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Sodroski CN, Oh HS, Chou SF, Knipe DM. Sp1 facilitates continued HSV-1 gene expression in the absence of key viral transactivators. mBio 2024; 15:e0347923. [PMID: 38349188 PMCID: PMC10936440 DOI: 10.1128/mbio.03479-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 01/17/2024] [Indexed: 03/14/2024] Open
Abstract
Productive replication of herpes simplex virus (HSV) relies upon a well-ordered transcriptional cascade flowing from immediate-early (IE) to early (E) to late (L) gene products. While several virus-encoded transcriptional activators are involved in this process, IE and E gene promoters also contain multiple binding sites for the ubiquitously expressed cellular transcription factor Sp1. Sp1 has been previously implicated in activating HSV-1 gene transcription downstream of these sites, but why Sp1-binding sites are maintained in the promoters of genes activated by virus-encoded activators remains unclear. We hypothesized that Sp1 enables continued HSV-1 transcription and replication when viral transactivators are limited. We used a depletion-based approach in human foreskin fibroblasts to investigate the specific contribution of Sp1 to the initiation and progression of the HSV-1 lytic gene cascade. We found that Sp1 increased viral transcript levels, protein expression, and replication following infection with VP16- or ICP0-deficient viruses but had little to no effect on rescued viruses or during wild-type (WT) HSV-1 infection. Moreover, Sp1 promoted WT virus transcription and replication following interferon treatment of fibroblasts and thus may contribute to viral immune evasion. Interestingly, we observed reduced expression of Sp1 and Sp1-family transcription factors in differentiated sensory neurons compared to undifferentiated cells, suggesting that reduced Sp1 levels may also contribute to HSV-1 latent infection. Overall, these findings indicate that Sp1 can promote HSV-1 gene expression in the absence of key viral transactivators; thus, HSV-1 may use Sp1 to maintain its gene expression and replication under adverse conditions.IMPORTANCEHerpes simplex virus (HSV) is a common human pathogen that actively replicates in the epithelia but can persist for the lifetime of the infected host via a stable, latent infection in neurons. A key feature of the HSV replication cycle is a complex transcriptional program in which virus and host-cell factors coordinate to regulate expression of the viral gene products necessary for continued viral replication. Multiple binding sites for the cellular transcription factor Sp1 are located in the promoters of HSV-1 genes, but how Sp1 binding contributes to transcription and replication of wild-type virus is not fully understood. In this study, we identified a specific role for Sp1 in maintaining HSV-1 gene transcription under adverse conditions, as when virus-encoded transcriptional activators were absent or limited. Preservation of Sp1-binding sites in HSV-1 gene promoters may thus benefit the virus as it navigates diverse cell types and host-cell conditions during infection.
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Affiliation(s)
- Catherine N. Sodroski
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
- Program in Virology, Harvard Medical School, Boston, Massachusetts, USA
| | - Hyung Suk Oh
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Shu-Fan Chou
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - David M. Knipe
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
- Program in Virology, Harvard Medical School, Boston, Massachusetts, USA
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2
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Thakur K, Janjua D, Aggarwal N, Chhokar A, Yadav J, Tripathi T, Chaudhary A, Senrung A, Shrivastav A, Bharti AC. Physical interaction between STAT3 and AP1 in cervical carcinogenesis: Implications in HPV transcription control. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166817. [PMID: 37532113 DOI: 10.1016/j.bbadis.2023.166817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/07/2023] [Accepted: 07/19/2023] [Indexed: 08/04/2023]
Abstract
The constitutive activation and aberrant expression of Signal Transducer and Activator of Transcription 3 (STAT3) plays a key role in initiation and progression of cervical cancer (CaCx). How STAT3 influences HPV transcription is poorly defined. In the present study, we probed direct and indirect interactions of STAT3 with HPV16/18 LCR. In silico assessment of cis-elements present on LCR revealed the presence of potential STAT3 binding motifs. However, experimental validation by ChIP-PCR could not confirm any specific STAT3 binding on HPV16 LCR. Protein-protein interaction (PPI) network analysis of STAT3 with other host transcription factors that bind LCR, highlighted the physical association of STAT3 with c-FOS and c-JUN. This was further confirmed in vitro by co-immunoprecipitation, where STAT3 co-immunoprecipitated with c-FOS and c-JUN in CaCx cells. The result was supported by immunocytochemical analysis and colocalization of STAT3 with c-FOS and c-JUN. Positive signals in proximity ligation assay validated physical interaction and colocalization of STAT3 with AP1. Colocalization of STAT3 with c-FOS and c-JUN increased upon IL-6 treatment and decreased post-Stattic treatment. Alteration of STAT3 expression affected the subcellular localization of c-FOS and c-JUN, along with the expression of viral oncoproteins (E6 and E7) in CaCx cells. High expression of c-JUN in tumor tissues correlated with poor prognosis in both HPV16 and HPV18 CaCx cohort whereas high expression of STAT3 correlated with poor prognosis in HPV18 CaCx lesions only. Overall, the data suggest an indirect interaction of STAT3 with HPV LCR via c-FOS and c-JUN and potentiate transcription of viral oncoproteins.
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Affiliation(s)
- Kulbhushan Thakur
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi (North Campus), New Delhi, India
| | - Divya Janjua
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi (North Campus), New Delhi, India
| | - Nikita Aggarwal
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi (North Campus), New Delhi, India
| | - Arun Chhokar
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi (North Campus), New Delhi, India; Department of Zoology, Deshbandhu College, University of Delhi, Delhi, India
| | - Joni Yadav
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi (North Campus), New Delhi, India
| | - Tanya Tripathi
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi (North Campus), New Delhi, India
| | - Apoorva Chaudhary
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi (North Campus), New Delhi, India
| | - Anna Senrung
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi (North Campus), New Delhi, India
| | - Anuraag Shrivastav
- Department of Biology, The University of Winnipeg, 515 Portage Avenue, Winnipeg, Manitoba, Canada; Paul Albrechtsen Research Institute CCMB, 675 McDermot Ave, Winnipeg, Manitoba, Canada
| | - Alok Chandra Bharti
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi (North Campus), New Delhi, India.
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3
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Genetic Diversity of HPV 16 and HPV 18 Based on Partial Long Control Region in Iranian Women. CANADIAN JOURNAL OF INFECTIOUS DISEASES AND MEDICAL MICROBIOLOGY 2022; 2022:4759871. [PMID: 35126798 PMCID: PMC8808245 DOI: 10.1155/2022/4759871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/28/2021] [Accepted: 01/11/2022] [Indexed: 11/24/2022]
Abstract
Background Human papillomavirus (HPV) 16 and HPV 18 account for 75% of all cervical cancers. The L1 gene, encoding the major surface protein (MSP), is used to classify HPV types (lineages and sublineages), genotypes, and intratypic variants. Therefore, this study aimed to investigate the lineages, sublineages, genetic variabilities, and mutation effects on transcription factor binding sites by using partial sequences of the HPV 16 and HPV 18 long control regions (LCRs) in these samples. Materials and Methods After DNA isolation from 56 positive samples, the LCR of HPV 16 and HPV 18 were amplified using specific primers, and phylogenetic trees were drawn through MEGA X. Compared to the reference sequences, single nucleotide polymorphisms (SNPs) were identified. The transcription binding sites were also evaluated using the online PROMO database. Results The LCRs of 52 samples were successfully sequenced. Overall, 81.58% of all HPV 16 variants belonged to the D1 sublineage, followed by A4 (13.16%), A1 (2.63%), and C1 (2.63%) sublineages. All HPV 18 isolates belonged to A sublineage, 92.85% to A3 sublineage, and 7.15% to A4 sublineage. Out of 27 SNPs in the HPV 16 LCR, A7382T, T7384G, C7387T, C7393G, A7431G, T7448C, and C7783A were HPV 16-specific. Also, among 14 SNPs in the HPV 18 LCR, C7577A and A7943T were not previously reported. An insertion (C) between 7432 and 7433 positions was identified in all studied HPV 16 variants. Besides, most of the HPV 16 mutations were embedded in the YY1, TFIID, Oct-2, and NF-1 binding sites, while c-Fos and MBF1, as the most common binding sites, were affected by HPV 18 LCR mutations. Conclusion The present results showed that D1 and A3 were the dominant sublineages of HPV 16 and HPV 18, respectively. Therefore, women infected with these variants need to be examined in further longitudinal studies to obtain more information about the oncogenic potential of these dominant variants in Iran. Besides, YY1, TFIID, Oct-2, NF-1, c-Fos, and MBF1 were the most frequent binding sites, which were influenced by the mutations.
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Zhu Y. Human Papillomavirus (HPV) Entry Inhibitors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1366:223-239. [DOI: 10.1007/978-981-16-8702-0_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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5
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Molecular and Phylogenetic Characterization of Novel Papillomaviruses Isolated from Oral and Anogenital Neoplasms of Japanese Macaques ( Macaca fuscata). Viruses 2021; 13:v13040630. [PMID: 33916990 PMCID: PMC8067741 DOI: 10.3390/v13040630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/31/2021] [Accepted: 04/02/2021] [Indexed: 12/04/2022] Open
Abstract
Papillomaviruses (PVs) are a diverse group of host species-specific DNA viruses, etiologically linked with various benign and malignant neoplasms of cutaneous and mucosal epithelia. Here, we describe the detection and characterization of the first two PVs naturally infecting Japanese macaques (Macaca fuscata), including the determination of their etiological association(s) with the development of original neoplasms. The molecular and phylogenetic analyses were performed on complete genome sequences of Macaca fuscata PV types 1 (MfuPV1) and 2 (MfuPV2), which were completely sequenced in samples of a malignant oral tumor and benign anogenital neoplasm of Japanese macaques, respectively. Subsequently, two type-specific quantitative real-time PCRs were developed to estimate viral loads of MfuPV1 and MfuPV2 and to evaluate their etiological roles. The in silico molecular analyses revealed that both viral genomes encode characteristic PV proteins with conserved functional domains and have a non-coding genomic region with regulatory sequences to regulate and complete the viral life cycle. However, additional experimental evidence is needed to finally confirm the presence and biological functionality of the molecular features of both novel PVs. While MfuPV1, together with PVs identified in other macaques, is classified into the Alphapapillomavirus (Alpha-PV) species 12, MfuPV2 is most likely a representative of the novel viral species within the Alpha-PV genus. Their relatively high viral loads suggest that both PVs are etiologically linked with the development of the original neoplasms.
