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Rottenberg JT, Taslim TH, Soto-Ugaldi LF, Martinez-Cuesta L, Martinez-Calejman C, Fuxman Bass JI. Viral cis-regulatory elements as sensors of cellular states and environmental cues. Trends Genet 2024:S0168-9525(24)00108-2. [PMID: 38821843 DOI: 10.1016/j.tig.2024.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/11/2024] [Accepted: 05/13/2024] [Indexed: 06/02/2024]
Abstract
To withstand a hostile cellular environment and replicate, viruses must sense, interpret, and respond to many internal and external cues. Retroviruses and DNA viruses can intercept these cues impinging on host transcription factors via cis-regulatory elements (CREs) in viral genomes, allowing them to sense and coordinate context-specific responses to varied signals. Here, we explore the characteristics of viral CREs, the classes of signals and host transcription factors that regulate them, and how this informs outcomes of viral replication, immune evasion, and latency. We propose that viral CREs constitute central hubs for signal integration from multiple pathways and that sequence variation between viral isolates can rapidly rewire sensing mechanisms, contributing to the variability observed in patient outcomes.
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Affiliation(s)
| | - Tommy H Taslim
- Department of Biology, Boston University, Boston, MA, USA; Molecular and Cellular Biology and Biochemistry Program, Boston University, Boston, MA, USA
| | - Luis F Soto-Ugaldi
- Tri-Institutional Program in Computational Biology and Medicine, New York, NY, USA
| | - Lucia Martinez-Cuesta
- Department of Biology, Boston University, Boston, MA, USA; Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | - Juan I Fuxman Bass
- Department of Biology, Boston University, Boston, MA, USA; Molecular and Cellular Biology and Biochemistry Program, Boston University, Boston, MA, USA.
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2
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Liu X, Sun C, Wang Q, Li P, Zhao T, Li Q. Sp1 Upregulation Bolsters the Radioresistance of Glioblastoma Cells by Promoting Double Strand Breaks Repair. Int J Mol Sci 2023; 24:10658. [PMID: 37445835 PMCID: PMC10342049 DOI: 10.3390/ijms241310658] [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: 05/18/2023] [Revised: 06/08/2023] [Accepted: 06/24/2023] [Indexed: 07/15/2023] Open
Abstract
Radioresistance remains a critical obstacle in the clinical management of glioblastoma (GBM) by radiotherapy. Therefore, it is necessary to explore the molecular mechanisms underlying radioresistance to improve patient response to radiotherapy and increase the treatment efficacy. The present study aimed to elucidate the role of specificity protein 1 (Sp1) in the radioresistance of GBM cells. Different human GBM cell lines and tumor-bearing mice were exposed to ionizing radiation (IR). Cell survival was determined by the colony formation assay. The expression of genes and proteins in the cells and tissues was analyzed by RT-PCR and western blotting, respectively. The γ-H2AX, p-Sp1 and dependent protein kinase catalytic subunit (DNA-PKcs phospho S2056) foci were analyzed by immunofluorescence. Apoptotic rates were measured by flow cytometry. Sp1 was upregulated after IR in vitro and in vivo and knocking down Sp1-sensitized GBM cells to IR. Sp1 activated the DNA-PKcs promoter and increased its expression and activity. Furthermore, the loss of Sp1 delayed double-strand breaks (DSB) repair and increased IR-induced apoptosis of GBM cells. Taken together, IR upregulates Sp1 expression in GBM cells, enhancing the activity of DNA-PKcs and promoting IR-induced DSB repair, thereby leading to increased radioresistance.
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Affiliation(s)
- Xiongxiong Liu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; (X.L.); (T.Z.)
- Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chao Sun
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; (X.L.); (T.Z.)
- Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiqi Wang
- College of Life Science, Northwest Normal University, Lanzhou 730030, China
| | - Ping Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; (X.L.); (T.Z.)
- Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ting Zhao
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; (X.L.); (T.Z.)
- Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiang Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; (X.L.); (T.Z.)
- Key Laboratory of Heavy Ion Radiation Biology and Medicine, Chinese Academy of Sciences, Lanzhou 730000, China
- Key Laboratory of Basic Research on Heavy Ion Radiation Application in Medicine, Lanzhou 730000, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Ivanenko KA, Prassolov VS, Khabusheva ER. Transcription Factor Sp1 in the Expression of Genes Encoding Components of Mapk, JAK/STAT, and PI3K/Akt Signaling Pathways. Mol Biol 2022. [DOI: 10.1134/s0026893322050089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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4
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Feltrin C, Oliveira Simões CM, Marques Sincero TC. Development of a cell-based reporter assay for detection of Human alphaherpesviruses. Mol Cell Probes 2022; 62:101806. [DOI: 10.1016/j.mcp.2022.101806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 02/13/2022] [Accepted: 03/02/2022] [Indexed: 11/28/2022]
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5
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Alekseev O, Donegan WE, Donovan KR, Limonnik V, Azizkhan-Clifford J. HSV-1 Hijacks the Host DNA Damage Response in Corneal Epithelial Cells through ICP4-Mediated Activation of ATM. Invest Ophthalmol Vis Sci 2021; 61:39. [PMID: 32543665 PMCID: PMC7415316 DOI: 10.1167/iovs.61.6.39] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Purpose Herpes simplex virus type I (HSV-1) infection of corneal epithelial cells activates ataxia telangiectasia mutated (ATM), an apical kinase in the host DNA damage response pathway, whose activity is necessary for the progression of lytic HSV-1 infection. The purpose of this study is to investigate the mechanism of ATM activation by HSV-1 in the corneal epithelium, as well as its functional significance. Methods Mechanistic studies were performed in cultured human corneal epithelial cell lines (hTCEpi, HCE), as well as in esophageal (EPC2) and oral (OKF6) cell lines. Transfection-based experiments were performed in HEK293 cells. HSV-1 infection was carried out using the wild-type KOS strain, various mutant strains (tsB7, d120, 7134, i13, n208), and bacterial artificial chromosomes (fHSVΔpac, pM24). Inhibitors of ATM (KU-55933), protein synthesis (cycloheximide), and viral DNA replication (phosphonoacetic acid) were used. Outcomes of infection were assayed using Western blotting, qRT-PCR, immunofluorescence, and comet assay. Results This study demonstrates that HSV-1-mediated ATM activation in corneal epithelial cells relies on the viral immediate early gene product ICP4 and requires the presence of the viral genome in the host nucleus. We show that ATM activation is independent of viral genome replication, the ICP0 protein, and the presence of DNA lesions. Interestingly, ATM activity appears to be necessary at the onset of infection, but dispensable at the later stages. Conclusions This study expands our understanding of HSV-1 virus-host interactions in the corneal epithelium and identifies potential areas of future investigation and therapeutic intervention in herpes keratitis.
