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Xue S, Liu X, Liu Y, Lu C, Jia L, Yu Y, Liu H, Yang S, Zeng Z, Li H, Qin J, Wang Y, Sun J. Determination and Characterization of Novel Papillomavirus and Parvovirus Associated with Mass Mortality of Chinese Tongue Sole ( Cynoglossus semilaevis) in China. Viruses 2024; 16:705. [PMID: 38793587 PMCID: PMC11125579 DOI: 10.3390/v16050705] [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: 04/10/2024] [Revised: 04/28/2024] [Accepted: 04/28/2024] [Indexed: 05/26/2024] Open
Abstract
A massive mortality event concerning farmed Chinese tongue soles occurred in Tianjin, China, and the causative agent remains unknown. Here, a novel Cynoglossus semilaevis papillomavirus (CsPaV) and parvovirus (CsPV) were simultaneously isolated and identified from diseased fish via electron microscopy, virus isolation, genome sequencing, experimental challenges, and fluorescence in situ hybridization (FISH). Electron microscopy showed large numbers of virus particles present in the tissues of diseased fish. Viruses that were isolated and propagated in flounder gill cells (FG) induced typical cytopathic effects (CPE). The cumulative mortality of fish given intraperitoneal injections reached 100% at 7 dpi. The complete genomes of CsPaV and CsPV comprised 5939 bp and 3663 bp, respectively, and the genomes shared no nucleotide sequence similarities with other viruses. Phylogenetic analysis based on the L1 and NS1 protein sequences revealed that CsPaV and CsPV were novel members of the Papillomaviridae and Parvoviridae families. The FISH results showed positive signals in the spleen tissues of infected fish, and both viruses could co-infect single cells. This study represents the first report where novel papillomavirus and parvovirus are identified in farmed marine cultured fish, and it provides a basis for further studies on the prevention and treatment of emerging viral diseases.
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Affiliation(s)
- Shuxia Xue
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China; (S.X.); (X.L.); (Y.L.); (C.L.); (S.Y.); (Z.Z.); (H.L.); (J.Q.); (Y.W.)
| | - Xinrui Liu
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China; (S.X.); (X.L.); (Y.L.); (C.L.); (S.Y.); (Z.Z.); (H.L.); (J.Q.); (Y.W.)
| | - Yuru Liu
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China; (S.X.); (X.L.); (Y.L.); (C.L.); (S.Y.); (Z.Z.); (H.L.); (J.Q.); (Y.W.)
| | - Chang Lu
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China; (S.X.); (X.L.); (Y.L.); (C.L.); (S.Y.); (Z.Z.); (H.L.); (J.Q.); (Y.W.)
| | - Lei Jia
- Tianjin Fishery Institute, Tianjin 300221, China; (L.J.); (Y.Y.); (H.L.)
| | - Yanguang Yu
- Tianjin Fishery Institute, Tianjin 300221, China; (L.J.); (Y.Y.); (H.L.)
| | - Houfu Liu
- Tianjin Fishery Institute, Tianjin 300221, China; (L.J.); (Y.Y.); (H.L.)
| | - Siyu Yang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China; (S.X.); (X.L.); (Y.L.); (C.L.); (S.Y.); (Z.Z.); (H.L.); (J.Q.); (Y.W.)
| | - Zhu Zeng
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China; (S.X.); (X.L.); (Y.L.); (C.L.); (S.Y.); (Z.Z.); (H.L.); (J.Q.); (Y.W.)
| | - Hui Li
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China; (S.X.); (X.L.); (Y.L.); (C.L.); (S.Y.); (Z.Z.); (H.L.); (J.Q.); (Y.W.)
| | - Jiatong Qin
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China; (S.X.); (X.L.); (Y.L.); (C.L.); (S.Y.); (Z.Z.); (H.L.); (J.Q.); (Y.W.)
| | - Yuxuan Wang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China; (S.X.); (X.L.); (Y.L.); (C.L.); (S.Y.); (Z.Z.); (H.L.); (J.Q.); (Y.W.)
| | - Jinsheng Sun
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin 300387, China; (S.X.); (X.L.); (Y.L.); (C.L.); (S.Y.); (Z.Z.); (H.L.); (J.Q.); (Y.W.)
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Jasrotia R, Dhanjal DS, Bhardwaj S, Sharma P, Chopra C, Singh R, Kumar A, Mubayi A, Kumar D, Kumar R, Goyal A. Nanotechnology based vaccines: Cervical cancer management and perspectives. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2022.103351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Joo S, Chung BH, Lee M, Ha TH. Ring-shaped replicative helicase encircles double-stranded DNA during unwinding. Nucleic Acids Res 2020; 47:11344-11354. [PMID: 31665506 PMCID: PMC6868380 DOI: 10.1093/nar/gkz893] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/29/2019] [Accepted: 10/23/2019] [Indexed: 11/14/2022] Open
Abstract
Ring-shaped replicative helicases are hexameric and play a key role in cellular DNA replication. Despite their importance, our understanding of the unwinding mechanism of replicative helicases is far from perfect. Bovine papillomavirus E1 is one of the best-known model systems for replicative helicases. E1 is a multifunctional initiator that senses and melts the viral origin and unwinds DNA. Here, we study the unwinding mechanism of E1 at the single-molecule level using magnetic tweezers. The result reveals that E1 as a single hexamer is a poorly processive helicase with a low unwinding rate. Tension on the DNA strands impedes unwinding, indicating that the helicase interacts strongly with both DNA strands at the junction. While investigating the interaction at a high force (26–30 pN), we discovered that E1 encircles dsDNA. By comparing with the E1 construct without a DNA binding domain, we propose two possible encircling modes of E1 during active unwinding.
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Affiliation(s)
- Sihwa Joo
- BioNanoTechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea.,Department of Nanobiotechnology, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Bong H Chung
- BioNanoTechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea.,Department of Nanobiotechnology, University of Science and Technology (UST), Daejeon 34113, Republic of Korea.,BioNano Health Guard Research Center, Daejeon 34141, Republic of Korea
| | - Mina Lee
- Center for Nano-Bio Measurement, Korea Research Institute of Standards and Science, Daejeon 34113, Republic of Korea
| | - Tai H Ha
- BioNanoTechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea.,Department of Nanobiotechnology, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
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Garbuglia AR, Lapa D, Sias C, Capobianchi MR, Del Porto P. The Use of Both Therapeutic and Prophylactic Vaccines in the Therapy of Papillomavirus Disease. Front Immunol 2020; 11:188. [PMID: 32133000 PMCID: PMC7040023 DOI: 10.3389/fimmu.2020.00188] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/24/2020] [Indexed: 12/30/2022] Open
Abstract
Human papillomavirus (HPV) is the most common sexually transmitted virus. The high-risk HPV types (i.e., HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59) are considered to be the main etiological agents of genital tract cancers, such as cervical, vulvar, vaginal, penile, and anal cancers, and of a subset of head and neck cancers. Three prophylactic HPV vaccines are available that are bivalent (vs. HPV16, 18), tetravalent (vs. HPV6, 11, 16, 18), and non-avalent (vs. HPV6, 11, 16, 18, 31, 33,45, 52, 58). All of these vaccines are based on recombinant DNA technology, and they are prepared from the purified L1 protein that self-assembles to form the HPV type-specific empty shells (i.e., virus-like particles). These vaccines are highly immunogenic and induce specific antibodies. Therapeutic vaccines differ from prophylactic vaccines, as they are designed to generate cell-mediated immunity against transformed cells, rather than neutralizing antibodies. Among the HPV proteins, the E6 and E7 oncoproteins are considered almost ideal as targets for immunotherapy of cervical cancer, as they are essential for the onset and evolution of malignancy and are constitutively expressed in both premalignant and invasive lesions. Several strategies have been investigated for HPV therapeutic vaccines designed to enhance CD4+ and CD8+ T-cell responses, including genetic vaccines (i.e., DNA/ RNA/virus/ bacterial), and protein-based, peptide-based or dendritic-cell-based vaccines. However, no vaccine has yet been licensed for therapeutic use. Several studies have suggested that administration of prophylactic vaccines immediately after surgical treatment of CIN2 cervical lesions can be considered as an adjuvant to prevent reactivation or reinfection, and other studies have described the relevance of prophylactic vaccines in the management of genital warts. This review summarizes the leading features of therapeutic vaccines, which mainly target the early oncoproteins E6 and E7, and prophylactic vaccines, which are based on the L1 capsid protein. Through an analysis of the specific immunogenic properties of these two types of vaccines, we discuss why and how prophylactic vaccines can be effective in the treatment of HPV-related lesions and relapse.
