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Catalán-Tatjer D, Tzimou K, Nielsen LK, Lavado-García J. Unravelling the essential elements for recombinant adeno-associated virus (rAAV) production in animal cell-based platforms. Biotechnol Adv 2024; 73:108370. [PMID: 38692443 DOI: 10.1016/j.biotechadv.2024.108370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 04/05/2024] [Accepted: 04/27/2024] [Indexed: 05/03/2024]
Abstract
Recombinant adeno-associated viruses (rAAVs) stand at the forefront of gene therapy applications, holding immense significance for their safe and efficient gene delivery capabilities. The constantly increasing and unmet demand for rAAVs underscores the need for a more comprehensive understanding of AAV biology and its impact on rAAV production. In this literature review, we delved into AAV biology and rAAV manufacturing bioprocesses, unravelling the functions and essentiality of proteins involved in rAAV production. We discuss the interconnections between these proteins and how they affect the choice of rAAV production platform. By addressing existing inconsistencies, literature gaps and limitations, this review aims to define a minimal set of genes that are essential for rAAV production, providing the potential to advance rAAV biomanufacturing, with a focus on minimizing the genetic load within rAAV-producing cells.
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Affiliation(s)
- David Catalán-Tatjer
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark
| | - Konstantina Tzimou
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark
| | - Lars K Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark; Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Australia
| | - Jesús Lavado-García
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark.
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2
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Kim JH, Lee CH, Lee SW. Adenovirus VA RNAs impair maturation of primary microRNA. J Gene Med 2023; 25:e3564. [PMID: 37434327 DOI: 10.1002/jgm.3564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 05/12/2023] [Accepted: 06/22/2023] [Indexed: 07/13/2023] Open
Abstract
BACKGROUND Adenovirus expresses two non-coding virus-associated (VA) RNAs: VA I RNA and VA II RNA. Adenovirus-expressed VA RNAs interfere with the microRNA (miRNA) pathway by competing with precursor miRNAs. The processing pattern of primary miRNA (pri-miRNA) and factors to affect its processing are not exactly known when using adenovirus for the delivery of pri-miRNA. METHODS To observe pri-miRNA processing, plasmid construct encoding pri-miRNA was co-transfected with VA I/II RNA expression plasmid, or recombinant adenovirus encoding pri-miRNA was generated and infected. Levels of miRNAs, VA I RNA and VA II RNA were analyzed by a quantitative real-time PCR (RT-PCR). VA I-II full-length RNA was analyzed by a RT-PCR. RNA immunoprecipitation analysis to pull-down the VA I-II full-length RNA binding with Drosha was conducted with Drosha antibody. RESULTS pri-miRNA was normally processed into mature miRNA when it was expressed in cells using plasmid. However, miRNA maturation was impaired when pri-miRNA was delivered and expressed using adenovirus. Of note, pri-miRNA processing was observed to be blocked by VA RNA expression. Such blocked processing could be recovered by introducing antisense RNA of VA RNA, anti-3'VA RNA. In addition, VA RNAs were transcribed into VA I-II full-length RNA, which was found to bind and sequester Drosha. CONCLUSIONS Adenovirus infection downregulated the processing of pri-miRNAs in cells, and such downregulation could be derived from VA I-II full-length RNAs in pri-miRNA-like form through competitively binding to Drosha protein. These results indicated that the expression of adenovirus VA RNAs should be inhibited for successful delivery and expression of pri-miRNA or shRNA in cells using adenovirus.
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Affiliation(s)
- Ji Hyun Kim
- R&D Center, Rznomics Inc., Seongnam, Republic of Korea
| | - Chang Ho Lee
- Department of Bioconvergence Engineering, Research Institute of Advanced Omics, Dankook University, Yongin, Republic of Korea
| | - Seong-Wook Lee
- R&D Center, Rznomics Inc., Seongnam, Republic of Korea
- Department of Bioconvergence Engineering, Research Institute of Advanced Omics, Dankook University, Yongin, Republic of Korea
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3
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Punga T, Darweesh M, Akusjärvi G. Synthesis, Structure, and Function of Human Adenovirus Small Non-Coding RNAs. Viruses 2020; 12:v12101182. [PMID: 33086737 PMCID: PMC7589676 DOI: 10.3390/v12101182] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 12/25/2022] Open
Abstract
Human adenoviruses (HAdVs) are common pathogens causing a variety of respiratory, ocular and gastrointestinal diseases. To accomplish their efficient replication, HAdVs take an advantage of viral small non-coding RNAs (sncRNAs), which have multiple roles during the virus lifecycle. Three of the best-characterized HAdV sncRNAs; VA RNA, mivaRNA and MLP-TSS-sRNA will be discussed in the present review. Even though VA RNA has been extensively characterized during the last 60 years, this multifunctional molecule continues to surprise us as more of its structural secrets unfold. Likely, the recent developments on mivaRNA and MLP-TSS-sRNA synthesis and function highlight the importance of these sncRNA in virus replication. Collectively, we will summarize the old and new knowledge about these three viral sncRNAs with focus on their synthesis, structure and functions.
