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DeCotiis-Mauro J, Han SM, Mello H, Goyeneche C, Marchesini-Tovar G, Jin L, Bellofatto V, Lukac DM. The cellular Notch1 protein promotes KSHV reactivation in an Rta-dependent manner. J Virol 2024; 98:e0078824. [PMID: 38975769 PMCID: PMC11334469 DOI: 10.1128/jvi.00788-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Accepted: 06/05/2024] [Indexed: 07/09/2024] Open
Abstract
The cellular Notch signal transduction pathway is intimately associated with infections by Kaposi's sarcoma-associated herpesvirus (KSHV) and other gamma-herpesviruses. RBP-Jk, the cellular DNA binding component of the canonical Notch pathway, is the key Notch downstream effector protein in virus-infected and uninfected animal cells. Reactivation of KSHV from latency requires the viral lytic switch protein, Rta, to form complexes with RBP-Jk on numerous sites within the viral DNA. Constitutive Notch activity is essential for KSHV pathophysiology in models of Kaposi's sarcoma (KS) and Primary Effusion Lymphoma (PEL), and we demonstrate that Notch1 is also constitutively active in infected Vero cells. Although the KSHV genome contains >100 RBP-Jk DNA motifs, we show that none of the four isoforms of activated Notch can productively reactivate the virus from latency in a highly quantitative trans-complementing reporter virus system. Nevertheless, Notch contributed positively to reactivation because broad inhibition of Notch1-4 with gamma-secretase inhibitor (GSI) or expression of dominant negative mastermind-like1 (dnMAML1) coactivators severely reduced production of infectious KSHV from Vero cells. Reduction of KSHV production is associated with gene-specific reduction of viral transcription in both Vero and PEL cells. Specific inhibition of Notch1 by siRNA partially reduces the production of infectious KSHV, and NICD1 forms promoter-specific complexes with viral DNA during reactivation. We conclude that constitutive Notch activity is required for the robust production of infectious KSHV, and our results implicate activated Notch1 as a pro-viral member of a MAML1/RBP-Jk/DNA complex during viral reactivation. IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) manipulates the host cell oncogenic Notch signaling pathway for viral reactivation from latency and cell pathogenesis. KSHV reactivation requires that the viral protein Rta functionally interacts with RBP-Jk, the DNA-binding component of the Notch pathway, and with promoter DNA to drive transcription of productive cycle genes. We show that the Notch pathway is constitutively active during KSHV reactivation and is essential for robust production of infectious virus progeny. Inhibiting Notch during reactivation reduces the expression of specific viral genes yet does not affect the growth of the host cells. Although Notch cannot reactivate KSHV alone, the requisite expression of Rta reveals a previously unappreciated role for Notch in reactivation. We propose that activated Notch cooperates with Rta in a promoter-specific manner that is partially programmed by Rta's ability to redistribute RBP-Jk DNA binding to the virus during reactivation.
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Affiliation(s)
- Jennifer DeCotiis-Mauro
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
- School of Graduate Studies, Rutgers Biomedical and Health Sciences, Health Science Campus at Newark, Rutgers University, Newark, New Jersey, USA
| | - Sun M. Han
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
- School of Graduate Studies, Rutgers Biomedical and Health Sciences, Health Science Campus at Newark, Rutgers University, Newark, New Jersey, USA
| | - Helena Mello
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
- School of Graduate Studies, Rutgers Biomedical and Health Sciences, Health Science Campus at Newark, Rutgers University, Newark, New Jersey, USA
| | - Corey Goyeneche
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
- School of Graduate Studies, Rutgers Biomedical and Health Sciences, Health Science Campus at Newark, Rutgers University, Newark, New Jersey, USA
| | - Giuseppina Marchesini-Tovar
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
- School of Graduate Studies, Rutgers Biomedical and Health Sciences, Health Science Campus at Newark, Rutgers University, Newark, New Jersey, USA
| | - Lianhua Jin
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
- School of Graduate Studies, Rutgers Biomedical and Health Sciences, Health Science Campus at Newark, Rutgers University, Newark, New Jersey, USA
| | - Vivian Bellofatto
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
- School of Graduate Studies, Rutgers Biomedical and Health Sciences, Health Science Campus at Newark, Rutgers University, Newark, New Jersey, USA
| | - David M. Lukac
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey, USA
- School of Graduate Studies, Rutgers Biomedical and Health Sciences, Health Science Campus at Newark, Rutgers University, Newark, New Jersey, USA
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Roy Chowdhury N, Gurevich V, Shamay M. KSHV genome harbors both constitutive and lytically induced enhancers. J Virol 2024; 98:e0017924. [PMID: 38695538 PMCID: PMC11237633 DOI: 10.1128/jvi.00179-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/03/2024] [Indexed: 06/14/2024] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) belongs to the gamma-herpesvirus family and is a well-known human oncogenic virus. In infected cells, the viral genome of 165 kbp is circular DNA wrapped in chromatin. The tight control of gene expression is critical for latency, the transition into the lytic phase, and the development of viral-associated malignancies. Distal cis-regulatory elements, such as enhancers and silencers, can regulate gene expression in a position- and orientation-independent manner. Open chromatin is another characteristic feature of enhancers. To systematically search for enhancers, we cloned all the open chromatin regions in the KSHV genome downstream of the luciferase gene and tested their enhancer activity in infected and uninfected cells. A silencer was detected upstream of the latency-associated nuclear antigen promoter. Two constitutive enhancers were identified in the K12p-OriLyt-R and ORF29 Intron regions, where ORF29 Intron is a tissue-specific enhancer. The following promoters: OriLyt-L, PANp, ALTp, and the terminal repeats (TRs) acted as lytically induced enhancers. The expression of the replication and transcription activator (RTA), the master regulator of the lytic cycle, was sufficient to induce the activity of lytic enhancers in uninfected cells. We propose that the TRs that span about 24 kbp region serve as a "viral super-enhancer" that integrates the repressive effect of the latency-associated nuclear antigen (LANA) with the activating effect of RTA. Utilizing CRISPR activation and interference techniques, we determined the connections between these enhancers and their regulated genes. The silencer and enhancers described here provide an additional layer to the complex gene regulation of herpesviruses.IMPORTANCEIn this study, we performed a systematic functional assay to identify cis-regulatory elements within the genome of the oncogenic herpesvirus, Kaposi's sarcoma-associated herpesvirus (KSHV). Similar to other herpesviruses, KSHV presents both latent and lytic phases. Therefore, our assays were performed in uninfected cells, during latent infection, and under lytic conditions. We identified two constitutive enhancers, one of which seems to be a tissue-specific enhancer. In addition, four lytically induced enhancers, which are all responsive to the replication and transcription activator (RTA), were identified. Furthermore, a silencer was identified between the major latency promoter and the lytic gene locus. Utilizing CRISPR activation and interference techniques, we determined the connections between these enhancers and their regulated genes. The terminal repeats, spanning a region of about 24 kbp, seem like a "viral super-enhancer" that integrates the repressive effect of the latency-associated nuclear antigen (LANA) with the activating effect of RTA to regulate latency to lytic transition.
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Affiliation(s)
- Nilabja Roy Chowdhury
- Daniella Lee Casper Laboratory in Viral Oncology, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Vyacheslav Gurevich
- Daniella Lee Casper Laboratory in Viral Oncology, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Meir Shamay
- Daniella Lee Casper Laboratory in Viral Oncology, Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
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Jang SJ, Atyeo N, Mietzsch M, Chae MY, McKenna R, Toth Z, Papp B. Genome-Wide Transcriptional Roles of KSHV Viral Interferon Regulatory Factors in Oral Epithelial Cells. Viruses 2024; 16:846. [PMID: 38932139 PMCID: PMC11209080 DOI: 10.3390/v16060846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 05/17/2024] [Accepted: 05/21/2024] [Indexed: 06/28/2024] Open
Abstract
The viral interferon regulatory factors (vIRFs) of KSHV are known to dysregulate cell signaling pathways to promote viral oncogenesis and to block antiviral immune responses to facilitate infection. However, it remains unknown to what extent each vIRF plays a role in gene regulation. To address this, we performed a comparative analysis of the protein structures and gene regulation of the four vIRFs. Our structure prediction analysis revealed that despite their low amino acid sequence similarity, vIRFs exhibit high structural homology in both their DNA-binding domain (DBD) and IRF association domain. However, despite this shared structural homology, we demonstrate that each vIRF regulates a distinct set of KSHV gene promoters and human genes in epithelial cells. We also found that the DBD of vIRF1 is essential in regulating the expression of its target genes. We propose that the structurally similar vIRFs evolved to possess specialized transcriptional functions to regulate specific genes.