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Affiliation(s)
- Anna Rosa Garbuglia
- Laboratory of Virology, "Lazzaro Spallanzani" National Institute for Infectious Diseases, IRCCS, Rome, Italy
| | - Daniele Lapa
- Laboratory of Virology, "Lazzaro Spallanzani" National Institute for Infectious Diseases, IRCCS, Rome, Italy
| | - Catia Sias
- Laboratory of Virology, "Lazzaro Spallanzani" National Institute for Infectious Diseases, IRCCS, Rome, Italy
| | - Maria Rosaria Capobianchi
- Laboratory of Virology, "Lazzaro Spallanzani" National Institute for Infectious Diseases, IRCCS, Rome, Italy
| | - Paola Del Porto
- Department of Biology and Biotechnology "C. Darwin," Sapienza University, Rome, Italy
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Hancock G, Blight J, Lopez-Camacho C, Kopycinski J, Pocock M, Byrne W, Price MJ, Kemlo P, Evans RI, Bloss A, Saunders K, Kirton R, Andersson M, Hellner K, Reyes-Sandoval A, Dorrell L. A multi-genotype therapeutic human papillomavirus vaccine elicits potent T cell responses to conserved regions of early proteins. Sci Rep 2019; 9:18713. [PMID: 31822717 PMCID: PMC6904585 DOI: 10.1038/s41598-019-55014-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/20/2019] [Indexed: 12/13/2022] Open
Abstract
Despite an efficacious prophylactic human papillomavirus (HPV) vaccine there is still a considerable global burden of HPV-related disease. Therapeutic vaccines that could prevent cancers in at-risk women are urgently needed. Most candidate therapeutic vaccines have focused on two high-risk (hr) HPV genotypes, 16 and 18, and two viral targets, E6 and E7, which may limit global coverage and efficacy. We designed the synthetic gene '5GHPV3' by selecting conserved regions from each of the six early proteins and generating consensus sequences to represent five hrHPV genotypes. 5GHPV3 was delivered by plasmid DNA, chimpanzee adenovirus (ChAdOx1) and modified vaccinia Ankara (MVA) vectors in prime-boost regimens to mice. ChAdOx1-5GHPV3 / MVA-5GHPV3 induced higher magnitude and more durable HPV-specific T cell responses than other regimens. Vaccine-induced T cells were polyfunctional and persisted at high frequencies for at least six weeks. Importantly, HPV-specific effector CD8 + T cells were detected in the cervix following systemic administration of ChAdOx1-5GHPV3 / MVA-5GHPV3 and increased in frequency over time, indicating continued trafficking of T cells to the cervix. Finally, T cells specific for 5GHPV3 encoded antigens were detected by IFN-γ Elispot in women with current or past hrHPV infections, confirming the presence of epitopes relevant to natural immune control.
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Affiliation(s)
- Gemma Hancock
- Nuffield Department of Medicine, University of Oxford and Oxford NIHR Biomedical Research Centre, NDM Research Building, Old Road Campus, Oxford, UK.
| | - Joshua Blight
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, The Henry Wellcome Building for Molecular Physiology, Roosevelt Drive, Oxford, UK
| | - Cesar Lopez-Camacho
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, The Henry Wellcome Building for Molecular Physiology, Roosevelt Drive, Oxford, UK
| | - Jakub Kopycinski
- Nuffield Department of Medicine, University of Oxford and Oxford NIHR Biomedical Research Centre, NDM Research Building, Old Road Campus, Oxford, UK
| | - Mamatha Pocock
- Nuffield Department of Medicine, University of Oxford and Oxford NIHR Biomedical Research Centre, NDM Research Building, Old Road Campus, Oxford, UK
| | - Wendy Byrne
- Direct Delivery Team, NIHR Clinical Research Network Thames Valley and South Midlands, Nuffield Orthopaedic Centre, Block 8, Oxford, OX3 7LD, UK
| | - Michael J Price
- Nuffield Department of Medicine, University of Oxford and Oxford NIHR Biomedical Research Centre, NDM Research Building, Old Road Campus, Oxford, UK
| | - Phillip Kemlo
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, The Henry Wellcome Building for Molecular Physiology, Roosevelt Drive, Oxford, UK
| | - Ranoromanana Ionitiana Evans
- Direct Delivery Team, NIHR Clinical Research Network Thames Valley and South Midlands, Nuffield Orthopaedic Centre, Block 8, Oxford, OX3 7LD, UK
| | - Angela Bloss
- Direct Delivery Team, NIHR Clinical Research Network Thames Valley and South Midlands, Nuffield Orthopaedic Centre, Block 8, Oxford, OX3 7LD, UK
| | - Kathryn Saunders
- Direct Delivery Team, NIHR Clinical Research Network Thames Valley and South Midlands, Nuffield Orthopaedic Centre, Block 8, Oxford, OX3 7LD, UK
| | - Richard Kirton
- Microbiology Department, Oxford University Hospital NHS Foundation Trust, Oxford, UK
| | - Monique Andersson
- Microbiology Department, Oxford University Hospital NHS Foundation Trust, Oxford, UK
| | - Karin Hellner
- Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford, UK
| | - Arturo Reyes-Sandoval
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, The Henry Wellcome Building for Molecular Physiology, Roosevelt Drive, Oxford, UK
| | - Lucy Dorrell
- Nuffield Department of Medicine, University of Oxford and Oxford NIHR Biomedical Research Centre, NDM Research Building, Old Road Campus, Oxford, UK
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Yao Y, Yan Z, Dai S, Li C, Yang L, Liu S, Zhang X, Shi L, Yao Y. Human Papillomavirus Type 16 E1 Mutations Associated with Cervical Cancer in a Han Chinese Population. Int J Med Sci 2019; 16:1042-1049. [PMID: 31341418 PMCID: PMC6643129 DOI: 10.7150/ijms.34279] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/30/2019] [Indexed: 12/20/2022] Open
Abstract
Human papillomavirus type 16 (HPV16) is a high-risk HPV type and a potent carcinogen. HPV E1 is one of the most highly conserved proteins and it plays a central role in initiating HPV DNA replication. In current study, we enrolled 161 HPV16-positive cervical cancer patients (case group) and 171 HPV16-positive asymptomatic individuals (control group) in a study to analyse the association between HPV16 E1 genetic mutations and cervical cancer. The samples of case group were cervical cancer tissues and the samples of control group were cervical exfoliated cells. Three variants (A4, A1-A3 and D3) were found in the case group, 68.3% of the HPV16 E1 sequences belonged to the A4 (As) sub-lineage, 29.2% belonged to the A1-A3 (EUR) sub-lineage, and 2.5% belonged to the D3 (AA1) sub-lineage. Two variants (A4 and A1-A3) occurred in the control group. The A4 (As) sub-lineage was predominant in this group as well (66.1%), followed by the A1-A3 (EUR) sub-lineage (33.9%), but the D3 (AA1) sub-lineage was not found in the control group. The distribution of the HPV16 variants between the case and control groups was significantly different (P<0.05). When the distribution of the HPV16 E1 gene mutations was compared, the distribution of twenty-seven mutations was significantly different between the case and control groups (P<0.05), and twenty-two mutations occurred only in the D3 (AA1) sub-lineage, two were found only in the A4 (As) sub-lineage, one was found in the A1-A3 (EUR) sub-lineage, two was found in both the A4 (As) and A1-A3 (EUR) sub-lineages. In the sub-lineage analysis, the differences in the T933A (A23A), T1014G (D50E) and G2160A (R432R) mutations were statistically significant between the case and control groups for the A4 (As) sub-lineage (P<0.05), and the differences in the T2232C (F456F), G2337A (M491I) and A2547G (P561P) mutations were statistically significant between the case and control groups for the A1-A3 (EUR) sub-lineage (P<0.05). In the current study, we describe specific mutations in the HPV16 E1 gene associated with cervical cancer, and our study will provide a good reference for further functional studies of the relationship between cervical cancer carcinogenesis and HPV genes.
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Affiliation(s)
- Yueting Yao
- Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming 650118, Yunnan, China
| | - Zhiling Yan
- Department of Gynaecologic Oncology, The 3rd Affiliated Hospital of Kunming Medical University, Kunming 650118, China
| | - Shuying Dai
- School of Basic Medical Science, Kunming Medical University, Kunming 650500, China
| | - Chuanyin Li
- Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming 650118, Yunnan, China
| | - Longyu Yang
- Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming 650118, Yunnan, China
| | - Shuyuan Liu
- Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming 650118, Yunnan, China
| | - Xinwen Zhang
- Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming 650118, Yunnan, China
| | - Li Shi
- Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming 650118, Yunnan, China
| | - Yufeng Yao
- Institute of Medical Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Kunming 650118, Yunnan, China
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The SMC5/6 Complex Interacts with the Papillomavirus E2 Protein and Influences Maintenance of Viral Episomal DNA. J Virol 2018; 92:JVI.00356-18. [PMID: 29848583 DOI: 10.1128/jvi.00356-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/21/2018] [Indexed: 12/31/2022] Open
Abstract
The papillomavirus E2 protein executes numerous essential functions related to viral transcription, replication of viral DNA, and viral genome maintenance. Because E2 lacks enzymatic activity, many of these functions are mediated by interactions with host cellular proteins. Unbiased proteomics approaches have successfully identified a number of E2-host protein interactions. We have extended such studies and have identified and validated the cellular proteins structural maintenance of chromosome 5 (SMC5) and SMC6 as interactors of the viral E2 protein. These two proteins make up the core components of the SMC5/6 complex. The SMC5/6 complex is a member of the conserved structural maintenance of chromosomes (SMC) family of proteins, which are essential for genome maintenance. We have examined the role of SMC5/6 in various E2 functions. Our data suggest that SMC6 is not required for E2-mediated transcriptional activation, E1/E2-mediated transient replication, or differentiation-dependent amplification of viral DNA. Our data, however, suggest a role for SMC5/6 in viral genome maintenance.IMPORTANCE The high-risk human papillomaviruses (HPVs) are the etiological cause of cervical cancer and the most common sexually transmitted infection. While the majority of infections may be asymptomatic or cause only benign lesions, persistent infection with the oncogenic high-risk HPV types may lead to serious diseases, such as cervical cancer, anogenital carcinoma, or head and neck oropharyngeal squamous cell carcinoma. The identification of virus-host protein interactions provides insights into the mechanisms of viral DNA persistence, viral genome replication, and cellular transformation. Elucidating the mechanism of early events in the virus replication cycle as well as of integration of viral DNA into host chromatin may present novel antiviral strategies and targets for counteracting persistent infection. The E2 protein is an important viral regulatory protein whose functions are mediated through interactions with host cell proteins. Here we explore the interaction of E2 with SMC5/6 and the functional consequences.
