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 Equine Hoof Canker: Bovine Papillomavirus Infection Is Not Associated With Impaired Keratinocyte Differentiation

2020 ◽  
Vol 57 (4) ◽  
pp. 525-534
Author(s):  
Veronika Apprich ◽  
Theresia Licka ◽  
Sabrina Freiler ◽  
Cordula Gabriel
Keyword(s):  
Adhesion Molecules ◽  
Intermediate Filaments ◽  
Expression Patterns ◽  
Keratinocyte Differentiation ◽  
Bovine Papillomavirus ◽  
Tissue Samples ◽  
Altered Expression ◽  
Morphological Alterations ◽  
Papillomavirus Infection ◽  
Equine Hoof

Impaired keratinocyte differentiation has recently been suggested as a key event in equine hoof canker development. Koilocytotic appearance of keratinocytes, one of the most characteristic morphological alterations in hoof canker tissue, is also a common marker for papillomavirus (PV) infection, and bovine PV-1 and/or -2 (BPV-1/2) has previously been detected in equine canker patients. Therefore, the present study aimed to correlate the frequency and severity of koilocytotic keratinocytes with BPV detection in hoof canker samples. Hoof tissue of 5/18 canker-affected horses and 2/6 control horses tested positive for BPV-1/2 DNA using polymerase chain reaction. Thus, no association between the presence of BPV-1/2 papillomaviral DNA and koilocytotic appearance was found. Proteins associated with but not specific for PV infection were also investigated. Using immunohistochemistry, specific adhesion molecules (E-cadherin and β-catenin) and intermediate filaments (keratins 6 and 14) important for intact epidermal barrier function and keratinocyte differentiation were documented in control samples ( n = 6) and in hoof canker tissue samples ( n = 19). Altered expression patterns of intermediate filaments and adhesion molecules were demonstrated in canker tissue, confirming the importance of incomplete keratinocyte differentiation, as well as the crucial role of keratinocyte differentiation in hoof canker.

scholarly journals Opposing effects of bovine papillomavirus type 1 E6 and E7 genes on Fas-mediated apoptosis

Oncogene ◽  
2005 ◽  
Vol 24 (24) ◽  
pp. 3942-3953 ◽  
Author(s):  
Yun Liu ◽  
Zhiguo Liu ◽  
Hua Gao ◽  
You Zhou ◽  
Elliot J Androphy ◽  
...  
Keyword(s):  
Bovine Papillomavirus ◽  
E6 And E7 ◽  
Opposing Effects

scholarly journals Mutagenic Potential ofBos taurusPapillomavirus Type 1 E6 Recombinant Protein: First Description

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Rodrigo Pinheiro Araldi ◽  
Jacqueline Mazzuchelli-de-Souza ◽  
Diego Grando Modolo ◽  
Edislane Barreiros de Souza ◽  
Thatiana Corrêa de Melo ◽  
...  
Keyword(s):  
Bos Taurus ◽  
Micronucleus Assay ◽  
Positive Control ◽  
Bovine Papillomavirus ◽  
Mutagenic Potential ◽  
E6 Oncoprotein ◽  
Per Se ◽  
E6 And E7 ◽  
Negative Controls

Bovine papillomavirus (BPV) is considered a useful model to study HPV oncogenic process. BPV interacts with the host chromatin, resulting in DNA damage, which is attributed to E5, E6, and E7 viral oncoproteins activity. However, the oncogenic mechanisms of BPV E6 oncoproteinper seremain unknown. This study aimed to evaluate the mutagenic potential ofBos tauruspapillomavirus type 1 (BPV-1) E6 recombinant oncoprotein by the cytokinesis-block micronucleus assay (CBMNA) and comet assay (CA). Peripheral blood samples of five calves were collected. Samples were subjected to molecular diagnosis, which did not reveal presence of BPV sequences. Samples were treated with 1 μg/mL of BPV-1 E6 oncoprotein and 50 μg/mL of cyclophosphamide (positive control). Negative controls were not submitted to any treatment. The samples were submitted to the CBMNA and CA. The results showed that BPV E6 oncoprotein induces clastogenesisper se, which is indicative of genomic instability. These results allowed better understanding the mechanism of cancer promotion associated with the BPV E6 oncoprotein and revealed that this oncoprotein can induce carcinogenesisper se. E6 recombinant oncoprotein has been suggested as a possible vaccine candidate. Results pointed out that BPV E6 recombinant oncoprotein modifications are required to use it as vaccine.

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 Exonic Splicing Enhancer-Dependent Selection of the Bovine Papillomavirus Type 1 Nucleotide 3225 3′ Splice Site Can Be Rescued in a Cell Lacking Splicing Factor ASF/SF2 through Activation of the Phosphatidylinositol 3-Kinase/Akt Pathway

2003 ◽  
Vol 77 (3) ◽  
pp. 2105-2115 ◽  
Author(s):  
Xuefeng Liu ◽  
Akila Mayeda ◽  
Mingfang Tao ◽  
Zhi-Ming Zheng
Keyword(s):  
Splice Site ◽  
Rna Splicing ◽  
Viral Rna ◽  
Splicing Factor ◽  
Rna Expression ◽  
Bovine Papillomavirus ◽  
Phosphatidylinositol 3 Kinase ◽  
Selection Of ◽  
Phosphatidylinositol 3

ABSTRACT Bovine papillomavirus type 1 (BPV-1) late pre-mRNAs are spliced in keratinocytes in a differentiation-specific manner: the late leader 5′ splice site alternatively splices to a proximal 3′ splice site (at nucleotide 3225) to express L2 or to a distal 3′ splice site (at nucleotide 3605) to express L1. Two exonic splicing enhancers, each containing two ASF/SF2 (alternative splicing factor/splicing factor 2) binding sites, are located between the two 3′ splice sites and have been identified as regulating alternative 3′ splice site usage. The present report demonstrates for the first time that ASF/SF2 is required under physiological conditions for the expression of BPV-1 late RNAs and for selection of the proximal 3′ splice site for BPV-1 RNA splicing in DT40-ASF cells, a genetically engineered chicken B-cell line that expresses only human ASF/SF2 controlled by a tetracycline-repressible promoter. Depletion of ASF/SF2 from the cells by tetracycline greatly decreased viral RNA expression and RNA splicing at the proximal 3′ splice site while increasing use of the distal 3′ splice site in the remaining viral RNAs. Activation of cells lacking ASF/SF2 through anti-immunoglobulin M-B-cell receptor cross-linking rescued viral RNA expression and splicing at the proximal 3′ splice site and enhanced Akt phosphorylation and expression of the phosphorylated serine/arginine-rich (SR) proteins SRp30s (especially SC35) and SRp40. Treatment with wortmannin, a specific phosphatidylinositol 3-kinase/Akt kinase inhibitor, completely blocked the activation-induced activities. ASF/SF2 thus plays an important role in viral RNA expression and splicing at the proximal 3′ splice site, but activation-rescued viral RNA expression and splicing in ASF/SF2-depleted cells is mediated through the phosphatidylinositol 3-kinase/Akt pathway and is associated with the enhanced expression of other SR proteins.

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