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Hood IV, Gordon JM, Bou-Nader C, Henderson FE, Bahmanjah S, Zhang J. Crystal structure of an adenovirus virus-associated RNA. Nat Commun 2019; 10:2871. [PMID: 31253805 PMCID: PMC6599070 DOI: 10.1038/s41467-019-10752-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/27/2019] [Indexed: 12/20/2022] Open
Abstract
Adenovirus Virus-Associated (VA) RNAs are the first discovered viral noncoding RNAs. By mimicking double-stranded RNAs (dsRNAs), the exceptionally abundant, multifunctional VA RNAs sabotage host machineries that sense, transport, process, or edit dsRNAs. How VA-I suppresses PKR activation despite its strong dsRNA character, and inhibits the crucial antiviral kinase to promote viral translation, remains largely unknown. Here, we report a 2.7 Å crystal structure of VA-I RNA. The acutely bent VA-I features an unusually structured apical loop, a wobble-enriched, coaxially stacked apical and tetra-stems necessary and sufficient for PKR inhibition, and a central domain pseudoknot that resembles codon-anticodon interactions and prevents PKR activation by VA-I. These global and local structural features collectively define VA-I as an archetypal PKR inhibitor made of RNA. The study provides molecular insights into how viruses circumnavigate cellular rules of self vs non-self RNAs to not only escape, but further compromise host innate immunity.
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Affiliation(s)
- Iris V Hood
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Jackson M Gordon
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Charles Bou-Nader
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Frances E Henderson
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Soheila Bahmanjah
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, 50 South Drive, Room 4503, Bethesda, MD, 20892, USA.
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5
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Bou-Nader C, Gordon JM, Henderson FE, Zhang J. The search for a PKR code-differential regulation of protein kinase R activity by diverse RNA and protein regulators. RNA (NEW YORK, N.Y.) 2019; 25:539-556. [PMID: 30770398 PMCID: PMC6467004 DOI: 10.1261/rna.070169.118] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The interferon-inducible protein kinase R (PKR) is a key component of host innate immunity that restricts viral replication and propagation. As one of the four eIF2α kinases that sense diverse stresses and direct the integrated stress response (ISR) crucial for cell survival and proliferation, PKR's versatile roles extend well beyond antiviral defense. Targeted by numerous host and viral regulators made of RNA and proteins, PKR is subject to multiple layers of endogenous control and external manipulation, driving its rapid evolution. These versatile regulators include not only the canonical double-stranded RNA (dsRNA) that activates the kinase activity of PKR, but also highly structured viral, host, and artificial RNAs that exert a full spectrum of effects. In this review, we discuss our deepening understanding of the allosteric mechanism that connects the regulatory and effector domains of PKR, with an emphasis on diverse structured RNA regulators in comparison to their protein counterparts. Through this analysis, we conclude that much of the mechanistic details that underlie this RNA-regulated kinase await structural and functional elucidation, upon which we can then describe a "PKR code," a set of structural and chemical features of RNA that are both descriptive and predictive for their effects on PKR.
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Affiliation(s)
- Charles Bou-Nader
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Jackson M Gordon
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Frances E Henderson
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | - Jinwei Zhang
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
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6
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Gal-Ben-Ari S, Barrera I, Ehrlich M, Rosenblum K. PKR: A Kinase to Remember. Front Mol Neurosci 2019; 11:480. [PMID: 30686999 PMCID: PMC6333748 DOI: 10.3389/fnmol.2018.00480] [Citation(s) in RCA: 162] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/10/2018] [Indexed: 12/26/2022] Open
Abstract
Aging is a major risk factor for many diseases including metabolic syndrome, cancer, inflammation, and neurodegeneration. Identifying mechanistic common denominators underlying the impact of aging is essential for our fundamental understanding of age-related diseases and the possibility to propose new ways to fight them. One can define aging biochemically as prolonged metabolic stress, the innate cellular and molecular programs responding to it, and the new stable or unstable state of equilibrium between the two. A candidate to play a role in the process is protein kinase R (PKR), first identified as a cellular protector against viral infection and today known as a major regulator of central cellular processes including mRNA translation, transcriptional control, regulation of apoptosis, and cell proliferation. Prolonged imbalance in PKR activation is both affected by biochemical and metabolic parameters and affects them in turn to create a feedforward loop. Here, we portray the central role of PKR in transferring metabolic information and regulating cellular function with a focus on cancer, inflammation, and brain function. Later, we integrate information from open data sources and discuss current knowledge and gaps in the literature about the signaling cascades upstream and downstream of PKR in different cell types and function. Finally, we summarize current major points and biological means to manipulate PKR expression and/or activation and propose PKR as a therapeutic target to shift age/metabolic-dependent undesired steady states.
