scholarly journals Detailed Characteristics of Tonsillar Tumors with Extrachromosomal or Integrated Form of Human Papillomavirus

Viruses ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 42
Author(s):  
Barbora Pokrývková ◽  
Martina Saláková ◽  
Jana Šmahelová ◽  
Zuzana Vojtěchová ◽  
Vendula Novosadová ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Binding Sites ◽  
Viral Genome ◽  
Sanger Sequencing ◽  
Gene Methylation ◽  
Viral Oncogenes ◽  
E2 Gene ◽  
Viral Carcinogenesis ◽  
Transformation Mechanisms ◽  
Carcinogenic Process

The human papillomavirus (HPV) integration, the critical step in viral carcinogenesis, most frequently occurs in the E2 gene, which results in its inactivation and in an increase of E6/E7 transcription. However, in a substantial number of tumors, the virus is present in an extrachromosomal form. For those tumors, the transformation mechanisms are not fully elucidated. Here we evaluated the possible mechanism of inactivating the E2 without interruption of the gene, methylation or mutation of the E2 binding sites (E2BSs) in HPV16-positive tonsillar tumors by next-generation and Sanger sequencing. Viral genome status was analyzed by the amplification of papillomavirus oncogene transcripts assay (APOT) and mRNA mapping, and expression of viral oncogenes was performed by qPCR. The methylation of E2BSs was significantly higher in tumors with an integrated, in comparison to extrachromosomal, form of the viral genome. No mutations were detected in the E2BSs. The viral oncogenes were equally expressed in samples with an integrated and extrachromosomal form of the virus. Only the nucleotide variants were identified in the E2 gene. No proposed mechanism of E2 inactivation was confirmed in tonsillar tumors with an extrachromosomal form of the HPV genome. The expression of E6/E7 genes seems to be sufficient to initiate and maintain the carcinogenic process

scholarly journals Multiple ASF/SF2 Sites in the Human Papillomavirus Type 16 (HPV-16) E4-Coding Region Promote Splicing to the Most Commonly Used 3′-Splice Site on the HPV-16 Genome

2010 ◽  
Vol 84 (16) ◽  
pp. 8219-8230 ◽  
Author(s):  
Monika Somberg ◽  
Stefan Schwartz
Keyword(s):  
Cervical Cancer ◽  
Human Papillomavirus ◽  
Splice Site ◽  
Binding Sites ◽  
Mrna Levels ◽  
Coding Region ◽  
Cervical Lesions ◽  
Hpv 16 ◽  
Human Papillomavirus Type 16 ◽  
E6 And E7

ABSTRACT Our results presented here demonstrate that the most abundant human papillomavirus type 16 (HPV-16) mRNAs expressing the viral oncogenes E6 and E7 are regulated by cellular ASF/SF2, itself defined as a proto-oncogene and overexpressed in cervical cancer cells. We show that the most frequently used 3′-splice site on the HPV-16 genome, site SA3358, which is used to produce primarily E4, E6, and E7 mRNAs, is regulated by ASF/SF2. Splice site SA3358 is immediately followed by 15 potential binding sites for the splicing factor ASF/SF2. Recombinant ASF/SF2 binds to the cluster of ASF/SF2 sites. Mutational inactivation of all 15 sites abolished splicing to SA3358 and redirected splicing to the downstream-located, late 3′-splice site SA5639. Overexpression of a mutant ASF/SF2 protein that lacks the RS domain, also totally inhibited the usage of SA3358 and redirected splicing to the late 3′-splice site SA5639. The 15 ASF/SF2 binding sites could be replaced by an ASF/SF2-dependent, HIV-1-derived splicing enhancer named GAR. This enhancer was also inhibited by the mutant ASF/SF2 protein that lacks the RS domain. Finally, silencer RNA (siRNA)-mediated knockdown of ASF/SF2 caused a reduction in spliced HPV-16 mRNA levels. Taken together, our results demonstrate that the major HPV-16 3′-splice site SA3358 is dependent on ASF/SF2. SA3358 is used by the most abundantly expressed HPV-16 mRNAs, including those encoding E6 and E7. High levels of ASF/SF2 may therefore be a requirement for progression to cervical cancer. This is supported by our earlier findings that ASF/SF2 is overexpressed in high-grade cervical lesions and cervical cancer.

scholarly journals The SMC5/6 Complex Represses the Replicative Program of High-Risk Human Papillomavirus Type 31

Pathogens ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 786
Author(s):  
Ryan T. Gibson ◽  
Elliot J. Androphy
Keyword(s):  
Human Papillomavirus ◽  
High Risk ◽  
Viral Replication ◽  
Chromatin Immunoprecipitation ◽  
Binding Sites ◽  
Viral Infections ◽  
Hpv Infection ◽  
Regulatory Proteins ◽  
Transactivation Domain ◽  
Structural Maintenance Of Chromosomes

