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Khan KA, Marineau A, Doyon P, Acevedo M, Durette É, Gingras AC, Servant MJ. TRK-Fused Gene (TFG), a protein involved in protein secretion pathways, is an essential component of the antiviral innate immune response. PLoS Pathog 2021; 17:e1009111. [PMID: 33411856 PMCID: PMC7790228 DOI: 10.1371/journal.ppat.1009111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 10/30/2020] [Indexed: 12/15/2022] Open
Abstract
Antiviral innate immune response to RNA virus infection is supported by Pattern-Recognition Receptors (PRR) including RIG-I-Like Receptors (RLR), which lead to type I interferons (IFNs) and IFN-stimulated genes (ISG) production. Upon sensing of viral RNA, the E3 ubiquitin ligase TNF Receptor-Associated Factor-3 (TRAF3) is recruited along with its substrate TANK-Binding Kinase (TBK1), to MAVS-containing subcellular compartments, including mitochondria, peroxisomes, and the mitochondria-associated endoplasmic reticulum membrane (MAM). However, the regulation of such events remains largely unresolved. Here, we identify TRK-Fused Gene (TFG), a protein involved in the transport of newly synthesized proteins to the endomembrane system via the Coat Protein complex II (COPII) transport vesicles, as a new TRAF3-interacting protein allowing the efficient recruitment of TRAF3 to MAVS and TBK1 following Sendai virus (SeV) infection. Using siRNA and shRNA approaches, we show that TFG is required for virus-induced TBK1 activation resulting in C-terminal IRF3 phosphorylation and dimerization. We further show that the ability of the TRAF3-TFG complex to engage mTOR following SeV infection allows TBK1 to phosphorylate mTOR on serine 2159, a post-translational modification shown to promote mTORC1 signaling. We demonstrate that the activation of mTORC1 signaling during SeV infection plays a positive role in the expression of Viperin, IRF7 and IFN-induced proteins with tetratricopeptide repeats (IFITs) proteins, and that depleting TFG resulted in a compromised antiviral state. Our study, therefore, identifies TFG as an essential component of the RLR-dependent type I IFN antiviral response. Antiviral innate immune response is the first line of defence against the invading viruses through type I interferon (IFN) signaling. However, viruses have devised ways to target signaling molecules for aberrant IFN response and worsen the disease outcome. As such, deciphering the roles of new regulators of innate immunity could transform the antiviral treatment paradigm by introducing novel panviral therapeutics designed to reinforce antiviral host responses. This could be of great use in fighting recent outbreaks of severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome MERS-CoV, and the more recent SARS-CoV-2 causing the COVID-19 pandemic. However, aberrant activation of such pathways can lead to detrimental consequences, including autoimmune diseases. Regulation of type I IFN responses is thus of paramount importance. To prevent an uncontrolled response, signaling events happen in discrete subcellular compartments, therefore, distinguishing sites involved in recognition of pathogens and those permitting downstream signaling. Here, we show TFG as a new regulator of type I IFN response allowing the efficient organization of signaling molecules. TFG, thus, further substantiates the importance of the protein trafficking machinery in the regulation of optimal antiviral responses. Our findings have implications for both antiviral immunity and autoimmune diseases.
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Affiliation(s)
| | | | - Priscilla Doyon
- Faculty of Pharmacy, Université de Montréal, Montréal, Canada
| | - Mariana Acevedo
- Faculty of Pharmacy, Université de Montréal, Montréal, Canada
| | - Étienne Durette
- Faculty of Pharmacy, Université de Montréal, Montréal, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Marc J. Servant
- Faculty of Pharmacy, Université de Montréal, Montréal, Canada
- * E-mail:
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Hallam HJ, Lokugamage N, Ikegami T. Rescue of infectious Arumowot virus from cloned cDNA: Posttranslational degradation of Arumowot virus NSs protein in human cells. PLoS Negl Trop Dis 2019; 13:e0007904. [PMID: 31751340 PMCID: PMC6894884 DOI: 10.1371/journal.pntd.0007904] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 12/05/2019] [Accepted: 11/04/2019] [Indexed: 12/11/2022] Open
Abstract
Rift Valley fever (RVF) is a mosquito-borne zoonotic disease endemic to Africa and the Middle East, affecting both humans and ruminants. There are no licensed vaccines or antivirals available for humans, whereas research using RVF virus (RVFV) is strictly regulated in many countries with safety concerns. Nonpathogenic Arumowot virus (AMTV), a mosquito-borne phlebovirus in Africa, is likely useful for the screening of broad-acting antiviral candidates for phleboviruses including RVFV, as well as a potential vaccine vector for RVF. In this study, we aimed to generate T7 RNA polymerase-driven reverse genetics system for AMTV. We hypothesized that recombinant AMTV (rAMTV) is viable, and AMTV NSs protein is dispensable for efficient replication of rAMTV in type-I interferon (IFN)-incompetent cells, whereas AMTV NSs proteins support robust viral replication in type-I IFN-competent cells. The study demonstrated the rescue of rAMTV and that lacking the NSs gene (rAMTVΔNSs), that expressing green fluorescent protein (GFP) (rAMTV-GFP) or that expressing Renilla luciferase (rAMTV-rLuc) from cloned cDNA. The rAMTV-rLuc and the RVFV rMP12-rLuc showed a similar susceptibility to favipiravir or ribavirin. Interestingly, neither of rAMTV nor rAMTVΔNSs replicated efficiently in human MRC-5 or A549 cells, regardless of the presence of NSs gene. Little accumulation of AMTV NSs protein occurred in those cells, which was restored via treatment with proteasomal inhibitor MG132. In murine MEF or Hepa1-6 cells, rAMTV, but not rAMTVΔNSs, replicated efficiently, with an inhibition of IFN-β gene upregulation. This study showed an establishment of the first reverse genetics for AMTV, a lack of stability of AMTV NSs proteins in human cells, and an IFN-β gene antagonist function of AMTV NSs proteins in murine cells. The AMTV can be a nonpathogenic surrogate model for studying phleboviruses including RVFV.
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Affiliation(s)
- Hoai J. Hallam
- Department of Pathology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Nandadeva Lokugamage
- Department of Pathology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Tetsuro Ikegami
- Department of Pathology, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
- Sealy Institute for Vaccine Sciences, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
- Center for Biodefense and Emerging Infectious Diseases, The University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
- * E-mail:
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Kotla S, Gustin KE. Proteolysis of MDA5 and IPS-1 is not required for inhibition of the type I IFN response by poliovirus. Virol J 2015; 12:158. [PMID: 26437794 PMCID: PMC4595118 DOI: 10.1186/s12985-015-0393-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 09/23/2015] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The type I interferon (IFN) response is a critical component of the innate immune response to infection by RNA viruses and is initiated via recognition of viral nucleic acids by RIG-like receptors (RLR). Engagement of these receptors in the cytoplasm initiates a signal transduction pathway leading to activation of the transcription factors NF-κB, ATF-2 and IRF-3 that coordinately upregulate transcription of type I IFN genes, such as that encoding IFN-β. In this study the impact of poliovirus infection on the type I interferon response has been examined. METHODS The type I IFN response was assessed by measuring IFN-β mRNA levels using qRT-PCR and normalizing to levels of β-actin mRNA. The status of host factors involved in activation of the type I IFN response was examined by immunoblot, immunofluorescence microcopy and qRT-PCR. RESULTS The results show that poliovirus infection results in induction of very low levels of IFN-β mRNA despite clear activation of NF-κB and ATF-2. In contrast, analysis of IRF-3 revealed no transcriptional induction of an IRF-3-responsive promoter or homodimerization of IRF-3 indicating it is not activated in poliovirus-infected cells. Exposure of poliovirus-infected cells to poly(I:C) results in lower levels of IFN-β mRNA synthesis and IRF-3 activation compared to mock-infected cells. Analysis of MDA-5 and IPS-1 revealed that these components of the RLR pathway were largely intact at times when the type I IFN response was suppressed. CONCLUSIONS Collectively, these results demonstrate that poliovirus infection actively suppresses the host type I interferon response by blocking activation of IRF-3 and suggests that this is not mediated by cleavage of MDA-5 or IPS-1.
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Affiliation(s)
- Swathi Kotla
- Present address: Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Kurt E Gustin
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, 85004, USA.