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Chabeda A, Yanez RJR, Lamprecht R, Meyers AE, Rybicki EP, Hitzeroth II. Therapeutic vaccines for high-risk HPV-associated diseases. PAPILLOMAVIRUS RESEARCH (AMSTERDAM, NETHERLANDS) 2018; 5:46-58. [PMID: 29277575 PMCID: PMC5887015 DOI: 10.1016/j.pvr.2017.12.006] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/13/2017] [Accepted: 12/17/2017] [Indexed: 12/16/2022]
Abstract
Cancer is the second leading cause of death worldwide, and it is estimated that Human papillomavirus (HPV) related cancers account for 5% of all human cancers. Current HPV vaccines are extremely effective at preventing infection and neoplastic disease; however, they are prophylactic and do not clear established infections. Therapeutic vaccines which trigger cell-mediated immune responses for the treatment of established infections and malignancies are therefore required. The E6 and E7 early genes are ideal targets for vaccine therapy due to their role in disruption of the cell cycle and their constitutive expression in premalignant and malignant tissues. Several strategies have been investigated for the development of therapeutic vaccines, including live-vector, nucleic acid, peptide, protein-based and cell-based vaccines as well as combinatorial approaches, with several vaccine candidates progressing to clinical trials. With the current understanding of the HPV life cycle, molecular mechanisms of infection, carcinogenesis, tumour biology, the tumour microenvironment and immune response mechanisms, an approved HPV therapeutic vaccine seems to be a goal not far from being achieved. In this article, the status of therapeutic HPV vaccines in clinical trials are reviewed, and the potential for plant-based vaccine production platforms described.
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Affiliation(s)
- Aleyo Chabeda
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa
| | - Romana J R Yanez
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa
| | - Renate Lamprecht
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa
| | - Ann E Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa
| | - Edward P Rybicki
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa; Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
| | - Inga I Hitzeroth
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Rondebosch 7701, South Africa.
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Rumlová M, Ruml T. In vitro methods for testing antiviral drugs. Biotechnol Adv 2018; 36:557-576. [PMID: 29292156 PMCID: PMC7127693 DOI: 10.1016/j.biotechadv.2017.12.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/22/2017] [Accepted: 12/27/2017] [Indexed: 12/24/2022]
Abstract
Despite successful vaccination programs and effective treatments for some viral infections, humans are still losing the battle with viruses. Persisting human pandemics, emerging and re-emerging viruses, and evolution of drug-resistant strains impose continuous search for new antiviral drugs. A combination of detailed information about the molecular organization of viruses and progress in molecular biology and computer technologies has enabled rational antivirals design. Initial step in establishing efficacy of new antivirals is based on simple methods assessing inhibition of the intended target. We provide here an overview of biochemical and cell-based assays evaluating the activity of inhibitors of clinically important viruses.
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Affiliation(s)
- Michaela Rumlová
- Department of Biotechnology, University of Chemistry and Technology, Prague 166 28, Czech Republic.
| | - Tomáš Ruml
- Department of Biochemistry and Microbiology, University of Chemistry and Technology, Prague 166 28, Czech Republic.
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Abstract
The human tumor viruses that replicate as plasmids (we use the term plasmid to avoid any confusion in the term episome, which was coined to mean DNA elements that occur both extrachromosomally and as integrated forms during their life cycles, as does phage lambda) share many features in their DNA synthesis. We know less about their mechanisms of maintenance in proliferating cells, but these mechanisms must underlie their partitioning to daughter cells. One amazing implication of how these viruses are thought to maintain themselves is that while host chromosomes commit themselves to partitioning in mitosis, these tumor viruses would commit themselves to partitioning before mitosis and probably in S phase shortly after their synthesis.
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Human Papillomavirus Replication Regulation by Acetylation of a Conserved Lysine in the E2 Protein. J Virol 2018; 92:JVI.01912-17. [PMID: 29142126 DOI: 10.1128/jvi.01912-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 11/05/2017] [Indexed: 12/25/2022] Open
Abstract
The papillomavirus (PV) E2 protein is a sequence-specific DNA binding protein that recruits cellular factors to its genome in infected epithelial cells. E2 also binds to and loads the viral E1 DNA helicase at the origin of replication. Posttranslational modifications (PTMs) of PV E2 have been identified as potential regulators of E2 functions. We recently reported lysine 111 (K111) as a target of p300 acetylation in bovine PV (BPV). The di-lysines at 111 and 112 are conserved in almost all papillomaviruses. We pursued a mutational approach to query the functional significance of lysine in human PV (HPV) E2. Amino acid substitutions that prevent acetylation, including arginine, were unable to stimulate transcription and E1-mediated DNA replication. The arginine K111 mutant retained E2 transcriptional repression, nuclear localization, DNA and chromatin binding, and association with E2 binding partners involved in PV transcription and replication. While the replication-defective E2-K111R mutant recruited E1 to the viral replication origin, surprisingly, unwinding of the duplex DNA did not occur. In contrast, the K111 glutamine (K111Q) mutant increased origin melting and stimulated replication compared to wild-type E2. These experiments reveal a novel activity of E2 necessary for denaturing the viral origin that likely depends on acetylation of highly conserved lysine 111.IMPORTANCE HPV is one of the most common sexually transmitted infections in the United States. Over 200 HPVs have been described, and they manifest in a variety of ways; they can be asymptomatic or can result in benign lesions (papillomas) or progress to malignancy. Although 90% of infections are asymptomatic and resolve easily, HPV16 and -18 alone are responsible for 70% of all cervical cancers, which are almost entirely caused by HPV infection. Interestingly, 60 to 90% of other cancers have been linked to HPV. The goal of this research is to further elucidate the mechanisms that regulate and mediate viral replication.
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Zhu Y, Wang Y, Hirschhorn J, Welsh KJ, Zhao Z, Davis MR, Feldman S. Human Papillomavirus and Its Testing Assays, Cervical Cancer Screening, and Vaccination. Adv Clin Chem 2017. [PMID: 28629588 DOI: 10.1016/bs.acc.2017.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Human papillomavirus (HPV) was found to be the causative agent for cervical cancer in the 1980s with almost 100% of cervical cancer cases testing positive for HPV. Since then, many studies have been conducted to elucidate the molecular basis of HPV, the mechanisms of carcinogenesis of the virus, and the risk factors for HPV infection. Traditionally, the Papanicolaou test was the primary screening method for cervical cancer. Because of the discovery and evolving understanding of the role of HPV in cervical dysplasia, HPV testing has been recommended as a new method for cervical cancer screening by major professional organizations including the American Cancer Society, American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology. In order to detect HPV infections, many sensitive and specific HPV assays have been developed and used clinically. Different HPV assays with various principles have shown their unique advantages and limitations. In response to a clear causative relationship between high-risk HPV and cervical cancer, HPV vaccines have been developed which utilize virus-like particles to create an antibody response for the prevention of HPV infection. The vaccines have been shown in long-term follow-up studies to be effective for up to 8 years; however, how this may impact screening for vaccinated women remains uncertain. In this chapter, we will review the molecular basis of HPV, its pathogenesis, and the epidemiology of HPV infection and associated cervical cancer, discuss the methods of currently available HPV testing assays as well as recent guidelines for HPV screening, and introduce HPV vaccines as well as their impact on cervical cancer screening and treatments.
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Affiliation(s)
- Yusheng Zhu
- Pennsylvania State University Hershey Medical Center, Hershey, PA, United States.
| | - Yun Wang
- Medical University of South Carolina, Charleston, SC, United States
| | - Julie Hirschhorn
- Pennsylvania State University Hershey Medical Center, Hershey, PA, United States
| | - Kerry J Welsh
- National Institute of Health, Bethesda, MD, United States
| | - Zhen Zhao
- National Institute of Health, Bethesda, MD, United States
| | - Michelle R Davis
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Sarah Feldman
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
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13
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Domain Organization of Vaccinia Virus Helicase-Primase D5. J Virol 2016; 90:4604-4613. [PMID: 26912611 DOI: 10.1128/jvi.00044-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 02/16/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Poxviridae are viruses with a large linear double-stranded DNA genome coding for up to 250 open reading frames and a fully cytoplasmic replication. The double-stranded DNA genome is covalently circularized at both ends. Similar structures of covalently linked extremities of the linear DNA genome are found in the African swine fever virus (asfarvirus) and in the Phycodnaviridae We are studying the machinery which replicates this peculiar genome structure. From our work with vaccinia virus, we give first insights into the overall structure and function of the essential poxvirus virus helicase-primase D5 and show that the active helicase domain of D5 builds a hexameric ring structure. This hexamer has ATPase and, more generally, nucleoside triphosphatase activities that are indistinguishable from the activities of full-length D5 and that are independent of the nature of the base. In addition, hexameric helicase domains bind tightly to single- and double-stranded DNA. Still, the monomeric D5 helicase construct truncated within the D5N domain leads to a well-defined structure, but it does not have ATPase or DNA-binding activity. This shows that the full D5N domain has to be present for hexamerization. This allowed us to assign a function to the D5N domain which is present not only in D5 but also in other viruses of the nucleocytoplasmic large DNA virus (NCLDV) clade. The primase domain and the helicase domain were structurally analyzed via a combination of small-angle X-ray scattering and, when appropriate, electron microscopy, leading to consistent low-resolution models of the different proteins. IMPORTANCE Since the beginning of the 1980s, research on the vaccinia virus replication mechanism has basically stalled due to the absence of structural information. As a result, this important class of pathogens is less well understood than most other viruses. This lack of information concerns in general viruses of the NCLDV clade, which use a superfamily 3 helicase for replication, as do poxviruses. Here we provide for the first time information about the domain structure and DNA-binding activity of D5, the poxvirus helicase-primase. This result not only refines the current model of the poxvirus replication fork but also will lead in the long run to a structural basis for antiviral drug design.
