scholarly journals Polypyrimidine Tract Binding Protein Induces Human Papillomavirus Type 16 Late Gene Expression by Interfering with Splicing Inhibitory Elements at the Major Late 5′ Splice Site, SD3632

2008 ◽  
Vol 82 (7) ◽  
pp. 3665-3678 ◽  
Author(s):  
Monika Somberg ◽  
Xiaomin Zhao ◽  
Monika Fröhlich ◽  
Magnus Evander ◽  
Stefan Schwartz
Keyword(s):  
Gene Expression ◽  
Human Papillomavirus ◽  
Splice Site ◽  
Late Gene ◽  
Polypyrimidine Tract ◽  
Late Gene Expression ◽  
Hpv 16 ◽  
Human Papillomavirus Type 16 ◽  
Polypyrimidine Tract Binding Protein ◽  
Cellular Factors

ABSTRACT We have initiated a screen for cellular factors that can induce human papillomavirus type 16 (HPV-16) late gene expression in human cancer cells. We report that the overexpression of polypyrimidine tract binding protein (PTB), also known as heterologous nuclear ribonucleoprotein I (hnRNP I), induces HPV-16 late gene expression in cells transfected with subgenomic HPV-16 plasmids or with full-length HPV-16 genomes and in persistently HPV-16-infected cells. In contrast, other hnRNPs such as hnRNP B1/A2, hnRNP F, and hnRNP Q do not induce HPV-16 late gene expression. PTB activates SD3632, the only 5′ splice site on the HPV-16 genome that is used exclusively by late mRNAs. PTB interferes with splicing inhibitory sequences located immediately upstream and downstream of SD3632, thereby activating late gene expression. One AU-rich PTB-responsive element was mapped to a 198-nucleotide sequence located downstream of SD3632. The deletion of this element induced HPV-16 late gene expression in the absence of PTB. Our results suggest that the overexpression of PTB interferes with cellular factors that interact with the inhibitory sequences. One may speculate that an increase in PTB levels or a reduction in the concentration of a PTB antagonist is required for the activation of HPV-16 late gene expression during the viral life cycle.

scholarly journals A Splicing Enhancer in the E4 Coding Region of Human Papillomavirus Type 16 Is Required for Early mRNA Splicing and Polyadenylation as Well as Inhibition of Premature Late Gene Expression

2005 ◽  
Vol 79 (18) ◽  
pp. 12002-12015 ◽  
Author(s):  
Margaret Rush ◽  
Xiaomin Zhao ◽  
Stefan Schwartz
Keyword(s):  
Gene Expression ◽  
Human Papillomavirus ◽  
Splice Site ◽  
Late Gene ◽  
Coding Region ◽  
Late Gene Expression ◽  
Hpv 16 ◽  
Human Papillomavirus Type 16 ◽  
Early Region ◽  
Splicing Enhancer

ABSTRACT Successful inhibition of human papillomavirus type 16 (HPV-16) late gene expression early in the life cycle is essential for persistence of infection, the highest risk factor for cervical cancer. Our study aimed to locate regulatory RNA elements in the early region of HPV-16 that influence late gene expression. For this purpose, subgenomic HPV-16 expression plasmids under control of the strong human cytomegalovirus immediate early promoter were used. An exonic splicing enhancer that firmly supported the use of the E4 3′ splice site at position 3358 in the early region of the HPV-16 genome was identified. The enhancer was mapped to a 65-nucleotide AC-rich sequence located approximately 100 nucleotides downstream of the position 3358 3′ splice site. Deletion of the enhancer caused loss of both splicing at the upstream position 3358 3′ splice site and polyadenylation at the early polyadenylation signal, pAE. Direct splicing occurred at the competing L1 3′ splice site at position 5639 in the late region. Optimization of the position 3358 3′ splice site restored splicing to that site and polyadenylation at pAE. Additionally, a sequence of 40 nucleotides with a negative effect on late mRNA production was located immediately downstream of the enhancer. As the E4 3′ splice site is employed by both early and late mRNAs, the enhancer constitutes a key regulator of temporal HPV-16 gene expression, which is required for early mRNA production as well as for the inhibition of premature late gene expression.