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Wang N, Dong Q, Li J, Jangra RK, Fan M, Brasier AR, Lemon SM, Pfeffer LM, Li K. Viral induction of the zinc finger antiviral protein is IRF3-dependent but NF-kappaB-independent. J Biol Chem 2010; 285:6080-90. [PMID: 20048147 DOI: 10.1074/jbc.m109.054486] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The zinc finger antiviral protein (ZAP) is an interferon-stimulated gene that restricts the replication of retroviruses, alphaviruses, and filoviruses. Relatively little is known, however, regarding the detailed mechanism of ZAP induction during viral infections. We show that, although being inducible by either interferon or virus, expression of ZAP is more efficiently activated by virus than are several other classical interferon-stimulated genes and that viral induction of ZAP occurs under the direct control of interferon regulatory factor 3 (IRF3) independent of interferon paracrine/autocrine signaling. ZAP was up-regulated in cells unresponsive to type I and III interferons upon engagement of TLR3, retinoic inducible gene I/melanoma differentiation-associated gene 5 pathways, or ectopic expression of a constitutively active IRF3 mutant. Conversely, induction of ZAP by virus or dsRNA was severely impaired in cells expressing a dominant-negative mutant IRF3 and completely abrogated in cells lacking IRF3. In contrast to IRF3, ZAP induction was independent of NF-kappaB activity. Mutational analysis of the human ZAP promoter revealed that multiple interferon-stimulated response elements far distal to the transcription start site serve redundantly to control IRF3-dependent induction of ZAP transcription. Chromatin immunoprecipitation assays demonstrated that IRF3 selectively binds the distal interferon-stimulated response elements in human ZAP promoter following viral infection. Collectively, these data suggest that ZAP is a direct target gene of IRF3 action in cellular antiviral responses.
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Affiliation(s)
- Nan Wang
- Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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Liao WP, DeHaven J, Shao J, Chen JX, Rojanasakul Y, Lamm DL, Ma JK. Liposomal delivery of α-Interferon to murine bladder tumor cells via transferrin receptor-mediated endocytosis. Drug Deliv 2009; 5:111-8. [DOI: 10.3109/10717549809031386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Gilfoy FD, Mason PW. West Nile virus-induced interferon production is mediated by the double-stranded RNA-dependent protein kinase PKR. J Virol 2007; 81:11148-58. [PMID: 17686861 PMCID: PMC2045557 DOI: 10.1128/jvi.00446-07] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Cells carry a variety of molecules, referred to as pathogen recognition receptors (PRRs), which are able to sense invading pathogens. Interaction of PRRs with viral compounds instigates a signaling pathway(s), resulting in the activation of genes, including those for type I interferon (IFN), which are critical for an effective antiviral response. Here we demonstrate that the double-stranded RNA (dsRNA)-dependent protein kinase PKR, which has been shown to function as a PRR in cells treated with the dsRNA mimetic poly(I:C), serves as a PRR in West Nile virus (WNV)-infected cells. Evidence for PKR's role as a PRR was obtained from both human and murine cells. Using mouse embryonic fibroblasts (MEFs), we demonstrated that PKR gene knockout, posttranscriptional gene silencing of PKR mRNA using small interfering RNA (siRNA), and chemical inhibition of PKR function all interfered with IFN synthesis following WNV infection. In three different human cell lines, siRNA knockdown and chemical inhibition of PKR blocked WNV-induced IFN synthesis. Using the same approaches, we demonstrated that PKR was not necessary for Sendai virus-induced IFN synthesis, suggesting that PKR is particularly important for recognition of WNV infection. Taken together, our data suggest that PKR could serve as a PRR for recognition of WNV infection.
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Affiliation(s)
- Felicia D Gilfoy
- Department of Pathology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0436, USA
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7
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Abstract
HEC-1 cell line was the first in vitro cell line of a human endometrial adenocarcinoma which enabled us to perform research work on the endometrium and endometrial carcinoma at a simplified cellular system, contributing cell and molecular biological studies on endometrial carcinoma. Once a cell line is established, it provides a stable experimental system that facilitates and progresses in the study of the tissues and/or neoplasias from which they are derived. In this article we report how HEC-1 cells have been established and cleared the proposed requirements to characterize the established cell line. Also to show the usefulness of the cell line for research work, once it was established, we illustrate these concepts by recalling results obtained with HEC-1 cells and reviewing the literature on what has been achieved by using these cells.
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Affiliation(s)
- Hiroyuki Kurarmoto
- Department of Clinical Cytology Graduate School of Medical Sciences, School of Medicine, Kitasato University, Sagamihara, Kanagawa, Japan.
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Parisien JP, Lau JF, Rodriguez JJ, Ulane CM, Horvath CM. Selective STAT protein degradation induced by paramyxoviruses requires both STAT1 and STAT2 but is independent of alpha/beta interferon signal transduction. J Virol 2002; 76:4190-8. [PMID: 11932384 PMCID: PMC155111 DOI: 10.1128/jvi.76.9.4190-4198.2002] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2001] [Accepted: 01/29/2002] [Indexed: 12/28/2022] Open
Abstract
The alpha/beta interferon (IFN-alpha/beta)-induced STAT signal transduction pathway leading to activation of the ISGF3 transcription complex and subsequent antiviral responses is the target of viral pathogenesis strategies. Members of the Rubulavirus genus of the Paramyxovirus family of RNA viruses have acquired the ability to specifically target either STAT1 or STAT2 for proteolytic degradation as a countermeasure for evading IFN responses. While type II human parainfluenza virus induces STAT2 degradation, simian virus 5 induces STAT1 degradation. The components of the IFN signaling system that are required for STAT protein degradation by these paramyxoviruses have been investigated in a series of human somatic cell lines deficient in IFN signaling proteins. Results indicate that neither the IFN-alpha/beta receptor, the tyrosine kinases Jak1 or Tyk2, nor the ISGF3 DNA-binding subunit, IFN regulatory factor 9 (IRF9), is required for STAT protein degradation induced by either virus. Nonetheless, both STAT1 and STAT2 are strictly required in the host cell to establish a degradation-permissive environment enabling both viruses to target their respective STAT protein. Complementation studies reveal that STAT protein-activating tyrosine phosphorylation and functional src homology 2 (SH2) domains are dispensable for creating a permissive STAT degradation environment in degradation-incompetent cells, but the N terminus of the missing STAT protein is essential. Protein-protein interaction analysis indicates that V and STAT proteins interact physically in vitro and in vivo. These results constitute genetic and biochemical evidence supporting a virus-induced, IFN-independent STAT protein degradation complex that contains at least STAT1 and STAT2.
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Affiliation(s)
- Jean-Patrick Parisien
- Immunobiology Center, The Mount Sinai School of Medicine, New York, New York 10029, USA
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9
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Player MR, Torrence PF. The 2-5A system: modulation of viral and cellular processes through acceleration of RNA degradation. Pharmacol Ther 1998; 78:55-113. [PMID: 9623881 PMCID: PMC7157933 DOI: 10.1016/s0163-7258(97)00167-8] [Citation(s) in RCA: 227] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The 2-5A system is an RNA degradation pathway that can be induced by the interferons (IFNs). Treatment of cells with IFN activates genes encoding several double-stranded RNA (dsRNA)-dependent synthetases. These enzymes generate 5'-triphosphorylated, 2',5'-phosphodiester-linked oligoadenylates (2-5A) from ATP. The effects of 2-5A in cells are transient since 2-5A is unstable in cells due to the activities of phosphodiesterase and phosphatase. 2-5A activates the endoribonuclease 2-5A-dependent RNase L, causing degradation of single-stranded RNA with moderate specificity. The human 2-5A-dependent RNase is an 83.5 kDa polypeptide that has little, if any, RNase activity, unless 2-5A is present. 2-5A binding to RNase L switches the enzyme from its off-state to its on-state. At least three 2',5'-linked oligoadenylates and a single 5'-phosphoryl group are required for maximal activation of the RNase. Even though the constitutive presence of 2-5A-dependent RNase is observed in nearly all mammalian cell types, cellular amounts of 2-5A-dependent mRNA and activity can increase after IFN treatment. One well-established role of the 2-5A system is as a host defense against some types of viruses. Since virus infection of cells results in the production and secretion of IFNs, and since dsRNA is both a frequent product of virus infection and an activator of 2-5A synthesis, the replication of encephalomyocarditis virus, which produces dsRNA during its life cycle, is greatly suppressed in IFN-treated cells as a direct result of RNA decay by the activated 2-5A-dependent RNase. This review covers the organic chemistry, enzymology, and molecular biology of 2-5A and its associated enzymes. Additional possible biological roles of the 2-5A system, such as in cell growth and differentiation, human immunodeficiency virus replication, heat shock, atherosclerotic plaque, pathogenesis of Type I diabetes, and apoptosis, are presented.