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Aggarwal N, Yadav J, Thakur K, Bibban R, Chhokar A, Tripathi T, Bhat A, Singh T, Jadli M, Singh U, Kashyap MK, Bharti AC. Human Papillomavirus Infection in Head and Neck Squamous Cell Carcinomas: Transcriptional Triggers and Changed Disease Patterns. Front Cell Infect Microbiol 2020. [PMID: 33344262 DOI: 10.3389/fcimb.2020.537650,] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous group of cancers. Collectively, HNSCC ranks sixth in incidence rate worldwide. Apart from classical risk factors like tobacco and alcohol, infection of human papillomavirus (HPV) is emerging as a discrete risk factor for HNSCC. HPV-positive HNSCC represent a distinct group of diseases that differ in their clinical presentation. These lesions are well-differentiated, occur at an early age, and have better prognosis. Epidemiological studies have demonstrated a specific increase in the proportions of the HPV-positive HNSCC. HPV-positive and HPV-negative HNSCC lesions display different disease progression and clinical response. For tumorigenic-transformation, HPV essentially requires a permissive cellular environment and host cell factors for induction of viral transcription. As the spectrum of host factors is independent of HPV infection at the time of viral entry, presumably entry of HPV only selects host cells that are permissive to establishment of HPV infection. Growing evidence suggest that HPV plays a more active role in a subset of HNSCC, where they are transcriptionally-active. A variety of factors provide a favorable environment for HPV to become transcriptionally-active. The most notable are the set of transcription factors that have direct binding sites on the viral genome. As HPV does not have its own transcription machinery, it is fully dependent on host transcription factors to complete the life cycle. Here, we review and evaluate the current evidence on level of a subset of host transcription factors that influence viral genome, directly or indirectly, in HNSCC. Since many of these transcription factors can independently promote carcinogenesis, the composition of HPV permissive transcription factors in a tumor can serve as a surrogate marker of a separate molecularly-distinct class of HNSCC lesions including those cases, where HPV could not get a chance to infect but may manifest better prognosis.
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Affiliation(s)
- Nikita Aggarwal
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Joni Yadav
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Kulbhushan Thakur
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Rakhi Bibban
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Arun Chhokar
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Tanya Tripathi
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Anjali Bhat
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Tejveer Singh
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Mohit Jadli
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Ujala Singh
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Manoj K Kashyap
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India.,Amity Medical School, Stem Cell Institute, Amity University Haryana, Amity Education Valley Panchgaon, Gurugram, India
| | - Alok C Bharti
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
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7
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Aggarwal N, Yadav J, Thakur K, Bibban R, Chhokar A, Tripathi T, Bhat A, Singh T, Jadli M, Singh U, Kashyap MK, Bharti AC. Human Papillomavirus Infection in Head and Neck Squamous Cell Carcinomas: Transcriptional Triggers and Changed Disease Patterns. Front Cell Infect Microbiol 2020; 10:537650. [PMID: 33344262 PMCID: PMC7738612 DOI: 10.3389/fcimb.2020.537650] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 11/02/2020] [Indexed: 02/05/2023] Open
Abstract
Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous group of cancers. Collectively, HNSCC ranks sixth in incidence rate worldwide. Apart from classical risk factors like tobacco and alcohol, infection of human papillomavirus (HPV) is emerging as a discrete risk factor for HNSCC. HPV-positive HNSCC represent a distinct group of diseases that differ in their clinical presentation. These lesions are well-differentiated, occur at an early age, and have better prognosis. Epidemiological studies have demonstrated a specific increase in the proportions of the HPV-positive HNSCC. HPV-positive and HPV-negative HNSCC lesions display different disease progression and clinical response. For tumorigenic-transformation, HPV essentially requires a permissive cellular environment and host cell factors for induction of viral transcription. As the spectrum of host factors is independent of HPV infection at the time of viral entry, presumably entry of HPV only selects host cells that are permissive to establishment of HPV infection. Growing evidence suggest that HPV plays a more active role in a subset of HNSCC, where they are transcriptionally-active. A variety of factors provide a favorable environment for HPV to become transcriptionally-active. The most notable are the set of transcription factors that have direct binding sites on the viral genome. As HPV does not have its own transcription machinery, it is fully dependent on host transcription factors to complete the life cycle. Here, we review and evaluate the current evidence on level of a subset of host transcription factors that influence viral genome, directly or indirectly, in HNSCC. Since many of these transcription factors can independently promote carcinogenesis, the composition of HPV permissive transcription factors in a tumor can serve as a surrogate marker of a separate molecularly-distinct class of HNSCC lesions including those cases, where HPV could not get a chance to infect but may manifest better prognosis.
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Affiliation(s)
- Nikita Aggarwal
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Joni Yadav
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Kulbhushan Thakur
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Rakhi Bibban
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Arun Chhokar
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Tanya Tripathi
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Anjali Bhat
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Tejveer Singh
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Mohit Jadli
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Ujala Singh
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
| | - Manoj K. Kashyap
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
- Amity Medical School, Stem Cell Institute, Amity University Haryana, Amity Education Valley Panchgaon, Gurugram, India
| | - Alok C. Bharti
- Molecular Oncology Laboratory, Department of Zoology, University of Delhi, Delhi, India
- *Correspondence: Alok C. Bharti,
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8
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Liu Y, Li H, Pi R, Yang Y, Zhao X, Qi X. Current strategies against persistent human papillomavirus infection (Review). Int J Oncol 2019; 55:570-584. [PMID: 31364734 DOI: 10.3892/ijo.2019.4847] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 07/16/2019] [Indexed: 11/06/2022] Open
Abstract
Human papillomavirus (HPV) is the most common sexually transmitted infection, exhibiting a tropism for the epidermis and mucosae. The link between persistent HPV infection and malignancies involving the anogenital tract as well as the head and neck has been well‑established, and it is estimated that HPV‑related cancers involving various anatomical sites account for 4.5% of all human cancers. Current prophylactic vaccines against HPV have enabled the prevention of associated malignancies. However, the sizeable population base of current infection in whom prophylactic vaccines are not applicable, certain high‑risk HPV types not included in vaccines, and the vast susceptible population in developing countries who do not have access to the costly prophylactic vaccines, put forward an imperative need for effective therapies targeting persistent infection. In this article, the life cycle of HPV, the mechanisms facilitating HPV evasion of recognition and clearance by the host immune system, and the promising therapeutic strategies currently under investigation, particularly antiviral drugs and therapeutic vaccines, are reviewed.
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Affiliation(s)
- Yu Liu
- Department of Gynecology and Obstetrics, Development and Related Diseases of Women and Children Key Laboratory of Sichuan Province, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Hongyi Li
- Department of Gynecology and Obstetrics, Development and Related Diseases of Women and Children Key Laboratory of Sichuan Province, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Ruyu Pi
- Department of Gynecology and Obstetrics, Development and Related Diseases of Women and Children Key Laboratory of Sichuan Province, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Yang Yang
- Department of Gynecology and Obstetrics, Development and Related Diseases of Women and Children Key Laboratory of Sichuan Province, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Xia Zhao
- Department of Gynecology and Obstetrics, Development and Related Diseases of Women and Children Key Laboratory of Sichuan Province, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Xiaorong Qi
- Department of Gynecology and Obstetrics, Development and Related Diseases of Women and Children Key Laboratory of Sichuan Province, Key Laboratory of Birth Defects and Related Diseases of Women and Children, Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
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9
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Auslander N, Wolf YI, Shabalina SA, Koonin EV. A unique insert in the genomes of high-risk human papillomaviruses with a predicted dual role in conferring oncogenic risk. F1000Res 2019; 8:1000. [PMID: 31448109 PMCID: PMC6685453 DOI: 10.12688/f1000research.19590.2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/17/2019] [Indexed: 12/12/2022] Open
Abstract
The differences between high risk and low risk human papillomaviruses (HR-HPV and LR-HPV, respectively) that contribute to the tumorigenic potential of HR-HPV are not well understood but can be expected to involve the HPV oncoproteins, E6 and E7. We combine genome comparison and machine learning techniques to identify a previously unnoticed insert near the 3’-end of the E6 oncoprotein gene that is unique to HR-HPV. Analysis of the insert sequence suggests that it exerts a dual effect, by creating a PDZ domain-binding motif at the C-terminus of E6, as well as eliminating the overlap between the E6 and E7 coding regions in HR-HPV. We show that, as a result, the insert might enable coupled termination-reinitiation of the E6 and E7 genes, supported by motifs complementary to the human 18S rRNA. We hypothesize that the added functionality of E6 and positive regulation of E7 expression jointly account for the tumorigenic potential of HR-HPV.
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Affiliation(s)
- Noam Auslander
- National Center for Biotechnology Information, National Institutes of Health, USA, Bethesda, Maryland, 20814, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Institutes of Health, USA, Bethesda, Maryland, 20814, USA
| | - Svetlana A Shabalina
- National Center for Biotechnology Information, National Institutes of Health, USA, Bethesda, Maryland, 20814, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Institutes of Health, USA, Bethesda, Maryland, 20814, USA
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10
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Biryukov J, Myers JC, McLaughlin-Drubin ME, Griffin HM, Milici J, Doorbar J, Meyers C. Mutations in HPV18 E1^E4 Impact Virus Capsid Assembly, Infectivity Competence, and Maturation. Viruses 2017; 9:v9120385. [PMID: 29257050 PMCID: PMC5744159 DOI: 10.3390/v9120385] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 01/24/2023] Open
Abstract
The most highly expressed protein during the productive phase of the human papillomavirus (HPV) life cycle is E1^E4. Its full role during infection remains to be established. HPV E1^E4 is expressed during both the early and late stages of the virus life cycle and contributes to viral genome amplification. In an attempt to further outline the functions of E1^E4, and determine whether it plays a role in viral capsid assembly and viral infectivity, we examined wild-type E1^E4 as well as four E1^E4 truncation mutants. Our study revealed that HPV18 genomes containing the shortest truncated form of E1^E4, the 17/18 mutant, produced viral titers that were similar to wild-type virus and significantly higher compared to virions containing the three longer E1^E4 mutants. Additionally, the infectivity of virus containing the shortest E1^E4 mutation was equivalent to wild-type and significantly higher than the other three mutants. In contrast, infectivity was completely abrogated for virus containing the longer E1^E4 mutants, regardless of virion maturity. Taken together, our results indicate for the first time that HPV18 E1^E4 impacts capsid assembly and viral infectivity as well as virus maturation.