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Affiliation(s)
- Seung Jin Jang
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL 32610, USA
| | - Natalie Atyeo
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL 32610, USA
| | - Mario Mietzsch
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1200 Newell Drive, Gainesville, FL 32610, USA
| | - Min Y. Chae
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL 32610, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1200 Newell Drive, Gainesville, FL 32610, USA
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL 32610, USA
- UF Genetics Institute, Gainesville, FL 32610, USA
- UF Health Cancer Center, Gainesville, FL 32610, USA
| | - Bernadett Papp
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL 32610, USA
- UF Genetics Institute, Gainesville, FL 32610, USA
- UF Health Cancer Center, Gainesville, FL 32610, USA
- UF Center for Orphaned Autoimmune Disorders, Gainesville, FL 32610, USA
- UF Informatics Institute, Gainesville, FL 32610, USA
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Izumiya Y, Algalil A, Espera JM, Miura H, Izumiya C, Inagaki T, Kumar A. Kaposi's sarcoma-associated herpesvirus terminal repeat regulates inducible lytic gene promoters. J Virol 2024; 98:e0138623. [PMID: 38240593 PMCID: PMC10878276 DOI: 10.1128/jvi.01386-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/02/2024] [Indexed: 02/21/2024] Open
Abstract
The Kaposi's sarcoma-associated herpesvirus (KSHV) genome consists of an approximately 140-kb unique coding region flanked by 30-40 copies of a 0.8-kb terminal repeat (TR) sequence. A gene enhancer recruits transcription-related enzymes by having arrays of transcription factor binding sites. Here, we show that KSHV TR possesses transcription regulatory function with latency-associated nuclear antigen (LANA). Cleavage under targets and release using nuclease demonstrated that TR fragments were occupied by LANA-interacting histone-modifying enzymes in naturally infected cells. The TR was enriched with histone H3K27 acetylation (H3K27Ac) and H3K4 tri-methylation (H3K4me3) modifications and also expressed nascent RNAs. The sites of H3K27Ac and H3K4me3 modifications were also conserved in the KSHV unique region among naturally infected primary effusion lymphoma cells. KSHV origin of lytic replication (Ori-Lyt) showed similar protein and histone modification occupancies with that of TR. In the Ori-Lyt region, the LANA and LANA-interacting proteins colocalized with an H3K27Ac-modified nucleosome along with paused RNA polymerase II. The KSHV transactivator KSHV replication and transcription activator (K-Rta) recruitment sites franked the LANA-bound nucleosome, and reactivation evicted the LANA-bound nucleosome. Including TR fragments in reporter plasmid enhanced inducible viral gene promoter activities independent of the orientations. In the presence of TR in reporter plasmids, K-Rta transactivation was drastically increased, while LANA acquired the promoter repression function. KSHV TR, therefore, functions as an enhancer for KSHV inducible genes. However, in contrast to cellular enhancers bound by multiple transcription factors, perhaps the KSHV enhancer is predominantly regulated by the LANA nuclear body.IMPORTANCEEnhancers are a crucial regulator of differential gene expression programs. Enhancers are the cis-regulatory sequences determining target genes' spatiotemporal and quantitative expression. Here, we show that Kaposi's sarcoma-associated herpesvirus (KSHV) terminal repeats fulfill the enhancer definition for KSHV inducible gene promoters. The KSHV enhancer is occupied by latency-associated nuclear antigen (LANA) and its interacting proteins, such as CHD4. Neighboring terminal repeat (TR) fragments to lytic gene promoters drastically enhanced KSHV replication and transcription activator and LANA transcription regulatory functions. This study, thus, proposes a new latency-lytic switch model in which TR accessibility to the KSHV gene promoters regulates viral inducible gene expression.
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Affiliation(s)
- Yoshihiro Izumiya
- Department of Dermatology, School of Medicine, University of California Davis, Sacramento, California, USA
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California Davis, Sacramento, California, USA
| | - Adhraa Algalil
- Department of Dermatology, School of Medicine, University of California Davis, Sacramento, California, USA
- Midwestern University College of Dental Medicine, Glendale, Arizona, USA
| | - Jonna M. Espera
- Department of Dermatology, School of Medicine, University of California Davis, Sacramento, California, USA
| | - Hiroki Miura
- Department of Dermatology, School of Medicine, University of California Davis, Sacramento, California, USA
| | - Chie Izumiya
- Department of Dermatology, School of Medicine, University of California Davis, Sacramento, California, USA
| | - Tomoki Inagaki
- Department of Dermatology, School of Medicine, University of California Davis, Sacramento, California, USA
| | - Ashish Kumar
- Department of Dermatology, School of Medicine, University of California Davis, Sacramento, California, USA
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Prazsák I, Tombácz D, Fülöp Á, Torma G, Gulyás G, Dörmő Á, Kakuk B, McKenzie Spires L, Toth Z, Boldogkői Z. KSHV 3.0: a state-of-the-art annotation of the Kaposi's sarcoma-associated herpesvirus transcriptome using cross-platform sequencing. mSystems 2024; 9:e0100723. [PMID: 38206015 PMCID: PMC10878076 DOI: 10.1128/msystems.01007-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 12/11/2023] [Indexed: 01/12/2024] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is a large, oncogenic DNA virus belonging to the gammaherpesvirus subfamily. KSHV has been extensively studied with various high-throughput RNA-sequencing approaches to map the transcription start and end sites, the splice junctions, and the translation initiation sites. Despite these efforts, the comprehensive annotation of the viral transcriptome remains incomplete. In the present study, we generated a long-read sequencing data set of the lytic and latent KSHV transcriptome using native RNA and direct cDNA-sequencing methods. This was supplemented with Cap Analysis of Gene Expression sequencing based on a short-read platform. We also utilized data sets from previous publications for our analysis. As a result of this combined approach, we have identified a number of novel viral transcripts and RNA isoforms and have either corroborated or improved the annotation of previously identified viral RNA molecules, thereby notably enhancing our comprehension of the transcriptomic architecture of the KSHV genome. We also evaluated the coding capability of transcripts previously thought to be non-coding by integrating our data on the viral transcripts with translatomic information from other publications.IMPORTANCEDeciphering the viral transcriptome of Kaposi's sarcoma-associated herpesvirus is of great importance because we can gain insight into the molecular mechanism of viral replication and pathogenesis, which can help develop potential targets for antiviral interventions. Specifically, the identification of substantial transcriptional overlaps by this work suggests the existence of a genome-wide interference between transcriptional machineries. This finding indicates the presence of a novel regulatory layer, potentially controlling the expression of viral genes.