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Affiliation(s)
- M R Player
- Section on Biomedical Chemistry, Laboratory of Medicinal Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0805, USA
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10
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Weaver BK, Kumar KP, Reich NC. Interferon regulatory factor 3 and CREB-binding protein/p300 are subunits of double-stranded RNA-activated transcription factor DRAF1. Mol Cell Biol 1998; 18:1359-68. [PMID: 9488451 PMCID: PMC108849 DOI: 10.1128/mcb.18.3.1359] [Citation(s) in RCA: 276] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/1997] [Accepted: 12/10/1997] [Indexed: 02/06/2023] Open
Abstract
Cells respond to viral infection or double-stranded RNA with the transcriptional induction of a subset of alpha/beta interferon-stimulated genes by a pathway distinct from the interferon signal pathway. The transcriptional induction is mediated through a DNA sequence containing the alpha/beta interferon-stimulated response element (ISRE). We previously identified a novel transcription factor, designated double-stranded RNA-activated factor 1 (DRAF1), that recognizes this response element. The DNA-binding specificity of DRAF1 correlates with transcriptional induction, thereby distinguishing it as a positive regulator of alpha/beta interferon-stimulated genes. Two of the components of DRAF1 have now been identified as interferon regulatory factor 3 (IRF-3) and the transcriptional coactivator CREB-binding protein (CBP)/p300. We demonstrate that IRF-3 preexists in the cytoplasm of uninfected cells and translocates to the nucleus following viral infection. Translocation of IRF-3 is accompanied by an increase in serine and threonine phosphorylation. Coimmunoprecipitation analyses of endogenous proteins demonstrate an association of IRF-3 with the transcriptional coactivators CBP and p300 only subsequent to infection. In addition, antibodies to the IRF-3, CBP, and p300 molecules react with DRAF1 bound to the ISRE target site of induced genes. The cellular response that leads to DRAF1 activation and specific gene expression may serve to increase host survival during viral infection.
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Affiliation(s)
- B K Weaver
- Department of Pathology, State University of New York at Stony Brook, 11794, USA
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11
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Interferon-α Resistance in a Cutaneous T-Cell Lymphoma Cell Line Is Associated With Lack of STAT1 Expression. Blood 1998. [DOI: 10.1182/blood.v91.2.570] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractInterferon-alpha (IFNα) mediates its biological effects through activation of the JAK-STAT signaling pathway and it has been shown to be one of most effective therapeutic agents for a number of hematological malignancies, including cutaneous T-cell lymphoma (CTCL). Nevertheless, its efficacy is limited by the development of clinical resistance but the reasons for resistance in CTCL are unknown. Here, we report the development of an IFNα-resistant CTCL cell line (HUT78R), characterized by its ability to proliferate in high concentration of recombinant IFNα, which can be used as a model system to study IFN resistance. The levels of IFN receptor expression and binding affinity were found to be comparable between the parental sensitive (HUT78S) and resistant (HUT78R) cells. However, IFNα stimulation failed to induce interferon-stimulated gene factor 3 (ISGF3) complex formation in HUT78R cells. In addition, the expression of the IFN-inducible 2-5 OAS gene was significantly reduced in HUT78R cells, suggesting the presence of a defect in the Jak-STAT signaling pathway. Our results showed that the IFNα-activated form of a latent transcriptional factor STAT1 was not found in HUT78R cells, whereas activated STAT2 and STAT3 were clearly detectable. By Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses, we found that HUT78R cells do not express any STAT1 protein or mRNA, suggesting the possibility of a null mutation in the STAT1 gene. Resistance to the growth inhibitory effect of IFNα in CTCL cells may result from lack of STAT1 expression.
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12
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Interferon-α Resistance in a Cutaneous T-Cell Lymphoma Cell Line Is Associated With Lack of STAT1 Expression. Blood 1998. [PMID: 9427711 DOI: 10.1182/blood.v91.2.570.570_570_576] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interferon-alpha (IFNα) mediates its biological effects through activation of the JAK-STAT signaling pathway and it has been shown to be one of most effective therapeutic agents for a number of hematological malignancies, including cutaneous T-cell lymphoma (CTCL). Nevertheless, its efficacy is limited by the development of clinical resistance but the reasons for resistance in CTCL are unknown. Here, we report the development of an IFNα-resistant CTCL cell line (HUT78R), characterized by its ability to proliferate in high concentration of recombinant IFNα, which can be used as a model system to study IFN resistance. The levels of IFN receptor expression and binding affinity were found to be comparable between the parental sensitive (HUT78S) and resistant (HUT78R) cells. However, IFNα stimulation failed to induce interferon-stimulated gene factor 3 (ISGF3) complex formation in HUT78R cells. In addition, the expression of the IFN-inducible 2-5 OAS gene was significantly reduced in HUT78R cells, suggesting the presence of a defect in the Jak-STAT signaling pathway. Our results showed that the IFNα-activated form of a latent transcriptional factor STAT1 was not found in HUT78R cells, whereas activated STAT2 and STAT3 were clearly detectable. By Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses, we found that HUT78R cells do not express any STAT1 protein or mRNA, suggesting the possibility of a null mutation in the STAT1 gene. Resistance to the growth inhibitory effect of IFNα in CTCL cells may result from lack of STAT1 expression.
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13
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Affiliation(s)
- N Fujii
- Department of Microbiology, Sapporo Medical College, Hokkaido, Japan
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14
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Double-stranded RNA activates novel factors that bind to the interferon-stimulated response element. Mol Cell Biol 1993. [PMID: 8388546 DOI: 10.1128/mcb.13.6.3756] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection of cells with adenovirus or transfection of cells with double-stranded RNA (dsRNA) activates transcription of the alpha/beta interferon-stimulated genes (ISGs). Induction of ISG expression by adenovirus appears to be mediated through the same DNA target that is responsive to alpha/beta interferons, the interferon-stimulated response element (ISRE). Transcriptional induction by alpha/beta interferons has been shown previously to be mediated by the activation of a latent cytoplasmic transcription factor, ISGF3, that translocates to the nucleus and binds to the ISRE. However, ISG expression induced by adenovirus or dsRNA appears to be mediated by unique dsRNA-activated factors (DRAFs) that bind to the ISRE. The activation of these preexisting factors by dsRNA does not require new protein synthesis. Two DRAFs, DRAF1 and DRAF2, have been identified in our studies as ISRE-binding complexes in gel mobility shift assays. The ISRE-binding specificity of DRAF1 is similar to that of ISGF3; however, the ISRE-binding specificity of DRAF2 is distinct. Activation of DRAF1 and DRAF2 is independent of interferon action since it occurs in cells that are nonresponsive to interferon and in cells that lack the alpha/beta interferon locus. The activation pathway of DRAF1 and DRAF2 is blocked by the protein kinase inhibitors staurosporine and genistein. This is analogous to the interferon signal transduction pathway and suggests that phosphorylation, possibly tyrosine phosphorylation, is involved in activation of these factors.
