scholarly journals Persistent Human Papillomavirus Infection

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 321
Author(s):  
Ashley N. Della Fera ◽  
Alix Warburton ◽  
Tami L. Coursey ◽  
Simran Khurana ◽  
Alison A. McBride
Keyword(s):  
Human Papillomavirus ◽  
Dna Replication ◽  
Cellular Proliferation ◽  
Basal Cells ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Viral Genomes ◽  
Cellular Environment ◽  
E6 And E7 ◽  
Cellular Replication

Persistent infection with oncogenic human papillomavirus (HPV) types is responsible for ~5% of human cancers. The HPV infectious cycle can sustain long-term infection in stratified epithelia because viral DNA is maintained as low copy number extrachromosomal plasmids in the dividing basal cells of a lesion, while progeny viral genomes are amplified to large numbers in differentiated superficial cells. The viral E1 and E2 proteins initiate viral DNA replication and maintain and partition viral genomes, in concert with the cellular replication machinery. Additionally, the E5, E6, and E7 proteins are required to evade host immune responses and to produce a cellular environment that supports viral DNA replication. An unfortunate consequence of the manipulation of cellular proliferation and differentiation is that cells become at high risk for carcinogenesis.

scholarly journals Nuclear Export of Human Papillomavirus Type 31 E1 Is Regulated by Cdk2 Phosphorylation and Required for Viral Genome Maintenance

2010 ◽  
Vol 84 (22) ◽  
pp. 11747-11760 ◽  
Author(s):  
Amélie Fradet-Turcotte ◽  
Cary Moody ◽  
Laimonis A. Laimins ◽  
Jacques Archambault
Keyword(s):  
Human Papillomavirus ◽  
Dna Replication ◽  
Nuclear Export ◽  
Viral Genome ◽  
Cellular Proliferation ◽  
Nuclear Export Signal ◽  
Nuclear Accumulation ◽  
Genome Maintenance ◽  
Viral Dna ◽  
Viral Dna Replication

ABSTRACT The initiator protein E1 from human papillomavirus (HPV) is a helicase essential for replication of the viral genome. E1 contains three functional domains: a C-terminal enzymatic domain that has ATPase/helicase activity, a central DNA-binding domain that recognizes specific sequences in the origin of replication, and a N-terminal region necessary for viral DNA replication in vivo but dispensable in vitro. This N-terminal portion of E1 contains a conserved nuclear export signal (NES) whose function in the viral life cycle remains unclear. In this study, we provide evidence that nuclear export of HPV31 E1 is inhibited by cyclin E/A-Cdk2 phosphorylation of two serines residues, S92 and S106, located near and within the E1 NES, respectively. Using E1 mutant proteins that are confined to the nucleus, we determined that nuclear export of E1 is not essential for transient viral DNA replication but is important for the long-term maintenance of the HPV episome in undifferentiated keratinocytes. The findings that E1 nuclear export is not required for viral DNA replication but needed for genome maintenance over multiple cell divisions raised the possibility that continuous nuclear accumulation of E1 is detrimental to cellular growth. In support of this possibility, we observed that nuclear accumulation of E1 dramatically reduces cellular proliferation by delaying cell cycle progression in S phase. On the basis of these results, we propose that nuclear export of E1 is required, at least in part, to limit accumulation of this viral helicase in the nucleus in order to prevent its detrimental effect on cellular proliferation.

scholarly journals Evidence Supporting a Role for TopBP1 and Brd4 in the Initiation but Not Continuation of Human Papillomavirus 16 E1/E2-Mediated DNA Replication

2015 ◽  
Vol 89 (9) ◽  
pp. 4980-4991 ◽  
Author(s):  
Elaine J. Gauson ◽  
Mary M. Donaldson ◽  
Edward S. Dornan ◽  
Xu Wang ◽  
Molly Bristol ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Dna Replication ◽  
Viral Proteins ◽  
Future Generations ◽  
Cellular Proteins ◽  
Origin Of Replication ◽  
Viral Dna ◽  
Viral Origin ◽  
Viral Dna Replication ◽  
Human Papillomavirus 16

