scholarly journals Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen: Replicating and Shielding Viral DNA during Viral Persistence

2017 ◽  
Vol 91 (14) ◽  
Author(s):  
Magdalena Weidner-Glunde ◽  
Giuseppe Mariggiò ◽  
Thomas F. Schulz
Keyword(s):  
Dna Replication ◽  
Viral Genome ◽  
Kaposi's Sarcoma ◽  
Viral Latency ◽  
Viral Persistence ◽  
Kaposi’S Sarcoma ◽  
Nuclear Antigen ◽  
Current View ◽  
Dna Binding Domain ◽  
Viral Dna

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.

scholarly journals Accumulation of Heterochromatin Components on the Terminal Repeat Sequence of Kaposi's Sarcoma-Associated Herpesvirus Mediated by the Latency-Associated Nuclear Antigen

2004 ◽  
Vol 78 (14) ◽  
pp. 7299-7310 ◽  
Author(s):  
Shuhei Sakakibara ◽  
Keiji Ueda ◽  
Ken Nishimura ◽  
Eunju Do ◽  
Eriko Ohsaki ◽  
...  
Keyword(s):  
Viral Genome ◽  
Kaposi's Sarcoma ◽  
Specific Binding ◽  
Viral Latency ◽  
Kaposi’S Sarcoma ◽  
Repeat Sequence ◽  
Terminal Repeat ◽  
Nuclear Antigen ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT In the latent infection of Kaposi's sarcoma-associated herpesvirus (KSHV), its 160-kb circularized episomal DNA is replicated and maintained in the host nucleus. KSHV latency-associated nuclear antigen (LANA) is a key factor for maintaining viral latency. LANA binds to the terminal repeat (TR) DNA of the viral genome, leading to its localization to specific dot structures in the nucleus. In such an infected cell, the expression of the viral genes is restricted by a mechanism that is still unclear. Here, we found that LANA interacts with SUV39H1 histone methyltransferase, a key component of heterochromatin formation, as determined by use of a DNA pull-down assay with a biotinylated DNA fragment that contained a LANA-specific binding sequence and a maltose-binding protein pull-down assay. The diffuse localization of LANA on the chromosomes of uninfected cells changed to a punctate one with the introduction of a bacterial artificial chromosome containing most of the TR region, and SUV39H1 clearly colocalized with the LANA-associated dots. Thus, the LANA foci in KSHV-infected cells seemed to include SUV39H1 as well as heterochromatin protein 1. Furthermore, a chromatin immunoprecipitation assay revealed that the TR and the open reading frame (ORF) K1 and ORF50/RTA genes, but not the ORF73/LANA gene, lay within the heterochromatin during KSHV latency. Taken together, these observations indicate that LANA recruits heterochromatin components to the viral genome, which may lead to the establishment of viral latency and govern the transcription program.

scholarly journals Mitotic Chromosome-Binding Activity of Latency-Associated Nuclear Antigen 1 Is Required for DNA Replication from Terminal Repeat Sequence of Kaposi's Sarcoma-Associated Herpesvirus

2004 ◽  
Vol 78 (13) ◽  
pp. 7248-7256 ◽  
Author(s):  
Chunghun Lim ◽  
Changtaek Choi ◽  
Joonho Choe
Keyword(s):  
Dna Replication ◽  
Viral Genome ◽  
Kaposi's Sarcoma ◽  
Mitotic Chromosome ◽  
Kaposi’S Sarcoma ◽  
Binding Activity ◽  
Terminal Repeat ◽  
Nuclear Antigen ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
Chromosome Binding

ABSTRACT Latency-associated nuclear antigen 1 (LANA1) of Kaposi's sarcoma-associated herpesvirus (KSHV) is implicated in the persistence of the viral genome during latent infection. It has been suggested that LANA1 tethers the viral genome to the host chromosome and also participates actively in DNA replication from the terminal repeat of KSHV. Here we show by mutational analysis that the mitotic chromosome-binding activity of LANA1 is tightly coupled to its replication activity. Thus, KSHV appears to have evolved a unique tactic for its stable maintenance.

scholarly journals Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen Induces a Strong Bend on Binding to Terminal Repeat DNA

2005 ◽  
Vol 79 (21) ◽  
pp. 13829-13836 ◽  
Author(s):  
Lai-Yee Wong ◽  
Angus C. Wilson
Keyword(s):  
Dna Replication ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Nuclear Antigen ◽  
Major Groove ◽  
Repeat Dna ◽  
Initiation Of Dna Replication ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
Herpesvirus Genome