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14
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Lentz MR, Shideler T. Phosphorylation of bovine papillomavirus E1 by the protein kinase CK2 near the nuclear localization signal does not influence subcellular distribution of the protein in dividing cells. Arch Virol 2015; 161:165-9. [PMID: 26467928 DOI: 10.1007/s00705-015-2641-6] [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: 05/26/2015] [Accepted: 10/07/2015] [Indexed: 11/25/2022]
Abstract
The bovine papillomavirus E1 helicase is essential for viral replication. In dividing cells, DNA replication maintains, but does not increase, the viral genome copy number. Replication is limited by low E1 expression and an E1 nucleocytoplasmic shuttling mechanism. Shuttling is controlled in part by phosphorylation of E1 by cellular kinases. Here we investigate conserved sites for phosphorylation by kinase CK2 within the E1 nuclear localization signal. When these CK2 sites are mutated to either alanine or aspartic acid, no change in replication phenotype is observed, and there is no effect on the subcellular distribution of E1, which remains primarily nuclear. This demonstrates that phosphorylation of E1 by CK2 at these sites is not a factor in regulating viral DNA replication in dividing cells.
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Affiliation(s)
- Michael R Lentz
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA.
| | - Tess Shideler
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA
- Department of Pathology, University of New Mexico, Albuquerque, NM, 87131, USA
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15
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Kanginakudru S, DeSmet M, Thomas Y, Morgan IM, Androphy EJ. Levels of the E2 interacting protein TopBP1 modulate papillomavirus maintenance stage replication. Virology 2015; 478:129-35. [PMID: 25666521 DOI: 10.1016/j.virol.2015.01.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 01/05/2015] [Accepted: 01/12/2015] [Indexed: 11/15/2022]
Abstract
The evolutionarily conserved DNA topoisomerase II beta-binding protein 1 (TopBP1) functions in DNA replication, DNA damage response, and cell survival. We analyzed the role of TopBP1 in human and bovine papillomavirus genome replication. Consistent with prior reports, TopBP1 co-localized in discrete nuclear foci and was in complex with papillomavirus E2 protein. Similar to E2, TopBP1 is recruited to the region of the viral origin of replication during G1/S and early S phase. TopBP1 knockdown increased, while over-expression decreased transient virus replication, without affecting cell cycle. Similarly, using cell lines harboring HPV-16 or HPV-31 genome, TopBP1 knockdown increased while over-expression reduced viral copy number relative to genomic DNA. We propose a model in which TopBP1 serves dual roles in viral replication: it is essential for initiation of replication yet it restricts viral copy number.
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Affiliation(s)
- Sriramana Kanginakudru
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Marsha DeSmet
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Yanique Thomas
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Iain M Morgan
- VCU Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia, USA.
| | - Elliot J Androphy
- Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA.
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16
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A conserved regulatory module at the C terminus of the papillomavirus E1 helicase domain controls E1 helicase assembly. J Virol 2014; 89:1129-42. [PMID: 25378487 DOI: 10.1128/jvi.01903-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Viruses frequently combine multiple activities into one polypeptide to conserve coding capacity. This strategy creates regulatory challenges to ascertain that the combined activities are compatible and do not interfere with each other. The papillomavirus E1 protein, as many other helicases, has the intrinsic ability to form hexamers and double hexamers (DH) that serve as the replicative DNA helicase. However, E1 also has the more unusual ability to generate local melting by forming a double trimer (DT) complex that can untwist the double-stranded origin of DNA replication (ori) DNA in preparation for DH formation. Here we describe a switching mechanism that allows the papillomavirus E1 protein to form these two different kinds of oligomers and to transition between them. We show that a conserved regulatory module attached to the E1 helicase domain blocks hexamer and DH formation and promotes DT formation. In the presence of the appropriate trigger, the inhibitory effect of the regulatory module is relieved and the transition to DH formation can occur. IMPORTANCE This study provides a mechanistic understanding into how a multifunctional viral polypeptide can provide different, seemingly incompatible activities. A conserved regulatory sequence module attached to the AAA+ helicase domain in the papillomavirus E1 protein allows the formation of different oligomers with different biochemical activities.
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17
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Abstract
E1, an ATP-dependent DNA helicase, is the only enzyme encoded by papillomaviruses (PVs). It is essential for replication and amplification of the viral episome in the nucleus of infected cells. To do so, E1 assembles into a double-hexamer at the viral origin, unwinds DNA at the origin and ahead of the replication fork and interacts with cellular DNA replication factors. Biochemical and structural studies have revealed the assembly pathway of E1 at the origin and how the enzyme unwinds DNA using a spiral escalator mechanism. E1 is tightly regulated in vivo, in particular by post-translational modifications that restrict its accumulation in the nucleus. Here we review how different functional domains of E1 orchestrate viral DNA replication, with an emphasis on their interactions with substrate DNA, host DNA replication factors and modifying enzymes. These studies have made E1 one of the best characterized helicases and provided unique insights on how PVs usurp different host-cell machineries to replicate and amplify their genome in a tightly controlled manner.
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18
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Recombination-dependent oligomerization of human papillomavirus genomes upon transient DNA replication. J Virol 2013; 87:12051-68. [PMID: 23986589 DOI: 10.1128/jvi.01798-13] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We describe the extensive and progressive oligomerization of human papillomavirus (HPV) genomes after transfection into the U2OS cell line. The HPV genomic oligomers are extrachromosomal concatemeric molecules containing the viral genome in a head-to-tail orientation. The process of oligomerization does not depend on the topology of the input DNA, and it does not require any other viral factors besides replication proteins E1 and E2. We provide evidence that oligomerization of the HPV18 and HPV11 genomes involves homologous recombination. We also demonstrate oligomerization of the HPV18 and HPV11 genomes in SiHa, HeLa, and C-33 A cell lines and provide examples of oligomeric HPV genomes in clinical samples obtained from HPV-infected patients.
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19
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CK2 phosphorylation inactivates DNA binding by the papillomavirus E1 and E2 proteins. J Virol 2013; 87:7668-79. [PMID: 23637413 DOI: 10.1128/jvi.00345-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Papillomaviruses have complex life cycles that are understood only superficially. Although it is well established that the viral E1 and E2 proteins play key roles in controlling viral transcription and DNA replication, how these factors are regulated is not well understood. Here, we demonstrate that phosphorylation by the protein kinase CK2 controls the biochemical activities of the bovine papillomavirus E1 and E2 proteins by modifying their DNA binding activity. Phosphorylation at multiple sites in the N-terminal domain in E1 results in the loss of sequence-specific DNA binding activity, a feature that is also conserved in human papillomavirus (HPV) E1 proteins. The bovine papillomavirus (BPV) E2 protein, when phosphorylated by CK2 on two specific sites in the hinge, also loses its site-specific DNA binding activity. Mutation of these sites in E2 results in greatly increased levels of latent viral DNA replication, indicating that CK2 phosphorylation of E2 is a negative regulator of viral DNA replication during latent viral replication. In contrast, mutation of the N-terminal phosphorylation sites in E1 has no effect on latent viral DNA replication. We propose that the phosphorylation of the N terminus of E1 plays a role only in vegetative viral DNA replication, and consistent with such a role, caspase 3 cleavage of E1, which has been shown to be necessary for vegetative viral DNA replication, restores the DNA binding activity to phosphorylated E1.
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20
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Recruitment of Brd4 to the human papillomavirus type 16 DNA replication complex is essential for replication of viral DNA. J Virol 2013; 87:3871-84. [PMID: 23365439 DOI: 10.1128/jvi.03068-12] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Replication of the human papillomavirus (HPV) DNA genome relies on viral factors E1 and E2 and the cellular replication machinery. Bromodomain-containing protein 4 (Brd4) interacts with viral E2 protein to mediate papillomavirus (PV) genome maintenance and viral transcription. However, the functional role of Brd4 in the HPV life cycle remains to be clearly defined. In this study, we provide the first look into the E2-Brd4 interaction in the presence of other important viral factors, such as the HPV16 E1 protein and the viral genome. We show that Brd4 is recruited to actively replicating HPV16 origin foci together with HPV16 E1, E2, and a number of the cellular replication factors: replication protein A70 (RPA70), replication factor C1 (RFC1), and DNA polymerase δ. Mutagenesis disrupting the E2-Brd4 interaction abolishes the formation of the HPV16 replication complex and impairs HPV16 DNA replication in cells. Brd4 was further demonstrated to be necessary for HPV16 viral DNA replication using a cell-free replication system in which depletion of Brd4 by small interfering RNA (siRNA) silencing leads to impaired HPV16 viral DNA replication and recombinant Brd4 protein is able to rescue viral DNA replication. In addition, releasing endogenous Brd4 from cellular chromatin by using the bromodomain inhibitor JQ1(+) enhances HPV16 DNA replication, demonstrating that the role of Brd4 in HPV DNA replication could be uncoupled from its function in chromatin-associated transcriptional regulation and cell cycle control. Our study reveals a new role for Brd4 in HPV genome replication, providing novel insights into understanding the life cycle of this oncogenic DNA virus.
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21
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Engagement of the ATR-dependent DNA damage response at the human papillomavirus 18 replication centers during the initial amplification. J Virol 2012; 87:951-64. [PMID: 23135710 DOI: 10.1128/jvi.01943-12] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
We have previously demonstrated that the human papillomavirus (HPV) genome replicates effectively in U2OS cells after transfection using electroporation. The transient extrachromosomal replication, stable maintenance, and late amplification of the viral genome could be studied for high- and low-risk mucosal and cutaneous papillomaviruses. Recent findings indicate that the cellular DNA damage response (DDR) is activated during the HPV life cycle and that the viral replication protein E1 might play a role in this process. We used a U2OS cell-based system to study E1-dependent DDR activation and the involvement of these pathways in viral transient replication. We demonstrated that the E1 protein could cause double-strand DNA breaks in the host genome by directly interacting with DNA. This activity leads to the induction of an ATM-dependent signaling cascade and cell cycle arrest in the S and G(2) phases. However, the transient replication of HPV genomes in U2OS cells induces the ATR-dependent pathway, as shown by the accumulation of γH2AX, ATR-interacting protein (ATRIP), and topoisomerase IIβ-binding protein 1 (TopBP1) in viral replication centers. Viral oncogenes do not play a role in this activation, which is induced only through DNA replication or by replication proteins E1 and E2. The ATR pathway in viral replication centers is likely activated through DNA replication stress and might play an important role in engaging cellular DNA repair/recombination machinery for effective replication of the viral genome upon active amplification.
