telangiectasia mutated) to promote cell survival. J Biol Chem 2011; 286:7661-8. [PMID: 21216954 DOI: 10.1074/jbc.m110.176354] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) is a causative agent of adult T cell leukemia/lymphoma and a variety of inflammatory disorders. HTLV-1 encodes a nuclear localizing protein, p30, that selectively alters viral and cellular gene expression, activates G(2)-M cell cycle checkpoints, and is essential for viral spread. Here, we used immunoprecipitation and affinity pulldown of ectopically expressed p30 coupled with mass spectrometry to identify cellular binding partners of p30. Our data indicate that p30 specifically binds to cellular ATM (ataxia telangiectasia mutated) and REGγ (a nuclear 20 S proteasome activator). Under conditions of genotoxic stress, p30 expression was associated with reduced levels of ATM and increased cell survival. Knockdown or overexpression of REGγ paralleled p30 expression, suggesting an unexpected enhancement of p30 expression in the presence of REGγ. Finally, size exclusion chromatography revealed the presence of p30 in a high molecular mass complex along with ATM and REGγ. On the basis of our findings, we propose that HTLV-1 p30 interacts with ATM and REGγ to increase viral spread by facilitating cell survival.
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Affiliation(s)
- Rajaneesh Anupam
- Center for Retrovirus Research, Ohio State University, Columbus, Ohio 43210, USA
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8
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Chen CY, Ping YH, Lee HC, Chen KH, Lee YM, Chan YJ, Lien TC, Jap TS, Lin CH, Kao LS, Chen YMA. Open reading frame 8a of the human severe acute respiratory syndrome coronavirus not only promotes viral replication but also induces apoptosis. J Infect Dis 2007; 196:405-15. [PMID: 17597455 PMCID: PMC7204190 DOI: 10.1086/519166] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Accepted: 01/23/2007] [Indexed: 01/20/2023] Open
Abstract
Background. A unique genomic difference between human and civet severe acute respiratory syndrome coronaviruses (SARS-CoVs) is that the former has a deletion of 29 nucleotides from open reading frame (orf) 8d that results in the generation of orf8a and orf8b. The objectives of the present study were to analyze antibody reactivity to ORF8a in patients with SARS and to elucidate the function of ORF8a. Methods. Western-blot and immunofluorescent antibody assays were used to detect anti-ORF8a antibody. SARS-CoV HKU39849 was used to infect stable clones expressing ORF8a and cells transfected with small interfering RNA (siRNA). The virus loads (VLs) and cytopathic effects (CPEs) were recorded. Confocal microscopy and several mitochondria-related tests were used to study the function of ORF8a. Results. Two (5.4%) of 37 patients with SARS had anti-ORF8a antibodies. The VLs in the stable clones expressing ORF8a were significantly higher than those in control subjects 5 days after infection. siRNA against orf8a significantly reduced VLs and interrupted the CPE. ORF8a was found to be localized in mitochondria, and overexpression resulted in increases in mitochondrial transmembrane potential, reactive oxygen species production, caspase 3 activity, and cellular apoptosis. Conclusions. ORF8a not only enhances viral replication but also induces apoptosis through a mitochondria-dependent pathway.
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Affiliation(s)
- Chia-Yen Chen
- Istitute of Public Health, Taipei, Taiwan, Republic of China
- AIDS Prevention and Research Center, Taipei, Taiwan, Republic of China
| | - Yueh-Hsin Ping
- Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Hsin-Chen Lee
- Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Kuan-Hsuan Chen
- AIDS Prevention and Research Center, Taipei, Taiwan, Republic of China
| | - Yuan-Ming Lee
- Istitute of Public Health, Taipei, Taiwan, Republic of China
- Division of Clinical Virology, Department of Pathology and Laboratory Medicine, Taipei, Taiwan, Republic of China
| | - Yu-Juin Chan
- Division of Clinical Virology, Department of Pathology and Laboratory Medicine, Taipei, Taiwan, Republic of China
| | - Te-Cheng Lien
- Department of Respiratory Therapy, Taipei, Taiwan, Republic of China
| | - Tjin-Shing Jap
