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Wu CC, Chen MS, Lee TY, Cheng YJ, Tsou HH, Huang TS, Cho DY, Chen JY. Screening and identification of emodin as an EBV DNase inhibitor to prevent its biological functions. Virol J 2023; 20:148. [PMID: 37443068 DOI: 10.1186/s12985-023-02107-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
BACKGROUND The Epstein-Barr virus (EBV) is a prevalent oncovirus associated with a variety of human illnesses. BGLF5, an EBV DNase with alkaline nuclease (AN) activity, plays important roles in the viral life cycle and progression of human malignancies and has been suggested as a possible diagnostic marker and target for cancer therapy. Methods used conventionally for the detection of AN activity, radioactivity-based nuclease activity assay and DNA digestion detection by gel electrophoresis, are not suitable for screening AN inhibitors; the former approach is unsafe, and the latter is complicated. In the present study, a fluorescence-based nuclease activity assay was used to screen several natural compounds and identify an EBV DNase inhibitor. RESULTS Fluorescence-based nuclease activity assays, in which the DNA substrate is labelled with PicoGreen dye, are cheaper, safer, and easier to perform. Herein, the results of the fluorescence-based nuclease activity assay were consistent with the results of the two conventional methods. In addition, the PicoGreen-labelling method was applied for the biochemical characterisation of viral nucleases. Using this approach, we explored EBV DNase inhibitors. After several rounds of screening, emodin, an anthraquinone derivative, was found to possess significant anti-EBV DNase activity. We verified the efficacy of emodin using the conventional DNA-cleavage assay. Furthermore, using comet assay and micronucleus formation detection, we confirmed that emodin can inhibit DNase-induced DNA damage and genomic instability. Additionally, emodin treatment inhibited EBV production. CONCLUSIONS Using a PicoGreen-mediated nuclease activity assay, we successfully demonstrated that emodin has the potential to inhibit EBV DNase nuclease activity. Emodin also inhibits EBV DNase-related biological functions, suggesting that it is a potential inhibitor of EBV DNase.
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Affiliation(s)
- Chung-Chun Wu
- Translational Cell Therapy Center, Department of Medical Research, China Medical University Hospital, No. 2, Yude Rd., North Dist, Taichung City, 40447, Taiwan.
| | - Mei-Shu Chen
- National Institute of Cancer Research, National Health Research Institutes, No.35, Keyan Road, Zhunan Town, Miaoli County, Taiwan
| | - Ting-Ying Lee
- Translational Cell Therapy Center, Department of Medical Research, China Medical University Hospital, No. 2, Yude Rd., North Dist, Taichung City, 40447, Taiwan
| | - Yu-Jhen Cheng
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan, Taiwan
| | - Hsiao-Hui Tsou
- Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Taiwan
| | - Tze-Sing Huang
- National Institute of Cancer Research, National Health Research Institutes, No.35, Keyan Road, Zhunan Town, Miaoli County, Taiwan
| | - Der-Yang Cho
- Translational Cell Therapy Center, Department of Medical Research, China Medical University Hospital, No. 2, Yude Rd., North Dist, Taichung City, 40447, Taiwan
| | - Jen-Yang Chen
- National Institute of Cancer Research, National Health Research Institutes, No.35, Keyan Road, Zhunan Town, Miaoli County, Taiwan.
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Casco A, Johannsen E. EBV Reactivation from Latency Is a Degrading Experience for the Host. Viruses 2023; 15:726. [PMID: 36992435 PMCID: PMC10054251 DOI: 10.3390/v15030726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/06/2023] [Accepted: 03/08/2023] [Indexed: 03/15/2023] Open
Abstract
During reactivation from latency, gammaherpesviruses radically restructure their host cell to produce virion particles. To achieve this and thwart cellular defenses, they induce rapid degradation of cytoplasmic mRNAs, suppressing host gene expression. In this article, we review mechanisms of shutoff by Epstein-Barr virus (EBV) and other gammaherpesviruses. In EBV, canonical host shutoff is accomplished through the action of the versatile BGLF5 nuclease expressed during lytic reactivation. We explore how BGLF5 induces mRNA degradation, the mechanisms by which specificity is achieved, and the consequences for host gene expression. We also consider non-canonical mechanisms of EBV-induced host shutoff. Finally, we summarize the limitations and barriers to accurate measurements of the EBV host shutoff phenomenon.
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Affiliation(s)
- Alejandro Casco
- Department of Oncology, McArdle Laboratory for Cancer Research, University of Wisconsin, Madison, WI 53705, USA
| | - Eric Johannsen
- Department of Oncology, McArdle Laboratory for Cancer Research, University of Wisconsin, Madison, WI 53705, USA
- Department of Medicine, Division of Infectious Diseases, University of Wisconsin, Madison, WI 53705, USA
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