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Feng Y, Gao GF. Towards our understanding of SARS-CoV, an emerging and devastating but quickly conquered virus. Comp Immunol Microbiol Infect Dis 2007; 30:309-27. [PMID: 17640731 PMCID: PMC7112560 DOI: 10.1016/j.cimid.2007.05.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Accepted: 05/16/2007] [Indexed: 12/30/2022]
Abstract
Severe acute respiratory syndrome (SARS) is a newly emerging infectious disease caused by a novel coronavirus (SARS-CoV), which has overwhelmed more than 30 countries claiming nearly 8400 cases with over 800 fatalities. Thanks to the unprecedented international collaboration, the whole-genomes of SARS-CoVs were successfully deciphered shortly after the identification of the causative pathogen for outbreak of SARS in southern China, in 2003. Hitherto, the SARS-CoV, as a viral paradigm of emerging infectious entities, has been extensively studied that has ranged from epidemiology, molecular virology/immunology to structural genomics. Also, several lines of breakthroughs have been record-brokenly obtained, that included the finding of ACE2, a functional receptor for the SARS-CoV, solution of the 3CL(pro) structure, a first crystal structure of SARS-related macromolecules, revealing of bats as natural reservoirs for SARS-like viruses and the possible involvement of civet cats in the SARS emergence. This review intends to outline the major progress in the journey of SARS-related exploration, by emphasizing those inaugurated studies with milestone-like significance contributed by Chinese research groups.
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Affiliation(s)
- Youjun Feng
- Center for Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China
- Graduate University, Chinese Academy of Sciences, Beijing 100049, China
| | - George F. Gao
- Center for Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China
- Corresponding author. Tel.: +86 10 64807688; fax: +86 10 64807365.
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Abstract
abstract: Severe acute respiratory syndrome (SARS) is a newly found infectious disease that is caused by a novel human coronavirus, SARS coronavirus (SARS‐CoV). Because the mortality rate of SARS patients is very high, understanding the pathological mechanisms of SARS not only in vivo but in vitro is important for the prevention of SARS. Activation of signaling pathways caused by SARS‐CoV infection leads to the phosphorylation and activation of downstream molecules. Two conflicting cellular programs, apoptosis to eliminate virus‐infected cells and survival to delay apoptosis by producing antiviral cytokines, occur in SARS patients. Recent studies regarding SARS and SARS‐CoV have clarified that activation of mitogen‐activated protein kinases (MAPKs) plays important roles in upregulation of cytokine expression and apoptosis both in vitro and in vivo. Both Akt and p38 MAPK are keys for determination of cell survival or death in SARS‐CoV‐infected cells in vitro. Agents being developed to target these signaling cascades may be important for the design of anti‐SARS‐CoV drugs. This review highlights recent progress regarding SARS‐CoV biology, especially signal transduction in SARS‐CoV‐infected cells.
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Affiliation(s)
- T Mizutani
- Department of Virology 1, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo, Japan.
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53
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Cheng G, Li Y, Xie B, Yang C, Zhou J. Cloning and identification of lpsH, a novel gene playing a fundamental role in symbiotic nitrogen fixation of Mesorhizobium huakuii. Curr Microbiol 2007; 54:371-5. [PMID: 17486406 DOI: 10.1007/s00284-006-0471-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2006] [Accepted: 02/08/2007] [Indexed: 10/23/2022]
Abstract
Mesorhizobium huakuii 7653R forms a symbiotic relationship with Astragalus sinicus to produce nitrogen-fixing root nodules under nitrogen-limiting conditions. By screening its transposon-inserted mutant library, a mutation in the lpsH gene was found to form pseudonodules on A. sinicus. Its effect was further confirmed by double-crossover mutant HK242. DNA sequence analysis revealed that the lpsH gene encodes a deduced protein of 397 amino acids with a predicted molecular mass of 43.6 kD. LpsH contains a putative signal peptide, 11 transmembrane helices, and an O-antigen polymerase domain, which locates on the periplasmic membrane and is necessary to lipopolysaccharide synthesis. Plant studies showed that the lpsH gene mutant formed ineffective nodules, and this symbiotic phenotype was linked to abnormal nodule development.