scholarly journals A Downstream Polyadenylation Element in Human Papillomavirus Type 16 L2 Encodes Multiple GGG Motifs and Interacts with hnRNP H

2005 ◽  
Vol 79 (14) ◽  
pp. 9254-9269 ◽  
Author(s):  
Daniel Öberg ◽  
Joanna Fay ◽  
Helen Lambkin ◽  
Stefan Schwartz
Keyword(s):  
Gene Expression ◽  
Human Papillomavirus ◽  
Polyadenylation Signal ◽  
Late Gene ◽  
Coding Region ◽  
Late Gene Expression ◽  
Hpv 16 ◽  
Virus Particles ◽  
Human Papillomavirus Type 16 ◽  
L1 And L2

ABSTRACT Production of human papillomavirus type 16 (HPV-16) virus particles is totally dependent on the differentiation-dependent induction of viral L1 and L2 late gene expression. The early polyadenylation signal in HPV-16 plays a major role in the switch from the early to the late, productive stage of the viral life cycle. Here, we show that the L2 coding region of HPV-16 contains RNA elements that are necessary for polyadenylation at the early polyadenylation signal. Consecutive mutations in six GGG motifs located 174 nucleotides downstream of the polyadenylation signal resulted in a gradual decrease in polyadenylation at the early polyadenylation signal. This caused read-through into the late region, followed by production of the late mRNAs encoding L1 and L2. Binding of hnRNP H to the various triple-G mutants correlated with functional activity of the HPV-16 early polyadenylation signal. In addition, the polyadenylation factor CStF-64 was also found to interact specifically with the region in L2 located 174 nucleotides downstream of the early polyadenylation signal. Staining of cervix epithelium with anti-hnRNP H-specific antiserum revealed high expression levels of hnRNP H in the lower layers of cervical epithelium and a loss of hnRNP H production in the superficial layers, supporting a model in which a differentiation-dependent down regulation of hnRNP H causes a decrease in HPV-16 early polyadenylation and an induction of late gene expression.

scholarly journals Identification of heterogenous nuclear ribonucleoproteins (hnRNPs) and serine- and arginine-rich (SR) proteins that induce human papillomavirus type 16 late gene expression and alter L1 mRNA splicing

2021 ◽  
Author(s):  
Chengyu Hao ◽  
Lijing Gong ◽  
Xiaoxu Cui ◽  
Johanna Jönsson ◽  
Yunji Zheng ◽  
...  
Keyword(s):  
Gene Expression ◽  
Human Papillomavirus ◽  
Sr Proteins ◽  
Mrna Splicing ◽  
Late Gene ◽  
Mrna Levels ◽  
Late Gene Expression ◽  
Human Papillomavirus Type 16 ◽  
Hnrnp Proteins ◽  
L1 And L2

AbstractWe have determined the effect of seven serine- and arginine-rich (SR) proteins and 15 heterogenous nuclear ribonucleoproteins (hnRNPs) on human papillomavirus type 16 (HPV16) late gene expression. Of the seven SR proteins analyzed here, SRSF1, SRSF3, and SRSF9 induced HPV16 late gene expression, and five of the SR proteins affected HPV16 L1 mRNA splicing. Of the 15 hnRNP proteins analyzed here, hnRNP A2, hnRNP F, and hnRNP H efficiently induced HPV16 late gene expression, and all of the hnRNPs affected HPV16 L1 mRNA levels or mRNA splicing. Thus, the majority of SR proteins and hnRNPs have the potential to regulate HPV16 L1 mRNA splicing. Strict control of the expression of the immunogenic L1 and L2 capsid proteins may contribute to the ability of HPV16 to cause persistence.

scholarly journals A 57-Nucleotide Upstream Early Polyadenylation Element in Human Papillomavirus Type 16 Interacts with hFip1, CstF-64, hnRNP C1/C2, and Polypyrimidine Tract Binding Protein

2005 ◽  
Vol 79 (7) ◽  
pp. 4270-4288 ◽  
Author(s):  
Xiaomin Zhao ◽  
Daniel Öberg ◽  
Margaret Rush ◽  
Joanna Fay ◽  
Helen Lambkin ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Binding Protein ◽  
Open Reading Frames ◽  
Polyadenylation Signal ◽  
Polypyrimidine Tract ◽  
Hpv 16 ◽  
Polypyrimidine Tract Binding ◽  
Human Papillomavirus Type 16 ◽  
Polypyrimidine Tract Binding Protein ◽  
Upstream Element