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15
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Daly C, Reich NC. Double-stranded RNA activates novel factors that bind to the interferon-stimulated response element. Mol Cell Biol 1993; 13:3756-64. [PMID: 8388546 PMCID: PMC359855 DOI: 10.1128/mcb.13.6.3756-3764.1993] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Infection of cells with adenovirus or transfection of cells with double-stranded RNA (dsRNA) activates transcription of the alpha/beta interferon-stimulated genes (ISGs). Induction of ISG expression by adenovirus appears to be mediated through the same DNA target that is responsive to alpha/beta interferons, the interferon-stimulated response element (ISRE). Transcriptional induction by alpha/beta interferons has been shown previously to be mediated by the activation of a latent cytoplasmic transcription factor, ISGF3, that translocates to the nucleus and binds to the ISRE. However, ISG expression induced by adenovirus or dsRNA appears to be mediated by unique dsRNA-activated factors (DRAFs) that bind to the ISRE. The activation of these preexisting factors by dsRNA does not require new protein synthesis. Two DRAFs, DRAF1 and DRAF2, have been identified in our studies as ISRE-binding complexes in gel mobility shift assays. The ISRE-binding specificity of DRAF1 is similar to that of ISGF3; however, the ISRE-binding specificity of DRAF2 is distinct. Activation of DRAF1 and DRAF2 is independent of interferon action since it occurs in cells that are nonresponsive to interferon and in cells that lack the alpha/beta interferon locus. The activation pathway of DRAF1 and DRAF2 is blocked by the protein kinase inhibitors staurosporine and genistein. This is analogous to the interferon signal transduction pathway and suggests that phosphorylation, possibly tyrosine phosphorylation, is involved in activation of these factors.
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Affiliation(s)
- C Daly
- Department of Pathology, State University of New York, Stony Brook 11794-8691
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Witt PL, Marié I, Robert N, Irizarry A, Borden EC, Hovanessian AG. Isoforms p69 and p100 of 2',5'-oligoadenylate synthetase induced differentially by interferons in vivo and in vitro. JOURNAL OF INTERFERON RESEARCH 1993; 13:17-23. [PMID: 8454907 DOI: 10.1089/jir.1993.13.17] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Four isoforms of 2',5'-oligoadenylate (2-5A) synthetase have been identified (40, 44, 69, and 100 kD). The 40- and 44-kD enzymes are encoded by the same gene, probably different from the genes encoding the larger isoforms. In this study, induction of the 100- and 69-KD (p100, p69) isoforms in different individuals and in different cell types was investigated after treatment with recombinant human interferons (IFN): IFN-alpha 2, IFN-beta ser, or IFN-gamma. The p69 and p100 isoforms were quantitated in cell extracts on Western blots using specific polyclonal antibodies, or their activity was measured after purification of cell extracts on immunoaffinity columns. The p69 and p100 isoforms were differentially induced in Daudi, fibroblast, and colon adenocarcinoma cells treated with IFNs. Considerable individual variations in both basal and induced levels of p69 and p100 were observed in peripheral blood mononuclear cells from normal donors cultured with IFNs in vitro, and from cancer patients treated with IFN-alpha 2 or with IFN-beta ser. These results demonstrate that the p69 and p100 isoforms are present in vivo in peripheral blood mononuclear cells and their level is increased following IFN administration. Furthermore, both the in vivo and in vitro observations indicate that the expression of these enzymes is specific to each cell type and varies among individuals.
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Affiliation(s)
- P L Witt
- Department of Microbiology, Medical College of Wisconsin, Milwaukee
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17
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Rysiecki G, Gewert DR, Williams BR. Constitutive expression of a 2',5'-oligoadenylate synthetase cDNA results in increased antiviral activity and growth suppression. JOURNAL OF INTERFERON RESEARCH 1989; 9:649-57. [PMID: 2481699 DOI: 10.1089/jir.1989.9.649] [Citation(s) in RCA: 116] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The interferon (IFN)-induced enzyme 2',5'-oligoadenylate (2-5A) synthetase has been implicated in the development of antiviral activity in human and animal cells. However, its role in IFN-mediated growth inhibition remains unclear. To elucidate the function of 2-5A synthetase, we have stably introduced a human 2-5A synthetase cDNA into a human glioblastoma cell line (T98G). Constitutive expression of the cDNA in these cells is associated with increased levels of resistance to infection by encephalomyocarditis virus. One transfected subclone, which expresses elevated levels of 2-5A synthetase enzyme activity, also shows a reduced rate of cellular proliferation.
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Affiliation(s)
- G Rysiecki
- Division of Infectious Diseases, Hospital for Sick Children, Toronto, Ontario, Canada
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18
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David S, Nissim A, Chebath J, Salzberg S. 2'-5'-oligoadenylate synthetase gene expression in normal and murine sarcoma virus-transformed NIH 3T3 cells. J Virol 1989; 63:1116-22. [PMID: 2536824 PMCID: PMC247806 DOI: 10.1128/jvi.63.3.1116-1122.1989] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Mouse fibroblasts transformed by murine sarcoma virus (MSV) are highly sensitive to the antiproliferative effect of interferon (IFN) (M. Bakhanashvili, D. H. Wreschner, and S. Salzberg, Cancer Res. 43:1289-1294, 1983). To elucidate the mechanism leading to this IFN sensitivity, the expression of the 2'-5'-oligoadenylate synthetase (2-5A synthetase) gene, the presence of the 2-5A synthetase protein, and the level of its enzymatic activity were determined in IFN-treated and untreated cultures. NIH 3T3 mouse fibroblasts were compared with two different NIH 3T3 clones transformed by MSV. Cultures were treated with 300 IU of beta IFN (IFN-beta) per ml for 16 to 24 h. While no detectable 2-5A synthetase-derived transcripts were seen in untreated NIH 3T3 cells, two size classes of RNA transcripts, i.e., 1.7 and 4.2 kilobases, were detected in IFN-treated cultures. Surprisingly, a similar amount of transcripts were present in untreated transformed cells. However, following IFN treatment, an eightfold increase in the level of RNA was readily detected in these cells, with no change in the size classes. Similar results were obtained with the 2-5A synthetase protein, for which three size classes of 42, 71, and 102 kilodaltons were demonstrated by immunoblotting, and with the enzymatic activity, for which again, the highest level was seen in IFN-treated MSV-transformed cultures. The basal level of 2-5A synthetase gene expression in the transformed cells has biological significance since these cells were more resistant to mengovirus infection than NIH 3T3 mouse fibroblasts. Medium collected from transformed cultures failed to induce 2-5A synthetase activity in NIH 3T3 cells. Furthermore, antibodies directed against mouse IFN-beta failed to inhibit 2-5A synthetase activity detected in transformed cultures. These results suggest that at least IFN-beta secretion is not involved in the elevated level of 2-5A synthetase gene expression in these cells.
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Affiliation(s)
- S David
- Department of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
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19
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Nakamura K, Eizuru Y, Minamishima Y. Effect of natural human interferon-beta on the replication of human cytomegalovirus. J Med Virol 1988; 26:363-73. [PMID: 2850341 DOI: 10.1002/jmv.1890260404] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The antiviral effect of natural human interferon-beta (HuIFN-beta) against human cytomegalovirus (CMV) was evaluated in human embryonic lung fibroblasts (HEL). Natural HuIFN-beta, like other HuIFNs, inhibited the replication of CMV. Pretreatment of the cells with natural HuIFN-beta inhibited the appearance of immediate-early antigen (IEA) or pre-early nuclear antigen (PENA) as well as the production of infectious CMV. After a single treatment with natural HuIFN-beta, intracellular 2', 5'-oligoadenylate (2-5A) synthetase activity was induced and maintained at a high level for several days. The anti-CMV effect of natural HuIFN-beta correlated with the intracellular 2-5A synthetase activity.
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Affiliation(s)
- K Nakamura
- Department of Microbiology, Miyazaki Medical College, Japan
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20
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Nakamura K, Eizuru Y, Minamishima Y. Effect of recombinant murine interferon-beta on the replication of murine cytomegalovirus. Microbiol Immunol 1988; 32:925-31. [PMID: 2850448 DOI: 10.1111/j.1348-0421.1988.tb01454.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Pretreatment of mouse embryo fibroblasts (MEF) with recombinant murine interferon-beta (rMuIFN-beta) induced a high level of intracellular 2',5'-oligoadenylate (2-5A) synthetase activity. However, murine cytomegalovirus (MCMV) replicated under such condition, indicating that MCMV is relatively insensitive in vitro to rMuIFN-beta. Thus, there was a dissociation of 2-5A synthetase activity and antiviral activity against MCMV. In contrast to MCMV, the two parameters were closely associated in the case of vesicular stomatitis virus (VSV).
