Early Polyadenylation Signals of Human Papillomavirus Type 31 Negatively Regulate Capsid Gene Expression

Terhune, Scott S.; Hubert, Walter G.; Thomas, Jennifer T.; Laimins, Laimonis A.

doi:10.1128/jvi.75.17.8147-8157.2001

Cited by 43 publications

(53 citation statements)

References 47 publications

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“…We wished to determine whether binding of any of these proteins was functionally important and whether the splice site mutant NREs that showed altered ability to inhibit reporter gene expression showed changes in protein binding. The NRE deletion mutant probes were 32 P labeled and UV cross-linked to HeLa cell nuclear extracts. All the deletion constructs differed from the wild-type NRE in the number and relative intensity of bands produced, although several proteins between 40 and 70 kDa appeared to bind to every deletion mutant tested.…”

Section: Site-directed and Deletion Mutant Analysis Of Hpv-16 Nre Funmentioning

confidence: 99%

“…This suggests that late gene expression in undifferentiated cells is regulated posttranscriptionally. Elements that inhibit gene expression in undifferentiated cells have been identified in the open reading frames of HPV-16 L1 (31) and L2 (4,27) and of HPV-31 L1 (32). Inhibitory RNA elements also occur in the late 3Ј UTRs of HPV-16 (18), bovine papillomavirus type 1 (BPV-1) (9), HPV-1 (26,30), and HPV-31 (5).…”

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confidence: 99%

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Activity of the Human Papillomavirus Type 16 Late Negative Regulatory Element Is Partly due to Four Weak Consensus 5′ Splice Sites That Bind a U1 snRNP-Like Complex

Cumming

McPhillips

Veerapraditsin

et al. 2003

J Virol

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The human papillomavirus (HPV) life cycle is tightly linked to differentiation of the squamous epithelia that it infects. Capsid proteins, and hence mature virions, are produced in the outermost layer of differentiated cells. As late gene transcripts are produced in the lower layers, posttranscriptional mechanisms likely prevent capsid protein production in less differentiated cells. For HPV type 16 (HPV-16), a 79-nucleotide (nt) negative regulatory element (NRE) inhibits gene expression in basal epithelial cells. To identify key NRE sequences, we carried out transient transfection in basal epithelial cells with reporter constructs containing the HPV-16 late 3 untranslated region with deletions and mutations of the NRE. Reporter gene expression was increased over 40-fold by deletion of the entire element, 10-fold by deletion of the 5 portion of the NRE that contains four weak consensus 5 splice sites, and only 3-fold by deletion of the 3 GU-rich region. Both portions of the element appear to be necessary for full repression. Inactivating mutations in the 5 splice sites in the 5 NRE partially alleviated repression in the context of the 79-nt NRE but caused full derepression when assayed in a construct with the 3 NRE deleted. All four contribute to the inhibitory effect, though the second splice site is most inhibitory. Sm proteins, U1A and U1 snRNA, but not U1 70K, could be affinity purified with the wild-type NRE but not with the NRE containing mutations in the 5 splice sites, indicating that a U1 snRNP-like complex forms upon the element.Human papillomaviruses (HPVs) are small DNA viruses that specifically infect squamous epithelial cells, giving rise to warts or papillomas (16). They may be divided into mucosal or cutaneous types and also into high-or low-risk types, depending on the probability of the lesions that they cause becoming malignant. High-risk mucosal types, which include HPV type 16 (HPV-16), HPV-18, HPV-31, HPV-33, and HPV-45, may give rise to cervical intraepithelial neoplasias and cervical carcinomas. HPV-16 is the most clinically significant of these, being found in over 50% of such cervical lesions (36).The early genes of the 8-kb HPV-16 genome encode proteins involved in the regulation of DNA replication, episomal maintenance of the genome, and control of host cell division. The late region encodes the major and minor capsid proteins, L1 and L2. The noncoding region contains the late gene 3Ј untranslated region (late 3Ј UTR) at its 5Ј end and regulatory sequences controlling activity of the viral promoter toward its 3Ј end (Fig. 1A). The major promoter in HPV-16, P 97 , is constitutively active from early in the viral life cycle (25). A second promoter, P 670 , also becomes active in differentiated cells (12). The genome consists of a single transcription unit, and alternative splicing generates individual mRNAs (7,17,23). Transcripts may be polyadenylated at the early polyadenylation [poly(A)] site; alternatively one of the tandem late poly(A) sites downstream of the L1 coding region may be...

