1
|
Ostler JB, Jones C. The Bovine Herpesvirus 1 Latency-Reactivation Cycle, a Chronic Problem in the Cattle Industry. Viruses 2023; 15:552. [PMID: 36851767 PMCID: PMC9966457 DOI: 10.3390/v15020552] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 02/19/2023] Open
Abstract
Bovine alphaherpesvirus 1 (BoHV-1) is a persistent and recurring disease that affects cattle worldwide. It is a major contributor to bovine respiratory disease and reproductive failure in the US. A major complication of BoHV-1 arises from the lifelong latent infection established in the sensory ganglia of the peripheral nervous system following acute infection. Lifelong latency is marked by periodic reactivation from latency that leads to virus transmission and transient immunosuppression. Physiological and environmental stress, along with hormone fluctuations, can drive virus reactivation from latency, allowing the virus to spread rapidly. This review discusses the mechanisms of the latency/reactivation cycle, with particular emphasis on how different hormones directly regulate BoHV-1 gene expression and productive infection. Glucocorticoids, including the synthetic corticosteroid dexamethasone, are major effectors of the stress response. Stress directly regulates BoHV-1 gene expression through multiple pathways, including β-catenin dependent Wnt signaling, and the glucocorticoid receptor. Related type 1 nuclear hormone receptors, the androgen and progesterone receptors, also drive BoHV-1 gene expression and productive infection. These receptors form feed-forward transcription loops with the stress-induced Krüppel-like transcription factors KLF4 and KLF15. Understanding these molecular pathways is critical for developing novel therapeutics designed to block reactivation and reduce virus spread and disease.
Collapse
Affiliation(s)
| | - Clinton Jones
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, OK 74078, USA
| |
Collapse
|
2
|
Toomer G, Workman A, Harrison KS, Stayton E, Hoyt PR, Jones C. Stress Triggers Expression of Bovine Herpesvirus 1 Infected Cell Protein 4 (bICP4) RNA during Early Stages of Reactivation from Latency in Pharyngeal Tonsil. J Virol 2022; 96:e0101022. [PMID: 36416585 PMCID: PMC9749472 DOI: 10.1128/jvi.01010-22] [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: 06/29/2022] [Accepted: 10/31/2022] [Indexed: 11/24/2022] Open
Abstract
Bovine herpesvirus 1 (BoHV-1), an important pathogen of cattle, establishes lifelong latency in sensory neurons within trigeminal ganglia (TG) after acute infection. The BoHV-1 latency-reactivation cycle, like other alphaherpesvirinae subfamily members, is essential for viral persistence and transmission. Notably, cells within pharyngeal tonsil (PT) also support a quiescent or latent BoHV-1 infection. The synthetic corticosteroid dexamethasone, which mimics the effects of stress, consistently induces BoHV-1 reactivation from latency allowing early stages of viral reactivation to be examined in the natural host. Based on previous studies, we hypothesized that stress-induced cellular factors trigger expression of key viral transcriptional regulatory genes. To explore this hypothesis, RNA-sequencing studies compared viral gene expression in PT during early stages of dexamethasone-induced reactivation from latency. Strikingly, RNA encoding infected cell protein 4 (bICP4), which is translated into an essential viral transcriptional regulatory protein, was detected 30 min after dexamethasone treatment. Ninety minutes after dexamethasone treatment bICP4 and, to a lesser extent, bICP0 RNA were detected in PT. All lytic cycle viral transcripts were detected within 3 h after dexamethasone treatment. Surprisingly, the latency related (LR) gene, the only viral gene abundantly expressed in latently infected TG neurons, was not detected in PT during latency. In TG neurons, bICP0 and the viral tegument protein VP16 are expressed before bICP4 during reactivation, suggesting distinct viral regulatory genes mediate reactivation from latency in PT versus TG neurons. Finally, these studies confirm PT is a biologically relevant site for BoHV-1 latency, reactivation from latency, and virus transmission. IMPORTANCE BoHV-1, a neurotropic herpesvirus, establishes, maintains, and reactivates from latency in neurons. BoHV-1 DNA is also detected in pharyngeal tonsil (PT) from latently infected calves. RNA-sequencing studies revealed the viral infected cell protein 4 (bICP4) RNA was expressed in PT of latently infected calves within 30 min after dexamethasone was used to initiate reactivation. As expected, bICP4 RNA was not detected during latency. All lytic cycle viral genes were expressed within 3 h after dexamethasone treatment. Conversely, bICP0 and the viral tegument protein VP16 are expressed prior to bICP4 in trigeminal ganglionic neurons during reactivation. The viral latency related gene, which is abundantly expressed in latently infected neurons, was not abundantly expressed in PT during latency. These studies provide new evidence PT is a biologically relevant site for BoHV-1 latency and reactivation. Finally, we predict other alphaherpesvirinae subfamily members utilize PT as a site for latency and reactivation.
