1
|
Ye X, Guerin LN, Chen Z, Rajendren S, Dunker W, Zhao Y, Zhang R, Hodges E, Karijolich J. Enhancer-promoter activation by the Kaposi sarcoma-associated herpesvirus episome maintenance protein LANA. Cell Rep 2024; 43:113888. [PMID: 38416644 PMCID: PMC11005752 DOI: 10.1016/j.celrep.2024.113888] [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: 05/02/2023] [Revised: 12/29/2023] [Accepted: 02/14/2024] [Indexed: 03/01/2024] Open
Abstract
Higher-order genome structure influences the transcriptional regulation of cellular genes through the juxtaposition of regulatory elements, such as enhancers, close to promoters of target genes. While enhancer activation has emerged as an important facet of Kaposi sarcoma-associated herpesvirus (KSHV) biology, the mechanisms controlling enhancer-target gene expression remain obscure. Here, we discover that the KSHV genome tethering protein latency-associated nuclear antigen (LANA) potentiates enhancer-target gene expression in primary effusion lymphoma (PEL), a highly aggressive B cell lymphoma causally associated with KSHV. Genome-wide analyses demonstrate increased levels of enhancer RNA transcription as well as activating chromatin marks at LANA-bound enhancers. 3D genome conformation analyses identified genes critical for latency and tumorigenesis as targets of LANA-occupied enhancers, and LANA depletion results in their downregulation. These findings reveal a mechanism in enhancer-gene coordination and describe a role through which the main KSHV tethering protein regulates essential gene expression in PEL.
Collapse
Affiliation(s)
- Xiang Ye
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Lindsey N Guerin
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Ziche Chen
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Suba Rajendren
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - William Dunker
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yang Zhao
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Ruilin Zhang
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Emily Hodges
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt-Ingram Cancer Center, Nashville, TN 37232, USA; Vanderbilt Genetics Institute, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - John Karijolich
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Vanderbilt-Ingram Cancer Center, Nashville, TN 37232, USA; Vanderbilt Institute for Infection, Immunology, and Inflammation, Nashville, TN 37232, USA; Vanderbilt Center for Immunobiology, Nashville, TN 37232, USA.
| |
Collapse
|
2
|
Kim ET, Kim KD. Topological implications of DNA tumor viral episomes. BMB Rep 2022; 55:587-594. [PMID: 36379513 PMCID: PMC9813422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Indexed: 12/29/2022] Open
Abstract
A persistent DNA tumor virus infection transforms normal cells into cancer cells by either integrating its genome into host chromosomes or retaining it as an extrachromosomal entity called episome. Viruses have evolved mechanisms for attaching episomes to infected host cell chromatin to efficiently segregate the viral genome during mitosis. It has been reported that viral episome can affect the gene expression of the host chromosomes through interactions between viral episomes and epigenetic regulatory host factors. This mini review summarizes our current knowledge of the tethering sites of viral episomes, such as EBV, KSHV, and HBV, on host chromosomes analyzed by three-dimensional genomic tools. [BMB Reports 2022; 55(12): 587-594].
Collapse
Affiliation(s)
- Eui Tae Kim
- Department of Microbiology and Immunology, Jeju National University College of Medicine, Jeju 63241, Korea,Department of Biomedicine & Drug Development, Jeju National University, Jeju 63241, Korea
| | - Kyoung-Dong Kim
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Korea,Corresponding author. Tel: +82-31-670-3359; Fax: +82-31-675-3108; E-mail:
| |
Collapse
|
3
|
Targeting the Nucleosome Acidic Patch by Viral Proteins: Two Birds with One Stone? mBio 2022; 13:e0173321. [PMID: 35343785 PMCID: PMC9040877 DOI: 10.1128/mbio.01733-21] [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] [Indexed: 11/20/2022] Open
Abstract
The past decade illuminated the H2A-H2B acidic patch as a cornerstone for both nucleosome recognition and chromatin structure regulation. Higher-order folding of chromatin arrays is mediated by interactions of histone H4 tail with an adjacent nucleosome acidic patch. Dynamic chromatin folding ensures a proper regulation of nuclear functions fundamental to cellular homeostasis. Many cellular factors have been shown to act on chromatin by tethering nucleosomes via an arginine anchor binding to the acidic patch. This tethering mechanism has also been described for several viral proteins. In this minireview, we will discuss the structural basis for acidic patch engagement by viral proteins and the implications during respective viral infections. We will also discuss a model in which acidic patch occupancy by these non-self viral proteins alters the local chromatin state by preventing H4 tail-mediated higher-order chromatin folding.
Collapse
|
4
|
Tan M, Li S, Juillard F, Chitas R, Custódio TF, Xue H, Szymula A, Sun Q, Liu B, Álvarez ÁL, Chen S, Huang J, Simas JP, McVey CE, Kaye KM. MLL1 is regulated by KSHV LANA and is important for virus latency. Nucleic Acids Res 2021; 49:12895-12911. [PMID: 34850113 PMCID: PMC8682764 DOI: 10.1093/nar/gkab1094] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 09/29/2021] [Accepted: 10/20/2021] [Indexed: 01/19/2023] Open
Abstract
Mixed lineage leukemia 1 (MLL1) is a histone methyltransferase. Kaposi's sarcoma-associated herpesvirus (KSHV) is a leading cause of malignancy in AIDS. KSHV latently infects tumor cells and its genome is decorated with epigenetic marks. Here, we show that KSHV latency-associated nuclear antigen (LANA) recruits MLL1 to viral DNA where it establishes H3K4me3 modifications at the extensive KSHV terminal repeat elements during primary infection. LANA interacts with MLL1 complex members, including WDR5, integrates into the MLL1 complex, and regulates MLL1 activity. We describe the 1.5-Å crystal structure of N-terminal LANA peptide complexed with MLL1 complex member WDR5, which reveals a potential regulatory mechanism. Disruption of MLL1 expression rendered KSHV latency establishment highly deficient. This deficiency was rescued by MLL1 but not by catalytically inactive MLL1. Therefore, MLL1 is LANA regulable and exerts a central role in virus infection. These results suggest broad potential for MLL1 regulation, including by non-host factors.
Collapse
Affiliation(s)
- Min Tan
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Shijun Li
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Franceline Juillard
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Rute Chitas
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras 2780-157, Portugal
| | - Tânia F Custódio
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras 2780-157, Portugal
| | - Han Xue
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 200031 Shanghai, China
| | - Agnieszka Szymula
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Qiming Sun
- Departments of Biochemistry and Cardiology, Second Affiliated Hospital Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Bing Liu
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Ángel L Álvarez
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - She Chen
- Proteomics Center, National Institute of Biological Sciences, Beijing 102206, China
| | - Jing Huang
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine 200125 Shanghai, China
| | - J Pedro Simas
- Instituto de Medicina Molecular, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal.,Católica Biomedical Research, Católica Medical School, Universidade Católica Portuguesa, Palma de Cima, 1649-023 Lisboa, Portugal
| | - Colin E McVey
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras 2780-157, Portugal
| | - Kenneth M Kaye
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| |
Collapse
|
5
|
Naimo E, Zischke J, Schulz TF. Recent Advances in Developing Treatments of Kaposi's Sarcoma Herpesvirus-Related Diseases. Viruses 2021; 13:1797. [PMID: 34578378 PMCID: PMC8473310 DOI: 10.3390/v13091797] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 12/27/2022] Open
Abstract
Kaposi-sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8) is the causative agent of several malignancies, including Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). Active KSHV replication has also been associated with a pathological condition called KSHV inflammatory cytokine syndrome (KICS), and KSHV may play a role in rare cases of post-transplant polyclonal lymphoproliferative disorders. Several commonly used herpesviral DNA polymerase inhibitors are active against KSHV in tissue culture. Unfortunately, they are not always efficacious against KSHV-induced diseases. To improve the outcome for the patients, new therapeutics need to be developed, including treatment strategies that target either viral proteins or cellular pathways involved in tumor growth and/or supporting the viral life cycle. In this review, we summarize the most commonly established treatments against KSHV-related diseases and review recent developments and promising new compounds that are currently under investigation or on the way to clinical use.
Collapse
Affiliation(s)
- Eleonora Naimo
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (E.N.); (J.Z.)
- German Centre for Infection Research, Hannover-Braunschweig Site, 38023 Braunschweig, Germany
| | - Jasmin Zischke
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (E.N.); (J.Z.)
- German Centre for Infection Research, Hannover-Braunschweig Site, 38023 Braunschweig, Germany
| | - Thomas F. Schulz
- Institute of Virology, Hannover Medical School, 30625 Hannover, Germany; (E.N.); (J.Z.)
- German Centre for Infection Research, Hannover-Braunschweig Site, 38023 Braunschweig, Germany
- Cluster of Excellence 2155 RESIST, Institute of Virology, Hannover Medical School, 30625 Hannover, Germany
| |
Collapse
|
6
|
Viruses and Skin Cancer. Int J Mol Sci 2021; 22:ijms22105399. [PMID: 34065594 PMCID: PMC8161099 DOI: 10.3390/ijms22105399] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/11/2022] Open
Abstract
Advances in virology and skin cancer over recent decades have produced achievements that have been recognized not only in the field of dermatology, but also in other areas of medicine. They have modified the therapeutic and preventive solutions that can be offered to some patients and represent a significant step forward in our knowledge of the biology of skin cancer. In this paper, we review the viral agents responsible for different types of skin cancer, especially for solid skin tumors. We focus on human papillomavirus and squamous cell cancers, Merkel cell polyomavirus and Merkel cell carcinoma, and human herpesvirus 8 and Kaposi’s sarcoma.
