H2AX Phosphorylation Is Important for LANA-Mediated Kaposi's Sarcoma-Associated Herpesvirus Episome Persistence

Jha, Hem Chandra; Upadhyay, Santosh Kumar; Aj, Mahadesh Prasad; Lu, Jie; Cai, Qiliang; Saha, Abhik; Robertson, Erle S.

doi:10.1128/jvi.03575-12

Cited by 58 publications

(90 citation statements)

References 62 publications

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“…KSHV latent proteins have been shown to induce H2AX phosphorylation (21,22), and phosphorylation of H2AX has been observed in KSHV-positive KS lesions (21). Corroborating those reports, our present results demonstrate that the KSHV-induced phosphorylation of H2AX observed during the late stages of de novo infection in primary endothelial cells is dependent on viral gene expression, as UV-inactivated KSHV could not induce such a response at late time points of infection.…”

Section: Discussionsupporting

confidence: 75%

“…Ectopic expression of KSHV latent viral Cyclin (vCyclin) protein in telomere-immortalized human endothelial cells leads to DDR activation, as evidenced by the phosphorylation of ATM, H2AX, CHK2, and p53 and S-phase arrest (21). Additionally, KSHV-encoded latency-associated nuclear antigen 1 (LANA-1) had a role in H2AX phosphorylation, and H2AX colocalized with the complex between LANA-1 and the terminal repeats (TRs) of the KSHV episome, an essential step in tethering of viral DNA to the host chromosome (22). In contrast, KSHV interferon regulatory factor 1 (IRF1), an immediate early (IE) lytic protein, inhibited ATM signaling during reactivation by direct interaction with ATM kinase (23).…”

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confidence: 99%

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Kaposi's Sarcoma-Associated Herpesvirus Induces the ATM and H2AX DNA Damage Response Early during De Novo Infection of Primary Endothelial Cells, Which Play Roles in Latency Establishment

Singh

Dutta

Ansari

et al. 2014

J Virol

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The DNA damage response (DDR) that evolved to repair host cell DNA damage also recognizes viral DNA entering the nucleus during infections. Here, we investigated the modulation of DDR signaling during de novo infection of primary endothelial cells by Kaposi's sarcoma-associated herpesvirus (KSHV). Phosphorylation of representative DDR-associated proteins, such as ataxia telangiectasia mutated (ATM) and H2AX, was induced as early as 30 min (0.5 h) postinfection and persisted during in vitro KSHV latency. Phosphorylated H2AX (␥H2AX) colocalized at 30 min (0.5 h) with the KSHV genome entering the nuclei. Total H2AX protein levels also increased, and the increase was attributed to a decrease in degradative H2AX Lys48-linked polyubiquitination with a concomitant increase in Lys63-linked polyubiquitination that was shown to increase protein stability. ATM and H2AX phosphorylation and ␥H2AX nuclear foci were also induced by UV-inactivated KSHV, which ceased at later times of infection. Inhibition of ATM kinase activity by KU-55933 and H2AX knockdown by small interfering RNA significantly reduced the expression of the KSHV latency-associated nuclear antigen 1 (LANA-1; ORF73) and LANA-1 nuclear puncta. Knockdown of H2AX also resulted in a >80% reduction in the nuclear KSHV DNA copy numbers. Similar results were also observed in ATMnegative cells, although comparable levels of viral DNA entered ATM-negative and ATM-positive cell nuclei. In contrast, knockdown of CHK1 and CHK2 did not affect ORF73 expression. Collectively, these results demonstrate that KSHV induces ATM and H2AX, a selective arm of the DDR, for the establishment and maintenance of its latency during de novo infection of primary endothelial cells. IMPORTANCEEukaryotic cells mount a DNA damage response (DDR) to sense and repair different types of cellular DNA damage. In addition, DDR also recognizes exogenous genetic material, such as the viral DNA genome entering the nucleus during infections. The present study was undertaken to determine whether de novo Kaposi's sarcoma-associated herpesvirus (KSHV) infection modulates DDR. Our results demonstrate that early during de novo infection of primary endothelial cells, KSHV induces a selective arm of DDR signaling, such as the ATM kinase and its downstream target, H2AX, which are essential for KSHV's latent gene expression and the establishment of latency. These studies suggest that targeting ATM and H2AX could serve as an attractive strategy to block the establishment of KSHV latent infection and the associated malignancies.

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Section: Discussionsupporting

confidence: 75%

mentioning

confidence: 99%

Kaposi's Sarcoma-Associated Herpesvirus Induces the ATM and H2AX DNA Damage Response Early during De Novo Infection of Primary Endothelial Cells, Which Play Roles in Latency Establishment

Singh

Dutta

Ansari

et al. 2014

J Virol

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“…Additionally, the lytic products of mu- rid herpesvirus 68 (MHV68) (Orf36 kinase) and its EBV homolog (BGLF4) induce ␥H2AX, and this modification is critical for efficient MHV68 replication and also may be required for EBV (54). The phosphorylation of H2AX also contributes to LANA-mediated episomal maintenance and may be important in the establishment of Kaposi's sarcoma-associated herpesvirus (KSHV) latency (25). Although activation of DDR signaling is required for replication of many DNA viruses, DDR signaling can result in deleterious effects, including triggering of apoptosis and cell cycle arrest.…”

Section: Discussionmentioning

confidence: 99%

“…EBV, as well as other oncogenic viruses, can modulate members of the DDR pathway, specifically the histone variant H2AX, to promote oncogenesis. Phosphorylation of H2AX can be critical for the maintenance of latent gammaherpesvirus infections (25,26). In contrast, EBV-mediated B cell immortalization requires the attenuation of DDR by EBNA3C, which may be mediated by downregulation of H2AX expression (27,28).…”