Collapse
Affiliation(s)
- Gabriela Toomer
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, Oklahoma, USA
| | - Aspen Workman
- United States Department of Agriculture, Agricultural Research Service, U.S. Meat Animal Research Center, Clay Center, Nebraska, USA
| | - Kelly S. Harrison
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, Oklahoma, USA
| | - Erin Stayton
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, Oklahoma, USA
| | - Peter R. Hoyt
- Oklahoma State University, Department of Biochemistry and Molecular Biology, Stillwater, Oklahoma, USA
| | - Clinton Jones
- Oklahoma State University, College of Veterinary Medicine, Department of Veterinary Pathobiology, Stillwater, Oklahoma, USA
| |
Collapse
|
3
|
Inhibition of Stress-Induced Viral Promoters by a Bovine Herpesvirus 1 Non-Coding RNA and the Cellular Transcription Factor, β-Catenin. Int J Mol Sci 2021; 22:ijms22020519. [PMID: 33430186 PMCID: PMC7825607 DOI: 10.3390/ijms22020519] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/05/2021] [Accepted: 01/05/2021] [Indexed: 11/30/2022] Open
Abstract
The ability to establish, maintain, and reactivate from latency in sensory neurons within trigeminal ganglia (TG) is crucial for bovine herpesvirus 1 (BoHV-1) transmission. In contrast to lytic infection, the only viral gene abundantly expressed during latency is the latency-related (LR) gene. The synthetic corticosteroid dexamethasone consistently induces reactivation from latency, in part because the glucocorticoid receptor (GR) transactivates viral promoters that drive expression of key viral transcriptional regulator proteins (bICP0 and bICP4). Within hours after dexamethasone treatment of latently infected calves, LR gene products and β-catenin are not readily detected in TG neurons. Hence, we hypothesized that LR gene products and/or β-catenin restrict GR-mediated transcriptional activation. A plasmid expressing LR RNA sequences that span open reading frame 2 (ORF2-Stop) inhibited GR-mediated transactivation of the BoHV-1 immediate early transcription unit 1 (IEtu1) and mouse mammary tumor virus (MMTV) promoter activity in mouse neuroblastoma cells (Neuro-2A). ORF2-Stop also reduced productive infection and GR steady-state protein levels in transfected Neuro-2A cells. Additional studies revealed that the constitutively active β-catenin mutant reduced the transactivation of the IEtu1 promoter by GR and dexamethasone. Collectively, these studies suggest ORF2 RNA sequences and Wnt/β-catenin signaling pathway actively promote maintenance of latency, in part, by impairing GR-mediated gene expression.
Collapse
|
4
|
Marin M, Burucúa M, Rensetti D, Rosales JJ, Odeón A, Pérez S. Distinctive features of bovine alphaherpesvirus types 1 and 5 and the virus-host interactions that might influence clinical outcomes. Arch Virol 2019; 165:285-301. [PMID: 31845150 DOI: 10.1007/s00705-019-04494-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 11/09/2019] [Indexed: 12/14/2022]
Abstract
Bovine herpesvirus types 1 (BoHV-1) and 5 (BoHV-5) are two closely related alphaherpesviruses. BoHV-1 causes several syndromes in cattle, including respiratory disease and sporadic cases of encephalitis, whereas BoHV-5 is responsible for meningoencephalitis in calves. Although both viruses are neurotropic, they differ in their neuropathogenic potential. This review summarizes the findings on the specific mechanisms and pathways known to modulate the pathogenesis of BoHV-1 and BoHV-5, particularly in relation to respiratory and neurological syndromes, which characterize BoHV-1 and BoHV-5 infections, respectively.
