1.
Winquist, Ellenor, et al.
(författare)
Inefficient splicing of segment 7 and 8 mRNAs is an inherent property of influenza virus A/Brevig Mission/1918/1 (H1N1) that causes elevated expression of NS1 protein
2012
Ingår i: Virology. - : Elsevier BV. - 0042-6822 .- 1096-0341. ; 422:1, s. 46-58
Tidskriftsartikel (refereegranskat) abstract
Influenza A virus encodes two segments (7 and 8) that produce mRNAs that can be spliced. We have investigated if naturally occurring sequence polymorphisms in the influenza A virus family affects splicing of these viral mRNAs, as that could potentially alter the NS1/NS2- and/or M1/M2-protein ratios. We compared splicing efficiency of segment 7 and 8 mRNAs of A/Brevig Mission/1918/1 (H1N1) and A/Netherlands/178/95 (H3N2), as well as various H5N1 avian strains. Results revealed that both segment 7 and 8 mRNAs of A/Brevig Mission/1918/1 (H1N1) were inefficiently spliced compared to other influenza virus segment 7 and 8 mRNAs. This resulted in production of higher levels of functional NS1 protein, which could potentially contribute to the pathogenic properties of the A/Brevig Mission/1918/1 (H1N1). We also show that A/Brevig Mission/1918/1 (H1N1) segment 8 mRNAs responded differently to overexpression of SR proteins than A/Netherlands/178/95 (H3N2).
2.
Hao, Chengyu, et al.
(författare)
hnRNP G/RBMX enhances HPV16 E2 mRNA splicing through a novel splicing enhancer and inhibits production of spliced E7 oncogene mRNAs
2022
Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 50:7, s. 3867-3891
Tidskriftsartikel (refereegranskat) abstract
Human papillomavirus type 16 (HPV16) E2 is an essential HPV16 protein. We have investigated how HPV16 E2 expression is regulated and have identifed a splicing enhancer that is required for production of HPV16 E2 mRNAs. This uridine-less splicing enhancer sequence (ACGAGGACGAGGACAAGGA) contains 84% adenosine and guanosine and 16% cytosine and consists of three 'AC(A/G)AGG'-repeats. Mutational inactivation of the splicing enhancer reduced splicing to E2-mRNA specific splice site SA2709 and resulted in increased levels of unspliced E1-encoding mRNAs. The splicing enhancer sequence interacted with cellular RNA binding protein hnRNP G that promoted splicing to SA2709 and enhanced E2 mRNA production. The splicing-enhancing function of hnRNP G mapped to amino acids 236-286 of hnRNP G that were also shown to interact with splicing factor U2AF65. The interactions between hnRNP G and HPV16 E2 mRNAs and U2AF65 increased in response to keratinocyte differentiation as well as by the induction of the DNA damage response (DDR). The DDR reduced sumoylation of hnRNP G and pharmacological inhibition of sumoylation enhanced HPV16 E2 mRNA splicing and interactions between hnRNP G and E2 mRNAs and U2AF65. Intriguingly, hnRNP G also promoted intron retention of the HPV16 E6 coding region thereby inhibiting production of spliced E7 oncogene mRNAs.
3.
Wu, Troy Chengjun, et al.
(författare)
Splicing and polyadenylation of human papillomavirus type 16 mRNAs
2017
Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 18:2
Forskningsöversikt (refereegranskat) abstract
The human papillomavirus type 16 (HPV16) life cycle can be divided into an early stage in which the HPV16 genomic DNA is replicated, and a late stage in which the HPV16 structural proteins are synthesized and virions are produced. A strong coupling between the viral life cycle and the differentiation state of the infected cell is highly characteristic of all HPVs. The switch from the HPV16 early gene expression program to the late requires a promoter switch, a polyadenylation signal switch and a shift in alternative splicing. A number of cis-acting RNA elements on the HPV16 mRNAs and cellular and viral factors interacting with these elements are involved in the control of HPV16 gene expression. This review summarizes our knowledge of HPV16 cis-acting RNA elements and cellular and viral trans-acting factors that regulate HPV16 gene expression at the level of splicing and polyadenylation.
4.
Cui, Xiaoxu, et al.