ABSTRACT We have investigated the role of the human papillomavirus type 16 (HPV-16) early untranslated region (3′ UTR) in HPV-16 gene expression. We found that deletion of the early 3′ UTR reduced the utilization of the early polyadenylation signal and, as a consequence, resulted in read-through into the late region and production of late L1 and L2 mRNAs. Deletion of the U-rich 3′ half of the early 3′ UTR had a similar effect, demonstrating that the 57-nucleotide U-rich region acted as an enhancing upstream element on the early polyadenylation signal. In accordance with this, the newly identified hFip1 protein, which has been shown to enhance polyadenylation through U-rich upstream elements, interacted specifically with the HPV-16 upstream element. This upstream element also interacted specifically with CstF-64, hnRNP C1/C2, and polypyrimidine tract binding protein, suggesting that these factors were either enhancing or regulating polyadenylation at the HPV-16 early polyadenylation signal. Mutational inactivation of the early polyadenylation signal also resulted in increased late mRNA production. However, the effect was reduced by the activation of upstream cryptic polyadenylation signals, demonstrating the presence of additional strong RNA elements downstream of the early polyadenylation signal that direct cleavage and polyadenylation to this region of the HPV-16 genome. In addition, we identified a 3′ splice site at genomic position 742 in the early region with the potential to produce E1 and E4 mRNAs on which the E1 and E4 open reading frames are preceded only by the suboptimal E6 AUG. These mRNAs would therefore be more efficiently translated into E1 and E4 than previously described HPV-16 E1 and E4 mRNAs on which E1 and E4 are preceded by both E6 and E7 AUGs.

scholarly journals Identification of an hnRNP A1-Dependent Splicing Silencer in the Human Papillomavirus Type 16 L1 Coding Region That Prevents Premature Expression of the Late L1 Gene

2004 ◽  
Vol 78 (20) ◽  
pp. 10888-10905 ◽  
Author(s):  
Xiaomin Zhao ◽  
Margaret Rush ◽  
Stefan Schwartz
Keyword(s):  
Human Papillomavirus ◽  
Splice Site ◽  
Early Stage ◽  
Eukaryotic Expression ◽  
Hnrnp A1 ◽  
Coding Region ◽  
Late Gene Expression ◽  
Hpv 16 ◽  
Human Papillomavirus Type 16 ◽  
Splicing Silencer

ABSTRACT We have previously identified cis-acting RNA sequences in the human papillomavirus type 16 (HPV-16) L1 coding region which inhibit expression of L1 from eukaryotic expression plasmids. Here we have determined the function of one of these RNA elements, and we provide evidence that this RNA element is a splicing silencer which suppresses the use of the 3′ splice site located immediately upstream of the L1 AUG. We also show that this splice site is inefficiently utilized as a result of a suboptimal polypyrimidine tract. Introduction of point mutations in the L1 coding region that altered the RNA sequence without affecting the L1 protein sequence resulted in the inactivation of the splicing silencer and induced splicing to the L1 3′ splice site. These mutations also prevented the interaction of the RNA silencer with a 35-kDa cellular protein identified here as hnRNP A1. The splicing silencer in L1 inhibits splicing in vitro, and splicing can be restored by the addition of RNAs containing an hnRNP A1 binding site to the reaction, demonstrating that hnRNP A1 inhibits splicing of the late HPV-16 mRNAs through the splicing silencer sequence. While we show that one role of the splicing silencer is to determine the ratio between partially spliced L2/L1 mRNAs and spliced L1 mRNAs, we also demonstrate that it inhibits splicing from the major 5′ splice site in the early region to the L1 3′ splice site, thereby playing an essential role in preventing late gene expression at an early stage of the viral life cycle. We speculate that the activity of the splicing silencer and possibly the concentration of hnRNP A1 in the HPV-16-infected cell determines the ability of the virus to establish a persistent infection which remains undetected by the host immune surveillance.