Collapse
Affiliation(s)
- Maia Marin
- Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Agropecuaria Balcarce, Ruta 226 Km 73.5, Balcarce, 7620, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rivadavia 1917, C1033AAJ, Buenos Aires, Argentina
| | - Mercedes Burucúa
- Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Agropecuaria Balcarce, Ruta 226 Km 73.5, Balcarce, 7620, Buenos Aires, Argentina.,Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rivadavia 1917, C1033AAJ, Buenos Aires, Argentina
| | - Daniel Rensetti
- Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, Paraje Arroyo Seco S/N, 7000, Tandil, Argentina
| | - Juan José Rosales
- Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, Paraje Arroyo Seco S/N, 7000, Tandil, Argentina.,Centro de Investigación Veterinaria de Tandil (CIVETAN)-CONICET, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, Paraje Arroyo Seco S/N, 7000, Tandil, Argentina
| | - Anselmo Odeón
- Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Agropecuaria Balcarce, Ruta 226 Km 73.5, Balcarce, 7620, Buenos Aires, Argentina
| | - Sandra Pérez
- Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, Paraje Arroyo Seco S/N, 7000, Tandil, Argentina. .,Centro de Investigación Veterinaria de Tandil (CIVETAN)-CONICET, Facultad de Ciencias Veterinarias, Universidad Nacional del Centro de la Provincia de Buenos Aires, Paraje Arroyo Seco S/N, 7000, Tandil, Argentina.
| |
Collapse
|
5
|
Three newly identified Immediate Early Genes of Bovine herpesvirus 1 lack the characteristic Octamer binding motif- 1. Sci Rep 2018; 8:11441. [PMID: 30061689 PMCID: PMC6065388 DOI: 10.1038/s41598-018-29490-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 07/11/2018] [Indexed: 02/06/2023] Open
Abstract
Only three immediate early genes (IE) BICP0, BICP4 and BICP22 of Bovine herpesvirus 1 (BoHV-1) are known. These genes are expressed coordinately and their promoters are well characterized. We provide evidence for expression of three additional IE genes of BoHV-1 i.e. UL21, UL33 and UL34. These genes are expressed in the presence of cycloheximide (CH) at the same time as known IE genes. Surprisingly, the promoters of newly identified IE genes (UL21, UL33, UL34) lack the OCT-1 binding site, a considered site of transactivation of the BoHV-1 IE genes. The other difference in the promoters of the newly identified IE genes is the presence of TATA box at near optimal site. However, all the IE genes have similar spatial placements of C/EBPα, DPE and INR elements.
Collapse
|
6
|
Liu Y, Jones C. Regulation of Notch-mediated transcription by a bovine herpesvirus 1 encoded protein (ORF2) that is expressed in latently infected sensory neurons. J Neurovirol 2016; 22:518-28. [PMID: 26846632 DOI: 10.1007/s13365-015-0394-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 10/02/2015] [Accepted: 10/12/2015] [Indexed: 12/26/2022]
Abstract
Bovine herpesvirus 1 (BoHV-1) is an Alphaherpesvirinae subfamily member that establishes life-long latency in sensory neurons. The latency-related RNA (LR-RNA) is abundantly expressed during latency. An LR mutant virus containing stop codons at the amino-terminus of open reading frame (ORF)2 does not reactivate from latency and replicates less efficiently in tonsils and trigeminal ganglia. ORF2 inhibits apoptosis, interacts with Notch family members, and interferes with Notch-dependent transcription suggesting ORF2 expression enhances survival of infected neurons. The Notch signaling pathway is crucial for neuronal differentiation and survival suggesting that interactions between ORF2 and Notch family members regulate certain aspects of latency. Consequently, for this study, we compared whether ORF2 interfered with the four mammalian Notch family members. ORF2 consistently interfered with Notch1-3-mediated transactivation of three cellular promoters. Conversely, Notch4-mediated transcription was not consistently inhibited by ORF2. Electrophoretic shift mobility assays using four copies of a consensus-DNA binding site for Notch/CSL (core binding factor (CBF)-1, Suppressor of Hairless, Lag-2) as a probe revealed ORF2 interfered with Notch1 and 3 interactions with a CSL family member bound to DNA. Additional studies demonstrated ORF2 enhances neurite sprouting in mouse neuroblastoma cells that express Notch1-3, but not Notch4. Collectively, these studies indicate that ORF2 inhibits Notch-mediated transcription and signaling by interfering with Notch interacting with CSL bound to DNA.
