1
|
Yan Y, Tang YD, Zheng C. When cyclin-dependent kinases meet viral infections, including SARS-CoV-2. J Med Virol 2022; 94:2962-2968. [PMID: 35288942 PMCID: PMC9088476 DOI: 10.1002/jmv.27719] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/18/2022] [Accepted: 02/25/2022] [Indexed: 11/16/2022]
Abstract
Cyclin‐dependent kinases (CDKs) are protein kinases that play a key role in cell division and transcriptional regulation. Recent studies have demonstrated the critical roles of CDKs in various viral infections. However, the molecular processes underpinning CDKs' roles in viral infection and host antiviral defense are unknown. This minireview briefly overviews CDKs' functions and highlights the most recent discoveries of CDKs' emerging roles during viral infections, thereby providing a scientific and theoretical foundation for antiviral regulation and shedding light on developing novel drug targets and therapeutic strategies against viral infection.
Collapse
Affiliation(s)
- Yan Yan
- Center of Clinical Laboratory, The Fifth People's Hospital of Wuxi, Affiliated Hospital of Jiangnan University, Wuxi, China
| | - Yan-Dong Tang
- Department of Immunology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.,State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Chunfu Zheng
- Department of Immunology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.,Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
2
|
Martinou EG, Moller-Levet CS, Angelidi AM. PBX4 functions as a potential novel oncopromoter in colorectal cancer: a comprehensive analysis of the PBX gene family. Am J Cancer Res 2022; 12:585-600. [PMID: 35261789 DOI: pmid/35261789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 01/10/2022] [Indexed: 02/05/2023] Open
Abstract
Pre-B-cell leukaemia (PBX) is a transcription factor family (PBX1, PBX2, PBX3 and PBX4) that regulates important cellular functions and has been identified to be involved in human cancers. This study aimed to explore the expression of PBX genes and their clinical significance in colorectal cancer (CRC). We analysed the differential expression of PBX genes in CRC vs. normal tissue, using the Cancer Genome Atlas (TCGA) (https://portal.gdc.cancer.gov/) and ONCOMINE platform (https://www.oncomine.org/). The UALCAN (http://ualcan.path.uab.edu/) interactive OMICS web-server was used to evaluate the epigenetic regulation of PBX genes via their promoter methylation status. We found that only PBX4 was upregulated whereas PBX1 and PBX3 were downregulated (644 tumour vs. 51 normal samples) (P<0.001). The methylation status of PBX4 promoter appeared to be decreased (P=1.4e-07) whereas the methylation status of PBX1 and PBX3 promoters was increased (P=3.8e-04 and P=3.2e-07, respectively) in cancer vs. normal samples. To determine the prognostic value of PBXs, we conducted a Kaplan-Meier survival analysis and multivariable COX regression. We observed that high PBX4 expression was associated with increased risk for a worse overall survival (OS) in the TCGA CRC patient cohort (n=639), (HR 1.46, 95% CI 1.14-1.88, P=0.003) adjusted for age, gender, tumour location and metastases. We conducted in vitro gene expression modulation experiments to investigate the impact of PBX4 overexpression in CRC cell (HCT116) growth. Additionally, we evaluated the RNA expression of epithelial-mesenchymal transition (EMT) and angiogenesis markers. In vitro studies showed that PBX4 overexpression increased CRC cell proliferation (P<0.001) and upregulated the expression of EMT markers VIM, CDH1, CDH2, ZEB1, SNAI1 (P<0.05) and angiomarker VEGFA (P<0.0001). Lastly, through the Cistrome data browser (http://dbtoolkit.cistrome.org/) we investigated putative transcriptional regulators and we performed gene set enrichment analysis in Enrichr server (https://maayanlab.cloud/Enrichr/) to identify related biological processes. Nineteen factors were identified to be putative regulators of PBX4 and gene set enrichment analysis showed that biological processes related to cell cycle and cell proliferation were enriched (GO:0051726: CDK8, JUN, JUND, and IRF1, P=0.001). In conclusion, our study identified PBX4 as a potential novel oncopromoter in CRC and its overexpression was found to be associated with increased risk for worse survival rate.
Collapse
Affiliation(s)
- Eirini G Martinou
- Hepatobiliary and Pancreatic Surgery Department, Royal Surrey County Hospital Guildford GU2 7XX, UK.,Faculty of Health and Medical Sciences, University of Surrey Guildford GU2 7XH, UK
| | - Carla S Moller-Levet
- Bioinformatics Department, Faculty of Health and Medical Sciences, University of Surrey Guildford GU2 7XH, UK
| | - Angeliki M Angelidi
- Department of Medicine, Beth Israel Deaconess Medical Centre, Harvard Medical School Boston, MA 02215, USA
| |
Collapse
|
3
|
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.
Collapse
|
4
|
Abstract
The question of whether human tumors express antigens that can be recognized by the immune system has been answered with a resounding YES. Most were identified through spontaneous antitumor humoral and cellular immune responses found in cancer patients and include peptides, glycopeptides, phosphopeptides, viral peptides, and peptides resulting from common mutations in oncogenes and tumor-suppressor genes, or common gene fusion events. Many have been extensively tested as candidates for anticancer vaccines. More recently, attention has been focused on the potentially large number of unique tumor antigens, mutated neoantigens, that are the predicted products of the numerous mutations revealed by exome sequencing of primary tumors. Only a few have been confirmed as targets of spontaneous immunity and immunosurveillance, and even fewer have been tested in preclinical and clinical settings. The field has been divided for a long time on the relative importance of shared versus mutated antigens in tumor surveillance and as candidates for vaccines. This question will eventually need to be answered in a head to head comparison in well-designed clinical trials. One advantage that shared antigens have over mutated antigens is their potential to be used in vaccines for primary cancer prevention. Cancer Immunol Res; 5(5); 347-54. ©2017 AACR.
Collapse
Affiliation(s)
- Olivera J Finn
- Department of Immunology, University of Pittsburgh School of Medicine and the University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania.
| |
Collapse
|
5
|
Sonntag E, Milbradt J, Svrlanska A, Strojan H, Häge S, Kraut A, Hesse AM, Amin B, Sonnewald U, Couté Y, Marschall M. Protein kinases responsible for the phosphorylation of the nuclear egress core complex of human cytomegalovirus. J Gen Virol 2017; 98:2569-2581. [PMID: 28949903 DOI: 10.1099/jgv.0.000931] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Nuclear egress of herpesvirus capsids is mediated by a multi-component nuclear egress complex (NEC) assembled by a heterodimer of two essential viral core egress proteins. In the case of human cytomegalovirus (HCMV), this core NEC is defined by the interaction between the membrane-anchored pUL50 and its nuclear cofactor, pUL53. NEC protein phosphorylation is considered to be an important regulatory step, so this study focused on the respective role of viral and cellular protein kinases. Multiply phosphorylated pUL50 varieties were detected by Western blot and Phos-tag analyses as resulting from both viral and cellular kinase activities. In vitro kinase analyses demonstrated that pUL50 is a substrate of both PKCα and CDK1, while pUL53 can also be moderately phosphorylated by CDK1. The use of kinase inhibitors further illustrated the importance of distinct kinases for core NEC phosphorylation. Importantly, mass spectrometry-based proteomic analyses identified five major and nine minor sites of pUL50 phosphorylation. The functional relevance of core NEC phosphorylation was confirmed by various experimental settings, including kinase knock-down/knock-out and confocal imaging, in which it was found that (i) HCMV core NEC proteins are not phosphorylated solely by viral pUL97, but also by cellular kinases; (ii) both PKC and CDK1 phosphorylation are detectable for pUL50; (iii) no impact of PKC phosphorylation on NEC functionality has been identified so far; (iv) nonetheless, CDK1-specific phosphorylation appears to be required for functional core NEC interaction. In summary, our findings provide the first evidence that the HCMV core NEC is phosphorylated by cellular kinases, and that the complex pattern of NEC phosphorylation has functional relevance.
