scholarly journals Inoculation of young horses with bovine papillomavirus type 1 virions leads to early infection of PBMCs prior to pseudo-sarcoid formation

2011 ◽  
Vol 92 (10) ◽  
pp. 2437-2445 ◽  
Author(s):  
Bettina Hartl ◽  
Edmund K. Hainisch ◽  
Saeed Shafti-Keramat ◽  
Reinhard Kirnbauer ◽  
Annunziata Corteggio ◽  
...  
Keyword(s):  
Neutralization Assay ◽  
Bovine Papillomavirus ◽  
Serum Antibodies ◽  
Intact Skin ◽  
Papillomavirus Infection ◽  
E5 Protein ◽  
E5 Oncoprotein ◽  
Young Horses ◽  
And Control

Bovine papillomavirus types 1 and 2 (BPV-1 and BPV-2) are known to induce common equine skin tumours, termed sarcoids. Recently, it was demonstrated that vaccination with BPV-1 virus-like particles (VLPs) is safe and highly immunogenic in horses. To establish a BPV-1 challenge model for evaluation of the protective potential of BPV-1 VLPs, four foals were injected intradermally with infectious BPV-1 virions and with viral genome-based and control inocula, and monitored daily for tumour development. Blood was taken before inoculation and at weekly intervals. BPV-1-specific serum antibodies were detected by a pseudo-virion neutralization assay. Total nucleic acids extracted from tumours, intact skin and PBMCs were tested for the presence of BPV-1 DNA and mRNA using PCR and RT-PCR, respectively. Intralesional E5 oncoprotein expression was determined by immunofluorescence. Pseudo-sarcoids developed exclusively at sites inoculated with virions. Tumours became palpable 11–32 days after virion challenge, reached a size of ≤20 mm in diameter and then resolved in ≤6 months. No neutralizing anti-BPV-1 serum antibodies were detectable pre- or post-challenge. BPV-1 DNA was present in lesions but not in intact skin. In PBMCs, viral DNA was already detectable before lesions were first palpable, in concentrations correlating directly with tumour growth kinetics. PBMCs from two of two foals also harboured E5 mRNA. Immunofluorescence revealed the presence of the E5 protein in tumour fibroblasts, but not in the apparently normal epidermis overlying the lesions. Together with previous findings obtained in horses and cows, these data suggest that papillomavirus infection may include a viraemic phase.

scholarly journals Two transmembrane dimers of the bovine papillomavirus E5 oncoprotein clamp the PDGF β receptor in an active dimeric conformation

2017 ◽  
Vol 114 (35) ◽  
pp. E7262-E7271 ◽  
Author(s):  
Alexander G. Karabadzhak ◽  
Lisa M. Petti ◽  
Francisco N. Barrera ◽  
Anne P. B. Edwards ◽  
Andrés Moya-Rodríguez ◽  
...  
Keyword(s):  
Transmembrane Domain ◽  
Transmembrane Protein ◽  
Receptor Activation ◽  
Bovine Papillomavirus ◽  
Detailed Model ◽  
E5 Protein ◽  
Membrane Modeling ◽  
E5 Oncoprotein ◽  
Β Receptor ◽  
Dynamics Simulations

The dimeric 44-residue E5 protein of bovine papillomavirus is the smallest known naturally occurring oncoprotein. This transmembrane protein binds to the transmembrane domain (TMD) of the platelet-derived growth factor β receptor (PDGFβR), causing dimerization and activation of the receptor. Here, we use Rosetta membrane modeling and all-atom molecular dynamics simulations in a membrane environment to develop a chemically detailed model of the E5 protein/PDGFβR complex. In this model, an active dimer of the PDGFβR TMD is sandwiched between two dimers of the E5 protein. Biochemical experiments showed that the major PDGFβR TMD complex in mouse cells contains two E5 dimers and that binding the PDGFβR TMD to the E5 protein is necessary and sufficient to recruit both E5 dimers into the complex. These results demonstrate how E5 binding induces receptor dimerization and define a molecular mechanism of receptor activation based on specific interactions between TMDs.

scholarly journals Control of the Papillomavirus Early-to-Late Switch by Differentially Expressed SRp20

2008 ◽  
Vol 83 (1) ◽  
pp. 167-180 ◽  
Author(s):  
Rong Jia ◽  
Xuefeng Liu ◽  
Mingfang Tao ◽  
Michael Kruhlak ◽  
Ming Guo ◽  
...  
Keyword(s):  
Keratinocyte Differentiation ◽  
Bovine Papillomavirus ◽  
Cellular Transcription Factor ◽  
Monolayer Cultures ◽  
Papillomavirus Infection ◽  
Alternative Mrna Splicing ◽  
E6 And E7 ◽  
Cellular Transcription ◽  
Selection Of

ABSTRACT The viral early-to-late switch of papillomavirus infection is tightly linked to keratinocyte differentiation and is mediated in part by alternative mRNA splicing. Here, we report that SRp20, a cellular splicing factor, controls the early-to-late switch via interactions with A/C-rich RNA elements. An A/C-rich SE4 element regulates the selection of a bovine papillomavirus type 1 (BPV-1) late-specific splice site, and binding of SRp20 to SE4 suppresses this selection. Expression of late BPV-1 L1 or human papillomavirus (HPV) L1, the major capsid protein, inversely correlates with SRp20 levels in the terminally differentiated keratinocytes. In HPV type 16, a similar SRp20-interacting element also controls the viral early-to-late switch. Keratinocytes in raft cultures, which support L1 expression, make considerably less SRp20 than keratinocytes in monolayer cultures, which do not support L1 expression. Conversely, abundant SRp20 in cancer cells or undifferentiated keratinocytes is important for the expression of the viral early E6 and E7 by promoting the expression of cellular transcription factor SP1 for transactivation of viral early promoters.