Collapse
Affiliation(s)
- Yilin Liu
- School of Veterinary Medicine and Biomedical Sciences, Nebraska Center for Virology, Morisson Life Science Center, University of Nebraska, Lincoln, Lincoln, NE, 68583-0900, USA
| | - Clinton Jones
- School of Veterinary Medicine and Biomedical Sciences, Nebraska Center for Virology, Morisson Life Science Center, University of Nebraska, Lincoln, Lincoln, NE, 68583-0900, USA. .,Center for Veterinary Health Sciences, Department of Veterinary Pathobiology, Oklahoma State University, 157C McElroy Hall, Stillwater, OK, 74078, USA.
| |
Collapse
|
7
|
β-Catenin, a Transcription Factor Activated by Canonical Wnt Signaling, Is Expressed in Sensory Neurons of Calves Latently Infected with Bovine Herpesvirus 1. J Virol 2016; 90:3148-59. [PMID: 26739046 DOI: 10.1128/jvi.02971-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 12/30/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Like many Alphaherpesvirinae subfamily members, bovine herpesvirus 1 (BoHV-1) expresses an abundant transcript in latently infected sensory neurons, the latency-related (LR)-RNA. LR-RNA encodes a protein (ORF2) that inhibits apoptosis, interacts with Notch family members, interferes with Notch-mediated transcription, and stimulates neurite formation in cells expressing Notch. An LR mutant virus containing stop codons at the amino terminus of ORF2 does not reactivate from latency or replicate efficiently in certain tissues, indicating that LR gene products are important. In this study, β-catenin, a transcription factor activated by the canonical Wnt signaling pathway, was frequently detected in ORF2-positive trigeminal ganglionic neurons of latently infected, but not mock-infected, calves. Conversely, the lytic cycle regulatory protein (BoHV-1 infected cell protein 0, or bICP0) was not frequently detected in β-catenin-positive neurons in latently infected calves. During dexamethasone-induced reactivation from latency, mRNA expression levels of two Wnt antagonists, Dickkopf-1 (DKK-1) and secreted Frizzled-related protein 2 (SFRP2), were induced in bovine trigeminal ganglia (TG), which correlated with reduced β-catenin protein expression in TG neurons 6 h after dexamethasone treatment. ORF2 and a coactivator of β-catenin, mastermind-like protein 1 (MAML1), stabilized β-catenin protein levels and stimulated β-catenin-dependent transcription in mouse neuroblastoma cells more effectively than MAML1 or ORF2 alone. Neuroblastoma cells expressing ORF2, MAML1, and β-catenin were highly resistant to cell death following serum withdrawal, whereas most cells transfected with only one of these genes died. The Wnt signaling pathway interferes with neurodegeneration but promotes neuronal differentiation, suggesting that stabilization of β-catenin expression by ORF2 promotes neuronal survival and differentiation. IMPORTANCE Bovine herpesvirus 1 (BoHV-1) is an important pathogen of cattle, and like many Alphaherpesvirinae subfamily members establishes latency in sensory neurons. Lifelong latency and the ability to reactivate from latency are crucial for virus transmission. Maintaining the survival and normal functions of terminally differentiated neurons is also crucial for lifelong latency. Our studies revealed that BoHV-1 gene products expressed during latency stabilize expression of the transcription factor β-catenin and perhaps its cofactor, mastermind-like protein 1 (MAML1). In contrast to expression during latency, β-catenin expression in sensory neurons is not detectable following treatment of latently infected calves with the synthetic corticosteroid dexamethasone to initiate reactivation from latency. A viral protein (ORF2) expressed in a subset of latently infected neurons stabilized β-catenin and MAML1 in transfected cells. ORF2, β-catenin, and MAML1 also enhanced cell survival when growth factors were withdrawn, suggesting that these genes enhance survival of latently infected neurons.
