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Chaumont L, Collet B, Boudinot P. Protein kinase double-stranded RNA-dependent (PKR) in antiviral defence in fish and mammals. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 145:104732. [PMID: 37172664 DOI: 10.1016/j.dci.2023.104732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/07/2023] [Accepted: 05/09/2023] [Indexed: 05/15/2023]
Abstract
The interferon-inducible double-stranded RNA-dependent protein kinase (PKR) is one of the key antiviral arms of the innate immune system. Upon binding of viral double stranded RNA, a viral Pattern Associated Molecular Pattern (PAMP), PKR gets activated and phosphorylates the eukaryotic initiation factor 2α (eIF2α) resulting in a protein shut-down that limits viral replication. Since its discovery in the mid-seventies, PKR has been shown to be involved in multiple important cellular processes including apoptosis, proinflammatory and innate immune responses. Viral subversion mechanisms of PKR underline its importance in the antiviral response of the host. PKR activation pathways and its mechanisms of action were previously identified and characterised mostly in mammalian models. However, fish Pkr and fish-specific paralogue Z-DNA-dependent protein kinase (Pkz) also play key role in antiviral defence. This review gives an update on the current knowledge on fish Pkr/Pkz, their conditions of activation and their implication in the immune responses to viruses, in comparison to their mammalian counterparts.
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Affiliation(s)
- Lise Chaumont
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, 78350, France
| | - Bertrand Collet
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, 78350, France
| | - Pierre Boudinot
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, 78350, France.
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2
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Gan Z, Xu X, Tang S, Wen Q, Jin Y, Lu Y. Identification and functional characterization of protein kinase R (PKR) in amphibian Xenopus tropicalis. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 141:104648. [PMID: 36708793 DOI: 10.1016/j.dci.2023.104648] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 01/09/2023] [Accepted: 01/24/2023] [Indexed: 06/18/2023]
Abstract
As one of interferon-induced serine/threonine kinases, the protein kinase R (PKR) plays vital roles in antiviral defense, and functional features of PKR remain largely unknown in amphibians, which suffer from ranaviral diseases in the last few decades. In this study, a PKR gene named Xt-PKR was characterized in the Western clawed frog (Xenopus tropicalis). Xt-PKR gene was widely expressed in different organs/tissues, and was rapidly induced by poly(I:C) in spleen, kidney, and liver. Intriguingly, Xt-PKR could be up-rugulated by the treatment of type I and type III interferons, and the transcript level of Xt-PKR induced by type I interferon was much higher than that of type III interferon. Moreover, overexpression of Xt-PKR can suppress the protein synthesis and ranavirus replication in vitro, and the residue lysine required for the translation inhibition activity in mammalian PKR is conserved in Xt-PKR. The present study represents the first characterization on the functions of amphibian PKR, and reveals considerable functional conservation of PKR in early tetrapods.
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Affiliation(s)
- Zhen Gan
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institute, College of Fishery, Guangdong Ocean University, Zhanjiang, 524088, China.
| | - Xinlan Xu
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institute, College of Fishery, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Shaoshuai Tang
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China
| | - Qingqing Wen
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institute, College of Fishery, Guangdong Ocean University, Zhanjiang, 524088, China
| | - Yong Jin
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China
| | - Yishan Lu
- Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institute, College of Fishery, Guangdong Ocean University, Zhanjiang, 524088, China.
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Susceptibility and Permissivity of Zebrafish (Danio rerio) Larvae to Cypriniviruses. Viruses 2023; 15:v15030768. [PMID: 36992477 PMCID: PMC10051318 DOI: 10.3390/v15030768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/19/2023] Open
Abstract
The zebrafish (Danio rerio) represents an increasingly important model organism in virology. We evaluated its utility in the study of economically important viruses from the genus Cyprinivirus (anguillid herpesvirus 1, cyprinid herpesvirus 2 and cyprinid herpesvirus 3 (CyHV-3)). This revealed that zebrafish larvae were not susceptible to these viruses after immersion in contaminated water, but that infections could be established using artificial infection models in vitro (zebrafish cell lines) and in vivo (microinjection of larvae). However, infections were transient, with rapid viral clearance associated with apoptosis-like death of infected cells. Transcriptomic analysis of CyHV-3-infected larvae revealed upregulation of interferon-stimulated genes, in particular those encoding nucleic acid sensors, mediators of programmed cell death and related genes. It was notable that uncharacterized non-coding RNA genes and retrotransposons were also among those most upregulated. CRISPR/Cas9 knockout of the zebrafish gene encoding protein kinase R (PKR) and a related gene encoding a protein kinase containing Z-DNA binding domains (PKZ) had no impact on CyHV-3 clearance in larvae. Our study strongly supports the importance of innate immunity-virus interactions in the adaptation of cypriniviruses to their natural hosts. It also highlights the potential of the CyHV-3-zebrafish model, versus the CyHV-3-carp model, for study of these interactions.
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Jacquet S, Culbertson M, Zhang C, El Filali A, De La Myre Mory C, Pons JB, Filippi-Codaccioni O, Lauterbur ME, Ngoubangoye B, Duhayer J, Verez C, Park C, Dahoui C, Carey CM, Brennan G, Enard D, Cimarelli A, Rothenburg S, Elde NC, Pontier D, Etienne L. Adaptive duplication and genetic diversification of protein kinase R contribute to the specificity of bat-virus interactions. SCIENCE ADVANCES 2022; 8:eadd7540. [PMID: 36417524 PMCID: PMC9683710 DOI: 10.1126/sciadv.add7540] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 10/05/2022] [Indexed: 05/29/2023]
Abstract
Several bat species act as asymptomatic reservoirs for many viruses that are highly pathogenic in other mammals. Here, we have characterized the functional diversification of the protein kinase R (PKR), a major antiviral innate defense system. Our data indicate that PKR has evolved under positive selection and has undergone repeated genomic duplications in bats in contrast to all studied mammals that have a single copy of the gene. Functional testing of the relationship between PKR and poxvirus antagonists revealed how an evolutionary conflict with ancient pathogenic poxviruses has shaped a specific bat host-virus interface. We determined that duplicated PKRs of the Myotis species have undergone genetic diversification, allowing them to collectively escape from and enhance the control of DNA and RNA viruses. These findings suggest that viral-driven adaptations in PKR contribute to modern virus-bat interactions and may account for bat-specific immunity.
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Affiliation(s)
- Stéphanie Jacquet
- Laboratoire de Biométrie et Biologie Evolutive (LBBE), UMR 5558, UCBL1, CNRS, Lyon, France
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
| | - Michelle Culbertson
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Chi Zhang
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Adil El Filali
- Laboratoire de Biométrie et Biologie Evolutive (LBBE), UMR 5558, UCBL1, CNRS, Lyon, France
| | - Clément De La Myre Mory
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
| | - Jean-Baptiste Pons
- Laboratoire de Biométrie et Biologie Evolutive (LBBE), UMR 5558, UCBL1, CNRS, Lyon, France
| | | | - M. Elise Lauterbur
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Barthélémy Ngoubangoye
- International Centre of Medical Research of Franceville, Primatology Centre, Franceville, Gabon
| | - Jeanne Duhayer
- Laboratoire de Biométrie et Biologie Evolutive (LBBE), UMR 5558, UCBL1, CNRS, Lyon, France
| | - Clément Verez
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
| | - Chorong Park
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Clara Dahoui
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
| | - Clayton M. Carey
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Greg Brennan
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - David Enard
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
| | - Andrea Cimarelli
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
| | - Stefan Rothenburg
- Department of Medical Microbiology and Immunology, School of Medicine, University of California Davis, Davis, CA 95616, USA
| | - Nels C. Elde
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, MD 20815, USA
| | - Dominique Pontier
- Laboratoire de Biométrie et Biologie Evolutive (LBBE), UMR 5558, UCBL1, CNRS, Lyon, France
| | - Lucie Etienne
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, F-69007 Lyon, France
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eIF2α Phosphorylation in Response to Nutritional Deficiency and Stressors in the Aquaculture Fish, Rachycentron canadum. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2022. [DOI: 10.3390/jmse10050709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study investigates the response of the marine fish cobia, Rachycentron canadum, to stressors as measured by phosphorylation of the α-subunit of the translational initiation factor, eIF2. eIF2α is the target of phosphorylation by a family of kinases that respond to a range of physiological stressors. Phosphorylation of eIF2α inhibits overall protein synthesis, but also facilitates the reprogramming of gene expression to adapt to, and recover from, stress. The deduced coding sequence of cobia eIF2α has 94% identity to both zebrafish (Danio rerio) and human eIF2α sequences with identical phosphorylation and kinase docking sites. Here we use cobia larvae and a cobia cell line derived from muscle (Cm cells) to investigate the response of cobia eIF2α to various stressors. In Cm cells, phosphorylation of eIF2α is increased by nutrient deficiency and endoplasmic reticulum stress (ER stress), consistent with the activation of the eIF2 kinases, GCN2, and PERK. In cobia juveniles, diet and water temperature affect the phosphorylation state of eIF2α. We conclude that evaluation of eIF2α phosphorylation could function as an early marker to evaluate diet, environmental stressors, and disease in cobia and may be of particular use in optimizing conditions for rearing cobia larvae and juveniles.
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Gan Z, Cheng J, Hou J, Chen S, Xia H, Xia L, Kwok KWH, Lu Y, Nie P. Tilapia dsRNA-activated protein kinase R (PKR): An interferon-induced antiviral effector with translation inhibition activity. FISH & SHELLFISH IMMUNOLOGY 2021; 112:74-80. [PMID: 33667675 DOI: 10.1016/j.fsi.2021.02.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 02/21/2021] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
The dsRNA-activated protein kinase R (PKR) is one of key antiviral effectors induced by interferons (IFNs), and its functions are largely unknown in tilapia, an important commercial fish species suffering from several viral infectious diseases. In the present study, a PKR gene named On-PKR was identified and cloned from Nile tilapia, Oreochromis niloticus. On-PKR gene was constitutively expressed in all tissues examined, with the highest expression level observed in head kidney and liver, and was rapidly induced in all organs/tissues tested following the stimulation of poly(I:C). Importantly, the expression of On-PKR is induced by group I and group II IFNs with distinct induction kinetics in vivo: group I IFN elicits a relative delayed but sustained induction of On-PKR, whereas group II IFN triggers a rapid and transient expression of On-PKR. Moreover, the overexpression of On-PKR has been proven to inhibit the protein translation and virus replication in fish cells. The present study thus contributes to a better understanding of the functions of antiviral effectors in tilapia, and may provide clues for the prevention and therapy of viral diseases in fish.