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22
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Regulation of nucleocytoplasmic trafficking of viral proteins: an integral role in pathogenesis? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:2176-90. [PMID: 21530593 PMCID: PMC7114211 DOI: 10.1016/j.bbamcr.2011.03.019] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 03/15/2011] [Accepted: 03/30/2011] [Indexed: 12/24/2022]
Abstract
Signal-dependent targeting of proteins into and out of the nucleus is mediated by members of the importin (IMP) family of transport receptors, which recognise targeting signals within a cargo protein and mediate passage through the nuclear envelope-embedded nuclear pore complexes. Regulation of this process is paramount to processes such as cell division and differentiation, but is also critically important for viral replication and pathogenesis; phosphorylation appears to play a major role in regulating viral protein nucleocytoplasmic trafficking, along with other posttranslational modifications. This review focuses on viral proteins that utilise the host cell IMP machinery in order to traffic into/out of the nucleus, and in particular those where trafficking is critical to viral replication and/or pathogenesis, such as simian virus SV40 large tumour antigen (T-ag), human papilloma virus E1 protein, human cytomegalovirus processivity factor ppUL44, and various gene products from RNA viruses such as Rabies. Understanding of the mechanisms regulating viral protein nucleocytoplasmic trafficking is paramount to the future development of urgently needed specific and effective anti-viral therapeutics. This article was originally intended for the special issue "Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import". The Publisher apologizes for any inconvenience caused.
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23
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Wang T, Chang P, Wang L, Yao Q, Guo W, Chen J, Yan T, Cao C. The role of human papillomavirus infection in breast cancer. Med Oncol 2011; 29:48-55. [PMID: 21318737 DOI: 10.1007/s12032-010-9812-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 12/29/2010] [Indexed: 01/04/2023]
Abstract
Breast cancer is the leading female cancer and the third most common cause of cancer deaths worldwide. Many studies have suggested a possible link between breast cancer pathogenesis and viral infection, particularly mouse mammary tumour virus, simian virus 40, Epstein-Barr virus, and human papillomavirus (HPV). A significant number of recent studies have reported that approximately 29% of human breast cancer tissues were positive for high-risk HPV subtypes, especially HPV subtypes 16, 18, or 33. In contrast, several other investigations did not detect any HPV subtypes in either breast cancer tissue or normal breast tissue from patients diagnosed with breast cancer. Given these conflicting data and the established complexity of the association between HPV with other cancers, a definitive relationship between human breast cancer and HPV infection has not been determined. Recent advances in laboratory methodologies aim to overcome the inherent challenges in detecting HPV in breast cancer tissue. There is an urgent need to obtain additional evidence in order to assess the possibility of breast cancer prevention using HPV vaccines.
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Affiliation(s)
- Ting Wang
- Department of Vascular and Endocrine Surgery, Xijing Hospital, Fourth Military Medical University, No 127, Changle West Road, 710032 Xi'an, Shaanxi Province, China
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24
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Duderstadt KE, Mott ML, Crisona NJ, Chuang K, Yang H, Berger JM. Origin remodeling and opening in bacteria rely on distinct assembly states of the DnaA initiator. J Biol Chem 2010; 285:28229-39. [PMID: 20595381 DOI: 10.1074/jbc.m110.147975] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The initiation of DNA replication requires the melting of chromosomal origins to provide a template for replisomal polymerases. In bacteria, the DnaA initiator plays a key role in this process, forming a large nucleoprotein complex that opens DNA through a complex and poorly understood mechanism. Using structure-guided mutagenesis, biochemical, and genetic approaches, we establish an unexpected link between the duplex DNA-binding domain of DnaA and the ability of the protein to both self-assemble and engage single-stranded DNA in an ATP-dependent manner. Intersubunit cross-talk between this domain and the DnaA ATPase region regulates this link and is required for both origin unwinding in vitro and initiator function in vivo. These findings indicate that DnaA utilizes at least two different oligomeric conformations for engaging single- and double-stranded DNA, and that these states play distinct roles in controlling the progression of initiation.
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Affiliation(s)
- Karl E Duderstadt
- Biophysics Graduate Group, California Institute for Quantitative Biology, University of California, Berkeley, California 94720, USA
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25
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Structure-based mutational analysis of the bovine papillomavirus E1 helicase domain identifies residues involved in the nonspecific DNA binding activity required for double trimer formation. J Virol 2010; 84:4264-76. [PMID: 20147403 DOI: 10.1128/jvi.02214-09] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The papillomavirus E1 protein is a multifunctional initiator protein responsible for preparing the viral DNA template for initiation of DNA replication. The E1 protein encodes two DNA binding activities that are required for initiation of DNA replication. A well-characterized sequence-specific DNA binding activity resides in the E1 DBD and is used to tether E1 to the papillomavirus ori. A non-sequence-specific DNA binding activity is also required for formation of the E1 double trimer (DT) complex, which is responsible for the local template melting that precedes loading of the E1 helicase. This DNA binding activity is very poorly understood. We use a structure-based mutagenesis approach to identify residues in the E1 helicase domain that are required for the non-sequence-specific DNA binding and DT formation. We found that three groups of residues are involved in nonspecific DNA binding: the E1 beta-hairpin structure containing R505, K506, and H507; a hydrophobic loop containing F464; and a charged loop containing K461 together generate the binding surface involved in nonspecific DNA binding. These residues are well conserved in the T antigens from the polyomaviruses, indicating that the polyomaviruses share this nonspecific DNA binding activity.
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26
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Mutations in Sensor 1 and Walker B in the bovine papillomavirus E1 initiator protein mimic the nucleotide-bound state. J Virol 2009; 84:1912-9. [PMID: 19939914 DOI: 10.1128/jvi.01756-09] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Viral replication initiator proteins are multifunctional proteins that utilize ATP binding and hydrolysis by their AAA+ modules for multiple functions in the replication of their viral genomes. These proteins are therefore of particular interest for understanding how AAA+ proteins carry out multiple ATP driven functions. We have performed a comprehensive mutational analysis of the residues involved in ATP binding and hydrolysis in the papillomavirus E1 initiator protein based on the recent structural data. Ten of the eleven residues that were targeted were defective for ATP hydrolysis, and seven of these were also defective for ATP binding. The three mutants that could still bind nucleotide represent the Walker B motif (D478 and D479) and Sensor 1 (N523), three residues that are in close proximity to each other and generally are considered to be involved in ATP hydrolysis. Surprisingly, however, two of these mutants, D478A and N523A, mimicked the nucleotide bound state and were capable of binding DNA in the absence of nucleotide. However, these mutants could not form the E1 double trimer in the absence of nucleotide, demonstrating that there are two qualitatively different consequences of ATP binding by E1, one that can be mimicked by D478A and N523A and one which cannot.
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27
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Topography of bovine papillomavirus E2 protein on the viral genome during the cell cycle. Virology 2009; 393:258-64. [PMID: 19716579 DOI: 10.1016/j.virol.2009.07.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 06/02/2009] [Accepted: 07/28/2009] [Indexed: 11/23/2022]
Abstract
The multifunctional papillomavirus E2 protein serves important roles in transcriptional activation and genome maintenance and cooperates with the viral E1 helicase for the initiation of viral DNA replication. The bovine papillomavirus genome contains seventeen E2 binding sites, largely concentrated within the long control region, and a single E1 binding site at the origin of viral replication. Using chromatin immunoprecipitation (ChIP) followed by restriction enzyme digestion and PCR, we show that BPV E1 was present only in the region of an active origin of replication and that BPV E2 remained attached to definable segments of the viral genome at specific stages of the cell cycle.
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28
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Stojanova A, Penn LZ. The role of INI1/hSNF5 in gene regulation and cancer. Biochem Cell Biol 2009; 87:163-77. [PMID: 19234532 DOI: 10.1139/o08-113] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The precise modulation of chromatin dynamics is an essential and complex process that ensures the integrity of transcriptional regulation and prevents the transition of a normal cell into a cancerous one. ATP-dependent chromatin remodeling enzymes are multisubunit complexes that play a pivotal role in this operation through the mobilization of nucleosomes to promote DNA accessibility. Chromatin remodeling is mediated by the interaction of DNA-binding factors and individual members of this complex, directing its targeted recruitment to specific regulatory regions. In this review, we discuss a core subunit of the SWI/SNF ATP-dependent chromatin remodeling complex, known as INI1/hSNF5, in the context of transcriptional regulation and impact on cancer biology. In particular, we review current knowledge of the diverse protein interactions between INI1/hSNF5 and viral and cellular factors, with a special emphasis on the potent oncogene c-Myc.