Collapse
|
8
|
Jones C. Bovine Herpes Virus 1 (BHV-1) and Herpes Simplex Virus Type 1 (HSV-1) Promote Survival of Latently Infected Sensory Neurons, in Part by Inhibiting Apoptosis. J Cell Death 2013; 6:1-16. [PMID: 25278776 PMCID: PMC4147773 DOI: 10.4137/jcd.s10803] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
α-Herpesvirinae subfamily members, including herpes simplex virus type 1 (HSV-1) and bovine herpes virus 1 (BHV-1), initiate infection in mucosal surfaces. BHV-1 and HSV-1 enter sensory neurons by cell-cell spread where a burst of viral gene expression occurs. When compared to non-neuronal cells, viral gene expression is quickly extinguished in sensory neurons resulting in neuronal survival and latency. The HSV-1 latency associated transcript (LAT), which is abundantly expressed in latently infected neurons, inhibits apoptosis, viral transcription, and productive infection, and directly or indirectly enhances reactivation from latency in small animal models. Three anti-apoptosis genes can be substituted for LAT, which will restore wild type levels of reactivation from latency to a LAT null mutant virus. Two small non-coding RNAs encoded by LAT possess anti-apoptosis functions in transfected cells. The BHV-1 latency related RNA (LR-RNA), like LAT, is abundantly expressed during latency. The LR-RNA encodes a protein (ORF2) and two microRNAs that are expressed in certain latently infected neurons. Wild-type expression of LR gene products is required for stress-induced reactivation from latency in cattle. ORF2 has anti-apoptosis functions and interacts with certain cellular transcription factors that stimulate viral transcription and productive infection. ORF2 is predicted to promote survival of infected neurons by inhibiting apoptosis and sequestering cellular transcription factors which stimulate productive infection. In addition, the LR encoded microRNAs inhibit viral transcription and apoptosis. In summary, the ability of BHV-1 and HSV-1 to interfere with apoptosis and productive infection in sensory neurons is crucial for the life-long latency-reactivation cycle in their respective hosts.
Collapse
Affiliation(s)
- Clinton Jones
- School of Veterinary Medicine and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Morrison Life Science Center, Lincoln, NE
| |
Collapse
|
9
|
A protein (ORF2) encoded by the latency-related gene of bovine herpesvirus 1 interacts with DNA. J Virol 2013; 87:5493-501. [PMID: 23468493 DOI: 10.1128/jvi.00193-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bovine herpesvirus 1 (BHV-1), like other members of the Alphaherpesvirinae subfamily, establishes latency in sensory neurons. The virally encoded latency-related RNA (LR-RNA) is expressed abundantly in latently infected sensory neurons and encodes several proteins, including ORF2. An LR mutant virus with stop codons at the amino terminus of ORF2 does not reactivate from latency after treatment with the synthetic corticosteroid dexamethasone, in part because it induces higher levels of apoptosis during the establishment of latency. ORF2 inhibits apoptosis, interacts with three cellular transcription factors (Notch1, Notch3, and C/EBP-α), and interferes with Notch-mediated signaling. Consequently, we predict that ORF2 expression is crucial for the latency reactivation cycle in cattle. In this study, we tested whether ORF2 interacts with nucleic acids, because it contains 18% basic amino acids and localizes to the nucleus. A subset of ORF2 proteins was associated with chromatin and preferentially associated with single-stranded DNA in transfected neuroblastoma cells (Neuro-2A). Alanine substitution of serine, threonine, and tyrosine residues in ORF2 increased the steady-state protein levels in Neuro-2A cells, and this protein preferentially interacted with double-stranded DNA. Certain in-frame transposon insertion mutants did not interact with DNA as efficiently as wild-type (wt) ORF2 did. ORF2 purified from bacteria under denaturing conditions preferentially interacted with double-stranded DNA, suggesting that the interaction between ORF2 and DNA was direct. In contrast, ORF2 purified under native conditions preferentially interacted with single-stranded DNA. We suggest that interactions between ORF2 and DNA mediate certain aspects of the latency reactivation cycle.