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Affiliation(s)
- Guojun Cheng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, 430070, Wuhan, China
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54
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Gu J, Korteweg C. Pathology and pathogenesis of severe acute respiratory syndrome. THE AMERICAN JOURNAL OF PATHOLOGY 2007; 170:1136-47. [PMID: 17392154 PMCID: PMC1829448 DOI: 10.2353/ajpath.2007.061088] [Citation(s) in RCA: 394] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Severe acute respiratory syndrome (SARS) is an emerging infectious viral disease characterized by severe clinical manifestations of the lower respiratory tract. The pathogenesis of SARS is highly complex, with multiple factors leading to severe injury in the lungs and dissemination of the virus to several other organs. The SARS coronavirus targets the epithelial cells of the respiratory tract, resulting in diffuse alveolar damage. Several organs/cell types may be infected in the course of the illness, including mucosal cells of the intestines, tubular epithelial cells of the kidneys, neurons of the brain, and several types of immune cells, and certain organs may suffer from indirect injury. Extensive studies have provided a basic understanding of the pathogenesis of this disease. In this review we describe the most significant pathological features of SARS, explore the etiological factors causing these pathological changes, and discuss the major pathogenetic mechanisms. The latter include dysregulation of cytokines/chemokines, deficiencies in the innate immune response, direct infection of immune cells, direct viral cytopathic effects, down-regulation of lung protective angiotensin converting enzyme 2, autoimmunity, and genetic factors. It seems that both abnormal immune responses and injury to immune cells may be key factors in the pathogenesis of this new disease.
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Affiliation(s)
- Jiang Gu
- Professor and Chairman, Department of Pathology, Dean, School of Medical Sciences, Director, Infectious Disease Center, Peking (Beijing) University, 38 Xueyuan Rd., 100083 Beijing, China.
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55
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Induction of apoptosis by the severe acute respiratory syndrome coronavirus 7a protein is dependent on its interaction with the Bcl-XL protein. J Virol 2007. [PMID: 17428862 DOI: 10.1128/jvi.00090‐07] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The severe acute respiratory syndrome coronavirus (SARS-CoV) 7a protein, which is not expressed by other known coronaviruses, can induce apoptosis in various cell lines. In this study, we show that the overexpression of Bcl-XL, a prosurvival member of the Bcl-2 family, blocks 7a-induced apoptosis, suggesting that the mechanism for apoptosis induction by 7a is at the level of or upstream from the Bcl-2 family. Coimmunoprecipitation experiments showed that 7a interacts with Bcl-XL and other prosurvival proteins (Bcl-2, Bcl-w, Mcl-1, and A1) but not with the proapoptotic proteins (Bax, Bak, Bad, and Bid). A good correlation between the abilities of 7a deletion mutants to induce apoptosis and to interact with Bcl-XL was observed, suggesting that 7a triggers apoptosis by interfering directly with the prosurvival function of Bcl-XL. Interestingly, amino acids 224 and 225 within the C-terminal transmembrane domain of Bcl-XL are essential for the interaction with the 7a protein, although the BH3 domain of Bcl-XL also contributes to this interaction. In addition, fractionation experiments showed that 7a colocalized with Bcl-XL at the endoplasmic reticulum as well as the mitochondria, suggesting that they may form complexes in different membranous compartments.
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Tan YX, Tan THP, Lee MJR, Tham PY, Gunalan V, Druce J, Birch C, Catton M, Fu NY, Yu VC, Tan YJ. Induction of apoptosis by the severe acute respiratory syndrome coronavirus 7a protein is dependent on its interaction with the Bcl-XL protein. J Virol 2007; 81:6346-55. [PMID: 17428862 PMCID: PMC1900074 DOI: 10.1128/jvi.00090-07] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The severe acute respiratory syndrome coronavirus (SARS-CoV) 7a protein, which is not expressed by other known coronaviruses, can induce apoptosis in various cell lines. In this study, we show that the overexpression of Bcl-XL, a prosurvival member of the Bcl-2 family, blocks 7a-induced apoptosis, suggesting that the mechanism for apoptosis induction by 7a is at the level of or upstream from the Bcl-2 family. Coimmunoprecipitation experiments showed that 7a interacts with Bcl-XL and other prosurvival proteins (Bcl-2, Bcl-w, Mcl-1, and A1) but not with the proapoptotic proteins (Bax, Bak, Bad, and Bid). A good correlation between the abilities of 7a deletion mutants to induce apoptosis and to interact with Bcl-XL was observed, suggesting that 7a triggers apoptosis by interfering directly with the prosurvival function of Bcl-XL. Interestingly, amino acids 224 and 225 within the C-terminal transmembrane domain of Bcl-XL are essential for the interaction with the 7a protein, although the BH3 domain of Bcl-XL also contributes to this interaction. In addition, fractionation experiments showed that 7a colocalized with Bcl-XL at the endoplasmic reticulum as well as the mitochondria, suggesting that they may form complexes in different membranous compartments.
