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HIV-1 Vpr mediates the depletion of the cellular repressor CTIP2 to counteract viral gene silencing. Sci Rep 2019; 9:13154. [PMID: 31511615 PMCID: PMC6739472 DOI: 10.1038/s41598-019-48689-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 08/07/2019] [Indexed: 12/15/2022] Open
Abstract
Mammals have evolved many antiviral factors impacting different steps of the viral life cycle. Associated with chromatin-modifying enzymes, the cellular cofactor CTIP2 contributes to HIV-1 gene silencing in latently infected reservoirs that constitute the major block toward an HIV cure. We report, for the first time, that the virus has developed a strategy to overcome this major transcriptional block. Productive HIV-1 infection results in a Vpr-mediated depletion of CTIP2 in microglial cells and CD4+ T cells, two of the major viral reservoirs. Associated to the Cul4A-DDB1-DCAF1 ubiquitin ligase complex, Vpr promotes CTIP2 degradation via the proteasome pathway in the nuclei of target cells and notably at the latent HIV-1 promoter. Importantly, Vpr targets CTIP2 associated with heterochromatin-promoting enzymes dedicated to HIV-1 gene silencing. Thereby, Vpr reactivates HIV-1 expression in a microglial model of HIV-1 latency. Altogether our results suggest that HIV-1 Vpr mediates the depletion of the cellular repressor CTIP2 to counteract viral gene silencing.
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Zhao RY. Yeast for virus research. MICROBIAL CELL (GRAZ, AUSTRIA) 2017; 4:311-330. [PMID: 29082230 PMCID: PMC5657823 DOI: 10.15698/mic2017.10.592] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/27/2017] [Indexed: 12/25/2022]
Abstract
Budding yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe) are two popular model organisms for virus research. They are natural hosts for viruses as they carry their own indigenous viruses. Both yeasts have been used for studies of plant, animal and human viruses. Many positive sense (+) RNA viruses and some DNA viruses replicate with various levels in yeasts, thus allowing study of those viral activities during viral life cycle. Yeasts are single cell eukaryotic organisms. Hence, many of the fundamental cellular functions such as cell cycle regulation or programed cell death are highly conserved from yeasts to higher eukaryotes. Therefore, they are particularly suited to study the impact of those viral activities on related cellular activities during virus-host interactions. Yeasts present many unique advantages in virus research over high eukaryotes. Yeast cells are easy to maintain in the laboratory with relative short doubling time. They are non-biohazardous, genetically amendable with small genomes that permit genome-wide analysis of virologic and cellular functions. In this review, similarities and differences of these two yeasts are described. Studies of virologic activities such as viral translation, viral replication and genome-wide study of virus-cell interactions in yeasts are highlighted. Impacts of viral proteins on basic cellular functions such as cell cycle regulation and programed cell death are discussed. Potential applications of using yeasts as hosts to carry out functional analysis of small viral genome and to develop high throughput drug screening platform for the discovery of antiviral drugs are presented.