scholarly journals Human papillomavirus type 16 late gene expression is regulated by cellular RNA processing factors in response to epithelial differentiation

2008 ◽  
Vol 36 (3) ◽  
pp. 522-524 ◽  
Author(s):  
Sarah A. Cumming ◽  
Thanaporn Cheun-Im ◽  
Stephen G. Milligan ◽  
Sheila V. Graham
Keyword(s):  
Gene Expression ◽  
Human Papillomavirus ◽  
Current Knowledge ◽  
Regulatory Element ◽  
Epithelial Differentiation ◽  
Late Gene ◽  
Coding Region ◽  
Late Gene Expression ◽  
Human Papillomavirus Type 16 ◽  
L1 And L2

HPV16 (human papillomavirus type 16) is a 7.9 kb double-stranded DNA virus that infects anogenital mucosal epithelia. In some rare cases, in women, infection can progress to cervical cancer. HPV16 gene expression is regulated through use of multiple promoters and alternative splicing and polyadenylation. The virus genome can be divided into an early and a late coding region. The late coding region contains the L1 and L2 genes. These encode the virus capsid proteins L1 and L2; protein expression is confined to the upper epithelial layers and is regulated post-transcriptionally in response to epithelial differentiation. A 79 nt RNA regulatory element, the LRE (late regulatory element), involved in this regulation is sited at the 3′-end of the L1 gene and extends into the late 3′-UTR (3′-untranslated region). This element represses late gene expression in differentiated epithelial cells and may activate it in differentiated cells. The present paper describes our current knowledge of LRE RNA–protein interaction and their possible functions.

Human Papillomavirus Type 16 Infection: A Morphological Spectrum with Evidence for Late Gene Expression

1987 ◽  
Vol 42 (8) ◽  
pp. 527-528
Author(s):  
MASARU MITAO ◽  
NOBUTAKA NAGAI ◽  
RICHARD U. LEVINE ◽  
SAUL J. SILVERSTEIN ◽  
CHRISTOPHER P. CRUM
Keyword(s):  
Gene Expression ◽  
Human Papillomavirus ◽  
Late Gene ◽  
Late Gene Expression ◽  
Human Papillomavirus Type 16

scholarly journals The Human Papillomavirus Type 31 Late 3′ Untranslated Region Contains a Complex Bipartite Negative Regulatory Element

2002 ◽  
Vol 76 (12) ◽  
pp. 5993-6003 ◽  
Author(s):  
Sarah A. Cumming ◽  
Claire E. Repellin ◽  
Maria McPhillips ◽  
Jonathan C. Radford ◽  
J. Barklie Clements ◽  
...  
Keyword(s):  
Gene Expression ◽  
Human Papillomavirus ◽  
High Risk ◽  
Epithelial Cells ◽  
Regulatory Element ◽  
Capsid Proteins ◽  
Cellular Proteins ◽  
Late Gene Expression ◽  
Hpv 16 ◽  
Negative Regulatory Element

ABSTRACT The papillomavirus life cycle is tightly linked to epithelial cell differentiation. Production of virus capsid proteins is restricted to the most terminally differentiated keratinocytes in the upper layers of the epithelium. However, mRNAs encoding the capsid proteins can be detected in less-differentiated cells, suggesting that late gene expression is controlled posttranscriptionally. Short sequence elements (less than 80 nucleotides in length) that inhibit gene expression in undifferentiated epithelial cells have been identified in the late 3′ untranslated regions (UTRs) of several papillomaviruses, including the high-risk mucosal type human papillomavirus type 16 (HPV-16). Here we show that closely related high-risk mucosal type HPV-31 also contains elements that can act to repress gene expression in undifferentiated epithelial cells. However, the HPV-31 negative regulatory element is surprisingly complex, comprising a major inhibitory element of approximately 130 nucleotides upstream of the late polyadenylation site and a minor element of approximately 110 nucleotides mapping downstream. The first 60 nucleotides of the major element have 68% identity to the negative regulatory element of HPV-16, and these elements bind the same cellular proteins, CstF-64, U2AF65, and HuR. The minor inhibitory element binds some cellular proteins in common with the major inhibitory element, though it also binds certain proteins that do not bind the upstream element.

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.

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