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Affiliation(s)
- István Prazsák
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Dóra Tombácz
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Ádám Fülöp
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Gábor Torma
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Gábor Gulyás
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Ákos Dörmő
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Balázs Kakuk
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Lauren McKenzie Spires
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Zsolt Boldogkői
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
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Li S, Wang M, Van Sciver N, Szymula A, Tumuluri VS, George A, Ramachandran A, Raina K, Costa CN, Zhao B, Kazemian M, Simas JP, Kaye KM. Kaposi's sarcoma herpesvirus latency-associated nuclear antigen broadly regulates viral gene expression and is essential for lytic infection. PLoS Pathog 2024; 20:e1011907. [PMID: 38232124 PMCID: PMC10793894 DOI: 10.1371/journal.ppat.1011907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 12/18/2023] [Indexed: 01/19/2024] Open
Abstract
Kaposi's sarcoma herpesvirus (KSHV) is a leading cause of malignancy in AIDS and current therapies are limited. Like all herpesviruses, KSHV infection can be latent or lytic. KSHV latency-associated nuclear antigen (LANA) is essential for viral genome persistence during latent infection. LANA also maintains latency by antagonizing expression and function of the KSHV lytic switch protein, RTA. Here, we find LANA null KSHV is not capable of lytic replication, indicating a requirement for LANA. While LANA promoted both lytic and latent gene expression in cells partially permissive for lytic infection, it repressed expression in non-permissive cells. Importantly, forced RTA expression in non-permissive cells led to induction of lytic infection and LANA switched to promote, rather than repress, most lytic viral gene expression. When basal viral gene expression levels were high, LANA promoted expression, but repressed expression at low basal levels unless RTA expression was forcibly induced. LANA's effects were broad, but virus gene specific, extending to an engineered, recombinant viral GFP under control of host EF1α promoter, but not to host EF1α. Together, these results demonstrate that, in addition to its essential role in genome maintenance, LANA broadly regulates viral gene expression, and is required for high levels of lytic gene expression during lytic infection. Strategies that target LANA are expected to abolish KSHV infection.
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Affiliation(s)
- Shijun Li
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mengbo Wang
- Department of Computer Science, Purdue University, West Lafayette, Indiana
| | - Nicholas Van Sciver
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Agnieszka Szymula
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Vinayak Sadasivam Tumuluri
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Athira George
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Akshaya Ramachandran
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Komal Raina
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Catarina N. Costa
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, Lisboa, Portugal
- Universidade Católica Portuguesa, Católica Medical School, Católica Biomedical Research, Palma de Cima, Portugal
| | - Bo Zhao
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Majid Kazemian
- Department of Computer Science, Purdue University, West Lafayette, Indiana
- Department of Biochemistry, Purdue University, West Lafayette, Indiana
| | - J. Pedro Simas
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, Lisboa, Portugal
- Universidade Católica Portuguesa, Católica Medical School, Católica Biomedical Research, Palma de Cima, Portugal
| | - Kenneth M. Kaye
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
- Broad Institute of Harvard University and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
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Spires LM, Wind E, Papp B, Toth Z. KSHV RTA utilizes the host E3 ubiquitin ligase complex RNF20/40 to drive lytic reactivation. J Virol 2023; 97:e0138923. [PMID: 37888983 PMCID: PMC10688343 DOI: 10.1128/jvi.01389-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 09/20/2023] [Indexed: 10/28/2023] Open
Abstract
IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is a cancer-causing human herpesvirus that establishes a persistent infection in humans. The lytic viral cycle plays a crucial part in lifelong infection as it is involved in the viral dissemination. The master regulator of the KSHV lytic replication cycle is the viral replication and transcription activator (RTA) protein, which is necessary and sufficient to push the virus from latency into the lytic phase. Thus, the identification of host factors utilized by RTA for controlling the lytic cycle can help to find novel targets that could be used for the development of antiviral therapies against KSHV. Using a proteomics approach, we have identified a novel interaction between RTA and the cellular E3 ubiquitin ligase complex RNF20/40, which we have shown to be necessary for promoting RTA-induced KSHV lytic cycle.
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Affiliation(s)
- Lauren McKenzie Spires
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Eleanor Wind
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Bernadett Papp
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- UF Genetics Institute, Gainesville, Florida, USA
- UF Health Cancer Center, Gainesville, Florida, USA
- UF Center for Orphaned Autoimmune Disorders, Gainesville, Florida, USA
- UF Informatics Institute, Gainesville, Florida, USA
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- UF Genetics Institute, Gainesville, Florida, USA
- UF Health Cancer Center, Gainesville, Florida, USA
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8
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Srivastava A, Srivastava A, Singh RK. Insight into the Epigenetics of Kaposi's Sarcoma-Associated Herpesvirus. Int J Mol Sci 2023; 24:14955. [PMID: 37834404 PMCID: PMC10573522 DOI: 10.3390/ijms241914955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/25/2023] [Accepted: 07/28/2023] [Indexed: 10/15/2023] Open
Abstract
Epigenetic reprogramming represents a series of essential events during many cellular processes including oncogenesis. The genome of Kaposi's sarcoma-associated herpesvirus (KSHV), an oncogenic herpesvirus, is predetermined for a well-orchestrated epigenetic reprogramming once it enters into the host cell. The initial epigenetic reprogramming of the KSHV genome allows restricted expression of encoded genes and helps to hide from host immune recognition. Infection with KSHV is associated with Kaposi's sarcoma, multicentric Castleman's disease, KSHV inflammatory cytokine syndrome, and primary effusion lymphoma. The major epigenetic modifications associated with KSHV can be labeled under three broad categories: DNA methylation, histone modifications, and the role of noncoding RNAs. These epigenetic modifications significantly contribute toward the latent-lytic switch of the KSHV lifecycle. This review gives a brief account of the major epigenetic modifications affiliated with the KSHV genome in infected cells and their impact on pathogenesis.
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Affiliation(s)
- Anusha Srivastava
- Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
| | - Ankit Srivastava
- Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
| | - Rajnish Kumar Singh
- Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India
- Faculty of Medical Sciences, Charotar University of Science and Technology, Changa 388421, Gujarat, India
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9
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Torma G, Tombácz D, Csabai Z, Almsarrhad IAA, Nagy GÁ, Kakuk B, Gulyás G, Spires LM, Gupta I, Fülöp Á, Dörmő Á, Prazsák I, Mizik M, Dani VÉ, Csányi V, Harangozó Á, Zádori Z, Toth Z, Boldogkői Z. Identification of herpesvirus transcripts from genomic regions around the replication origins. Sci Rep 2023; 13:16395. [PMID: 37773348 PMCID: PMC10541914 DOI: 10.1038/s41598-023-43344-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 09/22/2023] [Indexed: 10/01/2023] Open
Abstract
Long-read sequencing (LRS) techniques enable the identification of full-length RNA molecules in a single run eliminating the need for additional assembly steps. LRS research has exposed unanticipated transcriptomic complexity in various organisms, including viruses. Herpesviruses are known to produce a range of transcripts, either close to or overlapping replication origins (Oris) and neighboring genes related to transcription or replication, which possess confirmed or potential regulatory roles. In our research, we employed both new and previously published LRS and short-read sequencing datasets to uncover additional Ori-proximal transcripts in nine herpesviruses from all three subfamilies (alpha, beta and gamma). We discovered novel long non-coding RNAs, as well as splice and length isoforms of mRNAs. Moreover, our analysis uncovered an intricate network of transcriptional overlaps within the examined genomic regions. We demonstrated that herpesviruses display distinct patterns of transcriptional overlaps in the vicinity of or at the Oris. Our findings suggest the existence of a 'super regulatory center' in the genome of alphaherpesviruses that governs the initiation of both DNA replication and global transcription through multilayered interactions among the molecular machineries.
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Affiliation(s)
- Gábor Torma
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Dóra Tombácz
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
- MTA -SZTE Lendület GeMiNI Research Group, University of Szeged, Szeged, Hungary
| | - Zsolt Csabai
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
- MTA -SZTE Lendület GeMiNI Research Group, University of Szeged, Szeged, Hungary
| | - Islam A A Almsarrhad
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Gergely Ármin Nagy
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Balázs Kakuk
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
- MTA -SZTE Lendület GeMiNI Research Group, University of Szeged, Szeged, Hungary
| | - Gábor Gulyás
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
- MTA -SZTE Lendület GeMiNI Research Group, University of Szeged, Szeged, Hungary
| | - Lauren McKenzie Spires
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Ishaan Gupta
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi, India
| | - Ádám Fülöp
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Ákos Dörmő
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
- MTA -SZTE Lendület GeMiNI Research Group, University of Szeged, Szeged, Hungary
| | - István Prazsák
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
- MTA -SZTE Lendület GeMiNI Research Group, University of Szeged, Szeged, Hungary
| | - Máté Mizik
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Virág Éva Dani
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Viktor Csányi
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Ákos Harangozó
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Zoltán Zádori
- HUN-REN Veterinary Medical Research Institute HU, Budapest, Hungary
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Zsolt Boldogkői
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary.
