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Marschall M, Schütz M, Wild M, Socher E, Wangen C, Dhotre K, Rawlinson WD, Sticht H. Understanding the Cytomegalovirus Cyclin-Dependent Kinase Ortholog pUL97 as a Multifaceted Regulator and an Antiviral Drug Target. Cells 2024; 13:1338. [PMID: 39195228 DOI: 10.3390/cells13161338] [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: 07/04/2024] [Revised: 07/31/2024] [Accepted: 08/06/2024] [Indexed: 08/29/2024] Open
Abstract
Herpesviral protein kinases, such as the therapy-relevant pUL97 of human cytomegalovirus (HCMV), are important for viral replication efficiency as well as pathogenesis, and represent key antiviral drug targets. HCMV pUL97 is a viral cyclin-dependent kinase (CDK) ortholog, as it shares functional and structural properties with human CDKs. Recently, the formation of vCDK/pUL97-cyclin complexes and the phosphorylation of a variety of viral and cellular substrate proteins has been demonstrated. Genetic mapping and structural modeling approaches helped to define two pUL97 interfaces, IF1 and IF2, responsible for cyclin binding. In particular, the regulatory importance of interactions between vCDK/pUL97 and host cyclins as well as CDKs has been highlighted, both as determinants of virus replication and as a novel drug-targeting option. This aspect was substantiated by the finding that virus replication was impaired upon cyclin type H knock-down, and that such host-directed interference also affected viruses resistant to existing therapies. Beyond the formation of binary interactive complexes, a ternary pUL97-cyclin H-CDK7 complex has also been described, and in light of this, an experimental trans-stimulation of CDK7 activity by pUL97 appeared crucial for virus-host coregulation. In accordance with this understanding, several novel antiviral targeting options have emerged. These include kinase inhibitors directed to pUL97, to host CDKs, and to the pUL97-cyclin H interactive complexes. Importantly, a statistically significant drug synergy has recently been reported for antiviral treatment schemes using combinations of pharmacologically relevant CDK7 and vCDK/pUL97 inhibitors, including maribavir. Combined, such findings provide increased options for anti-HCMV control. This review focuses on regulatory interactions of vCDK/pUL97 with the host cyclin-CDK apparatus, and it addresses the functional relevance of these key effector complexes for viral replication and pathogenesis. On this basis, novel strategies of antiviral drug targeting are defined.
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Affiliation(s)
- Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Martin Schütz
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Markus Wild
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Eileen Socher
- Institute of Anatomy, Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Kishore Dhotre
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - William D Rawlinson
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Biomedical Sciences, Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney 2050, Australia
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, FAU, 91054 Erlangen, Germany
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Schütz M, Wangen C, Sommerer M, Kögler M, Eickhoff J, Degenhart C, Klebl B, Naing Z, Egilmezer E, Hamilton ST, Rawlinson WD, Sticht H, Marschall M. Cytomegalovirus cyclin-dependent kinase ortholog vCDK/pUL97 undergoes regulatory interaction with human cyclin H and CDK7 to codetermine viral replication efficiency. Virus Res 2023; 335:199200. [PMID: 37591314 PMCID: PMC10445456 DOI: 10.1016/j.virusres.2023.199200] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 08/19/2023]
Abstract
Human cytomegalovirus (HCMV) infection is shaped by a tightly regulated interplay between viral and cellular proteins. Distinct kinase activities, such as the viral cyclin-dependent kinase ortholog (vCDK) pUL97 and cellular CDK7 are both crucial for efficient viral replication. Previously, we reported that both kinases, vCDK/pUL97 and CDK7, interact with cyclin H, thereby achieving an enhanced level of kinase activity and overall functionality in viral replication. Here we provide a variety of novel results, as generated on a methodologically extended basis, and present a concept for the codetermination of viral replication efficiency through these kinase activities: (i) cyclin H expression, in various human cell types, is substantially upregulated by strains of HCMV including the clinically relevant HCMV Merlin; (ii) vCDK/pUL97 interacts with human cyclin H in both HCMV-infected and plasmid-transfected cell systems; (iii) a doxycycline-inducible shRNA-dependent knock-down (KD) of cyclin H significantly reduces pUL97 activity (qSox in vitro kinase assay); (iv) accordingly, pUL97 in vitro kinase activity is seen significantly increased upon addition of recombinant cyclin H; (v) as a point of specific importance, human CDK7 activity shows an increase by vCDK/pUL97-mediated trans-stimulation (whereas pUL97 is not stimulated by CDK7); (vi) phosphosite-specific antibodies indicate an upregulated CDK7 phosphorylation upon HCMV infection, as mediated through a pUL97-specific modulatory effect (i.e. shown by pUL97 inhibitor treatment or pUL97-deficient viral mutant); (vii) finally, an efficient KD of cyclin H in primary fibroblasts generally results in an impaired HCMV replication efficiency as measured on protein and genomic levels. These results show evidence for the codetermination of viral replication by vCDK/pUL97, cyclin H and CDK7, thus supporting the specific importance of cyclin H as a central regulatory factor, and suggesting novel targeting options for antiviral drugs.
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Affiliation(s)
- Martin Schütz
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany.
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | - Mona Sommerer
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | - Melanie Kögler
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany
| | | | | | - Bert Klebl
- Lead Discovery Center GmbH, Dortmund, Germany
| | - Zin Naing
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Ece Egilmezer
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Stuart T Hamilton
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - William D Rawlinson
- Serology and Virology Division, NSW Health Pathology Microbiology, Prince of Wales Hospital, and Schools of Women's and Children's Health, Medicine and Biotechnology and Biomolecular Sciences, University of New South Wales, High Street, Sydney, Australia
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, FAU, Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, Erlangen 91054, Germany.