scholarly journals Cooperative Transformation and Coexpression of Bovine Papillomavirus Type 1 E5 and E7 Proteins

2001 ◽  
Vol 75 (1) ◽  
pp. 513-521 ◽  
Author(s):  
Joanna Bohl ◽  
Bruce Hull ◽  
Scott B. Vande Pol
Keyword(s):  
Epithelial Cells ◽  
Cellular Response ◽  
Ectopic Expression ◽  
Granular Cell ◽  
Bovine Papillomavirus ◽  
Basal Cells ◽  
Cultured Epithelial Cells ◽  
E5 Oncoprotein ◽  
E7 Proteins

ABSTRACT Productively infected bovine fibropapillomas were examined for bovine papillomavirus type 1 (BPV-1) E7 localization. BPV-1 E7 was observed in the cytoplasm of basal and lower spinous epithelial cells, coexpressed in the cytoplasm of basal cells with the E5 oncoprotein. E7 was also observed in nucleoli throughout the basal and spinous layers but not in the granular cell layer. Ectopic expression of E7 in cultured epithelial cells gave rise to localization similar to that seen in productive fibropapillomas, with cytoplasmic and nucleolar expression observed. Consistent with the coexpression of E7 and E5 in basal keratinocytes, BPV-1 E7 cooperated with E5 as well as E6 in an anchorage independence transformation assay. While E5 is expressed in both basal and superficial differentiating keratinocytes, BPV-1 E7 is only observed in basal and lower spinous epithelial cells. Therefore, BPV-1 E7 may serve to modulate the cellular response of basal epithelial cells to E5 expression.

scholarly journals Genetic evidence that acute morphologic transformation, induction of cellular DNA synthesis, and focus formation are mediated by a single activity of the bovine papillomavirus E5 protein.

1989 ◽  
Vol 9 (12) ◽  
pp. 5563-5572 ◽  
Author(s):  
J Settleman ◽  
A Fazeli ◽  
J Malicki ◽  
B H Horwitz ◽  
D DiMaio
Keyword(s):  
Dna Synthesis ◽  
Mutational Analysis ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Serum Starvation ◽  
Bovine Papillomavirus ◽  
Focus Formation ◽  
E5 Protein ◽  
Cellular Dna

The bovine papillomavirus (BPV) type 1 E5 gene encodes a 44-amino-acid protein that can stably transform cultured rodent cells when expressed in the absence of all other viral genes. We have previously constructed a BPV-simian virus 40 recombinant virus (Pava-1) which efficiently expresses the BPV type 1 E5 gene in infected cells (J. Settleman and D. DiMaio, Proc. Natl. Acad. Sci. USA 85:9007-9011, 1988). Within 48 h of Pava-1 infection, the vast majority of mouse C127 cells underwent a dramatic morphologic transformation which was accompanied by cell proliferation. Infection of C127 cells made quiescent by contact inhibition and serum starvation caused a great induction of cellular DNA synthesis. These morphologic and mitogenic responses were proportional to the virus multiplicity of infection. Mutational analysis indicated that the E5 gene is both necessary and sufficient for these activities. Analysis of a variety of E5 missense mutants revealed a strong correlation between their phenotypes in the acute transformation assays following infection and in the stable focus-forming assay following transfection. Most of the defective mutants expressed normal levels of E5 protein following infection, indicating that their defective phenotypes are not due to the synthesis of an unstable protein. The failure to genetically resolve these E5 activities suggests that the ability of the E5 protein to cause acute morphologic transformation and reentry into the cell cycle may be intimately related to its ability to cause stable cell transformation and that these functions are probably mediated by a single biochemical activity of the E5 protein.

Genetic evidence that acute morphologic transformation, induction of cellular DNA synthesis, and focus formation are mediated by a single activity of the bovine papillomavirus E5 protein

1989 ◽  
Vol 9 (12) ◽  
pp. 5563-5572
Author(s):  
J Settleman ◽  
A Fazeli ◽  
J Malicki ◽  
B H Horwitz ◽  
D DiMaio
Keyword(s):  
Dna Synthesis ◽  
Mutational Analysis ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Serum Starvation ◽  
Bovine Papillomavirus ◽  
Focus Formation ◽  
E5 Protein ◽  
Cellular Dna

The bovine papillomavirus (BPV) type 1 E5 gene encodes a 44-amino-acid protein that can stably transform cultured rodent cells when expressed in the absence of all other viral genes. We have previously constructed a BPV-simian virus 40 recombinant virus (Pava-1) which efficiently expresses the BPV type 1 E5 gene in infected cells (J. Settleman and D. DiMaio, Proc. Natl. Acad. Sci. USA 85:9007-9011, 1988). Within 48 h of Pava-1 infection, the vast majority of mouse C127 cells underwent a dramatic morphologic transformation which was accompanied by cell proliferation. Infection of C127 cells made quiescent by contact inhibition and serum starvation caused a great induction of cellular DNA synthesis. These morphologic and mitogenic responses were proportional to the virus multiplicity of infection. Mutational analysis indicated that the E5 gene is both necessary and sufficient for these activities. Analysis of a variety of E5 missense mutants revealed a strong correlation between their phenotypes in the acute transformation assays following infection and in the stable focus-forming assay following transfection. Most of the defective mutants expressed normal levels of E5 protein following infection, indicating that their defective phenotypes are not due to the synthesis of an unstable protein. The failure to genetically resolve these E5 activities suggests that the ability of the E5 protein to cause acute morphologic transformation and reentry into the cell cycle may be intimately related to its ability to cause stable cell transformation and that these functions are probably mediated by a single biochemical activity of the E5 protein.

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