- MTA -SZTE Lendület GeMiNI Research Group, University of Szeged, Szeged, Hungary.
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10
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Oswald J, Constantine M, Adegbuyi A, Omorogbe E, Dellomo AJ, Ehrlich ES. E3 Ubiquitin Ligases in Gammaherpesviruses and HIV: A Review of Virus Adaptation and Exploitation. Viruses 2023; 15:1935. [PMID: 37766341 PMCID: PMC10535929 DOI: 10.3390/v15091935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/10/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
For productive infection and replication to occur, viruses must control cellular machinery and counteract restriction factors and antiviral proteins. Viruses can accomplish this, in part, via the regulation of cellular gene expression and post-transcriptional and post-translational control. Many viruses co-opt and counteract cellular processes via modulation of the host post-translational modification machinery and encoding or hijacking kinases, SUMO ligases, deubiquitinases, and ubiquitin ligases, in addition to other modifiers. In this review, we focus on three oncoviruses, Epstein-Barr virus (EBV), Kaposi's sarcoma herpesvirus (KSHV), and human immunodeficiency virus (HIV) and their interactions with the ubiquitin-proteasome system via viral-encoded or cellular E3 ubiquitin ligase activity.
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Affiliation(s)
| | | | | | | | | | - Elana S. Ehrlich
- Department of Biological Sciences, Towson University, Towson, MD 21252, USA
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11
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Thiruvengadam R, Kim JH. Therapeutic strategy for oncovirus-mediated oral cancer: A comprehensive review. Biomed Pharmacother 2023; 165:115035. [PMID: 37364477 DOI: 10.1016/j.biopha.2023.115035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 06/02/2023] [Accepted: 06/20/2023] [Indexed: 06/28/2023] Open
Abstract
Oral cancer is a neoplastic disorder of the oral cavities, including the lips, tongue, buccal mucosa, and lower and upper gums. Oral cancer assessment entails a multistep process that requires deep knowledge of the molecular networks involved in its progression and development. Preventive measures including public awareness of risk factors and improving public behaviors are necessary, and screening techniques should be encouraged to enable early detection of malignant lesions. Herpes simplex virus (HSV), human papillomavirus (HPV), Epstein-Barr virus (EBV), and Kaposi sarcoma-associated herpesvirus (KSHV) are associated with other premalignant and carcinogenic conditions leading to oral cancer. Oncogenic viruses induce chromosomal rearrangements; activate signal transduction pathways via growth factor receptors, cytoplasmic protein kinases, and DNA binding transcription factors; modulate cell cycle proteins, and inhibit apoptotic pathways. In this review, we present an up-to-date overview on the use of nanomaterials for regulating viral proteins and oral cancer as well as the role of phytocompounds on oral cancer. The targets linking oncoviral proteins and oral carcinogenesis were also discussed.
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Affiliation(s)
- Rekha Thiruvengadam
- Department of Integrative Bioscience & Biotechnology, Sejong University, Seoul 05006, Republic of Korea
| | - Jin Hee Kim
- Department of Integrative Bioscience & Biotechnology, Sejong University, Seoul 05006, Republic of Korea.
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12
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Manners O, Baquero-Perez B, Mottram TJ, Yonchev ID, Trevelyan CJ, Harper KL, Menezes S, Patterson MR, Macdonald A, Wilson SA, Aspden JL, Whitehouse A. m 6A Regulates the Stability of Cellular Transcripts Required for Efficient KSHV Lytic Replication. Viruses 2023; 15:1381. [PMID: 37376680 DOI: 10.3390/v15061381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 06/09/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
The epitranscriptomic modification N6-methyladenosine (m6A) is a ubiquitous feature of the mammalian transcriptome. It modulates mRNA fate and dynamics to exert regulatory control over numerous cellular processes and disease pathways, including viral infection. Kaposi's sarcoma-associated herpesvirus (KSHV) reactivation from the latent phase leads to the redistribution of m6A topology upon both viral and cellular mRNAs within infected cells. Here we investigate the role of m6A in cellular transcripts upregulated during KSHV lytic replication. Our results show that m6A is crucial for the stability of the GPRC5A mRNA, whose expression is induced by the KSHV latent-lytic switch master regulator, the replication and transcription activator (RTA) protein. Moreover, we demonstrate that GPRC5A is essential for efficient KSHV lytic replication by directly regulating NFκB signalling. Overall, this work highlights the central importance of m6A in modulating cellular gene expression to influence viral infection.
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Affiliation(s)
- Oliver Manners
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Belinda Baquero-Perez
- Molecular Virology Unit, Department of Medicine and Life Sciences, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Timothy J Mottram
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Ivaylo D Yonchev
- Sheffield Institute for Nucleic Acids, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Christopher J Trevelyan
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Katherine L Harper
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Sarah Menezes
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Molly R Patterson
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Andrew Macdonald
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Stuart A Wilson
- Sheffield Institute for Nucleic Acids, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Julie L Aspden
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
- LeedsOmics, University of Leeds, Leeds LS2 9JT, UK
| | - Adrian Whitehouse
- School of Molecular and Cellular Biology, Faculty of Biological Sciences and Astbury Centre of Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
- Department of Biochemistry and Microbiology, Rhodes University, Grahamstown 6140, South Africa
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13
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Atyeo N, Chae MY, Toth Z, Sharma A, Papp B. Kaposi's Sarcoma-Associated Herpesvirus Immediate Early Proteins Trigger FOXQ1 Expression in Oral Epithelial Cells, Engaging in a Novel Lytic Cycle-Sustaining Positive Feedback Loop. J Virol 2023; 97:e0169622. [PMID: 36815831 PMCID: PMC10062149 DOI: 10.1128/jvi.01696-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 02/02/2023] [Indexed: 02/24/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic gammaherpesvirus that can replicate in oral epithelial cells to promote viral transmission via saliva. To identify novel regulators of KSHV oral infection, we performed a transcriptome analysis of KSHV-infected primary human gingival epithelial (HGEP) cells, which identified the gene coding for the host transcription factor FOXQ1 as the top induced host gene. FOXQ1 is nearly undetectable in uninfected HGEP and telomerase-immortalized gingival keratinocytes (TIGK) cells but is highly expressed within hours of KSHV infection. We found that while the FOXQ1 promoter lacks activating histone acetylation marks in uninfected oral epithelial cells, these marks accumulate in the FOXQ1 promoter in infected cells, revealing a rapid epigenetic reprogramming event. To evaluate FOXQ1 function, we depleted FOXQ1 in KSHV-infected TIGK cells, which resulted in reduced accumulation of KSHV lytic proteins and viral DNA over the course of 4 days of infection, uncovering a novel lytic cycle-sustaining role of FOXQ1. A screen of KSHV lytic proteins demonstrated that the immediate early proteins ORF45 and replication and transcription activator (RTA) were both sufficient for FOXQ1 induction in oral epithelial cells, indicating active involvement of incoming and rapidly expressed factors in altering host gene expression. ORF45 is known to sustain extracellular signal-regulated kinase (ERK) p90 ribosomal s6 kinase (RSK) pathway activity to promote lytic infection. We found that an ORF45 mutant lacking RSK activation function failed to induce FOXQ1 in TIGK cells, revealing that ORF45 uses a shared mechanism to rapidly induce both host and viral genes to sustain lytic infection in oral epithelial cells. IMPORTANCE The oral cavity is a primary site of initial contact and entry for many viruses. Viral replication in the oral epithelium promotes viral shedding in saliva, allowing interpersonal transmission, as well as spread to other cell types, where chronic infection can be established. Understanding the regulation of KSHV infection in the oral epithelium would allow for the design of universal strategies to target the first stage of viral infection, thereby halting systemic viral pathogenesis. Overall, we uncover a novel positive feedback loop in which immediate early KSHV factors drive rapid host reprogramming of oral epithelial cells to sustain the lytic cycle in the oral cavity.