ABSTRACT During latency, the Kaposi's sarcoma-associated herpesvirus genome is maintained as a circular episome, replicating in synchrony with host chromosomes. Replication requires the latency-associated nuclear antigen (LANA) and an origin of latent DNA replication located in the viral terminal repeats, consisting of two LANA binding sites (LBSs) and a GC-rich sequence. Here, we show that the recruitment of a LANA dimer to high-affinity site LBS-1 bends DNA by 57° and towards the major groove. The cooccupancy of LBS-1 and lower-affinity LBS-2 induces a symmetrical bend of 110°. By changing the origin architecture, LANA may help to assemble a specific nucleoprotein structure important for the initiation of DNA replication.

scholarly journals Bub1 in Complex with LANA Recruits PCNA To Regulate Kaposi's Sarcoma-Associated Herpesvirus Latent Replication and DNA Translesion Synthesis

2015 ◽  
Vol 89 (20) ◽  
pp. 10206-10218 ◽  
Author(s):  
Zhiguo Sun ◽  
Hem Chandra Jha ◽  
Erle S. Robertson
Keyword(s):  
Dna Replication ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Kinase Domain ◽  
Cellular Protein ◽  
Nuclear Antigen ◽  
Infected Cells ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
Molecular Bridge

ABSTRACTLatent DNA replication of Kaposi's sarcoma-associated herpesvirus (KSHV) initiates at the terminal repeat (TR) element and requirestrans-acting elements, both viral and cellular, such as ORCs, MCMs, and latency-associated nuclear antigen (LANA). However, how cellular proteins are recruited to the viral genome is not very clear. Here, we demonstrated that the host cellular protein, Bub1, is involved in KSHV latent DNA replication. We show that Bub1 constitutively interacts with proliferating cell nuclear antigen (PCNA) via a highly conserved PIP box motif within the kinase domain. Furthermore, we demonstrated that Bub1 can form a complex with LANA and PCNA in KSHV-positive cells. This strongly indicated that Bub1 serves as a scaffold or molecular bridge between LANA and PCNA. LANA recruited PCNA to the KSHV genome via Bub1 to initiate viral replication in S phase and interacted with PCNA to promote its monoubiquitination in response to UV-induced damage for translesion DNA synthesis. This resulted in increased survival of KSHV-infected cells.IMPORTANCEDuring latency in KSHV-infected cells, the viral episomal DNA replicates once each cell cycle. KSHV does not express DNA replication proteins during latency. Instead, KSHV LANA recruits the host cell DNA replication machinery to the replication origin. However, the mechanism by which LANA mediates replication is uncertain. Here, we show that LANA is able to form a complex with PCNA, a critical protein for viral DNA replication. Furthermore, our findings suggest that Bub1, a spindle checkpoint protein, serves as a scaffold or molecular bridge between LANA and PCNA. Our data further support a role for Bub1 and LANA in PCNA-mediated cellular DNA replication processes as well as monoubiquitination of PCNA in response to UV damage. These data reveal a therapeutic target for inhibition of KSHV persistence in malignant cells.

scholarly journals Identification of a virus trans-acting regulatory element on the latent DNA replication of Kaposi's sarcoma-associated herpesvirus

2004 ◽  
Vol 85 (4) ◽  
pp. 843-855 ◽  
Author(s):  
Chunghun Lim ◽  
Taegun Seo ◽  
Jun Jung ◽  
Joonho Choe
Keyword(s):  
Dna Replication ◽  
Cell Lines ◽  
Kaposi's Sarcoma ◽  
Regulatory Element ◽  
Kaposi’S Sarcoma ◽  
Virus Genome ◽  
Nuclear Antigen ◽  
N Terminus ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