Collapse
|
7
|
Kim YJ, Kim Y, Kumar A, Kim CW, Toth Z, Cho NH, Lee HR. Kaposi's sarcoma-associated herpesvirus latency-associated nuclear antigen dysregulates expression of MCL-1 by targeting FBW7. PLoS Pathog 2021; 17:e1009179. [PMID: 33471866 PMCID: PMC7816990 DOI: 10.1371/journal.ppat.1009179] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 11/22/2020] [Indexed: 12/11/2022] Open
Abstract
Primary effusion lymphoma (PEL) is an aggressive B cell lymphoma that is etiologically linked to Kaposi’s sarcoma-associated herpesvirus (KSHV). Despite standard multi-chemotherapy treatment, PEL continues to cause high mortality. Thus, new strategies to control PEL are needed urgently. Here, we show that a phosphodegron motif within the KSHV protein, latency-associated nuclear antigen (LANA), specifically interacts with E3 ubiquitin ligase FBW7, thereby competitively inhibiting the binding of the anti-apoptotic protein MCL-1 to FBW7. Consequently, LANA-FBW7 interaction enhances the stability of MCL-1 by preventing its proteasome-mediated degradation, which inhibits caspase-3-mediated apoptosis in PEL cells. Importantly, MCL-1 inhibitors markedly suppress colony formation on soft agar and tumor growth of KSHV+PEL/BCBL-1 in a xenograft mouse model. These results strongly support the conclusion that high levels of MCL-1 expression enable the oncogenesis of PEL cells and thus, MCL-1 could be a potential drug target for KSHV-associated PEL. This work also unravels a mechanism by which an oncogenic virus perturbs a key component of the ubiquitination pathway to induce tumorigenesis. Primary effusion lymphoma (PEL), a highly aggressive B cell lymphoma, is associated with Kaposi’s sarcoma-associated herpesvirus (KSHV). However, the underlying mechanisms that govern the aggressiveness of KSHV-associated PEL are poorly understood. Here, we demonstrate that KSHV LANA interacts with cellular ubiquitin E3 ligase FBW7, sequestering MCL-1 from FBW7, which reduces MCL-1 ubiquitination. As such, LANA potently stabilizes and increases MCL-1 protein, leading to inhibition of caspase-3-mediated apoptosis in PEL cells. Furthermore, MCL-1 inhibitors efficiently blocked PEL progression in mouse xenograft model. These results suggest that LANA acts as a proto-oncogene via deregulating tumor suppressor FBW7, which upregulates anti-apoptotic MCL-1 expression. This study suggests drugs that target MCL-1 may serve as an effective therapy against KSHV+ PEL.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Viral/genetics
- Antigens, Viral/metabolism
- Apoptosis
- Cell Proliferation
- F-Box-WD Repeat-Containing Protein 7/genetics
- F-Box-WD Repeat-Containing Protein 7/metabolism
- Female
- Herpesvirus 8, Human/physiology
- Humans
- Lymphoma, Primary Effusion/genetics
- Lymphoma, Primary Effusion/metabolism
- Lymphoma, Primary Effusion/pathology
- Lymphoma, Primary Effusion/virology
- Mice
- Mice, Inbred NOD
- Mice, SCID
- Myeloid Cell Leukemia Sequence 1 Protein/genetics
- Myeloid Cell Leukemia Sequence 1 Protein/metabolism
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Phosphorylation
- Sarcoma, Kaposi/genetics
- Sarcoma, Kaposi/metabolism
- Sarcoma, Kaposi/pathology
- Sarcoma, Kaposi/virology
- Tumor Cells, Cultured
- Ubiquitination
- Xenograft Model Antitumor Assays
Collapse
Affiliation(s)
- Yeong Jun Kim
- Department of Biotechnology and Bioinformatics, College of Science and Technology, Korea University, Sejong, South Korea
| | - Yuri Kim
- Department of Microbiology and Immunology, Seoul National University college of Medicine, Seoul, South Korea
| | - Abhishek Kumar
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, United States of America
| | - Chan Woo Kim
- Department of Biotechnology and Bioinformatics, College of Science and Technology, Korea University, Sejong, South Korea
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, United States of America
| | - Nam Hyuk Cho
- Department of Microbiology and Immunology, Seoul National University college of Medicine, Seoul, South Korea
- Department of Biomedical Sciences, Seoul National University college of Medicine, Seoul, South Korea
| | - Hye-Ra Lee
- Department of Biotechnology and Bioinformatics, College of Science and Technology, Korea University, Sejong, South Korea
- Department of Lab Medicine, College of Medicine, Korea University, Seoul, South Korea
- * E-mail:
| |
Collapse
|
8
|
Lotke R, Schneeweiß U, Pietrek M, Günther T, Grundhoff A, Weidner-Glunde M, Schulz TF. Brd/BET Proteins Influence the Genome-Wide Localization of the Kaposi's Sarcoma-Associated Herpesvirus and Murine Gammaherpesvirus Major Latency Proteins. Front Microbiol 2020; 11:591778. [PMID: 33193257 PMCID: PMC7642799 DOI: 10.3389/fmicb.2020.591778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 09/28/2020] [Indexed: 01/22/2023] Open
Abstract
The rhadinoviruses Kaposi’s Sarcoma-associated herpesvirus (KSHV) and murine gammaherpesvirus (MHV-68) persist in infected hosts in a latent state that is characterized by the absence of virus production and by restricted viral gene expression. Their major latency protein, the latency-associated nuclear antigen (kLANA for KSHV and mLANA for MHV-68), is essential for viral genome maintenance and replication and involved in transcriptional regulation. Both kLANA and mLANA interact with cellular chromatin-associated proteins, among them the Bromodomain and Extra Terminal domain (Brd/BET) proteins, which recruit cellular and viral proteins to acetylated histones through their bromodomains and modulate cellular gene expression. Brd/BET proteins also play a role in the tethering, replication, segregation or integration of a diverse group of viral DNA genomes. In this study we explored if Brd/BET proteins influence the localization of the LANAs to preferential regions in the host chromatin and thereby contribute to kLANA- or mLANA-mediated transcriptional regulation. Using ChIP-Seq, we revealed a genome-wide co-enrichment of kLANA with Brd2/4 near cellular and viral transcriptional start sites (TSS). Treatment with I-BET151, an inhibitor of Brd/BET, displaced kLANA and Brd2/4 from TSS in the viral and host chromatin, but did not affect the direct binding of kLANA to kLANA-binding sites (LBS) in the KSHV latent origin of replication. Similarly, mLANA, but not a mLANA mutant deficient for binding to Brd2/4, also associated with cellular TSS. We compared the transcriptome of KSHV-infected with uninfected and kLANA-expressing human B cell lines, as well as a murine B cell line expressing mLANA or a Brd2/4-binding deficient mLANA mutant. We found that only a minority of cellular genes, whose TSS are occupied by kLANA or mLANA, is transcriptionally regulated by these latency proteins. Our findings extend previous reports on a preferential deposition of kLANA on cellular TSS and show that this characteristic chromatin association pattern is at least partially determined by the interaction of these viral latency proteins with members of the Brd/BET family of chromatin modulators.
Collapse
Affiliation(s)
- Rishikesh Lotke
- Institut für Virologie, Medizinische Hochschule Hannover, Hanover, Germany.,German Center for Infection Research, Hannover-Braunschweig and Hamburg Sites, Hanover, Germany
| | - Ulrike Schneeweiß
- Institut für Virologie, Medizinische Hochschule Hannover, Hanover, Germany
| | - Marcel Pietrek
- Institut für Virologie, Medizinische Hochschule Hannover, Hanover, Germany
| | - Thomas Günther
- Heinrich-Pette-Institut, Leibniz-Institut für Experimentelle Virologie, Hamburg, Germany
| | - Adam Grundhoff
- German Center for Infection Research, Hannover-Braunschweig and Hamburg Sites, Hanover, Germany.,Heinrich-Pette-Institut, Leibniz-Institut für Experimentelle Virologie, Hamburg, Germany
| | - Magdalena Weidner-Glunde
- Institut für Virologie, Medizinische Hochschule Hannover, Hanover, Germany.,German Center for Infection Research, Hannover-Braunschweig and Hamburg Sites, Hanover, Germany
| | - Thomas F Schulz
- Institut für Virologie, Medizinische Hochschule Hannover, Hanover, Germany.,German Center for Infection Research, Hannover-Braunschweig and Hamburg Sites, Hanover, Germany
| |
Collapse
|
9
|
KSHV LANA acetylation-selective acidic domain reader sequence mediates virus persistence. Proc Natl Acad Sci U S A 2020; 117:22443-22451. [PMID: 32820070 PMCID: PMC7486799 DOI: 10.1073/pnas.2004809117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Viruses modulate biochemical cellular pathways to permit infection. A recently described mechanism mediates selective protein interactions between acidic domain readers and unacetylated, lysine-rich regions, opposite of bromodomain function. Kaposi´s sarcoma (KS)-associated herpesvirus (KSHV) is tightly linked with KS, primary effusion lymphoma, and multicentric Castleman's disease. KSHV latently infects cells, and its genome persists as a multicopy, extrachromosomal episome. During latency, KSHV expresses a small subset of genes, including the latency-associated nuclear antigen (LANA), which mediates viral episome persistence. Here we show that LANA contains two tandem, partially overlapping, acidic domain sequences homologous to the SET oncoprotein acidic domain reader. This domain selectively interacts with unacetylated p53, as evidenced by reduced LANA interaction after overexpression of CBP, which acetylates p53, or with an acetylation mimicking carboxyl-terminal domain p53 mutant. Conversely, the interaction of LANA with an acetylation-deficient p53 mutant is enhanced. Significantly, KSHV LANA mutants lacking the acidic domain reader sequence are deficient for establishment of latency and persistent infection. This deficiency was confirmed under physiological conditions, on infection of mice with a murine gammaherpesvirus 68 chimera expressing LANA, where the virus was highly deficient in establishing latent infection in germinal center B cells. Therefore, LANA's acidic domain reader is critical for viral latency. These results implicate an acetylation-dependent mechanism mediating KSHV persistence and expand the role of acidic domain readers.
Collapse
|
10
|
De Leo A, Calderon A, Lieberman PM. Control of Viral Latency by Episome Maintenance Proteins. Trends Microbiol 2019; 28:150-162. [PMID: 31624007 DOI: 10.1016/j.tim.2019.09.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/30/2019] [Accepted: 09/05/2019] [Indexed: 12/12/2022]
Abstract
The human DNA tumor viruses Epstein-Barr virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV), and human papillomavirus (HPV) share the common property of persisting as multicopy episomes in the nuclei of rapidly dividing host cells. These episomes form the molecular basis for viral latency and are etiologically linked to virus-associated cancers. Episome maintenance requires epigenetic programming to ensure the proper control of viral gene expression, DNA replication, and genome copy number. For these viruses, episome maintenance requires a dedicated virus-encoded episome maintenance protein (EMP), namely LANA (KSHV), EBNA1 (EBV), and E2 (HPV). Here, we review common features of these viral EMPs and discuss recent advances in understanding how they contribute to the epigenetic control of viral episome maintenance during latency.
Collapse
|
11
|
Abstract
Persistent viral infections require a host cell reservoir that maintains functional copies of the viral genome. To this end, several DNA viruses maintain their genomes as extrachromosomal DNA minichromosomes in actively dividing cells. These viruses typically encode a viral protein that binds specifically to viral DNA genomes and tethers them to host mitotic chromosomes, thus enabling the viral genomes to hitchhike or piggyback into daughter cells. Viruses that use this tethering mechanism include papillomaviruses and the gammaherpesviruses Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus. This review describes the advantages and consequences of persistent extrachromosomal viral genome replication.
Collapse
Affiliation(s)
- Tami L Coursey
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Alison A McBride
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA;
| |
Collapse
|
12
|
Minichromosome Maintenance Proteins Cooperate with LANA during the G 1/S Phase of the Cell Cycle To Support Viral DNA Replication. J Virol 2019; 93:JVI.02256-18. [PMID: 30651368 DOI: 10.1128/jvi.02256-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 01/13/2019] [Indexed: 12/11/2022] Open
Abstract
Latency-associated nuclear antigen (LANA) is essential for maintaining the viral genome by regulating replication and segregation of the viral episomes. The virus maintains 50 to 100 episomal copies during latency and replicates in synchrony with the cellular DNA of the infected cells. Since virus lacks its own replication machinery, it utilizes the cellular proteins for replication and maintenance, and LANA has been shown to make many of these proteins available for replication by directly recruiting them to the viral origin of replication within the terminal repeat (TR) region. Our studies identified members of the minichromosome maintenance (MCM) complex as potential LANA-interacting proteins. Here, we show that LANA specifically interacts with the components of the MCM complex, primarily during the G1/S phase of the cell cycle. MCM3 and -4 of the MCM complex specifically bound to the amino-terminal domain, while MCM6 bound to both the amino- and carboxyl-terminal domains of LANA. The MCM binding region in the N-terminal domain mapped to the chromatin binding domain (CBD). LANA with point mutations in the carboxyl-terminal domain identified an MCM6 binding domain, and overexpression of that domain (amino acids [aa] 1100 to 1150) abolished TR replication. Introduction of a peptide encompassing the LANA aa 1104 to 1123 reduced MCM6 association with LANA and TR replication. Moreover, a recombinant Kaposi's sarcoma-associated herpesvirus (KSHV) expressing LANA with a deletion of aa 1100 to 1150 (BAC16Δ1100-1150, where BAC is bacmid) showed reduced replication and persistence of viral genome copies compared to levels with the wild-type BAC16. Additionally, the role of MCMs in viral replication was confirmed by depleting MCMs and assaying transient and long-term maintenance of the viral episomes. The recruitment of MCMs to the replication origins through LANA was demonstrated through chromatin immunoprecipitation and isolation of proteins on nascent replicated DNA (iPOND). These data clearly show the role of MCMs in latent DNA replication and the potential for targeting the C-terminal domain of LANA to block viral persistence.IMPORTANCE LANA-mediated latent DNA replication is essential for efficient maintenance of KSHV episomes in the host. During latency, virus relies on the host cellular machinery for replication, which occurs in synchrony with the cellular DNA. LANA interacts with the components of multiple cellular pathways, including cellular replication machinery, and recruits them to the viral origin for DNA replication. In this study, we characterize the interactions between LANA and minichromosome maintenance (MCM) proteins, members of the cellular replication complex. We demonstrated a cell cycle-dependent interaction between LANA and MCMs and determined their importance for viral genome replication and maintenance through biochemical assays. In addition, we mapped a 50-amino acid region in LANA which was capable of abrogating the association of MCM6 with LANA and blocking DNA replication. We also detected LANA along with MCMs at the replication forks using a novel approach, isolation of proteins on nascent DNA (iPOND).