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Affiliation(s)
- Natalie Atyeo
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Min Young Chae
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- Genetics Institute, University of Florida, Gainesville, Florida, USA
- Health Cancer Center, University of Florida, Gainesville, Florida, USA
| | - Aria Sharma
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Bernadett Papp
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- Genetics Institute, University of Florida, Gainesville, Florida, USA
- Health Cancer Center, University of Florida, Gainesville, Florida, USA
- Informatics Institute, University of Florida, Gainesville, Florida, USA
- Center for Orphaned Autoimmune Disorders, University of Florida, Gainesville, Florida, USA
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14
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Combs LR, Combs J, McKenna R, Toth Z. Protein Degradation by Gammaherpesvirus RTAs: More Than Just Viral Transactivators. Viruses 2023; 15:730. [PMID: 36992439 PMCID: PMC10055789 DOI: 10.3390/v15030730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/09/2023] [Accepted: 03/10/2023] [Indexed: 03/18/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is a member of the Gammaherpesvirus subfamily that encodes several viral proteins with intrinsic E3 ubiquitin ligase activity or the ability to hijack host E3 ubiquitin ligases to modulate the host's immune response and to support the viral life cycle. This review focuses specifically on how the immediate-early KSHV protein RTA (replication and transcription activator) hijacks the host's ubiquitin-proteasome pathway (UPP) to target cellular and viral factors for protein degradation to allow for robust lytic reactivation. Notably, RTA's targets are either potent transcription repressors or they are activators of the innate and adaptive immune response, which block the lytic cycle of the virus. This review mainly focuses on what is currently known about the role of the E3 ubiquitin ligase activity of KSHV RTA in the regulation of the KSHV life cycle, but we will also discuss the potential role of other gammaherpesviral RTA homologs in UPP-mediated protein degradation.
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Affiliation(s)
- Lauren R. Combs
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL 32610, USA
| | - Jacob Combs
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1200 Newell Drive, Gainesville, FL 32610, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, 1200 Newell Drive, Gainesville, FL 32610, USA
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL 32610, USA
- UF Genetics Institute, Gainesville, FL 32610, USA
- UF Health Cancer Center, Gainesville, FL 32610, USA
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15
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Abstract
Eukaryotic genomes are structurally organized via the formation of multiple loops that create gene expression regulatory units called topologically associating domains (TADs). Here we revealed the KSHV TAD structure at 500 bp resolution and constructed a 3D KSHV genomic structural model with 2 kb binning. The latent KSHV genome formed very similar genomic architectures in three different naturally infected PEL cell lines and in an experimentally infected epithelial cell line. The majority of the TAD boundaries were occupied by structural maintenance of chromosomes (SMC1) cohesin complex and CCCTC-binding factor (CTCF), and the KSHV transactivator was recruited to those sites during reactivation. Triggering KSHV gene expression decreased prewired genomic loops within the regulatory unit, while contacts extending outside of regulatory borders increased, leading to formation of a larger regulatory unit with a shift from repressive to active compartments (B to A). The 3D genomic structural model proposes that the immediate early promoter region is localized on the periphery of the 3D viral genome during latency, while highly inducible noncoding RNA regions moved toward the inner space of the structure, resembling the configuration of a "bird cage" during reactivation. The compartment-like properties of viral episomal chromatin structure and its reorganization during the transition from latency may help facilitate viral gene transcription. IMPORTANCE The 3D architecture of chromatin allows for efficient arrangement, expression, and replication of genetic material. The genomes of all organisms studied to date have been found to be organized through some form of tiered domain structures. However, the architectural framework of the genomes of large double-stranded DNA viruses such as the herpesvirus family has not been reported. Prior studies with Kaposi's sarcoma-associated herpesvirus (KSHV) have indicated that the viral chromatin shares many biological properties exhibited by the host cell genome, essentially behaving as a mini human chromosome. Thus, we hypothesized that the KSHV genome may be organized in a similar manner. In this report, we describe the domain structure of the latent and lytic KSHV genome at 500 bp resolution and present a 3D genomic structural model for KSHV under each condition. These results add new insights into the complex regulation of the viral life cycle.
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16
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Combs LR, Spires LM, Alonso JD, Papp B, Toth Z. KSHV RTA Induces Degradation of the Host Transcription Repressor ID2 To Promote the Viral Lytic Cycle. J Virol 2022; 96:e0010122. [PMID: 35604218 PMCID: PMC9215225 DOI: 10.1128/jvi.00101-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/05/2022] [Indexed: 11/20/2022] Open
Abstract
The immediate early viral protein replication and transcription activator (RTA) of Kaposi's sarcoma-associated herpesvirus (KSHV) is essential for activating the lytic cycle of KSHV. RTA induces the KSHV lytic cycle by several mechanisms, acting as a viral transcription factor that directly induces viral and host genes and acting as a viral E3 ubiquitin ligase by degrading host proteins that block viral lytic replication. Recently, we have characterized the global gene expression changes in primary effusion lymphoma (PEL) upon lytic reactivation of KSHV, which also led to the identification of rapidly downregulated genes such as ID2, an inhibitor of basic helix-loop-helix transcription factors. Here, we demonstrate that ID2 overexpression in PEL ablates KSHV lytic reactivation, indicating that ID2 inhibits the KSHV lytic cycle. Furthermore, we show that while ID2 is highly expressed during latency, its protein level is rapidly reduced by 4 h postinduction during lytic reactivation. Our results indicate that RTA binds to ID2 and induces its degradation during the KSHV lytic cycle by N-terminal ubiquitination through the ubiquitin-proteasome pathway. Importantly, we found that not only KSHV RTA but also its Epstein-Barr virus (EBV) and murine gammaherpesvirus 68 (MHV68) homologs interact with ID2, and they can induce the degradation of all four members of the ID protein family, suggesting an evolutionarily conserved interplay between gammaherpesvirus RTAs and ID proteins. Taken together, we propose that ID2 acts as a repressor of the KSHV lytic cycle, which is counteracted by its RTA-mediated degradation. We also predict that ID proteins may act as restriction factors of the lytic phase of the other gammaherpesviruses as well. IMPORTANCE In addition to its transcription regulatory role, RTA is also known to have an E3 ubiquitin ligase activity, which RTA utilizes for inducing protein degradation. However, it is still largely unknown what host factors are downregulated during KSHV lytic reactivation by RTA-mediated protein degradation and what the biological significance of the degradation of these host factors is. In this study, we discovered that RTA employs N-terminal ubiquitination to induce degradation of ID2, a potent transcription repressor of host genes, via the ubiquitin-proteasome pathway to promote KSHV lytic reactivation in PEL cells. Furthermore, we found that not only KSHV RTA but also RTA of EBV and MHV68 gammaherpesviruses can induce the degradation of all four human ID proteins, indicating that the interplay between gammaherpesvirus RTAs and ID proteins is evolutionarily conserved.