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Affiliation(s)
- Zhen Gan
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, And Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen, 518120, China
| | - Jun Cheng
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China; College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, And Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen, 518120, China
| | - Jing Hou
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China
| | - Shannan Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Hongli Xia
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China
| | - Liqun Xia
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China; College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, And Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen, 518120, China
| | - Kevin W H Kwok
- Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hong Kong, China
| | - Yishan Lu
- Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, China; College of Fishery, Guangdong Ocean University, Zhanjiang, 524025, China; Guangdong Provincial Engineering Research Center for Aquatic Animal Health Assessment, And Shenzhen Public Service Platform for Evaluation of Marine Economic Animal Seedings, Shenzhen, 518120, China.
| | - Pin Nie
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
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Chiang DC, Li Y, Ng SK. The Role of the Z-DNA Binding Domain in Innate Immunity and Stress Granules. Front Immunol 2021; 11:625504. [PMID: 33613567 PMCID: PMC7886975 DOI: 10.3389/fimmu.2020.625504] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 12/21/2020] [Indexed: 12/18/2022] Open
Abstract
Both DNA and RNA can maintain left-handed double helical Z-conformation under physiological condition, but only when stabilized by Z-DNA binding domain (ZDBD). After initial discovery in RNA editing enzyme ADAR1, ZDBD has also been described in pathogen-sensing proteins ZBP1 and PKZ in host, as well as virulence proteins E3L and ORF112 in viruses. The host-virus antagonism immediately highlights the importance of ZDBD in antiviral innate immunity. Furthermore, Z-RNA binding has been shown to be responsible for the localization of these ZDBD-containing proteins to cytoplasmic stress granules that play central role in coordinating cellular response to stresses. This review sought to consolidate current understanding of Z-RNA sensing in innate immunity and implore possible roles of Z-RNA binding within cytoplasmic stress granules.
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Affiliation(s)
- De Chen Chiang
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, Malaysia
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Gelugor, Malaysia
| | - Yan Li
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Siew Kit Ng
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, Malaysia
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
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8
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Cytosolic Sensors for Pathogenic Viral and Bacterial Nucleic Acids in Fish. Int J Mol Sci 2020; 21:ijms21197289. [PMID: 33023222 PMCID: PMC7582293 DOI: 10.3390/ijms21197289] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 09/29/2020] [Indexed: 12/11/2022] Open
Abstract
Recognition of the non-self signature of invading pathogens is a crucial step for the initiation of the innate immune mechanisms of the host. The host response to viral and bacterial infection involves sets of pattern recognition receptors (PRRs), which bind evolutionarily conserved pathogen structures, known as pathogen-associated molecular patterns (PAMPs). Recent advances in the identification of different types of PRRs in teleost fish revealed a number of cytosolic sensors for recognition of viral and bacterial nucleic acids. These are DExD/H-box RNA helicases including a group of well-characterized retinoic acid inducible gene I (RIG-I)-like receptors (RLRs) and non-RLR DExD/H-box RNA helicases (e.g., DDX1, DDX3, DHX9, DDX21, DHX36 and DDX41) both involved in recognition of viral RNAs. Another group of PRRs includes cytosolic DNA sensors (CDSs), such as cGAS and LSm14A involved in recognition of viral and intracellular bacterial dsDNAs. Moreover, dsRNA-sensing protein kinase R (PKR), which has a role in antiviral immune responses in higher vertebrates, has been identified in fish. Additionally, fish possess a novel PKR-like protein kinase containing Z-DNA binding domain, known as PKZ. Here, we review the current knowledge concerning cytosolic sensors for recognition of viral and bacterial nucleic acids in teleosts.
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Wei J, Zang S, Li C, Zhang X, Gao P, Qin Q. Grouper PKR activation inhibits red-spotted grouper nervous necrosis virus (RGNNV) replication in infected cells. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 111:103744. [PMID: 32442443 DOI: 10.1016/j.dci.2020.103744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/10/2020] [Accepted: 05/09/2020] [Indexed: 06/11/2023]
Abstract
The double-stranded RNA-activated protein kinase (PKR) is a Type I interferon (IFN) stimulated gene that has important biological and immunological functions. In viral infections, PKR inhibits or promotes viral replication. In the present study, PKR homologues of orange-spotted grouper (Epinephelus coioides) (EcPKR) were cloned and the involvement of EcPKR during Red-spotted grouper nervous necrosis virus (RGNNV) infection was investigated. EcPKR encodes a 621-amino acid polypeptide that is closely related to the equivalent protein in Larimichthys crocea. EcPKR encoded two dsRNA binding domains and a Serine/Threonine protein kinase domain. Quantitative real-time PCR (qRT-PCR) analysis indicated that EcPKR was present in all examined tissues, with higher expression in spleen, intestine and gill. When stimulated with poly(I:C), the expression of EcPKR in the grouper spleen was increased, with highest expression 12 h post stimulation. EcPKR concentration was significantly increased in RGNNV-infected cells, with highest expression at 36 h post stimulation. EcPKR is mainly present in the cytoplasm. Overexpression of EcPKR in grouper spleen (GS) cells inhibits the transcription of the RGNNV genes. Furthermore, our results show that EcPKR overexpression significantly enhances the immune response of interferon and the activation of interferon-beta (IFN-β), interferon stimulated response element (ISRE) and nuclear factor-kappa B (NF-κB). Taken together, these results are important for better understanding of the function of PKR in fish and reveal its involvement in host response to immune challenges in RGNNV.
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Affiliation(s)
- Jingguang Wei
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Shaoqing Zang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Qingdao, 266000, China; State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266000, China; CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Chen Li
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Xin Zhang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Pin Gao
- State Key Laboratory Breeding Base for Sustainable Exploitation of Tropical Biotic Resources, College of Marine Science, Hainan University, Haikou, 570228, China
| | - Qiwei Qin
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China; Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266000, China.
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10
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Hu Z, Du H, Lin G, Han K, Cheng X, Feng Z, Mao H, Hu C. Grass carp (Ctenopharyngodon idella) PACT induces cell apoptosis and activates NF-кB via PKR. FISH & SHELLFISH IMMUNOLOGY 2020; 103:377-384. [PMID: 32454210 DOI: 10.1016/j.fsi.2020.05.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/17/2020] [Accepted: 05/12/2020] [Indexed: 06/11/2023]
Abstract
As a dsRNA-dependent and interferon-induced protein kinase, PKR is involved in antiviral immune response and apoptosis mediated by various cytokines. In mammalian cells, PKR can also be activated in the absence of dsRNA. A PKR activator, PACT (PKR activating protein), also referred to as RAX (PKR-associated protein X) plays an important role. In recent years, with the increasing recognition of fish interferon system, PKR and PACT have been gradually revealed in fish. However, the function of fish PACT is unclear. In our previous work, we suggested that grass carp (Ctenopharyngodon idella) PACT must be involved in IRF2 and ATF4-mediated stress response pathways. In the present study, we found that the expression of C. idella PACT (CiPACT) and CiPKR were significantly up-regulated under the stimulation of LPS. It indicated that CiPACT and CiPKR may play an important role in response to LPS stimulation. In addition, the response time of CiPACT to LPS is earlier than that of CiPKR. It has also shown that overexpression of CiPACT in CIK cells can significantly enhance the level of p-eIF2α, induces apoptosis and translocation of Cip65 to nucleus from cytoplasm. To further understand the mechanism, we carried out the co-immunoprecipitation assay. It proved that the interaction of CiPACT and CiPKR made the phosphorylation of CiPKR. Overexpression of CiPACT induced the down-regulation of intracellular expression of bcl-2 and up-regulation of bax. However, in CiPKR knocked-down cells the expression of bcl-2 and bax were just the opposite. Therefore, the mechanism of fish PACT induces apoptosis and activates NF-кB is dependent on PKR.
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Affiliation(s)
- Zhizhen Hu
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Hailing Du
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Gang Lin
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Kun Han
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Xining Cheng
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Zhiqing Feng
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Huiling Mao
- School of Life Science, Nanchang University, Nanchang, 330031, China
| | - Chengyu Hu
- School of Life Science, Nanchang University, Nanchang, 330031, China.
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Wu C, Zhang Y, Hu C. PKZ, a Fish-Unique eIF2α Kinase Involved in Innate Immune Response. Front Immunol 2020; 11:585. [PMID: 32296447 PMCID: PMC7137213 DOI: 10.3389/fimmu.2020.00585] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/13/2020] [Indexed: 12/12/2022] Open
Abstract
PKZ is a novel and unique eIF2α protein kinase identified in fish. Although PKZ is most homologous to PKR, particularly in the C-terminal catalytic domain, it contains two N-terminal Z-DNA-binding domains (Zα1 and Zα2) instead of the dsRNA binding domains (dsRBDs) in PKR. As a novel member of eIF2α kinase family, the available data suggest that PKZ has some distinct mechanisms for recognition, binding, and B-Z DNA transition. Functionally, PKZ seems to be activated by the binding of Zα to Z-DNA and participates in innate immune responses. In this review, we summarize the recent progress on fish PKZ.
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Affiliation(s)
- Chuxin Wu
- Department of Natural Sciences, Yuzhang Normal University, Nanchang, China
| | - Yibing Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Chengyu Hu
- Department of Bioscience, College of Life Sciences, Nanchang University, Nanchang, China
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12
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Levraud JP, Jouneau L, Briolat V, Laghi V, Boudinot P. IFN-Stimulated Genes in Zebrafish and Humans Define an Ancient Arsenal of Antiviral Immunity. THE JOURNAL OF IMMUNOLOGY 2019; 203:3361-3373. [DOI: 10.4049/jimmunol.1900804] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 10/08/2019] [Indexed: 12/11/2022]
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13
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Xu X, Li M, Wu C, Li D, Jiang Z, Liu C, Cheng B, Mao H, Hu C. The Fish-Specific Protein Kinase (PKZ) Initiates Innate Immune Responses via IRF3- and ISGF3-Like Mediated Pathways. Front Immunol 2019; 10:582. [PMID: 30984174 PMCID: PMC6447671 DOI: 10.3389/fimmu.2019.00582] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 03/04/2019] [Indexed: 11/13/2022] Open
Abstract
PKZ is a fish-specific protein kinase containing Zα domains. PKZ is known to induce apoptosis through phosphorylating eukaryotic initiation factor 2α kinase (eIF2α) in the same way as double-stranded RNA-dependent protein kinase (PKR), but its exact role in detecting pathogens remains to be fully elucidated. Herein, we have found that PKZ acts as a fish-specific DNA sensor by initiating IFN expression through IRF3- or ISGF3-like mediated pathways. The expression pattern of PKZ is similar to those of innate immunity mediators stimulated by poly (dA:dT) and poly (dG:dC). DNA-PKZ interaction can enhance PKZ phosphorylation and dimerization in vitro. These findings indicate that PKZ participates in cytoplasmic DNA-mediated signaling. Subcellular localization assays have also shown that PKZ is located in the cytoplasm, which suggests that PKZ acts as a cytoplasmic PRR. Meanwhile, co-IP assays have shown that PKZ can separately interact with IRF3, STING, ZDHHC1, eIF2α, IRF9, and STAT2. Further investigations have revealed that PKZ can activate IRF3 and STAT2; and that IRF3-dependent and ISGF3-like dependent mediators are critical for PKZ-induced IFN expression. These results demonstrate that PKZ acts as a special DNA pattern-recognition receptor, and that PKZ can trigger immune responses through IRF3-mediated or ISGF3-like mediated pathways in fish.