ABSTRACTTo replicate the double-stranded human papillomavirus 16 (HPV16) DNA genome, viral proteins E1 and E2 associate with the viral origin of replication, and E2 can also regulate transcription from adjacent promoters. E2 interacts with host proteins in order to regulate both transcription and replication; TopBP1 and Brd4 are cellular proteins that interact with HPV16 E2. Previous work with E2 mutants demonstrated the Brd4 requirement for the transactivation properties of E2, while TopBP1 is required for DNA replication induced by E2 from the viral origin of replication in association with E1. More-recent studies have also implicated Brd4 in the regulation of DNA replication by E2 and E1. Here, we demonstrate that both TopBP1 and Brd4 are present at the viral origin of replication and that interaction with E2 is required for optimal initiation of DNA replication. Both cellular proteins are present in E1-E2-containing nuclear foci, and the viral origin of replication is required for the efficient formation of these foci. Short hairpin RNA (shRNA) against either TopBP1 or Brd4 destroys the E1-E2 nuclear bodies but has no effect on E1-E2-mediated levels of DNA replication. An E2 mutation in the context of the complete HPV16 genome that compromises Brd4 interaction fails to efficiently establish episomes in primary human keratinocytes. Overall, the results suggest that interactions between TopBP1 and E2 and between Brd4 and E2 are required to correctly initiate DNA replication but are not required for continuing DNA replication, which may be mediated by alternative processes such as rolling circle amplification and/or homologous recombination.IMPORTANCEHuman papillomavirus 16 (HPV16) is causative in many human cancers, including cervical and head and neck cancers, and is responsible for the annual deaths of hundreds of thousands of people worldwide. The current vaccine will save lives in future generations, but antivirals targeting HPV16 are required for the alleviation of disease burden on the current, and future, generations. Targeting viral DNA replication that is mediated by two viral proteins, E1 and E2, in association with cellular proteins such as TopBP1 and Brd4 would have therapeutic benefits. This report suggests a role for these cellular proteins in the initiation of viral DNA replication by HPV16 E1-E2 but not for continuing replication. This is important if viral replication is to be effectively targeted; we need to understand the viral and cellular proteins required at each phase of viral DNA replication so that it can be effectively disrupted.

scholarly journals An Adenovirus DNA Replication Factor, but Not Incoming Genome Complexes, Targets PML Nuclear Bodies

2015 ◽  
Vol 90 (3) ◽  
pp. 1657-1667 ◽  
Author(s):  
Tetsuro Komatsu ◽  
Kyosuke Nagata ◽  
Harald Wodrich
Keyword(s):  
Dna Replication ◽  
Nuclear Bodies ◽  
Viral Gene ◽  
Viral Dna ◽  
Dna Viruses ◽  
Viral Dna Replication ◽  
Viral Genomes ◽  
Replication Factor ◽  
Antiviral Responses ◽  
Pml Nuclear Bodies

ABSTRACTPromyelocytic leukemia protein nuclear bodies (PML-NBs) are subnuclear domains implicated in cellular antiviral responses. Despite the antiviral activity, several nuclear replicating DNA viruses use the domains as deposition sites for the incoming viral genomes and/or as sites for viral DNA replication, suggesting that PML-NBs are functionally relevant during early viral infection to establish productive replication. Although PML-NBs and their components have also been implicated in the adenoviral life cycle, it remains unclear whether incoming adenoviral genome complexes target PML-NBs. Here we show using immunofluorescence and live-cell imaging analyses that incoming adenovirus genome complexes neither localize at nor recruit components of PML-NBs during early phases of infection. We further show that the viral DNA binding protein (DBP), an early expressed viral gene and essential DNA replication factor, independently targets PML-NBs. We show that DBP oligomerization is required to selectively recruit the PML-NB components Sp100 and USP7. Depletion experiments suggest that the absence of one PML-NB component might not affect the recruitment of other components toward DBP oligomers. Thus, our findings suggest a model in which an adenoviral DNA replication factor, but not incoming viral genome complexes, targets and modulates PML-NBs to support a conducive state for viral DNA replication and argue against a generalized concept that PML-NBs target incoming viral genomes.IMPORTANCEThe immediate fate upon nuclear delivery of genomes of incoming DNA viruses is largely unclear. Early reports suggested that incoming genomes of herpesviruses are targeted and repressed by PML-NBs immediately upon nuclear import. Genome localization and/or viral DNA replication has also been observed at PML-NBs for other DNA viruses. Thus, it was suggested that PML-NBs may immediately sense and target nuclear viral genomes and hence serve as sites for deposition of incoming viral genomes and/or subsequent viral DNA replication. Here we performed a detailed analyses of the spatiotemporal distribution of incoming adenoviral genome complexes and found, in contrast to the expectation, that an adenoviral DNA replication factor, but not incoming genomes, targets PML-NBs. Thus, our findings may explain why adenoviral genomes could be observed at PML-NBs in earlier reports but argue against a generalized role for PML-NBs in targeting invading viral genomes.