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Affiliation(s)
- Ying-Xim Tan
- Collaborative Anti-Viral Research Group, Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673, Republic of Singapore
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57
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Chan CM, Ma CW, Chan WY, Chan HYE. The SARS-Coronavirus Membrane protein induces apoptosis through modulating the Akt survival pathway. Arch Biochem Biophys 2007; 459:197-207. [PMID: 17306213 PMCID: PMC7094499 DOI: 10.1016/j.abb.2007.01.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 12/20/2006] [Accepted: 01/05/2007] [Indexed: 01/12/2023]
Abstract
A number of viral gene products are capable of triggering apoptotic cell death through interfering with cellular signaling cascades, including the Akt kinase pathway. In this study, the pro-apoptotic role of the SARS-CoV Membrane (M) structural protein is described. We found that the SARS-CoV M protein induced apoptosis in both HEK293T cells and transgenic Drosophila. We further showed that M protein-induced apoptosis involved mitochondrial release of cytochrome c protein, and could be suppressed by caspase inhibitors. Over-expression of M caused a dominant rough-eye phenotype in adult Drosophila. By performing a forward genetic modifier screen, we identified phosphoinositide-dependent kinase-1 (PDK-1) as a dominant suppressor of M-induced apoptotic cell death. Both PDK-1 and Akt kinases play essential roles in the cell survival signaling pathway. Altogether, our data show that SARS-CoV M protein induces apoptosis through the modulation of the cellular Akt pro-survival pathway and mitochondrial cytochrome c release.
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Affiliation(s)
- Chak-Ming Chan
- Laboratory of Drosophila Research, Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
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58
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Liu Z, Wang Z, Liu Y, Dong W, Qi Y. Analysis of proteins that interact with nucleocapsid protein of SARS-CoV using 15-mer phage-displayed library. CHINESE SCIENCE BULLETIN-CHINESE 2007; 52:2072-2080. [PMID: 32214725 PMCID: PMC7088746 DOI: 10.1007/s11434-007-0303-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Accepted: 04/16/2007] [Indexed: 12/16/2022]
Abstract
Analysis of proteins that interact with N protein of SARS-CoV using 15-mer phage-displayed library will help to explore the virus pathogenesis and to develop new drugs and vaccines against SARS. In this study, we cloned, expressed and purified N protein of SARS-CoV. This 46-kD N protein was verified by SDS-PAGE and Western-blot. Then, the peptides binding-specific to N protein were identified using 15-mer phage-displayed library. Surprisingly, all of the 89 clones from monoclonal ELISA were positive (S/N>2.1) and the result was further confirmed experimentally once again. Six N protein-binding peptides, designated separately as SNA1, SNA2, SNA4, SNA5, SNA9 and SNG11, were selected for sequencing. Sequence analysis suggested that SNA5 shared approximatively 100% sequence identity to SNA4, SNA2, SNA9 and SNA1. In addition, the binding specificity of the 15-mer peptides with the SARS-CoV N protein was further demonstrated by blocking ELISA using the synthetical 15-mer peptide according to the deduced amino acid sequence of SNA5. Also, the deduced amino sequence of SNA5 was compared with proteins in translated database using the tblastx program, and the results showed that the proteins with the highest homology were Ubiquinol-cytochrome c reductase iron-sulfur subunits (UCRI or UQCR), otherwise known as the Rieske iron-sulfur proteins (RISP). Notablely, in the [2Fe-2S] redox centre of UCRI, there were 6 residues [GGW(Y)F(Y)CP] compatible to the residues (position 2→7, GGWFCP7) of the NH2-terminal of the 15-mer peptide, which indicated higher binding specificity between the N protein of SARS-CoV and the redox centre of UCRI to some extent. Here, the possible molecular mechanisms of SARS-CoV N protein in the pathogenesis of SARS are discussed.
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Affiliation(s)
- ZhengXue Liu
- State Key Laboratory of Virology, College of Life Science, Wuhan University, Wuhan, 430072 China
- Biology Department, Chongqing Three Gorges University, Chongqing, 404000 China
| | - ZhanHui Wang
- State Key Laboratory of Virology, College of Life Science, Wuhan University, Wuhan, 430072 China
| | - YingLe Liu
- State Key Laboratory of Virology, College of Life Science, Wuhan University, Wuhan, 430072 China
| | - Wei Dong
- State Key Laboratory of Virology, College of Life Science, Wuhan University, Wuhan, 430072 China
| | - YiPeng Qi
- State Key Laboratory of Virology, College of Life Science, Wuhan University, Wuhan, 430072 China
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59
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Ruggieri A, Di Trani L, Gatto I, Franco M, Vignolo E, Bedini B, Elia G, Buonavoglia C. Canine coronavirus induces apoptosis in cultured cells. Vet Microbiol 2006; 121:64-72. [PMID: 17254720 PMCID: PMC7117493 DOI: 10.1016/j.vetmic.2006.12.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Revised: 12/01/2006] [Accepted: 12/13/2006] [Indexed: 11/21/2022]
Abstract
Canine coronavirus (CCoV) is widespread in dogs in several countries and causes mild enteric illness evolving to severe enteritis in young pups. In in vitro cultures canine coronaviruses generally induce extensive cell death, however nature of the events leading to cell death remains largely unknown. We analysed the induction of cytopathic effect by CCoV in a canine fibrosarcoma cell line (A-72) in order to characterize the apoptotic effect in homologous cell system. Following CCoV infection A-72 cell line, which is permissive to CCoV, showed reduced growth rate, as detected by MTT assay, a standard colorimetric assay for measuring cellular proliferation, and underwent to apoptotic death. Starting from 24 h after CCoV infection, cells morphology appeared dramatically changed, with cells rounding and detachment from culture surface. Morphologic and biochemical features of apoptosis, such as blebbing of the plasma membrane, translocation of phosphatidilserine to cell surface and annexin V positive staining, nuclear fragmentation, apoptotic bodies formation and DNA laddering, were detected in CCoV-infected cells. Propidium iodide staining of infected culture indicated the appearance of hypodiploid DNA peak corresponding to apoptotic cell population. Commonly to other animal coronavirus infection caspase-3 is likely to contribute to the execution phase of apoptosis induced by CCoV in A-72 cells since we found activation of enzymatic activity as well as procaspase-3 activating cleavage. Apoptotic death of infected cells is detrimental as it causes cell and tissue destruction as well as inflammatory responses. Therefore in the case of CCoV associated gastroenteritis, apoptosis of epithelial mucosa cells may be responsible for pathology induced by CCoV infection.