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Affiliation(s)
- Shunit Gal-Ben-Ari
- Laboratory of Molecular and Cellular Mechanisms Underlying Learning and Memory, Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Iliana Barrera
- Laboratory of Molecular and Cellular Mechanisms Underlying Learning and Memory, Sagol Department of Neurobiology, University of Haifa, Haifa, Israel
| | - Marcelo Ehrlich
- Laboratory of Intracellular Trafficking and Signaling, School of Molecular Cell Biology & Biotechnology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Kobi Rosenblum
- Laboratory of Molecular and Cellular Mechanisms Underlying Learning and Memory, Sagol Department of Neurobiology, University of Haifa, Haifa, Israel.,Center for Gene Manipulation in the Brain, University of Haifa, Haifa, Israel
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7
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Dzananovic E, McKenna SA, Patel TR. Viral proteins targeting host protein kinase R to evade an innate immune response: a mini review. Biotechnol Genet Eng Rev 2018; 34:33-59. [PMID: 29716441 DOI: 10.1080/02648725.2018.1467151] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The innate immune system offers a first line of defense by neutralizing foreign pathogens such as bacteria, fungi, and viruses. These pathogens express molecules (RNA and proteins) that have discrete structures, known as the pathogen-associated molecular patterns that are recognized by a highly specialized class of host proteins called pattern recognition receptors to facilitate the host's immune response against infection. The RNA-dependent Protein Kinase R (PKR) is one of the host's pattern recognition receptors that is a key component of an innate immune system. PKR recognizes imperfectly double-stranded non-coding viral RNA molecules via its N-terminal double-stranded RNA binding motifs, undergoes phosphorylation of the C-terminal kinase domain, ultimately resulting in inhibition of viral protein translation by inhibiting the guanine nucleotide exchange activity of eukaryotic initiation factor 2α. Not surprisingly, viruses have evolved mechanisms by which viral non-coding RNA or protein molecules inhibit PKR's activation and/or its downstream activity to allow viral replication. In this review, we will highlight the role of viral proteins in inhibiting PKR's activity and summarize currently known mechanisms by which viral proteins execute such inhibitory activity.
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Affiliation(s)
- Edis Dzananovic
- a Plant Pathology, Plant Protection and Molecular Biology , Agriculture and Agri-Food Canada , Saskatoon , Canada
| | - Sean A McKenna
- b Department of Chemistry, Manitoba Institute for Materials, Department of Biochemistry and Medical Genetics , University of Manitoba , Winnipeg , Canada
| | - Trushar R Patel
- c Department of Chemistry and Biochemistry , Alberta RNA Research and Training Institute, University of Lethbridge , Lethbridge , Canada.,d DiscoveryLab, Faculty of Medicine & Dentistry , University of Alberta , Edmonton , Canada.,e Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine , University of Calgary , Calgary , Canada
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8
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Impact of the structural integrity of the three-way junction of adenovirus VAI RNA on PKR inhibition. PLoS One 2017; 12:e0186849. [PMID: 29053745 PMCID: PMC5650172 DOI: 10.1371/journal.pone.0186849] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/09/2017] [Indexed: 02/06/2023] Open
Abstract
Highly structured RNA derived from viral genomes is a key cellular indicator of viral infection. In response, cells produce the interferon inducible RNA-dependent protein kinase (PKR) that, when bound to viral dsRNA, phosphorylates eukaryotic initiation factor 2α and attenuates viral protein translation. Adenovirus can evade this line of defence through transcription of a non-coding RNA, VAI, an inhibitor of PKR. VAI consists of three base-paired regions that meet at a three-way junction; an apical stem responsible for the interaction with PKR, a central stem required for inhibition, and a terminal stem. Recent studies have highlighted the potential importance of the tertiary structure of the three-way junction to PKR inhibition by enabling interaction between regions of the central and terminal stems. To further investigate the role of the three-way junction, we characterized the binding affinity and inhibitory potential of central stem mutants designed to introduce subtle alterations. These results were then correlated with small-angle X-ray scattering solution studies and computational tertiary structural models. Our results demonstrate that while mutations to the central stem have no observable effect on binding affinity to PKR, mutations that appear to disrupt the structure of the three-way junction prevent inhibition of PKR. Therefore, we propose that instead of simply sequestering PKR, a specific structural conformation of the PKR-VAI complex may be required for inhibition.