scholarly journals The Inhibitory Action of P56 on Select Functions of E1 Mediates Interferon's Effect on Human Papillomavirus DNA Replication

2010 ◽  
Vol 84 (24) ◽  
pp. 13036-13039 ◽  
Author(s):  
Paramananda Saikia ◽  
Volker Fensterl ◽  
Ganes C. Sen
Keyword(s):  
Human Papillomavirus ◽  
Dna Replication ◽  
Dna Binding ◽  
Inhibitory Action ◽  
Dna Helicase ◽  
Single Amino Acid ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Hpv Dna ◽  
Papillomavirus Dna

ABSTRACT The interferon (IFN)-induced protein P56 inhibits human papillomavirus (HPV) DNA replication by binding to HPV E1, which has several distinct functions in initiating viral DNA replication. Here, we determined that P56 inhibited HPV type 18 (HPV18) E1's DNA helicase activity, E2 binding, and HPV Ori sequence-specific DNA binding but not nonspecific DNA binding. We observed that deletion of a single amino acid, F399, produced an E1 mutant that could not bind P56. This E1 mutant retained its ability to support Ori DNA replication, but this activity was not inhibited by IFN, demonstrating that P56 is the principal executor of the anti-HPV action of IFN.

scholarly journals An Interaction between Human Papillomavirus 16 E2 and TopBP1 Is Required for Optimum Viral DNA Replication and Episomal Genome Establishment

2012 ◽  
Vol 86 (23) ◽  
pp. 12806-12815 ◽  
Author(s):  
M. M. Donaldson ◽  
L. J. Mackintosh ◽  
J. M. Bodily ◽  
E. S. Dornan ◽  
L. A. Laimins ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Dna Replication ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Human Papillomavirus 16

scholarly journals A Noncanonical Function of Polycomb Repressive Complexes Promotes Human Cytomegalovirus Lytic DNA Replication and Serves as a Novel Cellular Target for Antiviral Intervention

2019 ◽  
Vol 93 (9) ◽  
Author(s):  
Adriana Svrlanska ◽  
Anna Reichel ◽  
Eva-Maria Schilling ◽  
Myriam Scherer ◽  
Thomas Stamminger ◽  
...  
Keyword(s):  
Dna Replication ◽  
Viral Replication ◽  
Human Cytomegalovirus ◽  
Cellular Proliferation ◽  
Antiviral Treatment ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Cellular Target ◽  
Core Components ◽  
Polycomb Repressive Complexes

ABSTRACTChromatin-based modifications of herpesviral genomes play a crucial role in dictating the outcome of infection. Consistent with this, host cell multiprotein complexes, such as polycomb repressive complexes (PRCs), were proposed to act as epigenetic regulators of herpesviral latency. In particular, PRC2 has recently been shown to contribute to the silencing of human cytomegalovirus (HCMV) genomes. Here, we identify a novel proviral role of PRC1 and PRC2, the two main polycomb repressive complexes, during productive HCMV infection. Western blot analyses revealed strong HCMV-mediated upregulation of RING finger protein 1B (RING1B) and B lymphoma Moloney murine leukemia virus insertion region 1 homolog (BMI1) as well as of enhancer of zeste homolog 2 (EZH2), suppressor of zeste 12 (SUZ12), and embryonic ectoderm development (EED), which constitute the core components of PRC1 and PRC2, respectively. Furthermore, we observed a relocalization of PRC components to viral replication compartments, whereas histone modifications conferred by the respective PRCs were specifically excluded from these sites. Depletion of individual PRC1/PRC2 proteins by RNA interference resulted in a significant reduction of newly synthesized viral genomes and, in consequence, a decreased release of viral particles. Furthermore, accelerated native isolation of protein on nascent DNA (aniPOND) revealed a physical association of EZH2 and BMI1 with nascent HCMV DNA, suggesting a direct contribution of PRC proteins to viral DNA replication. Strikingly, substances solely inhibiting the enzymatic activity of PRC1/2 did not exert antiviral effects, while drugs affecting the abundance of PRC core components strongly compromised HCMV genome synthesis and particle release. Taken together, our data reveal an enzymatically independent, noncanonical function of both PRC1 and PRC2 during HCMV DNA replication, which may serve as a novel cellular target for antiviral therapy.IMPORTANCEPolycomb group (PcG) proteins are primarily known as transcriptional repressors that modify chromatin and contribute to the establishment and maintenance of cell fates. Furthermore, emerging evidence indicates that overexpression of PcG proteins in various types of cancers contributes to the dysregulation of cellular proliferation. Consequently, several inhibitors targeting PcG proteins are presently undergoing preclinical and clinical evaluation. Here, we show that infection with human cytomegalovirus also induces a strong upregulation of several PcG proteins. Our data suggest that viral DNA replication depends on a noncanonical function of polycomb repressor complexes which is independent of the so-far-described enzymatic activities of individual PcG factors. Importantly, we observe that a subclass of inhibitory drugs that affect the abundance of PcG proteins strongly interferes with viral replication. This principle may serve as a novel promising target for antiviral treatment.