Latency-associated nuclear antigen 1 (LANA1) of Kaposi's sarcoma-associated herpesvirus (KSHV) plays a pivotal role in the maintenance of the virus genome in latently infected cells. LANA1 links virus genomes to host chromosomes via a C-terminal DNA-binding domain which interacts with the sequences located in terminal repeats (TRs) of the virus genome and via an N-terminal chromosome-binding sequence which associates with the host chromosomes, respectively. Recent data suggest that LANA1 also actively participates in the replication of KSHV TR-containing plasmid in the transient DNA replication assay. In this report, it was found that C33A and COS-1, but not NIH/3T3, cell lines are permissive for the transient replication of KSHV TR-containing plasmid. Using several LANA1-deletion mutants, the minimum domain of LANA1 required for replication activity was also determined. In addition, the N terminus of LANA1 inhibited the transient replication systems of KSHV and Epstein–Barr virus (EBV) in transiently transfected 293 and 293T cells, but the C terminus of LANA1 specifically inhibited the transient replication system of KSHV in other cell lines. Consistent with previous reports, these data further emphasize the functional importance of the N terminus of LANA1 on replication from the KSHV latent origin of DNA replication.

scholarly journals The Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen 1 N Terminus Is Essential for Chromosome Association, DNA Replication, and Episome Persistence

2004 ◽  
Vol 78 (1) ◽  
pp. 294-301 ◽  
Author(s):  
Andrew J. Barbera ◽  
Mary E. Ballestas ◽  
Kenneth M. Kaye
Keyword(s):  
Dna Replication ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Chromosome Association ◽  
Nuclear Antigen ◽  
Mitotic Chromosomes ◽  
Proliferating Cells ◽  
N Terminus ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT To persist in latently infected, proliferating cells, Kaposi's sarcoma-associated herpesvirus (KSHV) episomes must replicate and efficiently segregate to progeny nuclei. Episome persistence in uninfected cells requires latency-associated nuclear antigen 1 (LANA1) in trans and cis-acting KSHV terminal repeat (TR) DNA. The LANA1 C terminus binds TR DNA, and LANA1 mediates TR-associated DNA replication in transient assays. LANA1 also concentrates at sites of KSHV TR DNA episomes along mitotic chromosomes, consistent with a tethering role to efficiently segregate episomes to progeny nuclei. LANA1 amino acids 5 to 22 constitute a chromosome association region (Piolot et al., J. Virol. 75:3948-3959, 2001). We now investigate LANA1 residues 5 to 22 with scanning alanine substitutions. Mutations targeting LANA1 5GMR7, 8LRS10, and 11GRS13 eliminated chromosome association, DNA replication, and episome persistence. LANA1 mutated at 14TG15 retained the ability to associate with chromosomes but was partially deficient in DNA replication and episome persistence. These results provide genetic support for a key role of the LANA1 N terminus in chromosome association, LANA1-mediated DNA replication, and episome persistence.

scholarly journals Latency-Associated Nuclear Antigen of Kaposi's Sarcoma-Associated Herpesvirus Recruits Uracil DNA Glycosylase 2 at the Terminal Repeats and Is Important for Latent Persistence of the Virus

2006 ◽  
Vol 80 (22) ◽  
pp. 11178-11190 ◽  
Author(s):  
Subhash C. Verma ◽  
Bharat G. Bajaj ◽  
Qiliang Cai ◽  
Huaxin Si ◽  
Todd Seelhammer ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Cell Line ◽  
Viral Genome ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Dna Glycosylase ◽  
Nuclear Antigen ◽  
Affinity Column ◽  
Uracil Dna Glycosylase ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT Latency-associated nuclear antigen (LANA) of KSHV is expressed in all forms of Kaposi's sarcoma-associated herpesvirus (KSHV)-mediated tumors and is important for TR-mediated replication and persistence of the virus. LANA does not exhibit any enzymatic activity by itself but is critical for replication and maintenance of the viral genome. To identify LANA binding proteins, we used a LANA binding sequence 1 DNA affinity column and determined the identities of a number of proteins associated with LANA. One of the identified proteins was uracil DNA glycosylase 2 (UNG2). UNG2 is important for removing uracil residues yielded after either misincorporation of dUTP during replication or deamination of cytosine. The specificity of the ′LANA-UNG2 interaction was confirmed by using a scrambled DNA sequence affinity column. Interaction of LANA and UNG2 was further confirmed by in vitro binding and coimmunoprecipitation assays. Colocalization of these proteins was also detected in primary effusion lymphoma (PEL) cells, as well as in a cotransfected KSHV-negative cell line. UNG2 binds to the carboxyl terminus of LANA and retains its enzymatic activity in the complex. However, no major effect on TR-mediated DNA replication was observed when a UNG2-deficient (UNG−/−) cell line was used. Infection of UNG−/− and wild-type mouse embryonic fibroblasts with KSHV did not reveal any difference; however, UNG−/− cells produced a significantly reduced number of virion particles after induction. Interestingly, depletion of UNG2 in PEL cells with short hairpin RNA reduced the number of viral genome copies and produced infection-deficient virus.

