scholarly journals Bovine herpesvirus 1 immediate-early protein (bICP0) interacts with the histone acetyltransferase p300, which stimulates productive infection and gC promoter activity

2006 ◽  
Vol 87 (7) ◽  
pp. 1843-1851 ◽  
Author(s):  
Yange Zhang ◽  
Yunquan Jiang ◽  
Vicki Geiser ◽  
Joe Zhou ◽  
Clinton Jones

The immediate-early protein, bICP0, of Bovine herpesvirus 1 (BHV-1) transactivates viral promoters and stimulates productive infection. bICP0 is expressed constitutively during productive infection, as its gene contains an immediate-early and an early promoter. Like other ICP0 homologues encoded by members of the subfamily Alphaherpesvirinae, bICP0 contains a zinc RING finger located near its N terminus. Mutations that disrupt the bICP0 zinc RING finger impair its ability to activate transcription, stimulate productive infection, inhibit interferon-dependent transcription in certain cell types and regulate subnuclear localization. bICP0 also interacts with a cellular chromatin-remodelling enzyme, histone deacetylase 1 (HDAC1), and can relieve HDAC1-mediated transcriptional repression, suggesting that bICP0 inhibits silencing of the viral genome. In this study, it was shown that bICP0 interacted with the histone acetyltransferase p300 during productive infection and in transiently transfected cells. In addition, p300 enhanced BHV-1 productive infection and transactivated a late viral promoter (gC). In contrast, a CH3-domain deletion mutant of p300, which is a dominant-negative mutant, did not activate the gC promoter. bICP0 and p300 cooperated to activate the gC promoter, suggesting that there is a synergistic effect on promoter activation. As p300 can activate certain antiviral signalling pathways (for example, interferon), it was hypothesized that interactions between p300 and bICP0 may dampen the antiviral response following infection.

2001 ◽  
Vol 75 (20) ◽  
pp. 9571-9578 ◽  
Author(s):  
Yange Zhang ◽  
Clinton Jones

ABSTRACT Infected-cell protein 0 encoded by bovine herpesvirus 1 (BHV-1) (bICP0) is necessary for efficient productive infection, in large part, because it activates all 3 classes of BHV-1 genes (U. V. Wirth, C. Fraefel, B. Vogt, C. Vlcek, V. Paces, and M. Schwyzer, J. Virol. 66:2763–2772, 1992). Although bICP0 is believed to be a functional homologue of herpes simplex virus type 1-encoded ICP0, the only well-conserved domain between the proteins is a zinc ring finger located near the amino terminus of both proteins. Our previous studies demonstrated that bICP0 is toxic to transfected cells but does not appear to directly induce apoptosis (Inman, M., Y. Zhang, V. Geiser, and C. Jones, J. Gen. Virol. 82:483–492, 2001). C-terminal sequences in the last 320 amino acids of bICP0 mediate subcellular localization. Mutagenesis of the zinc ring finger within bICP0 revealed that this domain was important for transcriptional activation. In this study, we demonstrate that bICP0 interacts with histone deacetylase 1 (HDAC1), which results in activation of a simple promoter containing four consensus Myc-Max binding sites. The interaction between bICP0 and HDAC1 correlated with inhibition of Mad-dependent transcriptional repression. In resting CV-1 cells, bICP0 relieved HDAC1-mediated transcriptional repression. The zinc ring finger was required for relieving HDAC1-induced repression but not for interacting with HDAC1. In fetal bovine lung cells but not in a human epithelial cell line, bICP0 expression correlated with reduced steady-state levels of HDAC1 in crude cytoplasmic extracts. We hypothesize that the ability of bICP0 to overcome HDAC1-induced repression plays a role in promoting productive infection in highly differentiated cell types.


2018 ◽  
Vol 92 (17) ◽  
Author(s):  
Laximan Sawant ◽  
Insun Kook ◽  
Jodi L. Vogel ◽  
Thomas M. Kristie ◽  
Clinton Jones