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Affiliation(s)
- K Nakamura
- Department of Microbiology, Miyazaki Medical College
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21
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Wathelet MG, Clauss IM, Content J, Huez GA. Regulation of two interferon-inducible human genes by interferon, poly(rI).poly(rC) and viruses. EUROPEAN JOURNAL OF BIOCHEMISTRY 1988; 174:323-9. [PMID: 2454816 DOI: 10.1111/j.1432-1033.1988.tb14101.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The IFI-56K and IFI-54K genes are transcriptionally stimulated when cells are treated by interferon. We have previously shown that the IFI-56K gene is in addition directly induced by poly(rI).poly(rC), and inducer of interferon-beta. Since the regulation of the IFI-56K and IFI-54K genes by interferon are very much alike, we tested whether the IFI-54K gene is also directly regulated by poly(rI).poly(rC). Treatment of various cell lines with poly(rI).poly(rC) leads to a clear accumulation of the IFI-54K mRNA to a level which sometimes even exceeds that obtained with high doses of interferon. Several interferon-resistant cell lines were investigated for the inducibility of both the IFI-56K and IFI-54K genes by interferons, poly(rI).poly(rC) and viruses (which are the natural inducers of interferon-alpha and -beta). Both genes appear to be coordinately regulated by these inducers. It was thus interesting to search for common regulatory element(s) in the control region of these two genes. The IFI-54K gene promoter region was isolated, from which a 520-base-pair segment was sequenced and compared with the promoter region of the IFI-56K gene that we had previously sequenced. The only homology was found is a well conserved 19-bp segment located just upstream of the TATA box of these genes; interestingly, this sequence is also homologous to the minimal region needed for the inducibility by poly(rI).poly(rC) of the interferon-beta gene. This conserved sequence might be responsible for the coordinate induction of the IFI-56K and IFI-54K genes by interferon, poly(rI).poly(rC) and viruses.
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Affiliation(s)
- M G Wathelet
- Département de Biologie Moléculaire, Université Libre de Bruxelles, Rhode-St-Genèse, Belgium
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22
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Abstract
Interferons can regulate growth and differentiation in a wide range of cell types. These mechanisms are currently being examined. Interferons inhibit the growth of tumour cells and are thus potential anti-cancer agents. They can also inhibit normal cell growth in vitro, and stimulate tumour cell growth in vitro. They may also be involved in some autoimmune diseases. This review examines the effect of interferons on cell proliferation, function, and growth, focusing primarily on in vitro cell systems.
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Affiliation(s)
- M Shearer
- Imperial Cancer Research Fund, London, U.K
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23
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Modification, after heat-shock, of the antiviral state induced by interferon in murine L cells. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/s0769-2617(87)80021-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Saito T, Berens ME, Welander CE. Interferon-gamma and cytotoxic agents studied in combination using a soft agarose human tumor clonogenic assay. Cancer Chemother Pharmacol 1987; 19:233-9. [PMID: 3107848 DOI: 10.1007/bf00252978] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The in vitro antiproliferative activity of human recombinant interferon-gamma (IFN-gamma) was tested against human tumor cells in vitro in combination with doxorubicin, cisplatin, or vinblastine. Using a human tumor clonogenic assay (HTCA), IFN-gamma alone showed dose-dependent inhibition of colony growth in six or seven human tumor cell lines as well as in each of nine fresh ovarian tumor specimens. The combination of IFN-gamma and either doxorubicin or cisplatin showed additive antiproliferative effects against all the cell lines with the exception of an IFN-gamma-resistant endometrial cancer cell line (HEC-1A). In combination with vinblastine, IFN-gamma rarely had an additive effect. Inclusion of macrophages from malignant effusions in the HTCA potentiated the antiproliferative effect of IFN-gamma alone as well as the combination of IFN-gamma and doxorubicin; however, the efficacy of the two agents was never more than additive. The results show that combinations of IFN-gamma with doxorubicin or cisplatin are additive and warrant further investigation. The antitumor effect of IFN-gamma alone or in combination with cytotoxic drugs may be significantly enhanced by tumor-associated macrophages.
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25
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Wathelet M, Moutschen S, Cravador A, DeWit L, Defilippi P, Huez G, Content J. Full-length sequence and expression of the 42 kDa 2-5A synthetase induced by human interferon. FEBS Lett 1986; 196:113-20. [PMID: 3753689 DOI: 10.1016/0014-5793(86)80224-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Interferon-induced 2-5A synthetases are probably involved in some antiviral actions of interferon. In human cells two different mRNAs (1.6, 1.8 kb long) coding for this protein are transcribed from the same gene and are produced by differential splicing. The relationship between the two mRNAs of different size and the active enzyme is not clear, nor is the cellular localization of the latter known. We have cloned a cDNA corresponding to the 1.6 kb RNA. This cDNA was sequenced and its complete coding region was subcloned into pSP64. The resulting plasmid was used to direct the synthesis of micrograms of capped RNA transcript after linearization in the 3'-non-coding region. A 39 kDa protein was synthesized when this RNA was translated in rabbit reticulocyte lysate. When this capped RNA was introduced by microinjection into Xenopus oocytes, production of 2-5A synthetase was clearly observed in the cytoplasm and 10-30% of the enzyme accumulated with time in the nucleoplasm. Analysis of cytoplasmic homogenates of these oocytes on a glycerol gradient revealed that the enzyme is fully active in the monomeric form.
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26
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Cordycepin analogs of ppp5'A2‘p5'A2‘p5'A (2-5A) inhibit protein synthesis through activation of the 2-5A-dependent endonuclease. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(19)83674-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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27
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Clemens MJ, McNurlan MA. Regulation of cell proliferation and differentiation by interferons. Biochem J 1985; 226:345-60. [PMID: 2581554 PMCID: PMC1144719 DOI: 10.1042/bj2260345] [Citation(s) in RCA: 184] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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28
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Taira H, Yamamoto F, Furusawa M, Sawai H, Kawakita M. Comparative studies on (2'-5')oligoadenylate-related enzyme systems and the antiviral effect of interferon in two mouse cell lines which differ in (2'-5')oligoadenylate sensitivity of their protein synthesizing system. JOURNAL OF INTERFERON RESEARCH 1985; 5:583-96. [PMID: 2418128 DOI: 10.1089/jir.1985.5.583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Effect of (2'-5')oligoadenylate (2-5A) on cellular and viral protein and RNA syntheses was investigated with two mouse cell lines, L929 and Lz (a subclone of L929). The oligonucleotide was introduced into the cells either by using calcium phosphate coprecipitation technique or by microinjection method. In L929 cells protein and viral RNA syntheses were severely inhibited by 2-5A, whereas in Lz cells, both were only slightly inhibited. The activities of 2-5A synthetase and double-stranded (ds)RNA-dependent protein kinase were enhanced by interferon (IFN) treatment roughly to the same extent and there was no significant difference in the level of 2'-5' phosphodiesterase activity either. On the other hand, 2-5A-dependent RNase (RNase L) activity in Lz cells was low, being about 10-20% of that of L929 cells. It was increased twofold after IFN treatment, but protein synthesis of Lz cells was not as sensitive to 2-5A as that of L929 cells even after IFN treatment. L929 and Lz cells were sensitive to the antiviral effect of mouse IFN against vesicular stomatitis virus (VSV) and Mengovirus. In contrast, however, Lz cells were relatively insensitive to the antiviral effect of IFN on vaccinia virus, whereas L929 cells were sensitive.
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29
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Veomett GE, Kumor N, Lahm BD. Characteristics of the induction of two double-stranded RNA-dependent enzymes by interferon in parental and variant L cells. JOURNAL OF INTERFERON RESEARCH 1985; 5:327-37. [PMID: 2409193 DOI: 10.1089/jir.1985.5.327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The interferon (IFN)-dependent induction of two double-stranded RNA-dependent enzymes was examined in L cells and an L-cell variant (WDIFN) which is highly resistant to the inhibitory effects of IFN on cellular multiplication. IFN, in a concentration-dependent manner, inhibited the multiplication of parental L cells and induced increased levels of the double-stranded RNA-dependent enzymes in parental L cells. Although WDIFN cells were resistant to the antiproliferative effects of IFN, the cells responded to IFN by increasing their levels of the double-stranded RNA-dependent enzymes. However, the level of activity of each enzyme was lower in the WDIFN line than the parental line when both lines were treated with similar concentrations of IFN. The reduced response of the WDIFN line was not the result of the line being a heterogeneous population of cells nor of IFN being more unstable in the presence of WDIFN cells. In addition there was no evidence that WDIFN cells produced a mitogenic factor that could overcome the antiproliferative effects of IFN, nor that sodium butyrate could increase the sensitivity of WDIFN cells to the antiproliferative effects of IFN.