- Section of Biochemistry, Department of Pathology and Laboratory Medicine, Veterans General Hospital, Taipei, Taiwan, Republic of China
| | - Chi-Hung Lin
- Institute of Microbiology and Immunology, Taipei, Taiwan, Republic of China
| | - Lung-Sen Kao
- Faculty of Life Science, National Yang-Ming University, Taipei, Taiwan, Republic of China
| | - Yi-Ming Arthur Chen
- Istitute of Public Health, Taipei, Taiwan, Republic of China
- AIDS Prevention and Research Center, Taipei, Taiwan, Republic of China
- Reprints or correspondence: Prof. Yi-Ming A Chen, AIDS Prevention and Research Center, National Yang-Ming University, Li-Noun Street, Section 2, Taipei, Taiwan 112 ()
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Chevalier SA, Meertens L, Pise-Masison C, Calattini S, Park H, Alhaj AA, Zhou M, Gessain A, Kashanchi F, Brady JN, Mahieux R. The tax protein from the primate T-cell lymphotropic virus type 3 is expressed in vivo and is functionally related to HTLV-1 Tax rather than HTLV-2 Tax. Oncogene 2006; 25:4470-82. [PMID: 16532031 DOI: 10.1038/sj.onc.1209472] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human T-cell leukemia virus and simian T-cell leukemia virus (STLV) form the primate T-cell lymphotropic viruses group. Human T-cell leukemia virus type 1 and type 2 (HTLV-1 and HTLV-2) encode the Tax viral transactivator (Tax1 and Tax2, respectively). Tax1 possesses an oncogenic potential and is responsible for cell transformation both in vivo and in vitro. We and others have recently discovered the existence of human T-cell lymphotropic virus type 3. However, there is currently no evidence for the presence of a Tax protein in HTLV-3-infected individuals. We show that the serum of an HTLV-3 asymptomatic carrier and the sera of two STLV-3-infected monkeys contain specific anti-Tax3 antibodies. We also show that tax3 mRNA is present in the PBMCs obtained from an STLV-3-infected monkey, demonstrating that Tax3 is expressed in vivo. We further demonstrate that Tax3 intracellular localization is very similar to that of Tax1 and that Tax3 binds to both CBP and p300 coactivators. Using purified Tax3, we show that the protein increases transcription from a 4TxRE G-free cassette plasmid in an in vitro transcription assay. In all cell types tested, including transiently transfected lymphocytes, Tax3 activates its own promoter STLV-3 long terminal repeat (LTR), which contains only two Tax Responsive Elements (TREs), and activates also HTLV-1 and HTLV-2 LTRs. In addition, Tax3 also activates the NF-kappaB pathway. We also show that Tax3 possesses a PDZ-binding sequence at its C-terminal end. Our results demonstrate that Tax3 is a transactivator, and that its properties are more similar to that of Tax1, rather than of Tax2. This suggests the possible occurrence of lymphoproliferative disorders among HTLV-3-infected populations.
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Affiliation(s)
- S A Chevalier
- Unité d'Epidémiologie et Physiopathologie des Virus Oncogènes, Institut Pasteur, Paris, France
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D’Agostino DM, Silic-Benussi M, Hiraragi H, Lairmore MD, Ciminale V. The human T-cell leukemia virus type 1 p13II protein: effects on mitochondrial function and cell growth. Cell Death Differ 2005; 12 Suppl 1:905-15. [PMID: 15761473 PMCID: PMC3057663 DOI: 10.1038/sj.cdd.4401576] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
p13(II) of human T-cell leukemia virus type 1 (HTLV-1) is an 87-amino-acid protein that is targeted to the inner mitochondrial membrane. p13(II) alters mitochondrial membrane permeability, producing a rapid, membrane potential-dependent influx of K(+). These changes result in increased mitochondrial matrix volume and fragmentation and may lead to depolarization and alterations in mitochondrial Ca(2+) uptake/retention capacity. At the cellular level, p13(II) has been found to interfere with cell proliferation and transformation and to promote apoptosis induced by ceramide and Fas ligand. Assays carried out in T cells (the major targets of HTLV-1 infection in vivo) demonstrate that p13(II)-mediated sensitization to Fas ligand-induced apoptosis can be blocked by an inhibitor of Ras farnesylation, thus implicating Ras signaling as a downstream target of p13(II) function.
