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Avila-Bonilla RG, Martínez-Montero JP. Crosstalk between vault RNAs and innate immunity. Mol Biol Rep 2024; 51:387. [PMID: 38443657 PMCID: PMC10914904 DOI: 10.1007/s11033-024-09305-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/31/2024] [Indexed: 03/07/2024]
Abstract
PURPOSE Vault (vt) RNAs are noncoding (nc) RNAs transcribed by RNA polymerase III (RNA Pol III) with 5'-triphosphate (5'-PPP) termini that play significant roles and are recognized by innate immune sensors, including retinoic acid-inducible protein 1 (RIG-I). In addition, vtRNAs adopt secondary structures that can be targets of interferon-inducible protein kinase R (PKR) and the oligoadenylate synthetase (OAS)/RNase L system, both of which are important for activating antiviral defenses. However, changes in the expression of vtRNAs have been associated with pathological processes that activate proinflammatory pathways, which influence cellular events such as differentiation, aging, autophagy, apoptosis, and drug resistance in cancer cells. RESULTS In this review, we summarized the biology of vtRNAs and focused on their interactions with the innate immune system. These findings provide insights into the diverse roles of vtRNAs and their correlation with various cellular processes to improve our understanding of their biological functions.
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Affiliation(s)
- Rodolfo Gamaliel Avila-Bonilla
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Departamento de Genética y Biología Molecular, Av. IPN 2508, 07360, Mexico City, Mexico.
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Junghare V, Alex R, Baidya A, Paul M, Alyethodi RR, Sengar GS, Kumar S, Singh U, Deb R, Hazra S. In silico modeling revealed new insights into the mechanism of action of enzyme 2'-5'-oligoadenylate synthetase in cattle. J Biomol Struct Dyn 2022; 40:14013-14026. [PMID: 34873989 DOI: 10.1080/07391102.2021.2001373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The innate immune system has an important role in developing the initial resistance to virus infection, and the ability of oligoadenylate synthetase to overcome viral evasion and enhance innate immunity is already established in humans. In the present study, we have tried to explore the molecular and structural variations present in Sahiwal (indigenous) and crossbred (Frieswal) cattle to identify the molecular mechanism of action of OAS1 gene in activation of innate immune response. The significant changes in structural alignment in terms of orientation of loops, shortening of β-sheets and formation of 3-10 α-helix was noticed in Sahiwal and Frieswal cattle. Further, it has been observed that OAS1 from Sahiwal had better binding with APC and DTP ligand than Frieswal OAS1. A remarkable change was seen in orientation at the nucleoside base region of both the ligands, which are bound with OAS1 protein from Frieswal and Sahiwal cattle. The Molecular Dynamic study of apo and ligand complex structures was provided more insight towards the stability of OAS1 from both cattle. This analysis displayed that the Sahiwal cattle protein has more steady nature throughout the simulation and has better binding towards Frieswal in terms of APC and DTP binding. Thus, OAS1 protein is the potential target for explaining the innate immune response in Sahiwal than Frieswal.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Vivek Junghare
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India
| | - Rani Alex
- ICAR-Central Institute for Research on Cattle, Meerut Cantt, India
| | - Apoorva Baidya
- Department of Chemistry, Indian Intitute of Technology Bombay, Mumbai, India
| | - Manish Paul
- Department of Biotechnology, Maharaja Sriram Chandra Bhanja Deo University, Baripada, India
| | | | | | - Sushil Kumar
- ICAR-National Research Center on Pig, Guwahati, India
| | - Umesh Singh
- ICAR-National Research Center on Pig, Guwahati, India
| | - Rajib Deb
- ICAR-National Research Center on Pig, Guwahati, India
| | - Saugata Hazra
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India.,Center of Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, India
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Abstract
Organisms throughout biology need to maintain the integrity of their genome. From bacteria to vertebrates, life has established sophisticated mechanisms to detect and eliminate foreign genetic material or to restrict its function and replication. Tremendous progress has been made in the understanding of these mechanisms which keep foreign or unwanted nucleic acids from viruses or phages in check. Mechanisms reach from restriction-modification systems and CRISPR/Cas in bacteria and archaea to RNA interference and immune sensing of nucleic acids, altogether integral parts of a system which is now appreciated as nucleic acid immunity. With inherited receptors and acquired sequence information, nucleic acid immunity comprises innate and adaptive components. Effector functions include diverse nuclease systems, intrinsic activities to directly restrict the function of foreign nucleic acids (e.g., PKR, ADAR1, IFIT1), and extrinsic pathways to alert the immune system and to elicit cytotoxic immune responses. These effects act in concert to restrict viral replication and to eliminate virus-infected cells. The principles of nucleic acid immunity are highly relevant for human disease. Besides its essential contribution to antiviral defense and restriction of endogenous retroelements, dysregulation of nucleic acid immunity can also lead to erroneous detection and response to self nucleic acids then causing sterile inflammation and autoimmunity. Even mechanisms of nucleic acid immunity which are not established in vertebrates are relevant for human disease when they are present in pathogens such as bacteria, parasites, or helminths or in pathogen-transmitting organisms such as insects. This review aims to provide an overview of the diverse mechanisms of nucleic acid immunity which mostly have been looked at separately in the past and to integrate them under the framework nucleic acid immunity as a basic principle of life, the understanding of which has great potential to advance medicine.
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Affiliation(s)
- G Hartmann
- Institute of Clinical Chemistry and Clinical Pharmacology, University Hospital, University of Bonn, Bonn, Germany.
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Gusho E, Baskar D, Banerjee S. New advances in our understanding of the "unique" RNase L in host pathogen interaction and immune signaling. Cytokine 2016; 133:153847. [PMID: 27595182 PMCID: PMC7128181 DOI: 10.1016/j.cyto.2016.08.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 08/08/2016] [Accepted: 08/08/2016] [Indexed: 12/22/2022]
Abstract
Ever since the discovery of the existence of an interferon (IFN)-regulated ribonuclease, significant advances have been made in understanding the mechanism and associated regulatory effects of its action. What had been studied initially as a "unique" endoribonuclease is currently known as ribonuclease L (RNase L where "L" stands for latent). Some of the key developments include discovery of the RNase L signaling pathway, its structural characterization, and its molecular cloning. RNase L has been implicated in antiviral and antibacterial defense, as well as in hereditary prostate cancer. RNase L is activated by 2'-5' linked oligoadenylates (2-5A), which are synthesized by the oligoadenylate synthetases (OASs), a family of IFN-regulated pathogen recognition receptors that sense double-stranded RNAs. Activated RNase L cleaves single stranded RNAs, including viral RNAs and cellular RNAs. The catalytic activity of RNase L has been found to lead into the activation of several cellular signaling pathways, including those involved in autophagy, apoptosis, IFN-β production, NLRP3 inflammasome activation leading to IL-1β secretion, inhibition of cell migration, and cell adhesion. In this review, we will highlight the newest advances in our understanding of the catalytic role of RNase L in the context of different cellular pathways and extend the scope of these findings to discussion of potential therapeutic targets for antimicrobial drug development.
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Affiliation(s)
- Elona Gusho
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue Cleveland, OH 44195, USA
| | - Danika Baskar
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue Cleveland, OH 44195, USA; Pediatrics Division Office, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA(1)
| | - Shuvojit Banerjee
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue Cleveland, OH 44195, USA.
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Ushijima H, Tsiapalis CM, Daum T, Schröder HC, Matthes E, Engels JW, Mag M, Muth J, Müller WEG. Synergistic Anti-Human Immunodeficiency Viral (HIV-1) Effect of the Immunomodulator Ampligen (Mismatched Double-Stranded RNA) with Inhibitors of Reverse Transcriptase and HIV-1 Regulatory Proteins. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/095632029300400602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The potent antiviral effect of double stranded RNA, such as the mismatched poly(l)·poly(C12U) [Ampligen], 2′,3′-dideoxy-3′-fluorothymidine (FddThd) and antisense oligodeoxynucleotides (ODN) has been established in in vitro systems using cells infected with the human immunodeficiency virus type 1 (HIV-1). We report here that the immunomodulator poly(l)·poly(C12U) interacts synergistically with (1) the reverse transcriptase inhibitor FddThd (FIC value: 0.43), (2) the modified (5′- and 3′-end capped thioates) antisense ODN-4 directed against the splice acceptor site of the HIV-1/ tat gene (FIC value: 0.66) and (3) also with pyronin Y, a compound which prevents binding of HIV-1 Rev protein to the HIV-1 RRE element. These data suggest that combinations of poly(l)·poly(C12U), a stimulator of the natural antiviral protection system of the cells, with compounds targeting HIV1-specific processes should be considered as candidate treatments of AIDS patients.