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6
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Yun T, Hua J, Ye W, Ni Z, Chen L, Zhang C. The phosphoproteomic responses of duck (Cairna moschata) to classical/novel duck reovirus infections in the spleen tissue. Sci Rep 2020; 10:15315. [PMID: 32943705 PMCID: PMC7499213 DOI: 10.1038/s41598-020-72311-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 08/05/2020] [Indexed: 12/18/2022] Open
Abstract
Duck reovirus (DRV) is a fatal member of the genus Orthoreovirus in the family Reoviridae. The disease caused by DRV leads to huge economic losses to the duck industry. Post-translational modification is an efficient strategy to enhance the immune responses to virus infection. However, the roles of protein phosphorylation in the responses of ducklings to Classic/Novel DRV (C/NDRV) infections are largely unknown. Using a high-resolution LC–MS/MS integrated to highly sensitive immune-affinity antibody method, phosphoproteomes of Cairna moschata spleen tissues under the C/NDRV infections were analyzed, producing a total of 8,504 phosphorylation sites on 2,853 proteins. After normalization with proteomic data, 392 sites on 288 proteins and 484 sites on 342 proteins were significantly changed under the C/NDRV infections, respectively. To characterize the differentially phosphorylated proteins (DPPs), a systematic bioinformatics analyses including Gene Ontology annotation, domain annotation, subcellular localization, and Kyoto Encyclopedia of Genes and Genomes pathway annotation were performed. Two important serine protease system-related proteins, coagulation factor X and fibrinogen α-chain, were identified as phosphorylated proteins, suggesting an involvement of blood coagulation under the C/NDRV infections. Furthermore, 16 proteins involving the intracellular signaling pathways of pattern-recognition receptors were identified as phosphorylated proteins. Changes in the phosphorylation levels of MyD88, NF-κB, RIP1, MDA5 and IRF7 suggested a crucial role of protein phosphorylation in host immune responses of C. moschata. Our study provides new insights into the responses of ducklings to the C/NDRV infections at PTM level.
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Affiliation(s)
- Tao Yun
- Institute of Animal Husbandry and Veterinary Sciences, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Jionggang Hua
- Institute of Animal Husbandry and Veterinary Sciences, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Weicheng Ye
- Institute of Animal Husbandry and Veterinary Sciences, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Zheng Ni
- Institute of Animal Husbandry and Veterinary Sciences, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Liu Chen
- Institute of Animal Husbandry and Veterinary Sciences, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Cun Zhang
- Institute of Animal Husbandry and Veterinary Sciences, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China.
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7
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Wang M, Wu W, Zhang Y, Yao G, Gu B. Rapamycin enhances lytic replication of Epstein-Barr virus in gastric carcinoma cells by increasing the transcriptional activities of immediate-early lytic promoters. Virus Res 2018; 244:173-180. [PMID: 29169830 DOI: 10.1016/j.virusres.2017.11.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 11/18/2017] [Accepted: 11/18/2017] [Indexed: 12/12/2022]
Abstract
Epstein-Barr virus (EBV), a human herpesvirus, is linked to both epithelial and lymphoid malignancies. Induction of EBV reactivation is a potential therapeutic strategy for EBV-associated tumors. In this study, we assessed the effects of rapamycin on EBV reactivation in gastric carcinoma cells. We found that rapamycin upregulated expression of EBV lytic proteins and increased the viral proliferation triggered by the EBV lytic inducer sodium butyrate. Reverse transcription-qPCR, luciferase activity assays, chromatin immunoprecipitation and western blotting were employed to explore the mechanism by which rapamycin promotes EBV reactivation. Our results showed that rapamycin treatment resulted in increased mRNA levels of EBV immediate-early genes. Rapamycin also enhanced the transcriptional activities of the EBV immediate-early lytic promoters Zp and Rp by strengthening Sp1 binding. Repression of the cellular ataxia telangiectasia-mutated/p53 pathway by siRNA-mediated knockdown of the ataxia telangiectasia-mutated gene significantly abrogated virus reactivation by rapamycin/sodium butyrate treatment, indicating that the ataxia telangiectasia-mutated/p53 pathway is involved in rapamycin-promoted EBV reactivation. Taken together, these findings demonstrate that rapamycin might have the potential to enhance the effectiveness of oncolytic viral therapies developed for EBV-associated malignancies.
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MESH Headings
- Ataxia Telangiectasia Mutated Proteins/antagonists & inhibitors
- Ataxia Telangiectasia Mutated Proteins/genetics
- Ataxia Telangiectasia Mutated Proteins/metabolism
- Butyric Acid/pharmacology
- Cell Line, Tumor
- Cell Survival/drug effects
- DNA, Viral/genetics
- DNA, Viral/metabolism
- Gastric Mucosa/drug effects
- Gastric Mucosa/metabolism
- Gastric Mucosa/virology
- Gene Expression Regulation
- Genes, Reporter
- Herpesvirus 4, Human/drug effects
- Herpesvirus 4, Human/genetics
- Herpesvirus 4, Human/growth & development
- Herpesvirus 4, Human/metabolism
- Humans
- Immediate-Early Proteins/agonists
- Immediate-Early Proteins/genetics
- Immediate-Early Proteins/metabolism
- Luciferases/genetics
- Luciferases/metabolism
- Oncolytic Virotherapy/methods
- Promoter Regions, Genetic/drug effects
- Protein Binding
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Sirolimus/pharmacology
- Sp1 Transcription Factor/genetics
- Sp1 Transcription Factor/metabolism
- Transcription, Genetic
- Tumor Suppressor Protein p53/antagonists & inhibitors
- Tumor Suppressor Protein p53/genetics
- Tumor Suppressor Protein p53/metabolism
- Virus Activation/drug effects
- Virus Replication/drug effects
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Affiliation(s)
- Man Wang
- Institute for Translational Medicine, Medical College of Qingdao University, Qingdao, 266021, China.