scholarly journals Viral DNA Replication Orientation and hnRNPs Regulate Transcription of the Human Papillomavirus 18 Late Promoter

mBio ◽  
2017 ◽  
Vol 8 (3) ◽  
Author(s):  
Xiaohong Wang ◽  
Haibin Liu ◽  
Hui Ge ◽  
Masahiko Ajiro ◽  
Nishi R. Sharma ◽  
...  
Keyword(s):  
Dna Replication ◽  
Transcription Initiation ◽  
Promoter Activity ◽  
Human Papillomaviruses ◽  
Keratinocyte Differentiation ◽  
Basal Cells ◽  
Late Promoter ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Sense Strand

ABSTRACTThe life cycle of human papillomaviruses (HPVs) is tightly linked to keratinocyte differentiation. Although expression of viral early genes is initiated immediately upon virus infection of undifferentiated basal cells, viral DNA amplification and late gene expression occur only in the mid to upper strata of the keratinocytes undergoing terminal differentiation. In this report, we show that the relative activity of HPV18 TATA-less late promoter P811depends on its orientation relative to that of the origin (Ori) of viral DNA replication and is sensitive to the eukaryotic DNA polymerase inhibitor aphidicolin. Additionally, transfected 70-nucleotide (nt)-long single-strand DNA oligonucleotides that are homologous to the region near Ori induce late promoter activity. We also found that promoter activation in raft cultures leads to production of the late promoter-associated, sense-strand transcription initiation RNAs (tiRNAs) and splice-site small RNAs (spliRNAs). Finally, acis-acting AAGTATGCA core element that functions as a repressor to the promoter was identified. This element interacts with hnRNP D0B and hnRNP A/B factors. Point mutations in the core prevented binding of hnRNPs and increased the promoter activity. Confirming this result, knocking down the expression of both hnRNPs in keratinocytes led to increased promoter activity. Taking the data together, our study revealed the mechanism of how the HPV18 late promoter is regulated by DNA replication and host factors.IMPORTANCEIt has been known for decades that the activity of viral late promoters is associated with viral DNA replication among almost all DNA viruses. However, the mechanism of how DNA replication activates the viral late promoter and what components of the replication machinery are involved remain largely unknown. In this study, we characterized the P811promoter region of HPV18 and demonstrated that its activation depends on the orientation of DNA replication. Using single-stranded oligonucleotides targeting the replication fork on either leading or lagging strands, we showed that viral lagging-strand replication activates the promoter. We also identified a transcriptional repressor element located upstream of the promoter transcription start site which interacts with cellular proteins hnRNP D0B and hnRNP A/B and modulates the late promoter activity. This is the first report on how DNA replication activates a viral late promoter.

scholarly journals Kaposi's Sarcoma-Associated Herpesvirus Deregulates Host Cellular Replication during Lytic Reactivation by Disrupting the MCM Complex through ORF59