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Affiliation(s)
- DM D’Agostino
- Department of Oncology and Surgical Sciences, University of Padova, Padova 35128, Italy
| | - M Silic-Benussi
- Department of Oncology and Surgical Sciences, University of Padova, Padova 35128, Italy
| | - H Hiraragi
- Center for Retrovirus Research and Department of Veterinary Biosciences, College of Veterinary Medicine, Columbus, OH 43210, USA
| | - MD Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, College of Veterinary Medicine, Columbus, OH 43210, USA
- Comprehensive Cancer Center and Richard J. Solove Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - V Ciminale
- Department of Oncology and Surgical Sciences, University of Padova, Padova 35128, Italy
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Green PL. HTLV-1 p30II: selective repressor of gene expression. Retrovirology 2004; 1:40. [PMID: 15563375 PMCID: PMC543446 DOI: 10.1186/1742-4690-1-40] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2004] [Accepted: 11/24/2004] [Indexed: 11/11/2022] Open
Abstract
Human T-lymphotropic virus type-1 (HTLV-1) is a complex retrovirus that causes adult T-cell leukemia/lymphoma (ATL) and is implicated in a variety of lymphocyte-mediated disorders. HTLV-1 pX ORF II encodes two proteins, p13II and p30II whose roles are beginning to be defined in the virus life cycle. Previous studies indicate the importance of these viral proteins in the ability of the virus to maintain viral loads and persist in an animal model of HTLV-1 infection. Intriguing new studies indicate that p30II is a multifunctional regulator that differentially modulates CREB and Tax-responsive element-mediated transcription through its interaction with CREB-binding protein (CBP)/p300 and specifically binds and represses tax/rex mRNA nuclear export. A new study characterized the role of p30II in regulation of cellular gene expression using comprehensive human gene arrays. Interestingly, p30II is an overall repressor of cellular gene expression, while selectively favoring the expression of regulatory gene pathways important to T lymphocytes. These new findings suggest that HTLV-1, which is associated with lymphoproliferative diseases, uses p30II to selectively repress cellular and viral gene expression to favor the survival of cellular targets ultimately resulting in leukemogenesis.
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Affiliation(s)
- Patrick L Green
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA.
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12
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Michael B, Nair AM, Hiraragi H, Shen L, Feuer G, Boris-Lawrie K, Lairmore MD. Human T lymphotropic virus type-1 p30II alters cellular gene expression to selectively enhance signaling pathways that activate T lymphocytes. Retrovirology 2004; 1:39. [PMID: 15560845 PMCID: PMC538277 DOI: 10.1186/1742-4690-1-39] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2004] [Accepted: 11/23/2004] [Indexed: 11/13/2022] Open
Abstract
Background Human T-lymphotropic virus type-1 (HTLV-1) is a deltaretrovirus that causes adult T-cell leukemia/lymphoma and is implicated in a variety of lymphocyte-mediated disorders. HTLV-1 contains both regulatory and accessory genes in four pX open reading frames. pX ORF-II encodes two proteins, p13II and p30II, which are incompletely defined in the virus life cycle or HTLV-1 pathogenesis. Proviral clones of the virus with pX ORF-II mutations diminish the ability of the virus to maintain viral loads in vivo. Exogenous expression of p30II differentially modulates CREB and Tax-responsive element-mediated transcription through its interaction with CREB-binding protein/p300 and represses tax/rex RNA nuclear export. Results Herein, we further characterized the role of p30II in regulation of cellular gene expression, using stable p30II expression system employing lentiviral vectors to test cellular gene expression with Affymetrix U133A arrays, representing ~33,000 human genes. Reporter assays in Jurkat T cells and RT-PCR in Jurkat and primary CD4+ T-lymphocytes were used to confirm selected gene expression patterns. Our data reveals alterations of interrelated pathways of cell proliferation, T-cell signaling, apoptosis and cell cycle in p30II expressing Jurkat T cells. In all categories, p30II appeared to be an overall repressor of cellular gene expression, while selectively increasing the expression of certain key regulatory genes. Conclusions We are the first to demonstrate that p30II, while repressing the expression of many genes, selectively activates key gene pathways involved in T-cell signaling/activation. Collectively, our data suggests that this complex retrovirus, associated with lymphoproliferative diseases, relies upon accessory gene products to modify cellular environment to promote clonal expansion of the virus genome and thus maintain proviral loads in vivo.