ABSTRACTFollowing productive infection, bovine herpesvirus 1 (BoHV-1) establishes latency in sensory neurons. As in other alphaherpesviruses, expression of BoHV-1 immediate early (IE) genes is regulated by an enhancer complex containing the viral IE activator VP16, the cellular transcription factor Oct-1, and transcriptional coactivator HCF-1, which is assembled on an IE enhancer core element (TAATGARAT). Expression of the IE transcription unit that encodes the viral IE activators bICP0 and bICP4 may also be induced by the activated glucocorticoid receptor (GR) via two glucocorticoid response elements (GREs) located upstream of the enhancer core. Strikingly, lytic infection and reactivation from latency are consistently enhanced by glucocorticoid treatmentin vivo. As the coactivator HCF-1 is essential for IE gene expression of alphaherpesviruses and recruited by multiple transcription factors, we tested whether HCF-1 is required for glucocorticoid-induced IE gene expression. Depletion of HCF-1 reduced GR-mediated activation of the IE promoter in mouse neuroblastoma cells (Neuro-2A). More importantly, HCF-1-mediated GR activation of the promoter was dependent on the presence of GRE sites but independent of the TAATGARAT enhancer core element. HCF-1 was also recruited to the GRE region of a promoter lacking the enhancer core, consistent with a direct role of the coactivator in mediating GR-induced transcription. Similarly, during productive lytic infection, HCF-1 and GR occupied the IE region containing the GREs. These studies indicate HCF-1 is critical for GR activation of the viral IE genes and suggests that glucocorticoid induction of viral reactivation proceeds via an HCF-1–GR mechanism in the absence of the viral IE activator VP16.IMPORTANCEBoHV-1 transcription is rapidly activated during stress-induced reactivation from latency. The immediate early transcription unit 1 (IEtu1) promoter is regulated by the GR via two GREs. The IEtu1 promoter regulates expression of two viral transcriptional regulatory proteins, infected cell proteins 0 and 4 (bICP0 and bICP4), and thus must be stimulated during reactivation. This study demonstrates that activation of the IEtu1 promoter by the synthetic corticosteroid dexamethasone requires HCF-1. Interestingly, the GRE sites, but not the IE enhancer core element (TAATGARAT), were required for HCF-1-mediated GR promoter activation. The GR and HCF-1 were recruited to the IEtu1 promoter in transfected and infected cells. Collectively, these studies indicate that HCF-1 is critical for GR activation of the viral IE genes and suggest that an HCF-1–GR complex can stimulate the IEtu1 promoter in the absence of the viral IE activator VP16.


2005 ◽  
Vol 86 (4) ◽  
pp. 879-886 ◽  
Author(s):  
Yange Zhang ◽  
Joe Zhou ◽  
Clinton Jones

It is believed that the bICP0 protein encoded by bovine herpesvirus 1 (BoHV-1) stimulates productive infection by activating viral gene expression. Like the other ICP0-like proteins encoded by alphaherpesvirinae subfamily members, bICP0 contains a zinc RING finger near its amino terminus. The zinc RING finger of bICP0 activates viral transcription, stimulates productive infection, and is toxic to certain cell types. Apart from the zinc RING finger, bICP0 possesses little similarity to the herpes simplex virus type 1 ICP0 protein making it difficult to predict what regions of bICP0 are important. To begin to identify bICP0 functional domains that are not part of the zinc RING finger, a panel of transposon insertion mutants that span bICP0 was developed. A large domain spanning aa 78–256, and a separate domain that is at or near aa 457 was necessary for efficient transactivation of a simple promoter. Transposon insertion at aa 91 impaired bICP0 protein stability in transfected cells. Insertion of transposons into the acidic domain of bICP0 had little or no effect on transactivation of a simple promoter or protein expression suggesting this region does not play a major role in activating gene expression. Sequences near the C terminus (aa 607–676) contain a functional nuclear localization signal. Collectively, these studies indicated that bICP0 contains several important functional domains: (i) the zinc RING finger, (ii) two separate domains that activate transcription, and (iii) a C-terminal nuclear localization signal that is also necessary for efficient transactivation.


2006 ◽  
Vol 113 (3-4) ◽  
pp. 185-192 ◽  
Author(s):  
Okay Saydam ◽  
Florian Steiner ◽  
Bernd Vogt ◽  
Martin Schwyzer

2005 ◽  
Vol 86 (10) ◽  
pp. 2697-2702 ◽  
Author(s):  
Gail Henderson ◽  
Yange Zhang ◽  
Clinton Jones