| | - Wei Wu
- Institute for Translational Medicine, Medical College of Qingdao University, Qingdao, 266021, China
| | - Yinfeng Zhang
- Institute for Translational Medicine, Medical College of Qingdao University, Qingdao, 266021, China
| | - Guoliang Yao
- Department of General Surgery, The First Affiliated Hospital of Henan University of Science and Technology, Luoyang, 471003, China
| | - Bianli Gu
- Henan Key Laboratory of Cancer Epigenetics, Cancer Hospital, The First Affiliated Hospital, College of Clinical Medicine, Medical College of Henan University of Science and Technology, Luoyang, 471003, China
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8
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Hau PM, Tsao SW. Epstein-Barr Virus Hijacks DNA Damage Response Transducers to Orchestrate Its Life Cycle. Viruses 2017; 9:v9110341. [PMID: 29144413 PMCID: PMC5707548 DOI: 10.3390/v9110341] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/30/2017] [Accepted: 11/08/2017] [Indexed: 12/12/2022] Open
Abstract
The Epstein–Barr virus (EBV) is a ubiquitous virus that infects most of the human population. EBV infection is associated with multiple human cancers, including Burkitt’s lymphoma, Hodgkin’s lymphoma, a subset of gastric carcinomas, and almost all undifferentiated non-keratinizing nasopharyngeal carcinoma. Intensive research has shown that EBV triggers a DNA damage response (DDR) during primary infection and lytic reactivation. The EBV-encoded viral proteins have been implicated in deregulating the DDR signaling pathways. The consequences of DDR inactivation lead to genomic instability and promote cellular transformation. This review summarizes the current understanding of the relationship between EBV infection and the DDR transducers, including ATM (ataxia telangiectasia mutated), ATR (ATM and Rad3-related), and DNA-PK (DNA-dependent protein kinase), and discusses how EBV manipulates the DDR signaling pathways to complete the replication process of viral DNA during lytic reactivation.
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Affiliation(s)
- Pok Man Hau
- Department of Anatomical and Cellular Pathology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
| | - Sai Wah Tsao
- School of Biomedical Science, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
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9
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Iwahori S, Kalejta RF. Phosphorylation of transcriptional regulators in the retinoblastoma protein pathway by UL97, the viral cyclin-dependent kinase encoded by human cytomegalovirus. Virology 2017; 512:95-103. [PMID: 28946006 DOI: 10.1016/j.virol.2017.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 01/11/2023]
Abstract
Human cytomegalovirus (HCMV) encodes a viral cyclin-dependent kinase (v-CDK), the UL97 protein. UL97 phosphorylates Rb, p107 and p130, thereby inactivating all three retinoblastoma (Rb) family members. Rb proteins function through regulating the activity of transcription factors to which they bind. Therefore, we examined whether the UL97-mediated regulation of the Rb tumor suppressors also extended to their binding partners. We observed that UL97 phosphorylates LIN52, a component of p107- and p130-assembled transcriptionally repressive DREAM complexes that control transcription during the G0/G1 phases, and the Rb-associated E2F3 protein that activates transcription through G1 and S phases. Intriguingly, we also identified FoxM1B, a transcriptional regulator during the S and G2 phases, as a UL97 substrate. This survey extends the influence of UL97 beyond simply the Rb proteins themselves to their binding partners, as well as past the G1/S transition into later stages of the cell cycle.
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Affiliation(s)
- Satoko Iwahori
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, United States
| | - Robert F Kalejta
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, United States.
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10
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Iwahori S, Umaña AC, VanDeusen HR, Kalejta RF. Human cytomegalovirus-encoded viral cyclin-dependent kinase (v-CDK) UL97 phosphorylates and inactivates the retinoblastoma protein-related p107 and p130 proteins. J Biol Chem 2017; 292:6583-6599. [PMID: 28289097 DOI: 10.1074/jbc.m116.773150] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/09/2017] [Indexed: 01/19/2023] Open
Abstract
The human cytomegalovirus (HCMV)-encoded viral cyclin-dependent kinase (v-CDK) UL97 phosphorylates the retinoblastoma (Rb) tumor suppressor. Here, we identify the other Rb family members p107 and p130 as novel targets of UL97. UL97 phosphorylates p107 and p130 thereby inhibiting their ability to repress the E2F-responsive E2F1 promoter. As with Rb, this phosphorylation, and the rescue of E2F-responsive transcription, is dependent on the L1 LXCXE motif in UL97 and its interacting clefts on p107 and p130. Interestingly, UL97 does not induce the disruption of all p107-E2F or p130-E2F complexes, as it does to Rb-E2F complexes. UL97 strongly interacts with p107 but not Rb or p130. Thus the inhibitory mechanisms of UL97 for Rb family protein-mediated repression of E2F-responsive transcription appear to differ for each of the Rb family proteins. The immediate early 1 (IE1) protein of HCMV also rescues p107- and p130-mediated repression of E2F-responsive gene expression, but it does not induce their phosphorylation and does not disrupt p107-E2F or p130-E2F complexes. The unique regulation of Rb family proteins by HCMV UL97 and IE1 attests to the importance of modulating Rb family protein function in HCMV-infected cells.
