Progress 09/01/08 to 08/31/11
Outputs
OUTPUTS: Bovine herpesvirus 1 (BHV-1), an alpha-herpesvirinae subfamily member, establishes a life-long latent infection in sensory neurons. Periodically, BHV-1 reactivates from latency, infectious virus is spread, and consequently virus transmission occurs. BHV-1 acute infection causes upper respiratory track infections and conjunctivitis in infected cattle. As a result of transient immune-suppression, BHV-1 infections can also lead to life-threatening secondary bacterial pneumonia that is referred to as bovine respiratory disease. The infected cell protein 0 (bICP0) encoded by BHV-1 reduces human beta-interferon (IFN-b) promoter activity, in part, by inducing degradation of interferon response factor 3 (IRF3) and interacting with IRF7. In contrast to humans, cattle contain three IFN-b genes. All three bovine IFN-b proteins have anti-viral activity: but each IFN-b gene has a distinct transcriptional promoter. We have recently cloned and characterized the three bovine IFN-b promoters. Relative to the human IFN-b promoter, each of the three IFN-b promoters contain differences in the four positive regulatory domains that are required for virus-induced activity. In this study, we demonstrate that bICP0 effectively inhibits bovine IFN-b promoter activity following transfection of low passage bovine cells with interferon response factor 3 (IRF3) or IRF7. A bICP0 mutant that localizes to the cytoplasm inhibits bovine IFN-b promoter activity as efficiently as wt bICP0. The cytoplasmic localized bICP0 protein also induced IRF3 degradation with similar efficiency as wt bICP0. Additional studies have identified functional domains in bICP0 that are important for stimulating productive infection, viral transcription, and regulating innate immune responses. PARTICIPANTS: Natasha Gaudreault, Leticia Frizzo da Silva, Gail Henderson TARGET AUDIENCES: Innate immunologists, cattle producers, virologists, and veterinarians. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
These findings help us to understand the mechanism by which bICP0 controls virulence and productive infection. This information will be used to develop superior modified live vaccines.
Publications
- Gaudreault, N. and C. Jones. 2011. Regulation of promyelocytic leukemia (PML) protein levels and cell morphology by bovine herpesvirus 1 infected cell protein 0 (bICP0) and mutant bICP0 proteins that do not localize to the nucleus. Virus Research, 156:17-24.
- Frizzo da Silva, L. and C. Jones. 2011. Infection of cultured bovine cells with bovine herpesvirus 1 (BHV-1) or Sendai virus induces different beta interferon subtypes. Virus Research, 157: 54-60.
- Frizzo da Silva, L.F., N. Gaudreault, and C. Jones. 2011. Cytoplasmic localized infected cell protein 0 (bICP0) encoded by bovine herpesvirus 1 inhibits beta interferon promoter activity and reduces IRF3 (interferon response factor 3) protein levels. Virus Research 169:143-149.
- Chowdhury, S. and C. Jones. 2010. Bovine herpesvirus type 1 (BHV-1) is an important cofactor in the bovine respiratory disease complex. Veterinary Clinics of North America, Food Animal Practice, Bovine Respiratory Disease, eds V.L. Cooper and B. Broderson, 303-321.
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: BHV-1 is a significant viral pathogen of cattle that can induce respiratory disease, abortion, or occasionally encephalitis. BHV-1 is also frequently found in buffalo, which is a growing food animal source in the US. BHV-1 is an important causative agent of "Shipping Fever" or Bovine Respiratory Disease Complex (BRDC). BRDC costs the cattle industry suffers more than $1 billion/year in losses. BHV-1 typically initiates infection in mucosal epithelial surfaces located in the eyes, nose, mouth, upper respiratory tract, or genital tract. Extensive viral gene expression occurs, virus is shed, and clinical symptoms are apparent. Virus then enters the peripheral nervous system, where it establishes a latent infection in sensory neurons. Viral DNA can persist in a latent state for the lifetime of the infected host or it can periodically reactivate. In contrast to the 70-80 viral genes expressed in epithelial cells, only one small region of the viral genome is transcriptionally active in latently infected neurons. This region is designated the latency related (LR) gene. Expression of LR gene products is necessary for the latency-reactivation cycle. The goals of these studies are to understand how the LR gene regulates latency, how a viral transcriptional activator, bICP0, regulates productive infection, and how to develop better vaccines against BHV-1. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
bICP0 sequesters a cellular transcription factor (IRF7) that is important for activating interferon (IFN) expression. A study describing these results was published in the J of Virology (2). Our previous studies have demonstrated that bICP0 interferes with interferon (IFN)-dependent transcription. There are three IFN-β genes in bovine, which is distinct to mice and humans. We have cloned the transcriptional promoters of the bovine IFN-β promoters and characterized these promoters. The bovine IFN-β3 promoter is strongly induced by stimuli that activate IFN expression when compared to the bovine IFN-β1 promoter. Conversely, the bovine IFN-β2 promoter is not efficiently stimulated. A revised manuscript describing these studies was recently submitted to the Journal of General Virology. bICP0 strongly represses the bovine IFN-β1 and 3 promoters. Domains of bICP0 that regulate this process have been mapped. A manuscript describing these studies is in the final stages of preparation. We have demonstrated that bICP0, in the absence of other viral genes, interacts with sub-nuclear structures (ND10), which function in the anti-viral response. The domains of bICP0 that regulate the interaction with PML have also been performed. Finally, these studies have suggested that PML can reduce the efficiency of BHV-1. A manuscript describing these studies is in the final stages of preparation. We have provided evidence that the bICP0 early promoter is preferentially activated during reactivation from latency. A manuscript describing these studies was published recently (4). The bICP0 early promoter is activated more than 100 fold by a cellular transcriptional factor that controls cell cycle progression (E2F1). We also identified two E2F responsive regions within this promoter. A manuscript describing these studies was published this year (8). We have also demonstrated that another viral gene, bICP27, has the potential to inhibit IFN dependent gene expression using the bovine IFN-b promoters. This is significant because it expands the ability of BHV-1 to inhibit innate immune responses.
