scholarly journals Bovine Herpesvirus 1 UL3.5 Interacts with Bovine Herpesvirus 1 α-Transinducing Factor

2000 ◽  
Vol 74 (6) ◽  
pp. 2876-2884 ◽  
Author(s):  
Ngan Lam ◽  
Geoffrey J. Letchworth

ABSTRACT The bovine herpesvirus 1 (BHV-1) UL3.5 gene encodes a 126-amino-acid tegument protein. Homologs of UL3.5 are present in some alphaherpesviruses and have 20 to 30% overall amino acid homology that is concentrated in the N-terminal 50 amino acids. Mutant pseudorabies virus lacking UL3.5 is deficient in viral egress but can be complemented by BHV-1 UL3.5 (W. Fuchs, H. Granzow, and T. C. Mettenleiter, J. Virol. 71:8886–8892, 1997). The function of BHV-1 UL3.5 in BHV-1 replication is not known. To get a better understanding of its function, we sought to identify the proteins that interact with the BHV-1 UL3.5 protein. By using an in vitro pull-down assay and matrix-assisted laser desorption ionization mass spectrometry analysis, we identified BHV-1 α-transinducing factor (αBTIF) as a BHV-1 UL3.5-interacting protein. The interaction was verified by coimmunoprecipitation from virus-infected cells using an antibody to either protein, by indirect immunofluorescence colocalization in both virus-infected and transfected cells, and by the binding of in vitro-translated proteins. In virus-infected cells, UL3.5 and αBTIF colocalized in a Golgi-like subcellular compartment late in infection. In transfected cells, they colocalized in the nucleus. Deletion of 20 amino acids from the N terminus of UL3.5, but not 40 amino acids from the C terminus, abolished the UL3.5-αBTIF interaction both in vitro and in vivo. The interaction between UL3.5 and αBTIF may be important for BHV-1 maturation and regulation of αBTIF transactivation activity.

2009 ◽  
Vol 90 (12) ◽  
pp. 2829-2839 ◽  
Author(s):  
Shaunivan L. Labiuk ◽  
Lorne A. Babiuk ◽  
Sylvia van Drunen Littel-van den Hurk

The UL47 gene product, VP8, is one of the major tegument proteins of bovine herpesvirus 1 (BoHV-1) and is subject to phosphorylation. Analysis of protein bands co-immunoprecipitated with VP8 from BoHV-1-infected cells by mass spectroscopy suggested that VP8 interacts with two protein kinases: cellular CK2 and viral US3. CK2 is a highly conserved cellular protein, expressed ubiquitously and known to phosphorylate numerous proteins. The US3 gene product is one of the viral kinases produced by BoHV-1 during infection. Interactions of CK2 and US3 with VP8 were confirmed outside the context of infection when FLAG–VP8 was expressed alone or co-expressed with US3–haemagglutinin tag in Cos-7 cells. Furthermore, VP8 and US3 were found to co-localize in the nucleus during viral infection. To explore the significance of these interactions, an in vitro kinase assay was performed, which demonstrated that VP8 is heavily phosphorylated by CK2. In the presence of the highly specific CK2 kinase inhibitor 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole (DMAT), phosphorylation of VP8 was significantly reduced. Phosphorylation of VP8 was also inhibited by the presence of kenpaullone, a less specific CK2 inhibitor, but not by protein kinase CK1 or protein kinase C inhibitors. When VP8 and US3 were both included in the kinase assay in the presence of DMAT, phosphorylation of VP8 was again observed. Autophosphorylation of US3 was also detected and was not inhibited by DMAT. Based on these results, it is proposed that VP8 interacts with cellular CK2 and viral US3 in BoHV-1-infected cells, and is in turn subject to kinase activities associated with both of these proteins.