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Affiliation(s)
- A Ruggieri
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore Sanità, Viale Regina Elena 299, 00161 Rome, Italy
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McBride CE, Li J, Machamer CE. The cytoplasmic tail of the severe acute respiratory syndrome coronavirus spike protein contains a novel endoplasmic reticulum retrieval signal that binds COPI and promotes interaction with membrane protein. J Virol 2006; 81:2418-28. [PMID: 17166901 PMCID: PMC1865919 DOI: 10.1128/jvi.02146-06] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Like other coronaviruses, severe acute respiratory syndrome coronavirus (SARS CoV) assembles at and buds into the lumen of the endoplasmic reticulum (ER)-Golgi intermediate compartment (ERGIC). Accumulation of the viral envelope proteins at this compartment is a prerequisite for virus assembly. Previously, we reported the identification of a dibasic motif (KxHxx) in the cytoplasmic tail of the SARS CoV spike (S) protein that was similar to a canonical dilysine ER retrieval signal. Here we demonstrate that this motif is a novel and functional ER retrieval signal which reduced the rate of traffic of the full-length S protein through the Golgi complex. The KxHxx motif also partially retained two different reporter proteins in the ERGIC region and reduced their rates of trafficking, although the motif was less potent than the canonical dilysine signal. The dibasic motif bound the coatomer complex I (COPI) in an in vitro binding assay, suggesting that ER retrieval may contribute to the accumulation of SARS CoV S protein near the virus assembly site for interaction with other viral structural proteins. In support of this, we found that the dibasic motif on the SARS S protein was required for its localization to the ERGIC/Golgi region when coexpressed with SARS membrane (M) protein. Thus, the cycling of SARS S through the ER-Golgi system may be required for its incorporation into assembling virions in the ERGIC.
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Affiliation(s)
- Corrin E McBride
- Department of Cell Biology, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA
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61
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Fan Z, Zhuo Y, Tan X, Zhou Z, Yuan J, Qiang B, Yan J, Peng X, Gao GF. SARS-CoV nucleocapsid protein binds to hUbc9, a ubiquitin conjugating enzyme of the sumoylation system. J Med Virol 2006; 78:1365-73. [PMID: 16998888 PMCID: PMC7167196 DOI: 10.1002/jmv.20707] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SARS‐CoV is a newly identified coronavirus (CoV) that causes severe acute respiratory syndrome (SARS). The SARS‐CoV nucleocapsid (N) protein is an important structural and functional protein. To identify cellular proteins that interact with the SARS‐CoV N protein and to elucidate the possible involvement of N protein in SARS‐CoV pathogenesis, a human lymphocyte cDNA library was screened using a yeast two‐hybrid system assay. hUbc9, a ubiquitin conjugating enzyme of sumoylation system, was found to interact specifically with the N protein, implying the post‐translational sumoylation of the N protein. Mapping studies localized the critical N sequences for this interaction to amino acids 170–210, which includes the SR‐rich motif. However, the consensus motif of sumoylation GK62EE in the N protein is not responsible for binding to hUbc9. Mutations of hUbc9 at the enzyme active site C93A or C93S severely impair the interaction with the N protein. The two proteins were also shown to colocalize in the cytoplasm of the transfected 293T cells. This is the first report demonstrating the interaction of hUbc9 with a structural protein of plus‐strand RNA viruses, indicating a new drug target for SARS‐CoV. J. Med. Virol. 78:1365–1373, 2006. © 2006 Wiley‐Liss, Inc.