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Zeng J, Cao D, Yang S, Jaijyan DK, Liu X, Wu S, Cruz-Cosme R, Tang Q, Zhu H. Insights into the Transcriptome of Human Cytomegalovirus: A Comprehensive Review. Viruses 2023; 15:1703. [PMID: 37632045 PMCID: PMC10458407 DOI: 10.3390/v15081703] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a widespread pathogen that poses significant risks to immunocompromised individuals. Its genome spans over 230 kbp and potentially encodes over 200 open-reading frames. The HCMV transcriptome consists of various types of RNAs, including messenger RNAs (mRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs), with emerging insights into their biological functions. HCMV mRNAs are involved in crucial viral processes, such as viral replication, transcription, and translation regulation, as well as immune modulation and other effects on host cells. Additionally, four lncRNAs (RNA1.2, RNA2.7, RNA4.9, and RNA5.0) have been identified in HCMV, which play important roles in lytic replication like bypassing acute antiviral responses, promoting cell movement and viral spread, and maintaining HCMV latency. CircRNAs have gained attention for their important and diverse biological functions, including association with different diseases, acting as microRNA sponges, regulating parental gene expression, and serving as translation templates. Remarkably, HCMV encodes miRNAs which play critical roles in silencing human genes and other functions. This review gives an overview of human cytomegalovirus and current research on the HCMV transcriptome during lytic and latent infection.
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Affiliation(s)
- Janine Zeng
- Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ 070101, USA
| | - Di Cao
- Department of Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen 518052, China
| | - Shaomin Yang
- Department of Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen 518052, China
| | - Dabbu Kumar Jaijyan
- Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ 070101, USA
| | - Xiaolian Liu
- Institute of Pathogenic Organisms, Shenzhen Center for Disease Control and Prevention, Shenzhen 518055, China
| | - Songbin Wu
- Department of Pain Medicine, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen 518052, China
| | - Ruth Cruz-Cosme
- Department of Microbiology, Howard University College of Medicine, 520 W Street NW, Washington, DC 20059, USA
| | - Qiyi Tang
- Department of Microbiology, Howard University College of Medicine, 520 W Street NW, Washington, DC 20059, USA
| | - Hua Zhu
- Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ 070101, USA
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Iwahori S, Umaña AC, Kalejta RF, Murata T. Serine 13 of the human cytomegalovirus viral cyclin-dependent kinase UL97 is required for regulatory protein 14-3-3 binding and UL97 stability. J Biol Chem 2022; 298:102513. [PMID: 36150501 PMCID: PMC9587022 DOI: 10.1016/j.jbc.2022.102513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 09/08/2022] [Accepted: 09/13/2022] [Indexed: 11/14/2022] Open
Abstract
The human cytomegalovirus (HCMV) UL97 protein is a conserved herpesvirus protein kinase (CHPK) and a viral cyclin-dependent kinase (v-CDK). However, mechanisms regulating its activity in the context of infection are unknown. Here, we identified several cellular regulatory 14-3-3 proteins as UL97-interacting partners that promote UL97 stability. Humans are known to encode seven isoforms of 14-3-3 proteins (β, ε, η, γ, σ, θ, and ζ) that bind phosphoserines or phosphothreonines to impact protein structure, stability, activity, and localization. Our proteomic analysis of UL97 identified 49 interacting partners, including 14-3-3 isoforms β, η, and γ. Furthermore, coimmunoprecipitation with Western blotting assays demonstrated that UL97 interaction with 14-3-3 isoforms β, ε, η, γ, and θ occurs in a kinase activity-dependent manner. Using mutational analysis, we determined the serine residue at amino acid 13 of UL97 is crucial for 14-3-3 interaction. We demonstrate UL97 S13A (serine to alanine substitution at residue 13) retains kinase activity but the mutant protein accumulated at lower levels than WT UL97. Finally, we show both laboratory (AD169) and clinical (TB40/E) strains of HCMV encoding UL97 S13A replicated with WT kinetics in fibroblasts but showed decreased UL97 accumulation. Taken together, we conclude that 14-3-3 proteins interact with and stabilize UL97 during HCMV infection.
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Affiliation(s)
- Satoko Iwahori
- Department of Virology and Parasitology, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan; Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI, USA
| | - Angie C Umaña
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI, USA
| | - Robert F Kalejta
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI, USA.
| | - Takayuki Murata
- Department of Virology and Parasitology, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan.