Collapse
|
13
|
Kaposi's Sarcoma-Associated Herpesvirus LANA-Adjacent Regions with Distinct Functions in Episome Segregation or Maintenance. J Virol 2019; 93:JVI.02158-18. [PMID: 30626680 PMCID: PMC6401465 DOI: 10.1128/jvi.02158-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/02/2019] [Indexed: 12/16/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) is a 1,162-amino-acid protein that mediates episome persistence of viral genomes. LANA binds the KSHV terminal-repeat (TR) sequence through its carboxy-terminal domain to mediate DNA replication. LANA simultaneously binds mitotic chromosomes and TR DNA to segregate virus genomes to daughter cell nuclei. Amino-terminal LANA attaches to chromosomes by binding histones H2A/H2B, and carboxy-terminal LANA contributes to mitotic-chromosome binding. Although amino- and carboxy-terminal LANA are essential for episome persistence, they are not sufficient, since deletion of all internal LANA sequence renders LANA highly deficient for episome maintenance. Internal LANA sequence upstream of the internal repeat elements contributes to episome segregation and persistence. Here, we investigate this region with a panel of LANA deletion mutants. Mutants retained the ability to associate with mitotic chromosomes and bind TR DNA. In contrast to prior results, deletion of most of this sequence did not reduce LANA's ability to mediate DNA replication. Deletions of upstream sequence within the region compromised segregation of TR DNA to daughter cells, as assessed by retention of green fluorescent protein (GFP) expression from a replication-deficient TR plasmid. However, deletion of this upstream sequence did not reduce episome maintenance. In contrast, deletions that included an 80-amino-acid sequence immediately downstream resulted in highly deficient episome persistence. LANA with this downstream sequence deleted maintained the ability to replicate and segregate TR DNA, suggesting a unique role for the residues. Therefore, this work identifies adjacent LANA regions with distinct roles in episome segregation and persistence.IMPORTANCE KSHV LANA mediates episomal persistence of viral genomes. LANA binds the KSHV terminal-repeat (TR) sequence to mediate DNA replication and tethers KSHV DNA to mitotic chromosomes to segregate genomes to daughter cell nuclei. Here, we investigate LANA sequence upstream of the internal repeat elements that contributes to episome segregation and persistence. Mutants with deletions within this sequence maintained the ability to bind mitotic chromosomes or bind and replicate TR DNA. Deletion of upstream sequence within the region reduced segregation of TR DNA to daughter cells, but not episome maintenance. In contrast, mutants with deletions of 80 amino acids immediately downstream were highly deficient for episome persistence yet maintained the ability to replicate and segregate TR DNA, the two principal components of episome persistence, suggesting another role for the residues. In summary, this work identifies adjacent LANA sequence with distinct roles in episome segregation and persistence.
Collapse
|
14
|
Zhang F, Liang D, Lin X, Zou Z, Sun R, Wang X, Liang X, Kaye KM, Lan K. NDRG1 facilitates the replication and persistence of Kaposi's sarcoma-associated herpesvirus by interacting with the DNA polymerase clamp PCNA. PLoS Pathog 2019; 15:e1007628. [PMID: 30811506 PMCID: PMC6411202 DOI: 10.1371/journal.ppat.1007628] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/11/2019] [Accepted: 02/08/2019] [Indexed: 02/07/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) latently infects host cells and establishes lifelong persistence as an extra-chromosomal episome in the nucleus. To persist in proliferating cells, the viral genome typically replicates once per cell cycle and is distributed into daughter cells. This process involves host machinery utilized by KSHV, however the underlying mechanisms are not fully elucidated. In present study, we found that N-Myc downstream regulated gene 1 (NDRG1), a cellular gene known to be non-detectable in primary B cells and endothelial cells which are the major cell types for KSHV infection in vivo, was highly upregulated by KSHV in these cells. We further demonstrated that the high expression of NDRG1 was regulated by latency-associated nuclear antigen (LANA), the major viral latent protein which tethers the viral genome to host chromosome and plays an essential role in viral genome maintenance. Surprisingly, knockdown of NDRG1 in KSHV latently infected cells resulted in a significant decrease of viral genome copy number in these cells. Interestingly, NDRG1 can directly interact with proliferating cell nuclear antigen (PCNA), a cellular protein which functions as a DNA polymerase clamp during DNA replication. Intriguingly, we found that NDRG1 forms a complex with LANA and PCNA and serves as a scaffold protein bridging these two proteins. We further demonstrated that NDRG1 is critical for mediating LANA to recruit PCNA onto terminal repeat (TR) of KSHV genome, and facilitates viral DNA replication and episome persistence. Taken together, our findings suggest that NDRG1 plays an important role in KSHV viral genome replication, and provide new clues for understanding of KSHV persistence.
Collapse
Affiliation(s)
- Fang Zhang
- CAS Key Laboratory of Molecular Virology & Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Deguang Liang
- CAS Key Laboratory of Molecular Virology & Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Xiaoxi Lin
- CAS Key Laboratory of Molecular Virology & Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Zhe Zou
- CAS Key Laboratory of Molecular Virology & Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Rui Sun
- CAS Key Laboratory of Molecular Virology & Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Xing Wang
- CAS Key Laboratory of Molecular Virology & Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Xiaozhen Liang
- CAS Key Laboratory of Molecular Virology & Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Kenneth M. Kaye
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, United States of America
| | - Ke Lan
- State Key Laboratory of Virology, College of Life Sciences, Medical Research Institute, Wuhan University, Wuhan, China
- * E-mail:
| |
Collapse
|
15
|
Sorel O, Dewals BG. The Critical Role of Genome Maintenance Proteins in Immune Evasion During Gammaherpesvirus Latency. Front Microbiol 2019; 9:3315. [PMID: 30687291 PMCID: PMC6333680 DOI: 10.3389/fmicb.2018.03315] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/20/2018] [Indexed: 12/25/2022] Open
Abstract
Gammaherpesviruses are important pathogens that establish latent infection in their natural host for lifelong persistence. During latency, the viral genome persists in the nucleus of infected cells as a circular episomal element while the viral gene expression program is restricted to non-coding RNAs and a few latency proteins. Among these, the genome maintenance protein (GMP) is part of the small subset of genes expressed in latently infected cells. Despite sharing little peptidic sequence similarity, gammaherpesvirus GMPs have conserved functions playing essential roles in latent infection. Among these functions, GMPs have acquired an intriguing capacity to evade the cytotoxic T cell response through self-limitation of MHC class I-restricted antigen presentation, further ensuring virus persistence in the infected host. In this review, we provide an updated overview of the main functions of gammaherpesvirus GMPs during latency with an emphasis on their immune evasion properties.
Collapse
Affiliation(s)
- Océane Sorel
- Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine-FARAH, University of Liège, Liège, Belgium.,Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA, United States
| | - Benjamin G Dewals
- Immunology-Vaccinology, Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine-FARAH, University of Liège, Liège, Belgium
| |
Collapse
|
16
|
Habison AC, de Miranda MP, Beauchemin C, Tan M, Cerqueira SA, Correia B, Ponnusamy R, Usherwood EJ, McVey CE, Simas JP, Kaye KM. Cross-species conservation of episome maintenance provides a basis for in vivo investigation of Kaposi's sarcoma herpesvirus LANA. PLoS Pathog 2017; 13:e1006555. [PMID: 28910389 PMCID: PMC5599060 DOI: 10.1371/journal.ppat.1006555] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/27/2017] [Indexed: 12/26/2022] Open
Abstract
Many pathogens, including Kaposi's sarcoma herpesvirus (KSHV), lack tractable small animal models. KSHV persists as a multi-copy, nuclear episome in latently infected cells. KSHV latency-associated nuclear antigen (kLANA) binds viral terminal repeat (kTR) DNA to mediate episome persistence. Model pathogen murine gammaherpesvirus 68 (MHV68) mLANA acts analogously on mTR DNA. kLANA and mLANA differ substantially in size and kTR and mTR show little sequence conservation. Here, we find kLANA and mLANA act reciprocally to mediate episome persistence of TR DNA. Further, kLANA rescued mLANA deficient MHV68, enabling a chimeric virus to establish latent infection in vivo in germinal center B cells. The level of chimeric virus in vivo latency was moderately reduced compared to WT infection, but WT or chimeric MHV68 infected cells had similar viral genome copy numbers as assessed by immunofluorescence of LANA intranuclear dots or qPCR. Thus, despite more than 60 Ma of evolutionary divergence, mLANA and kLANA act reciprocally on TR DNA, and kLANA functionally substitutes for mLANA, allowing kLANA investigation in vivo. Analogous chimeras may allow in vivo investigation of genes of other human pathogens.
Collapse
Affiliation(s)
- Aline C. Habison
- Departments of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marta Pires de Miranda
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Chantal Beauchemin
- Departments of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Min Tan
- Departments of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sofia A. Cerqueira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Bruno Correia
- Instituto de Tecnologia Quimica e Bioliogica Antonio Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Rajesh Ponnusamy
- Instituto de Tecnologia Quimica e Bioliogica Antonio Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Edward J. Usherwood
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, United States of America
| | - Colin E. McVey
- Instituto de Tecnologia Quimica e Bioliogica Antonio Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - J. Pedro Simas
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- * E-mail: (KMK); (JPS)
| | - Kenneth M. Kaye
- Departments of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (KMK); (JPS)
| |
Collapse
|
17
|
Chiu YF, Sugden AU, Fox K, Hayes M, Sugden B. Kaposi's sarcoma-associated herpesvirus stably clusters its genomes across generations to maintain itself extrachromosomally. J Cell Biol 2017; 216:2745-2758. [PMID: 28696226 PMCID: PMC5584176 DOI: 10.1083/jcb.201702013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/23/2017] [Accepted: 05/31/2017] [Indexed: 02/08/2023] Open
Abstract
Genetic elements that replicate extrachromosomally are rare in mammals; however, several human tumor viruses, including the papillomaviruses and the gammaherpesviruses, maintain their plasmid genomes by tethering them to cellular chromosomes. We have uncovered an unprecedented mechanism of viral replication: Kaposi's sarcoma-associated herpesvirus (KSHV) stably clusters its genomes across generations to maintain itself extrachromosomally. To identify and characterize this mechanism, we developed two complementary, independent approaches: live-cell imaging and a predictive computational model. The clustering of KSHV requires the viral protein, LANA1, to bind viral genomes to nucleosomes arrayed on both cellular and viral DNA. Clustering affects both viral partitioning and viral genome numbers of KSHV. The clustering of KSHV plasmids provides it with an effective evolutionary strategy to rapidly increase copy numbers of genomes per cell at the expense of the total numbers of cells infected.