The multi-subunit structural maintenance of chromosomes (SMC) 5/6 complex includes SMC6 and non-SMC element (NSE)3. SMC5/6 is essential for homologous recombination DNA repair and functions as an antiviral factor during hepatitis B (HBV) and herpes simplex-1 (HSV-1) viral infections. Intriguingly, SMC5/6 has been found to associate with high-risk human papillomavirus (HPV) E2 regulatory proteins, but the functions of this interaction and its role during HPV infection remain unclear. Here, we further characterize SMC5/6 interactions with HPV-31 E2 and its role in the HPV life cycle. Co-immunoprecipitation (co-IP) revealed that SMC6 interactions with HPV-31 E2 require the E2 transactivation domain, implying that SMC5/6 interacts with full-length E2. Using chromatin immunoprecipitation, we found that SMC6 is present on HPV-31 episomes at E2 binding sites. The depletion of SMC6 and NSE3 increased viral replication and transcription in keratinocytes maintaining episomal HPV-31, indicating that SMC5/6 restricts the viral replicative program. SMC6 interactions with E2 were reduced in the presence of HPV-31 E1, suggesting that SMC6 and E1 compete for E2 binding. Our findings demonstrate SMC5/6 functions as a repressor of the viral replicative program and this may involve inhibiting the initiation of viral replication.

scholarly journals Neutralization of Human Papillomavirus with Monoclonal Antibodies Reveals Different Mechanisms of Inhibition

2007 ◽  
Vol 81 (16) ◽  
pp. 8784-8792 ◽  
Author(s):  
Patricia M. Day ◽  
Cynthia D. Thompson ◽  
Christopher B. Buck ◽  
Yuk-Ying S. Pang ◽  
Douglas R. Lowy ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Monoclonal Antibodies ◽  
Human Papillomavirus ◽  
Cell Surface ◽  
Binding Sites ◽  
Neutralizing Antibodies ◽  
Hpv Infection ◽  
Heparan Sulfate Proteoglycans ◽  
Hacat Cells ◽  
Block Association

ABSTRACT The mechanisms of human papillomavirus (HPV) neutralization by antibodies are incompletely understood. We have used HPV16 pseudovirus infection of HaCaT cells to analyze how several neutralizing monoclonal antibodies (MAbs) generated against HPV16 L1 interfere with the process of keratinocyte infection. HPV16 capsids normally bind to both the cell surface and extracellular matrix (ECM) of HaCaT cells. Surprisingly, two strongly neutralizing MAbs, V5 and E70, did not prevent attachment of capsids to the cell surface. However, they did block association with the ECM and prevented internalization of cell surface-bound capsids. In contrast, MAb U4 prevented binding to the cell surface but not to the ECM. The epitope recognized by U4 was inaccessible when virions were bound to the cell surface but became accessible after endocytosis, presumably coinciding with receptor detachment. Treatment of capsids with heparin, which is known to interfere with binding to cell surface heparan sulfate proteoglycans (HSPGs), also resulted in HPV16 localization to the ECM. These results suggest that the U4 epitope on the intercapsomeric C-terminal arm is likely to encompass the critical HSPG interaction residues for HPV16, while the V5 and E70 epitopes at the apex of the capsomer overlap the ECM-binding sites. We conclude that neutralizing antibodies can inhibit HPV infection by multiple distinct mechanisms, and understanding these mechanisms can add insight to the HPV entry processes.

scholarly journals Identification of a Dynein Interacting Domain in the Papillomavirus Minor Capsid Protein L2

2006 ◽  
Vol 80 (13) ◽  
pp. 6691-6696 ◽  
Author(s):  
Luise Florin ◽  
Katrin A. Becker ◽  
Carsten Lambert ◽  
Thorsten Nowak ◽  
Cornelia Sapp ◽  
...  
Keyword(s):  
Amino Acids ◽  
Human Papillomavirus ◽  
Capsid Protein ◽  
Viral Genome ◽  
Promyelocytic Leukemia ◽  
Protein Bodies ◽  
Viral Dna ◽  
Microtubule Network ◽  
Promyelocytic Leukemia Protein ◽  
Minor Capsid Protein

ABSTRACT Papillomaviruses enter cells via endocytosis (H. C. Selinka et al., Virology 299:279-287, 2002). After egress from endosomes, the minor capsid protein L2 accompanies the viral DNA to the nucleus and subsequently to the subnuclear promyelocytic leukemia protein bodies (P. M. Day et al., Proc. Natl. Acad. Sci. USA 101:14252-14257, 2004), suggesting that this protein may be involved in the intracytoplasmic transport of the viral genome. We now demonstrate that the L2 protein is able to interact with the microtubule network via the motor protein dynein. L2 protein was found attached to microtubules after uncoating of incoming human papillomavirus pseudovirions. Based on immunofluorescence and coimmunoprecipitation analyses, the L2 region interacting with dynein is mapped to the C-terminal 40 amino acids. Mutations within this region abrogating the L2/dynein interaction strongly reduce the infectivity of pseudoviruses, indicating that this interaction mediates the minus-end-directed transport of the viral genome along microtubules towards the nucleus.

A four-gene methylation marker panel as triage test in high-risk human papillomavirus positive patients

2012 ◽  
Vol 130 (8) ◽  
pp. 1861-1869 ◽  
Author(s):  
J.J.H. Eijsink ◽  
Á. Lendvai ◽  
V. Deregowski ◽  
H.G. Klip ◽  
G. Verpooten ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
High Risk ◽  
Gene Methylation ◽  
Marker Panel ◽  
Methylation Marker ◽  
Triage Test
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