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Functional Relevance of the Interaction between Human Cyclins and the Cytomegalovirus-Encoded CDK-Like Protein Kinase pUL97. Viruses 2021; 13:v13071248. [PMID: 34198986 PMCID: PMC8310212 DOI: 10.3390/v13071248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 02/07/2023] Open
Abstract
The replication of human cytomegalovirus (HCMV) is characterized by a complex network of virus–host interaction. This involves the regulatory viral protein kinase pUL97, which represents a viral cyclin-dependent kinase ortholog (vCDK) combining typical structural and functional features of host CDKs. Notably, pUL97 interacts with the three human cyclin types T1, H and B1, whereby the binding region of cyclin T1 and the region conferring oligomerization of pUL97 were both assigned to amino acids 231–280. Here, we addressed the question of whether recombinant HCMVs harboring deletions in this region were impaired in cyclin interaction, kinase functionality or viral replication. To this end, recombinant HCMVs were generated by traceless BACmid mutagenesis and were phenotypically characterized using a methodological platform based on qPCR, coimmunoprecipitation, in vitro kinase assay (IVKA), Phos-tag Western blot and confocal imaging analysis. Combined data illustrate the following: (i) infection kinetics of all three recombinant HCMVs, i.e., ORF-UL97 ∆231–255, ∆256–280 and ∆231–280, showed impaired replication efficiency compared to the wild type, amongst which the largest deletion exhibited the most pronounced defect; (ii) specifically, this mutant ∆231–280 showed a loss of interaction with cyclin T1, as demonstrated by CoIP and confocal imaging; (iii) IVKA and Phos-tag analyses revealed strongly affected kinase activity for ∆231–280, with strong impairment of both autophosphorylation and substrate phosphorylation, but less pronounced impairments for ∆231–255 and ∆256–280; and (iv) a bioinformatic assessment of the pUL97–cyclin T1 complex led to the refinement of our current binding model. Thus, the results provide initial evidence for the functional importance of the pUL97–cyclin interaction concerning kinase activity and viral replication fitness.
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Marschall M, Strojan H, Kiener R, Wangen C, Sonntag E, Müller R, Zeitträger I, Wagner S, Stamminger T, Milbradt J, Behrends U, Körber N, Bauer T, Schrödel S, Thirion C, Wagner R, Hutterer C. Differential upregulation of host cell protein kinases by the replication of α-, β- and γ-herpesviruses provides a signature of virus-specific signalling. J Gen Virol 2020; 101:284-289. [PMID: 31958050 DOI: 10.1099/jgv.0.001370] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Infections with human herpesviruses share several molecular characteristics, but the diversified medical outcomes are distinct to viral subfamilies and species. Notably, both clinical and molecular correlates of infection are a challenging field and distinct patterns of virus-host interaction have rarely been defined; this study therefore focuses on the search for virus-specific molecular indicators. As previous studies have demonstrated the impact of herpesvirus infections on changes in host signalling pathways, we illustrate virus-modulated expression levels of individual cellular protein kinases. Current data reveal (i) α-, β- and γ-herpesvirus-specific patterns of kinase modulation as well as (ii) differential levels of up-/downregulated kinase expression and phosphorylation, which collectively suggest (iii) defined signalling patterns specific for the various viruses (VSS) that may prove useful for defining molecular indicators. Combined, the study confirms the correlation between herpesviral replication and modulation of signalling kinases, possibly exploitable for the in vitro characterization of viral infections.
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Affiliation(s)
- Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Hanife Strojan
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Richard Kiener
- Institute for Microbiology and Hygiene, University of Regensburg, Regensburg, Germany
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Eric Sonntag
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Regina Müller
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Isabel Zeitträger
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | | | - Jens Milbradt
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Uta Behrends
- German Center for Infection Research (DZIF), Munich, Germany
- Research Unit Gene Vectors, Helmholtz Zentrum München/TUM, Munich, Germany
- Children's Hospital Schwabing, Technische Universität München (TUM), Munich, Germany
| | - Nina Körber
- Institute of Virology, Helmholtz Zentrum München/TUM, Munich, Germany
| | - Tanja Bauer
- Institute of Virology, Helmholtz Zentrum München/TUM, Munich, Germany
- German Center for Infection Research (DZIF), Munich, Germany
| | | | | | - Ralf Wagner
- Institute for Microbiology and Hygiene, University of Regensburg, Regensburg, Germany
| | - Corina Hutterer
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
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The Cytomegalovirus Protein Kinase pUL97:Host Interactions, Regulatory Mechanisms and Antiviral Drug Targeting. Microorganisms 2020; 8:microorganisms8040515. [PMID: 32260430 PMCID: PMC7232230 DOI: 10.3390/microorganisms8040515] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/02/2020] [Accepted: 04/02/2020] [Indexed: 12/25/2022] Open
Abstract
Human cytomegalovirus (HCMV) expresses a variety of viral regulatory proteins that undergo close interaction with host factors including viral-cellular multiprotein complexes. The HCMV protein kinase pUL97 represents a viral cyclin-dependent kinase ortholog (vCDK) that determines the efficiency of HCMV replication via phosphorylation of viral and cellular substrates. A hierarchy of functional importance of individual pUL97-mediated phosphorylation events has been discussed; however, the most pronounced pUL97-dependent phenotype could be assigned to viral nuclear egress, as illustrated by deletion of the UL97 gene or pharmacological pUL97 inhibition. Despite earlier data pointing to a cyclin-independent functionality, experimental evidence increasingly emphasized the role of pUL97-cyclin complexes. Consequently, the knowledge about pUL97 involvement in host interaction, viral nuclear egress and additional replicative steps led to the postulation of pUL97 as an antiviral target. Indeed, validation experiments in vitro and in vivo confirmed the sustainability of this approach. Consequently, current investigations of pUL97 in antiviral treatment go beyond the known pUL97-mediated ganciclovir prodrug activation and henceforward include pUL97-specific kinase inhibitors. Among a number of interesting small molecules analyzed in experimental and preclinical stages, maribavir is presently investigated in clinical studies and, in the near future, might represent a first kinase inhibitor applied in the field of antiviral therapy.