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9
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Launer-Felty K, Wong CJ, Cole JL. Structural analysis of adenovirus VAI RNA defines the mechanism of inhibition of PKR. Biophys J 2015; 108:748-57. [PMID: 25650941 DOI: 10.1016/j.bpj.2014.12.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 12/01/2014] [Accepted: 12/08/2014] [Indexed: 01/24/2023] Open
Abstract
Protein kinase R (PKR) is activated by dsRNA produced during virus replication and plays a major role in the innate immunity response to virus infection. In response, viruses have evolved multiple strategies to evade PKR. Adenovirus virus-associated RNA-I (VAI) is a short, noncoding transcript that functions as an RNA decoy to sequester PKR in an inactive state. VAI consists of an apical stem-loop, a highly structured central domain, and a terminal stem. Chemical probing and mutagenesis demonstrate that the central domain is stabilized by a pseudoknot. A structural model of VAI was obtained from constraints derived from chemical probing and small angle x-ray scattering (SAXS) measurements. VAI adopts a flat, extended conformation with the apical and terminal stems emanating from a protuberance in the center. This model reveals how the apical stem and central domain assemble to produce an extended duplex that is precisely tuned to bind a single PKR monomer with high affinity, thereby inhibiting activation of PKR by viral dsRNA.
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Affiliation(s)
- Katherine Launer-Felty
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut
| | - C Jason Wong
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut
| | - James L Cole
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut; Department of Chemistry, University of Connecticut, Storrs, Connecticut.
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10
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Vachon VK, Conn GL. Adenovirus VA RNA: An essential pro-viral non-coding RNA. Virus Res 2015; 212:39-52. [PMID: 26116898 DOI: 10.1016/j.virusres.2015.06.018] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 06/15/2015] [Accepted: 06/17/2015] [Indexed: 12/25/2022]
Abstract
Adenovirus (AdV) 'virus-associated' RNAs (VA RNAs) are exceptionally abundant (up to 10(8)copies/cell), heterogeneous, non-coding RNA transcripts (∼ 150-200 nucleotides). The predominant species, VA RNAI, is best recognized for its essential function in relieving the cellular anti-viral blockade of protein synthesis through inhibition of the double-stranded RNA-activated protein kinase (PKR). More recent evidence has revealed that VA RNAs also interfere with several other host cell processes, in part by virtue of the high level to which they accumulate. Following transcription by cellular RNA polymerase III, VA RNAs saturate the nuclear export protein Exportin 5 (Exp5) and the cellular endoribonculease Dicer, interfering with pre-micro (mi)RNA export and miRNA biogenesis, respectively. Dicer-processed VA RNA fragments are incorporated into the RNA-induced silencing complex (RISC) as 'mivaRNAs', where they may specifically target cellular genes. VA RNAI also interacts with other innate immune proteins, including OAS1. While intact VA RNAI has the paradoxical effect of activating OAS1, a non-natural VA RNAI construct lacking the entire Terminal Stem has been reported to be a pseudoinhibitor of OAS1. Here, we show that a VA RNAI construct corresponding to an authentic product of Dicer processing similarly fails to activate OAS1 but also retains only a modest level of inhibitory activity against PKR in contrast to the non-natural deletion construct. These findings underscore the complexity of the arms race between virus and host, and highlight the need for further exploration of the impact of VA RNAI interactions with host defenses on the outcome of AdV infection beyond that of well-established PKR inhibition. Additional contributions of VA RNAI heterogeneity resulting from variations in transcription initiation and termination to each of these functions remain open questions that are discussed here.
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Affiliation(s)
- Virginia K Vachon
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA; Microbiology and Molecular Genetics (MMG) Program, Graduate Division of Biological and Biomedical Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.