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Affiliation(s)
- Lauren R. Combs
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Lauren McKenzie Spires
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Juan D. Alonso
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Bernadett Papp
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- University of Florida Genetics Institute, Gainesville, Florida, USA
- University of Florida Health Cancer Center, Gainesville, Florida, USA
- University of Florida Center for Orphaned Autoimmune Disorders, Gainesville, Florida, USA
- University of Florida Informatics Institute, Gainesville, Florida, USA
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- University of Florida Genetics Institute, Gainesville, Florida, USA
- University of Florida Health Cancer Center, Gainesville, Florida, USA
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17
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Kumar S, Ramamurthy C, Choudhary D, Sekar A, Patra A, Bhavesh NS, Vivekanandan P. Contrasting roles for G-quadruplexes in regulating human Bcl-2 and virus homologues KSHV KS-Bcl-2 and EBV BHRF1. Sci Rep 2022; 12:5019. [PMID: 35322051 PMCID: PMC8943185 DOI: 10.1038/s41598-022-08161-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 03/03/2022] [Indexed: 01/14/2023] Open
Abstract
Herpesviruses are known to acquire several genes from their hosts during evolution. We found that a significant proportion of virus homologues encoded by HSV-1, HSV-2, EBV and KSHV and their human counterparts contain G-quadruplex motifs in their promoters. We sought to understand the role of G-quadruplexes in the regulatory regions of viral Bcl-2 homologues encoded by KSHV (KS-Bcl-2) and EBV (BHRF1). We demonstrate that the KSHV KS-Bcl-2 and the EBV BHRF1 promoter G-quadruplex motifs (KSHV-GQ and EBV-GQ) form stable intramolecular G-quadruplexes. Ligand-mediated stabilization of KS-Bcl-2 and BHRF1 promoter G-quadruplexes significantly increased the promoter activity resulting in enhanced transcription of these viral Bcl-2 homologues. Mutations disrupting KSHV-GQ and EBV-GQ inhibit promoter activity and render the KS-Bcl-2 and the BHRF1 promoters non-responsive to G-quadruplex ligand. In contrast, promoter G-quadruplexes of human bcl-2 gene inhibit promoter activity. Further, KS-Bcl-2 and BHRF1 promoter G-quadruplexes augment RTA (a virus-encoded transcription factor)-mediated increase in viral bcl-2 promoter activity. In sum, this work highlights how human herpesviruses have evolved to exploit promoter G-quadruplexes to regulate virus homologues to counter their cellular counterparts.
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Affiliation(s)
- Shivani Kumar
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Chitteti Ramamurthy
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Divya Choudhary
- Department of Chemical Engineering, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Aashika Sekar
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Delhi, New Delhi, 110016, India
| | - Anupam Patra
- Transcription Regulation Group, International Centre for Genetic Engineering and Biotechnology, Delhi, New Delhi, 110067, India
| | - Neel Sarovar Bhavesh
- Transcription Regulation Group, International Centre for Genetic Engineering and Biotechnology, Delhi, New Delhi, 110067, India
| | - Perumal Vivekanandan
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, New Delhi, 110016, India.
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18
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Sandhu PK, Damania B. The regulation of KSHV lytic reactivation by viral and cellular factors. Curr Opin Virol 2022; 52:39-47. [PMID: 34872030 PMCID: PMC8844089 DOI: 10.1016/j.coviro.2021.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 11/03/2021] [Indexed: 02/03/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic herpesvirus that exhibits two distinct phases of infection in the host-latent and lytic. The quiescent latent phase is defined by limited expression of a subset of viral proteins and microRNAs, and an absence of virus production. KSHV periodically reactivates from latency to undergo active lytic replication, leading to production of new infectious virions. This switch from the latent to the lytic phase requires the viral protein regulator of transcription activator (RTA). RTA, along with other virally encoded proteins, is aided by host factors to facilitate this transition. Herein, we highlight the key host proteins that are involved in mediating RTA activation and KSHV lytic replication and discuss the cellular processes in which they function. We will also focus on the modulation of viral reactivation by the innate immune system, and how KSHV influences key immune signaling pathways to aid its own lifecycle.
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Affiliation(s)
- Praneet Kaur Sandhu
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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19
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Clinical Manifestations and Epigenetic Regulation of Oral Herpesvirus Infections. Viruses 2021; 13:v13040681. [PMID: 33920978 PMCID: PMC8071331 DOI: 10.3390/v13040681] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/13/2021] [Accepted: 04/13/2021] [Indexed: 12/20/2022] Open
Abstract
The oral cavity is often the first site where viruses interact with the human body. The oral epithelium is a major site of viral entry, replication and spread to other cell types, where chronic infection can be established. In addition, saliva has been shown as a primary route of person-to-person transmission for many viruses. From a clinical perspective, viral infection can lead to several oral manifestations, ranging from common intraoral lesions to tumors. Despite the clinical and biological relevance of initial oral infection, little is known about the mechanism of regulation of the viral life cycle in the oral cavity. Several viruses utilize host epigenetic machinery to promote their own life cycle. Importantly, viral hijacking of host chromatin-modifying enzymes can also lead to the dysregulation of host factors and in the case of oncogenic viruses may ultimately play a role in promoting tumorigenesis. Given the known roles of epigenetic regulation of viral infection, epigenetic-targeted antiviral therapy has been recently explored as a therapeutic option for chronic viral infection. In this review, we highlight three herpesviruses with known roles in oral infection, including herpes simplex virus type 1, Epstein–Barr virus and Kaposi’s sarcoma-associated herpesvirus. We focus on the respective oral clinical manifestations of these viruses and their epigenetic regulation, with a specific emphasis on the viral life cycle in the oral epithelium.
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Long W, Zhao G, Wu Y, Liu Y. Gallic acid inhibits Kaposi's Sarcoma-associated herpesvirus lytic reactivation by suppressing RTA transcriptional activities. Food Sci Nutr 2021; 9:847-854. [PMID: 33598168 PMCID: PMC7866607 DOI: 10.1002/fsn3.2048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/12/2020] [Accepted: 11/21/2020] [Indexed: 12/17/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV), an oncogenic virus, has two life cycle modes: the latent and lytic phases. KSHV lytic reactivation is known to be important both for viral propagation and for KSHV-induced tumorigenesis. The KSHV replication and transcription activator (RTA) protein is essential for lytic reactivation. Gallic acid (GA), one of the most abundant phenolic acids in the plant kingdom, has been shown potential chemotherapeutic efficacy against microbial and cancer. However, the effects of GA on KSHV replication and KSHV-induced tumorigenesis have not yet been reported. Here, we report that GA induces apoptotic cell death in BCBL-1 cells in a dose-dependent manner. GA inhibits KSHV reactivation and reduces the production of progeny virus from KSHV-harboring cells. GA inhibits RTA transcriptional activities by suppressing its binding to target gene promoters. These results suggest that GA may represent a novel strategy for the treatment of KSHV infection and KSHV-associated lymphomas.
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Affiliation(s)
- Wen‐Ying Long
- Central LaboratoryThe Fourth Affiliated HospitalZhejiang University School of MedicineN1 Shangcheng AvenueYiwu322000China
| | - Guo‐hua Zhao
- Department of NeurologyThe Fourth Affiliated HospitalZhejiang University School of MedicineN1 Shangcheng AvenueYiwu322000China
| | - Yao Wu
- Central LaboratoryThe Fourth Affiliated HospitalZhejiang University School of MedicineN1 Shangcheng AvenueYiwu322000China
| | - Ying Liu
- Central LaboratoryThe Fourth Affiliated HospitalZhejiang University School of MedicineN1 Shangcheng AvenueYiwu322000China
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21
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The interplay between EBV and KSHV viral products and NF-κB pathway in oncogenesis. Infect Agent Cancer 2020; 15:62. [PMID: 33072180 PMCID: PMC7559203 DOI: 10.1186/s13027-020-00317-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 07/29/2020] [Indexed: 02/08/2023] Open
Abstract
Among the DNA tumor viruses Epstein-Barr virus (EBV) and Kaposi sarcoma herpesvirus (KSHV), account for a considerable percentage of virus-associated cancers. Deregulation of transcription factors signaling pathways is one of the most significant oncogenic characteristics of EBV and KSHV. NF-κB is a transcription factor that play a remarkable role in oncogenesis because of its function as a master regulator of a spectrum of genes involved in physiological and pathophysiological process. Constitutive activation of NF-κB is a frequent and well-described event in many human malignancies. Compelling evidence represent EBV and KSHV are capable of targeting different components of NF-κB cascade. Here, we summarized recent findings to clarify the precise relationship between dysregulation of NF-κB and EBV and KSHV-related malignancies. This essay also emphasizes on contribution of various viral products in developing cancer through alteration of NF-κB signaling pathway.