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Affiliation(s)
- Angelina Stojanova
- Department of Medical Biophysics, University of Toronto, Toronto, ONM5G2M9, Canada
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29
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Kadaja M, Isok-Paas H, Laos T, Ustav E, Ustav M. Mechanism of genomic instability in cells infected with the high-risk human papillomaviruses. PLoS Pathog 2009; 5:e1000397. [PMID: 19390600 PMCID: PMC2666264 DOI: 10.1371/journal.ppat.1000397] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 03/25/2009] [Indexed: 11/18/2022] Open
Abstract
In HPV–related cancers, the “high-risk” human papillomaviruses (HPVs) are frequently found integrated into the cellular genome. The integrated subgenomic HPV fragments express viral oncoproteins and carry an origin of DNA replication that is capable of initiating bidirectional DNA re-replication in the presence of HPV replication proteins E1 and E2, which ultimately leads to rearrangements within the locus of the integrated viral DNA. The current study indicates that the E1- and E2-dependent DNA replication from the integrated HPV origin follows the “onion skin”–type replication mode and generates a heterogeneous population of replication intermediates. These include linear, branched, open circular, and supercoiled plasmids, as identified by two-dimensional neutral-neutral gel-electrophoresis. We used immunofluorescence analysis to show that the DNA repair/recombination centers are assembled at the sites of the integrated HPV replication. These centers recruit viral and cellular replication proteins, the MRE complex, Ku70/80, ATM, Chk2, and, to some extent, ATRIP and Chk1 (S317). In addition, the synthesis of histone γH2AX, which is a hallmark of DNA double strand breaks, is induced, and Chk2 is activated by phosphorylation in the HPV–replicating cells. These changes suggest that the integrated HPV replication intermediates are processed by the activated cellular DNA repair/recombination machinery, which results in cross-chromosomal translocations as detected by metaphase FISH. We also confirmed that the replicating HPV episomes that expressed the physiological levels of viral replication proteins could induce genomic instability in the cells with integrated HPV. We conclude that the HPV replication origin within the host chromosome is one of the key factors that triggers the development of HPV–associated cancers. It could be used as a starting point for the “onion skin”–type of DNA replication whenever the HPV plasmid exists in the same cell, which endangers the host genomic integrity during the initial integration and after the de novo infection. High-risk human papillomavirus infection can cause several types of cancers. During the normal virus life cycle, these viruses maintain their genomes as multicopy nuclear plasmids in infected cells. However, in cancer cells, the viral plasmids are lost, which leaves one of the HPV genomes to be integrated into the genome of the host cell. We suggest that the viral integration and the coexistence of episomal and integrated HPV genomes in the same cell play key roles in early events that lead to the formation of HPV–dependent cancer cells. We show that HPV replication proteins expressed at the physiological level from the viral extrachromosomal genome are capable of replicating episomal and integrated HPV simultaneously. Unscheduled replication of the integrated HPV induces a variety of changes in the host genome, such as excision, repair, recombination, and amplification, which also involve the flanking cellular DNA. As a result, genomic modifications occur, which could have a role in reprogramming the HPV–infected cells that leads to the development of cancer. We believe that the mechanism described in this study may reflect the underlying processes that take place in the genome of the HPV–infected cells and may also play a role in the formation of other types of cancers.
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Affiliation(s)
- Meelis Kadaja
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
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Papillomavirus DNA replication — From initiation to genomic instability. Virology 2009; 384:360-8. [DOI: 10.1016/j.virol.2008.11.032] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Accepted: 11/18/2008] [Indexed: 12/25/2022]
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Abstract
Papillomaviruses establish persistent infection in the dividing, basal epithelial cells of the host. The viral genome is maintained as a circular, double-stranded DNA, extrachromosomal element within these cells. Viral genome amplification occurs only when the epithelial cells differentiate and viral particles are shed in squames that are sloughed from the surface of the epithelium. There are three modes of replication in the papillomavirus life cycle. Upon entry, in the establishment phase, the viral genome is amplified to a low copy number. In the second maintenance phase, the genome replicates in dividing cells at a constant copy number, in synchrony with the cellular DNA. And finally, in the vegetative or productive phase, the viral DNA is amplified to a high copy number in differentiated cells and is destined to be packaged in viral capsids. This review discusses the cis elements and protein factors required for each stage of papillomavirus replication.
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Affiliation(s)
- Alison A McBride
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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Duderstadt KE, Berger JM. AAA+ ATPases in the initiation of DNA replication. Crit Rev Biochem Mol Biol 2008; 43:163-87. [PMID: 18568846 DOI: 10.1080/10409230802058296] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
All cellular organisms and many viruses rely on large, multi-subunit molecular machines, termed replisomes, to ensure that genetic material is accurately duplicated for transmission from one generation to the next. Replisome assembly is facilitated by dedicated initiator proteins, which serve to both recognize replication origins and recruit requisite replisomal components to the DNA in a cell-cycle coordinated manner. Exactly how imitators accomplish this task, and the extent to which initiator mechanisms are conserved among different organisms have remained outstanding issues. Recent structural and biochemical findings have revealed that all cellular initiators, as well as the initiators of certain classes of double-stranded DNA viruses, possess a common adenine nucleotide-binding fold belonging to the ATPases Associated with various cellular Activities (AAA+) family. This review focuses on how the AAA+ domain has been recruited and adapted to control the initiation of DNA replication, and how the use of this ATPase module underlies a common set of initiator assembly states and functions. How biochemical and structural properties correlate with initiator activity, and how species-specific modifications give rise to unique initiator functions, are also discussed.
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Affiliation(s)
- Karl E Duderstadt
- Department Molecular and Cell Biology and Biophysics Graduate Group, California Institute for Quantitative Biology, University of California, Berkeley, California 94720-3220, USA.
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Human papillomavirus in cervical and head-and-neck cancer. ACTA ACUST UNITED AC 2008; 5:24-31. [PMID: 18097454 DOI: 10.1038/ncponc0984] [Citation(s) in RCA: 181] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Accepted: 08/08/2007] [Indexed: 11/09/2022]
Abstract
Cervical cancer is a major cause of cancer mortality in women worldwide and is initiated by infection with high-risk human papillomaviruses (HPVs). High-risk HPVs, especially HPV-16, are associated with other anogenital cancers and a subgroup of head-and-neck cancers. Indeed, HPV infection could account for the development of head-and-neck cancer in certain individuals that lack the classical risk factors for this disease (tobacco and alcohol abuse). This Review summarizes the main events of the HPV life cycle, the functions of the viral proteins, and the implications of HPV infection on their hosts, with an emphasis on carcinogenic mechanisms and disease outcomes in head-and-neck cancer. The demonstration that HPVs have a role in human carcinogenesis has allowed the development of preventive and therapeutic strategies aimed at reducing the incidence and mortality of HPV-associated cancers.
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Brown C, Kowalczyk AM, Taylor ER, Morgan IM, Gaston K. P53 represses human papillomavirus type 16 DNA replication via the viral E2 protein. Virol J 2008; 5:5. [PMID: 18190682 PMCID: PMC2249571 DOI: 10.1186/1743-422x-5-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Accepted: 01/11/2008] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Human papillomavirus (HPV) DNA replication can be inhibited by the cellular tumour suppressor protein p53. However, the mechanism through which p53 inhibits viral replication and the role that this might play in the HPV life cycle are not known. The papillomavirus E2 protein is required for efficient HPV DNA replication and also regulates viral gene expression. E2 represses transcription of the HPV E6 and E7 oncogenes and can thereby modulate indirectly host cell proliferation and survival. In addition, the E2 protein from HPV 16 has been shown to bind p53 and to be capable of inducing apoptosis independently of E6 and E7. RESULTS Here we use a panel of E2 mutants to confirm that mutations which block the induction of apoptosis via this E6/E7-independent pathway, have little or no effect on the induction of apoptosis by the E6/E7-dependent pathway. Although these mutations in E2 do not affect the ability of the protein to mediate HPV DNA replication, they do abrogate the repressive effects of p53 on the transcriptional activity of E2 and prevent the inhibition of E2-dependent HPV DNA replication by p53. CONCLUSION These data suggest that p53 down-regulates HPV 16 DNA replication via the E2 protein.
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Affiliation(s)
- Craig Brown
- Department of Biochemistry, School of Medical School, University of Bristol, Bristol, UK
| | - Anna M Kowalczyk
- Department of Biochemistry, School of Medical School, University of Bristol, Bristol, UK
| | - Ewan R Taylor
- Institute of Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Iain M Morgan
- Institute of Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Kevin Gaston
- Department of Biochemistry, School of Medical School, University of Bristol, Bristol, UK
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Kisseljov F, Sakharova O, Kondratjeva T. Chapter 2 Cellular and Molecular Biological Aspects of Cervical Intraepithelial Neoplasia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 271:35-95. [DOI: 10.1016/s1937-6448(08)01202-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Abstract
Human papillomaviruses complete their life cycle in differentiating epithelial cells that would not normally be competent for either cellular or viral DNA replication. To overcome this, papillomaviruses encode two groups of proteins that work together in the upper epithelial layers to amplify viral genomes. The E6 and E7 proteins play a critical role in driving differentiating epithelial cells that have left the basal layer, back into the cell cycle, in order to produce a replication-competent environment that can be used by the virus for genome amplification. Papillomavirus replication is heavily dependent on cellular replication proteins, but in addition needs the viral E1 and E2 proteins, which act to unwind viral DNA around the origin of replication, and to recruit essential cellular proteins to the replication site. Recent work using mutant viral genomes has suggested that two other viral proteins, E4 and E5, contribute to efficient replication in the upper epithelial layers, although the mechanisms by which they do this have not yet been clearly established. Genome amplification in the upper epithelial layers differs from maintenance replication in the basal layer, where viral genome replication appears coupled to that of the cellular genome. The onset of genome amplification during differentiation is thought to be triggered at least in part by an increase in E1 and E2 levels, and possibly also by a change in the relative levels of the two proteins. The role of E6 and E7 in basal cell replication is, however, uncertain and there is even some question as to the exact requirement for E1. Although similarities in papillomavirus lifecycle organization and protein function suggest a common mechanism by which viral DNA replication is regulated, differences in the site of infection and transmission route appear to manifest themselves as differences in the timing and extent of genome amplification. Understanding the patterns of protein expression seen during natural infection will be important in fully understanding how these differences arise.
