Identification of a 17-nucleotide splicing enhancer in HPV-16 L1 that counteracts the effect of multiple hnRNP A1-binding splicing silencers

Zhao, Xiaomin; Fay, Joanna; Lambkin, Helen; Schwartz, Stefan

doi:10.1016/j.virol.2007.08.002

Cited by 33 publications

(60 citation statements)

References 40 publications

(59 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1). HPV-16 late (44,58,61) or RNA elements that indirectly inhibit late gene expression by promoting early mRNA splicing (44) and polyadenylation (41,42,55,59) (Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

“…To investigate if PTB induced L2/L1 mRNAs specifically or if PTB could induce the expression of the spliced L1 mRNAs also ( Fig. 2A), cells were cotransfected with pCMVPTB1 and a mutant version of pBEL named pBELM (61) in which splicing silencers in the L1 coding region had been (44), splicing suppressor sequences at SD3632 (44), and multiple splicing silencers in the L1 coding region that suppress the use of SA5639 (58,61). Polyadenylation regulatory elements in the early UTR (59) and in the L2 region (41) inactivated ( Fig.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

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

Somberg

Zhao

Fröhlich

et al. 2008

J Virol

Self Cite

View full text Add to dashboard Cite

The HPV-16 life cycle is strictly linked to the differentiation stage of the infected cell, and late viral mRNAs are expressed only in differentiated cells (14,37,43). Since all known HPV-16 promoters are located in one end of the viral genome, late gene expression is strongly influenced by posttranscriptional gene regulation (62). Viral RNA elements and cellular RNA binding factors are therefore important players in HPV-16 gene regulation (39, 45). The activities of these RNA elements and factors are responsible for the inhibition of HPV-16 late gene expression in proliferating cells and contribute to the induction of late gene expression in differentiating cells (45). RNA elements in the late untranslated region (UTR) of HPV-1 (50, 54, 56), HPV-16 (28), and HPV-31 (12) have been shown to inhibit late gene expression. These elements appear to be conserved among HPVs (60) and were originally identified in bovine papillomavirus (17). Late UTRs from different HPVs interact with the elav-like HuR protein (3, 48). Other RNA elements that suppress HPV-16 late gene expression have been identified previously. For example, the L1 and L2 coding regions contain inhibitory RNA elements that prevent the expression of L1 and L2 from subgenomic expression plasmids (10,11,42,49,53). The RNA elements in the L1 coding region were later shown to coincide with splicing silencers that suppress SA5639 (61), the only 3Ј splice site used exclusively by late mRNAs, whereas the RNA elements in the L2 coding region are active primarily as positive regulators of the early poly(A) signal pAE (41), thereby indirectly inhibiting late gene expression (41). Polyadenylation elements in L2 were originally identified in HPV-31 (55). In addition, splicing inhibitory sequences surround SD3632, the only 5Ј splice site used exclusively by late mRNAs, and therefore suppress late gene expression in proliferating cells (44). Finally, a major splicing enhancer downstream of the early 3Ј splice site SA3358 directs splicing to the early region of the genome and promotes polyadenylation at pAE (44), indirectly inhibiting late gene expression (44). Together, cellular factors interacting with these elements regulate HPV-16 gene expression. While we have previously identified hnRNP A1 as a cellular factor that binds to the splicing silencers in the HPV-16 L1 coding region and inhibits late mRNA splicing (61), most of the transacting factors regulating HPV-16 late gene expression remain to be identified. We have therefore initiated a screen for cellular factors that can induce HPV-16 late gene expression in proliferating cells. MATERIALS AND METHODSPlasmid constructions. pBEL, pBELM, pBSplice, and pBSpliceM have been described previously (pBSplice was referred to as pC16L1L2splice) (61). pT1, pT2, pT3, pT4, pT9, pT10, pT1OPSA, and pOPSDM have also been described previously (44), as have pBearly and pBELMDPU (59) and p1-22 M (58). pC16L1 and pC16L1M have been described previously as pC16L1MUT123 (11).

show abstract

“…1). HPV-16 late (44,58,61) or RNA elements that indirectly inhibit late gene expression by promoting early mRNA splicing (44) and polyadenylation (41,42,55,59) (Fig. 1).…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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

Somberg

Zhao

Fröhlich

et al. 2008

J Virol

Self Cite

View full text Add to dashboard Cite

show abstract

“…These viral RNA cis elements (ESE and ESS) were originally discovered in bovine papillomavirus late pre-mRNAs (4,5,8,9) and later in HPV16 pre-mRNAs (12,14,21,22). In general, the ESE and ESS are bipartite elements (4,49), commonly located downstream of a suboptimal 3= splice site to regulate selection of an alternative upstream splice site by interaction with various cellular splicing factors (5,6,11,37,48,(50)(51)(52).…”