(författare)
HnRNP D activates production of HPV16 E1 and E6 mRNAs by promoting intron retention
2022
Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 50:5, s. 2782-2806
Tidskriftsartikel (refereegranskat) abstract
Human papillomavirus type 16 (HPV16) E1 and E6 proteins are produced from mRNAs with retained introns, but it has been unclear how these mRNAs are generated. Here, we report that hnRNP D act as a splicing inhibitor of HPV16 E1/E2- and E6/E7-mRNAs thereby generating intron-containing E1- and E6-mRNAs, respectively. N- and C-termini of hnRNP D contributed to HPV16 mRNA splicing control differently. HnRNP D interacted with the components of splicing machinery and with HPV16 RNA to exert its inhibitory function. As a result, the cytoplasmic levels of intron-retained HPV16 mRNAs were increased in the presence of hnRNP D. Association of hnRNP D with HPV16 mRNAs in the cytoplasm was observed, and this may correlate with unexpected inhibition of HPV16 E1- and E6-mRNA translation. Notably, hnRNP D40 interacted with HPV16 mRNAs in an HPV16-driven tonsillar cancer cell line and in HPV16-immortalized human keratinocytes. Furthermore, knockdown of hnRNP D in HPV16-driven cervical cancer cells enhanced production of the HPV16 E7 oncoprotein. Our results suggest that hnRNP D plays significant roles in the regulation of HPV gene expression and HPV-associated cancer development.
5.
Cui, Xiaoxu, et al.
(författare)
Overexpression of m6A-factors METTL3, ALKBH5, and YTHDC1 alters HPV16 mRNA splicing.
2022
Ingår i: Virus genes. - : Springer. - 0920-8569 .- 1572-994X. ; 58:2, s. 98-112
Tidskriftsartikel (refereegranskat) abstract
We report that overexpression of the m6A-demethylase alkB homolog 5 RNA demethylase (ALKBH5) promoted production of intron retention on the human papillomavirus type 16 (HPV16) E6 mRNAs thereby promoting E6 mRNA production. ALKBH5 also altered alternative splicing of the late L1 mRNA by an exon skipping mechanism. Knock-down of ALKBH5 had the opposite effect on splicing of these HPV16 mRNAs. Overexpression of the m6A-methylase methyltransferase-like protein 3 (METLL3) induced production of intron-containing HPV16 E1 mRNAs over spliced E2 mRNAs and altered HPV16 L1 mRNA splicing in a manner opposite to ALKBH5. Overexpression of the nuclear m6A-"reader" YTH domain-containing protein 1 (YTHDC1), enhanced retention of the E6-encoding intron and promoted E6 mRNA production. We also show that HPV16 mRNAs are bound to YTHDC1 in human cells and that YTHDC1 affected splicing of HPV16 E6/E7 mRNAs produced from the episomal form of the HPV16 genome. Finally, we show that HPV16 mRNAs are m6A-methylated in tonsillar cancer cells. In summary, HPV16 mRNAs are methylated in HPV16-infected tonsillar cancer cells and overexpression of m6A-"writer" METTL3, m6A-"eraser" ALKBH5 and the m6A-"reader" YTHDC1 affected HPV16 mRNA splicing, suggesting that m6A plays an important role in the HPV16 gene expression program, at least in cancer cells.
6.
Dhanjal, Soniya, et al.
(författare)
Heterogeneous Nuclear Ribonucleoprotein C Proteins Interact with the Human Papillomavirus Type 16 (HPV16) Early 3'-Untranslated Region and Alleviate Suppression of HPV16 Late L1 mRNA Splicing.
2015
Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 290:21, s. 13354-71
Tidskriftsartikel (refereegranskat) abstract
In order to identify cellular factors that regulate human papillomavirus type 16 (HPV16) gene expression, cervical cancer cells permissive for HPV16 late gene expression were identified and characterized. These cells either contained a novel spliced variant of the L1 mRNAs that bypassed the suppressed HPV16 late, 5'-splice site SD3632; produced elevated levels of RNA-binding proteins SRSF1 (ASF/SF2), SRSF9 (SRp30c), and HuR that are known to regulate HPV16 late gene expression; or were shown by a gene expression array analysis to overexpress the RALYL RNA-binding protein of the heterogeneous nuclear ribonucleoprotein C (hnRNP C) family. Overexpression of RALYL or hnRNP C1 induced HPV16 late gene expression from HPV16 subgenomic plasmids and from episomal forms of the full-length HPV16 genome. This induction was dependent on the HPV16 early untranslated region. Binding of hnRNP C1 to the HPV16 early, untranslated region activated HPV16 late 5'-splice site SD3632 and resulted in production of HPV16 L1 mRNAs. Our results suggested that hnRNP C1 controls HPV16 late gene expression.
7.
Forslund, Ola, et al.