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Affiliation(s)
- Satoko Iwahori
- From the Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Angie C Umaña
- From the Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Halena R VanDeusen
- From the Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Robert F Kalejta
- From the Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706
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11
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Measles Virus Infection Inactivates Cellular Protein Phosphatase 5 with Consequent Suppression of Sp1 and c-Myc Activities. J Virol 2015; 89:9709-18. [PMID: 26157124 DOI: 10.1128/jvi.00825-15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 07/02/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Measles virus (MeV) causes several unique syndromes, including transient immunosuppression. To clarify the cellular responses to MeV infection, we previously analyzed a MeV-infected epithelial cell line and a lymphoid cell line by microarray and showed that the expression of numerous genes was up- or downregulated in the epithelial cells. In particular, there was a characteristic comprehensive downregulation of housekeeping genes during late stage infection. To identify the mechanism underlying this phenomenon, we examined the phosphorylation status of transcription factors and kinase/phosphatase activities in epithelial cells after infection. MeV infection inactivated cellular protein phosphatase 5 (PP5) that consequently inactivated DNA-dependent protein kinase, which reduced Sp1 phosphorylation levels, and c-Myc degradation, both of which downregulated the expression of many housekeeping genes. In addition, intracellular accumulation of viral nucleocapsid inactivated PP5 and subsequent downstream responses. These findings demonstrate a novel strategy of MeV during infection, which causes the collapse of host cellular functions. IMPORTANCE Measles virus (MeV) is one of the most important pathogens in humans. We previously showed that MeV infection induces the comprehensive downregulation of housekeeping genes in epithelial cells. By examining this phenomenon, we clarified the molecular mechanism underlying the constitutive expression of housekeeping genes in cells, which is maintained by cellular protein phosphatase 5 (PP5) and DNA-dependent protein kinase. We also demonstrated that MeV targets PP5 for downregulation in epithelial cells. This is the first report to show how MeV infection triggers a reduction in overall cellular functions of infected host cells. Our findings will help uncover unique pathogenicities caused by MeV.
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12
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Iwahori S, Hakki M, Chou S, Kalejta RF. Molecular Determinants for the Inactivation of the Retinoblastoma Tumor Suppressor by the Viral Cyclin-dependent Kinase UL97. J Biol Chem 2015; 290:19666-80. [PMID: 26100623 DOI: 10.1074/jbc.m115.660043] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Indexed: 01/10/2023] Open
Abstract
The retinoblastoma (Rb) tumor suppressor restricts cell cycle progression by repressing E2F-responsive transcription. Cellular cyclin-dependent kinase (CDK)-mediated Rb inactivation through phosphorylation disrupts Rb-E2F complexes, stimulating transcription. The human cytomegalovirus (HCMV) UL97 protein is a viral CDK (v-CDK) that phosphorylates Rb. Here we show that UL97 phosphorylates 11 of the 16 consensus CDK sites in Rb. A cleft within Rb accommodates peptides with the amino acid sequence LXCXE. UL97 contains three such motifs. We determined that the first LXCXE motif (L1) of UL97 and the Rb cleft enhance UL97-mediated Rb phosphorylation. A UL97 mutant with a non-functional L1 motif (UL97-L1m) displayed significantly reduced Rb phosphorylation at multiple sites. Curiously, however, it efficiently disrupted Rb-E2F complexes but failed to relieve Rb-mediated repression of E2F reporter constructs. The HCMV immediate early 1 protein cooperated with UL97-L1m to inactivate Rb in transfection assays, likely indicating that cells infected with a UL97-L1m mutant virus show no defects in growth or E2F-responsive gene expression because of redundant viral mechanisms to inactivate Rb. Our data suggest that UL97 possesses a mechanism to elicit E2F-dependent gene expression distinct from disruption of Rb-E2F complexes and dependent upon both the L1 motif of UL97 and the cleft region of Rb.
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Affiliation(s)
- Satoko Iwahori
- From the Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706 and
| | - Morgan Hakki
- the Division of Infectious Diseases, Oregon Health and Science University and
| | - Sunwen Chou
- the Division of Infectious Diseases, Oregon Health and Science University and Veterans Affairs Portland Health Care System, Portland, Oregon 97239
| | - Robert F Kalejta
- From the Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin 53706 and
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13
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Beishline K, Azizkhan-Clifford J. Sp1 and the 'hallmarks of cancer'. FEBS J 2015; 282:224-58. [PMID: 25393971 DOI: 10.1111/febs.13148] [Citation(s) in RCA: 369] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 09/26/2014] [Accepted: 11/10/2014] [Indexed: 12/19/2022]
Abstract
For many years, transcription factor Sp1 was viewed as a basal transcription factor and relegated to a role in the regulation of so-called housekeeping genes. Identification of Sp1's role in recruiting the general transcription machinery in the absence of a TATA box increased its importance in gene regulation, particularly in light of recent estimates that the majority of mammalian genes lack a TATA box. In this review, we briefly consider the history of Sp1, the founding member of the Sp family of transcription factors. We review the evidence suggesting that Sp1 is highly regulated by post-translational modifications that positively and negatively affect the activity of Sp1 on a wide array of genes. Sp1 is over-expressed in many cancers and is associated with poor prognosis. Targeting Sp1 in cancer treatment has been suggested; however, our review of the literature on the role of Sp1 in the regulation of genes that contribute to the 'hallmarks of cancer' illustrates the extreme complexity of Sp1 functions. Sp1 both activates and suppresses the expression of a number of essential oncogenes and tumor suppressors, as well as genes involved in essential cellular functions, including proliferation, differentiation, the DNA damage response, apoptosis, senescence and angiogenesis. Sp1 is also implicated in inflammation and genomic instability, as well as epigenetic silencing. Given the apparently opposing effects of Sp1, a more complete understanding of the function of Sp1 in cancer is required to validate its potential as a therapeutic target.