Collapse
Affiliation(s)
- Eric Sonntag
- 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
| | - Adriana Svrlanska
- 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
| | - Sigrun Häge
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Alexandra Kraut
- Université Grenoble Alpes, CEA, INSERM, BIG-BGE, F-38000 Grenoble, France
| | - Anne-Marie Hesse
- Université Grenoble Alpes, CEA, INSERM, BIG-BGE, F-38000 Grenoble, France
| | - Bushra Amin
- Department of Biology, Institute for Biochemistry, FAU, Erlangen, Germany
- Present address: Department of Chemistry, University of Pittsburgh, Pittsburgh 15260, PA, USA
| | - Uwe Sonnewald
- Department of Biology, Institute for Biochemistry, FAU, Erlangen, Germany
| | - Yohann Couté
- Université Grenoble Alpes, CEA, INSERM, BIG-BGE, F-38000 Grenoble, France
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Erlangen, Germany
| |
Collapse
|
6
|
Strang BL. RO0504985 is an inhibitor of CMGC kinase proteins and has anti-human cytomegalovirus activity. Antiviral Res 2017; 144:21-26. [DOI: 10.1016/j.antiviral.2017.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 05/08/2017] [Indexed: 12/17/2022]
|
7
|
Hutterer C, Milbradt J, Hamilton S, Zaja M, Leban J, Henry C, Vitt D, Steingruber M, Sonntag E, Zeitträger I, Bahsi H, Stamminger T, Rawlinson W, Strobl S, Marschall M. Inhibitors of dual-specificity tyrosine phosphorylation-regulated kinases (DYRK) exert a strong anti-herpesviral activity. Antiviral Res 2017; 143:113-121. [PMID: 28400201 DOI: 10.1016/j.antiviral.2017.04.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/26/2017] [Accepted: 04/07/2017] [Indexed: 11/26/2022]
Abstract
Infection with human cytomegalovirus (HCMV) is a serious medical problem, particularly in immunocompromised individuals and neonates. The success of (val)ganciclovir therapy is hampered by low drug compatibility and induction of viral resistance. A novel strategy of antiviral treatment is based on the exploitation of cell-directed signaling, e. g. pathways with a known relevance for carcinogenesis and tumor drug development. Here we describe a principle for putative antiviral drugs based on targeting dual-specificity tyrosine phosphorylation-regulated kinases (DYRKs). DYRKs constitute an evolutionarily conserved family of protein kinases with key roles in the control of cell proliferation and differentiation. Members of the DYRK family are capable of phosphorylating a number of substrate proteins, including regulators of the cell cycle, e.g. DYRK1B can induce cell cycle arrest, a critical step for the regulation of HCMV replication. Here we provide first evidence for a critical role of DYRKs during viral replication and the high antiviral potential of DYRK inhibitors (SC84227, SC97202 and SC97208, Harmine and AZ-191). Using established replication assays for laboratory and clinically relevant strains of HCMV, concentration-dependent profiles of inhibition were obtained. Mean inhibitory concentrations (EC50) of 0.98 ± 0.08 μM/SC84227, 0.60 ± 0.02 μM/SC97202, 6.26 ± 1.64 μM/SC97208, 0.71 ± 0.019 μM/Harmine and 0.63 ± 0.23 μM/AZ-191 were determined with HCMV strain AD169-GFP for the infection of primary human fibroblasts. A first analysis of the mode of antiviral action suggested a block of viral replication at the early-late stage of HCMV gene expression. Moreover, rhesus macaque cytomegalovirus (RhCMV), varicella-zoster virus (VZV) and herpes simplex virus (HSV-1) showed a similarly high sensitivity to these compounds. Thus, we conclude that DYRK signaling represents a promising target pathway for the development of novel anti-herpesviral strategies.
Collapse
Affiliation(s)
- Corina Hutterer
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Germany.
| | - Jens Milbradt
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Germany
| | - Stuart Hamilton
- Serology and Virology Division, SEALS Microbiology Prince of Wales Hospital Randwick NSW 2013 and SOMS and BABS, University of NSW, Sydney, Australia
| | - Mirko Zaja
- 4SC Discovery GmbH, Martinsried, Germany
| | | | | | | | - Mirjam Steingruber
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Germany
| | - Eric Sonntag
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Germany
| | - Isabel Zeitträger
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Germany
| | - Hanife Bahsi
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Germany
| | - Thomas Stamminger
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Germany
| | - William Rawlinson
- Serology and Virology Division, SEALS Microbiology Prince of Wales Hospital Randwick NSW 2013 and SOMS and BABS, University of NSW, Sydney, Australia
| | | | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), Germany.
| |
Collapse
|
8
|
Arend KC, Lenarcic EM, Vincent HA, Rashid N, Lazear E, McDonald IM, Gilbert TSK, East MP, Herring LE, Johnson GL, Graves LM, Moorman NJ. Kinome Profiling Identifies Druggable Targets for Novel Human Cytomegalovirus (HCMV) Antivirals. Mol Cell Proteomics 2017; 16:S263-S276. [PMID: 28237943 PMCID: PMC5393402 DOI: 10.1074/mcp.m116.065375] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 02/23/2017] [Indexed: 11/06/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a significant cause of disease in immune-compromised adults and immune naïve newborns. No vaccine exists to prevent HCMV infection, and current antiviral therapies have toxic side effects that limit the duration and intensity of their use. There is thus an urgent need for new strategies to treat HCMV infection. Repurposing existing drugs as antivirals is an attractive approach to limit the time and cost of new antiviral drug development. Virus-induced changes in infected cells are often driven by changes in cellular kinase activity, which led us to hypothesize that defining the complement of kinases (the kinome), whose abundance or expression is altered during infection would identify existing kinase inhibitors that could be repurposed as new antivirals. To this end, we applied a kinase capture technique, multiplexed kinase inhibitor bead-mass spectrometry (MIB-MS) kinome, to quantitatively measure perturbations in >240 cellular kinases simultaneously in cells infected with a laboratory-adapted (AD169) or clinical (TB40E) HCMV strain. MIB-MS profiling identified time-dependent increases and decreases in MIB binding of multiple kinases including cell cycle kinases, receptor tyrosine kinases, and mitotic kinases. Based on the kinome data, we tested the antiviral effects of kinase inhibitors and other compounds, several of which are in clinical use or development. Using a novel flow cytometry-based assay and a fluorescent reporter virus we identified three compounds that inhibited HCMV replication with IC50 values of <1 μm, and at doses that were not toxic to uninfected cells. The most potent inhibitor of HCMV replication was OTSSP167 (IC50 <1.2 nm), a MELK inhibitor, blocked HCMV early gene expression and viral DNA accumulation, resulting in a >3 log decrease in virus replication. These results show the utility of MIB-MS kinome profiling for identifying existing kinase inhibitors that can potentially be repurposed as novel antiviral drugs.
Collapse
Affiliation(s)
- Kyle C Arend
- From the ‡Department of Microbiology & Immunology
- ¶Lineberger Comprehensive Cancer Center
| | - Erik M Lenarcic
- From the ‡Department of Microbiology & Immunology
- ¶Lineberger Comprehensive Cancer Center
| | - Heather A Vincent
- From the ‡Department of Microbiology & Immunology
- ¶Lineberger Comprehensive Cancer Center
| | - Naim Rashid
- ¶Lineberger Comprehensive Cancer Center
- ‖Department of Biostatistics
| | - Eric Lazear
- From the ‡Department of Microbiology & Immunology
- ¶Lineberger Comprehensive Cancer Center
| | | | | | | | - Laura E Herring
- §Department of Pharmacology
- **UNC Michael Hooker Proteomics Core Facility University of North Carolina, Chapel Hill, 27599 North Carolina
| | | | - Lee M Graves
- §Department of Pharmacology
- **UNC Michael Hooker Proteomics Core Facility University of North Carolina, Chapel Hill, 27599 North Carolina
| | - Nathaniel J Moorman
- From the ‡Department of Microbiology & Immunology,
- ¶Lineberger Comprehensive Cancer Center
| |
Collapse
|
9
|
Rieder FJJ, Kastner MT, Hartl M, Puchinger MG, Schneider M, Majdic O, Britt WJ, Djinović-Carugo K, Steininger C. Human cytomegalovirus phosphoproteins are hypophosphorylated and intrinsically disordered. J Gen Virol 2017; 98:471-485. [PMID: 27959783 DOI: 10.1099/jgv.0.000675] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Protein phosphorylation has important regulatory functions in cell homeostasis and is tightly regulated by kinases and phosphatases. The tegument of human cytomegalovirus (CMV) contains not only several proteins reported to be extensively phosphorylated but also cellular protein phosphatases (PP1 and PP2A). To investigate this apparent inconsistency, we evaluated the phosphorylation status of the tegument proteins pUL32 and pp65 by enzymatic dephosphorylation and MS. Enzymatic dephosphorylation with bacterial λ phosphatase, but not with PP1, shifted the pUL32-specific signal on reducing SDS-PAGE from ~150 to ~148 kDa, a mass still much larger than the ~118 kDa obtained from our diffusion studies and from the calculated protein mass of ~113 kDa. Remarkably, inhibition of phosphatases through treatment with the phosphatase inhibitors calyculin A and okadaic acid resulted in a shift to ~190 or ~180 kDa, respectively, indicating that a considerable number of potential phosphorylated residues on pUL32 are not phosphorylated under normal conditions. MS revealed a general state of hypophosphorylation of CMV phosphoproteins with only 17 phosphorylated residues detected on pUL32 and 19 on pp65, respectively. Moreover, bioinformatics analysis shows that the C-terminal two-thirds of pUL32 are intrinsically disordered and that most phosphorylations map to this region. In conclusion, we show that important CMV tegument proteins are indeed phosphorylated, though to a lesser extent than previously reported, and the difference in mobility on SDS-PAGE and calculated mass of pUL32 may not be attributed to phosphorylation but more likely due to the partially intrinsically disordered nature of pUL32.
Collapse
Affiliation(s)
- Franz J J Rieder
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Marie-Theres Kastner
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Markus Hartl
- Mass Spectrometry Facility, Max F. Perutz Laboratories, Vienna Biocenter, Vienna, Austria
| | - Martin G Puchinger
- Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Martina Schneider
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| | - Otto Majdic
- Center for Pathophysiology, Infectiology and Immunology, Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | - William J Britt
- Department of Pediatrics, Children's Hospital, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kristina Djinović-Carugo
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia.,Department of Structural and Computational Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Christoph Steininger
- Department of Medicine I, Division of Infectious Diseases and Tropical Medicine, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
10
|
Beelontally R, Wilkie GS, Lau B, Goodmaker CJ, Ho CMK, Swanson CM, Deng X, Wang J, Gray NS, Davison AJ, Strang BL. Identification of compounds with anti-human cytomegalovirus activity that inhibit production of IE2 proteins. Antiviral Res 2016; 138:61-67. [PMID: 27956134 PMCID: PMC5244968 DOI: 10.1016/j.antiviral.2016.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/04/2016] [Accepted: 12/05/2016] [Indexed: 01/01/2023]
Abstract
Using a high throughput screening methodology we surveyed a collection of largely uncharacterized validated or suspected kinase inhibitors for anti-human cytomegalovirus (HCMV) activity. From this screen we identified three structurally related 5-aminopyrazine compounds (XMD7-1, -2 and -27) that inhibited HCMV replication in virus yield reduction assays at low micromolar concentrations. Kinase selectivity assays indicated that each compound was a kinase inhibitor capable of inhibiting a range of cellular protein kinases. Western blotting and RNA sequencing demonstrated that treatment of infected cells with XMD7 compounds resulted in a defect in the production of the major HCMV transcriptional transactivator IE2 proteins (IE2-86, IE2-60 and IE2-40) and an overall reduction in transcription from the viral genome. However, production of certain viral proteins was not compromised by treatment with XMD7 compounds. Thus, these novel anti-HCMV compounds likely inhibited transcription from the viral genome and suppressed production of a subset of viral proteins by inhibiting IE2 protein production. High throughput screening identified novel kinase inhibitors that inhibit HCMV protein production. 5-aminopyrazine compounds (XMD7-1, -2 and -27) have anti-HCMV activity. XMD7 compounds inhibited production of HCMV IE2 proteins.