Collapse
MESH Headings
- Antigens, Viral/genetics
- Antigens, Viral/metabolism
- Chromosomes
- Computer Simulation
- DNA Replication
- DNA, Viral/biosynthesis
- DNA, Viral/genetics
- Evolution, Molecular
- Gene Expression Regulation, Viral
- Genome, Viral
- Genomic Instability
- HEK293 Cells
- HeLa Cells
- Herpesvirus 4, Human/genetics
- Herpesvirus 8, Human/genetics
- Herpesvirus 8, Human/growth & development
- Herpesvirus 8, Human/metabolism
- Host-Pathogen Interactions
- Humans
- In Situ Hybridization, Fluorescence
- Microscopy, Confocal
- Microscopy, Video
- Models, Genetic
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Protein Binding
- Time Factors
- Time-Lapse Imaging
- Transfection
- Virus Replication
Collapse
Affiliation(s)
- Ya-Fang Chiu
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI
- Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI
- Research Center for Emerging Viral Infections, Chang-Gung University, Taoyuan, Taiwan
- Department of Microbiology and Immunology, Chang-Gung University, Taoyuan, Taiwan
- Department of Medical Laboratory, Chang-Gung Memorial Hospital, Taoyuan, Taiwan
| | - Arthur U Sugden
- Department of Neuroscience, Brown University, Providence, RI
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
| | - Kathryn Fox
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI
- Flow Cytometry Laboratory, Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI
| | - Mitchell Hayes
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI
| | - Bill Sugden
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI
| |
Collapse
|
18
|
Howard K, Cherezova L, DeMaster LK, Rose TM. ORF73 LANA homologs of RRV and MneRV2 contain an extended RGG/RG-rich nuclear and nucleolar localization signal that interacts directly with importin β1 for non-classical nuclear import. Virology 2017; 511:152-164. [PMID: 28850829 DOI: 10.1016/j.virol.2017.08.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/10/2017] [Accepted: 08/22/2017] [Indexed: 01/26/2023]
Abstract
The latency-associated nuclear antigens (LANA) of KSHV and macaque RFHVMn, members of the RV1 rhadinovirus lineage, are closely related with conservation of complex nuclear localization signals (NLS) containing bipartite KR-rich motifs and RG-rich domains, which interact distinctly with importins α and ß1 for nuclear import via classical and non-classical pathways, respectively. RV1 LANAs are expressed in the nucleus of latently-infected cells where they inhibit replication and establish a dominant RV1 latency. Here we show that LANA homologs of macaque RRV and MneRV2 from the more distantly-related RV2 lineage, lack the KR-rich NLS, and instead have a large RG-rich NLS with multiple RG dipeptides and a conserved RGG motif. The RG-NLS interacts uniquely with importin β1, which mediates nuclear import and accumulation of RV2 LANA in the nucleolus. The alternative nuclear import and localization of RV2 LANA homologs may contribute to the dominant RV2 lytic replication phenotype.
Collapse
Affiliation(s)
- Kellie Howard
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA.
| | - Lidia Cherezova
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA
| | - Laura K DeMaster
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA.
| | - Timothy M Rose
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA.
| |
Collapse
|
19
|
Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen: Replicating and Shielding Viral DNA during Viral Persistence. J Virol 2017; 91:JVI.01083-16. [PMID: 28446671 DOI: 10.1128/jvi.01083-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Kaposi's sarcoma herpesvirus (KSHV) establishes lifelong latency. The viral latency-associated nuclear antigen (LANA) promotes viral persistence by tethering the viral genome to cellular chromosomes and by participating in latent DNA replication. Recently, the structure of the LANA C-terminal DNA binding domain was solved and new cytoplasmic variants of LANA were discovered. We discuss how these findings contribute to our current view of LANA structure and assembly and of its role during viral persistence.
Collapse
|
20
|
Rowley PA. The frenemies within: viruses, retrotransposons and plasmids that naturally infect Saccharomyces yeasts. Yeast 2017; 34:279-292. [PMID: 28387035 DOI: 10.1002/yea.3234] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 11/07/2022] Open
Abstract
Viruses are a major focus of current research efforts because of their detrimental impact on humanity and their ubiquity within the environment. Bacteriophages have long been used to study host-virus interactions within microbes, but it is often forgotten that the single-celled eukaryote Saccharomyces cerevisiae and related species are infected with double-stranded RNA viruses, single-stranded RNA viruses, LTR-retrotransposons and double-stranded DNA plasmids. These intracellular nucleic acid elements have some similarities to higher eukaryotic viruses, i.e. yeast retrotransposons have an analogous lifecycle to retroviruses, the particle structure of yeast totiviruses resembles the capsid of reoviruses and segregation of yeast plasmids is analogous to segregation strategies used by viral episomes. The powerful experimental tools available to study the genetics, cell biology and evolution of S. cerevisiae are well suited to further our understanding of how cellular processes are hijacked by eukaryotic viruses, retrotransposons and plasmids. This article has been written to briefly introduce viruses, retrotransposons and plasmids that infect Saccharomyces yeasts, emphasize some important cellular proteins and machineries with which they interact, and suggest the evolutionary consequences of these interactions. Copyright © 2017 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Paul A Rowley
- Department of Biological Sciences, The University of Idaho, Moscow, Idaho, USA
| |
Collapse
|
21
|
A central region in the minor capsid protein of papillomaviruses facilitates viral genome tethering and membrane penetration for mitotic nuclear entry. PLoS Pathog 2017; 13:e1006308. [PMID: 28464022 PMCID: PMC5412989 DOI: 10.1371/journal.ppat.1006308] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/22/2017] [Indexed: 12/18/2022] Open
Abstract
Incoming papillomaviruses (PVs) depend on mitotic nuclear envelope breakdown to gain initial access to the nucleus for viral transcription and replication. In our previous work, we hypothesized that the minor capsid protein L2 of PVs tethers the incoming vDNA to mitotic chromosomes to direct them into the nascent nuclei. To re-evaluate how dynamic L2 recruitment to cellular chromosomes occurs specifically during prometaphase, we developed a quantitative, microscopy-based assay for measuring the degree of chromosome recruitment of L2-EGFP. Analyzing various HPV16 L2 truncation-mutants revealed a central chromosome-binding region (CBR) of 147 amino acids that confers binding to mitotic chromosomes. Specific mutations of conserved motifs (IVAL286AAAA, RR302/5AA, and RTR313EEE) within the CBR interfered with chromosomal binding. Moreover, assembly-competent HPV16 containing the chromosome-binding deficient L2(RTR313EEE) or L2(IVAL286AAAA) were inhibited for infection despite their ability to be transported to intracellular compartments. Since vDNA and L2 were not associated with mitotic chromosomes either, the infectivity was likely impaired by a defect in tethering of the vDNA to mitotic chromosomes. However, L2 mutations that abrogated chromatin association also compromised translocation of L2 across membranes of intracellular organelles. Thus, chromatin recruitment of L2 may in itself be a requirement for successful penetration of the limiting membrane thereby linking both processes mechanistically. Furthermore, we demonstrate that the association of L2 with mitotic chromosomes is conserved among the alpha, beta, gamma, and iota genera of Papillomaviridae. However, different binding patterns point to a certain variance amongst the different genera. Overall, our data suggest a common strategy among various PVs, in which a central region of L2 mediates tethering of vDNA to mitotic chromosomes during cell division thereby coordinating membrane translocation and delivery to daughter nuclei. Papillomaviruses can cause carcinogenic malignancies such as cervical cancer. Like most DNA viruses, papillomaviruses must deliver their genome to the cell nucleus during initial infection, where it is expressed and replicated. However, papillomaviruses make use of unconventional mechanisms for genome delivery. They reside on the cell surface for protracted, hour-long times, before they are taken up by a novel endocytic mechanism. Moreover, they are delivered to the trans-Golgi-network by non-canonical endosomal trafficking prior to nuclear delivery. For entry into the nucleus, papillomaviruses access the nuclear space after nuclear envelope breakdown during mitosis unlike most other intranuclear viruses. The detailed mechanism how the viral genome is directed to nascent nuclei during mitosis remains elusive. Our previous work suggested that the minor capsid protein L2 may tether the incoming viral genome to mitotic chromosomes to direct it to the nascent nuclei. This work identifies a conserved central region in L2 protein to be necessary and sufficient for tethering. Moreover, it demonstrates that this mechanism is conserved across different papillomavirus genera. Importantly, this report also provides evidence that the processes of nuclear import by tethering and membrane penetration are mechanistically linked.
Collapse
|
22
|
Auten M, Kim AS, Bradley KT, Rosado FG. Human herpesvirus 8-related diseases: Histopathologic diagnosis and disease mechanisms. Semin Diagn Pathol 2017; 34:371-376. [PMID: 28502522 DOI: 10.1053/j.semdp.2017.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The emergence of HIV/AIDS more than three decades ago led to an increased incidence of diseases caused by HHV8 co-infection, particularly Kaposi sarcoma, primary effusion lymphoma, and multicentric Castleman disease. Over time, the development of highly effective AIDS therapies has resulted in a decreased incidence of HHV8-associated entities, which are now more commonly found in patients with undiagnosed and/or untreated AIDS. Due to their rarity, some of these diseases may be difficult to recognize without appropriate clinical information. This article provides an overview of HHV8-related disorders, with a focus on their morphologic and phenotypic features, and includes a brief overview of laboratory methods used to detect HHV8. Disease mechanisms by which the HHV8 virion promotes tumorigenesis are also reviewed.
Collapse
Affiliation(s)
- Matthew Auten
- Department of Pathology, West Virginia University, United States.
| | - Annette S Kim
- Department of Pathology, Brigham and Women's Hospital, United States.
| | - Kyle T Bradley
- Department of Pathology & Laboratory Medicine, Emory University Hospital, 1364 Clifton Rd NE, Atlanta, GA 30322, United States.
| | - Flavia G Rosado
- Department of Pathology, West Virginia University, 1 Medical Center Dr, Room 2146F/HSC North, United States.
| |
Collapse
|
23
|
The Viral Bcl-2 Homologs of Kaposi's Sarcoma-Associated Herpesvirus and Rhesus Rhadinovirus Share an Essential Role for Viral Replication. J Virol 2017; 91:JVI.01875-16. [PMID: 28053098 PMCID: PMC5331788 DOI: 10.1128/jvi.01875-16] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/23/2016] [Indexed: 01/07/2023] Open
Abstract
KS-Bcl-2 is a Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded viral Bcl-2 (vBcl-2) homolog which has apoptosis- and autophagy-inhibiting activity when expressed in transfected cells. However, little is known about its function during viral infection. As KS-Bcl-2 is expressed during the lytic replication cycle, we used constitutively lytic and inducibly lytic KSHV mutants to investigate the role of KS-Bcl-2 during the lytic cycle. We show that KSHV cannot complete the lytic replication cycle and produce infectious progeny in the absence of KS-Bcl-2, indicating that the protein is essential for KSHV replication. Replacement of the KS-Bcl-2 coding sequence, ORF16, by sequences encoding a potent cellular apoptosis and autophagy inhibitor, Bcl-XL, or the cytomegalovirus mitochondrial inhibitor of apoptosis, vMIA, did not rescue KSHV replication, suggesting that KS-Bcl-2 has a function that goes beyond apoptosis and autophagy inhibition. Strikingly, the vBcl-2 proteins of the related γ2-herpesviruses murine herpesvirus 68 and herpesvirus saimiri did not rescue the replication of a KS-Bcl-2 deletion mutant, but rhesus rhadinovirus (RRV) vBcl-2 did. Deletion of ORF16 from the RRV genome abrogated viral replication, but its replacement by KSHV ORF16 rescued RRV replication, indicating that the essential vBcl-2 function is conserved between these two primate rhadinoviruses. We further show that the KSHV and RRV Bcl-2 homologs localize to the mitochondria and nuclei of infected cells. Deletion of 17 amino acids from the N terminus of KS-Bcl-2 abrogates nuclear localization and KSHV replication, suggesting that KS-Bcl-2 might execute its essential function in the nuclei of infected cells.IMPORTANCE Several viruses express proteins homologous to cellular Bcl-2. Viral Bcl-2 proteins have functions similar to those of cellular Bcl-2: they can inhibit apoptosis, a form of programmed cell death, and autophagy, a self-degradative process for the disposal of dysfunctional or unwanted components. This study shows that the vBcl-2 proteins of KSHV and RRV differ from other vBcl-2 proteins in that they are essential for viral replication. The essential function is separate from the apoptosis- and autophagy-inhibiting activity but correlates with an unusual localization within the cell nucleus, suggesting that these proteins exert a novel function in the nucleus.