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Affiliation(s)
- Kate Beishline
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA, USA
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14
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Hau PM, Deng W, Jia L, Yang J, Tsurumi T, Chiang AKS, Huen MSY, Tsao SW. Role of ATM in the formation of the replication compartment during lytic replication of Epstein-Barr virus in nasopharyngeal epithelial cells. J Virol 2015; 89:652-68. [PMID: 25355892 PMCID: PMC4301132 DOI: 10.1128/jvi.01437-14] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 10/10/2014] [Indexed: 12/27/2022] Open
Abstract
UNLABELLED Epstein-Barr virus (EBV), a type of oncogenic herpesvirus, is associated with human malignancies. Previous studies have shown that lytic reactivation of EBV in latently infected cells induces an ATM-dependent DNA damage response (DDR). The involvement of ATM activation has been implicated in inducing viral lytic gene transcription to promote lytic reactivation. Its contribution to the formation of a replication compartment during lytic reactivation of EBV remains poorly defined. In this study, the role of ATM in viral DNA replication was investigated in EBV-infected nasopharyngeal epithelial cells. We observed that induction of lytic infection of EBV triggers ATM activation and localization of DDR proteins at the viral replication compartments. Suppression of ATM activity using a small interfering RNA (siRNA) approach or a specific chemical inhibitor profoundly suppressed replication of EBV DNA and production of infectious virions in EBV-infected cells induced to undergo lytic reactivation. We further showed that phosphorylation of Sp1 at the serine-101 residue is essential in promoting the accretion of EBV replication proteins at the replication compartment, which is crucial for replication of viral DNA. Knockdown of Sp1 expression by siRNA effectively suppressed the replication of viral DNA and localization of EBV replication proteins to the replication compartments. Our study supports an important role of ATM activation in lytic reactivation of EBV in epithelial cells, and phosphorylation of Sp1 is an essential process downstream of ATM activation involved in the formation of viral replication compartments. Our study revealed an essential role of the ATM-dependent DDR pathway in lytic reactivation of EBV, suggesting a potential antiviral replication strategy using specific DDR inhibitors. IMPORTANCE Epstein-Barr virus (EBV) is closely associated with human malignancies, including undifferentiated nasopharyngeal carcinoma (NPC), which has a high prevalence in southern China. EBV can establish either latent or lytic infection depending on the cellular context of infected host cells. Recent studies have highlighted the importance of the DNA damage response (DDR), a surveillance mechanism that evolves to maintain genome integrity, in regulating lytic EBV replication. However, the underlying molecular events are largely undefined. ATM is consistently activated in EBV-infected epithelial cells when they are induced to undergo lytic reactivation. Suppression of ATM inhibits replication of viral DNA. Furthermore, we observed that phosphorylation of Sp1 at the serine-101 residue, a downstream event of ATM activation, plays an essential role in the formation of viral replication compartments for replication of virus DNA. Our study provides new insights into the mechanism through which EBV utilizes the host cell machinery to promote replication of viral DNA upon lytic reactivation.
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Affiliation(s)
- Pok Man Hau
- Department of Anatomy and Center for Cancer Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR
| | - Wen Deng
- Department of Anatomy and Center for Cancer Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR School of Nursing, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR
| | - Lin Jia
- Department of Anatomy and Center for Cancer Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR
| | - Jie Yang
- Department of Anatomy and Center for Cancer Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR
| | - Tatsuya Tsurumi
- Division of Virology, Aichi Cancer Center Research Institute, Nagoya, Japan
| | - Alan Kwok Shing Chiang
- Department of Pediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR
| | - Michael Shing-Yan Huen
- Genome Stability Research Laboratory, Department of Anatomy and Centre for Cancer Research, The University of Hong Kong, Hong Kong SAR
| | - Sai Wah Tsao
- Department of Anatomy and Center for Cancer Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR
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15
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Alekseev O, Donovan K, Azizkhan-Clifford J. Inhibition of ataxia telangiectasia mutated (ATM) kinase suppresses herpes simplex virus type 1 (HSV-1) keratitis. Invest Ophthalmol Vis Sci 2014; 55:706-15. [PMID: 24370835 DOI: 10.1167/iovs.13-13461] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
PURPOSE Herpes keratitis (HK) remains the leading cause of cornea-derived blindness in the developed world, despite the availability of effective antiviral drugs. Treatment toxicity and the emergence of drug resistance highlight the need for additional therapeutic approaches. This study examined ataxia telangiectasia mutated (ATM), an apical kinase in the host DNA damage response, as a potential new target for the treatment of HK. METHODS Small molecule inhibitor of ATM (KU-55933) was used to treat herpes simplex virus type 1 (HSV-1) infection in three experimental models: (1) in vitro--cultured human corneal epithelial cells, hTCEpi, (2) ex vivo--organotypically explanted human and rabbit corneas, and (3) in vivo--corneal infection in young C57BL/6J mice. Infection productivity was assayed by plaque assay, real-time PCR, Western blot, and disease scoring. RESULTS Robust ATM activation was detected in HSV-1-infected human corneal epithelial cells. Inhibition of ATM greatly suppressed viral replication in cultured cells and in explanted human and rabbit corneas, and reduced the severity of stromal keratitis in mice. The antiviral effect of KU-55933 in combination with acyclovir was additive, and KU-55933 suppressed replication of a drug-resistant HSV-1 strain. KU-55933 caused minimal toxicity, as monitored by clonogenic survival assay and fluorescein staining. CONCLUSIONS This study identifies ATM as a potential target for the treatment of HK. ATM inhibition by KU-55933 reduces epithelial infection and stromal disease severity without producing appreciable toxicity. These findings warrant further investigations into the DNA damage response as an area for therapeutic intervention in herpetic ocular diseases.
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Affiliation(s)
- Oleg Alekseev
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania
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Abstract
Hepatitis C virus (HCV) easily establishes chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). During the progression of HCV infections, reactive oxygen species (ROS) are generated, and these ROS then induce significant DNA damage. The role of ROS in the pathogenesis of HCV infection is still not fully understood. Recently, we found that HCV induced the expression of 3β-hydroxysterol Δ24-reductase (DHCR24). We also found that a HCV responsive region is present in the 5′-flanking genomic promoter region of DHCR24 and the HCV responsive region was characterized as (−167/−140). Moreover, the transcription factor Sp1 was found to bind to this region in response to oxidative stress under the regulation of ataxia telangiectasia mutated (ATM) kinase. Overexpression of DHCR24 impaired p53 activity by suppression of acetylation and increased interaction with MDM2. This impairment of p53 suppressed the hydrogen peroxide-induced apoptotic response in hepatocytes. Thus, a target of oxidative stress in HCV infection is DHCR24 through Sp1, which suppresses apoptotic responses and increases tumorigenicity.