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Affiliation(s)
- H. Ushijima
- Division of AIDS Virus, AIDS Research Center, National Institute of Health, Gakuen 4-7-1, Musashimurayamashi, Tokyo 208, Japan
| | - C. M. Tsiapalis
- Division of AIDS Virus, AIDS Research Center, National Institute of Health, Gakuen 4-7-1, Musashimurayamashi, Tokyo 208, Japan
| | - T. Daum
- Institut für Physiologische Chemie, Universität, Duesbergweg 6, 55099 Mainz, Germany
| | - H. C. Schröder
- Institut für Physiologische Chemie, Universität, Duesbergweg 6, 55099 Mainz, Germany
| | - E. Matthes
- Zentralinstitut für Molekularbiologie, Robert-Rössle-Straße 10, 1115 Berlin-Buch, Germany
| | - J. W. Engels
- Institut für Organische Chemie, Universität, Niederurseier Hang, 6000 Frankfurt (M) 50, Germany
| | - M. Mag
- Institut für Organische Chemie, Universität, Niederurseier Hang, 6000 Frankfurt (M) 50, Germany
| | - J. Muth
- Institut für Organische Chemie, Universität, Niederurseier Hang, 6000 Frankfurt (M) 50, Germany
| | - W. E. G. Müller
- Institut für Physiologische Chemie, Universität, Duesbergweg 6, 55099 Mainz, Germany
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The Roles of RNase-L in Antimicrobial Immunity and the Cytoskeleton-Associated Innate Response. Int J Mol Sci 2016; 17:ijms17010074. [PMID: 26760998 PMCID: PMC4730318 DOI: 10.3390/ijms17010074] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 12/21/2015] [Accepted: 01/04/2016] [Indexed: 12/26/2022] Open
Abstract
The interferon (IFN)-regulated endoribonuclease RNase-L is involved in multiple aspects of the antimicrobial innate immune response. It is the terminal component of an RNA cleavage pathway in which dsRNA induces the production of RNase-L-activating 2-5A by the 2′-5′-oligoadenylate synthetase. The active nuclease then cleaves ssRNAs, both cellular and viral, leading to downregulation of their expression and the generation of small RNAs capable of activating retinoic acid-inducible gene-I (RIG-I)-like receptors or the nucleotide-binding oligomerization domain-like receptor 3 (NLRP3) inflammasome. This leads to IFNβ expression and IL-1β activation respectively, in addition to broader effects on immune cell function. RNase-L is also one of a growing number of innate immune components that interact with the cell cytoskeleton. It can bind to several cytoskeletal proteins, including filamin A, an actin-binding protein that collaborates with RNase-L to maintain the cellular barrier to viral entry. This antiviral activity is independent of catalytic function, a unique mechanism for RNase-L. We also describe here the interaction of RNase-L with the E3 ubiquitin ligase and scaffolding protein, ligand of nump protein X (LNX), a regulator of tight junction proteins. In order to better understand the significance and context of these novel binding partners in the antimicrobial response, other innate immune protein interactions with the cytoskeleton are also discussed.
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Brennan-Laun SE, Ezelle HJ, Li XL, Hassel BA. RNase-L control of cellular mRNAs: roles in biologic functions and mechanisms of substrate targeting. J Interferon Cytokine Res 2015; 34:275-88. [PMID: 24697205 DOI: 10.1089/jir.2013.0147] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
RNase-L is a mediator of type 1 interferon-induced antiviral activity that has diverse and critical cellular roles, including the regulation of cell proliferation, differentiation, senescence and apoptosis, tumorigenesis, and the control of the innate immune response. Although RNase-L was originally shown to mediate the endonucleolytic cleavage of both viral and ribosomal RNAs in response to infection, more recent evidence indicates that RNase-L also functions in the regulation of cellular mRNAs as an important mechanism by which it exerts its diverse biological functions. Despite this growing body of work, many questions remain regarding the roles of mRNAs as RNase-L substrates. This review will survey known and putative mRNA substrates of RNase-L, propose mechanisms by which it may selectively cleave these transcripts, and postulate future clinical applications.
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Affiliation(s)
- Sarah E Brennan-Laun
- 1 Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine , Baltimore, Maryland
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Li MMH, MacDonald MR, Rice CM. To translate, or not to translate: viral and host mRNA regulation by interferon-stimulated genes. Trends Cell Biol 2015; 25:320-9. [PMID: 25748385 PMCID: PMC4441850 DOI: 10.1016/j.tcb.2015.02.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Revised: 01/28/2015] [Accepted: 02/05/2015] [Indexed: 01/08/2023]
Abstract
Translational regulation of viral and host mRNA is an important function of a subset of interferon-stimulated genes (ISGs). These ISGs repress translation through binding to viral RNA, direct interaction with, or perturbation of the translation machinery components. Several ISGs localize to cytoplasmic granules such as stress granules (SGs) and processing bodies (PBs), and interfere with the processing or function of microRNAs (miRNAs).
Type I interferon (IFN) is one of the first lines of cellular defense against viral pathogens. As a result of IFN signaling, a wide array of IFN-stimulated gene (ISG) products is upregulated to target different stages of the viral life cycle. We review recent findings implicating a subset of ISGs in translational regulation of viral and host mRNAs. Translation inhibition is mediated either by binding to viral RNA or by disrupting physiological interactions or levels of the translation complex components. In addition, many of these ISGs localize to translationally silent cytoplasmic granules, such as stress granules and processing bodies, and intersect with the microRNA (miRNA)-mediated silencing pathway to regulate translation of cellular mRNAs.
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Affiliation(s)
- Melody M H Li
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA.
| | - Margaret R MacDonald
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, The Rockefeller University, New York, NY, USA
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9
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Abstract
My Ph.D. thesis in the laboratory of Severo Ochoa at New York University School of Medicine in 1962 included the determination of the nucleotide compositions of codons specifying amino acids. The experiments were based on the use of random copolyribonucleotides (synthesized by polynucleotide phosphorylase) as messenger RNA in a cell-free protein-synthesizing system. At Yale University, where I joined the faculty, my co-workers and I first studied the mechanisms of protein synthesis. Thereafter, we explored the interferons (IFNs), which were discovered as antiviral defense agents but were revealed to be components of a highly complex multifunctional system. We isolated pure IFNs and characterized IFN-activated genes, the proteins they encode, and their functions. We concentrated on a cluster of IFN-activated genes, the p200 cluster, which arose by repeated gene duplications and which encodes a large family of highly multifunctional proteins. For example, the murine protein p204 can be activated in numerous tissues by distinct transcription factors. It modulates cell proliferation and the differentiation of a variety of tissues by binding to many proteins. p204 also inhibits the activities of wild-type Ras proteins and Ras oncoproteins.
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Affiliation(s)
- Peter Lengyel
- From the Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06520
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10
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Kranzusch PJ, Lee ASY, Berger JM, Doudna JA. Structure of human cGAS reveals a conserved family of second-messenger enzymes in innate immunity. Cell Rep 2013; 3:1362-8. [PMID: 23707061 PMCID: PMC3800681 DOI: 10.1016/j.celrep.2013.05.008] [Citation(s) in RCA: 269] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Accepted: 05/09/2013] [Indexed: 12/13/2022] Open
Abstract
Innate immune recognition of foreign nucleic acids induces protective interferon responses. Detection of cytosolic DNA triggers downstream immune signaling through activation of cyclic GMP-AMP synthase (cGAS). We report here the crystal structure of human cGAS, revealing an unanticipated zinc-ribbon DNA-binding domain appended to a core enzymatic nucleotidyltransferase scaffold. The catalytic core of cGAS is structurally homologous to the RNA-sensing enzyme, 2'-5' oligo-adenylate synthase (OAS), and divergent C-terminal domains account for specific ligand-activation requirements of each enzyme. We show that the cGAS zinc ribbon is essential for STING-dependent induction of the interferon response and that conserved amino acids displayed within the intervening loops are required for efficient cytosolic DNA recognition. These results demonstrate that cGAS and OAS define a family of innate immunity sensors and that structural divergence from a core nucleotidyltransferase enables second-messenger responses to distinct foreign nucleic acids.