(författare)
Viral load and mRNA expression of HPV type 6 among cases with recurrent respiratory papillomatosis
2016
Ingår i: The Laryngoscope. - : Wiley. - 0023-852X .- 1531-4995. ; 126:1, s. 122-127
Tidskriftsartikel (refereegranskat) abstract
OBJECTIVES/HYPOTHESIS: To determine viral load of human papillomavirus type 6 (HPV6), physical state of HPV6-DNA, and transcription level of HPV6 E7-mRNA in laryngeal papilloma and in adjacent healthy mucosa.STUDY DESIGN: Case series.METHODS: A papilloma biopsy was collected from each of 25 adult patients with respiratory recurrent papillomatosis. From 14 of the 25 patients, we first collected a biopsy from healthy mucosa of the false vocal fold and another from the papilloma. Quantity of HPV6 and E7-mRNA was measured by polymerase chain reaction.RESULTS: For the papilloma, the median load of HPV6 was 41 copies/cell, and the lowest amount was 5.4 copies/cell. Human papillomavirus type 6 was detected in 50% (7/14) of the healthy mucosa, with a median of 1.1 copies/cell, and the highest amount was 6.6 copies/cell. Overall, viral load was higher in papilloma than in healthy mucosa (P < 0.05). The average HPV6 E2/E7-DNA ratio was 1.3, indicating an episomal state. Human papillomavirus type 6-mRNA was detected in all HPV6-DNA-positive samples. The transcription median ratio of HPV6-mRNA/HPV6-DNA was 1.5 in papilloma and 3.8 in healthy mucosa.CONCLUSION: The amount of HPV6-DNA was consistently higher in the papilloma than in healthy mucosa. The transcription level of HPV6 E7 mRNA was similar in the papilloma and in normal mucosa. We suggest that interfering with replication of HPV6 and suppression of HPV6 to fewer than five copies/cell may be curative.LEVEL OF EVIDENCE: N/A. Laryngoscope, 126:122-127, 2016.
8.
Hao, Chengyu, et al.
(författare)
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
2022
Ingår i: Archives of Virology. - : Springer Science and Business Media LLC. - 0304-8608 .- 1432-8798. ; 167:2, s. 563-570
Tidskriftsartikel (refereegranskat) abstract
We 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.
9.
Johansson, Cecilia, et al.
(författare)
Acetylation of intragenic histones on HPV16 correlates with enhanced HPV16 gene expression.
2015
Ingår i: Virology. - : Elsevier BV. - 0042-6822 .- 1096-0341. ; 482, s. 244-59
Tidskriftsartikel (refereegranskat) abstract
We report that many histone modifications are unevenly distributed over the HPV16 genome in cervical cancer cells as well as in HPV16-immortalized keratinocytes. For example, H3K36me3 and H3K9Ac that are common in highly expressed cellular genes and over exons, were more common in the early than in the late region of the HPV16 genome. In contrast, H3K9me3, H4K20me3, H2BK5me1 and H4K16Ac were more frequent in the HPV16 late region. Furthermore, a region encompassing the HPV16 early polyadenylation signal pAE displayed high levels of histone H3 acetylation. Histone deacetylase (HDAC) inhibitors caused a 2- to 8-fold induction of HPV16 early and late mRNAs in cervical cancer cells and in immortalized keratinocytes, while at the same time increasing the levels of acetylated histones in the cells and on the HPV16 genome specifically. We concluded that increased histone acetylation on the HPV16 genome correlates with increased HPV16 gene expression.
10.
Johansson, Cecilia
(författare)
Proteins involved in HPV-16 pre-mRNA processing
2010
Ingår i: Current Topics in Virology. ; 8, s. 17-27
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt) abstract
Self-inactivating retroviruses are an attractive vector choice for long term and stable expression of therapeutic genes because of their ability to integrate into the host genome. However, their utility as a human therapeutic platform is dependent on stringent criteria for safety and efficacy. Therefore, targeting the vector to a specific cell or tissue type is of paramount importance. Numerous virus-engineering strategies have been developed that either modify the viral surface glycoproteins or regulate transgene expression in a tissue-specific manner. The former, termed transductional targeting, involves modifying the viral glycoproteins that are responsible for binding to specific cellular receptors and facilitating entry into the host cell. The goal of this strategy is to develop a targeted, injectable retroviral based vector that will deliver the transgene to a specific cell or tissue type while leaving non-target tissue unharmed. Recently, the field has seen a technical advance with the demonstration that retroviruses can be pseudotyped with the envelope glycoproteins of the measles virus. The measles hemagglutinin (H) protein is responsible for receptor recognition, and the fusion (F) protein catalyzes lipid membrane mixing and viral entry. The natural tropism of the measles H protein for its receptors has been completely eliminated, allowing retargeting by the display of ligands such as growth factors or single-chain antibodies (scFvs) on the C-terminal end. We summarize the progress to date with retargeting retroviral cores via pseudotyping with measles virus H and F glycoproteins.