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Affiliation(s)
- Xiaowen Xu
- College of Life Science, Nanchang University, Nanchang, China
| | - Meifeng Li
- College of Life Science, Nanchang University, Nanchang, China
| | - Chuxin Wu
- College of Life Science, Nanchang University, Nanchang, China
| | - Dongming Li
- Fuzhou Medical College, Nanchang University, Fuzhou, China
| | - Zeyin Jiang
- College of Life Science, Nanchang University, Nanchang, China
| | - Changxin Liu
- College of Life Science, Nanchang University, Nanchang, China
| | - Bo Cheng
- College of Life Science, Nanchang University, Nanchang, China
| | - Huiling Mao
- College of Life Science, Nanchang University, Nanchang, China
| | - Chengyu Hu
- College of Life Science, Nanchang University, Nanchang, China
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14
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Xu C, Gamil AAA, Munang'andu HM, Evensen Ø. Apoptosis Induction by dsRNA-Dependent Protein Kinase R (PKR) in EPC Cells via Caspase 8 and 9 Pathways. Viruses 2018; 10:E526. [PMID: 30261686 PMCID: PMC6213184 DOI: 10.3390/v10100526] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/22/2018] [Accepted: 09/25/2018] [Indexed: 12/18/2022] Open
Abstract
dsRNA-dependent protein kinase R (PKR) is an interferon-inducible protein that mediates antiviral effects and induces apoptosis. We studied PKR-related apoptosis mechanisms by transfecting wild type pcDNA-carp-wtPKR, a catalytically inactive mutant pcDNA-mut-carpPKR, and empty plasmid in Epithelioma papulosum cyprini (EPC) cells, designated wtPKR, mutPKR, and pcDNA3.1, respectively. PKR was inefficiently expressed from wtPKR unlike mutPKR that produced high PKR levels detected by western blot. eIF2α phosphorylation increased in wtPKR-transfected cells, while for mutPKR, phosphorylation was not different from non-transfected controls. Flow-cytometry revealed high level of apoptosis in wtPKR transfected cells, corresponding with high cytopathic effect. mutPKR and pcDNA3.1 transfection gave significantly less apoptosis and were not different from each other. Caspase-8 and -9 were activated for wtPKR, suggesting death receptor-caspase-8 and mitochondrion-dependent caspase-9 activated pathways, similar to mammalian cells. These findings suggest that the induction of apoptosis via the caspase-8 and -9 pathways are conserved in vertebrate taxa and likely play a role in viral infections of lower vertebrates.
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Affiliation(s)
- Cheng Xu
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, PO Box 369, 0102 Oslo, Norway.
| | - Amr A A Gamil
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, PO Box 369, 0102 Oslo, Norway.
| | | | - Øystein Evensen
- Faculty of Veterinary Medicine, Norwegian University of Life Sciences, PO Box 369, 0102 Oslo, Norway.
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15
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Zang S, Zhang X, Zhang J, Li C, Wei J, Qin Q. Involvement of eIF2α of Epinephelus coioides in the fish immune response to virus infection. FISH & SHELLFISH IMMUNOLOGY 2018; 75:365-373. [PMID: 29454897 DOI: 10.1016/j.fsi.2018.02.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 02/03/2018] [Accepted: 02/14/2018] [Indexed: 06/08/2023]
Abstract
The eukaryotic initiation factor 2 alpha subunit (eIF2α) is a key translation regulator that plays an important role in different cellular pressures and stimuli, including virus infection. In the present study, an eIF2α homolog (EceIF2α) from the orange-spotted grouper (Epinephelus coioides) was cloned and its roles during fish viral infection were characterized. EceIF2α encodes a putative protein of 315 amino acid residues, and shares a high degree of similarity with eIF2αs from other species. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that EceIF2α was distributed in all examined tissues. Both of the expression levels of EceIF2α in the spleen and head kidney of E. coioides were up-regulated when challenged with polyinosine-polycytidylic acid (poly[I:C]). EceIF2α was abundantly distributed in both the cytoplasm and nucleus in grouper spleen (GS) cells. Over-expression of EceIF2α improved the expression of red-spotted grouper nervous necrosis virus (RGNNV) genes in GS cells. In addition, EceIF2α depressed the activation of NK-κB and IFN-β. Furthermore, dephosphorylation inhibitor treatment led to a significant decrease of RGNNV gene transcription. Taken together, these results suggest that EceIF2α might be involved in the fish immune response to virus challenge.
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Affiliation(s)
- Shaoqing Zang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; University of Chinese Academy of Sciences, Beijing 100049, China; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Xin Zhang
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Jingcheng Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; University of Chinese Academy of Sciences, Beijing 100049, China; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Chen Li
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Jingguang Wei
- College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China.
| | - Qiwei Qin
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; University of Chinese Academy of Sciences, Beijing 100049, China; College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266000, China; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
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16
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Robertsen B. The role of type I interferons in innate and adaptive immunity against viruses in Atlantic salmon. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 80:41-52. [PMID: 28196779 DOI: 10.1016/j.dci.2017.02.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/08/2017] [Accepted: 02/09/2017] [Indexed: 05/27/2023]
Abstract
Type I IFNs (IFN-I) are cytokines, which play a crucial role in innate and adaptive immunity against viruses of vertebrates. In essence, IFN-I are induced and secreted upon host cell recognition of viral nucleic acids and protect other cells against infection by inducing antiviral proteins. Atlantic salmon possesses an extraordinary repertoire of IFN-I genes encompassing at least six different classes (IFNa, IFNb, IFNc, IFNd, IFNe and IFNf) most of which are encoded by several genes. This review describes recent research on the functions of salmon IFNa, IFNb, IFNc and IFNd. As in mammals, expression of different salmon IFN-I in response to virus infection is dependent on their promoters, properties of the virus and the cell's expression of nucleic acid receptors and interferon regulatory factors (IRFs). While IFNa mainly display local antiviral activity, IFNb and IFNc show systemic antiviral activity. In addition, salmon appears to possess several IFN-I receptors, which show selectivity in binding different IFN-I. This complexity in IFN-I and receptors allows for a large variation in functions of the salmon IFN-I. Studies with intramuscular injection of IFN expression plasmids have recently provided surprising results, which may be of relevance for application of IFN-I in prophylaxis against virus infection. Firstly, injection of IFNc plasmid protected salmon presmolts against virus infection for at least 10 weeks. Secondly, IFN plasmids showed potent adjuvant activity when injected together with a DNA vaccine against infectious salmon anemia virus (ISAV).
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Affiliation(s)
- Børre Robertsen
- Norwegian College of Fishery Science, UiT-The Arctic University of Norway, 9037 Tromsø, Norway.
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17
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Huynh TP, Jancovich JK, Tripuraneni L, Heck MC, Langland JO, Jacobs BL. Characterization of a PKR inhibitor from the pathogenic ranavirus, Ambystoma tigrinum virus, using a heterologous vaccinia virus system. Virology 2017; 511:290-299. [PMID: 28919326 PMCID: PMC6192022 DOI: 10.1016/j.virol.2017.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 08/03/2017] [Accepted: 08/09/2017] [Indexed: 02/07/2023]
Abstract
Ambystoma tigrinum virus (ATV) (family Iridoviridae, genus Ranavirus) was isolated from diseased tiger salamanders (Ambystoma tigrinum stebbinsi) from the San Rafael Valley in southern Arizona, USA in 1996. Genomic sequencing of ATV, as well as other members of the genus, identified an open reading frame that has homology to the eukaryotic translation initiation factor, eIF2α (ATV eIF2α homologue, vIF2αH). Therefore, we asked if the ATV vIF2αH could also inhibit PKR. To test this hypothesis, the ATV vIF2αH was cloned into vaccinia virus (VACV) in place of the well-characterized VACV PKR inhibitor, E3L. Recombinant VACV expressing ATV vIF2αH partially rescued deletion of the VACV E3L gene. Rescue coincided with rapid degradation of PKR in infected cells. These data suggest that the salamander virus, ATV, contains a novel gene that may counteract host defenses, and this gene product may be involved in the presentation of disease caused by this environmentally important pathogen.
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Affiliation(s)
- Trung P Huynh
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA
| | - James K Jancovich
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA
| | - Latha Tripuraneni
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA
| | - Michael C Heck
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA
| | - Jeffrey O Langland
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA; Southwest College of Naturopathic Medicine, Tempe, AZ 85282, USA
| | - Bertram L Jacobs
- School of Life Sciences, and The Biodesign Institute, Center for Infectious Diseases and Vaccinology Arizona State University, Tempe, AZ 85287-5001, USA.
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18
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Abstract
We first review fundamental insights into anti-ranavirus immunity learned with the Xenopus laevis/ranavirus FV3 model that are generally applicable to ectothermic vertebrates. We then further investigate FV3 genes involved in immune evasion. Focusing on FV3 knockout (KO) mutants defective for a putative viral caspase activation and recruitment domain-containing (CARD)-like protein (Δ64R-FV3), a β-hydroxysteroid dehydrogenase homolog (Δ52L-FV3), and an immediate-early18kDa protein (FV3-Δ18K), we assessed the involvement of these viral genes in replication, dissemination and interaction with peritoneal macrophages in tadpole and adult frogs. Our results substantiate the role of 64R and 52L as critical immune evasion genes, promoting persistence and dissemination in the host by counteracting type III IFN in tadpoles and type I IFN in adult frogs. Comparably, the substantial accumulation of genome copy numbers and exacerbation of type I and III IFN gene expression responses but deficient release of infectious virus suggests that 18K is a viral regulatory gene.