Collapse
|
10
|
Sinani D, Jones C. Localization of sequences in a protein (ORF2) encoded by the latency-related gene of bovine herpesvirus 1 that inhibits apoptosis and interferes with Notch1-mediated trans-activation of the bICP0 promoter. J Virol 2011; 85:12124-33. [PMID: 21937659 PMCID: PMC3209353 DOI: 10.1128/jvi.05478-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 09/09/2011] [Indexed: 12/13/2022] Open
Abstract
Bovine herpesvirus 1 (BHV-1) infection induces clinical symptoms in the upper respiratory tract, inhibits immune responses, and can result in life-threatening secondary bacterial infections. Following acute infection, BHV-1 establishes latency in sensory neurons within trigeminal ganglia. Periodically, reactivation from latency occurs, resulting in virus transmission. The latency-related (LR) RNA is abundantly expressed in latently infected sensory neurons, suggesting that LR gene products regulate the latency-reactivation cycle. An LR mutant virus with stop codons at the amino terminus of the first open reading frame (ORF) in the LR gene (ORF2) does not reactivate from latency, in part because it induces higher levels of apoptosis in infected neurons. ORF2 inhibits apoptosis in transiently transfected cells, suggesting that it plays an important role in the latency-reactivation cycle. ORF2 also interacts with Notch1 or Notch3 and consequently inhibits their ability to trans-activate the bICP0 early and glycoprotein C promoters. In this study, we identified ORF2 sequences that were necessary for inhibiting cold shock-induced apoptosis or Notch1-mediated trans-activation of the bICP0 early promoter and stimulation of productive infection. Relative to ORF2 sequences necessary for inhibiting apoptosis, distinct domains in ORF2 were important for interfering with Notch1-mediated trans-activation. Five consensus protein kinase A and/or protein kinase C phosphorylation sites within ORF2 regulate the steady-state levels of ORF2 in transfected cells. A nuclear localization signal in ORF2 was necessary for inhibiting Notch1-mediated trans-activation but not apoptosis. In summary, ORF2 has more than one functional domain that regulates its stability and functional properties.
Collapse
Affiliation(s)
- Devis Sinani
- School of Veterinary Medicine and Biomedical Sciences & Nebraska Center for Virology, University of Nebraska, Lincoln, Ken Morrison Life Sciences Center, RM234, Lincoln, Nebraska 68583-0900
| | - Clinton Jones
- School of Veterinary Medicine and Biomedical Sciences & Nebraska Center for Virology, University of Nebraska, Lincoln, Ken Morrison Life Sciences Center, RM234, Lincoln, Nebraska 68583-0900
| |
Collapse
|
11
|
da Silva LF, Jones C. Infection of cultured bovine cells with bovine herpesvirus 1 (BHV-1) or Sendai virus induces different beta interferon subtypes. Virus Res 2011; 157:54-60. [PMID: 21316405 PMCID: PMC3078687 DOI: 10.1016/j.virusres.2011.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2011] [Revised: 02/03/2011] [Accepted: 02/03/2011] [Indexed: 12/21/2022]
Abstract
In contrast to mice or humans, cattle contain three beta interferon (IFN-β) genes with distinct transcriptional promoters suggesting IFN-β gene expression is not stimulated the same by different viruses. To test this hypothesis, we compared expression of the three IFN-β subtypes after infection with a RNA virus, Sendai, versus a large DNA virus, bovine herpesvirus 1 (BHV-1). Infection of low passage bovine kidney (BK) or established bovine kidney cells (CRIB) with Sendai virus has consistently led to high levels of IFN-β1 RNA. Conversely, infection of CRIB cells, but not BK cells, with BHV-1 increased IFN-β3 RNA levels and to a lesser extent the other two IFN-β subtypes. Inhibition of de novo protein synthesis with cycloheximide resulted in higher levels of IFN-β1 and IFN-β2 RNA levels after BHV-1 infection. Further studies demonstrated that BHV-1 immediate early and/or early genes were primarily responsible for inhibiting the IFN response in BK cells. The three bovine IFN-β promoters were cloned upstream of a reporter gene construct, and their properties analyzed in transient transfection assays. Only the IFN-β3 promoter was trans-activated by IRF3 (interferon responsive factor 3). IRF7 and double stranded RNA (polyI:C) stimulated IFN-β1 and IFN-β3 promoter activity, but not IFN-β2. Relative to the human IFN-β promoter, the IFN-β3 promoter contained fewer nucleotide differences in the positive regulatory domain III (PRD III), PRD IV, and PRD I compared to the IFN-β1 and IFN-β2 promoter. Collectively, these studies provide evidence that virus infection differentially stimulates expression of the three bovine IFN-β genes.