Collapse
|
24
|
Repression of the Chromatin-Tethering Domain of Murine Leukemia Virus p12. J Virol 2016; 90:11197-11207. [PMID: 27707926 DOI: 10.1128/jvi.01084-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 09/28/2016] [Indexed: 12/28/2022] Open
Abstract
Murine leukemia virus (MLV) p12, encoded within Gag, binds the viral preintegration complex (PIC) to the mitotic chromatin. This acts to anchor the viral PIC in the nucleus as the nuclear envelope re-forms postmitosis. Mutations within the p12 C terminus (p12 PM13 to PM15) block early stages in viral replication. Within the p12 PM13 region (p12 60PSPMA65), our studies indicated that chromatin tethering was not detected when the wild-type (WT) p12 protein (M63) was expressed as a green fluorescent protein (GFP) fusion; however, constructs bearing p12-I63 were tethered. N-terminal truncations of the activated p12-I63-GFP indicated that tethering increased further upon deletion of p12 25DLLTEDPPPY34, which includes the late domain required for viral assembly. The p12 PM15 sequence (p12 70RREPP74) is critical for wild-type viral viability; however, virions bearing the PM15 mutation (p12 70AAAAA74) with a second M63I mutant were viable, with a titer 18-fold lower than that of the WT. The p12 M63I mutation amplified chromatin tethering and compensated for the loss of chromatin binding of p12 PM15. Rescue of the p12-M63-PM15 nonviable mutant with prototype foamy virus (PFV) and Kaposi's sarcoma herpesvirus (KSHV) tethering sequences confirmed the function of p1270-74 in chromatin binding. Minimally, full-strength tethering was seen with only p12 61SPIASRLRGRR71 fused to GFP. These results indicate that the p12 C terminus alone is sufficient for chromatin binding and that the presence of the p12 25DLLTEDPPPY34 motif in the N terminus suppresses the ability to tether. IMPORTANCE This study defines a regulatory mechanism controlling the differential roles of the MLV p12 protein in early and late replication. During viral assembly and egress, the late domain within the p12 N terminus functions to bind host vesicle release factors. During viral entry, the C terminus of p12 is required for tethering to host mitotic chromosomes. Our studies indicate that the p12 domain including the PPPY late sequence temporally represses the p12 chromatin tethering motif. Maximal p12 tethering was identified with only an 11-amino-acid minimal chromatin tethering motif encoded at p1261-71 Within this region, the p12-M63I substitution switches p12 into a tethering-competent state, partially rescuing the p12-PM15 tethering mutant. A model for how this conformational change regulates early versus late functions is presented.
Collapse
|
25
|
Reed A, Lin L, Ostertag-Hill C, Wang Q, Wu Z, Miller-Morgan T, Jin L. Detection of ORF6 protein associated with latent KHV infection. Virology 2016; 500:82-90. [PMID: 27771562 DOI: 10.1016/j.virol.2016.09.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/28/2016] [Accepted: 09/29/2016] [Indexed: 11/28/2022]
Abstract
Koi herpesvirus (KHV) is highly pathogenic to Cyprinus carpio. KHV can also become latent in recovered fish and reactivate from latency under stressful conditions. Understanding KHV latency is important for development of strategies against herpesvirus latent infection. Our previous studies found KHV ORF6 mRNA is detectable during latent infection. In this study, ORF6 protein expression was investigated by a polyclonal antibody specific to ORF6 peptide. Positive staining by an immunofluorescence assay was observed in both KHV infected CCB (common carp brain) cells and IgM+ white blood cells (WBCs) from recovered KHV+ koi. Proteins at the expected size, 68kDa, and several different sizes can be detected during productive infection. Five potential sumoylation sites were identified in the ORF6 protein. Our study demonstrated that ORF6 protein is expressed in both productive infection and latent infection and may have different post-translational modifications during productive infection.
Collapse
Affiliation(s)
- Aimee Reed
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University Corvallis, OR 97331, USA; Department of Microbiology, College of Science, Oregon State University, Corvallis, OR 97331, USA
| | - Lisa Lin
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University Corvallis, OR 97331, USA
| | - Claire Ostertag-Hill
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University Corvallis, OR 97331, USA
| | - Qing Wang
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University Corvallis, OR 97331, USA
| | - Zhixing Wu
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University Corvallis, OR 97331, USA
| | - Tim Miller-Morgan
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University Corvallis, OR 97331, USA; Aquatic Animal Health Program, Oregon Sea Grant, Hatfield Marine Science Center, Oregon State University, Newport, OR 97365, USA
| | - Ling Jin
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University Corvallis, OR 97331, USA; Department of Microbiology, College of Science, Oregon State University, Corvallis, OR 97331, USA.
| |
Collapse
|
26
|
Latency-Associated Nuclear Antigen E3 Ubiquitin Ligase Activity Impacts Gammaherpesvirus-Driven Germinal Center B Cell Proliferation. J Virol 2016; 90:7667-83. [PMID: 27307564 DOI: 10.1128/jvi.00813-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 06/06/2016] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED Viruses have evolved mechanisms to hijack components of cellular E3 ubiquitin ligases, thus modulating the ubiquitination pathway. However, the biological relevance of such mechanisms for viral pathogenesis in vivo remains largely unknown. Here, we utilized murid herpesvirus 4 (MuHV-4) infection of mice as a model system to address the role of MuHV-4 latency-associated nuclear antigen (mLANA) E3 ligase activity in gammaherpesvirus latent infection. We show that specific mutations in the mLANA SOCS box (V199A, V199A/L202A, or P203A/P206A) disrupted mLANA's ability to recruit Elongin C and Cullin 5, thereby impairing the formation of the Elongin BC/Cullin 5/SOCS (EC5S(mLANA)) complex and mLANA's E3 ligase activity on host NF-κB and Myc. Although these mutations resulted in considerably reduced mLANA binding to viral terminal repeat DNA as assessed by electrophoretic mobility shift assay (EMSA), the mutations did not disrupt mLANA's ability to mediate episome persistence. In vivo, MuHV-4 recombinant viruses bearing these mLANA SOCS box mutations exhibited a deficit in latency amplification in germinal center (GC) B cells. These findings demonstrate that the E3 ligase activity of mLANA contributes to gammaherpesvirus-driven GC B cell proliferation. Hence, pharmacological inhibition of viral E3 ligase activity through targeting SOCS box motifs is a putative strategy to control gammaherpesvirus-driven lymphoproliferation and associated disease. IMPORTANCE The gammaherpesviruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) cause lifelong persistent infection and play causative roles in several human malignancies. Colonization of B cells is crucial for virus persistence, and access to the B cell compartment is gained by virus-driven proliferation in germinal center (GC) B cells. Infection of B cells is predominantly latent, with the viral genome persisting as a multicopy episome and expressing only a small subset of viral genes. Here, we focused on latency-associated nuclear antigen (mLANA) encoded by murid herpesvirus-4 (MuHV-4), which exhibits homology in sequence, structure, and function to KSHV LANA (kLANA), thereby allowing the study of LANA-mediated pathogenesis in mice. Our experiments show that mLANA's E3 ubiquitin ligase activity is necessary for efficient expansion of latency in GC B cells, suggesting that the development of pharmacological inhibitors of LANA E3 ubiquitin ligase activity may allow strategies to interfere with gammaherpesvirus-driven lymphoproliferation and associated disease.
Collapse
|
27
|
Juillard F, Tan M, Li S, Kaye KM. Kaposi's Sarcoma Herpesvirus Genome Persistence. Front Microbiol 2016; 7:1149. [PMID: 27570517 PMCID: PMC4982378 DOI: 10.3389/fmicb.2016.01149] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 07/11/2016] [Indexed: 12/17/2022] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) has an etiologic role in Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman’s disease. These diseases are most common in immunocompromised individuals, especially those with AIDS. Similar to all herpesviruses, KSHV infection is lifelong. KSHV infection in tumor cells is primarily latent, with only a small subset of cells undergoing lytic infection. During latency, the KSHV genome persists as a multiple copy, extrachromosomal episome in the nucleus. In order to persist in proliferating tumor cells, the viral genome replicates once per cell cycle and then segregates to daughter cell nuclei. KSHV only expresses several genes during latent infection. Prominent among these genes, is the latency-associated nuclear antigen (LANA). LANA is responsible for KSHV genome persistence and also exerts transcriptional regulatory effects. LANA mediates KSHV DNA replication and in addition, is responsible for segregation of replicated genomes to daughter nuclei. LANA serves as a molecular tether, bridging the viral genome to mitotic chromosomes to ensure that KSHV DNA reaches progeny nuclei. N-terminal LANA attaches to mitotic chromosomes by binding histones H2A/H2B at the surface of the nucleosome. C-terminal LANA binds specific KSHV DNA sequence and also has a role in chromosome attachment. In addition to the essential roles of N- and C-terminal LANA in genome persistence, internal LANA sequence is also critical for efficient episome maintenance. LANA’s role as an essential mediator of virus persistence makes it an attractive target for inhibition in order to prevent or treat KSHV infection and disease.
Collapse
Affiliation(s)
- Franceline Juillard
- Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School Boston, MA, USA
| | - Min Tan
- Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School Boston, MA, USA
| | - Shijun Li
- Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School Boston, MA, USA
| | - Kenneth M Kaye
- Departments of Medicine, Brigham and Women's Hospital, Harvard Medical School Boston, MA, USA
| |
Collapse
|
28
|
Aydin I, Schelhaas M. Viral Genome Tethering to Host Cell Chromatin: Cause and Consequences. Traffic 2016; 17:327-40. [PMID: 26787361 DOI: 10.1111/tra.12378] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 01/14/2016] [Accepted: 01/14/2016] [Indexed: 12/26/2022]
Abstract
Viruses are small infectious agents that replicate in cells of a host organism and that evolved to use cellular machineries for all stages of the viral life cycle. Here, we critically assess current knowledge on a particular mechanism of persisting viruses, namely, how they tether their genomes to host chromatin, and what consequences arise from this process. A group of persisting DNA viruses, i.e. gamma-herpesviruses and papillomaviruses (PV), uses this tethering strategy to maintain their genomes in the nuclei during cell division. Thus, these viruses face the challenge of viral genome loss during mitosis, as they are transported with the host chromosomes to the nascent daughter nuclei. Incidentally, another group of viruses, certain retroviruses and PV, have adopted this tethering strategy to deliver their genomes into the nuclei of dividing cells during cell entry. By exploiting a phase in the cell cycle when the nuclear envelope is disassembled, viruses bypass the need to engage with the nuclear import machinery. Recent reports suggest that tethering may induce severe cellular consequences that involve activation of mitotic checkpoints, causing missegregation of host chromosomes and genomic instability, which may contribute to cancer.
Collapse
Affiliation(s)
- Inci Aydin
- Cell Biology of Virus Infection Unit, Institutes of Molecular Virology and Medical Biochemistry, ZMBE, University of Münster, Münster, Germany.,Cells in Motion, CiM, Cluster of Excellence EXC 1003, Münster, Germany
| | - Mario Schelhaas
- Cell Biology of Virus Infection Unit, Institutes of Molecular Virology and Medical Biochemistry, ZMBE, University of Münster, Münster, Germany.,Cells in Motion, CiM, Cluster of Excellence EXC 1003, Münster, Germany
| |
Collapse
|
29
|
Cytoplasmic isoforms of Kaposi sarcoma herpesvirus LANA recruit and antagonize the innate immune DNA sensor cGAS. Proc Natl Acad Sci U S A 2016; 113:E1034-43. [PMID: 26811480 DOI: 10.1073/pnas.1516812113] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The latency-associated nuclear antigen (LANA) of Kaposi sarcoma herpesvirus (KSHV) is mainly localized and functions in the nucleus of latently infected cells, playing a pivotal role in the replication and maintenance of latent viral episomal DNA. In addition, N-terminally truncated cytoplasmic isoforms of LANA, resulting from internal translation initiation, have been reported, but their function is unknown. Using coimmunoprecipitation and MS, we found the cGMP-AMP synthase (cGAS), an innate immune DNA sensor, to be a cellular interaction partner of cytoplasmic LANA isoforms. By directly binding to cGAS, LANA, and particularly, a cytoplasmic isoform, inhibit the cGAS-STING-dependent phosphorylation of TBK1 and IRF3 and thereby antagonize the cGAS-mediated restriction of KSHV lytic replication. We hypothesize that cytoplasmic forms of LANA, whose expression increases during lytic replication, inhibit cGAS to promote the reactivation of the KSHV from latency. This observation points to a novel function of the cytoplasmic isoforms of LANA during lytic replication and extends the function of LANA from its role during latency to the lytic replication cycle.