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Affiliation(s)
- Bindhu Michael
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Safety Assessment, Merck &Co., Inc. WP45-224, West Point PA 19486, USA
| | - Amrithraj M Nair
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Safety Assessment, Merck &Co., Inc. WP45-224, West Point PA 19486, USA
| | - Hajime Hiraragi
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
| | - Lei Shen
- Department of Statistics, College of Mathematical and Physical Sciences, The Ohio State University, Columbus, Ohio 43210, USA
| | - Gerold Feuer
- Department of Microbiology and Immunology, State University of New York Upstate Medical University, Syracuse, New York 13210, USA
| | - Kathleen Boris-Lawrie
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio 43210, USA
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
| | - Michael D Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio 43210, USA
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210, USA
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Michael B, Nair A, Lairmore MD. Role of accessory proteins of HTLV-1 in viral replication, T cell activation, and cellular gene expression. FRONT BIOSCI-LANDMRK 2004; 9:2556-76. [PMID: 15358581 PMCID: PMC2829751 DOI: 10.2741/1417] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1), causes adult T cell leukemia/lymphoma (ATLL), and initiates a variety of immune mediated disorders. The viral genome encodes common structural and enzymatic proteins characteristic of all retroviruses and utilizes alternative splicing and alternate codon usage to make several regulatory and accessory proteins encoded in the pX region (pX ORF I to IV). Recent studies indicate that the accessory proteins p12I, p27I, p13II, and p30II, encoded by pX ORF I and II, contribute to viral replication and the ability of the virus to maintain typical in vivo expression levels. Proviral clones that are mutated in either pX ORF I or II, while fully competent in cell culture, are severely limited in their replicative capacity in a rabbit model. These HTLV-1 accessory proteins are critical for establishment of viral infectivity, enhance T-lymphocyte activation and potentially alter gene transcription and mitochondrial function. HTLV-1 pX ORF I expression is critical to the viral infectivity in resting primary lymphocytes suggesting a role for the calcineurin-binding protein p12I in lymphocyte activation. The endoplasmic reticulum and cis-Golgi localizing p12I activates NFAT, a key T cell transcription factor, through calcium-mediated signaling pathways and may lower the threshold of lymphocyte activation via the JAK/STAT pathway. In contrast p30II localizes to the nucleus and represses viral promoter activity, but may regulate cellular gene expression through p300/CBP or related co-activators of transcription. The mitochondrial localizing p13II induces morphologic changes in the organelle and may influence energy metabolism infected cells. Future studies of the molecular details HTLV-1 "accessory" proteins interactions will provide important new directions for investigations of HTLV-1 and related viruses associated with lymphoproliferative diseases. Thus, the accessory proteins of HTLV-1, once thought to be dispensable for viral replication, have proven to be directly involved in viral spread in vivo and represent potential targets for therapeutic intervention against HTLV-1 infection and disease.
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Affiliation(s)
- Bindhu Michael
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
| | - Amithraj Nair
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
| | - Michael D. Lairmore
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210
- Department of Molecular Virology, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio 43210
- Comprehensive Cancer Center, The Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
- Corresponding Author: Dr. Michael D. Lairmore, The Ohio State University, Department of Veterinary Biosciences, 1925 Coffey Road, Columbus, OH 43210-1093, Phone: (614) 292-4489. Fax: (614) 292-6473.
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Silverman LR, Phipps AJ, Montgomery A, Ratner L, Lairmore MD. Human T-cell lymphotropic virus type 1 open reading frame II-encoded p30II is required for in vivo replication: evidence of in vivo reversion. J Virol 2004; 78:3837-45. [PMID: 15047799 PMCID: PMC374265 DOI: 10.1128/jvi.78.8.3837-3845.2004] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) causes adult T-cell leukemia/lymphoma and exhibits high genetic stability in vivo. HTLV-1 contains four open reading frames (ORFs) in its pX region. ORF II encodes two proteins, p30(II) and p13(II), both of which are incompletely characterized. p30(II) localizes to the nucleus or nucleolus and has distant homology to the transcription factors Oct-1, Pit-1, and POU-M1. In vitro studies have demonstrated that at low concentrations, p30(II) differentially regulates cellular and viral promoters through an interaction with CREB binding protein/p300. To determine the in vivo significance of p30(II), we inoculated rabbits with cell lines expressing either a wild-type clone of HTLV-1 (ACH.1) or a clone containing a mutation in ORF II, which eliminated wild-type p30(II) expression (ACH.30.1). ACH.1-inoculated rabbits maintained higher HTLV-1-specific antibody titers than ACH.30.1-inoculated rabbits, and all ACH.1-inoculated rabbits were seropositive for HTLV-1, whereas only two of six ACH.30.1-inoculated rabbits were seropositive. Provirus could be consistently PCR amplified from peripheral blood mononuclear cell (PBMC) DNA in all ACH.1-inoculated rabbits but in only three of six ACH.30.1-inoculated rabbits. Quantitative competitive PCR indicated higher PBMC proviral loads in ACH.1-inoculated rabbits. Interestingly, sequencing of ORF II from PBMC of provirus-positive ACH.30.1-inoculated rabbits revealed a reversion to wild-type sequence with evidence of early coexistence of mutant and wild-type sequence. Our data provide evidence that HTLV-1 must maintain its key accessory genes to survive in vivo and that in vivo pressures select for maintenance of wild-type ORF II gene products during the early course of infection.
