γ-Herpesvirus Kinase Actively Initiates a DNA Damage Response by Inducing Phosphorylation of H2AX to Foster Viral Replication

Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Cell host & microbe (Impact Factor: 12.33). 07/2007; 1(4):275-86. DOI: 10.1016/j.chom.2007.05.008
Source: PubMed


DNA virus infection can elicit the DNA damage response in host cells, including ATM kinase activation and H2AX phosphorylation. This is considered to be the host cell response to replicating viral DNA. In contrast, we show that during infection of macrophages murine gamma-herpesvirus 68 (gammaHV68) actively induces H2AX phosphorylation by expressing a viral kinase (orf36). GammaHV68-encoded orf36 kinase and its EBV homolog, BGLF4, induce H2AX phosphorylation independently of other viral genes. The process requires the kinase domain of Orf36 and is enhanced by ATM. Orf36 is important for gammaHV68 replication in infected animals, and orf36, H2AX, and ATM are all critical for efficient gammaHV68 replication in primary macrophages. Thus, activation of proximal components of the DNA damage signaling response is an active viral kinase-driven strategy required for efficient gamma-herpesvirus replication.

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Available from: Vera L Tarakanova, Oct 04, 2015
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    • "HSV infection of ATM-deficient cells failed to induce phosphorylation of a member of the MRN complex (Nbs1), Chk2, and p53 indicating that the DNA damage response requires activation of ATM in HSV infected cells (Lilley et al., 2005; Shirata et al., 2005). Interestingly, while ATM is not needed for replication of MHV68 in mouse fibroblasts, ATM is required for efficient replication of MHV68 in mouse macrophages (Tarakanova et al., 2007). Thus, while we did not observe a difference in VZV replication in fibroblasts lacking ATM, ATM might be important for VZV replication in other cell types. "
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    ABSTRACT: Mammalian cells activate DNA damage response pathways in response to virus infections. Activation of these pathways can enhance replication of many viruses, including herpesviruses. Activation of cellular ATM results in phosphorylation of H2AX and recruits proteins to sites of DNA damage. We found that varicella-zoster (VZV) infected cells had elevated levels of phosphorylated H2AX and phosphorylated ATM and that these levels increased in cells infected with VZV deleted for ORF61 or ORF63, but not deleted for ORF67. Expression of VZV ORF61, ORF62, or ORF63 alone did not result in phosphorylation of H2AX. While BGLF4, the Epstein-Barr virus homolog of VZV ORF47 protein kinase, phosphorylates H2AX and ATM, neither VZV ORF47 nor ORF66 protein kinase phosphorylated H2AX or ATM. Cells lacking ATM had no reduction in VZV replication. Thus, VZV induces phosphorylation of H2AX and ATM and this effect is associated with the presence of specific VZV genes in virus-infected cells.
    Virology 03/2014; s 452–453:52–58. DOI:10.1016/j.virol.2013.12.039 · 3.32 Impact Factor
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    • "A common feature of herpesviruses is their capacity to activate DDRs in infected cells (Shirata et al., 2005; Gaspar and Shenk, 2006; Koopal et al., 2007; Tarakanova et al., 2007; Nikitin et al., 2010). Although in some cases this is associated with lytic or productive infection, when the virus has a requirement for rapid replication of its genome prior to virion assembly, at least two gamma-herpesviruses (Kaposi’s Sarcoma associated herpes virus (KSHV, aka HHV8) and EBV) trigger DDRs during the establishment of a latent infection. "
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    ABSTRACT: Viruses that establish a persistent infection, involving intracellular latency, commonly stimulate cellular DNA synthesis and sometimes cell division early after infection. However, most cells of metazoans have evolved "fail-safe" responses that normally monitor unscheduled DNA synthesis and prevent cell proliferation when, for instance, cell proto-oncogenes are "activated" by mutation, amplification, or chromosomal rearrangements. These cell intrinsic defense mechanisms that reduce the risk of neoplasia and cancer are collectively called oncogenic stress responses (OSRs). Mechanisms include the activation of tumor suppressor genes and the so-called DNA damage response that together trigger pathways leading to cell cycle arrest (e.g., cell senescence) or complete elimination of cells (e.g., apoptosis). It is not surprising that viruses that can induce cellular DNA synthesis and cell division have the capacity to trigger OSR, nor is it surprising that these viruses have evolved countermeasures for inactivating or bypassing OSR. The main focus of this review is how the human tumor-associated Epstein-Barr virus manipulates the host polycomb group protein system to control - by epigenetic repression of transcription - key components of the OSR during the transformation of normal human B cells into permanent cell lines.
    Frontiers in Genetics 10/2013; 4:212. DOI:10.3389/fgene.2013.00212
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    • "N36S virus mutant (Hwang et al., 2009; Tarakanova et al., 2007) and wt MHV68 viral stocks were prepared and titered on NIH 3T12 cells as previously described (Mounce et al., 2011b). Wt MHV68 was inactivated by UV crosslinking (0.75 J/cm 2 ; Stratagene UV Stratalinker 1800, Agilent Technologies, Santa Clara, CA) prior to infection. "
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    ABSTRACT: Type I interferon (IFN) is a critical antiviral response of the host. We found that Interferon Regulatory Factor 3 (IRF-3) was responsible for induction of type I IFN following mouse gammaherpesvirus-68 (MHV68) infection of primary macrophages. Intriguingly, type I IFN signaling was maintained throughout the entire MHV68 replication cycle, in spite of several known viral IFN antagonists. However, MHV68-infected primary macrophages displayed attenuated responses to exogenous type I IFN, suggesting that MHV68 controls the level of type I IFN signaling that is allowed to occur during replication. Type I IFN receptor and IRF-3 were necessary to attenuate transcription of MHV68 RTA, an immediate early gene critical for replication. Furthermore, higher constitutive activity of RTA promoters was observed in the absence of type I IFN signaling. Our study suggests that MHV68 has preserved the ability to sense type I IFN status of the host in order to limit lytic replication.
    Virology 05/2013; 443(1). DOI:10.1016/j.virol.2013.04.036 · 3.32 Impact Factor
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