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Affiliation(s)
- Philip J. Kranzusch
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720 USA
| | - Amy Si-Ying Lee
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720 USA
- Center for RNA Systems Biology, University of California, Berkeley, CA 94720 USA
| | - James M. Berger
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720 USA
| | - Jennifer A. Doudna
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720 USA
- Center for RNA Systems Biology, University of California, Berkeley, CA 94720 USA
- Department of Chemistry, University of California, Berkeley, CA 94720 USA
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Howard Hughes Medical Institute (HHMI), University of California, Berkeley, CA 94720 USA
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Differential impact of interferon regulatory factor 7 in initiation of the type I interferon response in the lymphocytic choriomeningitis virus-infected central nervous system versus the periphery. J Virol 2012; 86:7384-92. [PMID: 22514347 DOI: 10.1128/jvi.07090-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Interferon (IFN) regulatory factors (IRFs) are a family of transcription factors involved in regulating type I IFN genes and other genes participating in the early antiviral host response. To better understand the mechanisms involved in virus-induced central nervous system (CNS) inflammation, we studied the influence of IRF1, -3, -7, and -9 on the transcriptional activity of key genes encoding antiviral host factors in the CNS of mice infected with lymphocytic choriomeningitis virus (LCMV). A key finding is that neither IRF3 nor IRF7 is absolutely required for induction of a type I IFN response in the LCMV-infected CNS, whereas concurrent elimination of both factors markedly reduces the virus-induced host response. This is unlike the situation in the periphery, where deficiency of IRF7 almost eliminates the LCMV-induced production of the type I IFNs. This difference is seemingly related to the local environment, as peripheral production of type I IFNs is severely reduced in intracerebrally (i.c.) infected IRF7-deficient mice, which undergo a combined infection of the CNS and peripheral organs, such as spleen and lymph nodes. Interestingly, despite the redundancy of IRF7 in initiating the type I IFN response in the CNS, the response is not abolished in IFN-β-deficient mice, as might have been expected. Collectively, these data demonstrate that the early type I IFN response to LCMV infection in the CNS is controlled by a concerted action of IRF3 and -7. Consequently this work provides strong evidence for differential regulation of the type I IFN response in the CNS versus the periphery during viral infection.
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Interactions Between Rnase L Ankyrin-Like Domain and ABC Transporters as a Possible Origin for Pain, Ion Transport, CNS and Immune Disorders of Chronic Fatigue Immune Dysfunction Syndrome. ACTA ACUST UNITED AC 2011. [DOI: 10.1300/j092v08n03_08] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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13
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Hong LZ, Li J, Schmidt-Küntzel A, Warren WC, Barsh GS. Digital gene expression for non-model organisms. Genome Res 2011; 21:1905-15. [PMID: 21844123 DOI: 10.1101/gr.122135.111] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Next-generation sequencing technologies offer new approaches for global measurements of gene expression but are mostly limited to organisms for which a high-quality assembled reference genome sequence is available. We present a method for gene expression profiling called EDGE, or EcoP15I-tagged Digital Gene Expression, based on ultra-high-throughput sequencing of 27-bp cDNA fragments that uniquely tag the corresponding gene, thereby allowing direct quantification of transcript abundance. We show that EDGE is capable of assaying for expression in >99% of genes in the genome and achieves saturation after 6-8 million reads. EDGE exhibits very little technical noise, reveals a large (10(6)) dynamic range of gene expression, and is particularly suited for quantification of transcript abundance in non-model organisms where a high-quality annotated genome is not available. In a direct comparison with RNA-seq, both methods provide similar assessments of relative transcript abundance, but EDGE does better at detecting gene expression differences for poorly expressed genes and does not exhibit transcript length bias. Applying EDGE to laboratory mice, we show that a loss-of-function mutation in the melanocortin 1 receptor (Mc1r), recognized as a Mendelian determinant of yellow hair color in many different mammals, also causes reduced expression of genes involved in the interferon response. To illustrate the application of EDGE to a non-model organism, we examine skin biopsy samples from a cheetah (Acinonyx jubatus) and identify genes likely to control differences in the color of spotted versus non-spotted regions.
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Affiliation(s)
- Lewis Z Hong
- Department of Genetics, Stanford University, Stanford, California 94305, USA
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Inhibition of 2',5'-oligoadenylate synthetase expression and function by the human cytomegalovirus ORF94 gene product. J Virol 2011; 85:5696-700. [PMID: 21450824 DOI: 10.1128/jvi.02463-10] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human cytomegalovirus (HCMV) ORF94 gene product has been reported to be expressed during both productive and latent phases of infection, although its function is unknown. We report that expression of pORF94 leads to decreased 2',5'-oligoadenylate synthetase (OAS) expression in transfected cells with and without interferon stimulation. Furthermore, the functional activity of OAS was inhibited by pORF94. Finally, we present evidence of OAS modulation by pORF94 during productive HCMV infection of human fibroblasts. This study provides the first identification of a function for pORF94 and identifies an additional means by which HCMV may limit a critical host cell antiviral response.
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Kristiansen H, Gad HH, Eskildsen-Larsen S, Despres P, Hartmann R. The oligoadenylate synthetase family: an ancient protein family with multiple antiviral activities. J Interferon Cytokine Res 2010; 31:41-7. [PMID: 21142819 DOI: 10.1089/jir.2010.0107] [Citation(s) in RCA: 217] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The 2'-5' oligoadenylate synthetases (OAS) are interferon-induced antiviral enzymes that recognize virally produced dsRNA and initiate RNA destabilization through activation of RNase L within infected cells. However, recent evidence points toward several RNase L-independent pathways, through which members of the OAS family can exert antiviral activity. The crystal structure of OAS led to a novel insight into the catalytic mechanism, and revealed a remarkable similarity between OAS, Polyadenosine polymerase, and the class I CCA-adding enzyme from Archeoglobus fulgidus. This, combined with a variety of bioinformatic data, leads to the definition of a superfamily of template independent polymerases and proved that the OAS family are ancient proteins, which probably arose as early as the beginning of metazoan evolution.
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Affiliation(s)
- Helle Kristiansen
- Centre for Structural Biology, Department of Molecular Biology, Aarhus University, Aarhus, Denmark
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Visser GM, Tromp M, van Westrenen J, Schipperus O, van Boom JH. Synthesis of some modified 2′-5′-linked oligoriboadenylates of 2-5A core. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19861050303] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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17
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Rios JJ, Fleming JGW, Bryant UK, Carter CN, Huber JC, Long MT, Spencer TE, Adelson DL. OAS1 polymorphisms are associated with susceptibility to West Nile encephalitis in horses. PLoS One 2010; 5:e10537. [PMID: 20479874 PMCID: PMC2866329 DOI: 10.1371/journal.pone.0010537] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Accepted: 04/18/2010] [Indexed: 12/13/2022] Open
Abstract
West Nile virus, first identified within the United States in 1999, has since spread across the continental states and infected birds, humans and domestic animals, resulting in numerous deaths. Previous studies in mice identified the Oas1b gene, a member of the OAS/RNASEL innate immune system, as a determining factor for resistance to West Nile virus (WNV) infection. A recent case-control association study described mutations of human OAS1 associated with clinical susceptibility to WNV infection. Similar studies in horses, a particularly susceptible species, have been lacking, in part, because of the difficulty in collecting populations sufficiently homogenous in their infection and disease states. The equine OAS gene cluster most closely resembles the human cluster, with single copies of OAS1, OAS3 and OAS2 in the same orientation. With naturally occurring susceptible and resistant sub-populations to lethal West Nile encephalitis, we undertook a case-control association study to investigate whether, similar to humans (OAS1) and mice (Oas1b), equine OAS1 plays a role in resistance to severe WNV infection. We identified naturally occurring single nucleotide mutations in equine (Equus caballus) OAS1 and RNASEL genes and, using Fisher's Exact test, we provide evidence that mutations in equine OAS1 contribute to host susceptibility. Virtually all of the associated OAS1 polymorphisms were located within the interferon-inducible promoter, suggesting that differences in OAS1 gene expression may determine the host's ability to resist clinical manifestations associated with WNV infection.