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Affiliation(s)
- Lee R Silverman
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
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15
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Franchini G, Nicot C, Johnson JM. Seizing of T Cells by Human T-Cell Leukemia⧸Lymphoma Virus Type 1. Adv Cancer Res 2003; 89:69-132. [PMID: 14587871 DOI: 10.1016/s0065-230x(03)01003-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) causes neoplastic transformation of human T-cells in a small number of infected individuals several years from infection. Several viral proteins act in concert to increase the responsiveness of T-cells to extracellular stimulation, modulate proapoptotic and antiapoptotic gene signals, enhance T-cell survival, and avoid immune recognition of the infected T-cells. The virus promotes T-cell proliferation by usurping several signaling pathways central to immune T-cell function. Viral proteins modulate the downstream effects of antigen stimulation and receptor-ligand interaction, suggesting that extracellular signals are important for HTLV-1 oncogenesis. Environmental factors such as chronic antigen stimulation are therefore important, as also suggested by epidemiological data. The ability of a given individual to respond to specific antigens is determined genetically. Thus, genetic and environmental factors, together with the virus, contribute to disease development. As in the case of other virus-associated cancers, HTLV-1-induced leukemia/lymphoma can be prevented by avoiding viral infection or by intervention during the asymptomatic phase with approaches able to interrupt the vicious cycle of virus-induced proliferation of a subset of T-cells. This review focuses on current knowledge of the mechanisms regulating HTLV-1 replication and the T-cell pathways that are usurped by viral proteins to induce and maintain clonal proliferation of infected T-cells in vitro. The relevance of these laboratory findings will be related to clonal T-cell proliferation and adult T-cell leukemia/lymphoma development in vivo.
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Affiliation(s)
- Genoveffa Franchini
- National Cancer Institute, Basic Research Laboratory, Bethesda, Maryland 20892, USA
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16
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Albrecht B, Lairmore MD. Critical role of human T-lymphotropic virus type 1 accessory proteins in viral replication and pathogenesis. Microbiol Mol Biol Rev 2002; 66:396-406, table of contents. [PMID: 12208996 PMCID: PMC120794 DOI: 10.1128/mmbr.66.3.396-406.2002] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) infection is associated with a diverse range of lymphoproliferative and neurodegenerative diseases, yet pathogenic mechanisms induced by the virus remain obscure. This complex retrovirus contains typical structural and enzymatic genes but also unique regulatory and accessory genes in four open reading frames (ORFs) of the pX region of the viral genome (pX ORFs I to IV). The regulatory proteins encoded by pX ORFs III and IV, Tax and Rex, respectively, have been extensively characterized. In contrast the contribution of the four accessory proteins p12(I), p27(I), p13(II), and p30(II), encoded by pX ORFs I and II, to viral replication and pathogenesis remained unclear. Proviral clones that are mutated in either pX ORF I or II, while fully competent in cell culture, are severely limited in their replicative capacity in a rabbit model. Emerging evidence indicates that the HTLV-1 accessory proteins are critical for establishment of viral infectivity, enhance T-lymphocyte activation, and potentially alter gene transcription and mitochondrial function. HTLV-1 pX ORF I expression is critical to the viral infectivity in resting primary lymphocytes, suggesting a role for p12(I) in lymphocyte activation. The endoplasmic reticulum and cis-Golgi localizing p12(I), encoded from pX ORF I, activates NFAT, a key T-cell transcription factor, through calcium-mediated signaling pathways and may lower the threshold of lymphocyte activation via the JAK/STAT pathway. In contrast p30(II) localizes to the nucleus and represses viral promoter activity, but may regulate cellular gene expression through p300/CBP or related coactivators of transcription. p13(II) targets mitochondrial proteins, where it alters the organelle morphology and may influence energy metabolism. Collectively, studies of the molecular functions of the HTLV-1 accessory proteins provide insight into strategies used by retroviruses that are associated with lymphoproliferative diseases.