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Affiliation(s)
- Zheng Fan
- Center for Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yue Zhuo
- Center for Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- Department of Biochemistry, Anhui Agricultural University, Hefei, China
| | - Xinyu Tan
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zhi Zhou
- Center for Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jiangang Yuan
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Boqin Qiang
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jinghua Yan
- Center for Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xiaozhong Peng
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - George F. Gao
- Center for Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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Wang H, Rao S, Jiang C. Molecular pathogenesis of severe acute respiratory syndrome. Microbes Infect 2006; 9:119-26. [PMID: 17142081 PMCID: PMC7110495 DOI: 10.1016/j.micinf.2006.06.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Accepted: 06/21/2006] [Indexed: 01/23/2023]
Abstract
The global outbreak in 2002–2003 of severe acute respiratory syndrome (SARS) posed a serious threat to public health and had a significant impact on socioeconomic stability. Although the global outbreak of SARS has been contained, there are serious concerns over its re-emergence and bioterrorism potential, and up to date, no specific treatment exists for this disease. Here we review the progress of studies on the pathogenesis of the disease, in particular, studies on the molecular level.
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Affiliation(s)
| | | | - Chengyu Jiang
- Corresponding author. Tel: +86 10 6529 6908; fax: +86 10 6278 0741.
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63
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Zhou M, Xu D, Li X, Li H, Shan M, Tang J, Wang M, Wang FS, Zhu X, Tao H, He W, Tien P, Gao GF. Screening and identification of severe acute respiratory syndrome-associated coronavirus-specific CTL epitopes. THE JOURNAL OF IMMUNOLOGY 2006; 177:2138-45. [PMID: 16887973 DOI: 10.4049/jimmunol.177.4.2138] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Severe acute respiratory syndrome (SARS) is a highly contagious and life-threatening disease that emerged in China in November 2002. A novel SARS-associated coronavirus was identified as its principal etiologic agent; however, the immunopathogenesis of SARS and the role of special CTLs in virus clearance are still largely uncharacterized. In this study, potential HLA-A*0201-restricted spike (S) and nucleocapsid protein-derived peptides were selected from an online database and screened for potential CTL epitopes by in vitro refolding and T2 cell-stabilization assays. The antigenicity of nine peptides which could refold with HLA-A*0201 molecules was assessed with an IFN-gamma ELISPOT assay to determine the capacity to stimulate CTLs from PBMCs of HLA-A2(+) SARS-recovered donors. A novel HLA-A*0201-restricted decameric epitope P15 (S411-420, KLPDDFMGCV) derived from the S protein was identified and found to localize within the angiotensin-converting enzyme 2 receptor-binding region of the S1 domain. P15 could significantly enhance the expression of HLA-A*0201 molecules on the T2 cell surface, stimulate IFN-gamma-producing CTLs from the PBMCs of former SARS patients, and induce specific CTLs from P15-immunized HLA-A2.1 transgenic mice in vivo. Furthermore, significant P15-specific CTLs were induced from HLA-A2.1-transgenic mice immunized by a DNA vaccine encoding the S protein; suggesting that P15 was a naturally processed epitope. Thus, P15 may be a novel SARS-associated coronavirus-specific CTL epitope and a potential target for characterization of virus control mechanisms and evaluation of candidate SARS vaccines.
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MESH Headings
- Animals
- Cells, Cultured
- Coronavirus Nucleocapsid Proteins
- Enzyme-Linked Immunosorbent Assay
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/isolation & purification
- Epitopes, T-Lymphocyte/metabolism
- HLA-A Antigens/biosynthesis
- HLA-A Antigens/metabolism
- HLA-A2 Antigen
- Humans
- Interferon-gamma/metabolism
- Intracellular Fluid/immunology
- Intracellular Fluid/metabolism
- Intracellular Fluid/virology
- Leukocytes, Mononuclear/immunology
- Leukocytes, Mononuclear/virology
- Lymphocyte Activation/immunology
- Membrane Glycoproteins/administration & dosage
- Membrane Glycoproteins/immunology
- Membrane Glycoproteins/isolation & purification
- Membrane Glycoproteins/metabolism
- Mice
- Mice, Transgenic
- Nucleocapsid Proteins/immunology
- Nucleocapsid Proteins/isolation & purification
- Nucleocapsid Proteins/metabolism
- Peptide Fragments/administration & dosage
- Peptide Fragments/immunology
- Peptide Fragments/isolation & purification
- Peptide Fragments/metabolism
- Protein Binding/immunology
- Severe acute respiratory syndrome-related coronavirus/immunology
- Severe acute respiratory syndrome-related coronavirus/isolation & purification
- Severe acute respiratory syndrome-related coronavirus/metabolism
- Spike Glycoprotein, Coronavirus
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
- T-Lymphocytes, Cytotoxic/virology
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/immunology
- Viral Envelope Proteins/administration & dosage
- Viral Envelope Proteins/immunology
- Viral Envelope Proteins/isolation & purification
- Viral Envelope Proteins/metabolism
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Affiliation(s)
- Minghai Zhou
- Center for Molecular Immunology and Center for Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences (CAS), Beijing, The People's Republic of China