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Park A, Oh S, Jung KL, Choi UY, Lee HR, Rosenfeld MG, Jung JU. Global epigenomic analysis of KSHV-infected primary effusion lymphoma identifies functional MYC superenhancers and enhancer RNAs. Proc Natl Acad Sci U S A 2020; 117:21618-21627. [PMID: 32817485 PMCID: PMC7474655 DOI: 10.1073/pnas.1922216117] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Enhancers play indispensable roles in cell proliferation and survival through spatiotemporally regulating gene transcription. Active enhancers and superenhancers often produce noncoding enhancer RNAs (eRNAs) that precisely control RNA polymerase II activity. Kaposi's sarcoma-associated herpesvirus (KSHV) is a human oncogenic gamma-2 herpesvirus that causes Kaposi's sarcoma and primary effusion lymphoma (PEL). It is well characterized that KSHV utilizes host epigenetic machineries to control the switch between two lifecycles, latency and lytic replication. However, how KSHV impacts host epigenome at different stages of viral lifecycle is not well understood. Using global run-on sequencing (GRO-seq) and chromatin-immunoprecipitation sequencing (ChIP-seq), we profiled the dynamics of host transcriptional regulatory elements during latency and lytic replication of KSHV-infected PEL cells. This revealed that a number of critical host genes for KSHV latency, including MYC proto-oncogene, were under the control of superenhancers whose activities were globally repressed upon viral reactivation. The eRNA-expressing MYC superenhancers were located downstream of the MYC gene in KSHV-infected PELs and played a key role in MYC expression. RNAi-mediated depletion or dCas9-KRAB CRISPR inhibition of eRNA expression significantly reduced MYC mRNA level in PELs, as did the treatment of an epigenomic drug that globally blocks superenhancer function. Finally, while cellular IRF4 acted upon eRNA expression and superenhancer function for MYC expression during latency, KSHV viral IRF4 repressed cellular IRF4 expression, decreasing MYC expression and thereby, facilitating lytic replication. These results indicate that KSHV acts as an epigenomic driver that modifies host epigenomic status upon reactivation by effectively regulating host enhancer function.
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Affiliation(s)
- Angela Park
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033
| | - Soohwan Oh
- Graduate Program of Biological Sciences, University of California San Diego, La Jolla, CA 92093
- HHMI, University of California San Diego, La Jolla, CA 92093
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Kyle L Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033
| | - Un Yung Choi
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033
| | - Hye-Ra Lee
- Department of Biotechnology and Bioinformatics, College of Science and Technology, Korea University, 30019 Sejong, South Korea
| | - Michael G Rosenfeld
- HHMI, University of California San Diego, La Jolla, CA 92093;
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA 92093
| | - Jae U Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033;
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Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication Is Independent of Anaphase-Promoting Complex Activity. J Virol 2020; 94:JVI.02079-19. [PMID: 32295923 PMCID: PMC7307157 DOI: 10.1128/jvi.02079-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/12/2020] [Indexed: 11/20/2022] Open
Abstract
The anaphase-promoting complex, or cyclosome (APC/C), is a large E3 ubiquitin ligase composed of 14 subunits. The activity of APC/C oscillates during the cell cycle to ensure a timely transition through each phase by promoting the degradation of important cell cycle regulators. Of the human herpesviruses, cytomegalovirus (HCMV) and Epstein-Barr virus (EBV) both impair the activity of APC/C during their lytic replication cycle through virus-encoded protein kinases. Here, we addressed whether the oncogenic Kaposi's sarcoma-associated herpesvirus (KSHV) deregulates the activity of APC/C during the lytic replication cycle. To this end, we used the well-characterized iSLK.219 cell model of KSHV infection and established a new infection model of primary lymphatic endothelial cells (LECs) infected with a lytically replicating KSHV BAC16 mutant. In contrast to those of EBV and HCMV, the KSHV lytic cycle occurs while the APC/C is active. Moreover, interfering with the activity of APC/C did not lead to major changes in the production of infectious virus. We further investigated whether rereplication stress induced by the unscheduled activation of the APC/C-CDH1 complex affects the number and integrity of KSHV viral episomes. Deep sequencing of the viral episomes and host chromosomes in iSLK.219 cells revealed that, while distinct regions in the cellular chromosomes were severely affected by rereplication stress, the integrity of the viral episomes remained unaltered.IMPORTANCE DNA viruses have evolved complex strategies to gain control over the cell cycle. Several of them target APC/C, a key cellular machinery that controls the timely progression of the cell cycle, by either blocking or enhancing its activity. Here, we investigated the activity of APC/C during the lytic replication cycle of KSHV and found that, in contrast to that of KSHV's close relatives EBV and HCMV, KSHV lytic replication occurs while the APC/C is active. Perturbing APC/C activity by depleting a core protein or the adaptor proteins of the catalytic domain, and hence interfering with normal cell-cycle progression, did not affect virus replication. This suggests that KSHV has evolved to replicate independently of the activity of APC/C and in various cell cycle conditions.
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Sun C, Guo Y, Zhou W, Xia C, Xing X, Chen J, Li X, Zhu H, Lu J. p300 promotes cell proliferation through suppressing Kaposi's sarcoma-associated herpesvirus (KSHV) reactivation in the infected B-lymphoma cells. Virus Res 2020; 286:198066. [PMID: 32553609 DOI: 10.1016/j.virusres.2020.198066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/10/2020] [Accepted: 06/12/2020] [Indexed: 01/14/2023]
Abstract
Primary Effusion Lymphoma (PEL) is a B-cell lymphoma associated with Kaposi's sarcoma herpesvirus (KSHV) infection. However, the mechanism of oncogenesis of PEL is still unclear. Studies have shown that the cellular transcriptional coactivator p300 regulates the interaction between host and virus, which plays a vital role in viral replication. In this study, we investigated the role of p300 in BCBL1 cells during the KSHV life cycle. We found that p300 knockout resulted in an overall increase for the early lytic genes and changed the expression of genes associated with tumor development, proliferation, and the immune response in the KSHV infected B cells. However, knockout of p300 significantly inhibited the expression of the immediate-early gene RTA and the late lytic gene K8 after KSHV lytic activation. Additionally, the intracellular KSHV genome copy number and the virion production were reduced. These results demonstrated that p300 plays a crucial role in suppressing KSHV viral replication in BCBL1. Furthermore, we observed that the growth of BCBL1 was inhibited by knockout of p300, which confirmed our findings that p300 promotes cell proliferation. This study further provided evidence that p300 plays an important role in the pathogenesis of BCBL1, which might lead to the oncogenesis of PEL caused by KSHV infection.
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Affiliation(s)
- Chuankai Sun
- Department of Biotechnology, College of Life Science and Technology, Jinan University Guangzhou, 510632, China
| | - Yizhen Guo
- Department of Biotechnology, College of Life Science and Technology, Jinan University Guangzhou, 510632, China
| | - Wei Zhou
- The Biomedical Translational Research Institute, Jinan University Guangzhou, 510632, China
| | - Chuan Xia
- Department of Biotechnology, College of Life Science and Technology, Jinan University Guangzhou, 510632, China
| | - Xiwen Xing
- Department of Biotechnology, College of Life Science and Technology, Jinan University Guangzhou, 510632, China
| | - Jun Chen
- Department of Biotechnology, College of Life Science and Technology, Jinan University Guangzhou, 510632, China
| | - Xin Li
- Department of Biotechnology, College of Life Science and Technology, Jinan University Guangzhou, 510632, China
| | - Hua Zhu
- Department of Biotechnology, College of Life Science and Technology, Jinan University Guangzhou, 510632, China
| | - Jie Lu
- Department of Biotechnology, College of Life Science and Technology, Jinan University Guangzhou, 510632, China.