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Cazorla-Vázquez S, Steingruber M, Marschall M, Engel FB. Human cytomegaloviral multifunctional protein kinase pUL97 impairs zebrafish embryonic development and increases mortality. Sci Rep 2019; 9:7219. [PMID: 31076608 PMCID: PMC6510723 DOI: 10.1038/s41598-019-43649-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 04/26/2019] [Indexed: 12/27/2022] Open
Abstract
Cytomegalovirus is a worldwide-distributed human pathogen, which is the leading cause of congenital virus infection, affecting 0.5 to 2% of live births. To date, it is largely unclear which molecular mechanisms underlie the symptomatic outcomes. This is mainly due to species specificity and limited homology among cytomegalovirus genomes. As it is not possible to infect model organisms with human cytomegalovirus, the aim of this study was to develop a heterologous system allowing in the future the elucidation of the pathological role of individual viral proteins. As a model organism the zebrafish has been chosen due to its ease of manipulation and characterization as well as its large offspring. As cytomegalovirus model protein, pUL97 was characterized because it is multiply involved in virus-host interaction. Here, we show in zebrafish embryos, that (i) pUL97 can be expressed in zebrafish, (ii) increasing pUL97 expression levels quantitatively correlate with both minor and major pathological defects, (iii) pUL97 expression impairs cell cycle progression and induces cell death, (iv) active pUL97, but not an inactive mutant, induces excess mortality, and (v) co-administration of a pUL97 inhibitor reduces embryonic pathology. Collectively, these data indicate the suitability of zebrafish to elucidate the pathological role of human cytomegaloviral proteins.
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Affiliation(s)
- Salvador Cazorla-Vázquez
- Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 12, 91052, Erlangen, Germany
| | - Mirjam Steingruber
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054, Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 4, 91054, Erlangen, Germany
| | - Felix B Engel
- Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schwabachanlage 12, 91052, Erlangen, Germany.
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Steingruber M, Keller L, Socher E, Ferre S, Hesse AM, Couté Y, Hahn F, Büscher N, Plachter B, Sticht H, Marschall M. Cyclins B1, T1, and H differ in their molecular mode of interaction with cytomegalovirus protein kinase pUL97. J Biol Chem 2019; 294:6188-6203. [PMID: 30782840 DOI: 10.1074/jbc.ra118.007049] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 02/08/2019] [Indexed: 12/19/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a common β-herpesvirus causing life-long latent infections. HCMV replication interferes with cell cycle regulation in host cells because the HCMV-encoded cyclin-dependent kinase (CDK) ortholog pUL97 extensively phosphorylates the checkpoint regulator retinoblastoma protein. pUL97 also interacts with cyclins B1, T1, and H, and recent findings have strongly suggested that these interactions influence pUL97 substrate recognition. Interestingly, here we detected profound mechanistic differences among these pUL97-cyclin interactions. Our study revealed the following. (i) pUL97 interacts with cyclins B1 and H in a manner dependent on pUL97 activity and HCMV-specific cyclin modulation, respectively. (ii) The phosphorylated state of both proteins is an important determinant of the pUL97-cyclin B1 interaction. (iii) Activated phospho-Thr-315 cyclin H is up-regulated during HCMV replication. (iv) Thr-315 phosphorylation is independent of intracellular pUL97 or CDK7 activity. (v) pUL97-mediated in vitro phosphorylation is detectable for cyclin B1 but not H. (vi) Mutual transphosphorylation between pUL97 and CDK7 is not detectable, and an MS-based phosphosite analysis indicated that pUL97 might unexpectedly not be phosphorylated in its T-loop. (vii) The binary complexes pUL97-cyclin H and CDK7-cyclin H as well as the ternary complex pUL97-cyclin-H-CDK7 are detectable in an assembly-based CoIP approach. (viii) pUL97 self-interaction can be bridged by the transcriptional cyclins T1 or H but not by the classical cell cycle-regulating B1 cyclin. Combined, our findings unravel a number of cyclin type-specific differences in pUL97 interactions and suggest a multifaceted regulatory impact of cyclins on HCMV replication.
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Affiliation(s)
- Mirjam Steingruber
- From the Institute for Clinical and Molecular Virology, 91054 Erlangen, Germany.
| | - Lena Keller
- From the Institute for Clinical and Molecular Virology, 91054 Erlangen, Germany
| | - Eileen Socher
- Division of Bioinformatics, Institute of Biochemistry Friedrich-Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Sabrina Ferre
- the Université Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France
| | - Anne-Marie Hesse
- the Université Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France
| | - Yohann Couté
- the Université Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France
| | - Friedrich Hahn
- From the Institute for Clinical and Molecular Virology, 91054 Erlangen, Germany
| | - Nicole Büscher
- the Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany
| | - Bodo Plachter
- the Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, 55131 Mainz, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry Friedrich-Alexander University of Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Manfred Marschall
- From the Institute for Clinical and Molecular Virology, 91054 Erlangen, Germany.
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König P, Büscher N, Steingruber M, Socher E, Sticht H, Tenzer S, Plachter B, Marschall M. Dynamic regulatory interaction between cytomegalovirus major tegument protein pp65 and protein kinase pUL97 in intracellular compartments, dense bodies and virions. J Gen Virol 2017; 98:2850-2863. [PMID: 29022869 DOI: 10.1099/jgv.0.000939] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous pathogen of considerable clinical importance. Understanding the processes that are important for viral replication is essential for the development of therapeutic strategies against HCMV infection. The HCMV-encoded protein kinase pUL97 is an important multifunctional regulator of viral replication. Several viral and cellular proteins are phosphorylated by pUL97. The phosphoprotein pp65 is one important substrate of pUL97. It is the most abundant tegument protein of HCMV virions, mediating the upload of other virion constituents and contributing to particle integrity. Further to that, it interferes with host innate immune defences, thereby enabling efficient viral replication. By applying different approaches, we characterized the pp65-pUL97 interaction in various compartments. Specifically, the pUL97 interaction domain of pp65 was defined (282-415). A putative cyclin bridge that enhances pUL97-pp65 interaction was identified. The impact of pUL97 mutation on virion and dense body morphogenesis was addressed using pUL97 mutant viruses. Alterations in the proteome of viral particles were seen, especially with mutant viruses expressing cytoplasmic variants of pUL97. On the basis of these data we postulate a so far poorly recognized functional relationship between pp65 and pUL97, and present a refined model of pp65-pUL97 interaction.