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17
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Transcriptional regulation by post-transcriptional modification—Role of phosphorylation in Sp1 transcriptional activity. Gene 2012; 508:1-8. [DOI: 10.1016/j.gene.2012.07.022] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 05/22/2012] [Accepted: 07/16/2012] [Indexed: 01/05/2023]
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Beishline K, Kelly CM, Olofsson BA, Koduri S, Emrich J, Greenberg RA, Azizkhan-Clifford J. Sp1 facilitates DNA double-strand break repair through a nontranscriptional mechanism. Mol Cell Biol 2012; 32:3790-9. [PMID: 22826432 PMCID: PMC3430196 DOI: 10.1128/mcb.00049-12] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 07/08/2012] [Indexed: 12/18/2022] Open
Abstract
Sp1 is a ubiquitously expressed transcription factor that is phosphorylated by ataxia telangiectasia mutated kinase (ATM) in response to ionizing radiation and H(2)O(2). Here, we show by indirect immunofluorescence that Sp1 phosphorylated on serine 101 (pSp1) localizes to ionizing radiation-induced foci with phosphorylated histone variant γH2Ax and members of the MRN (Mre11, Rad50, and Nbs1) complex. More precise analysis of occupancy of DNA double-strand breaks (DSBs) by chromatin immunoprecipitation (ChIP) shows that Sp1, like Nbs1, resides within 200 bp of DSBs. Using laser microirradiation of cells, we demonstrate that pSp1 is present at DNA DSBs by 7.5 min after induction of damage and remains at the break site for at least 8 h. Depletion of Sp1 inhibits repair of site-specific DNA breaks, and the N-terminal 182-amino-acid peptide, which contains targets of ATM kinase but lacks the zinc finger DNA binding domain, is phosphorylated, localizes to DSBs, and rescues the repair defect resulting from Sp1 depletion. Together, these data demonstrate that Sp1 is rapidly recruited to the region immediately adjacent to sites of DNA DSBs and is required for DSB repair, through a mechanism independent of its sequence-directed transcriptional effects.
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Affiliation(s)
- Kate Beishline
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Crystal M. Kelly
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Beatrix A. Olofsson
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Sravanthi Koduri
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Jacqueline Emrich
- Department of Radiation Oncology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Roger A. Greenberg
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Jane Azizkhan-Clifford
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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19
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Saito M, Kohara M, Tsukiyama-Kohara K. Hepatitis C virus promotes expression of the 3β-hydroxysterol δ24-reductase through Sp1. J Med Virol 2012; 84:733-46. [PMID: 22431021 DOI: 10.1002/jmv.23250] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Hepatitis C virus (HCV) establishes chronic infection, which often causes hepatocellular carcinoma. Overexpression of 3β-hydroxysterol Δ24-reductase (DHCR24) by HCV has been shown to impair the p53-mediated cellular response, resulting in tumorigenesis. In the present study, the molecular mechanism by which HCV promotes the expression of DHCR24 was investigated. A significant increase in DHCR24 mRNA transcription was observed in a cell line expressing complete HCV genome, whereas no significant difference in the expression of DHCR24 was seen in cell lines expressing individual viral proteins. The 5'-flanking genomic region of DHCR24 was characterized to explore the genomic region and host factor(s) involved in the transcriptional regulation of DHCR24. As a result, the HCV response element (-167/-140) was identified, which contains AP-2α, MZF-1, and Sp1 binding motifs. The binding affinity of the host factor to this response element was increased in nuclear extracts from cells infected with HCV and corresponded with augmented affinity of Sp1. Both mithramycin A (Sp1 inhibitor) and small interfering RNA targeting Sp1 prevented the binding of host factors to the response element. Silencing of Sp1 also downregulated the increased expression of DHCR24. The binding affinity of Sp1 to the response element was augmented by oxidative stress, whereas upregulation of DHCR24 in cells expressing HCV was blocked significantly by a reactive oxygen species scavenger. Elevated phosphorylation of Sp1 in response to oxidative stress was mediated by the ATM kinase. Thus, activation of Sp1 by oxidative stress is involved in the promotion of expression of DHCR24 by HCV.
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Affiliation(s)
- Makoto Saito
- Department of Experimental Phylaxiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
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20
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Wuest T, Zheng M, Efstathiou S, Halford WP, Carr DJJ. The herpes simplex virus-1 transactivator infected cell protein-4 drives VEGF-A dependent neovascularization. PLoS Pathog 2011; 7:e1002278. [PMID: 21998580 PMCID: PMC3188529 DOI: 10.1371/journal.ppat.1002278] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 08/02/2011] [Indexed: 01/08/2023] Open
Abstract
Herpes simplex virus-1 (HSV-1) causes lifelong infection affecting between 50 and 90% of the global population. In addition to causing dermal lesions, HSV-1 is a leading cause of blindness resulting from recurrent corneal infection. Corneal disease is characterized by loss of corneal immunologic privilege and extensive neovascularization driven by vascular endothelial growth factor-A (VEGF-A). In the current study, we identify HSV-1 infected cells as the dominant source of VEGF-A during acute infection, and VEGF-A transcription did not require TLR signaling or MAP kinase activation. Rather than being an innate response to the pathogen, VEGF-A transcription was directly activated by the HSV-1 encoded immediate early transcription factor, ICP4. ICP4 bound the proximal human VEGF-A promoter and was sufficient to promote transcription. Transcriptional activation also required cis GC-box elements common to the VEGF-A promoter and HSV-1 early genes. Our results suggest that the neovascularization characteristic of ocular HSV-1 disease is a direct result of HSV-1's major transcriptional regulator, ICP4, and similarities between the VEGF-A promoter and those of HSV-1 early genes. Herpes simplex virus-type 1 is the leading cause of infectious corneal blindness in the industrialized world. Most of the morbidity associated with the virus is due to the host response to episodic reactivation of latent virus. Corneal immunologic privilege is associated with a number of factors including the absence of blood and lymphatic vessels. Conversely, corneal hem (blood)- and lymph-angiogenesis driven by inflammation correlate with the loss of privilege. Neovascularization is a common phenomenon in HSV-1 keratitis that correlates with poor prognosis. We have previously discovered HSV-1 elicits corneal lymphangiogenesis through a unique mechanism involving vascular endothelial growth factor (VEGF)-A independent of that described for other insults including transplantation or bacterial infection. However, the viral-encoded product(s) that elicit host production of VEGF-A is(are) unknown. In this paper, we have identified infected cell protein-4 (ICP4) as the primary virus-encoded product that drives VEGF-A expression. As VEGF-A is involved in driving neovascularization associated with tumor growth and metastasis, proteins that influence transcriptional regulation of VEGF-A may be useful in the development of adjunct therapy for such disparate diseases as cancer and HSV-1 keratitis.