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Affiliation(s)
- Björn Albrecht
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
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17
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Albrecht B, D'Souza CD, Ding W, Tridandapani S, Coggeshall KM, Lairmore MD. Activation of nuclear factor of activated T cells by human T-lymphotropic virus type 1 accessory protein p12(I). J Virol 2002; 76:3493-501. [PMID: 11884573 PMCID: PMC136046 DOI: 10.1128/jvi.76.7.3493-3501.2002] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) is the agent of an aggressive malignancy of CD4(+) T lymphocytes, called adult T-cell lymphoma/leukemia, and is associated with numerous immune-mediated diseases. To establish infection, HTLV-1 must activate targeted T cells during early stages of infection. We recently demonstrated that the HTLV-1 accessory protein p12(I) is critical for persistent infection in vivo and for viral infectivity in quiescent primary lymphocytes, suggesting a role for p12(I) in lymphocyte activation. To test whether p12(I) modulates signaling pathways required for T-lymphocyte activation, we examined AP-1-, NF-kappaB-, and nuclear factor of activated T cells (NFAT)-driven reporter gene activity in p12(I)-expressing Jurkat T cells compared to vector-transfected control cells. HTLV-1 p12(I) specifically induced NFAT-mediated transcription approximately 20-fold in synergy with the Ras/mitogen-activated protein kinase pathway, but did not influence AP-1- or NF-kappaB-dependent gene expression. Inhibition of calcium-dependent signals by cyclosporin A, BAPTA-AM [glycine, N,N'-1,2-ethanediylbis(oxy-2,1-phenylene)-bis-N-2-(acetyloxy)methoxy-2-oxoethyl]-[bis(acetyloxy)methyl ester], and a dominant negative mutant of NFAT2 abolished the p12(I)-mediated activation of NFAT-dependent transcription. In contrast, inhibition of phospholipase C-gamma and LAT (linker for activation of T cells) did not affect p12(I)-induced NFAT activity. Importantly, p12(I) functionally substituted for thapsigargin, which selectively depletes intracellular calcium stores. Our data are the first to demonstrate a role for HTLV-1 p12(I) in calcium-dependent activation of NFAT-mediated transcription in lymphoid cells. We propose a novel mechanism by which HTLV-1, a virus associated with lymphoproliferative disease, dysregulates common T-cell activation pathways critical for the virus to establish persistent infection.
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Affiliation(s)
- Björn Albrecht
- Center for Retrovirus Research and Department of Veterinary Biosciences, College of Medicine and Public Health, The Ohio State University, Columbus, Ohio 43210, USA
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18
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Lefèbvre L, Vanderplasschen A, Ciminale V, Heremans H, Dangoisse O, Jauniaux JC, Toussaint JF, Zelnik V, Burny A, Kettmann R, Willems L. Oncoviral bovine leukemia virus G4 and human T-cell leukemia virus type 1 p13(II) accessory proteins interact with farnesyl pyrophosphate synthetase. J Virol 2002; 76:1400-14. [PMID: 11773414 PMCID: PMC135811 DOI: 10.1128/jvi.76.3.1400-1414.2002] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
G4 and p13(II) are accessory proteins encoded by the X region of bovine leukemia virus and human T-cell leukemia virus type 1 (HTLV-1), respectively. Disruption of the G4 and p13(II) open reading frames interferes with viral spread in animal model systems, indicating that the corresponding proteins play a key role in viral replication. In addition, G4 is oncogenic in primary cell cultures and is absolutely required for efficient onset of leukemogenesis in sheep. To gain insight into the function of these proteins, we utilized the yeast two-hybrid system to identify protein partners of G4. Results revealed that G4 interacts with farnesyl pyrophosphate synthetase (FPPS), a protein involved in the mevalonate/squalene pathway and in synthesis of FPP, a substrate required for prenylation of Ras. The specificity of the interaction was verified by glutathione S-transferase (GST) pull-down assays and by coimmunoprecipitation experiments. Furthermore, confocal microscopy showed that the subcellular localization of G4 was profoundly affected by FPPS. The G4 protein itself was not prenylated, at least in rabbit reticulocyte lysate-based assays. The domain of G4 required for binding to FPPS was restricted to an amphipathic alpha-helix rich in arginine residues. Subtle mutation of this alpha-helix abrogated G4 oncogenic potential in vitro, providing a biological relevance for FPPS-G4 complex formation in cells. Finally, HTLV-1 p13(II) was also found to specifically interact with FPPS (in yeast as well as in GST pull-down assays) and to colocalize with G4 in mitochondria, suggesting a functional analogy between these oncoviral accessory proteins. Identification of FPPS as a molecular partner for p13(II) and G4 accessory proteins opens new prospects for treatment of retrovirus-induced leukemia.
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19
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D'Agostino DM, Zotti L, Ferro T, Cavallori I, Silic-Benussi M, Chieco-Bianchi L, Ciminale V. Expression and functional properties of proteins encoded in the x-II ORF of HTLV-I. Virus Res 2001; 78:35-43. [PMID: 11520578 DOI: 10.1016/s0168-1702(01)00282-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
With the aim of identifying viral proteins that contribute to the distinctive properties of HTLV-I biology and pathogenicity, several laboratories have investigated the coding potential of the X region of the genome, which includes five partially overlapping open reading frames (ORFs). We and others have shown that, in addition to the essential regulatory proteins Rex and Tax, a number of accessory proteins encoded in the X region can be produced by alternative splicing and multicistronic translation. One X region ORF, termed X-II, produces two protein isoforms named Tof/p30II and p13II, which are expressed from a doubly- and singly-spliced mRNA, respectively. Initial functional analyses demonstrated that Tof/p30II is a nucleolar/nuclear protein that possesses a region capable of binding to RNA, and p13II is a mitochondrial protein that alters the morphology and function of this organelle. Together with data from other laboratories demonstrating the production of antibodies and CTL against x-II ORF products in HTLV-I infected subjects and the requirement of this ORF for efficient viral replication in vivo, these findings suggest that further characterization of Tof/p30II and p13II will yield insight into remaining undefined aspects of HTLV-I pathogenicity and replication.