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Affiliation(s)
- Richard Yuqi Zhao
- Department of Pathology, Department of Microbiology and Immunology, Institute of Global Health, and Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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HIV-1 Protease in the Fission Yeast Schizosaccharomyces pombe. PLoS One 2016; 11:e0151286. [PMID: 26982200 PMCID: PMC4794156 DOI: 10.1371/journal.pone.0151286] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 02/25/2016] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND HIV-1 protease (PR) is an essential viral enzyme. Its primary function is to proteolyze the viral Gag-Pol polyprotein for production of viral enzymes and structural proteins and for maturation of infectious viral particles. Increasing evidence suggests that PR cleaves host cellular proteins. However, the nature of PR-host cellular protein interactions is elusive. This study aimed to develop a fission yeast (Schizosaccharomyces pombe) model system and to examine the possible interaction of HIV-1 PR with cellular proteins and its potential impact on cell proliferation and viability. RESULTS A fission yeast strain RE294 was created that carried a single integrated copy of the PR gene in its chromosome. The PR gene was expressed using an inducible nmt1 promoter so that PR-specific effects could be measured. HIV-1 PR from this system cleaved the same indigenous viral p6/MA protein substrate as it does in natural HIV-1 infections. HIV-1 PR expression in fission yeast cells prevented cell proliferation and induced cellular oxidative stress and changes in mitochondrial morphology that led to cell death. Both these PR activities can be prevented by a PR-specific enzymatic inhibitor, indinavir, suggesting that PR-mediated proteolytic activities and cytotoxic effects resulted from enzymatic activities of HIV-1 PR. Through genome-wide screening, a serine/threonine kinase, Hhp2, was identified that suppresses HIV-1 PR-induced protease cleavage and cell death in fission yeast and in mammalian cells, where it prevented PR-induced apoptosis and cleavage of caspase-3 and caspase-8. CONCLUSIONS This is the first report to show that HIV-1 protease is functional as an enzyme in fission yeast, and that it behaves in a similar manner as it does in HIV-1 infection. HIV-1 PR-induced cell death in fission yeast could potentially be used as an endpoint for mechanistic studies, and this system could be used for developing a high-throughput system for drug screenings.
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Cullin E3 ligases and their rewiring by viral factors. Biomolecules 2014; 4:897-930. [PMID: 25314029 PMCID: PMC4279162 DOI: 10.3390/biom4040897] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 08/20/2014] [Accepted: 09/15/2014] [Indexed: 02/06/2023] Open
Abstract
The ability of viruses to subvert host pathways is central in disease pathogenesis. Over the past decade, a critical role for the Ubiquitin Proteasome System (UPS) in counteracting host immune factors during viral infection has emerged. This counteraction is commonly achieved by the expression of viral proteins capable of sequestering host ubiquitin E3 ligases and their regulators. In particular, many viruses hijack members of the Cullin-RING E3 Ligase (CRL) family. Viruses interact in many ways with CRLs in order to impact their ligase activity; one key recurring interaction involves re-directing CRL complexes to degrade host targets that are otherwise not degraded within host cells. Removal of host immune factors by this mechanism creates a more amenable cellular environment for viral propagation. To date, a small number of target host factors have been identified, many of which are degraded via a CRL-proteasome pathway. Substantial effort within the field is ongoing to uncover the identities of further host proteins targeted in this fashion and the underlying mechanisms driving their turnover by the UPS. Elucidation of these targets and mechanisms will provide appealing anti-viral therapeutic opportunities. This review is focused on the many methods used by viruses to perturb host CRLs, focusing on substrate sequestration and viral regulation of E3 activity.
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Fraisier C, Koraka P, Belghazi M, Bakli M, Granjeaud S, Pophillat M, Lim SM, Osterhaus A, Martina B, Camoin L, Almeras L. Kinetic analysis of mouse brain proteome alterations following Chikungunya virus infection before and after appearance of clinical symptoms. PLoS One 2014; 9:e91397. [PMID: 24618821 PMCID: PMC3949995 DOI: 10.1371/journal.pone.0091397] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 02/10/2014] [Indexed: 01/13/2023] Open
Abstract
Recent outbreaks of Chikungunya virus (CHIKV) infection have been characterized by an increasing number of severe cases with atypical manifestations including neurological complications. In parallel, the risk map of CHIKV outbreaks has expanded because of improved vector competence. These features make CHIKV infection a major public health concern that requires a better understanding of the underlying physiopathological processes for the development of antiviral strategies to protect individuals from severe disease. To decipher the mechanisms of CHIKV infection in the nervous system, a kinetic analysis on the host proteome modifications in the brain of CHIKV-infected mice sampled before and after the onset of clinical symptoms was performed. The combination of 2D-DIGE and iTRAQ proteomic approaches, followed by mass spectrometry protein identification revealed 177 significantly differentially expressed proteins. This kinetic analysis revealed a dramatic down-regulation of proteins before the appearance of the clinical symptoms followed by the increased expression of most of these proteins in the acute symptomatic phase. Bioinformatic analyses of the protein datasets enabled the identification of the major biological processes that were altered during the time course of CHIKV infection, such as integrin signaling and cytoskeleton dynamics, endosome machinery and receptor recycling related to virus transport and synapse function, regulation of gene expression, and the ubiquitin-proteasome pathway. These results reveal the putative mechanisms associated with severe CHIKV infection-mediated neurological disease and highlight the potential markers or targets that can be used to develop diagnostic and/or antiviral tools.