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MESH Headings
- Animals
- Cell Line
- Eye/pathology
- Eye/virology
- Herpesvirus 1, Human/genetics
- Herpesvirus 1, Human/metabolism
- Herpesvirus 1, Human/pathogenicity
- Humans
- Immediate-Early Proteins/genetics
- Immediate-Early Proteins/metabolism
- Keratitis, Herpetic/pathology
- Keratitis, Herpetic/virology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Fluorescence/methods
- Neovascularization, Pathologic/genetics
- Plasmids
- Promoter Regions, Genetic
- Real-Time Polymerase Chain Reaction
- Sequence Analysis, DNA
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcriptional Activation
- Vascular Endothelial Growth Factor A/genetics
- Vascular Endothelial Growth Factor A/metabolism
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Affiliation(s)
- Todd Wuest
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Min Zheng
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Stacey Efstathiou
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - William P. Halford
- Department of Microbiology and Immunology, Southern Illinois University School of Medicine, Springfield, Illinois, United States of America
| | - Daniel J. J. Carr
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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21
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Waby JS, Bingle CD, Corfe BM. Post-translational control of sp-family transcription factors. Curr Genomics 2011; 9:301-11. [PMID: 19471608 PMCID: PMC2685645 DOI: 10.2174/138920208785133244] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 05/14/2008] [Accepted: 05/15/2008] [Indexed: 11/22/2022] Open
Abstract
Sp-family transcription factors are widely expressed in human tissues and involved in the regulation of many cellular processes and response to cellular microenvironment. These responses appear to be mediated by alterations in transcription factor affinity for DNA rather than altered protein level. How might such changes be effected? This review will identify the range of known post-translational modifications (PTMs) of Sp-factors and the sometimes conflicting literature about the roles of PTMs in regulating activity. We will speculate on the interaction between cell environment, chromatin microenvironment and the role of PTM in governing functionality of the proteins and the complexes to which they belong.
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Affiliation(s)
- J S Waby
- School of Medicine and Biomedical Sciences, University of Sheffield, Royal Hallamshire Hospital, Sheffield, S10 2JF, UK
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22
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Millhouse S, Su YH, Zhang X, Wang X, Song BP, Zhu L, Oppenheim E, Fraser NW, Block TM. Evidence that herpes simplex virus DNA derived from quiescently infected cells in vitro, and latently infected cells in vivo, is physically damaged. J Neurovirol 2011; 16:384-98. [PMID: 20874012 DOI: 10.3109/13550284.2010.515651] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Using polymerase chain reaction (PCR) and alkaline gel electrophoresis, the authors show that, compared with DNA derived from virions used to establish infection, herpes simplex virus DNA derived from quiescently infected rat pheochromocytoma (PC12) cells in culture accumulates alkaline-labile lesions. That is, compared with equivalent amounts of virion DNA, viral DNA from nerve growth factor-differentiated long-term infected cells in culture is consistently 3 to 10 times more refractory to amplification by PCR. Despite using equal mole amounts of DNA isolated from quiescently infected cells (determined by quantitative Southern blots), DNA from quiescently infected cells could not be detected by PCR under conditions in which the virion-derived DNA was easily detected. Refractoriness to PCR was confirmed by analysis with a ligation-mediated PCR technique. The refractoriness was not the result of genomic circularization. The refractoriness was, however, related to the time that the quiescently infected cells had been maintained in culture. The refractoriness to PCR was taken as an indication that the viral DNA was damaged. This hypothesis was confirmed by showing that viral DNA from quiescently infected PC12 cells accumulated alkaline-labile DNA lesions, as determined by alkaline gel electrophoresis. The phenomenon was not limited to tissue culture, because viral DNA derived from the ganglia of latently infected mice is also 3 to 10 times more refractory to amplification than are equivalent amounts of virion-derived genomes. Taken together, these results represent the first evidence that herpes simplex virus DNA is physically damaged as a function of long-term infection. Implications for viral reactivation and pathogenesis are discussed.
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Affiliation(s)
- Scott Millhouse
- Drexel Institute for Biotechnology and Virology Research and Department of Microbiology and Immunology, College of Medicine, Drexel University, Doylestown, Pennsylvania 18901-2697, USA
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23
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Zhu H, Fan Y, Jiang H, Shen J, Qi H, Mei R, Shao J. Response of human DNA polymerase ι promoter to N-methyl-N'-nitro-N-nitrosoguanidine. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2010; 29:79-86. [PMID: 21787586 DOI: 10.1016/j.etap.2009.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 10/28/2009] [Accepted: 11/02/2009] [Indexed: 05/31/2023]
Abstract
Human Pol ι is a highly distributed, low-fidelity DNA polymerase lacking intrinsic exonuclease proofreading activity, thus its effects are strictly regulated. We predicted and cloned the promoter region of the human POLI gene. Successively, by transfection of deletion constructs of the POLI promoter, we demonstrated that the regions -848/-408 and -30/+215 contained positive regulatory elements, and the region +215/+335 had proximal promoter activity. Overexpression of Sp1 significantly increased the transcriptional activity of the promoter, and mutation of the Sp1 site reversed Sp1-induced promoter transactivation. Quantitative RT-PCR showed that POLI mRNA expression was up-regulated in human amnion FL cells treated by the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Reporter gene assays demonstrated that MNNG also significantly increased the transcriptional activity of the predicted promoter (-848/+335) and the proximal promoter (+215/+335). However, the promoter with the Sp1 site mutation had no response to MNNG treatment, suggesting that Sp1 plays an important role in the transcriptional regulation of the POLI gene stimulated by MNNG. Our data suggest that abnormal regulation of Pol ι may be involved in the mutagenesis and carcinogenesis induced by environmental chemicals.