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Section: Site-directed and Deletion Mutant Analysis Of Hpv-16 Nre Funmentioning

confidence: 99%

mentioning

confidence: 99%

Activity of the Human Papillomavirus Type 16 Late Negative Regulatory Element Is Partly due to Four Weak Consensus 5′ Splice Sites That Bind a U1 snRNP-Like Complex

Cumming

McPhillips

Veerapraditsin

et al. 2003

J Virol

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“…The binding sites for hnRNP H coincide with downstream RNA elements that stimulate HPV-16 early polyadenylation (Oberg et al, 2005). In HPV-31, the corresponding RNA sequence interacts with CstF-64 (Terhune et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Serine/arginine-rich protein 30c activates human papillomavirus type 16 L1 mRNA expression via a bimodal mechanism

Somberg

Johansson

et al. 2011

Journal of General Virology

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Two splice sites on the human papillomavirus type 16 (HPV-16) genome are used exclusively by the late capsid protein L1 mRNAs: SD3632 and SA5639. These splice sites are suppressed in mitotic cells. This study showed that serine/arginine-rich protein 30c (SRp30c), also named SFRS9, activated both SD3632 and SA5639 and induced production of L1 mRNA. Activation of HPV-16 L1 mRNA splicing by SRp30c required an intact arginine/serine-repeat (RS) domain of SRp30c. In addition to this effect, SRp30c could enhance L1 mRNA production indirectly by inhibiting the early 39-splice site SA3358, which competed with the late 39-splice site SA5639. SRp30c bound directly to sequences downstream of SA3358, suggesting that SRp30c inhibited the enhancer at SA3358 and caused a redirection of splicing to the late 39-splice site SA5639. This inhibitory effect of SRp30c was independent of its RS domain. These results suggest that SRp30c can activate HPV-16 L1 mRNA expression via a bimodal mechanism: directly by stimulating splicing to late splice sites and indirectly by inhibiting competing early splice sites.

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“…bovine papillomavirus type 1 (BPV-1) appears to contain downstream elements in the L2 coding region that affect early polyadenylation (5). Polyadenylation at the pAE in HPV-31 is dependent on RNA elements extending 800 nucleotides into the L2 coding region (42). It was shown that these elements encoded multiple binding sites for the CStF-64 polyadenylation factor, suggesting that these RNA elements in L2 acted in concert to promote early polyadenylation in HPV-31 (43).…”

mentioning

confidence: 99%

“…Interestingly, the number of triple-G motifs in the two different L2 probes correlated with the cross-linking efficiency of the 55-kDa protein, suggesting that the 55-kDa protein recognized triple-G motifs. (42,43). We therefore performed a number of UV cross-linking experiments to investigate if the CStF-64 protein also interacted with the HPV-16 L2 sequence and if CStF-64 was the 55-kDa factor.…”

mentioning

confidence: 99%

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

Öberg

Fay²,

Lambkin³

et al. 2005

J Virol

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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.The human papillomaviruses (HPVs) are small DNA tumor viruses (20). To date, more than 100 different types have been identified (12). Some of these HPV types, termed high-risk types, are associated with development of cancer of the uterine cervix, one of the most common cancers in women worldwide (35,50). HPV type 16 (HPV-16) is the most common high-risk type (51). The HPV genome can be divided into an early region and a late region, followed by the proximal early (pAE) and the distal late (pAL) polyadenylation signals, respectively (Fig. 1A) (4). A polyadenylation signal consists of an AA UAAA sequence located 10 to 30 nucleotides (nt) upstream of the cleavage site and a degenerate GU-rich sequence element about 30 nucleotides downstream of the cleavage site (45). Some polyadenylation signals are followed by G-rich downstream elements (2, 3). The weak binding of cleavage/polyadenylation specificity factor (CPSF) to the AAUAAA motif is enhanced by CStF binding to the downstream GU-rich element (45). Recently, it was shown that U-rich upstream polyadenylation elements interact with hFip-1, an integral part of CPSF (21). In the early stage of the viral life cycle, all viral transcripts are polyadenylated at the pAE, whereas both the pAE and the pAL are used in the late, productive stage of the infection (26). In response to differentiation of the HPV-infected cell, the use of the pAE is down regulated, resulting in read-through into the late region and polyadenylation of the late transcripts at the pAL. Efficient polyadenylation at the pAE is an absolute requirement for early...

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Early Polyadenylation Signals of Human Papillomavirus Type 31 Negatively Regulate Capsid Gene Expression

Cited by 43 publications

References 47 publications

Activity of the Human Papillomavirus Type 16 Late Negative Regulatory Element Is Partly due to Four Weak Consensus 5′ Splice Sites That Bind a U1 snRNP-Like Complex

Activity of the Human Papillomavirus Type 16 Late Negative Regulatory Element Is Partly due to Four Weak Consensus 5′ Splice Sites That Bind a U1 snRNP-Like Complex

Serine/arginine-rich protein 30c activates human papillomavirus type 16 L1 mRNA expression via a bimodal mechanism

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

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