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Affiliation(s)
- Christophe Fraisier
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes, UM63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France
| | - Penelope Koraka
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Maya Belghazi
- Aix-Marseille Université, CNRS, CRN2M UMR 7286, Marseille, France
| | - Mahfoud Bakli
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes, UM63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France
| | - Samuel Granjeaud
- CRCM, Marseille Protéomique, Inserm, U1068, Marseille, France
- Aix-Marseille Université, UM 105, Marseille, France
| | - Matthieu Pophillat
- CRCM, Marseille Protéomique, Inserm, U1068, Marseille, France
- Aix-Marseille Université, UM 105, Marseille, France
| | - Stephanie M. Lim
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Albert Osterhaus
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Byron Martina
- Department of Viroscience, Erasmus MC, Rotterdam, The Netherlands
| | - Luc Camoin
- CRCM, Marseille Protéomique, Inserm, U1068, Marseille, France
- Aix-Marseille Université, UM 105, Marseille, France
| | - Lionel Almeras
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes, UM63, CNRS 7278, IRD 198, Inserm 1095, Marseille, France
- Unité de recherche en biologie et épidémiologie parasitaires (URBEP), Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France
- * E-mail:
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Abstract
HIV-1 viral protein R (VpR) is a multifunctional protein that plays specific roles at multiple stages of the HIV-1 viral life cycle and affects anti-HIV functions of the immune cells. VpR is required for efficient viral replication in nondividing cells such as macrophages, and it promotes, to some extent, viral replication in the proliferating target CD4+ T cells. A number of specific activities that may contribute to these effects of VpR have been proposed. In this chapter, we describe two best characterized activities of VpR, nuclear import of the HIV-1 preintegration complex (PIC) and induction of cell cycle G2 arrest, focusing on the methods used for their demonstration.
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Jung J, Byeon IJL, DeLucia M, Koharudin LMI, Ahn J, Gronenborn AM. Binding of HIV-1 Vpr protein to the human homolog of the yeast DNA repair protein RAD23 (hHR23A) requires its xeroderma pigmentosum complementation group C binding (XPCB) domain as well as the ubiquitin-associated 2 (UBA2) domain. J Biol Chem 2013; 289:2577-88. [PMID: 24318982 DOI: 10.1074/jbc.m113.534453] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human homolog of the yeast DNA repair protein RAD23, hHR23A, has been found previously to interact with the human immunodeficiency virus, type 1 accessory protein Vpr. hHR23A is a modular protein containing an N-terminal ubiquitin-like (UBL) domain and two ubiquitin-associated domains (UBA1 and UBA2) separated by a xeroderma pigmentosum complementation group C binding (XPCB) domain. All domains are connected by flexible linkers. hHR23A binds ubiquitinated proteins and acts as a shuttling factor to the proteasome. Here, we show that hHR23A utilizes both the UBA2 and XPCB domains to form a stable complex with Vpr, linking Vpr directly to cellular DNA repair pathways and their probable exploitation by the virus. Detailed structural mapping of the Vpr contacts on hHR23A, by NMR, revealed substantial contact surfaces on the UBA2 and XPCB domains. In addition, Vpr binding disrupts an intramolecular UBL-UBA2 interaction. We also show that Lys-48-linked di-ubiquitin, when binding to UBA1, does not release the bound Vpr from the hHR23A-Vpr complex. Instead, a ternary hHR23A·Vpr·di-Ub(K48) complex is formed, indicating that Vpr does not necessarily abolish hHR23A-mediated shuttling to the proteasome.