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11
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Identification of RISC-associated adenoviral microRNAs, a subset of their direct targets, and global changes in the targetome upon lytic adenovirus 5 infection. J Virol 2014; 89:1608-27. [PMID: 25410853 DOI: 10.1128/jvi.02336-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED Adenoviruses encode a set of highly abundant microRNAs (mivaRNAs), which are generated by Dicer-mediated cleavage of the larger noncoding virus-associated RNAs (VA RNAs) I and II. We performed deep RNA sequencing to thoroughly investigate the relative abundance of individual single strands of mivaRNA isoforms in human A549 cells lytically infected with human adenovirus 5 (Ad5) at physiologically relevant multiplicities of infection (MOIs). In addition, we investigated their relative abundance in the endogenous RNA-induced silencing complexes (RISCs). The occupation of endogenous RISCs by mivaRNAs turned out to be pronounced but not as dominant as previously inferred from experiments with AGO2-overexpressing cells infected at high MOIs. In parallel, levels of RISC-incorporated mRNAs were investigated as well. Analysis of mRNAs enriched in RISCs in Ad5-infected cells revealed that only mRNAs with complementarity to the seed sequences of mivaRNAs derived from VA RNAI but not VA RNAII were overrepresented among them, indicating that only mivaRNAs derived from VA RNAI are likely to contribute substantially to the posttranscriptional downregulation of host gene expression. Furthermore, to generate a comprehensive picture of the entire transcriptome/targetome in lytically infected cells, we determined changes in cellular miRNA levels in both total RNA and RISC RNA as well, and bioinformatical analysis of mRNAs of total RNA/RISC fractions revealed a general, genome-wide trend toward detargeting of cellular mRNAs upon infection. Lastly, we identified the direct targets of both single strands of a VA RNAI-derived mivaRNA that constituted one of the two most abundant isoforms in RISCs of lytically infected A549 cells. IMPORTANCE Viral and cellular miRNAs have been recognized as important players in virus-host interactions. This work provides the currently most comprehensive picture of the entire mRNA/miRNA transcriptome and of the complete RISC targetome during lytic adenovirus infection and thus represents the basis for a deeper understanding of the interplay between the virus and the cellular RNA interference machinery. Our data suggest that, at least in the model system that was employed, lytic infection by Ad5 is accompanied by a measurable global net detargeting effect on cellular mRNAs, and analysis of RISC-associated viral small RNAs revealed that the VA RNAs are the only source of virus-encoded miRNAs. Moreover, this work allows to assess the power of individual viral miRNAs to regulate cellular gene expression and provides a list of proven and putative direct targets of these miRNAs, which is of importance, given the fact that information about validated targets of adenovirus-encoded miRNAs is scarce.
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12
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Hudson WH, Pickard MR, de Vera IMS, Kuiper EG, Mourtada-Maarabouni M, Conn GL, Kojetin DJ, Williams GT, Ortlund EA. Conserved sequence-specific lincRNA-steroid receptor interactions drive transcriptional repression and direct cell fate. Nat Commun 2014; 5:5395. [PMID: 25377354 DOI: 10.1038/ncomms6395] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 09/26/2014] [Indexed: 01/01/2023] Open
Abstract
The majority of the eukaryotic genome is transcribed, generating a significant number of long intergenic noncoding RNAs (lincRNAs). Although lincRNAs represent the most poorly understood product of transcription, recent work has shown lincRNAs fulfill important cellular functions. In addition to low sequence conservation, poor understanding of structural mechanisms driving lincRNA biology hinders systematic prediction of their function. Here we report the molecular requirements for the recognition of steroid receptors (SRs) by the lincRNA growth arrest-specific 5 (Gas5), which regulates steroid-mediated transcriptional regulation, growth arrest and apoptosis. We identify the functional Gas5-SR interface and generate point mutations that ablate the SR-Gas5 lincRNA interaction, altering Gas5-driven apoptosis in cancer cell lines. Further, we find that the Gas5 SR-recognition sequence is conserved among haplorhines, with its evolutionary origin as a splice acceptor site. This study demonstrates that lincRNAs can recognize protein targets in a conserved, sequence-specific manner in order to affect critical cell functions.