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Affiliation(s)
- Robert Jacques
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States.
| | - Eva-Stina Edholm
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States
| | - Sanchez Jazz
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States
| | - Torres-Luquis Odalys
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States
| | - De Jesús Andino Francisco
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States
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19
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Paces J, Nic M, Novotny T, Svoboda P. Literature review of baseline information to support the risk assessment of RNAi‐based GM plants. ACTA ACUST UNITED AC 2017. [PMCID: PMC7163844 DOI: 10.2903/sp.efsa.2017.en-1246] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jan Paces
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
| | | | | | - Petr Svoboda
- Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic (IMG)
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20
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Robert J, Jancovich JK. Recombinant Ranaviruses for Studying Evolution of Host-Pathogen Interactions in Ectothermic Vertebrates. Viruses 2016; 8:E187. [PMID: 27399758 PMCID: PMC4974522 DOI: 10.3390/v8070187] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 06/16/2016] [Accepted: 06/23/2016] [Indexed: 12/14/2022] Open
Abstract
Ranaviruses (Iridoviridae) are large DNA viruses that are causing emerging infectious diseases at an alarming rate in both wild and captive cold blood vertebrate species all over the world. Although the general biology of these viruses that presents some similarities with poxvirus is characterized, many aspects of their replication cycles, host cell interactions and evolution still remain largely unclear, especially in vivo. Over several years, strategies to generate site-specific ranavirus recombinant, either expressing fluorescent reporter genes or deficient for particular viral genes, have been developed. We review here these strategies, the main ranavirus recombinants characterized and their usefulness for in vitro and in vivo studies.
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Affiliation(s)
- Jacques Robert
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA.
| | - James K Jancovich
- Department of Biological Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Rd., San Marcos, CA 92096, USA.
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21
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Gamil AAA, Xu C, Mutoloki S, Evensen Ø. PKR Activation Favors Infectious Pancreatic Necrosis Virus Replication in Infected Cells. Viruses 2016; 8:v8060173. [PMID: 27338445 PMCID: PMC4926193 DOI: 10.3390/v8060173] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 05/31/2016] [Accepted: 06/03/2016] [Indexed: 01/17/2023] Open
Abstract
The double-stranded RNA-activated protein kinase R (PKR) is a Type I interferon (IFN) stimulated gene that has important biological and immunological functions. In viral infections, in general, PKR inhibits or promotes viral replication, but PKR-IPNV interaction has not been previously studied. We investigated the involvement of PKR during infectious pancreatic necrosis virus (IPNV) infection using a custom-made rabbit antiserum and the PKR inhibitor C16. Reactivity of the antiserum to PKR in CHSE-214 cells was confirmed after IFNα treatment giving an increased protein level. IPNV infection alone did not give increased PKR levels by Western blot, while pre-treatment with PKR inhibitor before IPNV infection gave decreased eukaryotic initiation factor 2-alpha (eIF2α) phosphorylation. This suggests that PKR, despite not being upregulated, is involved in eIF2α phosphorylation during IPNV infection. PKR inhibitor pre-treatment resulted in decreased virus titers, extra- and intracellularly, concomitant with reduction of cells with compromised membranes in IPNV-permissive cell lines. These findings suggest that IPNV uses PKR activation to promote virus replication in infected cells.
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Affiliation(s)
- Amr A A Gamil
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep., 0033 Oslo, Norway.
| | - Cheng Xu
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep., 0033 Oslo, Norway.
| | - Stephen Mutoloki
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep., 0033 Oslo, Norway.
| | - Øystein Evensen
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep., 0033 Oslo, Norway.
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22
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Hu Y, Fan L, Wu C, Wang B, Sun Z, Hu C. Identification and function analysis of the three dsRBMs in the N terminal dsRBD of grass carp (Ctenopharyngodon idella) PKR. FISH & SHELLFISH IMMUNOLOGY 2016; 50:91-100. [PMID: 26806165 DOI: 10.1016/j.fsi.2016.01.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 01/10/2016] [Accepted: 01/10/2016] [Indexed: 06/05/2023]
Abstract
The protein kinase R (PKR) can inhibit protein translation and lead to apoptosis under the circumstances of virus invasion and multiple other stress conditions. PKR is a dsRNA binding protein with a dsRBD and a kinase domain (KD). dsRBD is mostly composed of two (in mammal PKR) or three (in some fish PKR) dsRNA binding motifs (dsRBMs). Multiple sequences alignment and Phylogenetic analysis indicate that the three dsRBMs of fish PKR share analogous structure but show to be divergence origination. In this study, we have identified and analyzed the three dsRBMs from grass carp (Ctenopharyngodon idellus) PKR (CiPKR), which was cloned previously in our laboratory. dsRBMs of CiPKR have two or three conserved regions involved in dsRNA binding. Among the three dsRBMs, dsRBM1 was peculiar to some fish PKRs, while dsRBM2 and dsRBM3 were closely related to the dsRBM1 and dsRBM2 of mammal PKRs respectively. Dimerization assay indicated that dsRBM1 and dsRBM2 formed not only homo-dimer but also homo-multimer; whereas dsRBM3 formed merely homo-dimer. Meanwhile, dsRBM1-2, dsRBM2-3 and dsRBM1-2-3 could homo-dimerize and homo-multimerize also. Poly I:C pull-down assay showed that the binding of dsRBM to Poly I:C needed two or three dsRBMs to cooperate in vitro, meaning one dsRBM from CiPKR could not bind to dsRNA efficiently. To further investigate the effect of dsRBM on the function of CiPKR, we constructed pcDNA3.1/CiPKR-wt and a series of CiPKR mutants recombined plasmids including pcDNA3.1/CiPKR-ΔdsRBM2-3, pcDNA3.1/CiPKR-ΔdsRBM1,3, pcDNA3.1/CiPKR-ΔdsRBM1-2, pcDNA3.1/CiPKR-ΔdsRBM3, pcDNA3.1/CiPKR-ΔdsRBM1. The recombined plasmids respectively were co-transfected with plasmid PGL3 promoter into CIK cells. In comparison with the control group, the luciferase translation inhibitions were 78.7%, 15%, 0, 0.5%, 61.8%, 67.3% respectively. The results indicated that the protein translation inhibition caused by CiPKR mutants with only one dsRBM were very weak, while those with two or three dsRBMs inhibited the protein translation powerfully. Cell viability were 34.2%, 98.2%, 112%, 108%, 50.3%, 47.5% respectively after transfected with pcDNA3.1/CiPKR-wt, pcDNA3.1/CiPKR-ΔdsRBM2-3, pcDNA3.1/CiPKR-ΔdsRBM1,3, pcDNA3.1/CiPKR-ΔdsRBM1-2, pcDNA3.1/CiPKR-ΔdsRBM3, pcDNA3.1/CiPKR-ΔdsRBM1 in order into CIK cells for 48 h. The results from cell counting also indicated that transfection of CiPKR-wt and the mutants CiPKR-ΔdsRBM3, CiPKR-ΔdsRBM1 could inhibit the protein translation and facilitated the decrease of CIK cells number. In conclusion, our observations suggested that two dsRBMs ranking in tandem at N terminal were essential for the function of CiPKR, and the presence of the extra dsRBM1 enhanced its function.
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Affiliation(s)
- Yousheng Hu
- Department of Bioscience, College of Life Science, Nanchang University, Nanchang, 330031, China; Medical College, Jinggangshan University, Ji'an, 343009, China
| | - Lihua Fan
- Department of Bioscience, College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Chuxin Wu
- Nanchang Teachers College, Nanchang, 330103, China
| | - Binhua Wang
- Department of Bioscience, College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Zhicheng Sun
- Department of Bioscience, College of Life Science, Nanchang University, Nanchang, 330031, China
| | - Chengyu Hu
- Department of Bioscience, College of Life Science, Nanchang University, Nanchang, 330031, China.
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Liu D, Mao H, Gu M, Xu X, Sun Z, Lin G, Wang H, Xie D, Hou Q, Wang X, Mi Y, Liu X, Hu C. The transcription regulation analysis of Ctenopharyngodon idellus PKR and PKZ genes. Gene 2016; 576:512-9. [DOI: 10.1016/j.gene.2015.10.070] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 10/06/2015] [Accepted: 10/30/2015] [Indexed: 01/20/2023]
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24
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Wu C, Hu Y, Fan L, Wang H, Sun Z, Deng S, Liu Y, Hu C. Ctenopharyngodon idella PKZ facilitates cell apoptosis through phosphorylating eIF2α. Mol Immunol 2016; 69:13-23. [DOI: 10.1016/j.molimm.2015.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 11/08/2015] [Accepted: 11/11/2015] [Indexed: 11/24/2022]
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25
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Wulff JA, White JA. The Endosymbiont Arsenophonus Provides a General Benefit to Soybean Aphid (Hemiptera: Aphididae) Regardless of Host Plant Resistance (Rag). ENVIRONMENTAL ENTOMOLOGY 2015; 44:574-81. [PMID: 26313962 DOI: 10.1093/ee/nvv031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 02/18/2015] [Indexed: 06/04/2023]
Abstract
Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), invokes substantial chemical treatment and economic cost in North America. Resistant soybean genotypes hold promise as a low-impact control methodology, but soybean aphid "biotypes" capable of development on resistant soy cast doubt on the durability of soy resistance. We hypothesized that variation in soybean aphid ability to colonize resistant soy is partially attributable to a bacterial symbiont of soybean aphid, Arsenophonus. We used microinjection to manipulate Arsenophonus infection in both virulent and avirulent aphid biotypes, resulting in five pairs of infected versus uninfected isolines. These isolines were subjected to various population growth rate assays on resistant Rag versus susceptible soybean. We found that aphid virulence on Rag soybean was not dependent on Arsenophonus: virulent aphid biotypes performed well on Rag soybean, and avirulent aphid biotypes performed poorly on Rag soybean, regardless of whether Arsenophonus was present or not. However, we did find that Arsenophonus-infected clones on average performed significantly better than their paired uninfected isolines. This pattern was not consistently evident on every date for every clone, either in the population assays nor when we compared lifetime fecundity of individual aphids in a separate experiment. Nevertheless, this overall benefit for infected aphids may be sufficient to explain the high frequency of Arsenophonus infection in soybean aphids.
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Affiliation(s)
- Jason A Wulff
- Department of Entomology, University of Kentucky, Lexington, KY 40546, USA.
| | - Jennifer A White
- Department of Entomology, University of Kentucky, Lexington, KY 40546, USA
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Insights into the antiviral immunity against grass carp (Ctenopharyngodon idella) reovirus (GCRV) in grass carp. J Immunol Res 2015; 2015:670437. [PMID: 25759845 PMCID: PMC4337036 DOI: 10.1155/2015/670437] [Citation(s) in RCA: 134] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 12/12/2014] [Indexed: 12/13/2022] Open
Abstract
Global fish production from aquaculture has rapidly grown over the past decades, and grass carp shares the largest portion. However, hemorrhagic disease caused by grass carp reovirus (GCRV) results in tremendous loss of grass carp (Ctenopharyngodon idella) industry. During the past years, development of molecular biology and cellular biology technologies has promoted significant advances in the understanding of the pathogen and the immune system. Immunoprophylaxis based on stimulation of the immune system of fish has also got some achievements. In this review, authors summarize the recent progresses in basic researches on GCRV; viral nucleic acid sensors, high-mobility group box proteins (HMGBs); pattern recognition receptors (PRRs), Toll-like receptors (TLRs) and retinoic acid inducible gene I- (RIG-I-) like receptors (RLRs); antiviral immune responses induced by PRRs-mediated signaling cascades of type I interferon (IFN-I) and IFN-stimulated genes (ISGs) activation. The present review also notices the potential applications of molecule genetic markers. Additionally, authors discuss the current preventive and therapeutic strategies (vaccines, RNAi, and prevention medicine) and highlight the importance of innate immunity in long term control for grass carp hemorrhagic disease.