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Affiliation(s)
- Jonathan J. Rios
- McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - JoAnn G. W. Fleming
- Department of Animal Science, Texas A&M University, College Station, Texas, United States of America
| | - Uneeda K. Bryant
- Livestock Disease Diagnostic Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Craig N. Carter
- Livestock Disease Diagnostic Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - John C. Huber
- School of Rural Public Health, Texas A&M University, College Station, Texas, United States of America
| | - Maureen T. Long
- College of Veterinary Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Thomas E. Spencer
- Department of Animal Science, Texas A&M University, College Station, Texas, United States of America
| | - David L. Adelson
- School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, South Australia, Australia
- * E-mail:
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Bisbal C, Salehzada T. [RNase L, a crucial mediator of innate immunity and other cell functions]. Med Sci (Paris) 2009; 24:859-64. [PMID: 18950583 DOI: 10.1051/medsci/20082410859] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The 2-5A/RNase L pathway is one of the first cellular defences against viruses. RNase L is an unusual endoribonuclease which activity is strictly regulated by its binding to a small oligonucleotide, 2-5A. 2-5A itself is very unusual, consisting of a series of 5'- triphosphorylated oligoadenylates with 2'-5' bonds. But RNase L activity is not limited to viral RNA cleavage. RNase L plays a central role in innate immunity, apoptosis, cell growth and differentiation by regulating cellular RNA stability and expression. Default in its activity leads to increased susceptibility to virus infections and to tumor development. RNase L gene has been identified as HPC1 (Hereditary Prostate Cancer 1) gene. Study of RNase L variant R462Q in etiology of prostate cancer has led to the identification of the novel human retrovirus closely related to xenotropic murine leukemia viruses (MuLVs) and named XMRV.
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Affiliation(s)
- Catherine Bisbal
- Inserm ERI25-EA 4202, Muscle et Pathologies, Bâtiment Crastes de Paulet, CHU Arnaud de Villeneuve, 371, avenue du Doyen Gaston Giraud, 34295 Montpellier Cedex 5, France.
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Preparation of (2′-5′)-oligonucleotides based on 6-N-benzylaminopurineriboside using the Spicaria violacea fungal enzyme complex. Chem Nat Compd 2009. [DOI: 10.1007/s10600-009-9249-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lengyel P. From RNase L to the Multitalented p200 Family Proteins: An Exploration of the Modes of Interferon Action. J Interferon Cytokine Res 2008; 28:273-81. [DOI: 10.1089/jir.2008.3993.hp] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Peter Lengyel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
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Rios JJ, Perelygin AA, Long MT, Lear TL, Zharkikh AA, Brinton MA, Adelson DL. Characterization of the equine 2'-5' oligoadenylate synthetase 1 (OAS1) and ribonuclease L (RNASEL) innate immunity genes. BMC Genomics 2007; 8:313. [PMID: 17822564 PMCID: PMC2048516 DOI: 10.1186/1471-2164-8-313] [Citation(s) in RCA: 13] [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: 03/21/2007] [Accepted: 09/07/2007] [Indexed: 11/13/2022] Open
Abstract
Background The mammalian OAS/RNASEL pathway plays an important role in antiviral host defense. A premature stop-codon within the murine Oas1b gene results in the increased susceptibility of mice to a number of flaviviruses, including West Nile virus (WNV). Mutations in either the OAS1 or RNASEL genes may also modulate the outcome of WNV-induced disease or other viral infections in horses. Polymorphisms in the human OAS gene cluster have been previously utilized for case-control analysis of virus-induced disease in humans. No polymorphisms have yet been identified in either the equine OAS1 or RNASEL genes for use in similar case-control studies. Results Genomic sequence for equine OAS1 was obtained from a contig assembly generated from a shotgun subclone library of CHORI-241 BAC 100I10. Specific amplification of regions of the OAS1 gene from 13 horses of various breeds identified 33 single nucleotide polymorphisms (SNP) and two microsatellites. RNASEL cDNA sequences were determined for 8 mammals and utilized in a phylogenetic analysis. The chromosomal location of the RNASEL gene was assigned by FISH to ECA5p17-p16 using two selected CHORI-241 BAC clones. The horse genomic RNASEL sequence was assembled. Specific amplification of regions of the RNASEL gene from 13 horses identified 31 SNPs. Conclusion In this report, two dinucleotide microsatellites and 64 single nucleotide polymorphisms within the equine OAS1 and RNASEL genes were identified. These polymorphisms are the first to be reported for these genes and will facilitate future case-control studies of horse susceptibility to infectious diseases.
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Affiliation(s)
- Jonathan J Rios
- Department of Animal Science, Texas A&M University, 2471 TAMU, College Station, Texas 77843, USA
| | - Andrey A Perelygin
- Biology Department, Georgia State University, 24 Peachtree Center Ave., Atlanta, Georgia 30302, USA
| | - Maureen T Long
- College of Veterinary Medicine, University of Florida, 2015 SW 16th Ave., Gainesville, Florida 32608, USA
| | - Teri L Lear
- Department of Veterinary Science, University of Kentucky, 108 Maxwell H. Gluck Equine Research Center, Lexington, Kentucky, 40546, USA
| | - Andrey A Zharkikh
- Bioinformatics Department, Myriad Genetics, Inc., 320 Wakara Way, Salt Lake City, UT, 84108, USA
| | - Margo A Brinton
- Biology Department, Georgia State University, 24 Peachtree Center Ave., Atlanta, Georgia 30302, USA
| | - David L Adelson
- School of Molecular and Biomedical Science, University of Adelaide, SA 5005, Australia
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Hovanessian AG. On the discovery of interferon-inducible, double-stranded RNA activated enzymes: the 2'-5'oligoadenylate synthetases and the protein kinase PKR. Cytokine Growth Factor Rev 2007; 18:351-61. [PMID: 17681872 DOI: 10.1016/j.cytogfr.2007.06.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The demonstration that double-stranded (ds) RNA inhibits protein synthesis in cell-free systems prepared from interferon-treated cells, lead to the discovery of the two interferon-induced, dsRNA-dependent enzymes: the serine/threonine protein kinase that is referred to as PKR and the 2',5'-oligoadenylate synthetase (2',5'-OAS), which converts ATP to 2',5'-linked oligoadenylates with the unusual 2'-5' instead of 3'-5' phosphodiesterase bond. We raised monoclonal and polyclonal antibodies against human PKR and the two larger forms of the 2',5'-OAS. Such specific antibodies proved to be indispensable for the detailed characterization of these enzyme and the cloning of cDNAs corresponding to the human PKR and the 69-71 and 100 kDa forms of the 2',5'-OAS. When activated by dsRNA, PKR becomes autophosphorylated and catalyzes phosphorylation of the protein synthesis initiation factor eIF2, whereas the 2'-5'OAS forms 2',5'-oligoadenylates that activate the latent endoribonuclease, the RNAse L. By inhibiting initiation of protein synthesis or by degrading RNA, these enzymes play key roles in two independent pathways that regulate overall protein synthesis and the mechanism of the antiviral action of interferon. In addition, these enzymes are now shown to regulate other cellular events, such as gene induction, normal control of cell growth, differentiation and apoptosis.
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Affiliation(s)
- Ara G Hovanessian
- UPR 2228 CNRS, UFR Biomédicale - Université René Descartes, 45 rue des Saints Pères, 75270 Paris Cedex 06, France.