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Affiliation(s)
- Jennifer Biryukov
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.B.); (J.C.M.); (M.E.M.-D.); (J.M.)
| | - Jocelyn C. Myers
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.B.); (J.C.M.); (M.E.M.-D.); (J.M.)
| | - Margaret E. McLaughlin-Drubin
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.B.); (J.C.M.); (M.E.M.-D.); (J.M.)
- Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02215, USA
| | - Heather M. Griffin
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK; (H.M.G.); (J.D.)
| | - Janice Milici
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.B.); (J.C.M.); (M.E.M.-D.); (J.M.)
| | - John Doorbar
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK; (H.M.G.); (J.D.)
| | - Craig Meyers
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA; (J.B.); (J.C.M.); (M.E.M.-D.); (J.M.)
- Correspondence: ; Tel.: +1-717-531-6240
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Abstract
Human papillomaviruses (HPV) are the major factor in causing cervical cancer as well as being implicated in causing oral and anal cancers. The life cycle of HPV is tied to the epithelial differentiation system, as only native virus can be produced in stratified human skin. Initially, HPV research was only possible utilizing recombinant systems in monolayer culture. With new cell culture technology, systems using differentiated skin have allowed HPV to be studied in its native environment. Here, we describe current research studying native virions in differentiated skin including viral assembly, maturation, capsid protein interactions, and L2 cross-neutralizing epitopes. In doing so, we hope to show how differentiating skin systems have increased our knowledge of HPV biology and identify gaps in our knowledge about this important virus.
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12
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Regulatory elements in the viral genome. Virology 2013; 445:197-204. [DOI: 10.1016/j.virol.2013.04.035] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 04/24/2013] [Accepted: 04/29/2013] [Indexed: 11/23/2022]
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13
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Schenker A, Straub E, Iftner T, Stubenrauch F. Cell-type-dependent activities of regulatory regions and E2 proteins derived from carcinogenic and non-carcinogenic human alphapapillomaviruses. J Gen Virol 2013; 94:1343-1350. [PMID: 23407419 DOI: 10.1099/vir.0.049072-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
A large number of studies have revealed that persistent infections with certain human papillomavirus (HPV) types are necessary for the development of invasive cancer of the cervix. Recent studies have shown that not only do the major carcinogenic HPV types 16 and 18 encode E6 and E7 oncoproteins with immortalizing activity but also the very weakly or non-carcinogenic types 53, 66, 70 and 82. Currently, it is unknown whether transcriptional differences exist between these viruses that account for carcinogenicity in vivo. Therefore, we compared for the first time the activities of the upstream regulatory regions (URRs) that drive E6 and E7 expression derived from HPV16, -18, -31, -53, -66, -70 and -82 in the absence and presence of the viral E2 transcriptional regulator. URR activities in the absence of E2 varied widely and were further modulated by the cellular background. The co-expression of homologous E2 proteins resulted in repression of the URRs of only some HPV types and this varied with cell type. Activation by E2 proteins was less cell-type dependent but differed in an HPV-type-dependent manner. However, basal URR activity, repression of the URR by E2 and transcriptional activation by E2 did not correlate with HPV carcinogenicity in vivo. In summary, our data do not support the model that the transcriptional activity of human alphapapillomavirus types correlates with epidemiological risk classification.
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Affiliation(s)
- Astrid Schenker
- University Hospital Tuebingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Division of Experimental Virology, Elfriede-Aulhorn-Str. 6, D72076 Tuebingen, Germany
| | - Elke Straub
- University Hospital Tuebingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Division of Experimental Virology, Elfriede-Aulhorn-Str. 6, D72076 Tuebingen, Germany
| | - Thomas Iftner
- University Hospital Tuebingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Division of Experimental Virology, Elfriede-Aulhorn-Str. 6, D72076 Tuebingen, Germany
| | - Frank Stubenrauch
- University Hospital Tuebingen, Institute for Medical Virology and Epidemiology of Viral Diseases, Division of Experimental Virology, Elfriede-Aulhorn-Str. 6, D72076 Tuebingen, Germany
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14
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Isolation of three novel rat and mouse papillomaviruses and their genomic characterization. PLoS One 2012; 7:e47164. [PMID: 23077564 PMCID: PMC3471917 DOI: 10.1371/journal.pone.0047164] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 09/10/2012] [Indexed: 11/25/2022] Open
Abstract
Despite a growing knowledge about the biological diversity of papillomaviruses (PV), only little is known about non-human PV in general and about PV mice models in particular. We cloned and sequenced the complete genomes of two novel PV types from the Norway rat (Rattus norvegicus; RnPV2) and the wood mouse (Apodemus sylvaticus; AsPV1) as well as a novel variant of the recently described MmuPV1 (originally designated as MusPV) from a house mouse (Mus musculus; MmuPV1 variant). In addition, we conducted phylogenetic analyses using a systematically representative set of 79 PV types, including the novel sequences. As inferred from concatenated amino acid sequences of six proteins, MmuPV1 variant and AsPV1 nested within the Beta+Xi-PV super taxon as members of the Pi-PV. RnPV2 is a member of the Iota-PV that has a distant phylogenetic position from Pi-PV. The phylogenetic results support a complex scenario of PV diversification driven by different evolutionary forces including co-divergence with hosts and adaptive radiations to new environments. PV types particularly isolated from mice and rats are the basis for new animal models, which are valuable to study PV induced tumors and new treatment options.
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15
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Snellenberg S, Schütze DM, Claassen-Kramer D, Meijer CJ, Snijders PJ, Steenbergen RD. Methylation status of the E2 binding sites of HPV16 in cervical lesions determined with the Luminex® xMAP™ system. Virology 2012; 422:357-65. [DOI: 10.1016/j.virol.2011.11.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 09/13/2011] [Accepted: 11/04/2011] [Indexed: 12/29/2022]
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16
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Yew CW, Lee P, Chan WK, Lim VKJ, Tay SK, Tan TMC, Deng LW. A novel MLL5 isoform that is essential to activate E6 and E7 transcription in HPV16/18-associated cervical cancers. Cancer Res 2011; 71:6696-707. [PMID: 21908553 DOI: 10.1158/0008-5472.can-11-1271] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Human papillomavirus (HPV) is the primary cause of human cervical cancer. The viral proteins E6 and E7 are essential to transform noncancerous epithelial cells into cancerous carcinomas by targeting key tumor suppressors p53 and retinoblastoma (Rb) proteins, respectively, but the cellular factors involved in E6 and E7 transcription themselves are incompletely understood. In this study, we defined a novel isoform of the mixed lineage leukemia 5 gene (MLL5β) as a specific and critical regulator of E6 and E7 transcription in cervical carcinoma cells. MLL5β is present in HPV16/18-positive cells including human primary cervical carcinoma specimens. Interaction of MLL5β with the AP-1-binding site at the distal region of the HPV18 long control region led to activation of E6/E7 transcription. Conversely, RNA interference-mediated knockdown of MLL5β downregulated both E6 and E7 expression. MLL5β downregulation was sufficient to restore p53 protein levels and reduce Rb phosphorylation, thereby reactivating apoptosis and cell-cycle checkpoints. By defining this novel MLL5β isoform and its specific critical role in activating E6/E7 gene transcription in HPV16/18-induced cervical cancers, our work highlights the potential of MLL5β as a biomarker and new therapeutic target in primary HPV-induced cervical cancers.
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Affiliation(s)
- Chow Wenn Yew
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore
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17
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In vivo analysis of the cell cycle dependent association of the bovine papillomavirus E2 protein and ChlR1. Virology 2011; 414:1-9. [PMID: 21489590 DOI: 10.1016/j.virol.2011.03.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 01/14/2011] [Accepted: 03/17/2011] [Indexed: 11/22/2022]
Abstract
It has been shown that the genomes of episomally maintained DNA viruses are tethered to host cell chromosomes during cell division, facilitating maintenance in dividing cells. The papillomavirus E2 protein serves this mechanism of viral genome persistence by simultaneously associating with chromatin and the viral genome during mitosis. Several host cell proteins are reported to be necessary for the association of E2 with chromatin including the cohesion establishment factor ChlR1. Here we use fluorescence resonance energy transfer (FRET) technology to confirm the interaction between BPV-1 E2 and ChlR1. Furthermore, we use synchronised live cells to study the temporal nature of this dynamic protein interaction and show that ChlR1 and E2 interact during specific phases of the cell cycle. These data provide evidence that the association of E2 with ChlR1 contributes to a loading mechanism during DNA replication rather than direct tethering during mitotic division.
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18
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Koczorowska MM, Kwasniewska A, Gozdzicka-Jozefiak A. IGF1 mRNA isoform expression in the cervix of HPV-positive women with pre-cancerous and cancer lesions. Exp Ther Med 2010; 2:149-156. [PMID: 22977483 DOI: 10.3892/etm.2010.174] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 11/22/2010] [Indexed: 01/02/2023] Open
Abstract
Human papillomavirus (HPV) plays a crucial role in cervical cancer etiology. However, not all HPV-infected women develop cancer, indicating that additional cellular factors facilitate carcinogenesis. The aim of this study was to analyze the expression profile of insulin-like growth factor 1 (IGF1) isoforms in the context of FOX2, SP1 and IGF1 receptor (IGF1R) expression during HPV-dependent cervical carcinogenesis. One hundred and nine epithelial tissue samples from women with pre-cancerous and cancer lesions of the cervix were analyzed. HPV DNA was identified by PCR, and real-time PCR was used to quantify the expression levels of the analyzed genes. All IGF1 mRNA splicing isoforms were up-regulated in pre-cancerous cells, and a shift in the balance towards mitogenic IGF1Eb was observed in the cancer samples. IGF1 expression was controlled mainly by the P1 promoter, and an increase in P2 usage was observed in the cancer. Correlations between IGF1 mRNA splicing isoforms and the FOX2 splicing factor, as well as P1/P2 activity and SP1 transcription factor expression levels were detected. No correlation was observed between the expression of IGF1 and its receptor IGF1R. Our results suggest that IGF1, in particular its splicing profile, may be an additional prognostic factor in cervical carcinogenesis.