Section: Discussionmentioning

confidence: 99%

“…Alternative RNA splicing of the HPV polycistronic pre-mRNAs plays a crucial role in regulation of viral gene expression (2,3). Although the molecular mechanisms that regulate alternative RNA splicing of bovine papillomavirus type 1 (BPV-1) (4-11) and HPV16 pre-mRNA transcripts (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) have been extensively studied in the past, a full transcription map of HPV18 in productive infection, the second most prevalent high-risk HPV genotype in association with cervical cancer (23), was constructed only recently (24), and the mechanistic regulation of HPV18 RNA splicing remains poorly investigated. HPV18 pre-mRNAs are transcribed mainly from a major early promoter, P 55/102 , or a major late promoter, P 811 , although a few other, weak promoters exist in the virus genome (24,25).…”

mentioning

confidence: 99%

Serine/Arginine-Rich Splicing Factor 3 and Heterogeneous Nuclear Ribonucleoprotein A1 Regulate Alternative RNA Splicing and Gene Expression of Human Papillomavirus 18 through Two Functionally Distinguishable cis Elements

Ajiro

Tang

Doorbar

et al. 2016

J Virol

View full text Add to dashboard Cite

Human papillomavirus 18 (HPV18) is the second most common oncogenic HPV type associated with cervical, anogenital, and oropharyngeal cancers. Like other oncogenic HPVs, HPV18 encodes two major (one early and one late) polycistronic premRNAs that are regulated by alternative RNA splicing to produce a repertoire of viral transcripts for the expression of individual viral genes. However, RNA cis-regulatory elements and trans-acting factors contributing to HPV18 alternative RNA splicing remain unknown. In this study, an exonic splicing enhancer (ESE) in the nucleotide (nt) 3520 to 3550 region in the HPV18 genome was identified and characterized for promotion of HPV18 929^3434 splicing and E1^E4 production through interaction with SRSF3, a host oncogenic splicing factor differentially expressed in epithelial cells and keratinocytes. Introduction of point mutations in the SRSF3-binding site or knockdown of SRSF3 expression in cells reduces 929^3434 splicing and E1^E4 production but activates other, minor 929^3465 and 929^3506 splicing. Knockdown of SRSF3 expression also enhances the expression of E2 and L1 mRNAs. An exonic splicing silencer (ESS) in the HPV18 nt 612 to 639 region was identified as being inhibitory to the 233^416 splicing of HPV18 E6E7 pre-mRNAs via binding to hnRNP A1, a well-characterized, abundantly and ubiquitously expressed RNA-binding protein. Introduction of point mutations into the hnRNP A1-binding site or knockdown of hnRNP A1 expression promoted 233^416 splicing and reduced E6 expression. These data provide the first evidence that the alternative RNA splicing of HPV18 pre-mRNAs is subject to regulation by viral RNA cis elements and host trans-acting splicing factors. IMPORTANCEExpression of HPV18 genes is regulated by alternative RNA splicing of viral polycistronic pre-mRNAs to produce a repertoire of viral early and late transcripts. RNA cis elements and trans-acting factors contributing to HPV18 alternative RNA splicing have been discovered in this study for the first time. The identified ESS at the E7 open reading frame (ORF) prevents HPV18 233^416 splicing in the E6 ORF through interaction with a host splicing factor, hnRNP A1, and regulates E6 and E7 expression of the early E6E7 polycistronic pre-mRNA. The identified ESE at the E1^E4 ORF promotes HPV18 929^3434 splicing of both viral early and late pre-mRNAs and E1^E4 production through interaction with SRSF3. This study provides important observations on how alternative RNA splicing of HPV18 pre-mRNAs is subject to regulation by viral RNA cis elements and host splicing factors and offers potential therapeutic targets to overcome HPV-related cancer.H igh-risk human papillomavirus (HPV) is associated with more than 95% of cervical cancer, 40 to 90% of anogenital cancer, and 10 to 60% of oropharyngeal cancer with geographic variation (1). Two major polycistronic pre-mRNAs, early and late pre-mRNAs, are transcribed from the high-risk HPV genome. Alternative RNA splicing of the HPV polycistronic pre-mRNAs plays a crucial role in regu...

show abstract

“…HPV-16 splice donor SD3632 and splice acceptor SA5639 (Fig. 1A-B) are used exclusively by the late mRNAs and splicing silencers suppress the use of these splice sites in cervical cancer cells Zhao et al, 2007;. HPV-16 late gene expression is also indirectly inhibited by RNA elements that stimulate early mRNA splicing and polyadenylation Terhune et al, 1999;Zhao et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Development and validation of a novel reporter assay for human papillomavirus type 16 late gene expression

Orru¹,

Cunniffe²,

Ryan³

et al. 2012

Journal of Virological Methods

Self Cite

View full text Add to dashboard Cite

Identification of a 17-nucleotide splicing enhancer in HPV-16 L1 that counteracts the effect of multiple hnRNP A1-binding splicing silencers

Cited by 33 publications

References 40 publications

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

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

Serine/Arginine-Rich Splicing Factor 3 and Heterogeneous Nuclear Ribonucleoprotein A1 Regulate Alternative RNA Splicing and Gene Expression of Human Papillomavirus 18 through Two Functionally Distinguishable cis Elements

Development and validation of a novel reporter assay for human papillomavirus type 16 late gene expression

Contact Info

Product

Resources

About