Collapse
Affiliation(s)
- Rooksarr Beelontally
- Institute of Infection & Immunity, St George's, University of London, London, UK
| | - Gavin S Wilkie
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Betty Lau
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Charles J Goodmaker
- Institute of Infection & Immunity, St George's, University of London, London, UK
| | - Catherine M K Ho
- Institute of Infection & Immunity, St George's, University of London, London, UK
| | - Chad M Swanson
- Department of Infectious Diseases, King's College London, London, UK
| | - Xianming Deng
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, MA, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Jinhua Wang
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, MA, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Nathanael S Gray
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, MA, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Andrew J Davison
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Blair L Strang
- Institute of Infection & Immunity, St George's, University of London, London, UK; Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
11
|
Phosphorylation of Golgi Peripheral Membrane Protein Grasp65 Is an Integral Step in the Formation of the Human Cytomegalovirus Cytoplasmic Assembly Compartment. mBio 2016; 7:mBio.01554-16. [PMID: 27703074 PMCID: PMC5050342 DOI: 10.1128/mbio.01554-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Human cytomegalovirus (HCMV) is the largest member of the Herpesviridae and represents a significant cause of disease. During virus replication, HCMV alters cellular functions to facilitate its replication, including significant reorganization of the secretory and endocytic pathways of the infected cell. A defining morphologic change of the infected cell is the formation of a membranous structure in the cytoplasm that is designated the virion assembly compartment (AC), which consists of virion structural proteins surrounded by cellular membranes. The loss of normal Golgi compartment morphology and its relocalization from a juxtanuclear ribbonlike structure to a series of concentric rings on the periphery of the AC represents a readily recognized reorganization of cellular membranes in the HCMV-infected cell. Although trafficking of viral proteins to this compartment is required for the assembly of infectious virions, the functional significance of the reorganization of intracellular membranes like the Golgi membranes into the AC in the assembly of infectious virus remains understudied. In this study, we determined that Golgi membrane ribbon fragmentation increased during the early cytoplasmic phase of virion assembly and that Golgi membrane fragmentation in infected cells was dependent on the phosphorylation of an integral cis-Golgi protein, Grasp65. Inhibition of Golgi membrane fragmentation and of its reorganization into the AC resulted in decreased production of infectious particles and alteration of the incorporation of an essential protein into the envelope of the mature virion. These results demonstrated the complexity of the virus-host cell interactions required for efficient assembly of this large DNA virus. The human cytomegalovirus (HCMV)-induced reorganization of intracellular membranes that is required for the formation of the viral assembly compartment (AC) has been an area of study over the last 20 years. The significance of this virus-induced structure has been evinced by the results of several studies which showed that relocalization of viral proteins to the AC was required for efficient assembly of infectious virus. In this study, we have identified a mechanism for the fragmentation of the Golgi ribbon in the infected cell en route to AC morphogenesis. Identification of this fundamental process during HCMV replication allowed us to propose that the functional role of Golgi membrane reorganization during HCMV infection was the concentration of viral structural proteins and subviral structures into a single intracellular compartment in order to facilitate efficient protein-protein interactions and the virion protein trafficking required for the assembly of this large and structurally complex virus.
Collapse
|
12
|
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.
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
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.
Collapse
|
16
|
Li H, Mao G, Carlson J, Leng SX. A novel flow cytometry-based tool for determining the efficiency of human cytomegalovirus infection in THP-1 derived macrophages. J Virol Methods 2015; 221:127-30. [PMID: 25958130 DOI: 10.1016/j.jviromet.2015.04.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 04/24/2015] [Accepted: 04/25/2015] [Indexed: 10/23/2022]
Abstract
Human cytomegalovirus (hCMV) is a ubiquitous pathogen that causes congenital infection and severe infections in immunocompromised patients. Chronic hCMV infection may also play an important role in immunosenescence and adverse health outcomes in older adults. THP-1, a human monocytic cell line and its derived macrophages serve as a useful cell culture model for mechanistic studies of hCMV infection and its underlying biology. A major methodological challenge is the lack of a quick and reliable tool to accurately determine the efficiency of hCMV infection in THP-1 derived macrophages. In this study, we developed a flow cytometry based method using commercially available monoclonal antibody (MAb) against hCMV immediate early (IE) antigen that can accurately determine infection efficiency. We used 0.5% formaldehyde for fixation, 90% methanol for permeabilization, and incubation with FITC conjugated MAb at 37°C. The method was tested by hCMV infection with laboratory Towne strain in the presence or absence of hydrocortisone. It was also compared with the routine flow cytometry protocol using Cytofix/Cytoperm solution and with immunofluorescence. The results indicate that this new method is reliable and time saving for accurate determination of infection efficiency. It may facilitate further investigations into the underlying biological mechanisms of hCMV infection.
Collapse
Affiliation(s)
- Huifen Li
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, 5505 Hopkins Bayview Circle, Baltimore, MD 21224, USA
| | - Genxiang Mao
- Zhejiang Provincial Key Lab of Geriatrics, Zhejiang Hospital, Hangzhou, Zhejiang Province, China
| | - Joshua Carlson
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, 5505 Hopkins Bayview Circle, Baltimore, MD 21224, USA
| | - Sean X Leng
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, 5505 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
| |
Collapse
|
17
|
Inhibition of human cytomegalovirus replication by artemisinins: effects mediated through cell cycle modulation. Antimicrob Agents Chemother 2015; 59:3870-9. [PMID: 25870074 DOI: 10.1128/aac.00262-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/09/2015] [Indexed: 12/15/2022] Open
Abstract
Artemisinin-derived monomers and dimers inhibit human cytomegalovirus (CMV) replication in human foreskin fibroblasts (HFFs). The monomer artesunate (AS) inhibits CMV at micromolar concentrations, while dimers inhibit CMV replication at nanomolar concentrations, without increased toxicity in HFFs. We report on the variable anti-CMV activity of AS compared to the consistent and reproducible CMV inhibition by dimer 606 and ganciclovir (GCV). Investigation of this phenomenon revealed that the anti-CMV activity of AS correlated with HFFs synchronized to the G0/G1 stage of the cell cycle. In contact-inhibited serum-starved HFFs or cells arrested at early/late G1 with specific checkpoint regulators, AS and dimer 606 efficiently inhibited CMV replication. However, in cycling HFFs, in which CMV replication was productive, virus inhibition by AS was significantly reduced, but inhibition by dimer 606 and GCV was maintained. Cell cycle analysis in noninfected HFFs revealed that AS induced early G1 arrest, while dimer 606 partially blocked cell cycle progression. In infected HFFs, AS and dimer 606 prevented the progression of cell cycle toward the G1/S checkpoint. AS reduced the expression of cyclin-dependent kinases (CDK) 2, 4, and 6 in noninfected cycling HFFs, while the effect of dimer 606 on these CDKs was moderate. Neither compound affected CDK expression in noninfected contact-inhibited HFFs. In CMV-infected cells, AS activity correlated with reduced CDK2 levels. CMV inhibition by AS and dimer 606 also correlated with hypophosphorylation (activity) of the retinoblastoma protein (pRb). AS activity was strongly associated with pRb hypophosphorylation, while its reduced anti-CMV activity was marked by pRb phosphorylation. Roscovitine, a CDK2 inhibitor, antagonized the anti-CMV activities of AS and dimer 606. These data suggest that cell cycle modulation through CDKs and pRb might play a role in the anti-CMV activities of artemisinins. Proteins involved in this modulation may be identified and targeted for CMV inhibition.
Collapse
|
18
|
Abstract
Concerted efforts of tumor immunologists over more than two decades contributed numerous well-defined tumor antigens, many of which were promptly developed into cancer vaccines and tested in animal models and in clinical trials. Encouraging results from animal models were seldom recapitulated in clinical trials. The impediment to greater success of these vaccines has been their exclusive use for cancer therapy. What clinical trials primarily revealed were the numerous ways in which cancer and/or standard treatments for cancer could suppress the patient's immune system, making it very difficult to elicit effective immunity with therapeutic vaccines. In contrast, there is an extensive database of information from experiments in appropriate animal models showing that prophylactic vaccination is highly effective and safe. There are also studies that show that healthy people have immune responses against antigens expressed on tumors, some generated in response to viral infections and others in response to various nonmalignant acute inflammatory events. These immune responses do not appear to be dangerous and do not cause autoimmunity. Epidemiology studies have shown that these immune responses may reduce cancer risk significantly. Vaccines based on tumor antigens that are expressed differentially between tumors and normal cells and can stimulate immunity, and for which safety and efficacy have been proved in animal models and to the extent possible in therapeutic clinical trials, should be considered prime candidates for prophylactic cancer vaccines.