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Affiliation(s)
- Patrick König
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Nicole Büscher
- Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Mirjam Steingruber
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Eileen Socher
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Stefan Tenzer
- Institute for Immunology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Bodo Plachter
- Research Center for Immunotherapy (FZI), University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany.,Institute for Virology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
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Proteomic Interaction Patterns between Human Cyclins, the Cyclin-Dependent Kinase Ortholog pUL97 and Additional Cytomegalovirus Proteins. Viruses 2016; 8:v8080219. [PMID: 27548200 PMCID: PMC4997581 DOI: 10.3390/v8080219] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/25/2016] [Accepted: 08/02/2016] [Indexed: 01/13/2023] Open
Abstract
The human cytomegalovirus (HCMV)-encoded cyclin-dependent kinase (CDK) ortholog pUL97 associates with human cyclin B1 and other types of cyclins. Here, the question was addressed whether cyclin interaction of pUL97 and additional viral proteins is detectable by mass spectrometry-based approaches. Proteomic data were validated by coimmunoprecipitation (CoIP), Western blot, in vitro kinase and bioinformatic analyses. Our findings suggest that: (i) pUL97 shows differential affinities to human cyclins; (ii) pUL97 inhibitor maribavir (MBV) disrupts the interaction with cyclin B1, but not with other cyclin types; (iii) cyclin H is identified as a new high-affinity interactor of pUL97 in HCMV-infected cells; (iv) even more viral phosphoproteins, including all known substrates of pUL97, are detectable in the cyclin-associated complexes; and (v) a first functional validation of pUL97-cyclin B1 interaction, analyzed by in vitro kinase assay, points to a cyclin-mediated modulation of pUL97 substrate preference. In addition, our bioinformatic analyses suggest individual, cyclin-specific binding interfaces for pUL97-cyclin interaction, which could explain the different strengths of interactions and the selective inhibitory effect of MBV on pUL97-cyclin B1 interaction. Combined, the detection of cyclin-associated proteins in HCMV-infected cells suggests a complex pattern of substrate phosphorylation and a role of cyclins in the fine-modulation of pUL97 activities.
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12
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Zaborowska J, Isa NF, Murphy S. P-TEFb goes viral. Bioessays 2016; 38 Suppl 1:S75-85. [DOI: 10.1002/bies.201670912] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/23/2015] [Accepted: 09/26/2015] [Indexed: 01/31/2023]
Affiliation(s)
| | - Nur F. Isa
- Sir William Dunn School of Pathology; University of Oxford; Oxford UK
- Department of Biotechnology; Kulliyyah of Science, IIUM; Kuantan Pahang Malaysia
| | - Shona Murphy
- Sir William Dunn School of Pathology; University of Oxford; Oxford UK
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13
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Sonntag E, Hamilton ST, Bahsi H, Wagner S, Jonjic S, Rawlinson WD, Marschall M, Milbradt J. Cytomegalovirus pUL50 is the multi-interacting determinant of the core nuclear egress complex (NEC) that recruits cellular accessory NEC components. J Gen Virol 2016; 97:1676-1685. [PMID: 27145986 DOI: 10.1099/jgv.0.000495] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Nuclear egress of herpesvirus capsids through the nuclear envelope is mediated by the multimeric nuclear egress complex (NEC). The human cytomegalovirus (HCMV) core NEC is defined by an interaction between the membrane-anchored pUL50 and its nuclear co-factor pUL53, tightly associated through heterodimeric corecruitment to the nuclear envelope. Cellular proteins, such as p32/gC1qR, emerin and protein kinase C (PKC), are recruited by direct interaction with pUL50 for the multimeric extension of the NEC. As a functionally important event, the recruitment of both viral and cellular protein kinases leads to site-specific lamin phosphorylation and nuclear lamina disassembly. In this study, interaction domains within pUL50 for its binding partners were defined by co-immunoprecipitation. The interaction domain for pUL53 is located within the pUL50 N-terminus (residues 10-169), interaction domains for p32/gC1qR (100-358) and PKC (100-280) overlap in the central part of pUL50, and the interaction domain for emerin is located in the C-terminus (265-397). Moreover, expression and formation of core NEC proteins at the nuclear rim were consistently detected in cells permissive for productive HCMV replication, including two trophoblast-cell lines. Importantly, regular nuclear-rim formation of the core NEC was blocked by inhibition of cyclin-dependent kinase (CDK) activity. In relation to the recently published crystal structure of the HCMV core NEC, our findings result in a refined view of NEC assembly. In particular, we suggest that CDKs may play an important regulatory role in NEC formation during HCMV replication.