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19
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Three novel papillomaviruses (HPV109, HPV112 and HPV114) and their presence in cutaneous and mucosal samples. Virology 2010; 397:331-6. [DOI: 10.1016/j.virol.2009.11.027] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 10/30/2009] [Accepted: 11/17/2009] [Indexed: 12/31/2022]
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20
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Chen Z, van Doorslaer K, DeSalle R, Wood CE, Kaplan JR, Wagner JD, Burk RD. Genomic diversity and interspecies host infection of alpha12 Macaca fascicularis papillomaviruses (MfPVs). Virology 2009; 393:304-10. [PMID: 19716580 DOI: 10.1016/j.virol.2009.07.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Accepted: 07/14/2009] [Indexed: 01/22/2023]
Abstract
Alpha human papillomaviruses (HPVs) are among the most common sexually transmitted agents of which a subset causes cervical neoplasia and cancer in humans. Alpha-PVs have also been identified in non-human primates although few studies have systematically characterized such types. We cloned and characterized 10 distinct types of PVs from exfoliated cervicovaginal cells from different populations of female cynomolgus macaques (Macaca fascicularis) originating from China and Indonesia. These include 5 novel genotypes and 5 previously identified genotypes found in rhesus (Macaca mulatta) (RhPV-1, RhPV-a, RhPV-b and RhPV-d) and cynomolgus macaques (MfPV-a). Type-specific primers were designed to amplify the complete PV genomes using an overlapping PCR method. Four MfPVs were associated with cervical intraepithelial neoplasia (CIN). The most prevalent virus type was MfPV-3 (formerly RhPV-d), which was identified in 60% of animals with CIN. In addition, the complete genomes of variants of MfPV-3 and RhPV-1 were characterized. These variants are 97.1% and 97.7% similar across the L1 nucleotide sequences with the prototype genomes, respectively. Sequence comparisons and phylogenetic analyses indicate that these novel MfPVs cluster together within the alpha12 PV species closely related to the alpha9 (e.g., HPV16) and alpha11 species (e.g., HPV34), and all share a most recent common ancestor. Our data expand the molecular diversity of non-human primate PVs and suggest a recent expansion of alpha-PV species groups. Moreover, identification of an overlapping set of MfPVs in rhesus and cynomolgus macaques indicates that non-human primate alpha-PVs might not be strictly species-specific and may represent past interspecies infection.
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Affiliation(s)
- Zigui Chen
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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21
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Abstract
Human papillomaviruses (HPVs) are small dsDNA tumor viruses, which are the etiologic agents of most cervical cancers and are associated with a growing percentage of oropharyngeal cancers. The HPV capsid is non-enveloped, having a T=7 icosahedral symmetry formed via the interaction among 72 pentamers of the major capsid protein, L1. The minor capsid protein L2 associates with L1 pentamers, although it is not known if each L1 pentamer contains a single L2 protein. The HPV life cycle strictly adheres to the host cell differentiation program, and as such, native HPV virions are only produced in vivo or in organotypic "raft" culture. Research producing synthetic papillomavirus particles--such as virus-like particles (VLPs), papillomavirus-based gene transfer vectors, known as pseudovirions (PsV), and papillomavirus genome-containing quasivirions (QV)--has bypassed the need for stratifying and differentiating host tissue in viral assembly and has allowed for the rapid analysis of HPV infectivity pathways, transmission, immunogenicity, and viral structure.
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Affiliation(s)
- M J Conway
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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22
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Thierry F. Transcriptional regulation of the papillomavirus oncogenes by cellular and viral transcription factors in cervical carcinoma. Virology 2008; 384:375-9. [PMID: 19064276 DOI: 10.1016/j.virol.2008.11.014] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Accepted: 11/04/2008] [Indexed: 12/30/2022]
Abstract
Human papillomaviruses (HPV) are small DNA viruses that contain a compact and non-redundant genome. HPV, with the help of only few genes, can achieve a complete vegetative cycle specifically in the epidermal and mucosal keratinocytes. Modification of the host cell transcriptional regulation is one of the major ways to regulate the viral production and maturation. The vegetative cycle of papillomaviruses is linked to terminal differentiation of the epithelium and is dependent on the host cell regulatory networks for transcriptional control. The mucosal high risk HPV16 and HPV18 types have been the main models to explore this transcriptional regulation mainly because they are prevalent in cervical cancer as the best studied virally induced cancers in human. In addition, the availability of cell lines, grown from cervical cancers containing integrated HPV16 or 18, represent versatile in vitro models for transcription studies. We will describe here some aspects of the transcriptional regulation that contribute to cell specificity, the basis of which is not yet fully understood despite efforts of numerous groups during the past two decades. Another specificity of small DNA viruses is the multifunctional characteristics of their regulatory proteins due to extreme genomic constraint. We will describe the role played by the viral E2 proteins in the transcriptional repression of the high risk HPV oncogenes and its implication in cervical cancer.
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23
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Chen Z, Schiffman M, Herrero R, Burk RD. Identification and characterization of two novel human papillomaviruses (HPVs) by overlapping PCR: HPV102 and HPV106. J Gen Virol 2007; 88:2952-2955. [PMID: 17947516 DOI: 10.1099/vir.0.83178-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Complete genomes of HPV102 (8,078 bp) and HPV106 (8,035 bp) were PCR amplified and cloned from cervicovaginal cells of a 49-year-old Hispanic female with reactive changes on her Pap test and a 42-year-old Hispanic female with a Pap test diagnosis of atypical squamous cells of unknown significance (ASCUS), respectively. The nucleotide sequence similarity of the complete L1 open reading frame (ORF) determined that HPV102 and HPV106 are most closely related to HPV83 (84.1 % identity) and HPV90 (83.5 % identity), respectively, placing them in the genital HPV groups, papillomaviruses species alpha3 and alpha15. HPV102 and HPV106 contain five early genes (E6, E7, E1, E2, and E4) and two late genes (L2 and L1), and both lack an E5 ORF. On the basis of phylogenetic analyses and available clinical information, these two novel HPV types expand the heterogeneity of HPVs detected in the lower genital tract.
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Affiliation(s)
- Zigui Chen
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Mark Schiffman
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, US Department of Health and Human Services, Bethesda, MD, USA
| | - Rolando Herrero
- Proyecto Epidemiológico Guanacaste, Costa Rican Foundation for Health Sciences, San José, Costa Rica
| | - Robert D Burk
- Department of Pediatrics, Department of Epidemiology and Population Health, Department of Obstetrics, Gynecology and Woman's Health and Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY, USA.,Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
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24
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Chen Z, Fu L, Herrero R, Schiffman M, Burk RD. Identification of a novel human papillomavirus (HPV97) related to HPV18 and HPV45. Int J Cancer 2007; 121:193-8. [PMID: 17351898 DOI: 10.1002/ijc.22632] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Human papillomavirus (HPV) type 97 was identified and the genome was cloned from cervicovaginal cells of a Costa Rican woman with a normal Pap smear. The HPV97 L1 open reading frame (ORF) was most closely related to HPV45 (84% identity) and HPV18 (79% identity), placing it into the high-risk alpha7 species. Ectopic expression of the HPV97 E6 and E7 proteins significantly decreased steady state p53 and pRb levels using an in vitro cotransfection assay, respectively. These data suggest that HPV97 shares a most recent common ancestor with HPV18 and HPV45 and should be evaluated in cancer specimens from different geographic populations.
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Affiliation(s)
- Zigui Chen
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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25
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Fradet-Turcotte A, Archambault J. Recent Advances in the Search for Antiviral Agents against Human Papillomaviruses. Antivir Ther 2007. [DOI: 10.1177/135965350701200417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Infection by human papillomavirus (HPV) is extremely common and associated with the development of benign warts or malignant lesions of the skin and mucosa. Infection by a high-risk (oncogenic) anogenital HPV type, most often through sexual contacts, is the starting point of virtually all cases of cervical cancers and the majority of anal cancers. The same viral types are also increasingly being linked with a subset of head-and-neck and non-melanoma skin cancers. Although prophylactic vaccines are now available to protect against the four types most commonly found in cervical and anal cancers (HPV16 and HPV18) and anogenital warts (HPV6 and HPV11), these neither protect against all genital HPVs nor are of therapeutic utility for already infected patients. Thus, the need for antiviral agents to treat HPV-associated diseases remains great, but none currently exist. This article reviews the recent progress made towards the development of antiviral agents to treat HPV infections, from target identification and validation to the discovery of lead compounds with therapeutic potential. Emphasis has been placed on novel low-molecular-weight compounds that antagonize HPV proteins or, alternatively, inhibit cellular proteins which have been usurped by papillomaviruses and are mediating their pathogenic effects.
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Affiliation(s)
- Amélie Fradet-Turcotte
- Laboratory of Molecular Virology, Institut de Recherches Cliniques de Montréal, Montreal, Quebec, Canada
- Department of Biochemistry, University of Montreal, Montreal, Quebec, Canada
| | - Jacques Archambault
- Laboratory of Molecular Virology, Institut de Recherches Cliniques de Montréal, Montreal, Quebec, Canada
- Department of Biochemistry, University of Montreal, Montreal, Quebec, Canada
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26
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Mistry N, Simonsson M, Evander M. Transcriptional activation of the human papillomavirus type 5 and 16 long control region in cells from cutaneous and mucosal origin. Virol J 2007; 4:27. [PMID: 17352804 PMCID: PMC1828153 DOI: 10.1186/1743-422x-4-27] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Accepted: 03/12/2007] [Indexed: 12/26/2022] Open
Abstract
Human papillomavirus type-16 (HPV-16) infects mucosal epithelium and is the most common type found in cervical cancer. HPV-5 infects cornified epithelium and is the most common type found on normal skin and belongs to the types frequently associated with skin cancers of Epidermodysplasia verruciformis patients. One factor by which this anatomical tropism could be determined is the regulation of HPV gene expression in the host cell. The HPV long control region (LCR) contains cis-responsive elements that regulate HPV transcription and the epithelial tropism of HPV is determined by epithelial specific constitutive enhancers in the LCR. Since HPV-16 and other types infecting the mucosa differ in host cell from HPV types infecting skin, it has been hypothesized that it is the combination of ubiquitous transcription factors working in concert in the host cell that determines the cell-type-specific expression. To study if HPV tropism could be determined by differences in transcriptional regulation we have cloned the transcriptional regulating region, LCR, from HPV-16 and HPV-5 and studied the activation of a reporter gene in cell lines with different origin. To analyse promoter activity we transfected the plasmids into four different cell lines; HaCaT, C33A, NIKS and W12E and the efficiency of HPV-5 and HPV-16 LCR in the different cell lines was compared. In HaCaT cells, with a skin origin, the HPV-5 LCR was two-fold more efficient in transcriptional activation compared to the HPV-16 LCR. In cervical W12E cells the HPV-16 LCR was almost 2-fold more effective in activating transcription compared to the HPV-5 LCR. The ability to initiate transcription in the other cell lines was independent on cell origin and HPV-type.