Collapse
Affiliation(s)
- Olivera J Finn
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| |
Collapse
|
19
|
Spector DH. Human cytomegalovirus riding the cell cycle. Med Microbiol Immunol 2015; 204:409-19. [PMID: 25776080 DOI: 10.1007/s00430-015-0396-z] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 02/19/2015] [Indexed: 12/25/2022]
Abstract
Human cytomegalovirus (HCMV) infection modulates the host cell cycle to create an environment that is optimal for viral gene expression, DNA replication, and production of infectious virus. The virus mostly infects quiescent cells and thus must push the cell into G1 phase of the cell cycle to co-opt the cellular mechanisms that could be used for DNA synthesis. However, at the same time, cellular functions must be subverted such that synthesis of viral DNA is favored over that of the host. The molecular mechanisms by which this is accomplished include altered RNA transcription, changes in the levels and activity of cyclin-dependent kinases, and other proteins involved in cell cycle control, posttranslational modifications of proteins, modulation of protein stability through targeted effects on the ubiquitin-proteasome degradation pathway, and movement of proteins to different cellular locations. When the cell is in the optimal G0/G1 phase, multiple signaling pathways are altered to allow rapid induction of viral gene expression once negative factors have been eliminated. For the most part, the cell cycle will stop prior to initiation of host cell DNA synthesis (S phase), although many cell cycle proteins characteristic of the S/G2/M phase accumulate. The environment of a cell progressing through the cell cycle and dividing is not favorable for viral replication, and HCMV has evolved ways to sense whether cells are in S/G2 phase, and if so, to prevent initiation of viral gene expression until the cells cycle back to G1. A major target of HCMV is the anaphase-promoting complex E3 ubiquitin ligase, which is responsible for the ubiquitination and subsequent degradation of cyclins A and B and other cell cycle proteins at specific phases in the cell cycle. This review will discuss the effects of HCMV infection on cell cycle regulatory pathways, with the focus on selected viral proteins that are responsible for these effects.
Collapse
Affiliation(s)
- Deborah H Spector
- Department of Cellular and Molecular Medicine, The Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, 92093-0712, USA,
| |
Collapse
|
20
|
Sharma M, Coen DM. Comparison of effects of inhibitors of viral and cellular protein kinases on human cytomegalovirus disruption of nuclear lamina and nuclear egress. J Virol 2014; 88:10982-5. [PMID: 24965476 PMCID: PMC4178862 DOI: 10.1128/jvi.01391-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 06/20/2014] [Indexed: 12/30/2022] Open
Abstract
Human cytomegalovirus (HCMV) kinase UL97 is required for efficient nuclear lamina disruption during nuclear egress. However, cellular protein kinase C (PKC) has been implicated in this process in other systems. Comparing the effects of UL97 and cellular kinase inhibitors on HCMV nuclear egress confirms a role for UL97 in lamina disruption and nuclear egress. A pan-PKC inhibitor did not affect lamina disruption but did reduce the number of cytoplasmic capsids more than the number of nuclear capsids.
Collapse
Affiliation(s)
- Mayuri Sharma
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Donald M Coen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
21
|
New Herpes Simplex Virus Replication Targets. Antiviral Res 2014. [DOI: 10.1128/9781555815493.ch20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
22
|
Holcakova J, Muller P, Tomasec P, Hrstka R, Nekulova M, Krystof V, Strnad M, Wilkinson GWG, Vojtesek B. Inhibition of post-transcriptional RNA processing by CDK inhibitors and its implication in anti-viral therapy. PLoS One 2014; 9:e89228. [PMID: 24586613 PMCID: PMC3931720 DOI: 10.1371/journal.pone.0089228] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 01/17/2014] [Indexed: 01/31/2023] Open
Abstract
Cyclin-dependent kinases (CDKs) are key regulators of the cell cycle and RNA polymerase II mediated transcription. Several pharmacological CDK inhibitors are currently in clinical trials as potential cancer therapeutics and some of them also exhibit antiviral effects. Olomoucine II and roscovitine, purine-based inhibitors of CDKs, were described as effective antiviral agents that inhibit replication of a broad range of wild type human viruses. Olomoucine II and roscovitine show high selectivity for CDK7 and CDK9, with important functions in the regulation of RNA polymerase II transcription. RNA polymerase II is necessary for viral transcription and following replication in cells. We analyzed the effect of inhibition of CDKs by olomoucine II on gene expression from viral promoters and compared its effect to widely-used roscovitine. We found that both roscovitine and olomoucine II blocked the phosphorylation of RNA polymerase II C-terminal domain. However the repression of genes regulated by viral promoters was strongly dependent on gene localization. Both roscovitine and olomoucine II inhibited expression only when the viral promoter was not integrated into chromosomal DNA. In contrast, treatment of cells with genome-integrated viral promoters increased their expression even though there was decreased phosphorylation of the C-terminal domain of RNA polymerase II. To define the mechanism responsible for decreased gene expression after pharmacological CDK inhibitor treatment, the level of mRNA transcription from extrachromosomal DNA was determined. Interestingly, our results showed that inhibition of RNA polymerase II C-terminal domain phosphorylation increased the number of transcribed mRNAs. However, some of these mRNAs were truncated and lacked polyadenylation, which resulted in decreased translation. These results suggest that phosphorylation of RNA polymerase II C-terminal domain is critical for linking transcription and posttrancriptional processing of mRNA expressed from extrachromosomal DNA.
Collapse
Affiliation(s)
- Jitka Holcakova
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic
| | - Petr Muller
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic
| | - Peter Tomasec
- School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Roman Hrstka
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic
| | - Marta Nekulova
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic
| | - Vladimir Krystof
- Laboratory of Growth Regulators, Faculty of Science, Palacky University, Olomouc, Czech Republic
- Institute of Experimental Botany AS CR, Olomouc, Czech Republic
| | - Miroslav Strnad
- Laboratory of Growth Regulators, Faculty of Science, Palacky University, Olomouc, Czech Republic
- Institute of Experimental Botany AS CR, Olomouc, Czech Republic
| | | | - Borivoj Vojtesek
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Brno, Czech Republic
- * E-mail:
| |
Collapse
|
23
|
Caffarelli N, Fehr AR, Yu D. Cyclin A degradation by primate cytomegalovirus protein pUL21a counters its innate restriction of virus replication. PLoS Pathog 2013; 9:e1003825. [PMID: 24385906 PMCID: PMC3873445 DOI: 10.1371/journal.ppat.1003825] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 10/28/2013] [Indexed: 12/13/2022] Open
Abstract
Cyclin A is critical for cellular DNA synthesis and S phase progression of the cell cycle. Human cytomegalovirus (HCMV) can reduce cyclin A levels and block cellular DNA synthesis, and cyclin A overexpression can repress HCMV replication. This interaction has only been previously observed in HCMV as murine CMV does not downregulate cyclin A, and the responsible viral factor has not been identified. We previously reported that the HCMV protein pUL21a disrupted the anaphase-promoting complex (APC), but a point mutant abrogating this activity did not phenocopy a UL21a-deficient virus, suggesting that pUL21a has an additional function. Here we identified a conserved arginine-x-leucine (RxL) cyclin-binding domain within pUL21a, which allowed pUL21a to interact with cyclin A and target it for proteasome degradation. Homologous pUL21a proteins from both chimpanzee and rhesus CMVs also contained the RxL domain and similarly degraded cyclin A, indicating that this function is conserved in primate CMVs. The RxL point mutation disabled the virus' ability to block cellular DNA synthesis and resulted in a growth defect similar to pUL21a-deficient virus. Importantly, knockdown of cyclin A rescued growth of UL21a-deficient virus. Together, these data show that during evolution, the pUL21a family proteins of primate CMVs have acquired a cyclin-binding domain that targets cyclin A for degradation, thus neutralizing its restriction on virus replication. Finally, the combined proteasome-dependent degradation of pUL21a and its cellular targets suggests that pUL21a may act as a novel suicide protein, targeting its protein cargos for destruction. Cyclins are evolutionarily conserved proteins that associate with cyclin-dependent kinases (CDKs) to regulate phosphorylation of multiple substrates to promote cell-cycle progression. Many viruses manipulate the cell cycle in order to create an environment suitable for replication; however, only few examples exist where viruses modulate cyclin activity. Here, we identified a cyclin-binding domain within the human cytomegalovirus (HCMV) protein pUL21a that confers its ability to interact with cyclin A and target it for proteasome degradation. Cyclin A promotes cellular DNA replication, which consumes important enzymes and metabolites needed for viral replication, making it important for large viruses like HCMV to block this protein's activity. In accord, the ability of pUL21a to degrade cyclin A was necessary for the virus to block cellular DNA replication and promote viral replication. Importantly, ablating cyclin A expression restored replication to a virus lacking pUL21a, demonstrating that cyclin A has the intrinsic ability to restrict viral replication, but is specifically countered by pUL21a. Together with our previous work showing that pUL21a also regulates the anaphase-promoting complex, another master cell cycle regulator, our studies have now revealed that HCMV has elegantly evolved dual functions within one protein targeting the cell cycle machinery for viral replication.