2005 ◽  
Vol 79 (18) ◽  
pp. 11864-11872 ◽  
Author(s):  
Chunfu Zheng ◽  
Robert Brownlie ◽  
Lorne A. Babiuk ◽  
Sylvia van Drunen Littel-van den Hurk

ABSTRACT The bovine herpesvirus 1 (BHV-1) tegument protein VP22 is predominantly localized in the nucleus after viral infection. To analyze subcellular localization in the absence of other viral proteins, a plasmid expressing BHV-1 VP22 fused to enhanced yellow fluorescent protein (EYFP) was constructed. The transient expression of VP22 fused to EYFP in COS-7 cells confirmed the predominant nuclear localization of VP22. Analysis of the amino acid sequence of VP22 revealed that it does not have a classical nuclear localization signal (NLS). However, by constructing a series of deletion derivatives, we mapped the nuclear targeting domain of BHV-1 VP22 to amino acids (aa) 121 to 139. Furthermore, a 4-aa motif, 130PRPR133, was able to direct EYFP and an EYFP dimer (dEYFP) or trimer (tEYFP) predominantly into the nucleus, whereas a deletion or mutation of this arginine-rich motif abrogated the nuclear localization property of VP22. Thus, 130PRPR133 is a functional nonclassical NLS. Since we observed that the C-terminal 68 aa of VP22 mediated the cytoplasmic localization of EYFP, an analysis was performed on these C-terminal amino acid sequences, and a leucine-rich motif, 204LDRMLKSAAIRIL216, was detected. Replacement of the leucines in this putative nuclear export signal (NES) with neutral amino acids resulted in an exclusive nuclear localization of VP22. Furthermore, this motif was able to localize EYFP and dEYFP in the cytoplasm, and the nuclear export function of this NES could be blocked by leptomycin B. This demonstrates that this leucine-rich motif is a functional NES. These data represent the first identification of a functional NLS and NES in a herpesvirus VP22 homologue.


2016 ◽  
Vol 90 (10) ◽  
pp. 4889-4904 ◽  
Author(s):  
Sharmin Afroz ◽  
Robert Brownlie ◽  
Michel Fodje ◽  
Sylvia van Drunen Littel-van den Hurk

ABSTRACTTheUL47gene product, VP8, is the most abundant tegument protein of bovine herpesvirus 1 (BoHV-1). Previously, we demonstrated that aUL47-deleted BoHV-1 mutant (BoHV1-ΔUL47) exhibits 100-fold-reduced virulencein vitroand is avirulentin vivo. In this study, we demonstrated that VP8 expression or BoHV-1 infection inhibits interferon beta (IFN-β) signaling by using an IFN-α/β-responsive plasmid in a luciferase assay. As transducer and activator of transcription (STAT) is an essential component in the IFN-signaling pathways, the effect of VP8 on STAT was investigated. An interaction between VP8 and STAT1 was established by coimmunoprecipitation assays in both VP8-transfected and BoHV-1-infected cells. Two domains of VP8, amino acids 259 to 482 and 632 to 686, were found to be responsible for its interaction with STAT1. The expression of VP8 did not induce STAT1 ubiquitination or degradation. Moreover, VP8 did not reduce STAT1 tyrosine phosphorylation to downregulate IFN-β signaling. However, the expression of VP8 or a version of VP8 (amino acids 219 to 741) that contains the STAT1-interacting domains but not the nuclear localization signal prevented nuclear accumulation of STAT1. Inhibition of nuclear accumulation of STAT1 also occurred during BoHV-1 infection, while nuclear translocation of STAT1 was observed in BoHV1-ΔUL47-infected cells. During BoHV-1 infection, VP8 was detected in the cytoplasm at 2 h postinfection without anyde novoprotein synthesis, at which time STAT1 was already retained in the cytoplasm. These results suggest that viral VP8 downregulates IFN-β signaling early during infection, thus playing a role in overcoming the antiviral response of BoHV-1-infected cells.IMPORTANCESince VP8 is the most abundant protein in BoHV-1 virions and thus may be released in large amounts into the host cell immediately upon infection, we proposed that it might have a function in the establishment of conditions suitable for viral replication. Indeed, while nonessentialin vitro, it is critical for BoHV-1 replicationin vivo. In this study, we determined that VP8 plays a role in downregulation of the antiviral host response by inhibiting IFN-β signaling. VP8 interacted with and prevented nuclear accumulation of STAT1 at 2 h postinfection in the absence ofde novoviral protein synthesis. Two domains of VP8, amino acids 259 to 482 and 632 to 686, were found to be responsible for this interaction. These results provide a new functional role for VP8 in BoHV-1 infection and a potential explanation for the lack of viral replication of theUL47deletion mutant in cattle.


Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1854
Author(s):  
Soumya Sucharita ◽  
Kuan Zhang ◽  
Sylvia van Drunen Littel-van den Hurk

Bovine herpesvirus-1 (BoHV-1) is a major cause of rhinotracheitis and vulvovaginitis in cattle. VP8, the major tegument protein of BoHV-1, is essential for viral replication in the host. VP8 is phosphorylated by the viral kinase US3, mediating its translocation to the cytoplasm. VP8 remains nuclear when not phosphorylated. Interestingly, VP8 has a significant presence in mature BoHV-1YmVP8, in which the VP8 phosphorylation sites are mutated. This suggests that VP8 might be packaged during primary envelopment of BoHV-1. This was investigated by mass spectrometry and Western blotting, which showed VP8, as well as VP22, to be constituents of the primary enveloped virions. VP8 and VP22 were shown to interact via co-immunoprecipitation experiments, in both BoHV-1-infected and VP8-transfected cells. VP8 and VP22 also co-localised with one another and with nuclear lamin-associated protein 2 in BoHV-1-infected cells, suggesting an interaction between VP8 and VP22 in the perinuclear region. In cells infected with VP22-deleted BoHV-1 (BoHV-1ΔUL49), VP8 was absent from the primary enveloped virions, implying that VP22 might be critical for the early packaging of VP8. In conclusion, a novel VP22-dependent mechanism for packaging of VP8 was identified, which may be responsible for a significant amount of VP8 in the viral particle.


2002 ◽  
Vol 76 (14) ◽  
pp. 7255-7262 ◽  
Author(s):  
Wanda M. Martinez ◽  
Patricia G. Spear

ABSTRACT The entry of herpes simplex virus (HSV) into cells requires the interaction of viral glycoprotein D (gD) with a cellular gD receptor to trigger the fusion of viral and cellular membranes. Nectin-1, a member of the immunoglobulin superfamily, can serve as a gD receptor for HSV types 1 and 2 (HSV-1 and HSV-2, respectively) as well as for the animal herpesviruses porcine pseudorabies virus (PRV) and bovine herpesvirus 1 (BHV-1). The HSV-1 gD binding domain of nectin-1 is hypothesized to overlap amino acids 64 to 104 of the N-terminal variable domain-like immunoglobulin domain. Moreover, the HSV-1 and PRV gDs compete for binding to nectin-1. Here we report that two amino acids within this region, at positions 77 and 85, are critical for HSV-1 and HSV-2 entry but not for the entry of PRV or BHV-1. Replacement of either amino acid 77 or amino acid 85 reduced HSV-1 and HSV-2 gD binding but had a lesser effect on HSV entry activity, suggesting that weak interactions between gD and nectin-1 are sufficient to trigger the mechanism of HSV entry. Substitution of both amino acid 77 and amino acid 85 in nectin-1 significantly impaired entry activity for HSV-1 and HSV-2 and eliminated binding to soluble forms of HSV-1 and HSV-2 gDs but did not impair the entry of PRV and BHV-1. Thus, amino acids 77 and 85 of nectin-1 form part of the interface with HSV gD or influence the conformation of that interface. Moreover, the binding sites for HSV and PRV or BHV-1 gDs on nectin-1 may overlap but are not identical.


2006 ◽  
Vol 18 (2) ◽  
pp. 213 ◽  
Author(s):  
M. Givens ◽  
M. Marley ◽  
P. Galik ◽  
K. Riddell ◽  
D. Stringfellow