Section: Importancementioning

confidence: 99%

Regulation of DNA Damage Signaling and Cell Death Responses by Epstein-Barr Virus Latent Membrane Protein 1 (LMP1) and LMP2A in Nasopharyngeal Carcinoma Cells

Wasil

Wei

Chang

et al. 2015

J Virol

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Nasopharyngeal carcinoma (NPC) is closely associated with latent Epstein-Barr virus (EBV) infection. Although EBV infection of preneoplastic epithelial cells is not immortalizing, EBVcan modulate oncogenic and cell death mechanisms. The viral latent membrane proteins 1 (LMP1) and LMP2A are consistently expressed in NPC and can cooperate in bitransgenic mice expressed from the keratin-14 promoter to enhance carcinoma development in an epithelial chemical carcinogenesis model. In this study, LMP1 and LMP2A were coexpressed in the EBV-negative NPC cell line HK1 and examined for combined effects in response to genotoxic treatments. In response to DNA damage activation, LMP1 and LMP2A coexpression reduced ␥H2AX (S139) phosphorylation and caspase cleavage induced by a lower dose (5 M) of the topoisomerase II inhibitor etoposide. Regulation of ␥H2AX occurred before the onset of caspase activation without modulation of other DNA damage signaling mediators, including ATM, Chk1, or Chk2, and additionally was suppressed by inducers of DNA single-strand breaks (SSBs) and replication stress. Despite reduced DNA damage repair signaling, LMP1-2A coexpressing cells recovered from cytotoxic doses of etoposide; however, LMP1 expression was sufficient for this effect. LMP1 and LMP2A coexpression did not enhance cell growth, with a moderate increase of cell motility to fibronectin. This study supports that LMP1 and LMP2A jointly regulate DNA repair signaling and cell death activation with no further enhancement in the growth properties of neoplastic cells. E pstein-Barr virus (EBV) is a human gammaherpesvirus that establishes lifelong latency in memory B cells, with sporadic reactivation and transmission from oral epithelia (1). More than 90% of the adult population is latently infected, and a subset can develop EBV-associated malignancies, including nasopharyngeal carcinoma (NPC), gastric cancer, Burkitt lymphoma, Hodgkin lymphoma, and lymphomas in the immunocompromised, including AIDS-associated lymphoma and posttransplant lymphoproliferative disease (2, 3). Epithelial cell infection in vitro frequently results in productive replication, and latently infected oral epithelial cells are rare in persistently infected healthy individuals (4, 5). However, epithelial tumors such as NPC consistently express a type II latency program, which includes latent membrane protein 1 (LMP1), LMP2A, and LMP2B (1, 5). Additionally, monoclonal EBV episomes are detected in NPC, suggesting that NPC tumors are the clonal outgrowth of an initially infected cell likely predisposed to oncogenic transformation from additional genetic and environmental cofactors, such as the loss of p16 and exposure to dietary nitrosamines (2, 3). In contrast to the immortalizing properties of EBV to primary B cells, the contribution of EBV infection to epithelial cell oncogenesis is less understood, as infection alone is insufficient to immortalize or induce oncogenic potential in preneoplastic cell lines from the nasopharynx (5, 6).LMP1 and LMP2A transcripts are ...

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“…During de novo infection of primary endothelial cells, KSHV activates phosphorylation of ATM and H2AX for establishing viral latency . Further studies indicate that KSHV encoded LANA interacts with H2AX and induces phosphorylation of γH2AX at serine 139 for episome persistence (Jha et al, 2013). Similarly, EBV also modulates the activation of DDR signaling during its lytic cycle, through Ztamediated phosphorylation of ATM and γH2AX (Wang' ondu et al, 2015).…”

Section: Phosphorylation-mediated Viral Manipulation Of Dna Damage Rementioning

confidence: 99%

The regulatory role of protein phosphorylation in human gammaherpesvirus associated cancers

et al. 2017

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Activation of specific sets of protein kinases by intracellular signal molecules has become more and more apparent in the past decade. Phosphorylation, one of key posttranslational modification events, is activated by kinase or regulatory protein and is vital for controlling many physiological functions of eukaryotic cells such as cell proliferation, differentiation, malignant transformation, and signal transduction mediated by external stimuli. Moreovers, the reversible modification of phosphorylation and dephosphorylation can result in different features of the target substrate molecules including DNA binding, protein-protein interaction, subcellular location and enzymatic activity, and is often hijacked by viral infection. Epstein-Barr virus (EBV) and Kaposi's sarcomaassociated herpesvirus (KSHV), two human oncogenic gamma-herpesviruses, are shown to tightly associate with many malignancies. In this review, we summarize the recent progresses on understanding of molecular properties and regulatory modes of cellular and viral proteins phosphorylation influenced by these two tumor viruses, and highlight the potential therapeutic targets and strategies against their related cancers.

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H2AX Phosphorylation Is Important for LANA-Mediated Kaposi's Sarcoma-Associated Herpesvirus Episome Persistence

Cited by 58 publications

References 62 publications

Kaposi's Sarcoma-Associated Herpesvirus Induces the ATM and H2AX DNA Damage Response Early during De Novo Infection of Primary Endothelial Cells, Which Play Roles in Latency Establishment

Kaposi's Sarcoma-Associated Herpesvirus Induces the ATM and H2AX DNA Damage Response Early during De Novo Infection of Primary Endothelial Cells, Which Play Roles in Latency Establishment

Regulation of DNA Damage Signaling and Cell Death Responses by Epstein-Barr Virus Latent Membrane Protein 1 (LMP1) and LMP2A in Nasopharyngeal Carcinoma Cells

The regulatory role of protein phosphorylation in human gammaherpesvirus associated cancers

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