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da Silva Augusto L, Moretti NS, Ramos TCP, de Jesus TCL, Zhang M, Castilho BA, Schenkman S. A membrane-bound eIF2 alpha kinase located in endosomes is regulated by heme and controls differentiation and ROS levels in Trypanosoma cruzi. PLoS Pathog 2015; 11:e1004618. [PMID: 25658109 PMCID: PMC4450062 DOI: 10.1371/journal.ppat.1004618] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 12/10/2014] [Indexed: 12/29/2022] Open
Abstract
Translation initiation has been described as a key step for the control of growth and differentiation of several protozoan parasites in response to environmental changes. This occurs by the activation of protein kinases that phosphorylate the alpha subunit of the translation initiation factor 2 (eIF2α), which decreases translation, and in higher eukaryotes favors the expression of stress remedial response genes. However, very little is known about the signals that activate eIF2α kinases in protozoan parasites. Here, we characterized an eIF2α kinase of Trypanosoma cruzi (TcK2), the agent of Chagas’ disease, as a transmembrane protein located in organelles that accumulate nutrients in proliferating parasite forms. We found that heme binds specifically to the catalytic domain of the kinase, inhibiting its activity. In the absence of heme, TcK2 is activated, arresting cell growth and inducing differentiation of proliferative into infective and non-proliferative forms. Parasites lacking TcK2 lose this differentiation capacity and heme is not stored in reserve organelles, remaining in the cytosol. TcK2 null cells display growth deficiencies, accumulating hydrogen peroxide that drives the generation of reactive oxygen species. The augmented level of hydrogen peroxide occurs as a consequence of increased superoxide dismutase activity and decreased peroxide activity. These phenotypes could be reverted by the re-expression of the wild type but not of a TcK2 dead mutant. These findings indicate that heme is a key factor for the growth control and differentiation through regulation of an unusual type of eIF2α kinase in T. cruzi. Trypanosoma cruzi proliferates as epimastigotes in the midgut of the insect vector filled with blood meal. There, it accumulates nutrients in specific endosomal organelles. The parasite moves towards the hindgut and when the blood is completely digested, these organelles are consumed. At this moment, the insect is ready for a new feeding cycle that promotes the release of infective metacyclic-trypomastigote forms. We have previously found that such differentiation involves protein synthesis arrest through the phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α). Now, we show that one of the kinases (TCK2) that phosphorylate eIF2α is localized in these endosomes. TcK2 binds and is specifically inhibited by heme derived from blood hemoglobin. We also found that heme inhibits differentiation, suggesting that it is an important signal for differentiation. By generating knockouts of TcK2, we observed an increased accumulation of heme in the cytosol, which induced cellular damage by affecting the reactive oxygen metabolism in the parasite. We conclude that this eIF2α kinase senses cytosolic heme obtained from the blood meal, promoting its storage in the cytosolic organelles. When heme levels are decreased in the cytosol, TcK2 activation can then arrest protein synthesis that is followed by the induction of the differentiation of proliferative epimastigote forms to infective metacyclic-trypomastigotes.
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Affiliation(s)
- Leonardo da Silva Augusto
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Nilmar Silvio Moretti
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Thiago Cesar Prata Ramos
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Teresa Cristina Leandro de Jesus
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Min Zhang
- Department of Pathology, New York University School of Medicine, New York, New York, United States of America
| | - Beatriz A. Castilho
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
| | - Sergio Schenkman
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, São Paulo, Brazil
- * E-mail:
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Cofre C, Gonzalez R, Moya J, Vidal R. Phenotype gene expression differences between resistant and susceptible salmon families to IPNV. FISH PHYSIOLOGY AND BIOCHEMISTRY 2014; 40:887-96. [PMID: 24306554 DOI: 10.1007/s10695-013-9894-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 11/22/2013] [Indexed: 05/22/2023]
Abstract
Infectious pancreatic necrosis virus (IPNV) is an economically important pathogen of the salmonid aquaculture industry. Selective breeding has been employed to improve resistance to this infectious disease, and it is of importance to investigate the expression profile of immune genes of Atlantic salmon with different genetic background in response to this virus. This study examined the immune modulation response of eight candidate genes in head kidney tissue in two families of Atlantic salmon with high and low mortalities, after challenge with IPNV. The results showed that the expression pattern of target genes differed in the two families. Generally, higher expression of antiviral, pro-inflammatory genes and transcription factors such as tripartite motif, NF-κB, IFNI, STAT1, protein kinase R, and Vig-2 in the resistant family were observed at the same time point. One may speculate the functional importance of these putative candidate genes in the characterization of the IPNV-resistant (low mortalities) immune phenotype. Therefore, on our findings, we suggest that future salmonids studies aiming to identify candidate genes/pathway or vaccines evaluation should consider validating detected genes/pathway across different genetic backgrounds or immune phenotype.
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Affiliation(s)
- C Cofre
- Laboratory of Molecular Ecology, Genomics and Evolutionary Studies, Department of Biology, Faculty of Chemistry and Biology, Universidad Santiago de Chile, Av. Libertador Bernardo O'Higgins 3363, Estación Central, Santiago, Chile
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Kim D, Hur J, Park K, Bae S, Shin D, Ha SC, Hwang HY, Hohng S, Lee JH, Lee S, Kim YG, Kim KK. Distinct Z-DNA binding mode of a PKR-like protein kinase containing a Z-DNA binding domain (PKZ). Nucleic Acids Res 2014; 42:5937-48. [PMID: 24682817 PMCID: PMC4027156 DOI: 10.1093/nar/gku189] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Double-stranded ribonucleic acid-activated protein kinase (PKR) downregulates translation as a defense mechanism against viral infection. In fish species, PKZ, a PKR-like protein kinase containing left-handed deoxyribonucleic acid (Z-DNA) binding domains, performs a similar role in the antiviral response. To understand the role of PKZ in Z-DNA recognition and innate immune response, we performed structural and functional studies of the Z-DNA binding domain (Zα) of PKZ from Carassius auratus (caZαPKZ). The 1.7-Å resolution crystal structure of caZαPKZ:Z-DNA revealed that caZαPKZ shares the overall fold with other Zα, but has discrete structural features that differentiate its DNA binding mode from others. Functional analyses of caZαPKZ and its mutants revealed that caZαPKZ mediates the fastest B-to-Z transition of DNA among Zα, and the minimal interaction for Z-DNA recognition is mediated by three backbone phosphates and six residues of caZαPKZ. Structure-based mutagenesis and B-to-Z transition assays confirmed that Lys56 located in the β-wing contributes to its fast B-to-Z transition kinetics. Investigation of the DNA binding kinetics of caZαPKZ further revealed that the B-to-Z transition rate is positively correlated with the association rate constant. Taking these results together, we conclude that the positive charge in the β-wing largely affects fast B-to-Z transition activity by enhancing the DNA binding rate.
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Affiliation(s)
- Doyoun Kim
- Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea
| | - Jeonghwan Hur
- Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea
| | - Kwangsoo Park
- Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea
| | - Sangsu Bae
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea National Center for Creative Research Initiatives, Seoul National University, Seoul 151-747, Korea
| | - Donghyuk Shin
- Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Korea
| | - Sung Chul Ha
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Kyungbuk 790-784, Korea
| | - Hye-Yeon Hwang
- Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea
| | - Sungchul Hohng
- Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea National Center for Creative Research Initiatives, Seoul National University, Seoul 151-747, Korea Department of Biophysics and Chemical Biology, Seoul National University, Seoul 151-747, Korea
| | - Joon-Hwa Lee
- Department of Chemistry and RINS, Gyeongsang National University, Jinju, Gyeongnam 660-701, Korea
| | - Sangho Lee
- Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Korea
| | - Yang-Gyun Kim
- Department of Chemistry, Sungkyunkwan University, Suwon 440-746, Korea
| | - Kyeong Kyu Kim
- Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Korea
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Gig1, a novel antiviral effector involved in fish interferon response. Virology 2014; 448:322-32. [DOI: 10.1016/j.virol.2013.10.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/27/2013] [Accepted: 10/21/2013] [Indexed: 11/23/2022]
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Lu P, Deng S, Wu C, Zhu Y, Liu Y, Lin G, Yan Y, Hu C. The Zα domain of fish PKZ converts DNA hairpin with d(GC)(n) inserts to Z-conformation. Acta Biochim Biophys Sin (Shanghai) 2013; 45:1062-8. [PMID: 24113090 DOI: 10.1093/abbs/gmt114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
PKZ, protein kinase containing Z-DNA domains, is a novel member of the vertebrate eIF2α kinase family. Containing a catalytic domain in C-terminus and two Z-DNA binding domains (Zα1 and Zα2) in N-terminus, PKZ can be activated through the binding of Zα to Z-DNA. However, the regulatory function of PKZ Zα remains to be established. Here, to understand the impact of PKZ Zα on DNA conformational transition, wild-type Zα1Zα2 and 11 mutant proteins were expressed and purified. At the same time, several different lengths of DNA hairpins-d(GC)nT4(GC)n (n = 2-6) and an RNA hairpin-r(GC)6T4(GC)6 were synthesized. The effects of Zα1Zα2 and mutant proteins on the conformation of these synthetic DNA or RNA hairpins were investigated by using circular dichroism spectrum and gel mobility shift assays. The results showed that DNA hairpins retained a conventional B-DNA conformation in the absence of Zα1Zα2, while some of the DNA hairpins (n≥3) were converted to Z-conformation under Zα1Zα2 induction. The tendency was proportionally associated with the increasing amount of GC repeat. In comparison with Zα1Zα2, Zα1Zα1 rather than Zα2Zα2 displayed a higher ability in converting d(GC)6T4(GC)6 from B- to Z-DNA. These results demonstrated that Zα1 sub-domain played a more essential role in the process of B-Z conformational transition than Zα2 sub-domain did. Mutant proteins (K34A, N38A, R39A, Y42A, P57A, P58A, and W60A) could not convert d(GC)6T4(GC)6 into Z-DNA, whereas S35A or K56A retained some partial activities. Interestingly, Zα1Zα2 was also able to induce r(GC)6T4(GC)6 RNA from A-conformation to Z-conformation under appropriate conditions.