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Affiliation(s)
- Huifang Zhu
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou 310058, PR China
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24
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Wuest TR, Carr DJJ. VEGF-A expression by HSV-1-infected cells drives corneal lymphangiogenesis. ACTA ACUST UNITED AC 2009; 207:101-15. [PMID: 20026662 PMCID: PMC2812544 DOI: 10.1084/jem.20091385] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Inflammatory lymphangiogenesis plays a crucial role in the development of inflammation and transplant rejection. The mechanisms of inflammatory lymphangiogenesis during bacterial infection, toll-like receptor ligand administration, and wound healing are well characterized and depend on ligands for the vascular endothelial grow factor receptor (VEGFR) 3 that are produced by infiltrating macrophages. But inflammatory lymphangiogenesis in nonlymphoid tissues during chronic viral infection is unstudied. Herpes simplex virus 1 (HSV-1) infection of the cornea is a leading cause of blindness and depends on aberrant host immune responses to antigen within the normally immunologically privileged cornea. We report that corneal HSV-1 infection drives lymphangiogenesis and that corneal lymphatics persist past the resolution of infection. The mechanism of HSV-1–induced lymphangiogenesis was distinct from the described mechanisms of inflammatory lymphangiogenesis. HSV-1–elicited lymphangiogenesis was strictly dependent on VEGF-A/VEGFR-2 signaling but not on VEGFR-3 ligands. Macrophages played no role in the induction of lymphangiogenesis and were not a detectable source of VEGF-A. Rather, using VEGF-A reporter transgenic mice, we have identified infected epithelial cells as the primary source of VEGF-A during HSV-1 infection. Our results indicate that HSV-1 directly induces vascularization of the cornea through up-regulation of VEGF-A expression.
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Affiliation(s)
- Todd R Wuest
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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26
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Iwahori S, Yasui Y, Kudoh A, Sato Y, Nakayama S, Murata T, Isomura H, Tsurumi T. Identification of phosphorylation sites on transcription factor Sp1 in response to DNA damage and its accumulation at damaged sites. Cell Signal 2008; 20:1795-803. [DOI: 10.1016/j.cellsig.2008.06.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Accepted: 06/13/2008] [Indexed: 10/22/2022]
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27
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Olofsson BA, Kelly CM, Kim J, Hornsby SM, Azizkhan-Clifford J. Phosphorylation of Sp1 in response to DNA damage by ataxia telangiectasia-mutated kinase. Mol Cancer Res 2008; 5:1319-30. [PMID: 18171990 DOI: 10.1158/1541-7786.mcr-07-0374] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Sp1, a transcription factor that regulates expression of a wide array of essential genes, contains two SQ/TQ cluster domains, which are characteristic of ATM kinase substrates. ATM substrates are transducers and effectors of the DNA damage response, which involves sensing damage, checkpoint activation, DNA repair, and/or apoptosis. A role for Sp1 in the DNA damage response is supported by our findings: Activation of ATM induces Sp1 phosphorylation with kinetics similar to H2AX; inhibition of ATM activity blocks Sp1 phosphorylation; depletion of Sp1 sensitizes cells to DNA damage and increases the frequency of double strand breaks. We have identified serine 101 as a critical site phosphorylated by ATM; Sp1 with serine 101 mutated to alanine (S101A) is not significantly phosphorylated in response to damage and cannot restore increased sensitivity to DNA damage of cells depleted of Sp1. Together, these data show that Sp1 is a novel ATM substrate that plays a role in the cellular response to DNA damage.
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Affiliation(s)
- Beatrix A Olofsson
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, USA
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28
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Sampath P, Deluca NA. Binding of ICP4, TATA-binding protein, and RNA polymerase II to herpes simplex virus type 1 immediate-early, early, and late promoters in virus-infected cells. J Virol 2008; 82:2339-49. [PMID: 18094162 PMCID: PMC2258917 DOI: 10.1128/jvi.02459-07] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Accepted: 12/13/2007] [Indexed: 11/20/2022] Open
Abstract
The binding of herpes simplex virus type 1 ICP4, TATA-binding protein (TBP), and RNA polymerase II (polII) to the promoter regions of representative immediate-early (IE) (ICP0), early (E) (thymidine kinase [tk]), and late (L) (glycoprotein C [gC]) genes on the viral genome was examined as a function of time postinfection, viral DNA replication, cis-acting sites for TFIID in the tk and gC promoters, and genetic background of ICP4. The binding of TBP and polII to the IE ICP0 promoter was independent of the presence of ICP4, whereas the binding of TBP and polII to the tk and gC promoters occurred only when ICP4 also bound to the promoters, suggesting that the presence of ICP4 at the promoters of E and L genes in virus-infected cells is crucial for the formation of transcription complexes on these promoters. When the TATA box of the tk promoter or the initiator element (INR) of the gC promoter was mutated, a reduction in the amount of TBP and polII binding was observed. However, a reduction in the amount of ICP4 binding to the promoters was also observed, suggesting that the binding of TBP-containing complexes and ICP4 is cooperative. The binding of ICP4, TBP, and polII was also observed on the gC promoter at early times postinfection or when DNA synthesis was inhibited, suggesting that transcription complexes may be formed early on L promoters and that additional events or proteins are required for expression. The ability to form these early complexes on the gC promoter required the DNA-binding domain but in addition required the carboxyl-terminal 524 amino acids of ICP4, which is missing the virus n208. This region was not required to form TBP- and polII-containing complexes on the tk promoter. n208 activates E but not L genes during viral infection. These data suggest that a region of ICP4 may differentiate between forming TBP- and polII-containing complexes on E and L promoters.
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Affiliation(s)
- Padmavathi Sampath
- E1257 Biomedical Science Tower, Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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