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30
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Nagata Y, Rosen OM, Makman MH, Bloom BR. Biochemical analysis of mutants of a macrophage cell line resistant to the growth-inhibitory activity of interferon. J Cell Biol 1984; 98:1342-7. [PMID: 6325469 PMCID: PMC2113213 DOI: 10.1083/jcb.98.4.1342] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
While a multiplicity of cellular and biochemical effects are mediated by interferons on cultured cells, the mechanisms involved in the direct growth-inhibitory activity of interferons remain problematic. We have previously found that variants in cAMP metabolism in a macrophage cell line, J774.2, were at least 50-fold less sensitive to the growth inhibitory activity of interferons (IFN) than the parental clone. To test the hypothesis that cAMP mediates the growth inhibition produced by IFN in these cells, interferon-resistant variants were selected and characterized with respect to cAMP synthesis and function. Approximately one-third of the IFN-resistant clones were found to be resistant to growth inhibition produced by cholera toxin, but not 8Br-cAMP. IFN was fully able to protect all of the interferon-resistant/choleratoxin-resistant (IFNr/CTr) clones against infection by vesicular stomatitis virus and markedly stimulated 2', 5'-oligodenylate synthetase activity. These IFNr/CTr variants were shown to have a defect in adenylate cyclase. The remaining IFN-resistant clones were fully susceptible to the growth-inhibitory effects of cholera toxin because their basal and stimulated adenylate cyclase activity is similar to that of the parental clone. IFN failed to protect these IFNr/choleratoxin sensitive clones against infection by vesicular stomatitis virus and failed to stimulate 2', 5-oligodenylate synthetase, suggesting that they have defective or deficient IFN receptors. In addition, IFN failed to increase intracellular cAMP levels in both IFNr/CTr and IFNr/choleratoxin sensitive clones. These results provide firm genetic and biochemical evidence that the growth inhibitory effects of IFN on this cell line are mediated by cAMP.
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31
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Greene JJ, Dyer RH, Yang LC, Ts'o PO. Developmentally regulated expression of the interferon system during Syrian hamster embryogenesis. JOURNAL OF INTERFERON RESEARCH 1984; 4:517-27. [PMID: 6209348 DOI: 10.1089/jir.1984.4.517] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Expression of interferon (IFN) during embryogenesis of the Syrian hamster has been characterized with respect to (1) the antiviral activity to IFN; (2) the activity of the IFN-induced enzyme, 2',5'-oligo A synthetase; (3) the subpopulation of IFN producing cells, and (4) the molecular structure of the elaborated IFN. These components of the IFN system were examined in cell cultures derived from embryos excised at 8-13 days of gestation and determined as a function of both in utero gestation and in vitro passaging. The antiviral responsiveness of nine-day gestation cultures (9 dgc) was 1/4-1/6 of that of 13 dgc, but in vitro passaging increased the responsiveness as did in vivo development. IFN enhancement of the synthetase level in 9 dgc was only minimal when compared with that in 13 dgc. However, the 9 dgc contained an unusually high basal level of the enzyme. During in vivo development and in vitro passaging, the basal levels of the enzymes progressively declined while the IFN-induced levels progressively increased. IFN production in embryo cells following induction by Newcastle disease virus differs substantially, depending on the gestational age of the cells. Using an agarose-overlay "zone of protection" assay, 8 dgc were found to contain 10-12 times the number of cells producing zones of protection than 13 dgc. Passaging of 9 dgc cells reduced the number of zones to the level of the 13 dgc, but had no effect on 13 dgc. Chromatographic analysis of IFN produced by 9 dgc and 13 dgc revealed the presence of an additional, unique species of "embryonic" IFN in 9 dgc which was not observed in IFN from 13 dgc. These observations suggest that the expression of various components of the IFN system are under developmental control during embryogenesis.
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Masters PS, Samuel CE. Mechanism of interferon action: inhibition of vesicular stomatitis virus replication in human amnion U cells by cloned human leukocyte interferon. II. Effect on viral macromolecular synthesis. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)44335-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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33
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Masters PS, Samuel CE. Mechanism of interferon action: inhibition of vesicular stomatitis virus replication in human amnion U cells by cloned human leukocyte interferon. I. Effect on early and late stages of the viral multiplication cycle. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)44334-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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34
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Growth regulation of melanoma cells by interferon and (2'-5')oligoadenylate synthetase. Mol Cell Biol 1983. [PMID: 6865941 DOI: 10.1128/mcb.3.5.780] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report that endogenous, as well as exogenous, interferon (IFN) regulates the growth of human melanoma cells in culture. When antibodies directed against human fibroblast IFN were incorporated into the media of high-density cells stimulated to proliferate with serum, the cells entered the cell cycle earlier than did the controls. In investigating the biochemical basis for this finding, we have found that there is an inverse relationship between the (2'-5')oligoadenylate synthetase levels and the percentage of cells in S in untreated cultures. Upon IFN treatment, the relationship is obliterated and (2'-5')oligoadenylate synthetase levels increase throughout all phases of the cell cycle. This increase in enzyme levels correlates well with the decreased probability of the IFN-treated cells to cycle. These findings suggest a biological role for IFN as a negative growth factor for cells in culture.
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35
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Muñoz A, Harvey R, Carrasco L. Cellular RNA is not degraded in interferon-treated HeLa cells after poliovirus infection. FEBS Lett 1983; 160:87-92. [PMID: 6309570 DOI: 10.1016/0014-5793(83)80942-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A drastic inhibition of protein synthesis occurs in HeLa cells treated with human lymphoblastoid interferon and infected with poliovirus. At the time when this inhibition has been established no degradation of 32P-labelled ribosomal RNA can be detected. Isolation of the mRNAs from poliovirus-infected cells plus or minus interferon treatment, followed by translation in a reticulocyte lysate indicates that cellular mRNAs remain active. These results suggest that gross degradation of cellular RNA does not occur in interferon-treated poliovirus-infected HeLa cells and that a non-specific nuclease induced by 2'-5' A is not responsible for the inhibition of protein synthesis observed.
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36
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Etienne-Smekens M, Vandenbussche P, Content J, Dumont JE. (2'-5')Oligoadenylate in rat liver: modulation after partial hepatectomy. Proc Natl Acad Sci U S A 1983; 80:4609-13. [PMID: 6308630 PMCID: PMC384093 DOI: 10.1073/pnas.80.15.4609] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
(2'-5')Oligoadenylate synthetase [(2'-5')A synthetase], which synthesizes a series of oligoadenylates ppp-(A2'p)n5'A [collectively referred to as (2'-5')A], has been described previously in rat liver cells, where its concentration varied with the growth status of this organ--i.e., it decreased during the early phase of rat liver regeneration after partial hepatectomy. Because double-stranded RNA, the only known activator of this enzyme, has been detected in rat liver nuclei, (2'-5')A synthesis could occur in this tissue in vivo. Analysis of rat liver cell extract after HPLC by the endonuclease-based radiobinding assay revealed several components with retention times similar to (2'-5')A trimer- and tetramer-like material. A further characterization of these compounds by their susceptibility to alkaline phosphatase and snake venom phosphodiesterase, their resistance to micrococcal nuclease, and their ability to activate an endonuclease indicated the natural occurrence of oligonucleotides indistinguishable from authentic (2'-5')A in rat liver cells. Using the combination of the radiobinding assay and a simplified (2'-5')A extraction procedure that does not involve HPLC, we further show that the early drop of (2'-5')A synthetase activity during rat liver regeneration was accompanied by a similar decrease in intracellular (2'-5')A concentration. The three characteristic phases of the (2'-5')A synthetase kinetics during the first 40 hr of liver regeneration were mimicked by the kinetics of the synthesis of the (2'-5')A oligonucleotides themselves: between 6 and 20 hr after hepatectomy, there was a sharp decrease in (2'-5')A concentration; between 20 and 24 hr, the concentration of (2'-5')A reached a minimum; at 36 hr or after the first wave of DNA synthesis (the major event of liver regeneration), the (2'-5')A concentration returned to normal. In this characterization of the (2'-5')A oligonucleotide family in a functional tissue of an animal that had not been previously treated with interferon or infected with virus, the data are compatible with a physiological role of the (2'-5')A system acting as an intracellular component of the regulatory mechanisms leading to cell proliferation or differentiation.