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Affiliation(s)
- Jinwon Jung
- From the Department of Structural Biology and Pittsburgh Center for HIV-Host Protein Interactions, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania 15261
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Maudet C, Sourisce A, Dragin L, Lahouassa H, Rain JC, Bouaziz S, Ramirez BC, Margottin-Goguet F. HIV-1 Vpr induces the degradation of ZIP and sZIP, adaptors of the NuRD chromatin remodeling complex, by hijacking DCAF1/VprBP. PLoS One 2013; 8:e77320. [PMID: 24116224 PMCID: PMC3792905 DOI: 10.1371/journal.pone.0077320] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 09/06/2013] [Indexed: 01/02/2023] Open
Abstract
The Vpr protein from type 1 and type 2 Human Immunodeficiency Viruses (HIV-1 and HIV-2) is thought to inactivate several host proteins through the hijacking of the DCAF1 adaptor of the Cul4A ubiquitin ligase. Here, we identified two transcriptional regulators, ZIP and sZIP, as Vpr-binding proteins degraded in the presence of Vpr. ZIP and sZIP have been shown to act through the recruitment of the NuRD chromatin remodeling complex. Strikingly, chromatin is the only cellular fraction where Vpr is present together with Cul4A ubiquitin ligase subunits. Components of the NuRD complex and exogenous ZIP and sZIP were also associated with this fraction. Several lines of evidence indicate that Vpr induces ZIP and sZIP degradation by hijacking DCAF1: (i) Vpr induced a drastic decrease of exogenously expressed ZIP and sZIP in a dose-dependent manner, (ii) this decrease relied on the proteasome activity, (iii) ZIP or sZIP degradation was impaired in the presence of a DCAF1-binding deficient Vpr mutant or when DCAF1 expression was silenced. Vpr-mediated ZIP and sZIP degradation did not correlate with the growth-related Vpr activities, namely G2 arrest and G2 arrest-independent cytotoxicity. Nonetheless, infection with HIV-1 viruses expressing Vpr led to the degradation of the two proteins. Altogether our results highlight the existence of two host transcription factors inactivated by Vpr. The role of Vpr-mediated ZIP and sZIP degradation in the HIV-1 replication cycle remains to be deciphered.
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Affiliation(s)
- Claire Maudet
- Institut National de la Sante et de la recherche Medicale Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR8104, Paris, France
- University Paris Descartes, Paris, France
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Adèle Sourisce
- Institut National de la Sante et de la recherche Medicale Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR8104, Paris, France
- University Paris Descartes, Paris, France
| | - Loïc Dragin
- Institut National de la Sante et de la recherche Medicale Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR8104, Paris, France
- University Paris Descartes, Paris, France
| | - Hichem Lahouassa
- Institut National de la Sante et de la recherche Medicale Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR8104, Paris, France
- University Paris Descartes, Paris, France
| | | | - Serge Bouaziz
- University Paris Descartes, Paris, France
- CNRS UMR8015, Paris, France
| | - Bertha Cécilia Ramirez
- Institut National de la Sante et de la recherche Medicale Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR8104, Paris, France
- University Paris Descartes, Paris, France
| | - Florence Margottin-Goguet
- Institut National de la Sante et de la recherche Medicale Inserm U1016, Institut Cochin, Paris, France
- CNRS UMR8104, Paris, France
- University Paris Descartes, Paris, France
- * E-mail:
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Takeda E, Murakami T, Matsuda G, Murakami H, Zako T, Maeda M, Aida Y. Nuclear exportin receptor CAS regulates the NPI-1-mediated nuclear import of HIV-1 Vpr. PLoS One 2011; 6:e27815. [PMID: 22110766 PMCID: PMC3218035 DOI: 10.1371/journal.pone.0027815] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Accepted: 10/26/2011] [Indexed: 11/24/2022] Open
Abstract