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Khan S, Fielding BC, Tan TH, Chou CF, Shen S, Lim SG, Hong W, Tan YJ. Over-expression of severe acute respiratory syndrome coronavirus 3b protein induces both apoptosis and necrosis in Vero E6 cells. Virus Res 2006; 122:20-7. [PMID: 16965829 PMCID: PMC7114230 DOI: 10.1016/j.virusres.2006.06.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Revised: 05/24/2006] [Accepted: 06/07/2006] [Indexed: 12/21/2022]
Abstract
The genome of the severe acute respiratory syndrome coronavirus encodes for eight accessory viral proteins with no known homologues in other coronaviruses. One of these is the 3b protein, which is encoded by the second open reading frame in subgenomic RNA 3 and contains 154 amino acids. Here, a detailed time-course study was performed to compare the apoptosis and necrosis profiles induced by full-length 3b, a 3b mutant that was deleted by 30 amino acids from the C terminus (3bΔ124-154) and the classical apoptosis inducer, Bax. Our results showed that Vero E6 cells transfected with a construct for expressing 3b underwent necrosis as early as 6 h after transfection and underwent simultaneous necrosis and apoptosis at later time-points. At all the time-points analysed, the apoptosis induced by the expression of 3b was less than the level induced by Bax but the level of necrosis was comparable. The 3bΔ124-154 mutant behaves in a similar manner indicating that the localization of the 3b protein does not seems to be important for the cell-death pathways since full-length 3b is localized predominantly to the nucleolus, while the mutant is found to be concentrated in the peri-nuclear regions. To our knowledge, this is the first report of the induction of necrosis by a SARS-CoV protein.
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Affiliation(s)
| | | | | | | | | | | | | | - Yee-Joo Tan
- Corresponding author. Tel.: +65 65869625; fax: +65 67791117.
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65
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Zhao G, Shi SQ, Yang Y, Peng JP. M and N proteins of SARS coronavirus induce apoptosis in HPF cells. Cell Biol Toxicol 2006; 22:313-22. [PMID: 16845612 PMCID: PMC7087820 DOI: 10.1007/s10565-006-0077-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Accepted: 04/12/2006] [Indexed: 01/05/2023]
Abstract
BACKGROUND SARS-associated coronavirus (SARS-CoV) induced cell apoptosis and its structural proteins may play a role in this process. OBJECTIVES To determine whether the structural proteins M and N of SARS-CoV induce apoptosis. STUDY DESIGN We investigated human pulmonary fibroblast (HPF) cells, were transfected with plasmids containing the M or N gene, by TdT-mediated dUTP nick end labeling (TUNEL), Hoechst 33342 staining for nuclei, and observation of morphology. RESULTS We found that in the absence of serum about 16.34% of cells transfected by pcDNA3.1-M and 21.72% of N-transfected cells showed typical apoptotic characteristics, significantly different from mock-transfected cells (only 6.23%, p<0.01). Furthermore, the cells that were co-transfected with M and N proteins showed more obvious phenomena of cell death (about 36.03%). There was a statistical significance between M-transfected cells and co-transfected cells (p<0.01), and a remarkable difference between N-transfected cells and co-transfected cells (p<0.01). CONCLUSIONS The results show that M and N proteins of SARS-CoV can induce apoptosis of HPF cells. Co-transfection of M and N enhances the induction of apoptosis by M or N alone, which also suggests that the structural proteins of SARS-CoV may play an important role not only in the process of invasion but also in the pathogenetic process in cells.
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Affiliation(s)
- Gang Zhao
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100080 China
- Graduate University of the Chinese Academy of Sciences, Beijing, China
| | - Shu-Qun Shi
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100080 China
- Graduate University of the Chinese Academy of Sciences, Beijing, China
| | - Ying Yang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100080 China
| | - Jing-Pian Peng
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100080 China
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66
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Shin GC, Chung YS, Kim IS, Cho HW, Kang C. Preparation and characterization of a novel monoclonal antibody specific to severe acute respiratory syndrome-coronavirus nucleocapsid protein. Virus Res 2006; 122:109-18. [PMID: 16942813 PMCID: PMC7114302 DOI: 10.1016/j.virusres.2006.07.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 07/03/2006] [Accepted: 07/10/2006] [Indexed: 11/24/2022]
Abstract
Severe acute respiratory syndrome-coronavirus nucleocapsid (SARS-CoV N) protein has been found to be important to the processes related to viral pathogenesis, such as virus replication, interference of the cell process and modulation of host immune response; detection of the antigen has been used for the early diagnosis of infection. We have used recombinant N protein expressed in insect cells to generate 17 mAbs directed against this protein. We selected five mAbs that could be used in various diagnostic assays, and all of these mAbs recognized linear epitopes. Three IgG2b mAbs were recognized within the N-terminus of N protein, whereas the epitope of two IgG1 mAbs localized within the C-terminus. These mAbs were found to have significant reactivity with both non-phosphorylated and phosphorylated N proteins, which resulted in high reactivity with native N protein in virus-infected cells; however, they did not show cross-reactivity with human coronavirus. Therefore, these results suggested that these mAbs would be useful in the development of various diagnostic kits and in future studies of SARS-CoV pathology.