Collapse
Affiliation(s)
- Leticia Frizzo da Silva
- School of Veterinary Medicine and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, Fair Street at East Campus Loop, Lincoln, NE, 68583-0905, Phone: (402) 472-1890, FAX: (402) 472-9690
| | - Clinton Jones
- School of Veterinary Medicine and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, Fair Street at East Campus Loop, Lincoln, NE, 68583-0905, Phone: (402) 472-1890, FAX: (402) 472-9690
| |
Collapse
|
12
|
Szpara ML, Kobiler O, Enquist LW. A common neuronal response to alphaherpesvirus infection. J Neuroimmune Pharmacol 2010; 5:418-27. [PMID: 20401540 PMCID: PMC2990883 DOI: 10.1007/s11481-010-9212-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 03/12/2010] [Indexed: 12/11/2022]
Abstract
Alphaherpesviruses are a subfamily of the Herpesviridae that can invade the nervous system and establish either lytic or latent infections. The establishment of latent infection can occur only in neurons, indicating a unique virus-host interaction in these cells. Here, we compare results from seven microarray studies that focused on the host response of either neural tissue or isolated neurons to alphaherpesvirus infection. These studies utilized either herpes simplex virus type 1 or pseudorabies virus as the infectious agent. From these data, we have found common host responses spanning a variety of infection models in different species, with different herpesvirus strains, and during all phases of infection including lytic, latent, and reactivation. The repeated observation of transcriptional effects on these genes and gene families indicates their likely importance in host defenses or the viral infectious process. We discuss the possible role of these different genes and genes families in alphaherpesvirus infection.
Collapse
Affiliation(s)
- Moriah L. Szpara
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, 314 Schultz Laboratory, Princeton NJ 08544, USA,
| | - Oren Kobiler
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, 314 Schultz Laboratory, Princeton NJ 08544, USA,
| | - Lynn W. Enquist
- Department of Molecular Biology and Princeton Neuroscience Institute, Princeton University, 314 Schultz Laboratory, Princeton NJ 08544, USA,
| |
Collapse
|
13
|
Dexamethasone treatment of calves latently infected with bovine herpesvirus 1 leads to activation of the bICP0 early promoter, in part by the cellular transcription factor C/EBP-alpha. J Virol 2009; 83:8800-9. [PMID: 19553330 DOI: 10.1128/jvi.01009-09] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sensory neurons within trigeminal ganglia (TG) are the primary site for bovine herpesvirus 1 (BHV-1) latency. During latency, viral gene expression is restricted to the latency-related (LR) gene and the open reading frame ORF-E. We previously constructed an LR mutant virus that expresses LR RNA but not any of the known LR proteins. In contrast to calves latently infected with wild-type (wt) BHV-1 or the LR rescued virus, the LR mutant virus does not reactivate from latency following dexamethasone (DEX) treatment. In this study, we demonstrated that bICP0, but not bICP4, transcripts were consistently detected in TG of calves infected with the LR mutant or LR rescued virus following DEX treatment. Calves latently infected with the LR rescued virus but not the LR mutant virus expressed late transcripts, which correlated with shedding of infectious virus following DEX treatment. The bICP4 and bICP0 genes share a common immediate-early promoter, suggesting that this promoter was not consistently activated during DEX-induced reactivation from latency. The bICP0 gene also contains a novel early promoter that was activated by DEX in mouse neuroblastoma cells. Expression of a cellular transcription factor, C/EBP-alpha, was stimulated by DEX, and C/EBP-alpha expression was necessary for DEX induction of bICP0 early promoter activity. C/EBP-alpha directly interacted with bICP0 early promoter sequences that were necessary for trans activation by C/EBP-alpha. In summary, DEX treatment of latently infected calves induced cellular factors that stimulated bICP0 early promoter activity. Activation of bICP0 early promoter activity does not necessarily lead to late gene expression and virus shedding.
Collapse
|