scholarly journals Involvement of SSRP1 in Latent Replication of Kaposi's Sarcoma-Associated Herpesvirus

2009 ◽  
Vol 83 (21) ◽  
pp. 11051-11063 ◽  
Author(s):  
Jianhong Hu ◽  
Eugene Liu ◽  
Rolf Renne
Keyword(s):  
Dna Replication ◽  
Kaposi's Sarcoma ◽  
Latent Infection ◽  
Mutational Analysis ◽  
Human Herpesvirus ◽  
Kaposi’S Sarcoma ◽  
Dominant Negative ◽  
Nuclear Antigen ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT Kaposi's sarcoma-associated herpesvirus (also named human herpesvirus 8) is a γ-herpesvirus that undergoes both lytic and latent infection. During latent infection, two viral elements are required: latency-associated nuclear antigen (LANA), which functions as an origin binding protein, and the latent origin, which resides within the terminal repeats (TRs) of the viral genome. Previously, we identified two cis-elements within the TRs which are required for latent DNA replication: two LANA binding sites (LBS1 and LBS2 [LBS1/2]) and a GC-rich replication element (RE) upstream of LBS1/2. To further characterize the RE, we constructed a 71-bp minimal replicon (MR) and performed a detailed mutational analysis. Our data indicate that the first 8 nucleotides within the RE are critical for replication. Moreover, both the position and the distance between the RE and LBS1/2 can affect origin replication activity, suggesting that the RE may function as a loading pad for cellular proteins involved in replication. Using biotinylated DNA fragments of wild-type or mutant MRs as probes, we identified 30 proteins that preferentially bind to the origin. Among these proteins, structure-specific recognition protein 1 (SSRP1), a subunit of the FACT complex, and telomeric repeat binding factor 2 (TRF2) formed complexes with LANA at the MR region. Furthermore, the small interfering RNA-based knockdown of SSRP1, but not the dominant-negative-based knockdown of TRF2, significantly decreased the efficiency of LANA-dependent DNA replication. These results indicate that SSRP1 is a novel cellular protein involved in LANA-dependent DNA replication.

scholarly journals Kaposi's Sarcoma-Associated Herpesvirus-Encoded Protein Kinase and Its Interaction with K-bZIP

2006 ◽  
Vol 81 (3) ◽  
pp. 1072-1082 ◽  
Author(s):  
Yoshihiro Izumiya ◽  
Chie Izumiya ◽  
Albert Van Geelen ◽  
Don-Hong Wang ◽  
Kit S. Lam ◽  
...  
Keyword(s):  
Dna Replication ◽  
Protein Kinase ◽  
Viral Protein ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Viral Transcription ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Kaposi’S Sarcoma Associated Herpesvirus

ABSTRACT The oncogenic herpesvirus, Kaposi's sarcoma-associated herpesvirus, also identified as human herpesvirus 8, contains genes producing proteins that control transcription and influence cell signaling. Open reading frame 36 (ORF36) of this virus encodes a serine/threonine protein kinase, which is designated the viral protein kinase (vPK). Our recent efforts to elucidate the role of vPK in the viral life cycle have focused on identifying viral protein substrates and determining the effects of vPK-mediated phosphorylation on specific steps in viral replication. The vPK gene was transcribed into 4.2-kb and 3.6-kb mRNAs during the early and late phases of viral reactivation. vPK is colocalized with viral DNA replication/transcription compartments as marked by a polymerase processivity factor, and K-bZIP, a protein known to bind the viral DNA replication origin (Ori-Lyt) and to regulate viral transcription. The vPK physically associated with and strongly phosphorylated K-bZIP at threonine 111, a site also recognized by the cyclin-dependent kinase Cdk2. Both K-bZIP and vPK were corecruited to viral promoters targeted by K-bZIP as well as to the Ori-Lyt region. Phosphorylation of K-bZIP by vPK had a negative impact on K-bZIP transcription repression activity. The extent of posttranslational modification of K-bZIP by sumoylation, a process that influences its repression function, was decreased by vPK phosphorylation at threonine 111. Our data thus identify a new role of vPK as a modulator of viral transcription.

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