Collapse
|
30
|
Ponnusamy R, Petoukhov MV, Correia B, Custodio TF, Juillard F, Tan M, Pires de Miranda M, Carrondo MA, Simas JP, Kaye KM, Svergun DI, McVey CE. KSHV but not MHV-68 LANA induces a strong bend upon binding to terminal repeat viral DNA. Nucleic Acids Res 2015; 43:10039-54. [PMID: 26424851 PMCID: PMC4787769 DOI: 10.1093/nar/gkv987] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/16/2015] [Indexed: 12/20/2022] Open
Abstract
Latency-associated nuclear antigen (LANA) is central to episomal tethering, replication and transcriptional regulation of γ2-herpesviruses. LANA binds cooperatively to the terminal repeat (TR) region of the viral episome via adjacent LANA binding sites (LBS), but the molecular mechanism by which LANA assembles on the TR remains elusive. We show that KSHV LANA and MHV-68 LANA proteins bind LBS DNA using strikingly different modes. Solution structure of LANA complexes revealed that while kLANA tetramer is intrinsically bent both in the free and bound state to LBS1-2 DNA, mLANA oligomers instead adopt a rigid linear conformation. In addition, we report a novel non-ring kLANA structure that displays more flexibility at its assembly interface than previously demonstrated. We identified a hydrophobic pivot point located at the dimer-dimer assembly interface, which gives rotational freedom for kLANA to adopt variable conformations to accommodate both LBS1-2 and LBS2-1-3 DNA. Alterations in the arrangement of LBS within TR or at the tetramer assembly interface have a drastic effect on the ability of kLANA binding. We also show kLANA and mLANA DNA binding functions can be reciprocated. Although KSHV and MHV-68 are closely related, the findings provide new insights into how the structure, oligomerization, and DNA binding of LANA have evolved differently to assemble on the TR DNA.
Collapse
Affiliation(s)
- Rajesh Ponnusamy
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras 2700-157, Portugal
| | - Maxim V Petoukhov
- European Molecular Biology Laboratory, Hamburg Unit, EMBL c/o DESY, Hamburg 22607, Germany
| | - Bruno Correia
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras 2700-157, Portugal
| | - Tania F Custodio
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras 2700-157, Portugal
| | - Franceline Juillard
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Min Tan
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Marta Pires de Miranda
- Instituto de Microbiologia e Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Maria A Carrondo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras 2700-157, Portugal
| | - J Pedro Simas
- Instituto de Microbiologia e Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa 1649-028, Portugal
| | - Kenneth M Kaye
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Dmitri I Svergun
- European Molecular Biology Laboratory, Hamburg Unit, EMBL c/o DESY, Hamburg 22607, Germany
| | - Colin E McVey
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras 2700-157, Portugal
| |
Collapse
|
31
|
Li S, Tan M, Juillard F, Ponnusamy R, Correia B, Simas JP, Carrondo MA, McVey CE, Kaye KM. The Kaposi Sarcoma Herpesvirus Latency-associated Nuclear Antigen DNA Binding Domain Dorsal Positive Electrostatic Patch Facilitates DNA Replication and Episome Persistence. J Biol Chem 2015; 290:28084-28096. [PMID: 26420481 DOI: 10.1074/jbc.m115.674622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Indexed: 12/15/2022] Open
Abstract
Kaposi sarcoma-associated herpesvirus (KSHV) has a causative role in several human malignancies. KSHV latency-associated nuclear antigen (LANA) mediates persistence of viral episomes in latently infected cells. LANA mediates KSHV DNA replication and segregates episomes to progeny nuclei. The structure of the LANA DNA binding domain was recently solved, revealing a positive electrostatic patch opposite the DNA binding surface, which is the site of BET protein binding. Here we investigate the functional role of the positive patch in LANA-mediated episome persistence. As expected, LANA mutants with alanine or glutamate substitutions in the central, peripheral, or lateral portions of the positive patch maintained the ability to bind DNA by EMSA. However, all of the substitution mutants were deficient for LANA DNA replication and episome maintenance. Mutation of the peripheral region generated the largest deficiencies. Despite these deficiencies, all positive patch mutants concentrated to dots along mitotic chromosomes in cells containing episomes, similar to LANA. The central and peripheral mutants, but not the lateral mutants, were reduced for BET protein interaction as assessed by co-immunoprecipitation. However, defects in BET protein binding were independent of episome maintenance function. Overall, the reductions in episome maintenance closely correlated with DNA replication deficiencies, suggesting that the replication defects account for the reduced episome persistence. Therefore, the electrostatic patch exerts a key role in LANA-mediated DNA replication and episome persistence and may act through a host cell partner(s) other than a BET protein or by inducing specific structures or complexes.
Collapse
Affiliation(s)
- Shijun Li
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115
| | - Min Tan
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115
| | - Franceline Juillard
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115
| | - Rajesh Ponnusamy
- Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - Bruno Correia
- Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - J Pedro Simas
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Maria A Carrondo
- Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - Colin E McVey
- Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - Kenneth M Kaye
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115.
| |
Collapse
|
32
|
Affiliation(s)
- Robert K McGinty
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Song Tan
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| |
Collapse
|
33
|
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8) is the etiologic agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. These cancers often occur in the context of immunosuppression, which has made KSHV-associated malignancies an increasing global health concern with the persistence of the AIDS epidemic. KSHV has also been linked to several acute inflammatory diseases. KSHV exists between a lytic and latent lifecycle, which allows the virus to transition between active replication and quiescent infection. KSHV encodes a number of proteins and small RNAs that are thought to inadvertently transform host cells while performing their functions of helping the virus persist in the infected host. KSHV also has an arsenal of components that aid the virus in evading the host immune response, which help the virus establish a successful lifelong infection. In this comprehensive chapter, we will discuss the diseases associated with KSHV infection, the biology of latent and lytic infection, and individual proteins and microRNAs that are known to contribute to host cell transformation and immune evasion.
Collapse
Affiliation(s)
- Louise Giffin
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
| |
Collapse
|
34
|
Kaposi's sarcoma-associated herpesvirus LANA recruits the DNA polymerase clamp loader to mediate efficient replication and virus persistence. Proc Natl Acad Sci U S A 2014; 111:11816-21. [PMID: 25071216 DOI: 10.1073/pnas.1404219111] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) latently infects tumor cells and persists as a multiple-copy, extrachromosomal, circular episome. To persist, the viral genome must replicate with each cell cycle. The KSHV latency-associated nuclear antigen (LANA) mediates viral DNA replication and persistence, but little is known regarding the underlying mechanisms. We find that LANA recruits replication factor C (RFC), the DNA polymerase clamp [proliferating cell nuclear antigen (PCNA)] loader, to drive DNA replication efficiently. Mutated LANA lacking RFC interaction was deficient for LANA-mediated DNA replication and episome persistence. RFC depletion had a negative impact on LANA's ability to replicate and maintain viral DNA in cells containing artificial KSHV episomes or in infected cells, leading to loss of virus. LANA substantially increased PCNA loading onto DNA in vitro and recruited RFC and PCNA to KSHV DNA in cells. These findings suggest that PCNA loading is a rate-limiting step in DNA replication that is incompatible with viral survival. LANA enhancement of PCNA loading permits efficient virus replication and persistence, revealing a previously unidentified mechanism for KSHV latency.
Collapse
|
35
|
Leung JW, Agarwal P, Canny MD, Gong F, Robison AD, Finkelstein IJ, Durocher D, Miller KM. Nucleosome acidic patch promotes RNF168- and RING1B/BMI1-dependent H2AX and H2A ubiquitination and DNA damage signaling. PLoS Genet 2014; 10:e1004178. [PMID: 24603765 PMCID: PMC3945288 DOI: 10.1371/journal.pgen.1004178] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 12/31/2013] [Indexed: 12/23/2022] Open
Abstract
Histone ubiquitinations are critical for the activation of the DNA damage response (DDR). In particular, RNF168 and RING1B/BMI1 function in the DDR by ubiquitinating H2A/H2AX on Lys-13/15 and Lys-118/119, respectively. However, it remains to be defined how the ubiquitin pathway engages chromatin to provide regulation of ubiquitin targeting of specific histone residues. Here we identify the nucleosome acid patch as a critical chromatin mediator of H2A/H2AX ubiquitination (ub). The acidic patch is required for RNF168- and RING1B/BMI1-dependent H2A/H2AXub in vivo. The acidic patch functions within the nucleosome as nucleosomes containing a mutated acidic patch exhibit defective H2A/H2AXub by RNF168 and RING1B/BMI1 in vitro. Furthermore, direct perturbation of the nucleosome acidic patch in vivo by the expression of an engineered acidic patch interacting viral peptide, LANA, results in defective H2AXub and RNF168-dependent DNA damage responses including 53BP1 and BRCA1 recruitment to DNA damage. The acidic patch therefore is a critical nucleosome feature that may serve as a scaffold to integrate multiple ubiquitin signals on chromatin to compose selective ubiquitinations on histones for DNA damage signaling.
Collapse
Affiliation(s)
- Justin W Leung
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Poonam Agarwal
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Marella D Canny
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Fade Gong
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Aaron D Robison
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Daniel Durocher
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Kyle M Miller
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| |
Collapse
|
36
|
Beauchemin C, Moerke NJ, Faloon P, Kaye KM. Assay Development and High-Throughput Screening for Inhibitors of Kaposi's Sarcoma-Associated Herpesvirus N-Terminal Latency-Associated Nuclear Antigen Binding to Nucleosomes. ACTA ACUST UNITED AC 2014; 19:947-58. [PMID: 24518064 DOI: 10.1177/1087057114520973] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 01/03/2014] [Indexed: 11/17/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) has a causative role in several human malignancies, especially in immunocompromised hosts. KSHV latently infects tumor cells and persists as an extrachromosomal episome (plasmid). KSHV latency-associated nuclear antigen (LANA) mediates KSHV episome persistence. LANA binds specific KSHV sequence to replicate viral DNA. In addition, LANA tethers KSHV genomes to mitotic chromosomes to efficiently segregate episomes to daughter nuclei after mitosis. N-terminal LANA (N-LANA) binds histones H2A and H2B to attach to chromosomes. Currently, there are no specific inhibitors of KSHV latent infection. To enable high-throughput screening (HTS) of inhibitors of N-LANA binding to nucleosomes, here we develop, miniaturize, and validate a fluorescence polarization (FP) assay that detects fluorophore-labeled N-LANA peptide binding to nucleosomes. We also miniaturize a counterscreen to identify DNA intercalators that nonspecifically inhibit N-LANA binding to nucleosomes, and also develop an enzyme-linked immunosorbent assay to assess N-LANA binding to nucleosomes in the absence of fluorescence. HTS of libraries containing more than 350,000 compounds identified multiple compounds that inhibited N-LANA binding to nucleosomes. No compounds survived all counterscreens, however. More complex small-molecule libraries will likely be necessary to identify specific inhibitors of N-LANA binding to histones H2A and H2B; these assays should prove useful for future screens.
Collapse
Affiliation(s)
- Chantal Beauchemin
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Nathan J Moerke
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Patrick Faloon
- Broad Institute, Center for the Science of Therapeutics, Therapeutics Platform, Cambridge, USA
| | - Kenneth M Kaye
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| |
Collapse
|
37
|
Abstract
Latent Kaposi's sarcoma-associated herpesvirus (KSHV) episomes are coated with viral latency-associated nuclear antigen (LANA). In contrast, LANA rapidly disassociates from episomes during reactivation. Lytic KSHV expresses polyadenylated nuclear RNA (PAN RNA), a long noncoding RNA (lncRNA). We report that PAN RNA promotes LANA-episome disassociation through an interaction with LANA which facilitates LANA sequestration away from KSHV episomes during reactivation. These findings suggest that KSHV may have evolved an RNA aptamer to regulate latent protein function.