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Abstract
The antiviral and antitumor actions of interferons are caused, in part, by a remarkable regulated RNA cleavage pathway known as the 2-5A/RNase L system. 2'-5' linked oligoadenylates (2-5A) are produced from ATP by interferon-inducible synthetases. 2-5A activates pre-existing RNase L, resulting in the cleavage of RNAs within single-stranded regions. Activation of RNase L by 2-5A leads to an antiviral response, although precisely how this happens is a subject of ongoing investigations. Recently, RNase L was identified as the hereditary prostate cancer 1 gene. That finding has led to the discovery of a novel human retrovirus, XMRV. My scientific journey through the 2-5A system recounts some of the highlights of these efforts. Knowledge gained from studies on the 2-5A system could have an impact on development of therapies for important viral pathogens and cancer.
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Affiliation(s)
- Robert H Silverman
- Department of Cancer Biology, NB40 Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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24
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Chemical enzymatic synthesis of (2′-5′)-oligoadenylates using nuclease from Spicaria violacea mycelial fungus. Chem Nat Compd 2007. [DOI: 10.1007/s10600-007-0095-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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25
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Bisbal C, Silverman RH. Diverse functions of RNase L and implications in pathology. Biochimie 2007; 89:789-98. [PMID: 17400356 PMCID: PMC2706398 DOI: 10.1016/j.biochi.2007.02.006] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Accepted: 02/06/2007] [Indexed: 01/16/2023]
Abstract
The endoribonuclease L (RNase L) is the effector of the 2-5A system, a major enzymatic pathway involved in the molecular mechanism of interferons (IFNs). RNase L is a very unusual nuclease with a complex mechanism of regulation. It is a latent enzyme, expressed in nearly every mammalian cell type. Its activation requires its binding to a small oligonucleotide, 2-5A. 2-5A is a series of unique 5'-triphosphorylated oligoadenylates with 2'-5' phosphodiester bonds. By regulating viral and cellular RNA expression, RNase L plays an important role in the antiviral and antiproliferative activities of IFN and contributes to innate immunity and cell metabolism. The 2-5A/RNase L pathway is implicated in mediating apoptosis in response to viral infections and to several types of external stimuli. Several recent studies have suggested that RNase L could have a role in cancer biology and evidence of a tumor suppressor function of RNase L has emerged from studies on the genetics of hereditary prostate cancer.
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Affiliation(s)
- Catherine Bisbal
- IGH UPR CNRS 1142. 141 rue de la Cardonille. 34396. Montpellier France. E-mail address: , Phone: 33 (0)4 99 61 99 73, Fax: 33 (0)4 99 61 99 01
| | - Robert H. Silverman
- Department of Cancer Biology, Lerner Research Institute, 9500 Euclid Avenue NB40, Cleveland Clinic, Cleveland OH 44195 USA, E-mail address: , Phone: (1) 216 445 9650, Fax: (1) 216 445 6269
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Hovanessian AG, Justesen J. The human 2'-5'oligoadenylate synthetase family: unique interferon-inducible enzymes catalyzing 2'-5' instead of 3'-5' phosphodiester bond formation. Biochimie 2007; 89:779-88. [PMID: 17408844 DOI: 10.1016/j.biochi.2007.02.003] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 02/06/2007] [Indexed: 01/13/2023]
Abstract
The demonstration by Kerr and colleagues that double-stranded (ds) RNA inhibits drastically protein synthesis in cell-free systems prepared from interferon-treated cells, suggested the existence of an interferon-induced enzyme, which is dependent on dsRNA. Consequently, two distinct dsRNA-dependent enzymes were discovered: a serine/threonine protein kinase that nowadays is referred to as PKR and a 2'-5'oligoadenylate synthetase (2'-5'OAS) that polymerizes ATP to 2'-5'-linked oligomers of adenosine with the general formula pppA(2'p5'A)(n), n>or=1. The product is pppG2'p5'G when GTP is used as a substrate. Three distinct forms of 2'-5'OAS exist in human cells, small, medium, and large, which contain one, two, and three OAS units, respectively, and are encoded by distinct genes clustered on the 2'-5'OAS locus on human chromosome 12. OASL is an OAS like IFN-induced protein encoded by a gene located about 8 Mb telomeric from the 2'-5'OAS locus. OASL is composed of one OAS unit fused at its C-terminus with two ubiquitin-like repeats. The human OASL is devoid of the typical 2'-5'OAS catalytic activity. In addition to these structural differences between the various OAS proteins, the three forms of 2'-5'OAS are characterized by different subcellular locations and enzymatic parameters. These findings illustrate the apparent structural and functional complexity of the human 2'-5'OAS family, and suggest that these proteins may have distinct roles in the cell.
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Affiliation(s)
- Ara G Hovanessian
- UPR 2228 CNRS, UFR Biomédicale, Université René Descartes, 45 rue des Saints Pères, 75270 Paris Cedex 06, France.
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Cayley PJ, Brown RE, Kerr IM. High-Performance Liquid Chromatography of 2′-5′Oligoadenylates and Related Oligonucleotides. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/01483918208067615] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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28
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Itkes AV, Severin ES. Regulation of the 2',5'-oligoadenylate system by cyclic adenosine monophosphate-dependent phosphorylation. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 59:213-40. [PMID: 3028055 DOI: 10.1002/9780470123058.ch5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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29
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Charubala R, Uhlmann E, Pfleiderer W. Nucleotide, XVI. Synthese und Eigenschaften von Adenylyl-adenylyl-adenosinen. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/jlac.198119811223] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Uno T, Hirabayashi K, Murai M, Yano J, Ozato K. The role of IFN regulatory factor-3 in the cytotoxic activity of NS-9, a polyinosinic-polycytidylic acid/cationic liposome complex, against tumor cells. Mol Cancer Ther 2005; 4:799-805. [PMID: 15897244 DOI: 10.1158/1535-7163.mct-04-0317] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
NS-9 is a complex of polyinosinic-polycytidylic acid and a novel cationic liposome, LIC-101. The complex has strong cytotoxic activity against tumor cells derived from epithelial or fibroblastic cells. We have investigated the mechanism of the cytotoxic activity of NS-9 using knockdown cells in which the expression of proteins of interest was inhibited by RNA interference. NS-9 showed strong cytotoxic activity against knockdown cells with reduced expression of double-stranded RNA-dependent protein kinase, RNase L, or IFN-alpha/beta receptor, but showed no cytotoxic activity against IFN regulatory factor-3 (IRF3) knockdown cells. In IRF3-knockdown cells, NS-9 also did not induce either the DNA fragmentation or the rRNA degradation observed in negative control cells. We conclude that IRF3 plays a crucial role in the cytotoxic activity of NS-9 against tumor cells, whereas RNA-dependent protein kinase, RNase L, or type I IFNs are not important for its activity.
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Affiliation(s)
- Tomonori Uno
- Discovery Research Laboratories, Nippon Shinyaku Co., Ltd., 14 Nishinosho-Monguchi-cho, Kisshoin, Minami, Kyoto 601-8550, Japan.
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31
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Kimchi A, Shure H, Revel M. Anti-mitogenic function of interferon-induced (2'-5')oligo(adenylate) and growth-related variations in enzymes that synthesize and degrade this oligonucleotide. EUROPEAN JOURNAL OF BIOCHEMISTRY 2005; 114:5-10. [PMID: 6163628 DOI: 10.1111/j.1432-1033.1981.tb06163.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Addition of (2'5')ApApA to concanavalin-A-stimulated mouse spleen lymphocytes strongly inhibits the large increase in RNA and protein synthesis which takes place 24-48 h after stimulation. The inhibitory effect on protein synthesis precedes the effect on RNA synthesis and takes at least 6 h to be detected. Histone synthesis is preferentially inhibited at 48 h. No effect on protein synthesis was detected in unstimulated resting lymphocytes, or in stimulated lymphocytes during the first 24 h after concanavalin A treatment. The anti-mitogenic effect of the (2'-5')oligo(adenylate) seems to result, therefore, from inhibition of protein synthesis taking place before initiation of DNA replication. The mitogenic stimulus produced by the lectin enhances, in lymphocytes, the level of the 2'-phosphodiesterase which degrades (2'-5')oligo(adenylate). Enhancement of the 2'-phosphodiesterase was also observed after serum stimulation of confluent monkey kidney cells. Furthermore, the ratio of (2'-5')oligo(adenylate) synthetase to 2'-phosphodiesterase is ten-times lower in fast-growing kidney cells than in quiescent serum-starved cells. A model for the role of (2'-5')oligo(adenylate) synthesis and degradation in the regulation of cell proliferation by interferon and by mitogens is presented.