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MESH Headings
- Animals
- Base Sequence
- Circular Dichroism
- DNA, A-Form/chemistry
- DNA, A-Form/genetics
- DNA, A-Form/metabolism
- DNA, B-Form/chemistry
- DNA, B-Form/genetics
- DNA, B-Form/metabolism
- DNA, Z-Form/chemistry
- DNA, Z-Form/genetics
- DNA, Z-Form/metabolism
- Fish Proteins/chemistry
- Fish Proteins/genetics
- Fish Proteins/metabolism
- Goldfish
- Mutation
- Nucleic Acid Conformation
- Oligodeoxyribonucleotides/chemistry
- Oligodeoxyribonucleotides/metabolism
- Oligoribonucleotides/chemistry
- Oligoribonucleotides/metabolism
- Protein Binding
- Protein Structure, Tertiary
- eIF-2 Kinase/chemistry
- eIF-2 Kinase/genetics
- eIF-2 Kinase/metabolism
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Affiliation(s)
- Puzhong Lu
- Department of Bioscience, College of Life Science and Food Engineering, Nanchang University, Nanchang 330031, China
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Hu YS, Li W, Li DM, Liu Y, Fan LH, Rao ZC, Lin G, Hu CY. Cloning, expression and functional analysis of PKR from grass carp (Ctenopharyngodon idellus). FISH & SHELLFISH IMMUNOLOGY 2013; 35:1874-1881. [PMID: 24084043 DOI: 10.1016/j.fsi.2013.09.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 09/12/2013] [Accepted: 09/16/2013] [Indexed: 06/02/2023]
Abstract
The interferon-induced, dsRNA-activated protein kinase (PKR) is considered as an important component of innate immune system and as a representative effector protein of interferon system. In the present study, PKR gene (CiPKR, JX511974) from grass carp (Ctenopharyngodon idellus) was isolated and identified using homology-based PCR. CiPKR shares high sequence identity with the counterparts of goldfish (Crucian carp) and zebrafish (Danio rerio). The full-length cDNA of CiPKR was found to be 2436 bp, with an ORF of 2067 bp that encodes a polypeptide of 688 amino acids. The deduced polypeptide CiPKR contains three tandem dsRNA-binding motifs (dsRBMs) at the N-terminus and a conserved Ser/Thr kinase domain at the C-terminus. CiPKR was expressed ubiquitously at a low-level under normal conditions, but it could be up-regulated after intraperitoneal (ip) injection with grass carp haemorrhagic virus (GCHV). CiPKR was dramatically up-regulated at 6 h post-injection and then recovered rapidly to normal levels within 24 h; however, it was obviously up-regulated once again at 48 h or 72 h post-injection. It seemed that CiPKR could respond to GCHV infection in an IFN-independent as well as an IFN-dependent pathway. To further investigate its mechanism of biological actions, we constructed a series of recombinant plasmids including pcDNA3.1/PKR-wt, pcDNA3.1/PKR-K430R, pcDNA3.1/PKR-C (deletion of dsRBD sequence) and pcDNA3.1/PKR-C-K430R, and then each recombinant plasmid was transfected into CIK cells. In comparison with those of controls, a 79% and a 64% decrease of luciferase activities were detected in the tested cells transfected with CiPKR and CiPKR-C, respectively; however, luciferase activities were increased in those cells transfected with PKR-K430R and PKR-C-K430R, with a 160% and 115% up-regulation, respectively. Similarly, MTT colorimetric assay indicated that cell viabilities of CIK cells transfected with pcDNA3.1/PKR-wt, pcDNA3.1/PKR-K430R, pcDNA3.1/PKR-C and pcDNA3.1/PKR-C-K430R were 49%, 90%, 54% and 100%, respectively. Our observations suggested that the expression of CiPKR could be up-regulated following viral infection, and then resulted in the inhibition of protein synthesis and the induction of potential apoptosis.
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Affiliation(s)
- You-Sheng Hu
- Department of Bioscience, College of Life Science and Food Engineering, Nanchang University, Nanchang 330031, China; Medical College, Jinggangshan University, Ji'an 343009, China
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de Rosa M, Zacarias S, Athanasiadis A. Structural basis for Z-DNA binding and stabilization by the zebrafish Z-DNA dependent protein kinase PKZ. Nucleic Acids Res 2013; 41:9924-33. [PMID: 23975196 PMCID: PMC3834819 DOI: 10.1093/nar/gkt743] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The RNA-dependent protein kinase PKR plays a central role in the antiviral defense of vertebrates by shutting down protein translation upon detection of viral dsRNA in the cytoplasm. In some teleost fish, PKZ, a homolog of PKR, performs the same function, but surprisingly, instead of dsRNA binding domains, it harbors two Z-DNA/Z-RNA-binding domains belonging to the Zalpha domain family. Zalpha domains have also been found in other proteins, which have key roles in the regulation of interferon responses such as ADAR1 and DNA-dependent activator of IFN-regulatory factors (DAI) and in viral proteins involved in immune response evasion such as the poxviral E3L and the Cyprinid Herpesvirus 3 ORF112. The underlying mechanism of nucleic acids binding and stabilization by Zalpha domains is still unclear. Here, we present two crystal structures of the zebrafish PKZ Zalpha domain (DrZalphaPKZ) in alternatively organized complexes with a (CG)6 DNA oligonucleotide at 2 and 1.8 Å resolution. These structures reveal novel aspects of the Zalpha interaction with DNA, and they give insights on the arrangement of multiple Zalpha domains on DNA helices longer than the minimal binding site.
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Affiliation(s)
| | | | - Alekos Athanasiadis
- *To whom correspondence should be addressed. Tel: +351 21 4464648; Fax: +351 21 4407970;
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Taghavi N, Samuel CE. RNA-dependent protein kinase PKR and the Z-DNA binding orthologue PKZ differ in their capacity to mediate initiation factor eIF2α-dependent inhibition of protein synthesis and virus-induced stress granule formation. Virology 2013; 443:48-58. [PMID: 23706307 DOI: 10.1016/j.virol.2013.04.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/03/2013] [Accepted: 04/22/2013] [Indexed: 02/07/2023]
Abstract
Protein kinase R (PKR), a regulator of translation in mammalian cells, possesses two ds-RNA binding domains responsible for kinase activation. Protein kinase Z (PKZ), a PKR-like kinase present in fish, possesses two Z-DNA binding domains. A complementation strategy with cells stably deficient in PKR was used to compare the functions of PKR and PKZ. We found reporter expression was inhibited by wildtype (WT) PKR but not by either catalytic (K296R) or RNA-binding (K64E) mutants. PKZ, like PKR, more potently inhibited 5' cap-dependent compared to IRES-dependent reporter expression. However, in contrast to PKR-expressing cells, phosphorylation of initiation factor eIF2α was not detectably increased in PKZ-expressing cells. Furthermore, virus-induced stress granule formation was observed in PKR-deficient cells complemented with WT PKR but not K296R mutant PKR or WT PKZ. These results suggest that PKR and PKZ function by distinguishable mechanisms to modulate host responses including protein synthesis inhibition and stress granule formation.
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Affiliation(s)
- Nora Taghavi
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California 93106, USA
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35
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Lu P, Deng S, Zhu Y, Yan Y, Liu Y, Hu C. The Zα domain of fish PKZ facilitates the B-Z conformational transition of oligonucleotide DNAs with d(GC)(n) inserts. Acta Biochim Biophys Sin (Shanghai) 2012; 44:957-63. [PMID: 23034482 DOI: 10.1093/abbs/gms081] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PKZ (PKR-like) was discovered as a member of elF2α kinase family in fish, which possesses a conserved catalytic domain of an eIF2α kinase in C-terminal and also two Z-DNA-binding domains (Zα1 and Zα2) in N-terminal. PKZ can be activated through binding of Zα to Z-DNA. However, the regulatory function of PKZ Zα still remains unclear. To investigate a molecular mechanism of how PKZ Zα interacts with Z-DNA, we expressed Zα polypeptide Zα1α2 in Escherichia coli Rosetta strain and purified by affinity chromatography on Ni-NTA resin. Different lengths of oligonucleotide DNAs with various inserts, namely d(GC)(n) (n = 6, 8, 10, 13), d(TA)(n) (n = 6, 10), non-d(GC), and non-d(TA), were designed and synthesized. Circular dichroism spectrum and gel mobility shift assays were used to investigate the effects of Zα1α2 on the conformational transition of different oligonucleotide DNAs. Results showed that oligonucleotide DNAs retained a conventional B-DNA conformation in the absence of Zα1α2. With the increasing amount of Zα1α2 titration, d(GC)(n) were recognized and converted to Z-DNA conformation to some degree. With increasing the repeat number (from n = 6 to n = 13), the tendency of conformational transition became more obvious. However, the conformation of oligonucleotides with d(TA)(n) inserts changed a little in the presence of Zα1α2, and Zα1α2 had no effect on conformational transition of oligonucleotides with non-d(GC) or non-d(TA) inserts. Gel mobility shift assays further showed that Zα1α2 could bind to oligonucleotide with d(GC)(10). In other words, Zα1α2 can turn oligonucleotides with d(GC)(n) inserts into Z-DNA conformation and bind to it with high affinity.
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Affiliation(s)
- Puzhong Lu
- Department of Bioscience, College of Life Science and Food Engineering, Nanchang University, Nanchang 330031, China
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36
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Zhang YB, Gui JF. Molecular regulation of interferon antiviral response in fish. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2012; 38:193-202. [PMID: 22721905 DOI: 10.1016/j.dci.2012.06.003] [Citation(s) in RCA: 206] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 06/08/2012] [Accepted: 06/08/2012] [Indexed: 05/07/2023]
Abstract
Interferon (IFN) response is the first line of host defense against virus infection. The recent years have witnessed tremendous progress in understanding of fish IFN antiviral response. Varied number of IFN genes has been identified in different fish species but obviously, they do not show a one-to-one orthologous relationship with mammalian IFN homologs. These genes are divided into two groups with different abilities to induce downstream gene expression through binding to different receptor complexes. Consistently, some fish IFN-stimulated genes such as Mx and PKR have been confirmed for their antiviral effects. In this review, we focus on how fish cells respond to IFNs and how fish IFNs are triggered through TLR pathway and RLR pathway. We highlight the roles of IRF3 and IRF7 in activation of fish IFN response. In addition, the unique mechanisms underlying IRF3/7-dependent fish IFN response and auto-regulation of fish IFN gene expression are discussed.