2018 ◽  
Vol 92 (22) ◽  
Author(s):  
Roxanne Strahan ◽  
Prerna Dabral ◽  
Kammi Dingman ◽  
Christian Stadler ◽  
Kayla Hiura ◽  
...  
Keyword(s):  
Dna Replication ◽  
Dna Synthesis ◽  
Posttranslational Modifications ◽  
Viral Dna ◽  
Cellular Environment ◽  
Lytic Reactivation ◽  
Mcm Complex ◽  
Mcm Proteins ◽  
Cellular Replication ◽  
Cellular Dna

ABSTRACTMinichromosome maintenance proteins (MCMs) play an important role in DNA replication by binding to the origins as helicase and recruiting polymerases for DNA synthesis. During the S phase, MCM complex is loaded to limit DNA replication once per cell cycle. We identified MCMs as ORF59 binding partners in our protein pulldown assays, which led us to hypothesize that this interaction influences DNA replication. ORF59's interactions with MCMs were confirmed in both endogenous and overexpression systems, which showed its association with MCM3, MCM4, MCM5, and MCM6. Interestingly, MCM6 interacted with both the N- and C-terminal domains of ORF59, and its depletion in BCBL-1 and BC3 cells led to an increase in viral genome copies, viral late gene transcripts, and virion production compared to the control cells following reactivation. MCMs perform their function by loading onto the replication competent DNA, and one means of regulating chromatin loading/unloading, in addition to enzymatic activity of the MCM complex, is by posttranslational modifications, including phosphorylation of these factors. Interestingly, a hypophosphorylated form of MCM3, which is associated with reduced loading onto the chromatin, was detected during lytic reactivation and correlated with its inability to associate with histones in reactivated cells. Additionally, chromatin immunoprecipitation showed lower levels of MCM3 and MCM4 association at cellular origins of replication and decreased levels of cellular DNA synthesis in cells undergoing reactivation. Taken together, these findings suggest a mechanism in which KSHV ORF59 disrupts the assembly and functions of MCM complex to stall cellular DNA replication and promote viral replication.IMPORTANCEKSHV is the causative agent of various lethal malignancies affecting immunocompromised individuals. Both lytic and latent phases of the viral life cycle contribute to the progression of these cancers. A better understanding of how viral proteins disrupt functions of a normal healthy cell to cause oncogenesis is warranted. One crucial lytic protein produced early during lytic reactivation is the multifunctional ORF59. In this report, we elucidated an important role of ORF59 in manipulating the cellular environment conducive for viral DNA replication by deregulating the normal functions of the host MCM proteins. ORF59 binds to specific MCMs and sequesters them away from replication origins in order to sabotage cellular DNA replication. Blocking cellular DNA replication ensures that cellular resources are utilized for transcription and replication of viral DNA.

scholarly journals Different Modes of Human Papillomavirus DNA Replication during Maintenance

2006 ◽  
Vol 80 (9) ◽  
pp. 4431-4439 ◽  
Author(s):  
Ralf Hoffmann ◽  
Bernhard Hirt ◽  
Viviane Bechtold ◽  
Peter Beard ◽  
Kenneth Raj
Keyword(s):  
Human Papillomavirus ◽  
Dna Replication ◽  
S Phase ◽  
Basal Cells ◽  
Random Choice ◽  
Proliferating Cells ◽  
Hpv Dna ◽  
Viral Genomes ◽  
Viral Dnas ◽  
Keratinocyte Cell

ABSTRACT Human papillomavirus (HPV) begins its life cycle by infecting the basal cells of the epithelium. Within these proliferating cells, the viral genomes are replicated, maintained, and passed on to the daughter cells. Using HPV episome-containing cell lines that were derived from naturally infected cervical tissues, we investigated the mode by which the viral DNAs replicate in these cells. We observed that, whereas HPV16 DNA replicated in an ordered once-per-S-phase manner in W12 cells, HPV31 DNA replicated via a random-choice mechanism in CIN612 cells. However, when HPV16 and HPV31 DNAs were separately introduced into an alternate keratinocyte cell line NIKS, they both replicated randomly. This indicates that HPV DNA is inherently capable of replicating by either random-choice or once-per-S-phase mechanisms and that the mode of HPV DNA replication is dependent on the cells that harbor the viral episome. High expression of the viral replication protein E1 in W12 cells converted HPV16 DNA replication to random-choice replication and, as such, it appears that the mode of HPV DNA replication in proliferating cells is dependent on the presence or the increased level of this protein in the host cell. The implications of these observations on maintenance, latency, and persistence are discussed.

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