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Affiliation(s)
- John Doorbar
- National Institute for Medical Research, Division of Virology, The Ridgeway, Mill Hill, London, NW7 1AA, UK
| | - Kenneth Raj
- National Institute for Medical Research, Division of Virology, The Ridgeway, Mill Hill, London, NW7 1AA, UK
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Liu X, Schuck S, Stenlund A. Adjacent residues in the E1 initiator beta-hairpin define different roles of the beta-hairpin in Ori melting, helicase loading, and helicase activity. Mol Cell 2007; 25:825-37. [PMID: 17386260 DOI: 10.1016/j.molcel.2007.02.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2006] [Revised: 12/22/2006] [Accepted: 02/05/2007] [Indexed: 11/30/2022]
Abstract
We have analyzed two residues in the helicase domain of the E1 initiator protein. These residues are part of a highly conserved structural motif, the beta-hairpin, which is present in the helicase domain of all papovavirus initiator proteins. These proteins are unique in their ability to transition from local template melting activity to unwinding. We demonstrate that the beta-hairpin has two functions. First, it is the tool used by the E1 double trimer (DT) to pry open and melt double-stranded DNA. Second, it is required for the unwinding activity of the hexameric E1 helicase. The fact that the same structural element, but not the same residues, contacts both dsDNA in the DT for melting and ssDNA in the double hexamer (DH) for helicase activity provides a link between local origin melting and DNA helicase activity and suggests how the transition between these two states comes about.
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Affiliation(s)
- Xiaofei Liu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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Kanda T, Kukimoto I. [Human papillomavirus and cervical cancer]. Uirusu 2007; 56:219-30. [PMID: 17446671 DOI: 10.2222/jsv.56.219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Human papillomavirus (HPV) is a small non-enveloped icosahedral virus with a circular double-stranded DNA genome of 8 kilo base pairs. HPV particles reach and infect the basal cells of the stratified epithelia through small epithelial lesions. In the basal cells the viral DNA is maintained as episomes, which start to replicate when the host cells initiate terminal differentiation. In these differentiating cells the degradation of p53 by the E6 protein and the abrogation of the pRb functions by the E7 protein lead to the reactivation of the DNA synthesis machinery. After virus propagation the host cells usually die. On the other hand, in some of the infected cells, the E6 and E7 genes are integrated on rare occasion into cell DNA. The cell continuously expressing the E6 and E7 proteins from the integrated genes is immortalized and sometimes acquires malignant phenotype induced by the accumulated damages to DNA. Of more than 100 HPV genotypes recorded to date, 13 including types 16 and 18 are associated with cervical cancer. Expression of HPV major capsid protein L1 in some cultured cells results in production of virus-like particles (VLPs). The VLPs of types 6, 11, 16, and 18 were used as a prophylactic vaccine in recent clinical trials and shown to successfully induce type-specific neutralizing antibodies in the recipients.
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Affiliation(s)
- Tadahito Kanda
- Center for Pathogen Genomics, National Institute of Infectious Diseases.
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Kadaja M, Sumerina A, Verst T, Ojarand M, Ustav E, Ustav M. Genomic instability of the host cell induced by the human papillomavirus replication machinery. EMBO J 2007; 26:2180-91. [PMID: 17396148 PMCID: PMC1852791 DOI: 10.1038/sj.emboj.7601665] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Accepted: 03/05/2007] [Indexed: 12/18/2022] Open
Abstract
Development of invasive cervical cancer upon infection by 'high-risk' human papillomavirus (HPV) in humans is a stepwise process in which some of the initially episomal 'high-risk' type of HPVs (HR-HPVs) integrate randomly into the host cell genome. We show that HPV replication proteins E1 and E2 are capable of inducing overamplification of the genomic locus where HPV origin has been integrated. Clonal analysis of the cells in which the replication from integrated HPV origin was induced showed excision, rearrangement and de novo integration of the HPV containing and flanking cellular sequences. These data suggest that papillomavirus replication machinery is capable of inducing genomic changes of the host cell that may facilitate the formation of the HPV-dependent cancer cell.
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Affiliation(s)
- Meelis Kadaja
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Alina Sumerina
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Tatjana Verst
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Mari Ojarand
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Ene Ustav
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Mart Ustav
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
- Institute of Technology, University of Tartu, Tartu, Estonia
- Department of Biomedical Technology, Institute of Technology, University of Tartu and Estonian Biocentre, Nooruse 1, Tartu 50411, Estonia. Tel.: +372 737 4800; Fax: +372 737 4900; E-mail:
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Wang W, Wang C, Xu S, Chen C, Tong X, Liang Y, Dong X, Lei Y, Zheng X, Yu J, Wang J. Detection of HPV-2 and identification of novel mutations by whole genome sequencing from biopsies of two patients with multiple cutaneous horns. J Clin Virol 2007; 39:34-42. [PMID: 17368088 DOI: 10.1016/j.jcv.2007.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 01/11/2007] [Indexed: 10/23/2022]
Abstract
BACKGROUND Human papillomavirus-2 (HPV-2) is generally associated with common warts. The association of cutaneous horns with HPV-2 infection has never been reported. OBJECTIVES To identify the papillomavirus (PV) type(s) involved in cutaneous horns and analysis the genomes of these viruses. STUDY DESIGN We screened biopsies from two patients with multiple cutaneous horns using PV type-specific PCR assays, and sequenced the whole genomes of the viruses by a PCR-by-PCR strategy. Sequence comparison with the reference genome and its closely related PVs in the same phylogenetic group was performed to identify sequence variation across the genome(s) of newly detected PV(s). RESULTS Two strains of HPV-2 were identified from the biopsies of two patients respectively. No double or multiple infections were detected. Novel mutations were found in the HPV-2 genome, located both in the coding and non-coding regions. Amino acid changes occurred only in E1 and E7 ORFs. The two strains also shared several mutations at the same positions. CONCLUSIONS Each patient was infected with a single strain of HPV-2 that developed unique mutations; HPV-2 may play a role in the onset and development of cutaneous horns; amino acid changes in functionally significant viral proteins may confer differential pathogenic risks.
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Affiliation(s)
- Wei Wang
- Beijing Genomics Institute, Chinese Academy of Sciences, Beijing 101300, China
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41
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Green KL, Gaston K. Development of a topical protein therapeutic for human papillomavirus and associated cancers. BioDrugs 2007; 20:209-18. [PMID: 16831020 DOI: 10.2165/00063030-200620040-00002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Human papillomaviruses (HPVs) are the causative agents of several disease states, including genital warts and cervical cancer. There are around 500 million cases of genital warts per annum worldwide and around 450,000 cases of cervical cancer. Although HPV vaccines should eventually reduce the incidence of these diseases, new and effective treatments are still urgently required. The E2 (early) proteins from some HPV types induce growth arrest and apoptosis, and these proteins could be used as therapeutics for HPV-induced disease. A major obstacle to this approach concerns the delivery of the protein to HPV-transformed cells and/or HPV-infected cells in vivo. One possible solution is to use recombinant viruses to deliver E2. Another possible solution is to use purified E2 proteins or E2 fusion proteins. The herpes simplex virus VP22 protein is one of a small number of proteins that have been shown to cross the cell membrane with high efficiency. VP22-E2 fusion proteins produced in bacterial cells are able to enter mammalian cells and induce apoptosis. This suggests that VP22-E2 fusion proteins could be topically applied as a treatment for HPV-induced diseases, most probably post-surgery. In this review, we discuss this and other approaches to the topical delivery of selective therapeutic agents against HPV-associated conditions.
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Affiliation(s)
- Katie L Green
- Department of Biochemistry, School of Medical Sciences, University of Bristol, Bristol, UK
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Schuck S, Stenlund A. ATP-dependent minor groove recognition of TA base pairs is required for template melting by the E1 initiator protein. J Virol 2007; 81:3293-302. [PMID: 17202221 PMCID: PMC1866042 DOI: 10.1128/jvi.02432-06] [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: 11/20/2022] Open
Abstract
Template melting is an essential step in the initiation of DNA replication, but the mechanism of template melting is unknown for any replicon. Here we demonstrate that melting of the bovine papillomavirus type 1 ori is a sequence-dependent process which relies on specific recognition of TA base pairs in the minor groove by the E1 initiator. We show that correct template melting is a prerequisite for the formation of a stable double hexamer with helicase activity and that ori mutants that fail to melt correctly are defective for ori unwinding and DNA replication in vivo. Our results also indicate that melting of the DNA is achieved by destabilization of the double helix along its length through multiple interactions with E1, each of which is responsible for melting of a few base pairs, resulting in the extensive melting that is required for initiation of DNA replication.
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Affiliation(s)
- Stephen Schuck
- Cold Spring Harbor Laboratory, 1 Bungtown Road, P.O. Cold Spring Harbor, NY 11724, USA
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Hsu CY, Mechali F, Bonne-Andrea C. Nucleocytoplasmic shuttling of bovine papillomavirus E1 helicase downregulates viral DNA replication in S phase. J Virol 2006; 81:384-94. [PMID: 17035309 PMCID: PMC1797274 DOI: 10.1128/jvi.01170-06] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The papillomavirus E1 protein is essential for the initiation of viral replication. We previously showed that the bovine papillomavirus E1 protein is unstable and becomes resistant to ubiquitin-mediated degradation when tightly bound to cyclin E-cyclin-dependent kinase 2 (Cdk2) before the start of DNA synthesis. However, neither the protection nor the targeted degradation of E1 appears to depend on its phosphorylation by Cdk. Here, we report that Cdk phosphorylation of E1 is also not a prerequisite for the initiation of viral DNA replication either in vitro or in vivo. Nevertheless, we found that phosphorylation of one Cdk site, Ser283, abrogates E1 replicative activity only in a cellular context. We show that this site-specific phosphorylation of E1 drives its export from the nucleus and promotes its continuous nucleocytoplasmic shuttling. In addition, we find that E1 shuttling occurs in S phase, when cyclin A-Cdk2 is activated. E1 interacts with the active cyclin A-Cdk2 complex and is phosphorylated on Ser283 by this kinase. These data suggest that the phosphorylation of E1 on Ser283 is a negative regulatory event that is involved in preventing the amplification of viral DNA during S phase. This finding reveals a novel facet of E1 regulation that could account for the variations of the viral replication capacity during different cell cycle phases, as well as in different stages of the viral cycle.