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Affiliation(s)
- Eric Sonntag
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Stuart T Hamilton
- Virology Division, SEALS Microbiology, Prince of Wales Hospital, Sydney, Australia
| | - Hanife Bahsi
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Stipan Jonjic
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - William D Rawlinson
- Virology Division, SEALS Microbiology, Prince of Wales Hospital, Sydney, Australia
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Jens Milbradt
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
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14
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Dinkel H, Van Roey K, Michael S, Kumar M, Uyar B, Altenberg B, Milchevskaya V, Schneider M, Kühn H, Behrendt A, Dahl SL, Damerell V, Diebel S, Kalman S, Klein S, Knudsen AC, Mäder C, Merrill S, Staudt A, Thiel V, Welti L, Davey NE, Diella F, Gibson TJ. ELM 2016--data update and new functionality of the eukaryotic linear motif resource. Nucleic Acids Res 2016; 44:D294-300. [PMID: 26615199 PMCID: PMC4702912 DOI: 10.1093/nar/gkv1291] [Citation(s) in RCA: 224] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 11/04/2015] [Accepted: 11/05/2015] [Indexed: 01/18/2023] Open
Abstract
The Eukaryotic Linear Motif (ELM) resource (http://elm.eu.org) is a manually curated database of short linear motifs (SLiMs). In this update, we present the latest additions to this resource, along with more improvements to the web interface. ELM 2016 contains more than 240 different motif classes with over 2700 experimentally validated instances, manually curated from more than 2400 scientific publications. In addition, more data have been made available as individually searchable pages and are downloadable in various formats.
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Affiliation(s)
- Holger Dinkel
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Kim Van Roey
- Health Services Research Unit, Operational Direction Public Health and Surveillance, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium
| | - Sushama Michael
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Manjeet Kumar
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Bora Uyar
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Brigitte Altenberg
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Vladislava Milchevskaya
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | | | - Helen Kühn
- Ruprecht-Karls-Universität, Heidelberg, Germany
| | | | | | | | | | - Sara Kalman
- Ruprecht-Karls-Universität, Heidelberg, Germany
| | | | | | | | | | | | - Vera Thiel
- Ruprecht-Karls-Universität, Heidelberg, Germany
| | - Lukas Welti
- Ruprecht-Karls-Universität, Heidelberg, Germany
| | - Norman E Davey
- Conway Institute of Biomolecular and Biomedical Sciences, University College Dublin, Dublin 4, Ireland
| | - Francesca Diella
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Toby J Gibson
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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15
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Zaborowska J, Isa NF, Murphy S. P-TEFb goes viral. ACTA ACUST UNITED AC 2015; 1:106-116. [PMID: 27398404 PMCID: PMC4863834 DOI: 10.1002/icl3.1037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/23/2015] [Accepted: 09/26/2015] [Indexed: 01/30/2023]
Abstract
Positive transcription elongation factor b (P‐TEFb), which comprises cyclin‐dependent kinase 9 (CDK9) kinase and cyclin T subunits, is an essential kinase complex in human cells. Phosphorylation of the negative elongation factors by P‐TEFb is required for productive elongation of transcription of protein‐coding genes by RNA polymerase II (pol II). In addition, P‐TEFb‐mediated phosphorylation of the carboxyl‐terminal domain (CTD) of the largest subunit of pol II mediates the recruitment of transcription and RNA processing factors during the transcription cycle. CDK9 also phosphorylates p53, a tumor suppressor that plays a central role in cellular responses to a range of stress factors. Many viral factors affect transcription by recruiting or modulating the activity of CDK9. In this review, we will focus on how the function of CDK9 is regulated by viral gene products. The central role of CDK9 in viral life cycles suggests that drugs targeting the interaction between viral products and P‐TEFb could be effective anti‐viral agents.
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Affiliation(s)
| | - Nur F Isa
- Sir William Dunn School of Pathology University of Oxford Oxford UK; Department of Biotechnology Kulliyyah of Science, IIUM Kuantan Pahang Malaysia
| | - Shona Murphy
- Sir William Dunn School of Pathology University of Oxford Oxford UK
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16
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Graf L, Feichtinger S, Naing Z, Hutterer C, Milbradt J, Webel R, Wagner S, Scott GM, Hamilton ST, Rawlinson WD, Stamminger T, Thomas M, Marschall M. New insight into the phosphorylation-regulated intranuclear localization of human cytomegalovirus pUL69 mediated by cyclin-dependent kinases (CDKs) and viral CDK orthologue pUL97. J Gen Virol 2015; 97:144-151. [PMID: 26555090 DOI: 10.1099/jgv.0.000337] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cyclin-dependent kinases (CDKs) are multifaceted regulators involved in the replication of human cytomegalovirus. Recently, we demonstrated an interaction of CDK9-cyclin T1 as well as viral CDK orthologue pUL97 with the viral regulator pUL69, thereby leading to pUL69-activating phosphorylation. Here, we demonstrate that colocalization and direct pUL69-cyclin T1 interaction is independent of viral strains and host cell types. In vitro phosphorylation of pUL69 by CDK9 or pUL97 did not occur in a single site-specific manner, but at multiple sites. The previously described fine-speckled nuclear aggregation of pUL69 was assigned to the late phase of viral replication. CDK inhibitors, including a novel inhibitor of the CDK-activating kinase CDK7, massively intensified this fine-speckled accumulation. Interestingly, we also observed spontaneous pUL69 accumulation in the absence of inhibitors at a lower frequency. These findings provide new insight into pUL69 kinase interregulation and emphasize the importance of pUL69 phosphorylation for correct intranuclear localization.