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25
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Fröhlich J, Grundhoff A. Epigenetic control in Kaposi sarcoma-associated herpesvirus infection and associated disease. Semin Immunopathol 2020; 42:143-157. [PMID: 32219477 PMCID: PMC7174275 DOI: 10.1007/s00281-020-00787-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 01/20/2020] [Indexed: 12/15/2022]
Abstract
Kaposi sarcoma-associated herpesvirus (KSHV) is the etiologic agent of several malignancies of endothelial and B-cell origin. The fact that latently infected tumor cells in these malignancies do not express classical viral oncogenes suggests that pathogenesis of KSHV-associated disease results from multistep processes that, in addition to constitutive viral gene expression, may require accumulation of cellular alterations. Heritable changes of the epigenome have emerged as an important co-factor that contributes to the pathogenesis of many non-viral cancers. Since KSHV encodes a number of factors that directly or indirectly manipulate host cell chromatin, it is an intriguing possibility that epigenetic reprogramming also contributes to the pathogenesis of KSHV-associated tumors. The fact that heritable histone modifications have also been shown to regulate viral gene expression programs in KSHV-infected tumor cells underlines the importance of epigenetic control during latency and tumorigenesis. We here review what is presently known about the role of epigenetic regulation of viral and host chromatin in KSHV infection and discuss how viral manipulation of these processes may contribute to the development of KSHV-associated disease.
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Affiliation(s)
- Jacqueline Fröhlich
- Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Adam Grundhoff
- Heinrich-Pette-Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany.
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Epigenetic factor siRNA screen during primary KSHV infection identifies novel host restriction factors for the lytic cycle of KSHV. PLoS Pathog 2020; 16:e1008268. [PMID: 31923286 PMCID: PMC6977772 DOI: 10.1371/journal.ppat.1008268] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 01/23/2020] [Accepted: 12/09/2019] [Indexed: 12/12/2022] Open
Abstract
Establishment of viral latency is not only essential for lifelong Kaposi’s sarcoma-associated herpesvirus (KSHV) infection, but it is also a prerequisite of viral tumorigenesis. The latent viral DNA has a complex chromatin structure, which is established in a stepwise manner regulated by host epigenetic factors during de novo infection. However, despite the importance of viral latency in KSHV pathogenesis, we still have limited information about the repertoire of epigenetic factors that are critical for the establishment and maintenance of KSHV latency. Therefore, the goal of this study was to identify host epigenetic factors that suppress lytic KSHV genes during primary viral infection, which would indicate their role in latency establishment. We performed an siRNA screen targeting 392 host epigenetic factors during primary infection and analyzed which ones affect the expression of the viral replication and transcription activator (RTA) and/or the latency-associated nuclear antigen (LANA), which are viral genes essential for lytic replication and latency, respectively. As a result, we identified the Nucleosome Remodeling and Deacetylase (NuRD) complex, Tip60 and Tip60-associated co-repressors, and the histone demethylase KDM2B as repressors of KSHV lytic genes during both de novo infection and the maintenance of viral latency. Furthermore, we showed that KDM2B rapidly binds to the incoming viral DNA as early as 8 hpi, and can limit the enrichment of activating histone marks on the RTA promoter favoring the downregulation of RTA expression even prior to the polycomb proteins-regulated heterochromatin establishment on the viral genome. Strikingly, KDM2B can also suppress viral gene expression and replication during lytic infection of primary gingival epithelial cells, revealing that KDM2B can act as a host restriction factor of the lytic cycle of KSHV during both latent and lytic infections in multiple different cell types. Latent viral infection of cancer cells in KSHV-associated tumors is critical for the growth and survival of the cancer. Thus, revealing how lytic viral genes get suppressed through epigenetic regulation following de novo KSHV infection, resulting in the establishment of latency, is central to understanding the pathogenesis of KSHV infection. Importantly, the epigenetic factors that we identified as suppressors of KSHV lytic genes are not only crucial for the establishment and maintenance of KSHV latency in different cell types, but also several of them can block lytic KSHV infection in oral epithelial cells. Since herpesviruses often rely on similar sets of host epigenetic factors, the characterization of these newly identified epigenetic factors in KSHV infection may help to better understand fundamental epigenetic mechanisms that may also be utilized by other herpesviruses to establish latency following primary infection.
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27
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Golas G, Alonso JD, Toth Z. Characterization of de novo lytic infection of dermal lymphatic microvascular endothelial cells by Kaposi's sarcoma-associated herpesvirus. Virology 2019; 536:27-31. [PMID: 31394409 DOI: 10.1016/j.virol.2019.07.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 07/21/2019] [Accepted: 07/29/2019] [Indexed: 12/12/2022]
Abstract
The biology of primary lytic Kaposi's sarcoma-associated herpesvirus (KSHV) infection is still not well understood, which is largely attributed to the lack of cell lines permissive to robust lytic KSHV infection in vitro. Our study demonstrates that primary human dermal lymphatic microvascular endothelial cells (HDLMEC) support lytic KSHV replication following de novo infection, resulting in robust KSHV production, indicating that HDLMECs are suitable for studying the regulation of primary lytic KSHV infection. Importantly, by utilizing lytically infected HDLMECs, we show for the first time that the KSHV latent genes LANA and viral cyclin are required for lytic replication during de novo lytic infection, a function of these latent genes that has not yet been recognized. Since Kaposi's sarcoma is considered to be originated from infected lymphatic endothelial cells, HDLMECs represent a valuable in vitro cell culture model for investigating lytic KSHV infection, which has been understudied in KSHV pathogenesis.
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Affiliation(s)
- Gavin Golas
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL, 32610, USA
| | - Juan D Alonso
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL, 32610, USA
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, 1395 Center Drive, Gainesville, FL, 32610, USA; UF Genetics Institute, Gainesville, FL, 32610, USA; UF Health Cancer Center, Gainesville, FL, 32610, USA.
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28
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Gonzalez-Lopez O, DeCotiis J, Goyeneche C, Mello H, Vicente-Ortiz BA, Shin HJ, Driscoll KE, Du P, Palmeri D, Lukac DM. A herpesvirus transactivator and cellular POU proteins extensively regulate DNA binding of the host Notch signaling protein RBP-Jκ to the virus genome. J Biol Chem 2019; 294:13073-13092. [PMID: 31308175 DOI: 10.1074/jbc.ra118.007331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 07/10/2019] [Indexed: 12/11/2022] Open
Abstract
Reactivation of Kaposi's sarcoma-associated herpesvirus (KSHV) from latency requires the viral transactivator Rta to contact the host protein Jκ recombination signal-binding protein (RBP-Jκ or CSL). RBP-Jκ normally binds DNA sequence-specifically to determine the transcriptional targets of the Notch-signaling pathway, yet Notch alone cannot reactivate KSHV. We previously showed that Rta stimulates RBP-Jκ DNA binding to the viral genome. On a model viral promoter, this function requires Rta to bind to multiple copies of an Rta DNA motif (called "CANT" or Rta-c) proximal to an RBP-Jκ motif. Here, high-resolution ChIP/deep sequencing from infected primary effusion lymphoma cells revealed that RBP-Jκ binds nearly exclusively to different sets of viral genome sites during latency and reactivation. RBP-Jκ bound DNA frequently, but not exclusively, proximal to Rta bound to single, but not multiple, Rta-c motifs. To discover additional regulators of RBP-Jκ DNA binding, we used bioinformatics to identify cellular DNA-binding protein motifs adjacent to either latent or reactivation-specific RBP-Jκ-binding sites. Many of these cellular factors, including POU class homeobox (POU) proteins, have known Notch or herpesvirus phenotypes. Among a set of Rta- and RBP-Jκ-bound promoters, Rta transactivated only those that also contained POU motifs in conserved positions. On some promoters, POU factors appeared to inhibit RBP-Jκ DNA binding unless Rta bound to a proximal Rta-c motif. Moreover, POU2F1/Oct-1 expression was induced during KSHV reactivation, and POU2F1 knockdown diminished infectious virus production. Our results suggest that Rta and POU proteins broadly regulate DNA binding of RBP-Jκ during KSHV reactivation.
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Affiliation(s)
- Olga Gonzalez-Lopez
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103; Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103
| | - Jennifer DeCotiis
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103; Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103
| | - Corey Goyeneche
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103; Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103
| | - Helena Mello
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103; Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103
| | - Bryan Alexis Vicente-Ortiz
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103
| | - Hye Jin Shin
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103; Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103
| | - Kyla E Driscoll
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103
| | - Peicheng Du
- High Performance and Research Computing, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103
| | - Diana Palmeri
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103
| | - David M Lukac
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103; Graduate School of Biomedical Sciences, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Rutgers University, Newark, New Jersey 07103.
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