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Affiliation(s)
- Nitesh Mistry
- Department of Virology, Umeå University, S-901 85 Umeå, Sweden
| | | | - Magnus Evander
- Department of Virology, Umeå University, S-901 85 Umeå, Sweden
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27
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Fradet-Turcotte A, Archambault J. Recent advances in the search for antiviral agents against human papillomaviruses. Antivir Ther 2007; 12:431-51. [PMID: 17668552 PMCID: PMC4646640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Infection by human papillomavirus (HPV) is extremely common and associated with the development of benign warts or malignant lesions of the skin and mucosa. Infection by a high-risk (oncogenic) anogenital HPV type, most often through sexual contacts, is the starting point of virtually all cases of cervical cancers and the majority of anal cancers. The same viral types are also increasingly being linked with a subset of head-and-neck and non-melanoma skin cancers. Although prophylactic vaccines are now available to protect against the four types most commonly found in cervical and anal cancers (HPV16 and HPV18) and anogenital warts (HPV6 and HPV11), these neither protect against all genital HPVs nor are of therapeutic utility for already infected patients. Thus, the need for antiviral agents to treat HPV-associated diseases remains great, but none currently exist. This article reviews the recent progress made towards the development of antiviral agents to treat HPV infections, from target identification and validation to the discovery of lead compounds with therapeutic potential. Emphasis has been placed on novel low-molecular-weight compounds that antagonize HPV proteins or, alternatively, inhibit cellular proteins which have been usurped by papillomaviruses and are mediating their pathogenic effects.
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Affiliation(s)
- Amélie Fradet-Turcotte
- Laboratory of Molecular Virology, Institut de Recherches Cliniques de Montréal, Montreal, Quebec, Canada
- Department of Biochemistry, University of Montreal, Montreal, Quebec, Canada
| | - Jacques Archambault
- Laboratory of Molecular Virology, Institut de Recherches Cliniques de Montréal, Montreal, Quebec, Canada
- Department of Biochemistry, University of Montreal, Montreal, Quebec, Canada
- Corresponding author: Tel: +1 514 987 5739; Fax: +1 514 987 5741;
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28
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Chen Z, Schiffman M, Herrero R, DeSalle R, Burk RD. Human papillomavirus (HPV) types 101 and 103 isolated from cervicovaginal cells lack an E6 open reading frame (ORF) and are related to gamma-papillomaviruses. Virology 2006; 360:447-53. [PMID: 17125811 PMCID: PMC1885239 DOI: 10.1016/j.virol.2006.10.022] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2006] [Revised: 09/20/2006] [Accepted: 10/13/2006] [Indexed: 11/26/2022]
Abstract
Complete genomes of HPV101 and HPV103 were PCR amplified and cloned from cervicovaginal cells of a 34-year-old female with cervical intraepithelial neoplasia grade 3 (CIN 3) and a 30-year-old female with a normal Pap test, respectively. HPV101 and HPV103 contain 4 early genes (E7, E1, E2, and E4) and 2 late genes (L2 and L1), but both lack the canonical E6 ORF. Pairwise alignment similarity of the L1 ORF nucleotide sequences of HPV101 and HPV103 indicated that they are at least 30% dissimilar to each other and all known PVs. However, similarities of the other ORFs (E7, E1, E2, and L2) indicated that HPV101 and HPV103 are most related to each other. Phylogenetic analyses revealed that these two types form a monophyletic clade, clustering together with the gamma- and pi-PV groups. These data demonstrated that HPV genomes closely related to papillomaviruses identified from cutaneous epithelia can be isolated from the genital mucosal region. Moreover, this is the first report of HPVs lacking an E6 ORF and phylogenetic evidence suggests this occurred subsequent to their emergence from the gamma-/pi-PVs.
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Affiliation(s)
- Zigui Chen
- Department of Microbiology & Immunology, Albert Einstein Cancer Center, Albert Einstein College of Medicine of Yeshiva University, New York, 10461, USA
| | - Mark Schiffman
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, US Department of Health and Human Services, Bethesda, Maryland, USA
| | - Rolando Herrero
- Proyecto Epidemiológico Guanacaste, Costa Rican Foundation for Health Sciences, San José, Costa Rica
| | - Rob DeSalle
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024, USA
| | - Robert D. Burk
- Department of Microbiology & Immunology, Albert Einstein Cancer Center, Albert Einstein College of Medicine of Yeshiva University, New York, 10461, USA
- Department of Pediatrics, Epidemiology & Population Health and Obstetrics, Gynecology & Woman’s Health, Albert Einstein Cancer Center, Albert Einstein College of Medicine of Yeshiva University, New York, 10461, USA
- * Correspondence author: Robert D. Burk, MD, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, 10461, USA, TEL: 718-430-3720, FAX: 718-430-8975, E-mail:
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29
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Carson A, Khan SA. Characterization of transcription factor binding to human papillomavirus type 16 DNA during cellular differentiation. J Virol 2006; 80:4356-62. [PMID: 16611894 PMCID: PMC1472023 DOI: 10.1128/jvi.80.9.4356-4362.2006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human papillomaviruses (HPVs) require terminal differentiation of the host cell to produce infectious virions. The process of viral maturation involves a variety of changes in the expression/activity of host proteins that lead to high-level replication of the viral genome and expression of the late viral genes. Although the late promoter regions of HPV type 16 (HPV-16) are still not fully characterized, differentiation-dependent regulation of viral genes is thought to involve changes in the binding of host cell transcription factors to the viral promoter and regulatory regions. Currently, very little is known about specific cellular transcription factors involved in this process. We used the Panomics TransSignal protein/DNA array to identify changes in the levels of cellular transcription factors during methylcellulose-induced differentiation of W12 (20863) cells containing HPV-16. We then identified the differentially expressed transcription factors that specifically bind to HPV-16 DNA, including the known promoter and regulatory regions. We have validated the results obtained from the Panomics array by Western blot analysis. Furthermore, by chromatin immunoprecipitation assays, we have shown that many of the transcription factors identified in the above screen bind to the HPV-16 promoter/regulatory sequences in vivo and that the level of this binding is increased during differentiation. This approach identified approximately 30 transcription factors that specifically bind to HPV-16 sequences and may be involved in regulating HPV-16 transcription during differentiation. Although some of these transcription factors have previously been suggested to be involved in HPV-16 transcription, a number of them represent novel viral DNA-host protein interactions.
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Affiliation(s)
- Andrew Carson
- Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Room East 1240 Biomedical Science Tower, Pittsburgh, Pennsylvania 15261, USA
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Hubert WG. Variant upstream regulatory region sequences differentially regulate human papillomavirus type 16 DNA replication throughout the viral life cycle. J Virol 2005; 79:5914-22. [PMID: 15857977 PMCID: PMC1091712 DOI: 10.1128/jvi.79.10.5914-5922.2005] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
While the central role of the viral upstream regulatory region (URR) in the human papillomavirus (HPV) life cycle has been well established, its effects on viral replication factor expression and plasmid replication of HPV type 16 (HPV16) remain unclear. Some nonprototypic variants of HPV16 contain altered URR sequences and are considered to increase the oncogenic risk of infections. To determine the relationship between viral replication and variant URRs, hybrid viral genomes were constructed with the replication-competent HPV16 prototype W12 and analyzed in assays which recapitulate the different phases of normal viral replication. The establishment efficiencies of hybrid HPV16 genomes differed about 20-fold among European prototypes and variants from Africa and America. Generally, European and African genomes exhibited the lowest replication efficiencies. The high replication levels observed with American variants were primarily attributable to their efficient expression of the replication factors E1 and E2. The maintenance levels of these viral genomes varied about fivefold, which correlated with their respective establishment phenotypes and published P(97) activities. Vegetative DNA amplification could also be observed with replicating HPV16 genomes. These results indicate that efficient E1/E2 expression and elevated plasmid replication levels during the persistent stage of infection may comprise a risk factor in HPV16-mediated oncogenesis.
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Affiliation(s)
- Walter G Hubert
- Department of Dermatology, MS576, University of Arkansas for Medical Sciences, 4301 W. Markham St., Little Rock, AR 72205, USA.
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Glahder JA, Hansen CN, Vinther J, Madsen BS, Norrild B. A promoter within the E6 ORF of human papillomavirus type 16 contributes to the expression of the E7 oncoprotein from a monocistronic mRNA. J Gen Virol 2004; 84:3429-3441. [PMID: 14645924 DOI: 10.1099/vir.0.19250-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human papillomavirus type 16 (HPV-16) has the capacity to transform human primary keratinocytes. Maintenance of the transformed phenotype requires constitutive expression of the oncoproteins E6 and E7. The low-risk HPV types express E7 from monocistronic mRNA, but for the high-risk types, no mRNA that encodes E7 as the first open reading frame (ORF) has been identified. We recently identified a transcription initiation site within the E6 ORF of HPV-16 at nt 542. In the present study we have characterized the P542 promoter, which putatively controls monocistronic expression of E7. The monocistronic mRNA is not very abundant, but we have shown that an E7-luciferase fusion protein can be expressed in SiHa cells from a monocistronic HPV-16 transcript initiated at nt 542. The monocistronic mRNA expresses E7-luciferase more efficiently than the most abundant in vivo-like mRNA E6*IE7, initiated by P97 and spliced from nt 226 to 409. Furthermore, the translation initiation of E7 is most abundant from the monocistronic mRNA. We have also shown that the P542 promoter is downregulated by the transcription factor activator protein 4 (AP-4) and the differentiation-dependent factor hSkn-1a, both binding downstream of the transcription initiation site. In conclusion, we have found that P542 is a relatively weak promoter compared with P97 and may be downregulated in differentiated epithelial cells.