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Affiliation(s)
- Laura Graf
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Sabine Feichtinger
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Zin Naing
- Virology Division, SEALS Microbiology, Prince of Wales Hospital, University of New South Wales, Sydney, Australia
| | - Corina Hutterer
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Jens Milbradt
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Rike Webel
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Sabrina Wagner
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Gillian M Scott
- Virology Division, SEALS Microbiology, Prince of Wales Hospital, University of New South Wales, Sydney, Australia
| | - Stuart T Hamilton
- Virology Division, SEALS Microbiology, Prince of Wales Hospital, University of New South Wales, Sydney, Australia
| | - William D Rawlinson
- Virology Division, SEALS Microbiology, Prince of Wales Hospital, University of New South Wales, Sydney, Australia
| | - Thomas Stamminger
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Marco Thomas
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg, Erlangen, Germany
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17
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Rahbar A, Cederarv M, Wolmer-Solberg N, Tammik C, Stragliotto G, Peredo I, Fornara O, Xu X, Dzabic M, Taher C, Skarman P, Söderberg-Nauclér C. Enhanced neutrophil activity is associated with shorter time to tumor progression in glioblastoma patients. Oncoimmunology 2015; 5:e1075693. [PMID: 27057448 DOI: 10.1080/2162402x.2015.1075693] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/08/2015] [Accepted: 07/17/2015] [Indexed: 02/02/2023] Open
Abstract
Glioblastoma multiforme (GBM) is a highly malignant tumor with a poor outcome that is often positive for human cytomegalovirus (HCMV). GBM patients often have excessive numbers of neutrophils and macrophages near and within the tumor. Here, we characterized the cytokine patterns in the blood of GBM patients with and without Valganciclovir treatment. Furthermore, we determined whether neutrophil activation is related to HCMV status and patient outcome. Blood samples for analyses of cytokines and growth factors were collected from 42 GBM patients at the time of diagnosis (n = 42) and at weeks 12 and 24 after surgery. Blood neutrophils of 28 GBM patients were examined for CD11b expression. The levels of pro- and anti-inflammatory cytokines and chemokines-including interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, IL-12p70, IL-17A, transforming growth factor (TGF)-β1, interferon-γ, interferon-α, tumor necrosis factor α, and monocyte chemoattractant protein (MCP)-1were analyzed with a bead-based flow cytometry assay. During the first six months after surgery, neutrophil activity was increased in 12 patients and was unchanged or decreased in 16. Patients with increased neutrophil activity had enhanced IL-12p70, high grade HCMV and a shorter time to tumor progression (TTP) than patients without or decreased neutrophil activity (median TTP; 5.4 vs. 12 months, 95% confidence interval; 1.6-10 vs. 0.1-0.6, hazard ratio = 3 vs. 0.4, p = 0.004). The levels of IL-12p70 were significantly decreased in Valganciclovir treated patients (n = 22, T 12W vs. T 24W, p = 0.03). In conclusion, our findings suggest that neutrophil activation is an early sign of tumor progression in GBM patients.
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Affiliation(s)
- Afsar Rahbar
- Department of Medicine Solna, Microbial Pathogenesis Research Unit, Center for Molecular Medicine, Karolinska Institute , Stockholm, Sweden
| | - Madeleine Cederarv
- Department of Medicine Solna, Microbial Pathogenesis Research Unit, Center for Molecular Medicine, Karolinska Institute , Stockholm, Sweden
| | - Nina Wolmer-Solberg
- Department of Medicine Solna, Microbial Pathogenesis Research Unit, Center for Molecular Medicine, Karolinska Institute , Stockholm, Sweden
| | - Charlotte Tammik
- Department of Medicine Solna, Microbial Pathogenesis Research Unit, Center for Molecular Medicine, Karolinska Institute , Stockholm, Sweden
| | - Giuseppe Stragliotto
- Department of Neurology, Karolinska University Hospital, Stockholm, Sweden; Department of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden
| | - Inti Peredo
- Department of Neurology, Karolinska University Hospital, Stockholm, Sweden; Department of Neurosurgery, Karolinska University Hospital, Stockholm, Sweden
| | - Olesja Fornara
- Department of Medicine Solna, Microbial Pathogenesis Research Unit, Center for Molecular Medicine, Karolinska Institute , Stockholm, Sweden
| | - Xinling Xu
- Department of Medicine Solna, Microbial Pathogenesis Research Unit, Center for Molecular Medicine, Karolinska Institute , Stockholm, Sweden
| | - Mensur Dzabic
- Department of Medicine Solna, Microbial Pathogenesis Research Unit, Center for Molecular Medicine, Karolinska Institute , Stockholm, Sweden
| | - Chato Taher
- Department of Medicine Solna, Microbial Pathogenesis Research Unit, Center for Molecular Medicine, Karolinska Institute , Stockholm, Sweden
| | - Petra Skarman
- Department of Medicine Solna, Microbial Pathogenesis Research Unit, Center for Molecular Medicine, Karolinska Institute , Stockholm, Sweden
| | - Cecilia Söderberg-Nauclér
- Department of Medicine Solna, Microbial Pathogenesis Research Unit, Center for Molecular Medicine, Karolinska Institute , Stockholm, Sweden
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18
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The Interaction between Cyclin B1 and Cytomegalovirus Protein Kinase pUL97 is Determined by an Active Kinase Domain. Viruses 2015; 7:4582-601. [PMID: 26270673 PMCID: PMC4576195 DOI: 10.3390/v7082834] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 07/12/2015] [Accepted: 07/27/2015] [Indexed: 02/06/2023] Open
Abstract
Replication of human cytomegalovirus (HCMV) is characterized by a tight virus-host cell interaction. Cyclin-dependent protein kinases (CDKs) are functionally integrated into viral gene expression and protein modification. The HCMV-encoded protein kinase pUL97 acts as a CDK ortholog showing structural and functional similarities. Recently, we reported an interaction between pUL97 kinase with a subset of host cyclins, in particular with cyclin T1. Here, we describe an interaction of pUL97 at an even higher affinity with cyclin B1. As a striking feature, the interaction between pUL97 and cyclin B1 proved to be strictly dependent on pUL97 activity, as interaction could be abrogated by treatment with pUL97 inhibitors or by inserting mutations into the conserved kinase domain or the nonconserved C-terminus of pUL97, both producing loss of activity. Thus, we postulate that the mechanism of pUL97-cyclin B1 interaction is determined by an active pUL97 kinase domain.