Collapse
|
38
|
De León Vázquez E, Juillard F, Rosner B, Kaye KM. A short sequence immediately upstream of the internal repeat elements is critical for KSHV LANA mediated DNA replication and impacts episome persistence. Virology 2013; 448:344-55. [PMID: 24314665 DOI: 10.1016/j.virol.2013.10.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 08/12/2013] [Accepted: 10/18/2013] [Indexed: 02/06/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus LANA (1162 residues) mediates episomal persistence of viral genomes during latency. LANA mediates viral DNA replication and segregates episomes to daughter nuclei. A 59 residue deletion immediately upstream of the internal repeat elements rendered LANA highly deficient for DNA replication and modestly deficient for the ability to segregate episomes, while smaller deletions did not. The 59 amino acid deletion reduced LANA episome persistence by ~14-fold, while sequentially smaller deletions resulted in ~3-fold, or no deficiency. Three distinct LANA regions reorganized heterochromatin, one of which contains the deleted sequence, but the deletion did not abolish LANA's ability to alter chromatin. Therefore, this work identifies a short internal LANA sequence that is critical for DNA replication, has modest effects on episome segregation, and substantially impacts episome persistence; this region may exert its effects through an interacting host cell protein(s).
Collapse
Affiliation(s)
- Erika De León Vázquez
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, United States
| | | | | | | |
Collapse
|
39
|
Efficient replication of Epstein-Barr virus-derived plasmids requires tethering by EBNA1 to host chromosomes. J Virol 2013; 87:13020-8. [PMID: 24067969 DOI: 10.1128/jvi.01606-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The EBNA1 protein of Epstein-Barr virus enables plasmids carrying oriP both to duplicate and to segregate efficiently in proliferating cells. EBNA1 recruits the origin recognition complex (ORC) to establish a replication origin at one element of oriP, DS (dyad symmetry); at another element, FR (family of repeats), EBNA1 binds to an array of sites from which it tethers plasmids to host chromosomes for mitotic stability. We report experiments leading to the conclusion that tethering by EBNA1 to host chromosomes is also needed within interphase nuclei in order for plasmids to be replicated efficiently from oriP. The DNA-binding domain of EBNA1, which lacks chromosome-binding ability, was found to support weak, DS-specific replication in HEK293 cells after transient transfection, being 17% as active as wild-type EBNA1. The low efficiency of replication was not due to the failure of the DNA-binding domain to retain plasmids within nuclei, because plasmids were recovered in similar amounts and entirely from the nuclear fraction of these transiently transfected cells. A derivative of EBNA1 with its chromosome-tethering domains replaced by a 22-amino-acid nucleosome-binding domain was fully active in supporting oriP functions. The implication is that EBNA1's DNA-binding domain is able to recruit ORC to DS, but either this step or subsequent replication is only efficient if the plasmid is tethered to a host chromosome. Finally, with some cell lines, DS can hardly support even transient plasmid replication without FR. A loss of plasmids lacking FR from nuclei cannot account for this requirement, suggesting that the stronger tethering to chromosomes by FR is needed for plasmid replication within the nuclei of such cells.
Collapse
|
40
|
Identification of Kaposi's sarcoma-associated herpesvirus LANA regions important for episome segregation, replication, and persistence. J Virol 2013; 87:12270-83. [PMID: 24006437 DOI: 10.1128/jvi.01243-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) is a 1,162-amino-acid protein that mediates the maintenance of episomal viral genomes in latently infected cells. The two central components of episome persistence are DNA replication with each cell division and the segregation of DNA to progeny nuclei. LANA self-associates to bind KSHV terminal-repeat (TR) DNA and to mediate its replication. LANA also simultaneously binds to TR DNA and mitotic chromosomes to mediate the segregation of episomes to daughter nuclei. The N-terminal region of LANA binds histones H2A and H2B to attach to mitotic chromosomes, while the C-terminal region binds TR DNA and also associates with chromosomes. Both the N- and C-terminal regions of LANA are essential for episome persistence. We recently showed that deletion of all internal LANA sequences results in highly deficient episome maintenance. Here we assess independent internal LANA regions for effects on episome persistence. We generated a panel of LANA mutants that included deletions in the large internal repeat region and in the unique internal sequence. All mutants contained the essential N- and C-terminal regions, and as expected, all maintained the ability to associate with mitotic chromosomes in a wild-type fashion and to bind TR DNA, as assessed by electrophoretic mobility shift assays (EMSA). Deletion of the internal regions did not reduce the half-life of LANA. Notably, deletions within either the repeat elements or the unique sequence resulted in deficiencies in DNA replication. However, only the unique internal sequence exerted effects on the ability of LANA to retain green fluorescent protein (GFP) expression from TR-containing episomes deficient in DNA replication, consistent with a role in episome segregation; this region did not independently associate with mitotic chromosomes. All mutants were deficient in episome persistence, and the deficiencies ranged from minor to severe. Mutants deficient in DNA replication that contained deletions within the unique internal sequence had the most-severe deficits. These data suggest that internal LANA regions exert critical roles in LANA-mediated DNA replication, segregation, and episome persistence, likely through interactions with key host cell factors.
Collapse
|
41
|
Cha S, Seo T. Viral genome maintenance and latent replication of human gammaherpesviruses. Future Virol 2013. [DOI: 10.2217/fvl.13.37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
During gammaherpesvirus latency, only a few genes are expressed and required for maintenance of viral latency over a long period. While the expressed latent viral proteins play functional roles in viral latent DNA replication, they do not have replication-associated enzymatic activity such as polymerase or helicase activity. Viral genomes are detected in a similar copy number per infected cell, suggesting that the viral genome is replicated and segregated using host replication machinery. Kaposi’s sarcoma-associated herpesvirus and EBV have trans-acting elements required for viral genome maintenance during latency; LANA1 and EBNA1, respectively. The proteins recruit host replication-associated proteins at their latent origins, leading to initiation of viral replication and segregation with host chromosomes once per cell cycle. In addition, viral latent origins (cis-elements) provide trans-element-binding sites as well as a sufficient space for recruitment of cellular factors. In this review, we describe the molecular mechanisms required for replication of the viral genome during latency, including interactions with cellular factors and the interplay between viral trans- and cis-elements.
Collapse
Affiliation(s)
- Seho Cha
- Department of Life Science, Dongguk University-Seoul, 26, 3 Pil-dong, Jung-gu, Seoul, 100-715, Republic of Korea
| | - Taegun Seo
- Department of Life Science, Dongguk University-Seoul, 26, 3 Pil-dong, Jung-gu, Seoul, 100-715, Republic of Korea.
| |
Collapse
|
42
|
Xue M, Guo Y, Yan Q, Qin D, Lu C. Preparation and application of polyclonal antibodiesagainst KSHV v-cyclin. J Biomed Res 2013; 27:421-9. [PMID: 24086175 PMCID: PMC3783827 DOI: 10.7555/jbr.27.20120085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 11/20/2012] [Accepted: 12/04/2012] [Indexed: 12/12/2022] Open
Abstract
We prepared rabbit polyclonal antibodies against Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded v-cyclin (ORF 72) and detected the natural viral protein using these polyclonal antibodies. Three antigenic polypeptides of v-cyclin were designed and synthesized. A fragment of the v-cyclin gene was cloned into a eukaryotic expression vector pEF-MCS-Flag-IRES/Puro to construct a recombinant vector, pEF v-cyclin. Then, pEF v-cyclin was transfected into 293T and EA.hy926 cells to obtain v-cyclin-Flag fusion proteins. Six New Zealand white rabbits were immunized with KLH-conjugated peptides to generate polyclonal antibodies against v-cyclin. The polyclonal antibodies were then characterized by ELISA and Western blotting assays. Finally, the polyclonal antibodies against v-cyclin were used to detect natural viral protein expressed in BCBL-1, BC-3, and JSC-1 cells. The results showed that using the Flag antibody, v-cyclin-Flag fusion protein was detected in 293T and EA.hy926 cells transfected with pEF-v-cyclin. Furthermore, ELISA showed that the titer of the induced polyclonal rabbit anti-v-cyclin antibodies was higher than 1:8,000. In Western blotting assays, the antibodies reacted specifically with the v-cyclin-Flag fusion protein as well as the natural viral protein. The recombinant expression vector pEF-v-cyclin was constructed successfully, and the polyclonal antibodies prepared can be used for various biological tests including ELISA and Western blotting assays.
Collapse
Affiliation(s)
- Min Xue
- Department of Microbiology and Immunology, Nanjing Medical University, Nanjing 210029, P. R. China; ; Department of Physiology, Xuzhou Medical College, Xuzhou, Jiangsu, 221000, P. R. China; Jiangsu 223300, China
| | | | | | | | | |
Collapse
|
43
|
Kalashnikova AA, Porter-Goff ME, Muthurajan UM, Luger K, Hansen JC. The role of the nucleosome acidic patch in modulating higher order chromatin structure. J R Soc Interface 2013; 10:20121022. [PMID: 23446052 DOI: 10.1098/rsif.2012.1022] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Higher order folding of chromatin fibre is mediated by interactions of the histone H4 N-terminal tail domains with neighbouring nucleosomes. Mechanistically, the H4 tails of one nucleosome bind to the acidic patch region on the surface of adjacent nucleosomes, causing fibre compaction. The functionality of the chromatin fibre can be modified by proteins that interact with the nucleosome. The co-structures of five different proteins with the nucleosome (LANA, IL-33, RCC1, Sir3 and HMGN2) recently have been examined by experimental and computational studies. Interestingly, each of these proteins displays steric, ionic and hydrogen bond complementarity with the acidic patch, and therefore will compete with each other for binding to the nucleosome. We first review the molecular details of each interface, focusing on the key non-covalent interactions that stabilize the protein-acidic patch interactions. We then propose a model in which binding of proteins to the nucleosome disrupts interaction of the H4 tail domains with the acidic patch, preventing the intrinsic chromatin folding pathway and leading to assembly of alternative higher order chromatin structures with unique biological functions.
Collapse
Affiliation(s)
- Anna A Kalashnikova
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
| | | | | | | | | |
Collapse
|
44
|
Paden CR, Forrest JC, Tibbetts SA, Speck SH. Unbiased mutagenesis of MHV68 LANA reveals a DNA-binding domain required for LANA function in vitro and in vivo. PLoS Pathog 2012; 8:e1002906. [PMID: 22969427 PMCID: PMC3435236 DOI: 10.1371/journal.ppat.1002906] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 07/26/2012] [Indexed: 02/02/2023] Open
Abstract
The Latency-Associated Nuclear Antigen (LANA), encoded by ORF73, is a conserved gene among the γ2-herpesviruses (rhadinoviruses). The Kaposi's Sarcoma-Associated Herpesvirus (KSHV) LANA is consistently expressed in KSHV-associated malignancies. In the case of the rodent γ2-herpesvirus, murine gammaherpesvirus 68 (MHV68), the LANA homolog (mLANA) is required for efficient virus replication, reactivation from latency and immortalization of murine fetal liver-derived B cells. To gain insights into mLANA function(s), knowing that KSHV LANA binds DNA and can modulate transcription of a variety of promoters, we sought out and identified a mLANA-responsive promoter which maps to the terminal repeat (TR) of MHV68. Notably, mLANA strongly repressed activity from this promoter. We extended these analyses to demonstrate direct, sequence-specific binding of recombinant mLANA to TR DNA by DNase I footprinting. To assess whether the DNA-binding and/or transcription modulating function is important in the known mLANA phenotypes, we generated an unbiased library of mLANA point mutants using error-prone PCR, and screened a large panel of mutants for repression of the mLANA-responsive promoter to identify loss of function mutants. Notably, among the mutant mLANA proteins recovered, many of the mutations are in a predicted EBNA-1-like DNA-binding domain. Consistent with this prediction, those tested displayed loss of DNA binding activity. We engineered six of these mLANA mutants into the MHV68 genome and tested the resulting mutant viruses for: (i) replication fitness; (ii) efficiency of latency establishment; and (iii) reactivation from latency. Interestingly, each of these mLANA-mutant viruses exhibited phenotypes similar to the mLANA-null mutant virus, indicating that DNA-binding is critical for mLANA function. The human gammaherpesviruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are tightly associated with a number of different cancers. Unfortunately, due to their very narrow host tropism, characterizing the pathogenesis of these viruses has been difficult. Infection of laboratory mice with the rodent gammaherpesvirus, murine gammaherpesvirus 68 (MHV68), has proven to be an excellent approach for understanding how these viruses cause disease. One of the MHV68 encoded proteins, which is also found in KSHV, is called LANA and in the case of KSHV-associated diseases LANA expression is consistently detected in infected cells. Here we show that the MHV68 LANA shares a key function with the KSHV homolog—namely, modulating gene expression. Using a random mutagenesis protocol, we identified mLANA mutants that had lost transcriptional regulatory activity. We engineered these mutations back into the virus, used the viruses to infect mice, and find that this function is critical to LANA function in vivo and in vitro. This method, combined with the knowledge gained here, sets the stage for future studies to identify mutant forms of LANA that could be used to block wild type LANA function or, alternatively, to design drugs that target LANA function.