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Affiliation(s)
- Jacob A Glahder
- The DNA Tumour Virus Group, Institute of Molecular Pathology, The Protein Laboratory, University of Copenhagen, Panum Institute, Bldg 6.2, Blegdamsvej 3C, DK-2200 Copenhagen N, Denmark
| | - Christina N Hansen
- The DNA Tumour Virus Group, Institute of Molecular Pathology, The Protein Laboratory, University of Copenhagen, Panum Institute, Bldg 6.2, Blegdamsvej 3C, DK-2200 Copenhagen N, Denmark
| | - Jeppe Vinther
- The DNA Tumour Virus Group, Institute of Molecular Pathology, The Protein Laboratory, University of Copenhagen, Panum Institute, Bldg 6.2, Blegdamsvej 3C, DK-2200 Copenhagen N, Denmark
| | - Birger S Madsen
- The DNA Tumour Virus Group, Institute of Molecular Pathology, The Protein Laboratory, University of Copenhagen, Panum Institute, Bldg 6.2, Blegdamsvej 3C, DK-2200 Copenhagen N, Denmark
| | - Bodil Norrild
- The DNA Tumour Virus Group, Institute of Molecular Pathology, The Protein Laboratory, University of Copenhagen, Panum Institute, Bldg 6.2, Blegdamsvej 3C, DK-2200 Copenhagen N, Denmark
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Kang HT, Ju JW, Cho JW, Hwang ES. Down-regulation of Sp1 Activity through Modulation of O-Glycosylation by Treatment with a Low Glucose Mimetic, 2-Deoxyglucose. J Biol Chem 2003; 278:51223-31. [PMID: 14532290 DOI: 10.1074/jbc.m307332200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
2-Deoxyglucose (2-DG), a nonmetabolizable glucose analogue, blocks glycolysis at the phosphohexose isomerase step and has been frequently used as a glucose starvation mimetic in studies of a wide variety of physiological dysfuctions. However, the effect of 2-DG on protein glycosylation and related signal pathways has not been investigated in depth. In HeLa, an HPV18-positive cervical carcinoma line, 2-DG treatment down-regulates human papillomavirus early gene transcription. This down-regulation was also achieved by low glucose supply or hypoxia, suggesting that this is a response commonly modulated by cellular glucose or energy level. We investigated how 2-DG and low glucose affect transcriptional activity. Human papillomavirus gene transcription was only marginally affected by the inhibition of ATP synthesis or the supplementation of pyruvate to 2-DG-treated cells, suggesting that poor ATP generation is involved only to a limited extent. 2-DG treatment also inhibited activation of p21 WAF1 promoter, which is controlled by p53 and/or Sp1. In a reporter assay using p21 WAF1 promoter constructs, 2-DG exerted a strong inhibitory effect on Sp1 activity. DNA binding activity of Sp1 in 2-DG-treated HeLa cells was intact, whereas it was severely impaired in cells incubated in a low glucose medium or in hypoxic condition. Unexpectedly, Sp1 was heavily modified with GlcNAc in 2-DG-treated cells, which is at least partially attributed to the inhibitory effect of 2-DG on N-acetyl-beta-D-glucosaminidase activity. Our results suggest that 2-DG, like low glucose or hypoxic condition, down-regulates Sp1 activity, but through hyper-GlcNAcylation instead of hypo-GlcNAcylation.
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Affiliation(s)
- Hyun Tae Kang
- Department of Life Science, University of Seoul, Seoul 130-743, Korea
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Terai M, Burk RD. Felis domesticus papillomavirus, isolated from a skin lesion, is related to canine oral papillomavirus and contains a 1.3 kb non-coding region between the E2 and L2 open reading frames. J Gen Virol 2002; 83:2303-2307. [PMID: 12185286 DOI: 10.1099/0022-1317-83-9-2303] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We have characterized the complete genome (8300 bp) of an isolate of Felis domesticus papillomavirus (FdPV) from a domestic cat with cutaneous papillomatosis. A BLAST homology search using the nucleotide sequence of the L1 open reading frame demonstrated that the FdPV genome was most closely related to canine oral papillomavirus (COPV). A 384 bp non-coding region (NCR) was found between the end of L1 and the beginning of E6, and a 1.3 kbp NCR was located between the end of E2 and the beginning of L2. Phylogenetic analysis placed FdPV in the E3 clade with COPV. Both viruses contain the atypical second NCR, which has no homology with sequences in existing databases.
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Affiliation(s)
- Masanori Terai
- Department of Microbiology & Immunology1, and Departments of Pediatrics, Obstetrics & Gynecology and Women's Health, and Epidemiology & Social Medicine2, Comprehensive Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Robert D Burk
- Department of Microbiology & Immunology1, and Departments of Pediatrics, Obstetrics & Gynecology and Women's Health, and Epidemiology & Social Medicine2, Comprehensive Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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Bernard HU. Gene Expression of Genital Human Papillomaviruses and Considerations on Potential Antiviral Approaches. Antivir Ther 2002. [DOI: 10.1177/135965350200700401] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Genital human papillomaviruses (HPVs) are carcinogenic to humans and are associated with most cases of cervical cancer, genital and laryngeal warts, and certain cutaneous neoplastic lesions. Five of the more than 50 known genital HPV types, HPV-6, -11, -16, -18 and -31, have become the models to study gene expression. The comparison of the studies of these five viruses and analyses of the genomic sequences of those genital HPV types that have not been transcriptionally studied make it likely that genital HPVs share most strategies for regulating their transcription. These strategies are quite different from those of unrelated human and animal papillomaviruses. Among these common properties are (i) a specific promoter structure allowing for fine-tuned negative feedback, (ii) a transcriptional enhancer that is specific for epithelial cells, (iii) regulation by progesterone and glucocorticoid hormones, (iv) silencers, whose principal function appears to be transcriptional repression in the basal layer of infected epithelia, (v) specifically positioned nucleosomes that mediate the functions of some enhancer and the silencer factors, (vi) nuclear matrix attachment regions that can, under different conditions, repress or stimulate transcription, and (vii) as yet poorly understood late promoters positioned very remote from the late genes. Most of these properties are controlled by cellular proteins that, due to their simultaneous importance for cellular processes, may not be useful as HPV-specific drug targets. It should be possible, however, to target complex cis-responsive elements unique to these HPV genomes by nucleotide sequence-specific molecules, such as antisense RNA, polyamides and artificial transcription factors. The application of small molecule-based drugs may be restricted to target proteins encoded by the HPV DNA, such as the replication factor E1 and the transcription/replication factor E2.
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Terai M, Burk RD. Characterization of a novel genital human papillomavirus by overlapping PCR: candHPV86 identified in cervicovaginal cells of a woman with cervical neoplasia. J Gen Virol 2001; 82:2035-2040. [PMID: 11514712 DOI: 10.1099/0022-1317-82-9-2035] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A novel human papillomavirus (HPV), candHPV86, was cloned and characterized from cervicovaginal cells obtained from a 37-year-old Hispanic woman with cervical intraepithelial neoplasia grade 1 (CIN1) using an overlapping PCR technique. Primers were designed by phylogenetic alignment of closely related HPV genomes using the L1 fragment sequence amplified by GP5+/6+. The 7983 bp complete nucleotide sequence of the HPV genome was determined by sequence walking. A basic local alignment sequence tool (BLAST) homology search using the L1 open reading frame demonstrated that this HPV was most closely related to HPVHAN2294 (GenBank, AJ400628; 86% homology) and HPV84 (84% homology). candHPV86 was placed in the HPV genome homology group A3 by phylogenetic analyses. The overlapping PCR technique is applicable for characterizing the complete spectrum and variation of HPVs in a population.
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Affiliation(s)
- Masanori Terai
- Departments of Microbiology & Immunology1, Pediatrics, and Epidemiology & Social Medicine2, Comprehensive Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, 10461, USA
| | - Robert D Burk
- Departments of Microbiology & Immunology1, Pediatrics, and Epidemiology & Social Medicine2, Comprehensive Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, 10461, USA
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Newhouse CD, Silverstein SJ. Orientation of a novel DNA binding site affects human papillomavirus-mediated transcription and replication. J Virol 2001; 75:1722-35. [PMID: 11160670 PMCID: PMC114081 DOI: 10.1128/jvi.75.4.1722-1735.2001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
A consensus binding site for the human papillomavirus (HPV) E2 protein was determined from an unbiased set of degenerate oligonucleotides using cyclic amplification and selection of targets (CASTing). Detectable DNA-protein complexes were formed after six to nine cycles of CASTing. A population of selected binding sites was cloned, and a consensus was determined by statistical analysis of the DNA sequences of individual isolates. Starting from a pool with 20 random bases, a consensus binding site of ACAC-N(5)-GGT was derived. CASTing and electrophoretic mobility shift analyses demonstrate that human but not bovine papillomavirus E2 proteins recognize this sequence. The presence of this sequence in papillomavirus genomes suggests a role for its function. We demonstrate that this site functionally substitutes for the canonical E2 binding site (ACCG-N(4)-CGGT) in both transient-transcription and DNA replication assays. This sequence, in most instances, is interchangeable with the resident E2 binding sites in the context of the HPV type 16 long control region. Where the novel sequence does not support E2-mediated effects on gene expression or DNA replication, we demonstrate that changing the orientation of the novel sequence restores this effect.
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Affiliation(s)
- C D Newhouse
- Integrated Program in Cellular, Molecular and Biophysical Studies, Columbia University, New York, New York 10032, USA
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37
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Terai M, Burk RD. Complete nucleotide sequence and analysis of a novel human papillomavirus (HPV 84) genome cloned by an overlapping PCR method. Virology 2001; 279:109-15. [PMID: 11145894 DOI: 10.1006/viro.2000.0716] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Molecular diagnosis of human papillomaviruses (HPVs) in cervicovaginal samples reveals a plethora of known and novel HPV genomes. We describe the use of an overlapping PCR method to clone and analyze the complete genome of HPV 84 from cervicovaginal cells obtained from a 21-year-old Caucasian female with a normal Pap smear. The 7948-bp complete nucleotide sequence of HPV 84 was determined from five overlapping PCR products by sequence walking. A BLAST homology search demonstrated that HPV 84 was most closely related to HPV 61 (89%), HPV 72 (86%), and HPV 83 (85%) by nucleotide sequence analysis of the L1 open reading frame, placing it in the HPV genome homology group A3. Previously, this virus had been identified as Pap155. Based on extensive epidemiological data, HPV 84 is a highly prevalent genital papillomavirus primarily detected in normal and HIV-infected women.