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Affiliation(s)
- William H Hudson
- 1] Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA [2] Discovery and Developmental Therapeutics, Winship Cancer Institute, Atlanta, Georgia 30322, USA
| | - Mark R Pickard
- Institute of Science and Technology in Medicine, School of Life Sciences, Keele University, Keele ST5 5BG, UK
| | - Ian Mitchelle S de Vera
- Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, Florida 33458 USA
| | - Emily G Kuiper
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Mirna Mourtada-Maarabouni
- Institute of Science and Technology in Medicine, School of Life Sciences, Keele University, Keele ST5 5BG, UK
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Douglas J Kojetin
- Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, Florida 33458 USA
| | - Gwyn T Williams
- Institute of Science and Technology in Medicine, School of Life Sciences, Keele University, Keele ST5 5BG, UK
| | - Eric A Ortlund
- 1] Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, USA [2] Discovery and Developmental Therapeutics, Winship Cancer Institute, Atlanta, Georgia 30322, USA
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13
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Wilson JL, Vachon VK, Sunita S, Schwartz SL, Conn GL. Dissection of the adenoviral VA RNAI central domain structure reveals minimum requirements for RNA-mediated inhibition of PKR. J Biol Chem 2014; 289:23233-23245. [PMID: 24970889 DOI: 10.1074/jbc.m114.550046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Virus-associated RNA I (VA RNAI) is a short (∼160-nucleotide) non-coding RNA transcript employed by adenoviruses to subvert the innate immune system protein double-stranded RNA-activated protein kinase (PKR). The central domain of VA RNAI is proposed to contain a complex tertiary structure that contributes to its optimal inhibitory activity against PKR. Here we use a combination of VA RNAI mutagenesis, structural analyses, as well as PKR activity and binding assays to dissect this tertiary structure and assess its functional role. Our results support the existence of a pH- and Mg(2+)-dependent tertiary structure involving pseudoknot formation within the central domain. Unexpectedly, this structure appears to play no direct role in PKR inhibition. Deletion of central domain sequences within a minimal but fully active construct lacking the tertiary structure reveals a crucial role in PKR binding and inhibition for nucleotides in the 5' half of the central domain. Deletion of the central domain 3' half also significantly impacts activity but appears to arise indirectly by reducing its capacity to assist in optimally presenting the 5' half sequence. Collectively, our results identify regions of VA RNAI critical for PKR inhibition and reveal that the requirements for an effective RNA inhibitor of PKR are simpler than appreciated previously.
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Affiliation(s)
- Jo L Wilson
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Virginia K Vachon
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - S Sunita
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Samantha L Schwartz
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322.
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14
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Mohamed YM, Bangphoomi N, Yamane D, Suda Y, Kato K, Horimoto T, Akashi H. Physical interaction between bovine viral diarrhea virus nonstructural protein 4A and adenosine deaminase acting on RNA (ADAR). Arch Virol 2014; 159:1735-41. [DOI: 10.1007/s00705-014-1997-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 01/19/2014] [Indexed: 11/24/2022]
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15
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Launer-Felty K, Cole JL. Domain interactions in adenovirus VAI RNA mediate high-affinity PKR binding. J Mol Biol 2014; 426:1285-95. [PMID: 24394721 DOI: 10.1016/j.jmb.2013.12.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 12/16/2013] [Accepted: 12/17/2013] [Indexed: 10/25/2022]
Abstract
Protein kinase R (PKR) is a component of the innate immunity antiviral pathway. PKR is activated upon binding to double-stranded RNA (dsRNA) to undergo dimerization and autophosphorylation. Adenovirus-associated RNA I (VAI) is a short, non-coding transcript whose major function is to inhibit the activity of PKR. VAI contains three domains: an apical stem-loop, a highly structured central domain, and a terminal stem. Previous studies have localized PKR binding to the apical stem and to the central domain. However, the molecular mechanism for inhibition of PKR is not known. We have characterized the stoichiometry and affinity of PKR binding to VAI and several domain constructs using analytical ultracentrifugation and correlated VAI binding and PKR inhibition. Although PKR binding to simple dsRNAs is not regulated by divalent ion, analysis of the interaction of the isolated dsRNA binding domain with VAI reveals that the binding affinity is enhanced by divalent ion. Dissection of VAI into its constituent domains indicates that none of the isolated domains retains the PKR binding affinity or inhibitory potency of the full-length RNA. PKR is capable of binding the isolated terminal stem, but deletion of this domain from VAI does not affect PKR binding or inhibition. These results indicate that both the apical stem and the central domain are required to form a high-affinity PKR binding site. Our data support a model whereby VAI functions as a PKR inhibitor because it binds a monomer tightly but does not facilitate dimerization.
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Affiliation(s)
- Katherine Launer-Felty
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - James L Cole
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA; Department of Chemistry, University of Connecticut, Storrs, CT 06269, USA.
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16
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Dzananovic E, Patel TR, Chojnowski G, Boniecki MJ, Deo S, McEleney K, Harding SE, Bujnicki JM, McKenna SA. Solution conformation of adenovirus virus associated RNA-I and its interaction with PKR. J Struct Biol 2013; 185:48-57. [PMID: 24291322 DOI: 10.1016/j.jsb.2013.11.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 11/12/2013] [Accepted: 11/23/2013] [Indexed: 11/29/2022]
Abstract
Adenovirus virus-associated RNA (VAI) provides protection against the host antiviral response in part by inhibiting the interferon-induced double stranded RNA-activated protein kinase (PKR). VAI consists of three base-paired regions; the apical stem responsible for the interaction with double-stranded RNA binding motifs (dsRBMs) of PKR, the central stem required for inhibition, and the terminal stem. The solution conformation of VAI and VAI lacking the terminal stem were determined using SAXS that suggested extended conformations that are in agreement with their secondary structures. Solution conformations of VAI lacking the terminal stem in complex with the dsRBMs of PKR indicated that the apical stem interacts with both dsRNA-binding motifs whereas the central stem does not. Hydrodynamic properties calculated from ab initio models were compared to experimentally determined parameters for model validation. Furthermore, SAXS envelopes were used as a constraint for the in silico modeling of tertiary structure for RNA and RNA-protein complex. Finally, full-length PKR was also studied, but concentration-dependent changes in hydrodynamic parameters prevented ab initio shape determination. Taken together, results provide an improved structural framework that further our understanding of the role VAI plays in evading host innate immune responses.