Collapse
Affiliation(s)
- Clinton R. Paden
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
- Immunology and Molecular Pathogenesis Graduate Program, Emory University, Atlanta, Georgia, United States of America
| | - J. Craig Forrest
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Scott A. Tibbetts
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, United States of America
| | - Samuel H. Speck
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, United States of America
- * E-mail:
| |
Collapse
|
45
|
Murine gammaherpesvirus 68 LANA acts on terminal repeat DNA to mediate episome persistence. J Virol 2012; 86:11863-76. [PMID: 22915819 DOI: 10.1128/jvi.01656-12] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Murine gammaherpesvirus 68 (MHV68) ORF73 (mLANA) has sequence homology to Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA). LANA acts on the KSHV terminal repeat (TR) elements to mediate KSHV episome maintenance. Disruption of mLANA expression severely reduces the ability of MHV68 to establish latent infection in mice, consistent with the possibility that mLANA mediates episome persistence. Here we assess the roles of mLANA and MHV68 TR (mTR) elements in episome persistence. mTR-associated DNA persisted as an episome in latently MHV68-infected tumor cells, demonstrating that the mTR elements can serve as a cis-acting element for MHV68 episome maintenance. In some cases, both control vector and mTR-associated DNAs integrated into MHV68 episomal genomes. Therefore, we also assessed the roles of mTRs as well as mLANA in the absence of infection. DNA containing both mLANA and mTRs in cis persisted as an episome in murine A20 or MEF cells. In contrast, mTR DNA never persisted as an episome in the absence of mLANA. mLANA levels were increased when mLANA was expressed from its native promoters, and episome maintenance was more efficient with higher mLANA levels. Increased numbers of mTRs conferred more efficient episome maintenance, since DNA containing mLANA and eight mTR elements persisted more efficiently in A20 cells than did DNA with mLANA and two or four mTRs. Similar to KSHV LANA, mLANA broadly associated with mitotic chromosomes but relocalized to concentrated dots in the presence of episomes. Therefore, mLANA acts on mTR elements to mediate MHV68 episome persistence.
Collapse
|
46
|
Kaposi's sarcoma-associated herpesvirus-encoded LANA recruits topoisomerase IIβ for latent DNA replication of the terminal repeats. J Virol 2012; 86:9983-94. [PMID: 22761383 DOI: 10.1128/jvi.00839-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The latency-associated nuclear antigen (LANA) encoded by Kaposi's sarcoma-associated herpesvirus (KSHV) plays a major role in maintaining latency and is critical for the perpetual segregation of viral episomes to the progeny nuclei of newly divided cells. LANA binds to KSHV terminal repeat (TR) DNA and tethers the viral episomes to host chromosomes through the association of chromatin-bound cellular proteins. TR elements serve as potential origin sites of KSHV replication and have been shown to play important roles in latent DNA replication and transcription of adjacent genes. Affinity chromatography and proteomics analysis using KSHV TR DNA and the LANA binding site as the affinity column identified topoisomerase IIβ (TopoIIβ) as a LANA-interacting protein. Here, we show that TopoIIβ forms complexes with LANA that colocalize as punctuate bodies in the nucleus of KSHV-infected cells. The specific TopoIIβ binding region of LANA has been identified to its N terminus and the first 32 amino acid residues containing the nucleosome-binding region crucial for binding. Moreover, this region could also act as a dominant negative to disrupt association of TopoIIβ with LANA. TopoIIβ plays an important role in LANA-dependent latent DNA replication, as addition of ellipticine, a selective inhibitor of TopoII, negatively regulated replication mediated by the TR. DNA break labeling and chromatin immunoprecipitation assay using biotin-16-dUTP and terminal deoxynucleotide transferase showed that TopoIIβ mediates a transient DNA break on viral DNA. These studies confirm that LANA recruits TopoIIβ at the origins of latent replication to unwind the DNA for replication.
Collapse
|
47
|
Ballestas ME, Kaye KM. The latency-associated nuclear antigen, a multifunctional protein central to Kaposi's sarcoma-associated herpesvirus latency. Future Microbiol 2012; 6:1399-413. [PMID: 22122438 DOI: 10.2217/fmb.11.137] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Latency-associated nuclear antigen (LANA) is encoded by the Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) open reading frame 73. LANA is expressed during latent KSHV infection of cells, including tumor cells, such as primary effusion lymphoma, KS and multicentric Castleman's disease. Latently infected cells have multiple extrachromosomal copies of covalently closed circular KSHV genomes (episomes) that are stably maintained in proliferating cells. LANA's best characterized function is that of mediating episome persistence. It does so by binding terminal repeat sequences to the chromosomal matrix, thus ensuring episome replication with each cell division and efficient DNA segregation to daughter nuclei after mitosis. To achieve these functions, LANA associates with different host cell proteins, including chromatin-associated proteins and proteins involved in DNA replication. In addition to episome maintenance, LANA has transcriptional regulatory effects and affects cell growth. LANA exerts these functions through interactions with different cell proteins.
Collapse
Affiliation(s)
- Mary E Ballestas
- Department of Pediatrics, Division of Infectious Diseases, University of Alabama in Birmingham, School of Medicine, Children's Harbor Building, Room 148, 1600 6th Ave South, Birmingham, AL 35233, USA
| | | |
Collapse
|
48
|
The internal Kaposi's sarcoma-associated herpesvirus LANA regions exert a critical role on episome persistence. J Virol 2011; 85:7622-33. [PMID: 21593163 DOI: 10.1128/jvi.00304-11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) is a 1,162-amino-acid protein that acts on viral terminal repeat (TR) DNA to mediate KSHV episome persistence. The two essential components of episome persistence are DNA replication prior to cell division and episome segregation to daughter nuclei. These functions are located within N- and C-terminal regions of LANA. N- and C-terminal regions of LANA are sufficient for TR DNA replication. In addition, N- and C-terminal regions of LANA tether episomes to mitotic chromosomes to segregate episomes to progeny cell nuclei. To generate a tethering mechanism, N-terminal LANA binds histones H2A/H2B to attach to mitotic chromosomes, and C-terminal LANA binds TR DNA and also associates with mitotic chromosomes. Here, we test the importance of the internal LANA sequence for episome persistence. We generated LANA mutants that contain N- and C-terminal regions of LANA but have most of the internal sequence deleted. As expected, the LANA mutants bound mitotic chromosomes in a wild-type pattern and also bound TR DNA as assayed by electrophoretic mobility shift assays (EMSA). The mutants mediated TR DNA replication, although with reduced efficiency compared with LANA. Despite the ability to replicate DNA and exert the chromosome and DNA binding functions necessary for segregating episomes to daughter nuclei, the mutants were highly deficient for the ability to mediate both short- and long-term episome persistence. These data indicate that internal LANA sequence exerts a critical effect on its ability to maintain episomes, possibly through effects on TR DNA replication.
Collapse
|
49
|
Cherezova L, Burnside KL, Rose TM. Conservation of complex nuclear localization signals utilizing classical and non-classical nuclear import pathways in LANA homologs of KSHV and RFHV. PLoS One 2011; 6:e18920. [PMID: 21559489 PMCID: PMC3084728 DOI: 10.1371/journal.pone.0018920] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 03/23/2011] [Indexed: 11/18/2022] Open
Abstract
ORF73 latency-associated nuclear antigen (LANA) of the Kaposi's sarcoma-associated herpesvirus (KSHV) is targeted to the nucleus of infected cells where it binds to chromatin and mediates viral episome persistence, interacts with cellular proteins and plays a role in latency and tumorigenesis. A structurally related LANA homolog has been identified in the retroperitoneal fibromatosis herpesvirus (RFHV), the macaque homolog of KSHV. Here, we report the evolutionary and functional conservation of a novel bi-functional nuclear localization signal (NLS) in KSHV and RFHV LANA. N-terminal peptides from both proteins were fused to EGFP or double EGFP fusions to examine their ability to induce nuclear transport of a heterologous protein. In addition, GST-pull down experiments were used to analyze the ability of LANA peptides to interact with members of the karyopherin family of nuclear transport receptors. Our studies revealed that both LANA proteins contain an N-terminal arginine/glycine (RG)-rich domain spanning a conserved chromatin-binding motif, which binds directly to importin β1 in a RanGTP-sensitive manner and serves as an NLS in the importin β1-mediated non-classical nuclear import pathway. Embedded within this domain is a conserved lysine/arginine-(KR)-rich bipartite motif that binds directly to multiple members of the importin α family of nuclear import adaptors in a RanGTP-insensitive manner and serves as an NLS in the classical importin α/β-mediated nuclear import pathway. The positioning of a classical bipartite kr-NLS embedded within a non-classical rg-NLS is a unique arrangement in these viral proteins, whose nuclear localization is critical to their functionality and to the virus life cycle. The ability to interact with multiple import receptors provides alternate pathways for nuclear localization of LANA. Since different import receptors can import cargo to distinct subnuclear compartments, a multifunctional NLS may provide LANA with an increased ability to interact with different nuclear components in its multifunctional role to maintain viral latency.
Collapse
Affiliation(s)
- Lidia Cherezova
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Center for Childhood Infections and Prematurity Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
| | - Kellie L. Burnside
- Center for Childhood Infections and Prematurity Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
- Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
| | - Timothy M. Rose
- Center for Childhood Infections and Prematurity Research, Seattle Children's Research Institute, Seattle, Washington, United States of America
- Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| |
Collapse
|
50
|
De León Vázquez E, Kaye KM. Rapid and quantitative assessment of KSHV LANA-mediated DNA replication. Arch Virol 2011; 156:1323-33. [PMID: 21472413 DOI: 10.1007/s00705-011-0985-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 03/17/2011] [Indexed: 11/27/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) latency-associated nuclear antigen (LANA) mediates DNA replication of terminal repeat (TR) DNA to enable viral episome persistence in latently infected cells. Southern blotting is routinely used to detect LANA-replicated DNA. We developed and validated a real-time PCR assay for TR-associated DNA and compared it with Southern blot analysis. Both PCR and Southern blot detected LANA-replicated DNA, but the PCR assay was more rapid and did not require radioisotope. PCR detection at 24 and 72 hours post-transfection demonstrated rapid loss of transfected TR DNA. LANA, and to a lesser extent a moderately deficient LANA mutant, reduced the rate of DNA loss through addition of replicated TR DNA and reduction in the loss of non-replicated DNA, the latter of which is consistent with LANA's nuclear segregation function. Therefore, this work develops a rapid, sensitive, and quantitative PCR (qPCR) assay to detect KSHV LANA-replicated DNA and demonstrates that LANA reduces TR DNA loss after transfection through replication and nuclear partitioning of TR DNA.
Collapse
Affiliation(s)
- Erika De León Vázquez
- Channing Laboratory and Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, USA
| | | |
Collapse
|