Collapse
Affiliation(s)
- Nicolas Caffarelli
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Anthony R. Fehr
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Dong Yu
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- * E-mail: ,
| |
Collapse
|
24
|
The cyclin-dependent kinase ortholog pUL97 of human cytomegalovirus interacts with cyclins. Viruses 2013; 5:3213-30. [PMID: 24351800 PMCID: PMC3967168 DOI: 10.3390/v5123213] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 12/08/2013] [Accepted: 12/09/2013] [Indexed: 11/23/2022] Open
Abstract
The human cytomegalovirus (HCMV)-encoded protein kinase, pUL97, is considered a cyclin-dependent kinase (CDK) ortholog, due to shared structural and functional characteristics. The primary mechanism of CDK activation is binding to corresponding cyclins, including cyclin T1, which is the usual regulatory cofactor of CDK9. This study provides evidence of direct interaction between pUL97 and cyclin T1 using yeast two-hybrid and co-immunoprecipitation analyses. Confocal immunofluorescence revealed partial colocalization of pUL97 with cyclin T1 in subnuclear compartments, most pronounced in viral replication centres. The distribution patterns of pUL97 and cyclin T1 were independent of HCMV strain and host cell type. The sequence domain of pUL97 responsible for the interaction with cyclin T1 was between amino acids 231–280. Additional co-immunoprecipitation analyses showed cyclin B1 and cyclin A as further pUL97 interaction partners. Investigation of the pUL97-cyclin T1 interaction in an ATP consumption assay strongly suggested phosphorylation of pUL97 by the CDK9/cyclin T1 complex in a substrate concentration-dependent manner. This is the first demonstration of interaction between a herpesviral CDK ortholog and cellular cyclins.
Collapse
|
25
|
Chia YL, Ng CH, Lashmit P, Chu KL, Lew QJ, Ho JP, Lim HL, Nissom PM, Stinski MF, Chao SH. Inhibition of human cytomegalovirus replication by overexpression of CREB1. Antiviral Res 2013; 102:11-22. [PMID: 24316029 DOI: 10.1016/j.antiviral.2013.11.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 10/28/2013] [Accepted: 11/25/2013] [Indexed: 01/01/2023]
Abstract
Expression of the human cytomegalovirus (HCMV) major immediate-early (MIE) genes is regulated by a strong enhancer-containing promoter with multiple binding sites for various transcription factors, including cyclic AMP response element binding protein 1 (CREB1). Here we show that overexpression of CREB1 potently blocked MIE transcription and HCMV replication. Surprisingly, CREB1 still exhibited strong inhibition of the MIE promoter when all five CREB binding sites within the enhancer were mutated, suggesting that CREB1 regulated the MIE gene expression indirectly. Promoter deletion analysis and site-directed mutagenesis identified the region between -130 and -50 upstream of the transcription start site of the MIE gene as the "CREB1 responsive region". Mutations of SP1/3 and NF-κB binding sites within this region interrupted the inhibitory effect induced by CREB1 overexpression. Our findings suggest that overexpression of CREB1 can cause repression of HCMV replication and may contribute to the development of new anti-HCMV strategies.
Collapse
Affiliation(s)
- Yi Ling Chia
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Chew Har Ng
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Philip Lashmit
- Department of Microbiology, University of Iowa, 51 Newton Rd., 3-772 Bowen Science Building, Iowa City, IA 52242, USA
| | - Kai Ling Chu
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Qiao Jing Lew
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Jia Pei Ho
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Hsueh Lee Lim
- Microarray Groups, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Peter Morin Nissom
- Microarray Groups, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Mark F Stinski
- Department of Microbiology, University of Iowa, 51 Newton Rd., 3-772 Bowen Science Building, Iowa City, IA 52242, USA
| | - Sheng-Hao Chao
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore; Department of Microbiology, National University of Singapore, Block MD4, 5 Science Drive 2, Singapore 117597, Singapore.
| |
Collapse
|
26
|
Li R, Hayward SD. Potential of protein kinase inhibitors for treating herpesvirus-associated disease. Trends Microbiol 2013; 21:286-95. [PMID: 23608036 DOI: 10.1016/j.tim.2013.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Revised: 03/24/2013] [Accepted: 03/26/2013] [Indexed: 11/29/2022]
Abstract
Herpesviruses are ubiquitous human pathogens that establish lifelong persistent infections. Clinical manifestations range from mild self-limiting outbreaks such as childhood rashes and cold sores to the more severe and life-threatening outcomes of disseminated infection, encephalitis, and cancer. Nucleoside analog drugs that target viral DNA replication provide the primary means of treatment. However, extended use of these drugs can result in selection for drug-resistant strains, particularly in immunocompromised patients. In this review we will present recent observations about the participation of cellular protein kinases in herpesvirus biology and discuss the potential for targeting these protein kinases as well as the herpesvirus-encoded protein kinases as an anti-herpesvirus therapeutic strategy.
Collapse
Affiliation(s)
- Renfeng Li
- Viral Oncology Program, Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA.
| | | |
Collapse
|
27
|
Wennhold K, Theurich S, von Bergwelt-Baildon M. Cyclin A1, a promising tumor antigen: the devil is in the amino acids. Expert Rev Anticancer Ther 2013; 13:243-5. [PMID: 23477508 DOI: 10.1586/era.12.175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
28
|
Sanchez V, Dong JJ, Battley J, Jackson KN, Dykes BC. Human cytomegalovirus infection of THP-1 derived macrophages reveals strain-specific regulation of actin dynamics. Virology 2012; 433:64-72. [PMID: 22874068 DOI: 10.1016/j.virol.2012.07.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 05/21/2012] [Accepted: 07/16/2012] [Indexed: 01/01/2023]
Abstract
Human cytomegalovirus (HCMV) remains latent in cells of the myeloid lineage after primary infection. The THP-1 monocytic cell line is conditionally permissive for infection and has been used primarily to study the process of HCMV reactivation when the cells are induced to differentiate. In the present report, we characterized lytic infection in THP-1 derived macrophages using two strains of HCMV, Towne and BAC-derived TR. Our findings indicate that these cells express viral genes of all three kinetic classes and produce extracellular virus, but that there is a delay in these processes relative to productively infected fibroblasts. Importantly, our studies in THP-1 derived macrophages revealed strain-specific differences in pp65 trafficking and actin dynamics. Based on these observations, our studies indicate that differentiated THP-1 cells can serve as a valuable model for lytic infection.
Collapse
Affiliation(s)
- V Sanchez
- Texas A&M Health Science Center, College of Medicine, Department of Microbial and Molecular Pathogenesis, College Station, TX 77843, USA.
| | | | | | | | | |
Collapse
|
29
|
Abstract
Viral replication is a complex process relying on a network of interacting viral and cellular proteins, in which particularly protein kinases play an important regulatory role. The specific phosphorylation of substrate proteins induces activation, inactivation, or other functional modification and thus determines virus-host cell interregulation. During herpesviral infections, both viral and cellular protein kinases are expressed and provide activities crucial for the efficiency of virus replication. The protein kinase pUL97 encoded by human cytomegalovirus (HCMV) is a multifunctional regulatory enzyme which exerts strong regulatory effects on early and late steps of the viral replication cycle. A number of interacting proteins and substrates of pUL97 have been described, including retinoblastoma (Rb) protein, nuclear lamins and viral pUL69. Recently, it was demonstrated that pUL97 has structural and functional resemblance to cyclin-dependent protein kinases (CDKs) and thus represents a CDK ortholog. pUL97 can phosphorylate and inactivate Rb, resulting in a stimulation of cell cycle progression. In addition, the association of pUL97 activity with nucleocytoplasmic export of viral capsids has been demonstrated by several investigators. We could show that pUL97 is able to phosphorylate nuclear lamins and to contribute to the HCMV-induced reorganization of the nuclear lamina. On the basis of very recent findings, it is becoming increasingly clear that pUL97 is a component of a multiprotein nuclear egress complex (NEC). The NEC contains a small number of egress proteins involved in the recruitment of protein kinases, such as pUL97 and cellular protein kinase C (PKC), to specific sites of the nuclear lamina. Current information about the composition, function, and regulatory complexity of the NEC leads to a mechanistic concept which may set the key features of HCMV nuclear egress in a new light.
Collapse
|
30
|
Sites and roles of phosphorylation of the human cytomegalovirus DNA polymerase subunit UL44. Virology 2011; 417:268-80. [PMID: 21784501 DOI: 10.1016/j.virol.2011.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 04/12/2011] [Accepted: 06/11/2011] [Indexed: 12/27/2022]
Abstract
The human cytomegalovirus DNA polymerase subunit UL44 is a phosphoprotein, but its sites and roles of phosphorylation have not been investigated. We compared sites of phosphorylation of UL44 in vitro by the viral protein kinase UL97 and cyclin-dependent kinase 1 with those in infected cells. Transient treatment of infected cells with a UL97 inhibitor greatly reduced labeling of two minor UL44 phosphopeptides. Viruses containing alanine substitutions of most UL44 residues that are phosphorylated in infected cells exhibited at most modest effects on viral DNA synthesis and yield. However, substitution of highly phosphorylated sites adjacent to the nuclear localization signal abolished viral replication. The results taken together are consistent with UL44 being phosphorylated directly by UL97 during infection, and a crucial role for phosphorylation-mediated nuclear localization of UL44 for viral replication, but lend little support to the widely held hypothesis that UL97-mediated phosphorylation of UL44 is crucial for viral DNA synthesis.