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Affiliation(s)
- M Terai
- Department of Microbiology and Immunology, Comprehensive Cancer Center, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, 10461, USA
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38
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Affiliation(s)
- Masanori Terai
- Department of Microbiology & Immunology, Comprehensive Cancer Center, Albert Einstein College of Medicine
- Molecular Pathology, Oral Restitution, Oral Health Science, Graduate School, Tokyo Medical and Dental University
| | - Minoru Takagi
- Molecular Pathology, Oral Restitution, Oral Health Science, Graduate School, Tokyo Medical and Dental University
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39
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Kurvinen K, Yliskoski M, Saarikoski S, Syrjänen K, Syrjänen S. Variants of the long control region of human papillomavirus type 16. Eur J Cancer 2000; 36:1402-10. [PMID: 10899654 DOI: 10.1016/s0959-8049(00)00121-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Expression of the human papillomavirus (HPV) E6 and E7 oncogenes is regulated on the transcriptional level by specific protein-binding sites contained in the viral long control region (LCR). Sequence changes within the LCR region may have an impact on the transcription of viral oncogenes, possibly resulting in differences in the oncogenic potential of the virus. The present study was designed to determine the sequence variability of the LCR of HPV 16 and to assess whether certain LCR variants do correlate with the clinical outcome of the disease of the uterine cervix. The entire LCR segment of HPV 16 was analysed from 37 cervical biopsy specimens derived from 28 women included in the Kuopio long-term prospective follow-up study. The LCR sequence was identical with the reference sequence in six HPV 16 isolates. Overall, 14 different HPV 16 LCR variants were identified. One of the variants showed sequence variation typical of the Asian-American variant lineage of HPV 16, and all the other variants appeared to belong to the European variant group. The European variants exhibited low genetic diversity, and only five of these LCR variants contained nucleotide changes involving known or proposed binding sites for transcription factors. The variants with changes at nucleotide positions 7193 and 7521 was the most prevalent, accounting for almost 37% of infections. This variant (7193; 7521) has been previously demonstrated to have similar transcriptional activity compared with the reference isolate by Veress and colleagues J Gen Virol 1999, 80, 1035-1043. The reference isolate, variant (7193; 7521) and variants with changes within transcription factor binding sites accounted for most of the infections, and no significant differences were found in the comparison of the distribution of these different LCR isolates in cases where the disease showed progression to severe cervical intraepithelial neoplasia (CIN) or carcinoma in situ (CIS). Notably, both the reference isolate and variant (7193; 7521) were also closely associated with infections showing more aggressive behaviour. According to the present findings, in European HPV 16 isolates, intratype genetic variation of the LCR region does not seem to be commonly responsible for differences in the pathogenicity of the virus and thereby for a risk of progressive infections.
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Affiliation(s)
- K Kurvinen
- MediCity Research Laboratory, Faculty of Medicine, University of Turku, Tykistökatu 6 A, FIN-20520, Turku, Finland
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Craigo J, Callahan M, Huang RC, DeLucia AL. Inhibition of human papillomavirus type 16 gene expression by nordihydroguaiaretic acid plant lignan derivatives. Antiviral Res 2000; 47:19-28. [PMID: 10930643 DOI: 10.1016/s0166-3542(00)00089-9] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Several methylated derivatives of a plant lignan, nordihydroguaiaretic acid (NDGA) were found to be potent anti-viral agents by suppressing Sp1 regulated transcription within the sexually transmitted viruses human immunodeficiency virus (HIV) and herpes simplex virus (HSV). A prominent Sp1 DNA binding site within many human papillomavirus (HPV) promoters has been noted to play an active role in HPV gene expression. In this report it is shown that the three NDGA derivatives, Mal.4, M(4)N, and tetra-acetyl NDGA can also inhibit gene expression from the early promoter P(97) of HPV16. The drug activity on gene expression was measured after DNA transfection of recombinant vector constructs linking the viral promoter and enhancer elements to the luciferase reporter gene. Using the specific luciferase activity as the indicator of gene expression, Mal.4 and M(4)N were found to be active in a dose dependent manner that is in the same range of concentrations reported for the promoters of HIV, HSV, and simian virus 40 (SV40) while tetra-acetyl NDGA was much more active in suppression of the HPV P(97) promoter activity than Mal.4 and M(4)N. The drugs showed limited to no effect on gene expression driven by the adenovirus major late promoter and the cytomegalovirus (CMV) promoter. Hence, such drug derivatives may be significant in the therapy of papillomavirus infections and their associated induced human cancers.
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Affiliation(s)
- J Craigo
- Department of Microbiology and Immunology, Northeastern Ohio Universities College of Medicine, 4209 State RT 44, Rootstown, OH 44272, USA
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Abstract
Human papillomaviruses (HPVs) are common DNA viruses in humans. Recently, epithelial cancers associated with HPV infection have been used as models of virus-induced carcinogenesis. HPVs can be divided into two groups, mucosal and cutaneous. HPV-16 is the most frequent mucosal type associated with cervical cancer. Although the molecular mechanisms of carcinogenesis by HPV-16 have not been completely elucidated, it is apparent that HPV infection is the major risk factor in cervical carcinogenesis. Two viral early genes, E6 and E7, and an upstream regulatory region (URR) are preserved in cervical carcinoma cell lines as well as in clinical samples of cervical cancer, indicating that these regions are important in cancer development. E6 and E7 function as transforming genes. E6 protein binds to and promotes degradation of the tumor suppressor protein, p53, while E7 protein complexes and inactivates the Rb protein; together, they disrupt cell cycle regulation. E6 and E7 are transcribed from a promoter, P97. P97 is regulated by complex interactions between multiple, positive and negative, cellular factors and the viral E2 product. E2 disruption caused by the integration into the cellular genome may induce overexpression of E6 and E7. The E6 and E7 proteins are thought to act as critical factors in cervical carcinogenesis by inactivating the two tumor suppressor proteins, p53 and Rb, which are commonly mutated in other human cancers.
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Affiliation(s)
- T Ishiji
- Department of Dermatology, Jikei University School of Medicine, Tokyo, Japan
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Zhan D, Santin AD, Liu Y, Parham GP, Li C, Meyers C, Hermonat PL. Binding of the human papillomavirus type 16 p97 promoter by the adeno-associated virus Rep78 major regulatory protein correlates with inhibition. J Biol Chem 1999; 274:31619-24. [PMID: 10531369 DOI: 10.1074/jbc.274.44.31619] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human papillomavirus type 16 (HPV-16) infection is positively associated with cervical cancer, whereas adeno-associated virus (AAV) infection is negatively associated with this same cancer. In earlier studies these two virus types have been shown to directly interact, with AAV inhibiting or enhancing papillomavirus functions depending upon the specific circumstances. One defined interaction between these two viruses is the ability of the AAV Rep78 major regulatory protein to inhibit gene expression of the E6 promoter of BPV-1 (bovine papillomavirus type 1) and HPV types 16 and 18. As Rep78 is a DNA binding transcription factor, we considered whether Rep78 might bind HPV-16 DNA. Here, Rep78 is demonstrated to bind a 44-base pair region (nucleotides 14-56) within the HPV-16 p97 promoter using the electrophoretic mobility shift assay. This region is important for HPV-16 because it includes functional Sp1 and E2 protein binding motifs as well as part of the origin of replication. Furthermore, two Rep78 amino acid substitution mutants, at positions 77 or 64-65, were identified that did not recognize p97 DNA. Both of these Rep78 mutants were found to be defective for inhibition of p97 promoter activity in HeLa and T-47D nuclear extracts in vitro, in a transient chloramphenicol acetyltransferase assay, as well as defective for full inhibition of HPV-16-directed focus formation. These data, taken together, strongly suggest that the Rep78-p97 promoter interaction is at least partially responsible for Rep78-mediated inhibition of HPV-16. Finally, the finding that Rep78 specifically recognizes p97 DNA is surprising because the p97 promoter region contains no GAGC motifs, the core motif for Rep78 recognition. These data suggest that the p97 promoter may represent a new prototypical DNA target type for Rep78.
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Affiliation(s)
- D Zhan
- Department of Obstetrics and Gynecology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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Corden SA, Sant-Cassia LJ, Easton AJ, Morris AG. The integration of HPV-18 DNA in cervical carcinoma. Mol Pathol 1999; 52:275-82. [PMID: 10748877 PMCID: PMC395710 DOI: 10.1136/mp.52.5.275] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIMS Little information is available on the patterns of integration into the host chromosomal DNA of cervical carcinomas of human papillomavirus type 18 (HPV-18) DNA, which is associated with up to 20% of these carcinomas. Because integration of the viral genome may be extremely important in the pathogenesis of cervical carcinoma, the aim of this study was to investigate which regions of HPV-18 DNA are integrated into the cellular DNA of cervical carcinomas. METHODS Southern analysis using four subgenomic probes covering the entire HPV-18 genome was used to map viral DNA integrated within cellular DNA. The polymerase chain reaction (PCR) was used to confirm the presence of specific regions of the viral genome. RESULTS In all 11 carcinomas there was a single major HPV-18 DNA integrant, retaining approximately 4000 bp of HPV-18 DNA, indicating that approximately half of the virus genome had been lost upon integration. Southern analysis suggested strongly that the viral breakpoint was within the E1/E2 gene boundary, with concomitant loss of part or all of the E2 ORF (open reading frame), all of the E4, E5, and L2 ORFs and part of the L1 ORF. These data were supported by the PCR results, which confirmed that the region of integrated HPV-18 DNA from nucleotides 6558 to 162 was present in all the carcinoma samples studied. Assuming that no genomic rearrangements, deletions, or insertions had occurred, 4131 bp of integrated HPV-18 DNA could be accounted for in eight cervical carcinoma samples. The results of Southern analysis also suggested that integration of HPV-18 DNA may have occurred at a specific host chromosomal site. CONCLUSIONS Broadly, the viral sequences retained upon HPV-18 integration resemble those found when HPV-16 is integrated. However, it appears that the HPV-18 E2 region is more consistently deleted.
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Affiliation(s)
- S A Corden
- Department of Biological Sciences, University of Warwick, Coventry, UK
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44
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Vance KW, Campo MS, Morgan IM. An enhanced epithelial response of a papillomavirus promoter to transcriptional activators. J Biol Chem 1999; 274:27839-44. [PMID: 10488130 DOI: 10.1074/jbc.274.39.27839] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mucosal epitheliotropic papillomaviruses have a similar long control region (LCR) organization: a promoter region, an enhancer region, and a highly conserved distribution of E2 DNA binding sites. The enhancer of these viruses is epithelial-specific, as it fails to activate transcription from heterologous promoters in nonepithelial cell types (Gloss, B., Bernard, H. U., Seedorf, K., and Klock, G. (1987) EMBO J. 6, 3735-3743; Morgan, I. M., Grindlay, G. J., and Campo, M. S. (1999) J. Gen. Virol. 80, 23-27). Studies on E2 transcriptional regulation of the human mucosal epitheliotropic papillomaviruses have been hindered by poor access to the natural target cell type and by the observation that some of the human papillomavirus promoters, including human papillomavirus-16, are repressed in immortalized epithelial cells. Here we present results using the bovine papillomavirus-4 (BPV-4) LCR and a bovine primary cell system as a model to study the mechanism of E2 transcriptional regulation of mucosal epitheliotropic papillomaviruses and the cell type specificity of this regulation. E2 up-regulates transcription from the BPV-4 LCR preferentially in epithelial cells (Morgan, I. M., Grindlay, G. J., and Campo, M. S. (1998) J. Gen. Virol. 79, 501-508). We demonstrate that the epithelial-specific enhancer element of the BPV-4 LCR is not required for the enhanced activity of E2 in epithelial cells and that the BPV-4 promoter is more responsive, not only to E2, but to other transcriptional activators in epithelial cells. This is the first time a level of epithelial specificity has been shown to reside in a papillomavirus promoter region.