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Affiliation(s)
- Yi-Bing Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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Immanuel TM, Greenwood DR, MacDiarmid RM. A critical review of translation initiation factor eIF2α kinases in plants - regulating protein synthesis during stress. FUNCTIONAL PLANT BIOLOGY : FPB 2012; 39:717-735. [PMID: 32480823 DOI: 10.1071/fp12116] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 07/10/2012] [Indexed: 05/10/2023]
Abstract
Eukaryotic cells must cope with environmental stress. One type of general stress response is the downregulation of protein synthesis in order to conserve cellular resources. Protein synthesis is mainly regulated at the level of mRNA translation initiation and when the α subunit of eukaryotic translation initiation factor 2 (eIF2) is phosphorylated, protein synthesis is downregulated. Although eIF2 has the same translation initiation function in all eukaryotes, it is not known whether plants downregulate protein synthesis via eIF2α phosphorylation. Similarly, although there is evidence that plants possess eIF2α kinases, it is not known whether they operate in a similar manner to the well characterised mammalian and yeast eIF2α kinases. Two types of eIF2α kinases have been reported in plants, yet the full understanding of the plant eIF2α phosphorylation mechanism is still lacking. Here we review the current knowledge of the eIF2α phosphorylation mechanism within plants and discuss plant eIF2α, plant eIF2α kinase GCN2 and the data supporting and contradicting the hypothesis that a functional orthologue for the eIF2α kinase PKR, is present and functional in plants.
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Affiliation(s)
- Tracey M Immanuel
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 92169, Auckland, 1142, New Zealand
| | - David R Greenwood
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 92169, Auckland, 1142, New Zealand
| | - Robin M MacDiarmid
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 92169, Auckland, 1142, New Zealand
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Hernández G, Proud CG, Preiss T, Parsyan A. On the Diversification of the Translation Apparatus across Eukaryotes. Comp Funct Genomics 2012; 2012:256848. [PMID: 22666084 PMCID: PMC3359775 DOI: 10.1155/2012/256848] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Accepted: 03/07/2012] [Indexed: 11/21/2022] Open
Abstract
Diversity is one of the most remarkable features of living organisms. Current assessments of eukaryote biodiversity reaches 1.5 million species, but the true figure could be several times that number. Diversity is ingrained in all stages and echelons of life, namely, the occupancy of ecological niches, behavioral patterns, body plans and organismal complexity, as well as metabolic needs and genetics. In this review, we will discuss that diversity also exists in a key biochemical process, translation, across eukaryotes. Translation is a fundamental process for all forms of life, and the basic components and mechanisms of translation in eukaryotes have been largely established upon the study of traditional, so-called model organisms. By using modern genome-wide, high-throughput technologies, recent studies of many nonmodel eukaryotes have unveiled a surprising diversity in the configuration of the translation apparatus across eukaryotes, showing that this apparatus is far from being evolutionarily static. For some of the components of this machinery, functional differences between different species have also been found. The recent research reviewed in this article highlights the molecular and functional diversification the translational machinery has undergone during eukaryotic evolution. A better understanding of all aspects of organismal diversity is key to a more profound knowledge of life.
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Affiliation(s)
- Greco Hernández
- Division of Basic Research, National Institute for Cancer (INCan), Avenida San Fernando No. 22, Col. Sección XVI, Tlalpan, 14080 Mexico City, Mexico
| | - Christopher G. Proud
- Centre for Biological Sciences, University of Southampton, Life Sciences Building (B85), Southampton SO17 1BJ, UK
| | - Thomas Preiss
- Genome Biology Department, The John Curtin School of Medical Research, The Australian National University, Building 131, Garran Road, Acton, Canberra, ACT 0200, Australia
| | - Armen Parsyan
- Goodman Cancer Centre and Department of Biochemistry, Faculty of Medicine, McGill University, 1160 Pine Avenue West, Montreal, QC, Canada H3A 1A3
- Division of General Surgery, Department of Surgery, Faculty of Medicine, McGill University Health Centre, Royal Victoria Hospital, 687 Pine Avenue West, Montreal, QC, Canada H3A 1A1
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The dominant-negative inhibition of double-stranded RNA-dependent protein kinase PKR increases the efficacy of Rift Valley fever virus MP-12 vaccine. J Virol 2012; 86:7650-61. [PMID: 22573861 DOI: 10.1128/jvi.00778-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rift Valley fever virus (RVFV), belonging to the genus Phlebovirus, family Bunyaviridae, is endemic to sub-Saharan Africa and causes a high rate of abortion in ruminants and hemorrhagic fever, encephalitis, or blindness in humans. MP-12 is the only RVFV strain excluded from the select-agent rule and handled at a biosafety level 2 (BSL2) laboratory. MP-12 encodes a functional major virulence factor, the NSs protein, which contributes to its residual virulence in pregnant ewes. We found that 100% of mice subcutaneously vaccinated with recombinant MP-12 (rMP12)-murine PKRN167 (mPKRN167), which encodes a dominant-negative form of mouse double-stranded RNA (dsRNA)-dependent protein kinase (PKR) in place of NSs, were protected from wild-type (wt) RVFV challenge, while 72% of mice vaccinated with MP-12 were protected after challenge. rMP12-mPKRN167 induced alpha interferon (IFN-α) in sera, accumulated RVFV antigens in dendritic cells at the local draining lymph nodes, and developed high levels of neutralizing antibodies, while parental MP-12 induced neither IFN-α nor viral-antigen accumulation at the draining lymph node yet induced a high level of neutralizing antibodies. The present study suggests that the expression of a dominant-negative PKR increases the immunogenicity and efficacy of live-attenuated RVFV vaccine, which will lead to rational design of safe and highly immunogenic RVFV vaccines for livestock and humans.
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Taghavi N, Samuel CE. Protein kinase PKR catalytic activity is required for the PKR-dependent activation of mitogen-activated protein kinases and amplification of interferon beta induction following virus infection. Virology 2012; 427:208-16. [PMID: 22381929 DOI: 10.1016/j.virol.2012.01.029] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 12/08/2011] [Accepted: 01/25/2012] [Indexed: 12/24/2022]
Abstract
The protein kinase regulated by RNA (PKR) enhances both activation of mitogen-activated protein kinases and the induction of interferon beta (IFN-β) by measles virus defective in C-protein expression (C(ko)). Here we used complementation of human cell lines stably deficient in PKR (PKR(kd)) to probe the basis of these PKR-mediated responses. We found that PKR(kd) HeLa and amnion U cell lines were defective for virus-mediated activation of IFN induction signaling components compared to PKR-sufficient control cells. Complementation of PKR(kd) cells with wildtype PKR, but not with PKR mutants defective in either catalytic activity or dsRNA-binding activity, restored JNK, p38 and ATF-2 phosphorylation and enhanced IFN-β induction following infection. By contrast to mammalian PKR, the Z-DNA binding domain-containing fish homologue of PKR, PKZ, lacked the capacity to enhance C(ko) virus-mediated IFN-β induction. Furthermore, inhibition of virus growth was observed with C(ko)-infected PKR(kd) cells complemented with PKR but not with PKZ.
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Affiliation(s)
- Nora Taghavi
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
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del Castillo CS, Hikima JI, Ohtani M, Jung TS, Aoki T. Characterization and functional analysis of two PKR genes in fugu (Takifugu rubripes). FISH & SHELLFISH IMMUNOLOGY 2012; 32:79-88. [PMID: 22056498 DOI: 10.1016/j.fsi.2011.10.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 10/11/2011] [Accepted: 10/23/2011] [Indexed: 05/31/2023]
Abstract
PKR (protein kinase R) is a serine-threonine kinase that inhibits protein synthesis by the phosphorylation of the eukaryotic translation initiation factor 2-alpha (eIF2α), and activates NFκB by inducing NFκB-inducing kinase and IκB (inhibitor of NFκB) kinase. This can lead to antiviral and anti-proliferative effects. In this study, the complete sequence and organization of two fugu PKR genes (fPKRs) were determined by in silico analysis and conventional PCR. The full-length fPKR1 and fPKR2 genes were 3832 bp and 4325 bp, which encoded 523 and 492 amino acids, respectively. Both encoded two dsRNA binding domains and a Serine/Threonine protein kinase domain, and showed very high similarity to green spotted puffer PKRs. Gene expression of the two fPKRs was measured by quantitative real-time PCR on tissue samples from healthy fish and peripheral blood leukocytes stimulated with polyinosinic:polycytidylic acid (PolyI:C) or lipopolysaccharides (LPS). The fPKRs were highly expressed in the skin and fPKR2 was significantly induced in PBLs by PolyI:C but not by LPS. The fPKRs inhibited translation of a luciferase reporter gene in a dose-dependent manner and induced transcriptional activity of a mammalian NFκB luciferase reporter. These results demonstrate that two PKRs in a single species can both be independently, but not equally, functional and support the hypothesis that fish PKRs have roles in the innate immune response similar to those of mammalian PKRs.
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Affiliation(s)
- Carmelo S del Castillo
- Aquatic Biotechnology Center, College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, South Korea
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Verrier ER, Langevin C, Benmansour A, Boudinot P. Early antiviral response and virus-induced genes in fish. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2011; 35:1204-1214. [PMID: 21414349 DOI: 10.1016/j.dci.2011.03.012] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 12/21/2010] [Accepted: 03/06/2011] [Indexed: 05/30/2023]
Abstract
In fish as in mammals, virus infections induce changes in the expression of many host genes. Studies conducted during the last fifteen years revealed a major contribution of the interferon system in fish antiviral response. This review describes the screening methods applied to compare the impact of virus infections on the transcriptome in different fish species. These approaches identified a "core" set of genes that are strongly induced in most viral infections. The "core" interferon-induced genes (ISGs) are generally conserved in vertebrates, some of them inhibiting a wide range of viruses in mammals. A selection of ISGs -PKR, vig-1/viperin, Mx, ISG15 and finTRIMs - is further analyzed here to illustrate the diversity and complexity of the mechanisms involved in establishing an antiviral state. Most of the ISG-based pathways remain to be directly determined in fish. Fish ISGs are often duplicated and the functional specialization of multigenic families will be of particular interest for future studies.