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Affiliation(s)
| | | | | | | | - Chun Kang
- Corresponding author. Tel.: +82 2 380 1501; fax: +82 2 389 2014.
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67
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Chan PKS, Tang JW, Hui DSC. SARS: clinical presentation, transmission, pathogenesis and treatment options. Clin Sci (Lond) 2006; 110:193-204. [PMID: 16411895 DOI: 10.1042/cs20050188] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SARS (severe acute respiratory syndrome) appeared as the first emerging infectious disease of this century. It is fortunate that the culprit virus can be grown without much difficulty from a commonly used cell line, allowing an unlimited supply of isolates for further molecular studies and leading to the development of sensitive diagnostic assays. How the virus has successfully jumped the species barrier is still a mystery. The superspreading events that occurred within hospital, hotel and high-density housing estate opens a new chapter in the mechanisms and routes of virus transmission. The old practice of quarantine proved to be still useful in controlling the global outbreak. Despite all the available sophisticated tests, alertness with early recognition by healthcare workers and prompt isolation of suspected cases is still the most important step for containing the spread of the infection. Although the rapidly evolving outbreak did not allow the conducting of systematic clinical trails to evaluate treatment options, the accumulated experience on managing SARS patients will improve the clinical outcome should SARS return. Although SARS led to more than 700 deaths worldwide, the lessons learnt have prepared healthcare systems worldwide to face future emerging and re-emerging infections.
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Affiliation(s)
- Paul K S Chan
- Department of Microbiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China.
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68
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Lai CW, Chan ZR, Yang DG, Lo WH, Lai YK, Chang MDT, Hu YC. Accelerated induction of apoptosis in insect cells by baculovirus-expressed SARS-CoV membrane protein. FEBS Lett 2006; 580:3829-34. [PMID: 16797548 PMCID: PMC7094299 DOI: 10.1016/j.febslet.2006.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2006] [Accepted: 06/01/2006] [Indexed: 01/08/2023]
Abstract
It has been shown that severe acute respiratory syndrome‐associated coronavirus (SARS‐CoV) 3a and 7a proteins, but not membrane (M) protein, induce apoptosis in mammalian cells. Upon expression of SARS‐CoV M protein using the baculovirus/insect cell expression system, however, we found that the expressed M protein triggered accelerated apoptosis in insect cells, as characterized by rapid cell death, elevated cytotoxicity, cell shrinkage, nuclear condensation and DNA fragmentation. Conversely, the M protein expressed in mammalian cells did not induce apoptosis. This is the first report describing the induction of apoptosis by SARS‐CoV M protein in animal cells and possible implications are discussed.
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Affiliation(s)
- Chia-Wei Lai
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Zun-Ren Chan
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Ding-Gang Yang
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
- Institute of Biotechnology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Wen-Hsin Lo
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Yiu-Kay Lai
- Institute of Biotechnology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Margaret Dah-Tsyr Chang
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Yu-Chen Hu
- Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
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69
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Lin CW, Lin KH, Hsieh TH, Shiu SY, Li JY. Severe acute respiratory syndrome coronavirus 3C-like protease-induced apoptosis. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2006; 46:375-80. [PMID: 16553810 PMCID: PMC7110344 DOI: 10.1111/j.1574-695x.2006.00045.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Accepted: 10/06/2005] [Indexed: 01/30/2023]
Abstract
The pathogenesis of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is an important issue for the treatment and prevention of severe acute respiratory syndrome. Recently, SARS-CoV has been demonstrated to induce cell apoptosis in Vero-E6 cells. The possible role of SARS-CoV 3C-like protease (3CLpro) in virus-induced apoptosis is characterized in this study. Growth arrest and apoptosis via caspase-3 and caspase-9 activities were demonstrated in SARS-CoV 3CLpro -expressing human promonocyte cells. The fluorescence intensity of dihydrorhodamine 123 staining indicated that cellular reactive oxygen species were markedly increased in SARS-CoV 3CLpro -expressing cells. Moreover, in vivo signalling pathway assay indicated that 3CLpro increased the activation of the nuclear factor-kappa B-dependent reporter, but inhibited activator protein-1-dependent transcription. This finding is likely to be responsible for virus-induced apoptotic signalling.