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Affiliation(s)
- Chiung-Yueh Hsu
- Centre de Recherches de Biochimie Macromoléculaire, CNRS, FRE 2593, IFR122, 1919 Route de Mende, 34 293 Montpellier Cedex 5, France
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Abstract
Carcinoma of the uterine cervix, a leading cause of cancer death in women worldwide, is initiated by infection with high-risk types of human papillomaviruses (HPVs). This review summarizes laboratory studies over the past 20 years that have elucidated the major features of the HPV life cycle, identified the functions of the viral proteins, and clarified the consequences of HPV infection for their host cells. This information has allowed the development of various strategies to prevent or treat infections, including prophylactic vaccination with virus-like particles, therapeutic vaccination against viral proteins expressed in cancer cells, and antiviral approaches to inhibit virus replication, spread, or pathogenesis. These strategies have the potential to cause a dramatic reduction in the incidence of cervical carcinoma and serve as the prototype for comprehensive efforts to combat virus-induced tumors.
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Affiliation(s)
- Daniel DiMaio
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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Schuck S, Stenlund A. Surface mutagenesis of the bovine papillomavirus E1 DNA binding domain reveals residues required for multiple functions related to DNA replication. J Virol 2006; 80:7491-9. [PMID: 16840329 PMCID: PMC1563737 DOI: 10.1128/jvi.00435-06] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The E1 protein from papillomaviruses is a multifunctional protein with complex functions required for the initiation of viral DNA replication. We have performed a surface mutagenesis of the well-characterized E1 DNA binding domain (DBD). We demonstrate that substitutions of multiple residues on the surface of the E1 DBD are defective for DNA replication without affecting the DNA binding activity of the protein. The defects of individual substitutions include failure to form the double trimer that melts the ori and failure to form the double hexamer that unwinds the ori. These results demonstrate that the DBD plays an essential role in multiple DNA replication-related processes apart from DNA binding.
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Affiliation(s)
- Stephen Schuck
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
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46
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Enemark EJ, Joshua-Tor L. Mechanism of DNA translocation in a replicative hexameric helicase. Nature 2006; 442:270-5. [PMID: 16855583 DOI: 10.1038/nature04943] [Citation(s) in RCA: 408] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2006] [Accepted: 06/01/2006] [Indexed: 11/09/2022]
Abstract
The E1 protein of papillomavirus is a hexameric ring helicase belonging to the AAA + family. The mechanism that couples the ATP cycle to DNA translocation has been unclear. Here we present the crystal structure of the E1 hexamer with single-stranded DNA discretely bound within the hexamer channel and nucleotides at the subunit interfaces. This structure demonstrates that only one strand of DNA passes through the hexamer channel and that the DNA-binding hairpins of each subunit form a spiral 'staircase' that sequentially tracks the oligonucleotide backbone. Consecutively grouped ATP, ADP and apo configurations correlate with the height of the hairpin, suggesting a straightforward DNA translocation mechanism. Each subunit sequentially progresses through ATP, ADP and apo states while the associated DNA-binding hairpin travels from the top staircase position to the bottom, escorting one nucleotide of single-stranded DNA through the channel. These events permute sequentially around the ring from one subunit to the next.
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Affiliation(s)
- Eric J Enemark
- W. M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA
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Castella S, Burgin D, Sanders CM. Role of ATP hydrolysis in the DNA translocase activity of the bovine papillomavirus (BPV-1) E1 helicase. Nucleic Acids Res 2006; 34:3731-41. [PMID: 16893956 PMCID: PMC1557793 DOI: 10.1093/nar/gkl554] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The E1 protein of bovine papillomavirus type-1 is the viral replication initiator protein and replicative helicase. Here we show that the C-terminal approximately 300 amino acids of E1, that share homology with members of helicase superfamily 3 (SF3), can act as an autonomous helicase. E1 is monomeric in the absence of ATP but assembles into hexamers in the presence of ATP, single-stranded DNA (ssDNA) or both. A 16 base sequence is the minimum for efficient hexamerization, although the complex protects approximately 30 bases from nuclease digestion, supporting the notion that the DNA is bound within the protein complex. In the absence of ATP, or in the presence of ADP or the non-hydrolysable ATP analogue AMP-PNP, the interaction with short ssDNA oligonucleotides is exceptionally tight (T(1/2) > 6 h). However, in the presence of ATP, the interaction with DNA is destabilized (T(1/2) approximately 60 s). These results suggest that during the ATP hydrolysis cycle an internal DNA-binding site oscillates from a high to a low-affinity state, while protein-protein interactions switch from low to high affinity. This reciprocal change in protein-protein and protein-DNA affinities could be part of a mechanism for tethering the protein to its substrate while unidirectional movement along DNA proceeds.
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Affiliation(s)
| | | | - Cyril M. Sanders
- To whom correspondence should be addressed. Tel: +44 114 2712482; Fax: +44 114 2713892;
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Dao LD, Duffy A, Van Tine BA, Wu SY, Chiang CM, Broker TR, Chow LT. Dynamic localization of the human papillomavirus type 11 origin binding protein E2 through mitosis while in association with the spindle apparatus. J Virol 2006; 80:4792-800. [PMID: 16641272 PMCID: PMC1472045 DOI: 10.1128/jvi.80.10.4792-4800.2006] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Papillomaviral DNA replicates as extrachromosomal plasmids in squamous epithelium. Viral DNA must segregate equitably into daughter cells to persist in dividing basal/parabasal cells. We have previously reported that the viral origin binding protein E2 of human papillomavirus types 11 (HPV-11), 16, and 18 colocalized with the mitotic spindles. In this study, we show the localization of the HPV-11 E2 protein to be dynamic. It colocalized with the mitotic spindles during prophase and metaphase. At anaphase, it began to migrate to the central spindle microtubules, where it remained through telophase and cytokinesis. It was additionally observed in the midbody at cytokinesis. A peptide spanning residues 285 to 308 in the carboxyl-terminal domain of HPV-11 E2 (E2C) is necessary and sufficient to confer localization on the mitotic spindles. This region is conserved in HPV-11, -16, and -18 and bovine papillomavirus type 4 (BPV-4) E2 and is also required for the respective E2C to colocalize with the mitotic spindles. The E2 protein of bovine papillomavirus type 1 is tethered to the mitotic chromosomes via the cellular protein Brd4. However, the HPV-11 E2 protein did not associate with Brd4 during mitosis. Lastly, a chimeric BPV-1 E2C containing the spindle localization domain from HPV-11 E2C gained the ability to localize to the mitotic spindles, whereas the reciprocal chimera lost the ability. We conclude that this region of HPV E2C is critical for localization with the mitotic apparatus, enabling the HPV DNA to sustain persistent infections.
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Affiliation(s)
- Luan D Dao
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294-0005, USA
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Castella S, Bingham G, Sanders CM. Common determinants in DNA melting and helicase-catalysed DNA unwinding by papillomavirus replication protein E1. Nucleic Acids Res 2006; 34:3008-19. [PMID: 16738139 PMCID: PMC1474052 DOI: 10.1093/nar/gkl384] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
E1 and T-antigen of the tumour viruses bovine papillomavirus (BPV-1) and Simian virus 40 (SV40) are the initiator proteins that recognize and melt their respective origins of replication in the initial phase of DNA replication. These proteins then assemble into processive hexameric helicases upon the single-stranded DNA that they create. In T-antigen, a characteristic loop and hairpin structure (the pre-sensor 1β hairpin, PS1βH) project into a central cavity generated by protein hexamerization. This channel undergoes large ATP-dependent conformational changes, and the loop/PS1βH is proposed to form a DNA binding site critical for helicase activity. Here, we show that conserved residues in BPV E1 that probably form a similar loop/hairpin structure are required for helicase activity and also origin (ori) DNA melting. We propose that DNA melting requires the cooperation of the E1 helicase domain (E1HD) and the origin binding domain (OBD) tethered to DNA. One possible mechanism is that with the DNA locked in the loop/PS1βH DNA binding site, ATP-dependent conformational changes draw the DNA inwards in a twisting motion to promote unwinding.
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Affiliation(s)
| | | | - Cyril M. Sanders
- To whom correspondence should be addressed. Tel: +1 14 2712482; Fax: +1 14 2713892;
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Hu Y, Clower RV, Melendy T. Cellular topoisomerase I modulates origin binding by bovine papillomavirus type 1 E1. J Virol 2006; 80:4363-71. [PMID: 16611895 PMCID: PMC1472030 DOI: 10.1128/jvi.80.9.4363-4371.2006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In addition to viral proteins E1 and E2, bovine papillomavirus type 1 (BPV1) depends heavily on host replication machinery for genome duplication. It was previously shown that E1 binds to and recruits cellular replication proteins to the BPV1 origin of replication, including DNA polymerase alpha-primase, replication protein A (RPA), and more recently, human topoisomerase I (Topo I). Here, we show that Topo I specifically stimulates the origin binding of E1 severalfold but has no effect on nonorigin DNA binding. This is highly specific, as binding to nonorigin DNA is not stimulated, and other cellular proteins that bind E1, such as RPA and polymerase alpha-primase, show no such effect. The stimulation of E1's origin binding by Topo I is not synergistic with the stimulation by E2. Although the enhanced origin binding of E1 by Topo I requires ATP and Mg2+ for optimal efficiency, ATP hydrolysis is not required. Using an enzyme-linked immunosorbent assay, we showed that the interaction between E1 and Topo I is decreased in the presence of DNA. Our results suggest that Topo I participates in the initiation of papillomavirus DNA replication by enhancing E1 binding to the BPV1 origin.
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Affiliation(s)
- Yan Hu
- Department of Microbiology and Immunology, University at Buffalo, The School of Medicine and Biomedical Sciences, 213 Biomedical Research Building, 3435 Main Street, Buffalo, New York 14214, USA
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