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Affiliation(s)
- D M D'Agostino
- Department of Oncology and Surgical Sciences, University of Padva, Via Gattamelata 64, 35128, Padua, Italy
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20
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Albrecht B, Collins ND, Burniston MT, Nisbet JW, Ratner L, Green PL, Lairmore MD. Human T-lymphotropic virus type 1 open reading frame I p12(I) is required for efficient viral infectivity in primary lymphocytes. J Virol 2000; 74:9828-35. [PMID: 11024109 PMCID: PMC102019 DOI: 10.1128/jvi.74.21.9828-9835.2000] [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] [Indexed: 01/29/2023] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) is a complex retrovirus encoding regulatory and accessory genes in four open reading frames (ORF I to IV) of the pX region. Emerging evidence indicates an important role for the pX ORF I-encoded accessory protein p12(I) in viral replication, but its contribution to viral pathogenesis remains to be defined. p12(I) is a conserved, membrane-associated protein containing four SH3-binding motifs (PXXP). Its interaction with the interleukin-2 (IL-2) receptor beta- and gamma-chains implies an involvement of p12(I) in intracellular signaling pathways. In addition, we have demonstrated that expression of pX ORF I p12(I) is essential for persistent infection in rabbits. In contrast, standard in vitro systems have thus far failed to demonstrate a contribution of p12(I) to viral infectivity and ultimately cellular transformation. In this study we developed multiple in vitro coculture assays to evaluate the role of p12(I) in viral infectivity in quiescent peripheral blood mononuclear cells to more accurately reflect the virus-cell interactions as they occur in vivo. Using these assays, we demonstrate a dramatic reduction in viral infectivity in quiescent T lymphocytes for a p12 mutant viral clone (ACH.p12) in comparison to the wild-type clone ACH. Moreover, addition of IL-2 and phytohemagglutinin during the infection completely rescued the ability of ACH.p12 to infect primary lymphocytes. When newly infected primary lymphocytes are used to passage virus, ACH.p12 also exhibited a reduced ability to productively infect activated lymphocytes. Our data are the first to demonstrate a functional role for pX ORF I in the infection of primary lymphocytes and suggest a role for p12(I) in activation of host cells during early stages of infection.
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Affiliation(s)
- B Albrecht
- Center for Retrovirus Research and Department of Veterinary Biosciences, Immunology and Medical Genetics, The Ohio State University, Columbus, Ohio 43210, USA
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21
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Pique C, Ureta-Vidal A, Gessain A, Chancerel B, Gout O, Tamouza R, Agis F, Dokhélar MC. Evidence for the chronic in vivo production of human T cell leukemia virus type I Rof and Tof proteins from cytotoxic T lymphocytes directed against viral peptides. J Exp Med 2000; 191:567-72. [PMID: 10662802 PMCID: PMC2195825 DOI: 10.1084/jem.191.3.567] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Human T cell leukemia virus type I (HTLV-I) is a persistent virus that causes adult T cell leukemia and tropical spastic paraparesis/HTLV-I-associated myelopathy. Studies on rabbits have shown that viral proteins encoded by the open reading frames pX-I and pX-II are required for the establishment of the persistent infection. To examine the in vivo production of these proteins in humans, we have investigated whether cytotoxic T lymphocytes isolated from HTLV-I-infected individuals recognized pX-I and pX-II peptides. CD8(+) T lymphocytes to pX-I and pX-II peptides were detected in HTLV-I-infected individuals, whatever their clinical status, and even in the absence of any antigenic restimulation. These findings indicate that the HTLV-I pX-I and pX-II proteins are chronically synthesized in vivo, and are targets of the natural immune response to the virus.
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Affiliation(s)
- C Pique
- Institut National de la Santé et de la Recherche Médicale, U332, Institut Cochin de Génétique Moléculaire, 75014 Paris, France.