Collapse
|
31
|
Feichtinger S, Stamminger T, Müller R, Graf L, Klebl B, Eickhoff J, Marschall M. Recruitment of cyclin-dependent kinase 9 to nuclear compartments during cytomegalovirus late replication: importance of an interaction between viral pUL69 and cyclin T1. J Gen Virol 2011; 92:1519-1531. [PMID: 21450947 DOI: 10.1099/vir.0.030494-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cyclin-dependent protein kinases (CDKs) are important regulators of cellular processes and are functionally integrated into the replication of human cytomegalovirus (HCMV). Recently, a regulatory impact of CDK activity on the viral mRNA export factor pUL69 was shown. Here, specific aspects of the mode of interaction between CDK9/cyclin T1 and pUL69 are described. Intracellular localization was studied in the presence of a novel selective CDK9 inhibitor, R22, which exerts anti-cytomegaloviral activity in vitro. A pronounced R22-induced formation of nuclear speckled aggregation of pUL69 was demonstrated. Multi-labelling confocal laser-scanning microscopy revealed that CDK9 and cyclin T1 co-localized perfectly with pUL69 in individual speckles. The effects were similar to those described recently for the broad CDK inhibitor roscovitine. Co-immunoprecipitation and yeast two-hybrid analyses showed that cyclin T1 interacted with both CDK9 and pUL69. The interaction region of pUL69 for cyclin T1 could be attributed to aa 269-487. Moreover, another component of CDK inhibitor-induced speckled aggregates was identified with RNA polymerase II, supporting earlier reports that strongly suggested an association of pUL69 with transcription complexes. Interestingly, when using a UL69-deleted recombinant HCMV, no speckled aggregates were formed by CDK inhibitor treatment. This indicated that pUL69 is the defining component of aggregates and generally may represent a crucial viral interactor of cyclin T1. In conclusion, these data emphasize that HCMV inter-regulation with CDK9/cyclin T1 is at least partly based on a pUL69-cylin T1 interaction, thus contributing to the importance of CDK9 for HCMV replication.
Collapse
Affiliation(s)
- Sabine Feichtinger
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Thomas Stamminger
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Regina Müller
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - Laura Graf
- 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
| |
Collapse
|
32
|
Cramer DW, Finn OJ. Epidemiologic perspective on immune-surveillance in cancer. Curr Opin Immunol 2011; 23:265-71. [PMID: 21277761 DOI: 10.1016/j.coi.2011.01.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 01/06/2011] [Indexed: 10/18/2022]
Abstract
Common 'themes' in epidemiology related to cancer risk beg a comprehensive mechanistic explanation. As people age, risk for cancer increases. Obesity and smoking increase the risk for many types of cancer. History of febrile childhood diseases lowers the risk for melanomas, leukemias, non-Hodgkin's lymphoma (NHL), and ovarian cancer. Increasing number of ovulatory cycles uninterrupted by pregnancies correlate positively with breast, endometrial, and ovarian cancer risk while pregnancies and breastfeeding lower the risk for these cancers as well as cancers of the colon, lung, pancreas, and NHL. Chronic inflammatory events such as endometriosis or mucosal exposure to talc increase the risk for several types of cancer. Mechanisms so far considered are site specific and do not explain multiple associations. We propose that most of these events affect cancer immunosurveillance by changing the balance between an effective immune response and immune tolerance of an emerging cancer. We review recently published data that suggest that immune mechanisms underlie most of these observed epidemiologic associations with cancer risk.
Collapse
Affiliation(s)
- Daniel W Cramer
- Obsterics-Gynecology Epidemiology Center, Department of Obsterics and Gynecology, Brigham and Women's Hospital, Boston, MA 02115, USA.
| | | |
Collapse
|
33
|
Nascimento R, Costa H, Dias JD, Parkhouse RME. MHV-68 Open Reading Frame 20 is a nonessential gene delaying lung viral clearance. Arch Virol 2010; 156:375-86. [PMID: 21104281 DOI: 10.1007/s00705-010-0862-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 11/08/2010] [Indexed: 11/24/2022]
Abstract
Recently, it has been demonstrated that the MHV-68 ORF20-encoded gene product induces cell-cycle arrest at the G2/M phase, followed by apoptosis. To study the role of this conserved gene in vivo, two independent ORF20-deficient MHV-68 viruses and their revertants were constructed. As the replication in vitro of both mutants followed similar kinetics to that of the wild-type and revertant viruses, ORF20 is therefore a nonessential virus gene. No cell cycle arrest could be observed upon infection of cells with wild type MHV-68 or mutant viruses. In addition, no major differences were detected between mock- and virus-infected cells when protein and inactivation levels of the mitotic promoter factor cdc2/cyclinB were analyzed. Following intranasal infection, the recovery of mutant, revertant and wild-type viruses in the lungs was similar. With the ORF20-deficient viruses, however, there was a significant delay of four days in clearance of virus from the lungs. Surprisingly, the magnitude and cell population distribution in the exudates of the lung was essentially similar to mice infected with wild-type, revertant or ORF20-deleted viruses. Subsequent establishment of latency was normal for both mutants, demonstrating that ORF20 does not play a critical role in establishment of a persistent infection. These results indicate that while expression of ORF20 may impact on the pathogenicity of the infection, the observed induction of G2/M arrest in ORF20-expressing cells may not be the primary function of ORF20 in the context of viral infection.
Collapse
Affiliation(s)
- R Nascimento
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande nº6, Apartado 14, 2779-558 Oeiras, Portugal
| | | | | | | |
Collapse
|
34
|
Alternative splicing of the human cytomegalovirus major immediate-early genes affects infectious-virus replication and control of cellular cyclin-dependent kinase. J Virol 2010; 85:804-17. [PMID: 21068259 DOI: 10.1128/jvi.01173-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The major immediate-early (MIE) gene locus of human cytomegalovirus (HCMV) is the master switch that determines the outcomes of both lytic and latent infections. Here, we provide evidence that alteration in the splicing of HCMV (Towne strain) MIE genes affects infectious-virus replication, movement through the cell cycle, and cyclin-dependent kinase activity. Mutation of a conserved 24-nucleotide region in MIE exon 4 increased the abundance of IE1-p38 mRNA and decreased the abundance of IE1-p72 and IE2-p86 mRNAs. An increase in IE1-p38 protein was accompanied by a slight decrease in IE1-p72 protein and a significant decrease in IE2-p86 protein. The mutant virus had growth defects, which could not be complemented by wild-type IE1-p72 protein in trans. The phenotype of the mutant virus could not be explained by an increase in IE1-p38 protein, but prevention of the alternate splice returned the recombinant virus to the wild-type phenotype. The lower levels of IE1-p72 and IE2-p86 proteins correlated with a delay in early and late viral gene expression and movement into the S phase of the cell cycle. Mutant virus-infected cells had significantly higher levels of cdk-1 expression and enzymatic activity than cells infected with wild-type virus. The mutant virus induced a round-cell phenotype that accumulated in the G(2)/M compartment of the cell cycle with condensation and fragmentation of the chromatin. An inhibitor of viral DNA synthesis increased the round-cell phenotype. The round cells were characteristic of an abortive viral infection.
Collapse
|
35
|
Zydek M, Hagemeier C, Wiebusch L. Cyclin-dependent kinase activity controls the onset of the HCMV lytic cycle. PLoS Pathog 2010; 6:e1001096. [PMID: 20844576 PMCID: PMC2936547 DOI: 10.1371/journal.ppat.1001096] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Accepted: 08/11/2010] [Indexed: 12/21/2022] Open
Abstract
The onset of human cytomegalovirus (HCMV) lytic infection is strictly synchronized with the host cell cycle. Infected G0/G1 cells support viral immediate early (IE) gene expression and proceed to the G1/S boundary where they finally arrest. In contrast, S/G2 cells can be infected but effectively block IE gene expression and this inhibition is not relieved until host cells have divided and reentered G1. During latent infection IE gene expression is also inhibited, and for reactivation to occur this block to IE gene expression must be overcome. It is only poorly understood which viral and/or cellular activities maintain the block to cell cycle or latency-associated viral IE gene repression and whether the two mechanisms may be linked. Here, we show that the block to IE gene expression during S and G2 phase can be overcome by both genotoxic stress and chemical inhibitors of cellular DNA replication, pointing to the involvement of checkpoint-dependent signaling pathways in controlling IE gene repression. Checkpoint-dependent rescue of IE expression strictly requires p53 and in the absence of checkpoint activation is mimicked by proteasomal inhibition in a p53 dependent manner. Requirement for the cyclin dependent kinase (CDK) inhibitor p21 downstream of p53 suggests a pivotal role for CDKs in controlling IE gene repression in S/G2 and treatment of S/G2 cells with the CDK inhibitor roscovitine alleviates IE repression independently of p53. Importantly, CDK inhibiton also overcomes the block to IE expression during quiescent infection of NTera2 (NT2) cells. Thus, a timely block to CDK activity not only secures phase specificity of the cell cycle dependent HCMV IE gene expression program, but in addition plays a hitherto unrecognized role in preventing the establishment of a latent-like state.