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Affiliation(s)
- Edis Dzananovic
- Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Trushar R Patel
- Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada; School of Biosciences, University of Birmingham, Birmingham B152TT, UK
| | - Grzegorz Chojnowski
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. Ks. Trojdena 4, Warsaw 02-109, Poland
| | - Michal J Boniecki
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. Ks. Trojdena 4, Warsaw 02-109, Poland
| | - Soumya Deo
- Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Kevin McEleney
- Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada; Manitoba Institute for Materials, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Stephen E Harding
- NCMH Laboratory, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
| | - Janusz M Bujnicki
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. Ks. Trojdena 4, Warsaw 02-109, Poland; Laboratory of Bioinformatics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, ul. Umultowska 89, Poznan 61-614, Poland
| | - Sean A McKenna
- Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada; Department of Biochemistry and Medical Genetics, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada.
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17
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Punga T, Kamel W, Akusjärvi G. Old and new functions for the adenovirus virus-associated RNAs. Future Virol 2013. [DOI: 10.2217/fvl.13.19] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Adenovirus type 5 encodes two short, highly structured noncoding RNAs, the virus-associated (VA) RNAI and VA RNAII. These RNAs are expressed in large amounts late during a lytic infection. Early studies established an important role for VA RNAI in maintaining efficient translation in late virus-infected cells by blocking activation of the key interferon-induced PKR protein kinase. More recent studies have demonstrated that the VA RNAs also target the RNAi/miRNA pathway. Collectively, available data suggest that the VA RNAs are multifunctional RNAs suppressing the activity of three dsRNA-sensing enzyme systems in human cells. Here, the known functions of the VA RNAs are summarized and the interplay between VA RNA expression and the activity of the interferon and RNAi pathways are discussed in more detail.
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Affiliation(s)
- Tanel Punga
- Department of Medical Biochemistry & Microbiology, Uppsala University, Husargatan 3, BMC Box 582, 75123 Uppsala, Sweden
| | - Wael Kamel
- Department of Medical Biochemistry & Microbiology, Uppsala University, Husargatan 3, BMC Box 582, 75123 Uppsala, Sweden
| | - Göran Akusjärvi
- Department of Medical Biochemistry & Microbiology, Uppsala University, Husargatan 3, BMC Box 582, 75123 Uppsala, Sweden.
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18
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Abstract
In this review, we focus on the roles of long noncoding RNAs (lncRNAs), including cellular and viral lncRNAs, in virus replication in infected cells. We survey the interactions and functions of several cellular lncRNAs such as XIST, HOTAIR, NEAT1, BIC, and several virus-encoded lncRNAs.
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Affiliation(s)
- Quan Zhang
- Molecular Virology Section, Laboratory of Molecular Microbiology, National Institutes of Allergy and Infectious Diseases, the National Institutes of Health, Bethesda, Maryland 20892-0460, USA
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19
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Patel S, Blose JM, Sokoloski JE, Pollack L, Bevilacqua PC. Specificity of the double-stranded RNA-binding domain from the RNA-activated protein kinase PKR for double-stranded RNA: insights from thermodynamics and small-angle X-ray scattering. Biochemistry 2012; 51:9312-22. [PMID: 23140277 DOI: 10.1021/bi300935p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The interferon-inducible, double-stranded (ds) RNA-activated protein kinase (PKR) contains a dsRNA-binding domain (dsRBD) and plays key roles in viral pathogenesis and innate immunity. Activation of PKR is typically mediated by long dsRNA, and regulation of PKR is disfavored by most RNA imperfections, including bulges and internal loops. Herein, we combine isothermal titration calorimetry (ITC), electrophoretic mobility shift assays, and small-angle X-ray scattering (SAXS) to dissect the thermodynamic basis for the specificity of the dsRBD termed "p20" for various RNAs and to detect any RNA conformational changes induced upon protein binding. We monitor binding of p20 to chimeric duplexes containing terminal RNA-DNA hybrid segments and a central dsRNA segment, which was either unbulged ("perfect") or bulged. The ITC data reveal strong binding of p20 to the perfect duplex (K(d) ~ 30 nM) and weaker binding to the bulged duplex (K(d) ~ 2-5 μM). SAXS reconstructions and p(r) distance distribution functions further uncover that p20 induces no significant conformational change in perfect dsRNA but largely straightens bulged dsRNA. Together, these observations support the dsRBD's ability to tightly bind to only A-form RNA and suggest that in a noninfected cell, PKR may be buffered via weak interactions with various bulged and looped RNAs, which it may straighten. This work suggests that PKR-regulating RNAs with complex secondary and tertiary structures likely mimic dsRNA and/or engage portions of PKR outside of the dsRBD.