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32
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Andersen JB, Strandbygård DJ, Hartmann R, Justesen J. Interaction between the 2'-5' oligoadenylate synthetase-like protein p59 OASL and the transcriptional repressor methyl CpG-binding protein 1. ACTA ACUST UNITED AC 2004; 271:628-36. [PMID: 14728690 DOI: 10.1046/j.1432-1033.2003.03966.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The human 2'-5' oligoadenylate synthetases (OAS) form a conserved family of interferon-induced proteins consisting of four genes: OAS1, OAS2, OAS3 and the 2'-5' oligoadenylate synthetase-like gene (OASL). When activated by double-stranded RNA, OAS1-3 polymerize ATP into 2'-5'-linked oligoadenylates; 2'-5'-linked oligoadenylates, in turn, activate a latent endoribonuclease that degrades viral and cellular RNAs. In contrast, while the p59 OASL protein is highly homologous to the OAS family (45% identity), its 350 amino acid N-terminal domain lacks 2'-5' oligoadenylate synthetase activity. A C-terminal 164 amino acid domain, which is 30% homologous to a tandem repeat of ubiquitin, further distinguishes the p59 OASL protein and suggests that it serves a biological role which is distinct from other OAS family members. To dissect the function of p59 OASL, we utilized the yeast two-hybrid system to identify interacting proteins. Methyl CpG-binding protein 1 (MBD1), which functions as a transcriptional repressor, was identified as a strong p59 OASL interactor. Interestingly, like p59 OASL, transcription of the MBD1 gene was induced by interferon, indicating that these genes are co-ordinately regulated. The interaction was confirmed in vitro and in vivo and was mapped to the ubiquitin-like domain of p59 OASL. The p59 OASL-MBD1 interaction was specific, because p59 OASL did not interact with any of the other MBD family members and MBD1 did not interact with OAS1. These findings link the p59 OASL with MBD1 transcriptional control in the context of an interferon-stimulated cell, and provide the basis for future studies to examine the functional role of this interaction.
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Affiliation(s)
- Jesper B Andersen
- Department of Molecular Biology (MBI), University of Aarhus, Denmark
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33
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Inhibition of host protein synthesis and degradation of cellular mRNAs during infection by influenza and herpes simplex virus. Mol Cell Biol 2003. [PMID: 14582206 DOI: 10.1128/mcb.2.12.1644] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cloned DNA copies of two cellular genes were used to monitor, by blot hybridization, the stability of particular cell mRNAs after infection by influenza virus and herpesvirus. The results indicated that the inhibition of host cell protein synthesis that accompanied infection by each virus could be explained by a reduction in the amounts of cellular mRNAs in the cytoplasm, and they suggested that this decrease was due to virus-mediated mRNA degradation.
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Inglis SC. Inhibition of host protein synthesis and degradation of cellular mRNAs during infection by influenza and herpes simplex virus. Mol Cell Biol 2003; 2:1644-8. [PMID: 14582206 PMCID: PMC369973 DOI: 10.1128/mcb.2.12.1644-1648.1982] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cloned DNA copies of two cellular genes were used to monitor, by blot hybridization, the stability of particular cell mRNAs after infection by influenza virus and herpesvirus. The results indicated that the inhibition of host cell protein synthesis that accompanied infection by each virus could be explained by a reduction in the amounts of cellular mRNAs in the cytoplasm, and they suggested that this decrease was due to virus-mediated mRNA degradation.
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Affiliation(s)
- S C Inglis
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 2QQ, England
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35
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Boyle KA, Pietropaolo RL, Compton T. Engagement of the cellular receptor for glycoprotein B of human cytomegalovirus activates the interferon-responsive pathway. Mol Cell Biol 1999; 19:3607-13. [PMID: 10207084 PMCID: PMC84158 DOI: 10.1128/mcb.19.5.3607] [Citation(s) in RCA: 167] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/1998] [Accepted: 02/02/1999] [Indexed: 11/20/2022] Open
Abstract
Cells respond to contact with human cytomegalovirus (HCMV) virions by initiating intracellular signaling and gene expression characteristic of the interferon (IFN)-responsive pathway. Herein, we demonstrate that a principal mechanism of HCMV-induced signal transduction is via an interaction of the primary viral ligand, glycoprotein B (gB), with its cellular receptor. Cells incubated with a purified, soluble form of gB resulted in the transcriptional upregulation of IFN-responsive genes OAS and ISG54 (encoding 2'-5' oligoadenylate synthetase and an IFN-stimulated gene product of 54 kDa) to a comparable level as virions or IFN. Gene induction was an immediate and direct response to gB which did not require de novo protein synthesis. Neither the initial virus attachment site, heparan sulfate proteoglycans, nor the IFN-alpha/beta or IFN-gamma receptors are involved in the response. Pleotropic protein phosphorylation was required for cellular gene induction, and the mitogen-activated protein kinases ERK1 and ERK2 were activated in response to the ligand. Together these data indicate that a principal means by which cytomegalovirus induces intracellular signaling and activation of the interferon-responsive pathway is via an interaction of gB with an as yet unidentified, likely novel cellular receptor that interfaces with the IFN signaling pathway.
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Affiliation(s)
- K A Boyle
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin 53706-1532, USA
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Rebouillat D, Hovanessian AG. The human 2',5'-oligoadenylate synthetase family: interferon-induced proteins with unique enzymatic properties. J Interferon Cytokine Res 1999; 19:295-308. [PMID: 10334380 DOI: 10.1089/107999099313992] [Citation(s) in RCA: 179] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
2',5'-Oligoadenylate synthetase (2',5'-OAS) was discovered and characterized as an interferon (IFN)-induced enzyme that in the presence of double-stranded (ds) RNA converts ATP into 2',5'-linked oligomers of adenosine with the general formula pppA(2'p'A)n, n > or = 1. The product is pppG2'p5'G when GTP is used as a substrate. Now, 20 years later, this activity is attributed to several well-characterized, homologous, and IFN-induced proteins in human cells. Three distinct forms of 2',5'-OAS exist, small, medium, and large, which contain 1, 2, and 3 OAS units, respectively, and are encoded by distinct genes clustered on the 2',5'-OAS locus on human chromosome 12. Recently, other IFN-induced proteins homologous to the OAS unit but devoid of the typical 2',5'-OAS catalytic activity have been described. These OAS-related proteins are encoded by a gene located at the proximity of the 2',5'-OAS locus. These findings illustrate the apparent structural and functional complexity of the human 2',5'-OAS family.
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Affiliation(s)
- D Rebouillat
- Institut Pasteur, Unité de Virologie et Immunologie Cellulaire, URA CNRS 1930, Paris, France
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Hartmann R, Olsen HS, Widder S, Jorgensen R, Justesen J. p59OASL, a 2'-5' oligoadenylate synthetase like protein: a novel human gene related to the 2'-5' oligoadenylate synthetase family. Nucleic Acids Res 1998; 26:4121-8. [PMID: 9722630 PMCID: PMC147837 DOI: 10.1093/nar/26.18.4121] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The 2'-5' oligoadenylate synthetases form a well conserved family of interferon induced proteins, presumably present throughout the mammalian class. Using the Expressed Sequence Tag databases, we have identified a novel member of this family. This protein, which we named p59 2'-5' oligoadenylate synthetase-like protein (p59OASL), shares a highly conserved N-terminal domain with the known forms of 2'-5' oligoadenylate synthetases, but differs completely in its C-terminal part. The C-terminus of p59OASL is formed of two domains of ubiquitin-like sequences. Here we present the characterisation of a full-length cDNA clone, the genomic sequence and the expression pattern of this gene. We have addressed the evolution of the 2'-5' oligoadenylate synthetase gene family, in the light of both this new member and new 2'-5' oligoadenylate synthetase sequence data from other species, which have recently appeared in the databases.