Collapse
Affiliation(s)
- Martin Zydek
- Children's Hospital, Laboratory for Molecular Biology, Charité Universitätsmedizin Berlin, Berlin, Germany
- Free University of Berlin, Faculty of Biology, Chemistry and Pharmacy, Berlin, Germany
| | - Christian Hagemeier
- Children's Hospital, Laboratory for Molecular Biology, Charité Universitätsmedizin Berlin, Berlin, Germany
- * E-mail: (LW); (CH)
| | - Lüder Wiebusch
- Children's Hospital, Laboratory for Molecular Biology, Charité Universitätsmedizin Berlin, Berlin, Germany
- * E-mail: (LW); (CH)
| |
Collapse
|
36
|
Klein-González N, Kondo E, von Bergwelt-Baildon MS. Cyclins against cancer: a novel family of tumor antigens? Immunotherapy 2010; 2:595-7. [DOI: 10.2217/imt.10.48] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Nela Klein-González
- Department I of Internal Medicine, University Hospital of Cologne, Cologne, Germany
| | - Eisei Kondo
- Department of Hematology & Oncology, Okayama University Hospital, Okayama, Japan
| | - Michael S von Bergwelt-Baildon
- Laboratory for Tumor & Transplantation Immunology & Stem Cell Transplantation Program, Department I of Internal Medicine, University Hospital Cologne, Kerpener Str. 62, 50924 Cologne, Germany
| |
Collapse
|
37
|
Sanchez V, Dong JJ. Alteration of lipid metabolism in cells infected with human cytomegalovirus. Virology 2010; 404:71-7. [PMID: 20552728 DOI: 10.1016/j.virol.2010.04.026] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The human cytomegalovirus (HCMV) envelope contains 12 virus-encoded glycoproteins and glycoprotein complexes but the lipid composition of the envelope has not been clearly defined. Given the specificity of the interactions between integral membrane proteins and lipids, it is likely that the lipid content of the virion envelope is regulated during infection. In an effort to determine the effects of HCMV infection on lipid metabolism, we have used PCR array technology to investigate how infection affects the expression of genes involved in lipoprotein signaling and cholesterol homeostasis pathways. Our results indicate that HCMV infection leads to down-regulation of the ABCA1 transporter. Decreased levels of ABCA1 appear to be the result of enhanced calpain-mediated cleavage in virus-infected cells. In addition, our data also show that HCMV infection inhibits the development of the foam cell phenotype in conditionally permissive THP-1 derived macrophages
Collapse
Affiliation(s)
- Veronica Sanchez
- Texas A&M Health Science Center, Department of Microbial and Molecular Pathogenesis, College Station, TX 77843-1266, USA.
| | | |
Collapse
|
38
|
Marschall M, Stamminger T. Molecular targets for antiviral therapy of cytomegalovirus infections. Future Microbiol 2009; 4:731-42. [PMID: 19659428 DOI: 10.2217/fmb.09.40] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Human cytomegalovirus infections are still associated with severe morbidity and mortality in immunocompromised individuals, despite the availability of five drugs that are currently licensed for antiviral therapy. Furthermore, human cytomegalovirus is the most frequent cause of congenital infections for which antiviral treatment options are very limited. Thus, the need for a potent, safe and well-tolerated antiviral drug remains. This review focuses on target molecules that are implicated in the development of innovative anticytomegaloviral approaches, such as viral immediate-early and DNA replication proteins, as well as regulatory protein kinases. Special emphasis is given to promising host factors, in particular the receptor tyrosine kinase PDGF and cyclin-dependent protein kinases, since a combined targeting of viral and cellular factors that are critical for viral replication may alleviate the emergence of drug-resistant virus variants.
Collapse
Affiliation(s)
- Manfred Marschall
- Institute for Clinical & Molecular Virology, University of Erlangen-Nuremberg, Schlossgarten 4, 91054 Erlangen, Germany.
| | | |
Collapse
|
39
|
Thomas M, Rechter S, Milbradt J, Auerochs S, Müller R, Stamminger T, Marschall M. Cytomegaloviral protein kinase pUL97 interacts with the nuclear mRNA export factor pUL69 to modulate its intranuclear localization and activity. J Gen Virol 2009; 90:567-578. [PMID: 19218201 DOI: 10.1099/vir.0.005827-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human cytomegalovirus encodes a number of phosphorylation-regulated proteins, including the autophosphorylating protein kinase pUL97 and the nuclear mRNA export factor pUL69. Recently, it was reported that the kinase inhibitor roscovitine induces an intranuclear aggregation of pUL69 in infected fibroblasts. Here, we demonstrate that pUL97-specific kinase inhibitors induce a similar pUL69 aggregation. Furthermore, a direct pUL69-pUL97 interaction was demonstrated by coimmunoprecipitation analyses. Deletion mapping identified the domains required for interaction in both proteins (1-140/478-532 in pUL69 and 231-336 in pUL97). Further analysis of the immunoprecipitates by in vitro kinase assays demonstrated the phosphorylation of pUL69 by pUL97. However, catalytically inactive mutants of pUL97 and interaction-negative fragments of pUL69 were phosphorylation-negative. Moreover, an analysis of the pUL69-mediated nuclear RNA export indicated a correlation of the export efficiency with the presence of active pUL97 kinase. These data suggest a specific pUL69-pUL97 interaction and pUL97-mediated phosphorylation which influences the regulatory activities of pUL69.
Collapse
Affiliation(s)
- Marco Thomas
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Sabine Rechter
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Jens Milbradt
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Sabrina Auerochs
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Regina Müller
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Thomas Stamminger
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, 91054 Erlangen, Germany
| |
Collapse
|
40
|
Rechter S, Scott GM, Eickhoff J, Zielke K, Auerochs S, Müller R, Stamminger T, Rawlinson WD, Marschall M. Cyclin-dependent Kinases Phosphorylate the Cytomegalovirus RNA Export Protein pUL69 and Modulate Its Nuclear Localization and Activity. J Biol Chem 2009; 284:8605-13. [PMID: 19179338 DOI: 10.1074/jbc.m805693200] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Replication of human cytomegalovirus (HCMV) is subject to regulation by cellular protein kinases. Recently, we and others reported that inhibition of cyclin-dependent protein kinases (CDKs) or the viral CDK ortholog pUL97 can induce intranuclear speckled aggregation of the viral mRNA export factor, pUL69. Here we provide the first evidence for a direct regulatory role of CDKs on pUL69 functionality. Although replication of all HCMV strains was dependent on CDK activity, we found strain-specific differences in the amount of CDK inhibitor-induced pUL69 aggregate formation. In all cases analyzed, the inhibitor-induced pUL69 aggregates were clearly localized within viral replication centers but not subnuclear splicing, pore complex, or aggresome structures. The CDK9 and cyclin T1 proteins colocalized with these pUL69 aggregates, whereas other CDKs behaved differently. Phosphorylation analyses in vivo and in vitro demonstrated pUL69 was strongly phosphorylated in HCMV-infected fibroblasts and that CDKs represent a novel class of pUL69-phosphorylating kinases. Moreover, the analysis of CDK inhibitors in a pUL69-dependent nuclear mRNA export assay provided evidence for functional impairment of pUL69 under suppression of CDK activity. Thus, our data underline the crucial importance of CDKs for HCMV replication, and indicate a direct impact of CDK9-cyclin T1 on the nuclear localization and activity of the viral regulator pUL69.
Collapse
Affiliation(s)
- Sabine Rechter
- Institute for Clinical and Molecular Virology, University of Erlangen-Nuremberg, Erlangen 91054, Germany, GPC Biotech AG, 82152 Martinsried, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Hamirally S, Kamil JP, Ndassa-Colday YM, Lin AJ, Jahng WJ, Baek MC, Noton S, Silva LA, Simpson-Holley M, Knipe DM, Golan DE, Marto JA, Coen DM. Viral mimicry of Cdc2/cyclin-dependent kinase 1 mediates disruption of nuclear lamina during human cytomegalovirus nuclear egress. PLoS Pathog 2009; 5:e1000275. [PMID: 19165338 PMCID: PMC2625439 DOI: 10.1371/journal.ppat.1000275] [Citation(s) in RCA: 168] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 12/17/2008] [Indexed: 01/19/2023] Open
Abstract
The nuclear lamina is a major obstacle encountered by herpesvirus nucleocapsids in their passage from the nucleus to the cytoplasm (nuclear egress). We found that the human cytomegalovirus (HCMV)-encoded protein kinase UL97, which is required for efficient nuclear egress, phosphorylates the nuclear lamina component lamin A/C in vitro on sites targeted by Cdc2/cyclin-dependent kinase 1, the enzyme that is responsible for breaking down the nuclear lamina during mitosis. Quantitative mass spectrometry analyses, comparing lamin A/C isolated from cells infected with viruses either expressing or lacking UL97 activity, revealed UL97-dependent phosphorylation of lamin A/C on the serine at residue 22 (Ser(22)). Transient treatment of HCMV-infected cells with maribavir, an inhibitor of UL97 kinase activity, reduced lamin A/C phosphorylation by approximately 50%, consistent with UL97 directly phosphorylating lamin A/C during HCMV replication. Phosphorylation of lamin A/C during viral replication was accompanied by changes in the shape of the nucleus, as well as thinning, invaginations, and discrete breaks in the nuclear lamina, all of which required UL97 activity. As Ser(22) is a phosphorylation site of particularly strong relevance for lamin A/C disassembly, our data support a model wherein viral mimicry of a mitotic host cell kinase activity promotes nuclear egress while accommodating viral arrest of the cell cycle.
Collapse
Affiliation(s)
- Sofia Hamirally
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jeremy P. Kamil
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yasmine M. Ndassa-Colday
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alison J. Lin
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Wan Jin Jahng
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Moon-Chang Baek
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sarah Noton
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Laurie A. Silva
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Martha Simpson-Holley
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David M. Knipe
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David E. Golan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Hematology Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jarrod A. Marto
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Donald M. Coen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
42
|
Hume AJ, Kalejta RF. Regulation of the retinoblastoma proteins by the human herpesviruses. Cell Div 2009; 4:1. [PMID: 19146698 PMCID: PMC2636798 DOI: 10.1186/1747-1028-4-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Accepted: 01/15/2009] [Indexed: 01/21/2023] Open
Abstract
Viruses are obligate intracellular parasites that alter the environment of infected cells in order to replicate more efficiently. One way viruses achieve this is by modulating cell cycle progression. The main regulators of progression out of G0, through G1, and into S phase are the members of the retinoblastoma (Rb) family of tumor suppressors. Rb proteins repress the transcription of genes controlled by the E2F transcription factors. Because the expression of E2F-responsive genes is required for cell cycle progression into the S phase, Rb arrests the cell cycle in G0/G1. A number of viral proteins directly target Rb family members for inactivation, presumably to create an environment more hospitable for viral replication. Such viral proteins include the extensively studied oncoproteins E7 (from human papillomavirus), E1A (from adenovirus), and the large T (tumor) antigen (from simian virus 40). Elucidating how these three viral proteins target and inactivate Rb has proven to be an invaluable approach to augment our understanding of both normal cell cycle progression and carcinogenesis. In addition to these proteins, a number of other virally-encoded inactivators of the Rb family have subsequently been identified including a surprising number encoded by human herpesviruses. Here we review how the human herpesviruses modulate Rb function during infection, introduce the individual viral proteins that directly or indirectly target Rb, and speculate about what roles Rb modulation by these proteins may play in viral replication, pathogenesis, and oncogenesis.