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37
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Content J, De Wit L, Tavernier J, Fiers W. Human fibroblast interferon RNA transcripts of different sizes in poly(I).poly(C) induced cells. Nucleic Acids Res 1983; 11:2627-38. [PMID: 6856471 PMCID: PMC325913 DOI: 10.1093/nar/11.9.2627] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Northern blot analysis reveals that total RNA from human fibroblastoid cells (MG 63) induced with poly(I).poly(C) under conditions of IFN-beta production, contains predominantly a +/- 1,200 nucleotide long poly (A) mRNA (mRNA.M) which hybridizes with a Hu IFN-beta cDNA specific probe. But hybridization with this probe also enabled the detection of a polyadenylated RNA (RNA.I) with a length of between 3.5 kb-3.8 kb, representing 0.6% of the total hybridizable cellular RNA in superinduced cells. Mapping shows that the RNA.I contains all the sequence information present in mRNA.M. Furthermore, it also hybridizes to sequences, located downstream from the IFN-beta gene up to 2.5 kb beyond its poly A attachment site, while no hybridization to fragments located upstream of the IFN-beta mRNA cap site was observable. Hence this RNA.I corresponds to a transcript that starts at the same position as the major mRNA.M but which extends up to 2.5 kb beyond the 3'-end of mRNA.M where another polyadenylation signal is located.
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Creasey AA, Eppstein DA, Marsh YV, Khan Z, Merigan TC. Growth regulation of melanoma cells by interferon and (2'-5')oligoadenylate synthetase. Mol Cell Biol 1983; 3:780-6. [PMID: 6865941 PMCID: PMC368600 DOI: 10.1128/mcb.3.5.780-786.1983] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We report that endogenous, as well as exogenous, interferon (IFN) regulates the growth of human melanoma cells in culture. When antibodies directed against human fibroblast IFN were incorporated into the media of high-density cells stimulated to proliferate with serum, the cells entered the cell cycle earlier than did the controls. In investigating the biochemical basis for this finding, we have found that there is an inverse relationship between the (2'-5')oligoadenylate synthetase levels and the percentage of cells in S in untreated cultures. Upon IFN treatment, the relationship is obliterated and (2'-5')oligoadenylate synthetase levels increase throughout all phases of the cell cycle. This increase in enzyme levels correlates well with the decreased probability of the IFN-treated cells to cycle. These findings suggest a biological role for IFN as a negative growth factor for cells in culture.
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Abstract
Infectious leukemia virus production by two chronically infected NIH/MOL lines was strongly inhibited by interferon treatment of the cells. The corresponding degree of inhibition in JLSV-11 cells was much lower. Multiplication of encephalomyocarditis virus in all three cell lines was barely affected by interferon treatment. Replication of vesicular stomatitis virus, on the other hand, was highly sensitive to interferon in the JLSV-11 line and in one NIH/MOL line but was practically insensitive in the other NIH/MOL line. Anticellular actions of interferon were more pronounced in the JLSV-11 line than in the others. In response to interferon treatment, 2',5'-oligoadenylate synthetase activity was induced to a high level in JLSV-11 cells and to lower levels in the NIH/MOL lines. We failed to detect any 2',5'-oligoadenylate-dependent endonuclease activity in extracts of these cells. Double-stranded RNA-dependent protein kinase activity was present in extracts of interferon-treated NIH/MOL cells, but it was barely detectable in extracts of interferon-treated JLSV-11 cells. The above studies demonstrated that interferon could differentially affect the replication of three different viruses in three different cell lines, including two seemingly identical NIH/MOL lines, and that certain tentative conclusions can be drawn regarding the roles of different interferon-inducible enzyme markers in the different antiviral actions of interferons.
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Yonehara S, Yonehara-Takahashi M, Ishii A. Binding of human interferon alpha to cells of different sensitivities: studies with internally radiolabeled interferon retaining full biological activity. J Virol 1983; 45:1168-71. [PMID: 6300453 PMCID: PMC256528 DOI: 10.1128/jvi.45.3.1168-1171.1983] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The characteristics of interferon binding to various cells with different interferon sensitivity were studied by using [3H]leucine-labeled, pure human interferon alpha from Namalwa cells. Scatchard analysis of the binding data on cells sensitive to interferon alpha (human FL and fibroblasts and bovine MDBK) indicated the presence of two kinds of binding sites with high and low affinities. The binding constants of the high-affinity sites in these cells were similar (4 X 10(10) to 11 X 10(10) M-1). Cells insensitive to human interferon alpha (human HEC-1 and mouse L cells) were shown to have only low-affinity sites, suggesting that high-affinity binding sites are indispensable for interferon sensitivity and represent interferon receptors. However, the number of sites in three human diploid fibroblast strains and one strain trisomic for chromosome 21 were not proportionally correlated to the interferon sensitivity of the cells. The high-affinity binding to human cells was completely inhibited by both nonradioactive human interferons alpha and beta in a similar manner, but binding to bovine MDBK cells, on which human interferon beta is practically inactive, was inhibited effectively only by interferon alpha and not by beta. These results suggest that the receptor for human interferon alpha is common to human interferon beta in human cells, whereas the receptor on bovine cells binds only human interferon alpha.
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Morinaga N, Yonehara S, Tomita Y, Kuwata T. Insensitivity to interferon of two subclones of human endometrial carcinoma cell line, HEC-1. Int J Cancer 1983; 31:21-8. [PMID: 6299971 DOI: 10.1002/ijc.2910310105] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Two cloned cell lines, HEC-IC and HEC-ID, derived from the human endometrial adenocarcinoma cell line HEC-I, were found to be as resistant to the antiviral and anticellular activities of interferon (IFN) as were the parental cells, and 2'-5' oligoadenylate (2-5A) synthetase was not induced in these clones by IFN treatment. They were sensitive to the cytotoxicity of natural killer (NK) cells but their sensitivity was not changed by treatment of the cell lines with IFN. Binding of [3H]-leucine-labelled IFN-alpha to HEC-IC cells was examined, and Scatchard plot analysis showed that HEC-IC cells did not have any high-affinity binding sites for IFN-alpha. The cells had hyperploid chromosomes. HEC-IC had three copies of chromosome 21 while HEC-ID had only one copy of chromosome 21. The results suggest that these clones may have the structural gene for the IFN receptor but that functional receptor sites may be absent.
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Analogs of (A2'p)nA. Correlation of structure of analogs of ppp(A2'p)2A and (A2'p)2A with stability and biological activity. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)33461-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Verhaegen-Lewalle M, Content J. 2'-Phosphodiesterase activity in human cell lines treated or untreated with human interferon. EUROPEAN JOURNAL OF BIOCHEMISTRY 1982; 126:639-43. [PMID: 6183114 DOI: 10.1111/j.1432-1033.1982.tb06828.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
2'-Phosphodiesterase activity was investigated, by measuring either the disappearance of (2',5')oligo(adenylate) or the release of 5'AMP, in several human cell lines (RSa, IFr, HEC-1, WGAr and HeLa) possessing different sensitivities to interferon, and treated or untreated with human interferon. In various cell lines whose (2'-5')oligo(adenylate) synthetase was normally induced by interferon treatment, both kinetic studies and measurements at different enzyme concentrations indicated that 2'-phosphodiesterase activity remained unchanged after interferon treatment. This observation was confirmed over a broad range of substrate concentrations (1-25000 nM). The activity of 2'-phosphodiesterase was dependent on Mg(OAc)2. Our results indicate that in various human cell lines the modulation of (2'-5')oligo(adenylate) metabolism by interferon does not involve an increase of 2'-phosphodiesterase activity.