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Affiliation(s)
- Sunita Patel
- Department of Chemistry and Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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20
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Adenovirus and miRNAs. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1809:660-7. [PMID: 21621026 PMCID: PMC7102710 DOI: 10.1016/j.bbagrm.2011.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 05/05/2011] [Accepted: 05/09/2011] [Indexed: 01/15/2023]
Abstract
Adenovirus infection has a tremendous
impact on the cellular silencing machinery. Adenoviruses express high
amounts of non-coding virus associated (VA) RNAs able to saturate key
factors of the RNA interference (RNAi) processing pathway, such as
Exportin 5 and Dicer. Furthermore, a proportion of VA RNAs is cleaved by
Dicer into viral microRNAs (mivaRNAs) that can saturate Argonaute, an
essential protein for miRNA function. Thus, processing and function of
cellular miRNAs is blocked in adenoviral-infected cells. However, viral
miRNAs actively target the expression of cellular genes involved in
relevant functions such as cell proliferation, DNA repair or RNA
regulation. Interestingly, the cellular silencing machinery is active at
early times post-infection and can be used to control the adenovirus cell
cycle. This is relevant for therapeutic purposes against adenoviral
infections or when recombinant adenoviruses are used as vectors for gene
therapy. Manipulation of the viral genome allows the use of adenoviral
vectors to express therapeutic miRNAs or to be silenced by the RNAi
machinery leading to safer vectors with a specific tropism. This article
is part of a "Special Issue entitled:MicroRNAs in viral gene
regulation".
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21
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Falconer RJ, Collins BM. Survey of the year 2009: applications of isothermal titration calorimetry. J Mol Recognit 2010; 24:1-16. [DOI: 10.1002/jmr.1073] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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22
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Nallagatla SR, Toroney R, Bevilacqua PC. Regulation of innate immunity through RNA structure and the protein kinase PKR. Curr Opin Struct Biol 2010; 21:119-27. [PMID: 21145228 DOI: 10.1016/j.sbi.2010.11.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 11/04/2010] [Accepted: 11/09/2010] [Indexed: 12/25/2022]
Abstract
Molecular recognition of RNA structure is key to innate immunity. The protein kinase PKR differentiates self from non-self by recognition of molecular patterns in RNA. Certain biological RNAs induce autophosphorylation of PKR, activating it to phosphorylate eukaryotic initiation factor 2α (eIF2α), which leads to inhibition of translation. Additional biological RNAs inhibit PKR, while still others have no effect. The aim of this article is to develop a cohesive framework for understanding and predicting PKR function in the context of diverse RNA structure. We present effects of recently characterized viral and cellular RNAs on regulation of PKR, as well as siRNAs. A central conclusion is that assembly of accessible long double-stranded RNA (dsRNA) elements within biological RNAs plays a key role in regulation of PKR kinase. Strategies for forming such elements include RNA dimerization, formation of symmetrical helical defects, A-form dsRNA mimicry, and coaxial stacking of helices.
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Affiliation(s)
- Subba Rao Nallagatla
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Bldg, University Park, PA 16802, USA
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23
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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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24
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Abstract
Protein kinase R (PKR) is a central component of the interferon antiviral defense pathway. Upon binding to dsRNA, PKR undergoes autophosphorylation reactions that activate the kinase, resulting in the inhibition of protein synthesis in virally-infected cells. We have used analytical ultracentrifugation and related biophysical methods to quantitatively characterize the stoichiometries, affinities, and free energy couplings that govern the assembly of the macromolecular complexes in the PKR activation pathway. These studies demonstrate that PKR dimerization play a key role in enzymatic activation and support a model where the role of dsRNA is to bring two or more PKR monomers in close proximity to enhance dimerization.
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Affiliation(s)
- James L Cole
- Department of Molecular and Cell Biology, National Analytical Ultracentrifugation Facility, University of Connecticut, Storrs, CT 06269, USA.
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