Publications
- 1. Saira, K., Y. Zhou, and C. Jones. 2009. The infected cell protein 0 encoded by bovine herpesvirus 1 (bICP0) associates with interferon regulatory factor 7 (IRF7), and consequently inhibits beta interferon promoter activity. Journal of Virology. 83:3977-3981.
- 2.Meyer, F. and C. Jones. 2009. C/EBP-alpha cooperates with bTIF to activate the bovine herpesvirus 1 immediate early transcription unit 1 promoter. J. Neurovirology 15:123-130.
- 3. Workman, A., S. Perez, A. Doster, and C. Jones. 2009. Dexamethasone treatment of calves latently infected with bovine herpesvirus 1 (BHV-1) leads to activation of the bICP0 early promoter, in part by the cellular transcription factor C/EBP-alpha. J. Virology, 83:8800-8809. 4. Jones, C. 2009. Regulation of Innate Immune Responses by Bovine Herpesvirus 1 and Infected Cell Protein 0 (bICP0). Viruses 1:255-275.
- 5. Ellis, J., S. Gow, N. Goji, C. Jones, A. Workman, G. Henderson, G. Alaniz, and T. Meinert. 2009. Efficacy of a combination viral vaccine in protecting cattle from experimental infection with bovine herpesviruses-1 isolated from recent vaccine breaks. J of American Veterinary Medical Association, 235:563-572.
- 6. Jaber, T., A. Workman, and C. Jones. Small non-coding RNAs encoded within the bovine herpesvirus 1 latency related gene can reduce steady state levels of infected cell protein 0 (bICP0). 2010. J Virology, 84: 6297-6307.
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Progress 09/01/08 to 08/31/09
Outputs
OUTPUTS: 1. Developed a virus strain with a mutation in the bICP0 gene. This mutant contains an amino acid substitution in the zinc RING finger. This mutant virus grows less efficiently in cultured cells and in calves. Clinical symptoms are not sever in calves, and the calves do not reactivate from latency. This study was published in the Journal of Virology. 2. Discovered that bICP0 interacts with a cellular transcription factor (IRF7) that regulates innate immune responses. This study was published in the Journal of Virology. 3. Determined that a cellular transcription factor (C/EBP-alpha) is induced during reactivation, and activates the bICP0 early promoter. This correlates with the finding that bICP0 transcription is consistently detected during reactivation from latency. This study was published in the Journal of Virology. 4. We have demonstrated that bICP0 induces degradation of a protein (PML) that regulates innate immune responses. PARTICIPANTS: Aspen Workman and Kazima Saira are graduate students who have assisted with the studies in this project. Gail Henderson, my lab manager, has also assisted with these studies. TARGET AUDIENCES: Virologists, immunologists, pharmaceutical companies, and ranchers. PROJECT MODIFICATIONS: Nothing significant
Impacts
We are developing a detailed understanding of how bICP0 regulates viral transcription and innate immune responses. Teh use of the bacterial artificial chromosome (BAC) containing the BHV-1 genome was important for constructing the mutant. This is new technology for constructing viral mutants.
Publications
- Saira, K., S. Chowdhury, N. Gaudreault, L. da Silva, G. Henderson, A. Doster, & C. Jones. 2008. The zinc RING finger of the bovine herpesvirus 1 encoded bICP0 protein is crucial for viral replication and virulence. J. Virology, 82:12060-12068.
- Saira, K., Y. Zhou, and C. Jones. 2009. The infected cell protein 0 encoded by bovine herpesvirus 1 (bICP0) associates with interferon regulatory factor 7 (IRF7), and consequently inhibits beta interferon promoter activity. J. Virology. 83:3977-3981.
- Meyer, F. and C. Jones. 2009. C/EBP-alpha cooperates with bTIF to activate the bovine herpesvirus 1 immediate early transcription unit 1 promoter. J. Neurovirology 15:123-130.
- Workman, A., S. Perez, A. Doster, and C. Jones. 2009. Dexamethasone treatment of calves latently infected with bovine herpesvirus 1 (BHV-1) leads to activation of the bICP0 early promoter, in part by the cellular transcription factor C/EBP-alpha. J. Virology, 83:8800-8809.
- Jones, C. 2009. Regulation of Innate Immune Responses by Bovine Herpesvirus 1 and Infected Cell Protein 0 (bICP0). Viruses 1:255-275.
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