Lactoferrin is an iron-binding glycoprotein found in milk, saliva, tears, and other exocrine secretions. It is known to have in vitro antiviral effects against human, feline, and canine herpesviruses. In addition, lactoferrin is known to be safe in cell culture. Bovine herpesvirus-1 (BHV-1) is a likely contaminant of in vitro embryo production. Further, trypsin treatment is not completely effective in removing the virus from these embryos. We hypothesized that a nontoxic concentration of lactoferrin might prevent replication of BHV-1 within in vitro embryo production systems. Thus, the specific objectives of this research were to determine if lactoferrin from bovine milk would inhibit BHV-1 in cell culture and to determine if in vitro-produced embryos could develop normally when cultured in lactoferrin. Two-fold dilutions of lactoferrin (from 10 to 0.625 mg/mL) were added to Madin Darby bovine kidney cells, followed in 15 min by the addition 104 PFU/mL of BHV-1 (Colorado strain). Samples of cell lysate were taken at Day 2 and virus was quantified by plaque assay. The percent of virus inhibited by the antiviral agent at each concentration was determined by comparison to equivalent samples from temporal control cultures in which no compound was added before or after inoculation (Percentage of virus inhibited = [Quantity of virus in the control sample - Quantity of virus in the compound sample]/Quantity of virus in the control sample � 100). Next, the effect of lactoferrin was determined on in vitro-produced embryos. Cumulus oocyte complexes were received from an abattoir, matured in transit, placed in fertilization drops for 6 h, and then placed in culture drops containing lactoferrin (10, 5, and 2.5 mg/mL). At Day 3.5, embryos > 4 cell stage were placed into fresh culture drops containing lactoferrin. On Day 7.5, blastocyst development was noted and the developed embryos were stained to count viable cells. Blastocyst development rate and nucleated cell count of the treated embryos were compared to those of the controls using Chi square test, and ANOVA and Tukey-Kramer HSD, respectively. Lactoferrin (10 mg/mL) inhibited 2 to 5 logs of virus. At concentrations of 5 and 2.5 mg/mL, 1 to 3 logs of virus were inhibited, and concentrations of 1.25 and 0.625 mg/mL inhibited 0 to 2 logs of virus. Lactoferrin did not affect the nucleated cell count of the treated embryos. In addition, unlike 10 and 5 mg/mL, 2.5 mg/mL of lactoferrin did not affect blastocyst development. These preliminary results indicate that lactoferrin from bovine milk can significantly inhibit BHV-1 in cell culture. Furthermore, supplementation of in vitro culture with 2.5 mg/mL of lactoferrin does not affect blastocyst development or cell count of in vitro-produced embryos.


2009 ◽  
Vol 21 (1) ◽  
pp. 173 ◽  
Author(s):  
A. Bielanski ◽  
A. Lalonde ◽  
J. Algire

Bovine herpesvirus-1 (BHV-1) causes a variety of economically important respiratory and reproductive problems, the latter including vulvovaginitis, endometritis and infertility. For that reason, several countries have eradicated the disease and others have schemes in progress to achieve freedom. Although there is a considerable amount of information about the risk of BHV-1 transmission through contaminated semen used for artificial insemination, there is no available evidence to indicate whether the resulting embryos, when used for embryo transter (ET), can lead to the transmission of BHV-1 to recipients and offspring. For this experiment, bull semen contaminated in vitro with BHV-1 at 102 TCID50 mL–1 (Colorado strain) and then cryopreserved was used for insemination (2 times at estrus) of BHV-1 seronegative, superovulated heifers (N = 18). Embryos were collected postmortem 7 days post-insemination and were washed according to the IETS recommendations (however without trypsin treatment) or left unwashed. On 4 occasions, washed embryos were transferred to BHV-1 seronegative recipients. The remaining embryos and other samples collected from the reproductive tract were tested for BHV-1 presence using the standard virus isolation test. In total, out of 144 unfertilized oocytes and embryos collected, 9 were ET quality. Most of the embryos were degenerated (N = 79) or unfertilized (N = 56). The 4 heifers, which each received a single morula-stage embryo, maintained seronegative status, but did not become pregnant. BHV-1 was detected in 43% (23/53) unwashed and 0% (0/57) of washed embryos, 78% (14/18) of follicular fluid samples, 89% (16/18) of oviductal epithelial cells, 78% (14/18) of endometrium, and 89% (16/18) of corpora lutea tissues. Results herein suggest that BHV-1 can be transmitted by infected semen to embryo donors. The resulting unwashed embryos may remain infectious. However, whether BHV-1 uninfected offspring can be produced by ET of BHV-1 contaminated embryos that are washed according to the IETS guidelines, remains to be determined.


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