Collapse
Affiliation(s)
- Adam J Hume
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI 53706-1596, USA.
| | | |
Collapse
|
43
|
Shin KC, Park CG, Hwang ES, Cha CY. Human cytomegalovirus IE1 protein enhances herpes simplex virus type 1-induced syncytial formation in U373MG cells. J Korean Med Sci 2008; 23:1046-52. [PMID: 19119451 PMCID: PMC2610642 DOI: 10.3346/jkms.2008.23.6.1046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Accepted: 03/12/2008] [Indexed: 12/18/2022] Open
Abstract
Co-infection of herpes simplex virus type 1 (HSV-1) and human cytomegalovirus (HCMV) is not uncommon in immunocompromised hosts. Importantly, organ transplant recipients concurrently infected with HSV-1 and HCMV have a worse clinical outcome than recipients infected with a single virus. However, factors regulating the pathologic response in HSV-1, HCMV co-infected tissues are unclear. We investigated the potential biologic role of HCMV gene product immediate early 1 (IE1) protein in HSV-1-induced syncytial formation in U373MG cells. We utilized a co-infection model by infecting HSV-1 to U373MG cells constitutively expressing HCMV IE1 protein, UMG1-2. Syncytial formation was assessed by enumerating nuclei number per syncytium and number of syncytia. HSV-1-induced syncytial formation was enhanced after 24 hr in UMG1-2 cells compared with U373MG controls. The amplified phenotype in UMG1-2 cells was effectively suppressed by roscovitine in addition to inhibitors of viral replication. This is the first study to provide histological evidence of the contribution of HCMV IE1 protein to enhanced cytopathogenic responses in active HSV-1 infection.
Collapse
Affiliation(s)
- Ki-Chul Shin
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Chung-Gyu Park
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea
| | - Eung-Soo Hwang
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea
| | - Chang-Yon Cha
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, Korea
| |
Collapse
|
44
|
Mercorelli B, Sinigalia E, Loregian A, Palù G. Human cytomegalovirus DNA replication: antiviral targets and drugs. Rev Med Virol 2008; 18:177-210. [PMID: 18027349 DOI: 10.1002/rmv.558] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Human cytomegalovirus (HCMV) infection is associated with severe morbidity and mortality in immunocompromised individuals, in particular transplant recipients and AIDS patients, and is the most frequent congenital viral infection in humans. There are currently five drugs approved for HCMV treatment: ganciclovir and its prodrug valganciclovir, foscarnet, cidofovir and fomivirsen. These drugs have provided a major advance in HCMV disease management, but they suffer from poor bioavailability, significant toxicity and limited effectiveness, mainly due to the development of drug resistance. Fortunately, there are several novel and potentially very effective new compounds which are under pre-clinical and clinical evaluation and may address these limitations. This review focuses on HCMV proteins that are directly or indirectly involved in viral DNA replication and represent already established or potential novel antiviral targets, and describes both currently available drugs and new compounds against such protein targets.
Collapse
Affiliation(s)
- Beatrice Mercorelli
- Department of Histology, Microbiology and Medical Biotechnologies, University of Padua, 35121 Padua, Italy
| | | | | | | |
Collapse
|
45
|
Finn OJ. Immunological weapons acquired early in life win battles with cancer late in life. THE JOURNAL OF IMMUNOLOGY 2008; 181:1589-92. [PMID: 18641292 DOI: 10.4049/jimmunol.181.3.1589] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Olivera J Finn
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| |
Collapse
|
46
|
Cell cycle-independent expression of immediate-early gene 3 results in G1 and G2 arrest in murine cytomegalovirus-infected cells. J Virol 2008; 82:10188-98. [PMID: 18667506 DOI: 10.1128/jvi.01212-08] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The infectious cycle of human cytomegalovirus (HCMV) is intricately linked to the host's cell cycle. Viral gene expression can be initiated only in G(0)/G(1) phase. Once expressed, the immediate-early gene product IE2 prevents cellular DNA synthesis, arresting infected cells with a G(1) DNA content. This function is required for efficient viral replication in vitro. A prerequisite for addressing its in vivo relevance is the characterization of cell cycle-regulatory activities of CMV species for which animal models have been established. Here, we show that murine CMV (MCMV), like HCMV, has a strong antiproliferative capacity and arrests cells in G(1). Unexpectedly, and in contrast to HCMV, MCMV can also block cells that have passed through S phase by arresting them in G(2). Moreover, MCMV can also replicate in G(2) cells. This is made possible by the cell cycle-independent expression of MCMV immediate-early genes. Transfection experiments show that of several MCMV candidate genes, only immediate-early gene 3 (ie3), the homologue of HCMV IE2, exhibits cell cycle arrest activity. Accordingly, an MCMV ie3 deletion mutant has lost the ability to arrest cells in either G(1) or G(2). Thus, despite interspecies variations in the cell cycle dependence of viral gene expression, the central theme of HCMV IE2-induced cell cycle arrest is conserved in the murine counterpart, raising the possibility of studying its physiological relevance at the level of the whole organism.
Collapse
|
47
|
Shen W, Westgard E, Huang L, Ward MD, Osborn JL, Chau NH, Collins L, Marcum B, Koach MA, Bibbs J, Semmes OJ, Kerry JA. Nuclear trafficking of the human cytomegalovirus pp71 (ppUL82) tegument protein. Virology 2008; 376:42-52. [PMID: 18423509 DOI: 10.1016/j.virol.2008.03.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 03/10/2008] [Accepted: 03/11/2008] [Indexed: 01/12/2023]
Abstract
The human cytomegalovirus tegument protein pp71 localizes to the nucleus immediately upon infection, and functions to initiate viral gene expression. Analysis of a series of random insertion mutations revealed that sequences within the mid region (MR) of pp71 are important for localization to the nucleus. Fusion of MR sequences with eGFP revealed that amino acids 94 to 300 were sufficient to target proteins to the nucleus. Random substitution mutagenesis within this domain resulted in two double substitution mutants, pp71P203T/T223M and pp71T228M/L275Q, with a predominantly cytoplasmic localization. Disruption of nuclear targeting resulted in relocalization of the fusion proteins to a distinct perinuclear region. Using tandem mass spectrometry, we determined that threonine 223 can be phosphorylated. Mutation of this residue to a phosphomimetic amino acid resulted in abrogation of nuclear targeting. These results strongly suggest that the intracellular trafficking of pp71 is regulated by phosphorylation.
Collapse
Affiliation(s)
- Weiping Shen
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23507, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Siakallis G, Spandidos DA, Sourvinos G. Herpesviridae and novel inhibitors. Antivir Ther 2008; 14:1051-64. [DOI: 10.3851/imp1467] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
49
|
Abstract
Human cytomegalovirus (HCMV) has evolved numerous strategies to commandeer the host cell for producing viral progeny. The virus manipulates host cell cycle pathways from the early stages of infection to stimulate viral DNA replication at the expense of cellular DNA synthesis. At the same time, cell cycle checkpoints are by-passed, preventing apoptosis and allowing sufficient time for the assembly of infectious virus.
Collapse
Affiliation(s)
- V Sanchez
- Deaprtment of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College Station, TX 77843-1266, USA
| | | |
Collapse
|
50
|
Sanchez V, Mahr JA, Orazio NI, Spector DH. Nuclear export of the human cytomegalovirus tegument protein pp65 requires cyclin-dependent kinase activity and the Crm1 exporter. J Virol 2007; 81:11730-6. [PMID: 17715235 PMCID: PMC2168781 DOI: 10.1128/jvi.02760-06] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Accepted: 08/09/2007] [Indexed: 11/20/2022] Open
Abstract
We have previously shown that treatment of human cytomegalovirus-infected cells with the cyclin-dependent kinase (cdk) inhibitor roscovitine has significant effects on several stages of the virus life cycle depending on the time of addition (V. Sanchez, A. K. McElroy, J. Yen, S. Tamrakar, C. L. Clark, R. A. Schwartz, and D. H. Spector, J. Virol. 78:11219-11232, 2004; V. Sanchez and D. Spector, J. Virol. 80:5886-5896, 2006). In this report, we add to these findings by demonstrating alterations in the phosphorylation and localization of pp65 (UL83) in cells treated with roscovitine. We observed that inhibition of cdk activity causes the retention of pp65 within the nucleus at late times postinfection. At the same time, we observed a change in the phosphorylation pattern of the protein. Interestingly, mutation of potential cdk phosphorylation sites did not affect the ability of pp65 to localize to the nucleus or to relocalize to the cytoplasm late in infection. However, we found that the cytoplasmic accumulation of pp65 late in infection was sensitive to the Crm1 inhibitor leptomycin B.
Collapse
Affiliation(s)
- Veronica Sanchez
- Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College Station, TX 77843, USA
| | | | | | | |
Collapse
|