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Tomita Y, Cantell K, Kuwata T. Effects of human gamma interferon on cell growth, replication of virus and induction of 2'-5'oligoadenylate synthetase in three human lymphoblastoid cell lines and K562 cells. Int J Cancer 1982; 30:161-5. [PMID: 6182110 DOI: 10.1002/ijc.2910300206] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Human alpha interferon (IFN-alpha) and beta interferon (IFN-beta) showed antiviral and anticellular effects on human lymphoblastoid Daudi and P3HR-1 cells, but up to 1,000 units/ ml of gamma interferon (IFN-gamma) showed no such effect. Though a fairly high level of dsRNA-dependent 2'-5'-oligoadenylate synthetase (2-5A synthetase) was found in Daudi cells, treatment of these cells with IFN-alpha and beta enhanced the enzyme level in cells at least four-fold, but IFN-gamma did not show any such effect. Lymphoblastoid Raji cells were insensitive to the antiviral and anticellular activities of IFN-alpha, beta and gamma, but 2-5A synthetase was induced in cells by the treatment with IFN-alpha and beta, though the enzyme level was lower than that found in interferon-treated Daudi cells. Human leukemic K562 cells were completely insensitive to IFN-alpha, beta and at the same time to IFN-gamma with regard to the antiviral, anticellular activities and to the induction of 2-5A synthetase.
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Content J, De Wit L, Pierard D, Derynck R, De Clercq E, Fiers W. Secretory proteins induced in human fibroblasts under conditions used for the production of interferon beta. Proc Natl Acad Sci U S A 1982; 79:2768-72. [PMID: 6178110 PMCID: PMC346287 DOI: 10.1073/pnas.79.9.2768] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Human fibroblast cells treated with a combination of inhibitors of protein and RNA synthesis [cycloheximide and actinomycin D as used to superinduce interferon beta (IFN-beta)] secrete two proteins with molecular masses of 22000 and 27000 kilodaltons (called 22-kDal and 27-kDal) that are precipitable with an antiserum raised against impure IFN-beta but are antigenically distinct from IFN-beta 1. Translation in vitro of mRNA extracted from human fibroblast cells induced for the production of IFN-beta leads to the synthesis of a 26-kDal protein that is structurally closely related to the 22- and 27-kDal proteins. This 26-kDal protein mRNA is relatively abundant and also appears in human fibroblasts induced only with cycloheximide. It has been partially purified by sucrose gradient centrifugation and more extensively by diazobenzyloxymethyl-cellulose hybridization to plasmid DNA from a bacterial cDNA clone. When translated in an in vitro reticulocyte system supplemented with dog pancreas microsomes, the 26-kDal protein and two other intermediates corresponding presumably to its signal-cleaved (19-kDal) and partially glycosylated (24-kDal) forms were observed. Crude, partially purified, and highly purified 26-kDal mRNA failed to program the synthesis of antiviral or ppp(A2'p5')nA synthetase-inducing activity when translated in Xenopus laevis oocytes. Moreover, partially purified 22-kDal and 27-kDal (i.e., the in vivo equivalents of the 26-kDal protein) are also devoid of antiviral or ppp(A2'p5')nA synthetase-inducing activity. Hence, this 26-kDal mRNA, although presumably identical to the human IFN-beta 2 mRNA described by Weissenbach et al. [Weissenbach, J., Chernajovsky, Y., Zeevi, M., Shulman, K., Soreq, H., Nir. U., Wallach, D., Perricaudet, M., Tiollais, P. & Revel, M. (1980) Proc. Natl. Acad. Sci. USA 77, 7152-7156], cannot be considered to be a fibroblast interferon mRNA.
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Samuel CE, Knutson GS, Masters PS. Mechanism of interferon action: ability of cloned human type-alpha interferons to induce protein phosphorylation and inhibit virus replication is specified by the host cell rather than the interferon subspecies. JOURNAL OF INTERFERON RESEARCH 1982; 2:563-74. [PMID: 6815285 DOI: 10.1089/jir.1982.2.563] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Sen GC. Mechanism of interferon action: progress toward its understanding. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1982; 27:105-56. [PMID: 6179128 DOI: 10.1016/s0079-6603(08)60599-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Epstein DA, Czarniecki CW, Jacobsen H, Friedman RM, Panet A. A mouse cell line, which is unprotected by interferon against lytic virus infection, lacks ribonuclease F activity. EUROPEAN JOURNAL OF BIOCHEMISTRY 1981; 118:9-15. [PMID: 6169526 DOI: 10.1111/j.1432-1033.1981.tb05479.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A mouse cell line, NIH 3T3, does not respond to some of the activities of interferon. Even after treatment with high concentrations of interferon the replication of lytic viruses, such as encephalomyocarditis virus (EMCV) and vesicular stomatitis virus (VSV) is not inhibited in these cells. In contrast, interferon treatment of these same cells results in the inhibition of Moloney murine leukemia virus (MMuLV) production. We have analyzed enzymatic pathways which are induced by interferon in these cells. After interferon treatment, the level of the (2'-5')oligoadenylate [(2'-5)An] synthetase activity and the phosphorylation of the 67000-dalton protein (P1) are enhanced in NIH 3T3 cells to approximately the same level as interferon-sensitive mouse L-cells. Moreover, NIH 3T3 and L-cells, contain approximately the same levels of enzymes which inactivate (2'-5')An. Both exogenously added (2'-5')A3 or double-stranded RNA (dsRNA) failed to inhibit protein synthesis in NIH 3T3 extracts even though they were potent inhibitors of L-cell extract-directed protein synthesis. Direct measurements of the (2'-5')An-dependent ribonuclease F (RNase F) failed to detect such activity in NIH 3T3 cells. Our results, therefore, suggest that the presence of RNase F activity is necessary for the interferon-induced antiviral activity against EMCV and against VSV. The induction of protein kinase activity by interferon treatment of NIH 3T3 cells appears to have no direct effect on EMCV and VSV replication.
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Meurs E, Hovanessian AG, Montagnier L. Interferon-mediated antiviral state in human MRC5 cells in the absence of detectable levels of 2-5A synthetase and protein kinase. JOURNAL OF INTERFERON RESEARCH 1981; 1:219-32. [PMID: 6180053 DOI: 10.1089/jir.1981.1.219] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Treatment of human HeLa and MRC5 cells with human alpha (leukocyte) and beta (fibroblast) interferon results in the development of an antiviral state against two types of viruses: vesicular stomatitis virus (rhabdovirus) and encephalomyocarditis virus (picornavirus). These cells, however, differ in their ability to synthesize the two double-stranded (ds) RNA-dependent enzymatic activities, pppA(2'p5'A)n synthetase (2-5A synthetase) and protein kinase which have been reported to be induced in several cell lines by interferon. Both the 2-5A synthetase and the protein kinase are enhanced by several fold in HeLa cells on treatment with interferon. In contrast, neither the 2-5A synthetase nor the protein kinase can be detected in MRC5 cell treated or not treated with interferon. The lack of detection of the 2-5A synthetase in MRC5 cells is not associated with the absence of the other components of the 2-5A system (2-5A dependent nuclease and 2'-phosphodiesterase). We have previously shown that MRC5 cells are sensitive to the action of 2-5A and furthermore the inhibitory action of 2-5A on these cells is transient. Mixing experiments between HeLa and MRC5 cell fractions after partial purification on columns of poly(I).poly(C)-Sepharose, showed that the absence of detection of the protein kinase activity in MRC5 cells cannot be attributed to the presence of phosphatases or other inhibitors of phosphorylation in control or interferon-treated MRC5 cell extracts. In addition, we show that the interferon-mediated protein kinase activity in HeLa cell extracts can be precipitated by treatment at pH 5, a procedure which leads to an enhanced level of detectable protein kinase activity in general. Once again, however, MRC5 cell extracts fail to show any interferon-mediated protein kinase activity. These results suggest that either the two enzyme activities are not necessary for the development of the antiviral response induced by interferon or the intracellular events leading to the establishment of the antiviral state vary from one cell system to the other.
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Marti J, Vandenbussche P, Silhol M, Milhaud P, Verhaegen M, Content J, Lebleu B. Effects of interferon on sensitive and resistant L1210 cell lines. JOURNAL OF INTERFERON RESEARCH 1981; 1:287-95. [PMID: 6180059 DOI: 10.1089/jir.1981.1.287] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
L1210 cells resistant to the antiviral and anticellular effects of interferon are not inducible for the 2,5A synthetase and for the protein kinase activities. Cloning of one resistant L1210 strain has revealed heterogeneity of the cell population with respect to their antiviral and anticellular response as well as protein kinase and 2,5A synthetase inducibility. The defect in the response of truly interferon-resistant L1210 cells appears to reside at an early step of interferon action.
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