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19
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Hamilton ST, Milbradt J, Marschall M, Rawlinson WD. Human cytomegalovirus replication is strictly inhibited by siRNAs targeting UL54, UL97 or UL122/123 gene transcripts. PLoS One 2014; 9:e97231. [PMID: 24887060 PMCID: PMC4041654 DOI: 10.1371/journal.pone.0097231] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 04/16/2014] [Indexed: 01/16/2023] Open
Abstract
Human cytomegalovirus (HCMV) causes severe sequelae in immunocompromised hosts. Current antiviral therapies have serious adverse effects, with treatment in many clinical settings problematic, making new therapeutic approaches necessary. We examined the in vitro efficacy of small interfering RNAs (siRNAs) targeting the HCMV gene transcripts UL54 (DNA polymerase), UL97 (protein kinase) and UL122/123 (immediate-early proteins) as inhibitors of viral protein expression and virus replication in cell cultures. Two siRNAs for each HCMV target (designated A and B) were assessed for inhibition efficacy using western blot and standard plaque assays. Continuous human embryonic kidney 293T cells were treated with HCMV or non-specific scrambled (siSc) siRNA followed by transfection with plasmids expressing the target transcripts. Human MRC-5 fibroblasts were HCMV-siRNA or siSc treated, infected with HCMV strain AD169 (1 pfu/cell) and HCMV immediate-early (IE1p72 and IE2p86), early (pp65), early-late (pUL97) and true late (MCP) protein and virus progeny production measured during a single round of replication. Concordant results showed siUL54B, siUL97A and siUL122B displayed the most potent inhibitory effects with a reduction of 92.7%, 99.6% and 93.7% in plasmid protein expression, 65.9%, 58.1% and 64.8% in total HCMV protein expression and 97.2%, 96.2% and 94.3% (p<0.0001) in viral progeny production respectively. Analysing the siRNA inhibitory effects during multiple rounds of HCMV replication at a multiplicity of infection of 0.001 pfu/cell, siUL54B, siUL97A and siUL122B treatment resulted in a reduction of 80.0%, 59.6% and 84.5% in total HCMV protein expression, 52.9%, 49.2% and 58.3% in number of cells infected and 98.5%, 91.4% and 99.1% (p<0.0001) in viral progeny production at 7 dpi respectively. These results suggest potential in vivo siRNA therapies targeting the HCMV gene transcripts UL54, UL97 and UL122/123 would be highly effective, however, the antiviral efficacy of siRNAs targeting UL97 may be more highly dependent on viral load and methods of administration.
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Affiliation(s)
- Stuart T Hamilton
- Virology Division, SEALS Microbiology, Prince of Wales Hospital, Sydney, Australia; School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Jens Milbradt
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - William D Rawlinson
- Virology Division, SEALS Microbiology, Prince of Wales Hospital, Sydney, Australia; School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia; School of Medical Sciences, University of New South Wales, Sydney, Australia
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20
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Differential properties of cytomegalovirus pUL97 kinase isoforms affect viral replication and maribavir susceptibility. J Virol 2014; 88:4776-85. [PMID: 24522923 DOI: 10.1128/jvi.00192-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The human cytomegalovirus (HCMV)-encoded kinase pUL97 is required for efficient viral replication. Previous studies described two isoforms of pUL97, the full-length isoform (M1) and a smaller isoform likely resulting from translation initiation at codon 74 (M74). Here, we report the detection of a third pUL97 isoform during viral infection resulting from translation initiation at codon 157 (isoform M157). The consistent expression of isoform M157 as a minor component of pUL97 during infection with clinical and laboratory-adapted HCMV strains was suppressed when codon 157 was mutagenized. Viral mutants expressing specific isoforms were generated to compare their growth and drug susceptibility phenotypes, as well as pUL97 intracellular localization patterns and kinase activities. The exclusive expression of isoform M157 resulted in substantially reduced viral growth and resistance to the pUL97 inhibitor maribavir while retaining susceptibility to ganciclovir. Confocal imaging demonstrated reduced nuclear import of amino-terminal deletion isoforms compared to isoform M1. Isoform M157 showed reduced efficiency of various substrate protein interactions and autophosphorylation, whereas Rb phosphorylation was preserved. These results reveal differential properties of pUL97 isoforms that affect viral replication, with implications for the antiviral efficacy of maribavir. IMPORTANCE The HCMV UL97 kinase performs important functions in viral replication that are targeted by the antiviral drug maribavir. Here, we describe a naturally occurring short isoform of the kinase that when expressed by itself in a recombinant virus results in altered intracellular localization, impaired growth, and high-level resistance to maribavir compared to those of the predominant full-length counterpart. This is another factor to consider in explaining why maribavir appears to have variable antiviral activity in cell culture and in vivo.
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