The infected cell protein 0 (bICP0) encoded by Bovine herpesvirus 1 (BHV-1) stimulates viral gene expression and productive infection. As bICP0 is expressed constitutively during productive infection, it is considered to be the major viral regulatory protein. Like other alphaherpesvirus ICP0 homologues, bICP0 contains a zinc RING finger near its N terminus that activates transcription and regulates subcellular localization. In this study, evidence is provided that bICP0 represses the human beta interferon (IFN-β) promoter and a simple promoter with consensus IFN-stimulated response elements following stimulation with double-stranded RNA (polyinosinic–polycytidylic acid), IFN regulatory factor 3 (IRF3) or IRF7. bICP0 also inhibits the ability of two protein kinases (TBK1 and IKKε) to activate IFN-β promoter activity. The zinc RING finger is necessary for inhibiting IFN-dependent transcription in certain cell types. Collectively, these studies suggest that bICP0 activates productive infection by stimulating viral gene expression and inhibiting IFN-dependent transcription.


2010 ◽  
Vol 111 (2) ◽  
pp. 333-342 ◽  
Author(s):  
Filomena Fiorito ◽  
Gabriella Marfè ◽  
Giovanna E. Granato ◽  
Roberto Ciarcia ◽  
Emma De Blasio ◽  
...  

2007 ◽  
Vol 81 (7) ◽  
pp. 3077-3086 ◽  
Author(s):  
Kazima Saira ◽  
You Zhou ◽  
Clinton Jones

ABSTRACT The ICP0 protein (bICP0) encoded by bovine herpesvirus 1 is the major viral regulatory protein because it stimulates all viral promoters and, consequently, productive infection. Like other ICP0 analogues encoded by Alphaherpesvirinae subfamily members, bICP0 contains a zinc RING finger near its amino terminus that is necessary for activating transcription, regulating subcellular localization, and inhibiting interferon-dependent transcription. In this study, we discovered that sequences near the C terminus, and the zinc RING finger, are necessary for inhibiting the human beta interferon (IFN-β) promoter. In contrast to herpes simplex virus type 1-encoded ICP0, bICP0 reduces interferon response factor 3 (IRF3), but not IRF7, protein levels in transiently transfected cells. The zinc RING finger and sequences near the C terminus are necessary for bICP0-induced degradation of IRF3. A proteasome inhibitor, lactacystin, interfered with bICP0-induced degradation of IRF3, suggesting that bICP0, directly or indirectly, targets IRF3 for proteasome-dependent degradation. IRF3, but not IRF7, is not readily detectable in the nuclei of productively infected bovine cells during the late stages of infection. In the context of productive infection, IRF3 and IRF7 are detected in the nucleus at early times after infection. At late times after infection, IRF7, but not IRF3, is still detectable in the nuclei of infected cells. Collectively, these studies suggest that the ability of bICP0 to reduce IRF3 protein levels is important with respect to disarming the IFN response during productive infection.


2008 ◽  
Vol 82 (24) ◽  
pp. 12060-12068 ◽  
Author(s):  
Kazima Saira ◽  
Shafiqul Chowdhury ◽  
Natasha Gaudreault ◽  
Leticia da Silva ◽  
Gail Henderson ◽  
...  

ABSTRACT Bovine herpesvirus 1 (BHV-1) infected cell protein 0 (bICP0) stimulates productive infection, in part by activating viral gene expression. The C3HC4 zinc RING finger of bICP0 is crucial for activating viral transcription and productive infection. In this study, we used a bacterial artificial chromosome containing a wild-type (wt) virulent BHV-1 strain to generate a single amino acid mutation in the C3HC4 zinc RING finger of bICP0. This virus (the 51g mutant) contains a cysteine-to-glycine mutation (51st amino acid) in the C3HC4 zinc RING finger of bICP0. A plasmid expressing the 51g mutant protein did not transactivate viral promoter activity as efficiently as wt bICP0. The 51g mutant virus expressed higher levels of the bICP0 protein than did the 51g rescued virus (51gR) but yielded reduced virus titers following infection of permissive bovine cells. The 51g mutant virus, but not the 51gR virus, grew poorly in bovine cells pretreated with imiquimod to stimulate interferon production. During acute infection of calves, levels of infectious virus were 2 to 3 logs lower in ocular or nasal swabs with 51g than with 51gR. Calves latently infected with the 51g mutant did not reactivate from latency because virus shedding did not occur in ocular or nasal cavities. As expected, calves latently infected with 51gR reactivated from latency following dexamethasone treatment. These studies demonstrate that mutation of a single well-conserved cysteine residue in the C3HC4 zinc RING finger of bICP0 has dramatic effects on the growth properties of BHV-1.


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