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Affiliation(s)
- R Hartmann
- Department of Molecular and Structural Biology, University of Aarhus, C. F. Mollers allé Building 130, DK-8000 Aarhus C, Denmark and Human Genome Sciences Inc., 9410 Key West Avenue, Rockville, MD 20850, USA
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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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Bisbal C. RNase L: effector nuclease of an activatable RNA degradation system in mammals. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 1997; 18:19-34. [PMID: 8994259 DOI: 10.1007/978-3-642-60471-3_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- C Bisbal
- IGMM CNRS UMR 5535, Montpellier, France
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Marin JG, Mencia-Huerta JM, Braquet P, Chabrier PE. Involvement of interleukin-6 and interferon-alpha in the poly(A).Poly(U)-induced 2',5'-oligoadenylate synthetase activity in the mouse monocyte-macrophage cell line, J774A1. J Interferon Cytokine Res 1996; 16:251-7. [PMID: 8697148 DOI: 10.1089/jir.1996.16.251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The synthetic polyribonucleotide poly(A).poly(U) induces 2',5'-oligoadenylate synthetase activity in the murine macrophage cell line J774A1. The possible role of several cytokines involved in macrophage activation (i.e., IL-1, IL-6, TNF, and IFN) was examined in the present study. It was first demonstrated that among the anticytokine antibodies, only monoclonal antibodies directed against IL-6 inhibited the induction of 2',5'-oligoadenylate synthetase by poly(A).poly(U) in a dose-dependent manner. Moreover, it was established that poly(A).poly(U) elicited IL-6 production in J774A1 cells in a time-and dose-dependent manner. Consequently, the effect of IL-6 on 2',5'-oligoadenylate synthetase activity was studied. IL-6 either alone or in combination with IL-1 and TNF did not induce 2',5'-oligoadenylate synthetase activity. IL-6 did not potentiate IFN-gamma-induced 2'-5'-oligoadenylate synthetase activity. In contrast, addition of IL-6 to the incubation medium potentiated the stimulation of 2'-5'-oligoadenylate synthetase activity by IFN-alpha. These results suggest that IL-6 is a necessary but not sufficient factor in the induction of 2'-5'-oligoadenylate synthetase activity in the J774A1 cell line by poly(A).poly(U).
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Affiliation(s)
- J G Marin
- Institut Henri Beaufour, Les Ulis, France
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Bayard B, Bette-Bobillo P, Aliau S. Affinity purification and characterization of (2'-5')oligo(adenylate)-dependent RNase from mouse spleen. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 223:403-10. [PMID: 8055909 DOI: 10.1111/j.1432-1033.1994.tb19007.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Murine (2'-5')An-dependent RNase, a key enzyme of the interferon system, was purified from mouse spleen by affinity chromatography to immobilized (2'-5')An. Since the ribonuclease has high affinity to (2'-5')An, optimal non-denaturing conditions were obtained to disrupt the (2'-5')An-nuclease complex. Low-pH buffers in the presence of 0.1% Triton X-100 removed almost 80% of the enzyme from the (2'-5')An-agarose, preserving its (2'-5')An binding activity and RNA cleavage function. Purification was monitored using a classical radiobinding assay, ultraviolet covalent crosslinking method and denaturing-renaturing affinity blotting assay. The purified enzyme was a 160-kDa dimer that migrated with an apparent molecular mass of 78 kDa and was > 80% pure, as assessed by silver-stained SDS gels. Both a 160-kDa dimer and 78-kDa monomer were found in the cellular extract at a 5:1 ratio. Binding of radiolabeled (2'-5')An to (2'-5')An-dependent RNase either in crude extract or in purified form reached equilibrium by 5 h at 4 degrees C. 2-Mercaptoethanol was required to obtain (2-'5')An-binding activity but, interestingly, in the absence of this reducing agent, (2'-5')An-binding activity was initiated by preincubation with poly(U), a synthetic substrate of the nuclease. This new mechanistic feature indicates that interaction of poly(U) with nuclease induced a conformational modification allowing, in a second step, the binding of (2'-5')An. Furthermore, when activated by low amounts of (2'-5')An, the eluted purified enzyme degraded mRNA but there was still degradation in the absence of (2'-5')An. This suggested a loss of regulatory protein(s) during the purification step. Scatchard analysis showed that the purified enzyme had a Kd of 106 pM for (2'-5')An, similar to estimates obtained using crude spleen extracts (Kd 112 pM), indicating that the purified nuclease had almost identical (2'-5')An-binding properties to those identified in spleen extracts.
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Affiliation(s)
- B Bayard
- CNRS U.R.A. 530, Université Montpellier II-Sciences et Techniques du Languedoc, France
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Silverman RH. Fascination with 2-5A-dependent RNase: a unique enzyme that functions in interferon action. JOURNAL OF INTERFERON RESEARCH 1994; 14:101-4. [PMID: 7523539 DOI: 10.1089/jir.1994.14.101] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Interferon (IFN) treatment of cells results in the induction of 2-5A-synthetases, double-stranded RNA-activated enzymes that produce unusual 5'-phosphorylated 2',5'-linked oligoadenylates known as 2-5A. 2.5A activates a unique IFN-induced endoribonuclease, the 2-5A-dependent RNase (RNase L), that is capable of degrading both viral and cellular RNA. The expression cloning of 2-5A-dependent RNase is leading to meaningful analysis of the physiological functions of the 2-5A system. For example, expression in mouse cells of a dominant-negative mutant form of 2-5A-dependent RNase suppressed both the antiencephalomyocarditis virus and anticellular activities of IFN. Future investigations into this intriguing ribonuclease pathway promise to provide an intricate view into a molecular pathway of IFN action.
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Affiliation(s)
- R H Silverman
- Research Institute, Cleveland Clinic Foundation, OH 44122
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Schröder HC, Kelve M, Schäcke H, Pfleiderer W, Charubala R, Suhadolnik RJ, Müller WE. Inhibition of DNA topoisomerase I activity by 2',5'-oligoadenylates and mismatched double-stranded RNA in uninfected and HIV-1-infected H9 cells. Chem Biol Interact 1994; 90:169-83. [PMID: 8156606 DOI: 10.1016/0009-2797(94)90101-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
2',5'-Oligoadenylates (2-5As) inhibit the type I DNA topoisomerase activity both in uninfected and HIV-1-infected human T cell line H9 as well as the purified enzyme (calf thymus). Topoisomerase I activity was determined by measuring the relaxation of negatively supercoiled pBR322 DNA. Inhibition of topoisomerase I by 2-5A depends on the chain length of the oligomer and the presence of 5'-phosphate. The 5'-triphosphate of the 2-5A hexamer was most active (almost total inhibition of DNA relaxation at 10 microM concentration); the 2-5A core trimer (at 100 microM) displayed no significant effect. In crosslinking and immunoprecipitation experiments we present evidence that 2-5A (32P-labelled 2-5A derivative, ppp(A2'p)3 A[32P]pCp) is able to bind to nuclear topoisomerase I. The mismatched dsRNA, poly(I).poly(C12U) (Ampligen), exhibited a strong anti-HIV-1 activity. However, our data show that this antiviral effect is not related to topoisomerase I inhibition. On the other hand, we did observe the production of longer oligomers of 2-5A in cells treated with poly(I).poly(C12U). It remains speculative, whether the in vivo effect could be catalyzed by this activity of poly(I).poly(C12U). In addition we could show that 2-5A also inhibits topoisomerase I activity associated with isolated HIV-1 particles.