Vpr, an accessory protein of human immunodeficiency virus type 1, is a multifunctional protein that plays an important role in viral replication. We have previously shown that the region between residues 17 and 74 of Vpr (VprN17C74) contained a bona fide nuclear localization signal and it is targeted VprN17C74 to the nuclear envelope and then imported into the nucleus by importin α (Impα) alone. The interaction between Impα and Vpr is important not only for the nuclear import of Vpr but also for HIV-1 replication in macrophages; however, it was unclear whether full-length Vpr enters the nucleus in a manner similar to VprN17C74. This study investigated the nuclear import of full-length Vpr using the three typical Impα isoforms, Rch1, Qip1 and NPI-1, and revealed that full-length Vpr is selectively imported by NPI-1, but not Rch1 and Qip1, after it makes contact with the perinuclear region in digitonin-permeabilized cells. A binding assay using the three Impα isoforms showed that Vpr bound preferentially to the ninth armadillo repeat (ARM) region (which is also essential for the binding of CAS, the export receptor for Impα) in all three isoforms. Comparison of biochemical binding affinities between Vpr and the Impα isoforms using surface plasmon resonance analysis demonstrated almost identical values for the binding of Vpr to the full-length isoforms and to their C-terminal domains. By contrast, the data showed that, in the presence of CAS, Vpr was released from the Vpr/NPI-1 complex but was not released from Rch1 or Qip1. Finally, the NPI-1–mediated nuclear import of Vpr was greatly reduced in semi-intact CAS knocked-down cells and was recovered by the addition of exogenous CAS. This report is the first to show the requirement for and the regulation of CAS in the functioning of the Vpr-Impα complex.
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Affiliation(s)
- Eri Takeda
- Viral Infectious Diseases Unit, RIKEN, Hirosawa, Wako, Saitama, Japan
| | - Tomoyuki Murakami
- Viral Infectious Diseases Unit, RIKEN, Hirosawa, Wako, Saitama, Japan
- Laboratory of Viral Infectious Diseases, Department of Medical Genome Sciences, Graduate School of Frontier Science, The University of Tokyo, Wako, Saitama, Japan
| | - Go Matsuda
- Viral Infectious Diseases Unit, RIKEN, Hirosawa, Wako, Saitama, Japan
| | - Hironobu Murakami
- Viral Infectious Diseases Unit, RIKEN, Hirosawa, Wako, Saitama, Japan
- Japan Foundation for AIDS Prevention, Chiyoda-ku, Tokyo, Japan
| | - Tamotsu Zako
- Bioengineering Laboratory, RIKEN, Hirosawa, Wako, Saitama, Japan
| | - Mizuo Maeda
- Bioengineering Laboratory, RIKEN, Hirosawa, Wako, Saitama, Japan
| | - Yoko Aida
- Viral Infectious Diseases Unit, RIKEN, Hirosawa, Wako, Saitama, Japan
- Laboratory of Viral Infectious Diseases, Department of Medical Genome Sciences, Graduate School of Frontier Science, The University of Tokyo, Wako, Saitama, Japan
- * E-mail:
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Zhao RY, Li G, Bukrinsky MI. Vpr-host interactions during HIV-1 viral life cycle. J Neuroimmune Pharmacol 2011; 6:216-29. [PMID: 21318276 PMCID: PMC5482210 DOI: 10.1007/s11481-011-9261-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Accepted: 01/23/2011] [Indexed: 12/21/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) is a multifunctional viral protein that plays important role at multiple stages of the HIV-1 viral life cycle. Although the molecular mechanisms underlying these activities are subject of ongoing investigations, overall, these activities have been linked to promotion of viral replication and impairment of anti-HIV immunity. Importantly, functional defects of Vpr have been correlated with slow disease progression of HIV-infected patients. Vpr is required for efficient viral replication in non-dividing cells such as macrophages, and it promotes, to some extent, viral replication in proliferating CD4+ T cells. The specific activities of Vpr include modulation of fidelity of viral reverse transcription, nuclear import of the HIV-1 pre-integration complex, transactivation of the HIV-1 LTR promoter, induction of cell cycle G2 arrest and cell death via apoptosis. In this review, we focus on description of the cellular proteins that specifically interact with Vpr and discuss their significance with regard to the known Vpr activities at each step of the viral life cycle in proliferating and non-proliferating cells.
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Affiliation(s)
- Richard Y Zhao
- Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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