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Affiliation(s)
- K W Vance
- Beatson Institute for Cancer Research, Cancer Research Campaign Beatson Laboratories, Garscube Estate, Glasgow G61 1BD, Scotland
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45
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Dong XP, Pfister H. Overlapping YY1- and aberrant SP1-binding sites proximal to the early promoter of human papillomavirus type 16. J Gen Virol 1999; 80 ( Pt 8):2097-2101. [PMID: 10466808 DOI: 10.1099/0022-1317-80-8-2097] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Transcription of oncogenes E6 and E7 of human papillomavirus type 16 (HPV-16) from the P97 promoter is regulated by viral and cellular proteins. The transcription factor YY1 represses transcription through binding to cognate sequences in the long control region (LCR). In HPV-16 DNA from cervical carcinomas, mutations of YY1-binding sites have been identified that increase P97 activity 3-6-fold. A second, SP1-binding site has now been identified in the HPV-16 LCR (nt 7842-7847), which overlaps the YY1-binding site at positions 7840-7848. A point mutation within this YY1 site in viral DNA from a cervical cancer, previously shown to prevent YY1 binding, was shown to increase SP1 binding and P97 activity 4.7-fold. An engineered mutant eliminating SP1 binding showed only 1- to 1.6-fold increased P97 activity. It is concluded that competition between SP1 and YY1 for DNA binding plays a major role in YY1 repression mediated by the binding site at positions 7840-7848.
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Affiliation(s)
- Xiao-Ping Dong
- Institute of Virology, Universität zu Köln, Fürst-Pückler Str. 56, 50935 Köln, Germany1
| | - Herbert Pfister
- Institute of Virology, Universität zu Köln, Fürst-Pückler Str. 56, 50935 Köln, Germany1
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Lewis H, Webster K, Sanchez-Perez AM, Gaston K. Cellular transcription factors regulate human papillomavirus type 16 gene expression by binding to a subset of the DNA sequences recognized by the viral E2 protein. J Gen Virol 1999; 80 ( Pt 8):2087-2096. [PMID: 10466807 DOI: 10.1099/0022-1317-80-8-2087] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human papillomavirus type 16 (HPV-16) is a DNA tumour virus that has been implicated in the development of cervical cancer. The HPV-16 E2 protein binds to four sites that are present upstream of the viral P97 promoter and regulates transcription of the E6 and E7 oncogenes. Here, it is shown that cellular transcription factors bind to two of these E2 sites. One cellular E2 site-binding factor, which is here named CEF-1, binds tightly to E2 site 1. CEF-2, an unrelated cellular E2 site-binding factor, binds tightly to E2 site 3. Transient transfection studies performed in the absence of the E2 protein showed that mutations that blocked the binding of CEF-1 to E2 site 1 or CEF-2 to E2 site 3 significantly reduced P97 promoter activity. Further characterization of CEF-1 indicated that this factor has not previously been identified and that CEF-1 and E2 competed for binding at E2 site 1.
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Affiliation(s)
- Hannah Lewis
- Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK1
| | - Kenneth Webster
- Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK1
| | - Ana-Maria Sanchez-Perez
- Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK1
| | - Kevin Gaston
- Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK1
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O'Connor MJ, Stünkel W, Zimmermann H, Koh CH, Bernard HU. A novel YY1-independent silencer represses the activity of the human papillomavirus type 16 enhancer. J Virol 1998; 72:10083-92. [PMID: 9811748 PMCID: PMC110540 DOI: 10.1128/jvi.72.12.10083-10092.1998] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Regulation of the human papillomavirus type 16 (HPV-16) E6 promoter is a complex process in which transcriptional repression as well as activation plays an important role. Here, we identify a negative regulatory element that in the context of a continuous long control region fragment overcomes the activation of the HPV-16 enhancer. This silencing element, which we have termed a PSM (papillomavirus silencing motif), consists of two copies of the sequence 5'-TAYAATAAT-3' that overlap the origin of replication. Each copy of this 9-bp sequence binds the same unknown cellular factor, which we refer to as PSM-BP (PSM binding protein). Both copies of the binding sequence are required for transcriptional repression, and we provide evidence that suggests that this particular organization results in the stabilization of a PSM-BP dimer. The silencing motif, while functioning in either orientation, showed a positional requirement between the enhancer and the promoter. Experiments with both a heterologous enhancer and a promoter also demonstrated a general ability of this element to function as a transcriptional silencer in non-HPV systems. Our findings provide an important addition to our understanding of HPV-16 gene regulation and an interesting model for the study of transcriptional repression.
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Affiliation(s)
- M J O'Connor
- Institute of Molecular and Cell Biology, Singapore 117 609, Singapore
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Ozbun MA, Meyers C. Temporal usage of multiple promoters during the life cycle of human papillomavirus type 31b. J Virol 1998; 72:2715-22. [PMID: 9525589 PMCID: PMC109714 DOI: 10.1128/jvi.72.4.2715-2722.1998] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The life cycles of human papillomaviruses (HPVs) are dependent upon the differentiation of the epithelial cells they infect. HPV type 31b (HPV31b) virions can be purified following the growth of a latently HPV-infected cell line (CIN-612 9E) in the organotypic or raft system. Treatment of the CIN-612 9E raft tissues with protein kinase C (PKC) activators is required for upregulation of late gene expression and efficient production of virions. We employed the raft culture system to study the temporal usage of HPV31b promoters during the viral life cycle. We compared monolayer cultures of CIN-612 9E cells, untreated CIN-612 9E raft tissues, and PKC-induced CIN-612 9E raft tissues harvested at various time points during epithelial differentiation. We found that the HPV31b major early promoter precisely maps to nucleotide (nt) 99 (P99). A transcriptional start site for both early and late gene transcripts mapped upstream of P99 at nt 77 (P77). The P77 and P99 promoters were used constitutively throughout the HPV31b life cycle; however, initiation from P99 was much stronger than from P77. Mapping of the differentiation-induced P742 promoter revealed multiple start sites. These start sites were difficult to detect in monolayer cultures, were induced in untreated rafts, and were greatest in PKC-induced raft tissues at 8 to 12 days. A constitutively active promoter, P3320, was also defined and is responsible for the transcription of unspliced and spliced RNAs containing E5a, E5b, L2, and L1 open reading frames.
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Affiliation(s)
- M A Ozbun
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey 17033, USA
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Bauknecht T, Shi Y. Overexpression of C/EBPbeta represses human papillomavirus type 18 upstream regulatory region activity in HeLa cells by interfering with the binding of TATA-binding protein. J Virol 1998; 72:2113-24. [PMID: 9499067 PMCID: PMC109506 DOI: 10.1128/jvi.72.3.2113-2124.1998] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The human papillomavirus type 18 (HPV-18) upstream regulatory region (URR) controls cell type-specific expression of viral oncoproteins E6 and E7. The HPV-18 URR is highly active in HeLa cells, but its activity is virtually undetectable in HepG2 cells. Previous work has shown that YY1 plays an important role in activation of the HPV-18 URR in HeLa cells, and this activating activity is dependent on its physical interaction with C/EBPbeta, which binds to the switch region adjacent to the YY1 site in the URR. Overexpression of C/EBPbeta in HepG2 cells restores C/EBPbeta-YY1 interaction, resulting in strong activation of the HPV-18 URR activity. In this report, we show that, in contrast to the effect in HepG2 cells, overexpression of C/EBPbeta represses the HPV-18 URR in HeLa cells. This C/EBPbeta-induced repression of the HPV-18 URR in HeLa cells is binding site independent. It is also promoter specific, since it activates the albumin promoter under conditions in which it represses the URR in the same cells. Biochemical analysis shows that overexpression of C/EBPbeta in HeLa cells specifically interferes with binding of TATA-binding protein to the TATA box of the HPV-18 URR, but its overexpression in HepG2 cells leads to activation of the HPV-18 URR. These results suggest that a molecular mechanism underlies the ability of C/EBPbeta to regulate transcription in a cell type-specific manner and indicate the potential of using C/EBPbeta to manipulate the activity of the HPV-18 URR in cervical carcinoma cells.
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Affiliation(s)
- T Bauknecht
- Forschungsschwerpunkt Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum Heidelberg, Germany.
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Demeret C, Desaintes C, Yaniv M, Thierry F. Different mechanisms contribute to the E2-mediated transcriptional repression of human papillomavirus type 18 viral oncogenes. J Virol 1997; 71:9343-9. [PMID: 9371593 PMCID: PMC230237 DOI: 10.1128/jvi.71.12.9343-9349.1997] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Transcription of the human papillomavirus type 18 (HPV18) E6 and E7 oncogenes is repressed by the viral E2 protein. In C33 cells, we have previously shown that of the four E2 binding sites (E2 BS) present in the HPV18 long control region (LCR), only the binding site adjacent to the TATA box (E2 BS 1) was involved in E2-mediated repression. In the present study, we sought to determine whether this phenomenon was conserved in other cell lines. We first showed that all three E2 BS proximal to the P105 promoter were required for full repression of its activity in HeLa and HaCaT cells. Repression by E2 at E2 BS 2 occurred through the displacement of Sp1. Second, a truncated E2 product, lacking the N-terminal transactivation domain, repressed transcription more efficiently than the full-length protein. Repression was abolished when the N-terminal domain of E2 was replaced by the activation domain of VP16. The VP16-E2 chimeric protein could activate transcription from an LCR mutated in its TATA box. DNA-protein binding studies showed that E2 associates with its four binding sites in the LCR with similar affinities. However, challenge of such complexes with excess binding sites demonstrated that interaction with E2 BS 4 was the most stable while interaction with E2 BS 1 was the least stable. Furthermore, complexes with the full-length E2 were less stable than those formed with the N-terminally truncated protein.
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Affiliation(s)
- C Demeret
- Département des Biotechnologies, URA 1644 du CNRS, Institut Pasteur, Paris, France
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