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Affiliation(s)
- H C Schröder
- Abteilung Angewandte Molekularbiologie, Johannes Gutenberg-Universität, Mainz, Germany
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Müller WE, Ushijima H, Schröder HC. Mechanism of the antiretroviral effect of dsRNA. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 1994; 14:66-88. [PMID: 7914807 DOI: 10.1007/978-3-642-78549-8_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- W E Müller
- Institut für Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Johannes Gutenberg-Universität, Mainz, Germany
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Schröder HC, Kelve M, Müller WE. The 2-5A system and HIV infection. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 1994; 14:176-97. [PMID: 7914804 DOI: 10.1007/978-3-642-78549-8_10] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
2',5'-Oligoadenylates (2-5A) have an essential role in the establishment of the antiviral state of a cell exposed to virus infection. The key enzymes of the 2-5A system are the 2-5A forming 2',5'-oligoadenylate synthetase (2-5OAS), the activity of which depends on the presence of viral or cellular double-stranded RNA (dsRNA), and the 2-5A-activated ribonuclease (RNase L). Basic research in recent years has shown that the 2-5A system is a promising target for anti-HIV chemotherapy, particularly due to its interaction with double-stranded segments within HIV RNA. Two new strategies have been developed which yield a selective antiviral effect of 2-5A against HIV-1 infection: (1) development of 2-5A analogues displaying a dual mode of action (activation of RNase L and inhibition of HIV-1 RT) and (2) intracellular immunization of cells against HIV-1 infection by application of the HIV-1-LTR--2-5OAS hybrid gene. A further strategy is the inhibition of DNA topoisomerase I by longer 2-5A oligomers.
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Affiliation(s)
- H C Schröder
- Abteilung Angewandte Molekularbiologie, Johannes Gutenberg-Universität, Mainz, Germany
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Affiliation(s)
- N Fujii
- Department of Microbiology, Sapporo Medical College, Hokkaido, Japan
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Ushijima H, Rytik PG, Schäcke H, Scheffer U, Müller WE, Schröder HC. Mode of action of the anti-AIDS compound poly(I).poly(C12U) (Ampligen): activator of 2',5'-oligoadenylate synthetase and double-stranded RNA-dependent kinase. JOURNAL OF INTERFERON RESEARCH 1993; 13:161-71. [PMID: 8099601 DOI: 10.1089/jir.1993.13.161] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The mismatched double-stranded RNA (dsRNA), poly(I).poly(C12U), also termed Ampligen, exhibits a strong antiviral and cytoprotective effect on cells (human T-lymphoblastoid CEM cells and human T-cell line H9) infected with the human immunodeficiency virus type 1 (HIV-1). Untreated H9 cells infected with HIV-1 start to release the virus 3 days post-infection, while in the presence of 40 micrograms/ml (80 micrograms/ml) of poly(I).poly(C12U) the onset of virus production and release is retarded and does not occur before day 5 (day 6). We demonstrate that poly(I).poly(C12U) markedly extends the duration of the transient increase of 2',5'-oligoadenylate (2-5A) synthetase mRNA level and activity preceding virus production after infection of cells with HIV-1. Treatment of HeLa cells with poly(I).poly(C12U) was found to cause a significant increase in total (activated plus latent) 2-5A synthetase activity; no evidence was obtained that the level of latent (nonactivated) 2-5A synthetase is changed in cells treated with dsRNA plus interferon (IFN). Poly(I).poly(C12U) is able to bind and to activate 2-5A synthetase(s) from HeLa cell extracts. Addition of poly(I).poly(C12U) to HeLa cell extracts results in production of longer 2-5A oligomers (> or = 3 adenylate residues), which are better activators of RNase L. Both free and immobilized poly(I).poly(C12U) also bind to the dsRNA-dependent protein kinase (p68 kinase), resulting in autophosphorylation of the enzyme. Activation of the kinase by the free RNA occurs within a limited concentration range (10(-7) to 10(-6) grams/ml). Addition of HIV-1 Tat protein does not affect binding and activation of p68 kinase to poly(I).poly(C12U)-cellulose but strongly reduces the binding of the kinase to immobilized TAR RNA of HIV-1. We conclude that poly(I).poly(C12U) may antagonize Tat-mediated down-regulation of dsRNA-dependent enzymes.
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Affiliation(s)
- H Ushijima
- Division of AIDS Virus, AIDS Research Center, National Institute of Health, Tokyo, Japan
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Zhang GY, Beltchev B, Fournier A, Zhang YH, Malassiné A, Bisbal C, Ehresmann B, Ehresmann C, Darlix JL, Thang MN. High levels of 2',5'-oligoadenylate synthetase and 2',5'-oligoadenylate-dependent endonuclease in human trophoblast. AIDS Res Hum Retroviruses 1993; 9:189-96. [PMID: 8457385 DOI: 10.1089/aid.1993.9.189] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Human placenta contains a high level of 2',5'-oligoadenylate (2-5A) synthetase activity of the 100-kD form of the enzyme. About 20% of the placental 2-5A synthetase activity was found to be cytosolic, whereas the remaining 80% was released by 0.5 M KCl in the presence of detergent. Most of the enzyme activity was localized in trophoblast cells, which also contain a high level of 2-5A-dependent RNase L activity. The purified trophoblast 100-kD 2-5A synthetase was shown to be activated by human immunodeficiency virus type 1 (HIV-1) 5' RNA 1-311 and 1-707, which both contain the TAR and primer binding site (PBS) structured regions. These two HIV-1 RNAs activated human trophoblast 2-5A synthetase at the same level as poly(I).poly (C), a standard highly efficient activator of the enzyme, and at the same optimal concentration. On the contrary, HIV-1 RNA 311-618, a poorly structured region missing TAR and PBS, was shown to be a poor activator of the enzyme. The specific cellular location of the 2-5A synthetase and its efficient activation by HIV 5' RNA favors the idea that the trophoblast 2-5A system negatively controls HIV replication in trophoblasts.
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Barber GN, Tomita J, Garfinkel MS, Meurs E, Hovanessian A, Katze MG. Detection of protein kinase homologues and viral RNA-binding domains utilizing polyclonal antiserum prepared against a baculovirus-expressed ds RNA-activated 68,000-Da protein kinase. Virology 1992; 191:670-9. [PMID: 1360180 DOI: 10.1016/0042-6822(92)90242-h] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The P68 protein kinase (referred to as P68 based on its M(r) of 68,000 in human cells) is a serine/threonine kinase induced by interferon treatment and activated by dsRNAs. The kinase is under tight controls in virus-infected cells since once activated, it phosphorylates its natural substrate eukaryotic initiation factor 2 (elF-2), leading to potential limitations in functional elF-2 and decreases in protein synthesis initiation. To further delineate the molecular mechanisms underlying kinase regulation, we attempted to express the P68 protein kinase in insect cells using a baculovirus vector. Repeated efforts to isolate recombinant baculoviruses containing a wild-type kinase failed, whereas recombinants expressing a nonfunctional kinase with a catalytic domain II mutation were readily isolated. When used to infect Spodoptera frugiperda cells, the recombinant virus expressed the exogenous mutant protein at almost 5-10% of the total proteins synthesized. We then purified the kinase by immunoaffinity chromatography to raise monospecific antiserum which recognized not only the human native wild-type P68, but also kinase homologues in murine, bovine, and monkey cells as determined by immunoblot and immunoprecipitation analysis. Fortunately, kinase function also could be assayed using this antibody since the human and nonhuman kinase homologues, present in immunoprecipitates, were autophosphorylated and phosphorylated the natural substrate, elF-2 alpha. Further, this antiserum recognized epitopes throughout the molecule including the amino and carboxyl termini in contrast to the available monoclonal antibody. In vitro assays using the polyclonal antibody revealed the importance of the amino terminus, especially amino acids 1-97, in the binding of the kinase to viral RNA activators and inhibitors. Finally, we determined that the P68 amino terminus was both necessary and sufficient for binding dsRNA as we were able to transfer dsRNA-binding properties to a reporter gene product previously unable to bind RNA.
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Affiliation(s)
- G N Barber
- Department of Microbiology, School of Medicine, University of Washington, Seattle 98195
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Haines D, Suhadolnik R, Hubbell H, Gillespie D. Cellular and enzymatic activities of a synthetic heteropolymer double-stranded RNA of defined size. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)36962-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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