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22
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Bartoe JT, Albrecht B, Collins ND, Robek MD, Ratner L, Green PL, Lairmore MD. Functional role of pX open reading frame II of human T-lymphotropic virus type 1 in maintenance of viral loads in vivo. J Virol 2000; 74:1094-100. [PMID: 10627519 PMCID: PMC111443 DOI: 10.1128/jvi.74.3.1094-1100.2000] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) causes adult T-cell leukemia/lymphoma and is associated with a variety of immune-mediated disorders. The role of four open reading frames (ORFs), located between env and the 3' long terminal repeat of HTLV-1, in mediating disease is not entirely clear. By differential splicing, ORF II encodes two proteins, p13(II) and p30(II), both of which have not been functionally defined. p13(II) localizes to mitochondria and may alter the configuration of the tubular network of this cellular organelle. p30(II) localizes to the nucleolus and shares homology with the transcription factors Oct-1 and -2, Pit-1, and POU-M1. Both p13(II) and p30(II) are dispensable for infection and immortalization of primary human and rabbit lymphocytes in vitro. To test the role of ORF II gene products in vivo, we inoculated rabbits with lethally irradiated cell lines expressing the wild-type molecular clone of HTLV-1 (ACH.1) or a clone containing selected mutations in ORF II (ACH.30/13.1). ACH.1-inoculated animals maintained higher HTLV-1-specific antibody titers than animals inoculated with ACH.30/13.1. Viral p19 antigen was transiently detected in ex vivo cultures of peripheral blood mononuclear cells (PBMC) from only two ACH.30/13.1-inoculated rabbits, while PBMC cultures from all ACH.1-inoculated rabbits routinely produced p19 antigen. In only three of six animals exposed to the ACH. p30(II)/p13(II) clone could provirus be consistently PCR amplified from extracted PBMC DNA and quantitative competitive PCR showed the proviral loads in PBMC from ACH.p30(II)/p13(II)-infected rabbits to be dramatically lower than the proviral loads in rabbits exposed to ACH. Our data indicate selected mutations in pX ORF II diminish the ability of HTLV-1 to maintain high viral loads in vivo and suggest an important function for p13(II) and p30(II) in viral pathogenesis.
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Affiliation(s)
- J T Bartoe
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210-1093, USA
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Ciminale V, Zotti L, D'Agostino DM, Ferro T, Casareto L, Franchini G, Bernardi P, Chieco-Bianchi L. Mitochondrial targeting of the p13II protein coded by the x-II ORF of human T-cell leukemia/lymphotropic virus type I (HTLV-I). Oncogene 1999; 18:4505-14. [PMID: 10442641 DOI: 10.1038/sj.onc.1203047] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The X region of the HTLV-I genome contains four major open reading frames (ORFs), two of which, termed x-I and x-II, are of still undefined biological significance. By indirect immunofluorescence and dual labeling with marker proteins, we demonstrate that p13II, an 87-amino acid protein coded by the x-II ORF, is selectively targeted to mitochondria. Mutational analysis revealed that mitochondrial targeting of p13II is directed by an atypical 10-amino acid signal sequence that is not cleaved upon import and is able to target the Green Fluorescent Protein to mitochondria. Expression of p13II results in specific alterations of mitochondrial morphology and distribution from a typical string-like, dispersed network to round-shaped clusters, suggesting that p13II might interfere with processes relying on an intact mitochondrial architecture. Functional studies of mitochondria with the cationic fluorochrome tetramethylrhodamine revealed that a subpopulation of the cells with p13II-positive mitochondria show a disruption in the mitochondrial inner membrane potential (Apsi), an early event observed in cells committed to apoptosis. Taken together, these results suggest novel virus-cell interactions that might be important in HTLV-I replication and/or pathogenicity.
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Affiliation(s)
- V Ciminale
- Department of Oncology and Surgical Sciences, University of Padova, Italy
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24
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Robek MD, Wong FH, Ratner L. Human T-cell leukemia virus type 1 pX-I and pX-II open reading frames are dispensable for the immortalization of primary lymphocytes. J Virol 1998; 72:4458-62. [PMID: 9557741 PMCID: PMC109681 DOI: 10.1128/jvi.72.5.4458-4462.1998] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) infects and transforms CD4+ T-lymphocytes both in vivo and in vitro. Although the Tax protein of HTLV-1 has been strongly implicated as a transforming agent, other virally encoded proteins may also play a role in the transformation process. In addition to the rex and tax genes, the pX region of the HTLV-1 genome contains two open reading frames (pX-I and pX-II) which encode the putative viral accessory proteins known as p12I, p30II, and p13II. Mutations in the ACH molecular clone of HTLV-1 that are predicted to abrogate the expression of p12I, p13II and p30II were constructed. These mutations had no effect on viral replication or the immortalization of primary lymphocytes. Although these proteins are dispensable for viral replication and immortalization in vitro, it remains possible that they alter infection in vivo.
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Affiliation(s)
- M D Robek
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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