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Affiliation(s)
- Eloi R Verrier
- INRA, Fish Infection and Immunity, Molecular Virology and Immunology, Domaine de Vilvert, 78352 Jouy en Josas, France
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Yang PJ, Wu CX, Li W, Fan LH, Lin G, Hu CY. Cloning and functional analysis of PKZ (PKR-like) from grass carp (Ctenopharyngodon idellus). FISH & SHELLFISH IMMUNOLOGY 2011; 31:1173-1178. [PMID: 22008285 DOI: 10.1016/j.fsi.2011.10.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 09/14/2011] [Accepted: 10/06/2011] [Indexed: 05/31/2023]
Abstract
The new teleost fish PKZ (PKR-like) full-length cDNA (GU299765) had been cloned and identified from grass carp (Ctenopharyngodon idellus). The cDNA of grass carp PKZ (CiPKZ) has 2185 bp in length with a largest open reading frame (ORF) encoding 513aa. CiPKZ possesses a conserved C-terminal catalytic domain of eIF2α kinase family. Within its N-terminal there are two binding domain (Zα) named Zα1 (1-67aa) and Zα2 (81-152aa). BLAST homologous search reveals that CiPKZ has a high-level homology with other fish PKZs and PKRs. Like other fish PKZs and PKRs, CiPKZ is a ubiquitous tissue expression gene that had a very low level of constitutive expression but up-regulated in response to Poly I:C or hot stress (34 °C). For the purpose of searching for the potential function of CiPKZ, we obtained CiPKZ polypeptide via Escherichia coli Rosetta prokaryotic expression and purified with Ni-NTA His-Bind Resin affinity chromatography. CiPKZ polypeptide was used for the test of phosphorylating eIF2αin vitro. The results demonstrated that CiPKZ could be activated by Z-DNA but not by Poly I:C, and with subsequent could phosphorylate eIF2α. Meanwhile, four pcDNA3.1/PKZ recombinant plasmids, including pcDNA3.1/PKZ-wet, pcDNA3.1/PKZ-wet-K198R, pcDNA3.1/PKZ-wet-C, pcDNA3.1/PKZ-wet-C-K198R had been constructed, respectively. Mouse Myeloma cells (Sp2/0) and Human Umbilical Vein Endothelial Cells (HUVEC) were transiently cotransfected with pcDNA3.1/PKZ recombinant plasmid and PGL-3-promoter plasmid. The results revealed that CiPKZ could greatly decrease luciferase level in these cells. Zα and the K198 amino acid residue may play a key role in its function.
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Affiliation(s)
- Peng-Jie Yang
- Department of Bioscience, College of Life Science and Food Engineering, Nanchang University, Nanchang 330031, China
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Cooperative roles of fish protein kinase containing Z-DNA binding domains and double-stranded RNA-dependent protein kinase in interferon-mediated antiviral response. J Virol 2011; 85:12769-80. [PMID: 21937641 DOI: 10.1128/jvi.05849-11] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The double-stranded RNA (dsRNA)-dependent protein kinase (PKR) inhibits protein synthesis by phosphorylating eukaryotic translation initiation factor 2α (eIF2α). In fish species, in addition to PKR, there exists a PKR-like protein kinase containing Z-DNA binding domains (PKZ). However, the antiviral role of fish PKZ and the functional relationship between fish PKZ and PKR remain unknown. Here we confirmed the coexpression of fish PKZ and PKR proteins in Carassius auratus blastula embryonic (CAB) cells and identified them as two typical interferon (IFN)-inducible eIF2α kinases, both of which displayed an ability to inhibit virus replication. Strikingly, fish IFN or all kinds of IFN stimuli activated PKZ and PKR to phosphorylated eIF2α. Overexpression of both fish kinases together conferred much more significant inhibition of virus replication than overexpression of either protein, whereas morpholino knockdown of both made fish cells more vulnerable to virus infection than knockdown of either. The antiviral ability of fish PKZ was weaker than fish PKR, which correlated with its lower ability to phosphorylate eIF2α than PKR. Moreover, the independent association of fish PKZ or PKR reveals that each of them formed homodimers and that fish PKZ phosphorylated eIF2α independently on fish PKR and vice versa. These results suggest that fish PKZ and PKR play a nonredundant but cooperative role in IFN antiviral response.
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Rothenburg S, Chinchar VG, Dever TE. Characterization of a ranavirus inhibitor of the antiviral protein kinase PKR. BMC Microbiol 2011; 11:56. [PMID: 21418572 PMCID: PMC3068933 DOI: 10.1186/1471-2180-11-56] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 03/18/2011] [Indexed: 01/06/2023] Open
Abstract
Background Ranaviruses (family Iridoviridae) are important pathogens of lower vertebrates. However, little is known about how they circumvent the immune response of their hosts. Many ranaviruses contain a predicted protein, designated vIF2α, which shows homology with the eukaryotic translation initiation factor 2α. In analogy to distantly related proteins found in poxviruses vIF2α might act as an inhibitor of the antiviral protein kinase PKR. Results We have characterized the function of vIF2α from Rana catesbeiana virus Z (RCV-Z). Multiple sequence alignments and secondary structure prediction revealed homology of vIF2α with eIF2α throughout the S1-, helical- and C-terminal domains. Genetic and biochemical analyses showed that vIF2α blocked the toxic effects of human and zebrafish PKR in a heterologous yeast system. Rather than complementing eIF2α function, vIF2α acted in a manner comparable to the vaccinia virus (VACV) K3L protein (K3), a pseudosubstrate inhibitor of PKR. Both vIF2α and K3 inhibited human PKR-mediated eIF2α phosphorylation, but not PKR autophosphorylation on Thr446. In contrast the E3L protein (E3), another poxvirus inhibitor of PKR, inhibited both Thr446 and eIF2α Ser51 phosphorylation. Interestingly, phosphorylation of eIF2α by zebrafish PKR was inhibited by vIF2α and E3, but not by K3. Effective inhibition of PKR activity coincided with increased PKR expression levels, indicative of relieved autoinhibition of PKR expression. Experiments with vIF2α deletion constructs, showed that both the N-terminal and helical domains were sufficient for inhibition of PKR, whereas the C-terminal domain was dispensable. Conclusions Our results show that RCV-Z vIF2α is a functional inhibitor of human and zebrafish PKR, and probably functions in similar fashion as VACV K3. This constitutes an important step in understanding the interaction of ranaviruses and the host innate immune system.
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Affiliation(s)
- Stefan Rothenburg
- Laboratory of Gene Regulation and Development, NICHD, National Institutes of Health, Bethesda, MD 20892, USA.
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Innate immune evasion mediated by the Ambystoma tigrinum virus eukaryotic translation initiation factor 2alpha homologue. J Virol 2011; 85:5061-9. [PMID: 21389122 DOI: 10.1128/jvi.01488-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ranaviruses (family Iridoviridae, genus Ranavirus) are large, double-stranded DNA (dsDNA) viruses whose replication is restricted to ectothermic vertebrates. Many highly pathogenic members of the genus Ranavirus encode a homologue of the eukaryotic translation initiation factor 2α (eIF2α). Data in a heterologous vaccinia virus system suggest that the Ambystoma tigrinum virus (ATV) eIF2α homologue (vIF2αH; open reading frame [ORF] 57R) is involved in evading the host innate immune response by degrading the interferon-inducible, dsRNA-activated protein kinase, PKR. To test this hypothesis directly, the ATV vIF2αH gene (ORF 57R) was deleted by homologous recombination, and a selectable marker was inserted in its place. The ATVΔ57R virus has a small plaque phenotype and is 8-fold more sensitive to interferon than wild-type ATV (wtATV). Infection of fish cells with the ATVΔ57R virus leads to eIF2α phosphorylation, in contrast to infection with wtATV, which actively inhibits eIF2α phosphorylation. The inability of ATVΔ57R to prevent phosphorylation of eIF2α correlates with degradation of fish PKZ, an interferon-inducible enzyme that is closely related to mammalian PKR. In addition, salamanders infected with ATVΔ57R displayed an increased time to death compared to that of wtATV-infected salamanders. Therefore, in a biologically relevant system, the ATV vIF2αH gene acts as an innate immune evasion factor, thereby enhancing virus pathogenesis.
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Harashima A, Guettouche T, Barber GN. Phosphorylation of the NFAR proteins by the dsRNA-dependent protein kinase PKR constitutes a novel mechanism of translational regulation and cellular defense. Genes Dev 2010; 24:2640-53. [PMID: 21123651 DOI: 10.1101/gad.1965010] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Here, we describe a new mechanism of host defense that involves the nuclear factors associated with dsRNA (NFAR1 [90 kDa] and NFAR2 [110 kDa]), which constitute part of the shuttling ribonuclear protein (RNP) complex. Activation of the dsRNA-activated protein kinase PKR by viral RNA enabled phosphorylation of NFAR1 and NFAR2 on Thr 188 and Thr 315, an event found to be evolutionarily conserved in Xenopus. Phosphorylated NFAR1 and NFAR2 became dissociated from nuclear factor 45 (NF45), which was requisite for NFAR reshuttling, causing the NFARs to be retained on ribosomes, associate with viral transcripts, and impede viral replication. Cre-loxP animals with depletion of the NFARs in the thymus were exquisitely sensitive to the cytoplasmic replicating virus VSV (vesicular stomatitis virus). Thus, the NFARs constitute a novel, conserved mechanism of host defense used by the cell to detect and impede aberrant translation events.
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Affiliation(s)
- Ai Harashima
- Department of Medicine, University of Miami School of Medicine, Florida 33136, USA
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Sadler AJ. Orchestration of the activation of protein kinase R by the RNA-binding motif. J Interferon Cytokine Res 2010; 30:195-204. [PMID: 20377414 DOI: 10.1089/jir.2010.0005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The protein kinase R (PKR) constitutes part of the host antiviral response. PKR activation is regulated by the N-terminus of protein, which encodes tandem RNA-binding motifs (RBMs). The full capabilities of RBMs from PKR and other proteins have surpassed the narrow specificities initially determined as merely binding double-stranded RNA. Recognition of the increased affinity of the RBM for additional RNA species has established an immunological distinction by which PKR can detect exogenous RNAs, as well as identified PKR-mediated expression of specific endogenous genes. Furthermore, as RBMs also mediate interactions with other proteins, including PKR itself, this motif connects PKR to the broader RNA metabolism. Given the fundamental importance of protein-RNA interactions, not only in the innate immune response to intracellular pathogens, but also to coordinate the cellular replication machinery, there is considerable interest in the mechanisms by which proteins recognize and respond to RNA. This review appraises our understanding of how PKR activity is modulated by the RBMs.
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Affiliation(s)
- Anthony J Sadler
- Monash Institute of Medical Research, Monash University, Melbourne, Australia
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Hernández G, Altmann M, Lasko P. Origins and evolution of the mechanisms regulating translation initiation in eukaryotes. Trends Biochem Sci 2010; 35:63-73. [DOI: 10.1016/j.tibs.2009.10.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 10/27/2009] [Accepted: 10/28/2009] [Indexed: 02/08/2023]
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Feng CY, Rise ML. Characterization and expression analyses of anti-apoptotic Bcl-2-like genes NR-13, Mcl-1, Bcl-X1, and Bcl-X2 in Atlantic cod (Gadus morhua). Mol Immunol 2010; 47:763-84. [DOI: 10.1016/j.molimm.2009.10.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 10/07/2009] [Accepted: 10/13/2009] [Indexed: 12/16/2022]
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