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Affiliation(s)
- Cheng-Wen Lin
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan.
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70
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Yang Y, Xiong Z, Zhang S, Yan Y, Nguyen J, Ng B, Lu H, Brendese J, Yang F, Wang H, Yang XF. Bcl-xL inhibits T-cell apoptosis induced by expression of SARS coronavirus E protein in the absence of growth factors. Biochem J 2006; 392:135-43. [PMID: 16048439 PMCID: PMC1317672 DOI: 10.1042/bj20050698] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
One of the hallmark findings in patients suffering from SARS (severe acute respiratory syndrome) is lymphopenia, which is the result of massive lymphocyte death. SARS-CoV (SARS coronavirus), a novel coronavirus that has been etiologically associated with SARS cases, is homologous with MHV (murine hepatitis coronavirus), and MHV small envelope E protein is capable of inducing apoptosis. We hypothesized that SARS-CoV encodes a small envelope E protein that is homologous with MHV E protein, thus inducing T-cell apoptosis. To test this hypothesis, a cDNA encoding SARS-CoV E protein was created using whole gene synthesis. Our results showed that SARS-CoV E protein induced apoptosis in the transfected Jurkat T-cells, which was amplified to higher apoptosis rates in the absence of growth factors. However, apoptosis was inhibited by overexpressed antiapoptotic protein Bcl-xL. Moreover, we found that SARS-CoV E protein interacted with Bcl-xL in vitro and endogenous Bcl-xL in vivo and that Bcl-xL interaction with SARS-CoV E protein was mediated by BH3 (Bcl-2 homology domain 3) of Bcl-xL. Finally, we identified a novel BH3-like region located in the C-terminal cytosolic domain of SARS-CoV E protein, which mediates its binding to Bcl-xL. These results demonstrate, for the first time, a novel molecular mechanism of T-cell apoptosis that contributes to the SARS-CoV-induced lymphopenia observed in most SARS patients.
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Affiliation(s)
- Yu Yang
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Zeyu Xiong
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Sheng Zhang
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Yan Yan
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Justin Nguyen
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Bernard Ng
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Huifang Lu
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - John Brendese
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Fan Yang
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Hong Wang
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
- †Section of Atherosclerosis and Lipoprotein Research, Baylor College of Medicine, Houston, TX 77030, U.S.A
| | - Xiao-Feng Yang
- *Department of Medicine, Laboratory of Immunopathology, Biology of Inflammation Center, Baylor College of Medicine, Houston, TX 77030, U.S.A
- ‡Department of Immunology, Baylor College of Medicine, Houston, TX 77030, U.S.A
- To whom correspondence should be addressed, at Department of Medicine, Biology of Inflammation Center, Baylor College of Medicine (email )
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71
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Kopecky-Bromberg SA, Martinez-Sobrido L, Palese P. 7a protein of severe acute respiratory syndrome coronavirus inhibits cellular protein synthesis and activates p38 mitogen-activated protein kinase. J Virol 2006; 80:785-93. [PMID: 16378980 PMCID: PMC1346853 DOI: 10.1128/jvi.80.2.785-793.2006] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
It was recently shown that the 7a protein of severe acute respiratory syndrome coronavirus induces biochemical changes associated with apoptosis. In this study, the mechanism by which the 7a protein induces apoptosis was examined. The 7a protein was tested for the ability to inhibit cellular gene expression because several proapoptotic viral proteins with this function have previously been identified. 7a protein inhibited expression of luciferase from an mRNA construct that specifically measures translation, whereas inhibitors of transcription and nucleocytoplasmic transport did not. The inhibition of translation and other cellular processes of gene expression have been associated with the induction of a stress response in cells. Western blot analysis using phosphospecific antibodies indicated that 7a protein activated p38 mitogen-activated protein kinase (MAPK), but not c-Jun N-terminal protein kinase/stress-activated protein kinase. Taken together, these data indicate that the induction of apoptosis by the 7a protein may be related to its ability to inhibit cellular translation and activate p38 MAPK.
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72
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Perlman S, Holmes KV. HCoV-OC43-induced apoptosis of murine neuronal cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 581:473-8. [PMID: 17037580 PMCID: PMC7123252 DOI: 10.1007/978-0-387-33012-9_84] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Stanley Perlman
- Department of Pediatrics, University of Iowa, 52242 Iowa City, IA USA
| | - Kathryn V. Holmes
- Department of Microbiology, University of Colorado Health Sciences Center at Fitzsimons, 80045-8333 Aurora, CO USA
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73
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7a protein of severe acute respiratory syndrome coronavirus inhibits cellular protein synthesis and activates p38 mitogen-activated protein kinase. J Virol 2005. [PMID: 16378980 DOI: 10.1128/jvi.80.2.785‐793.2006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
It was recently shown that the 7a protein of severe acute respiratory syndrome coronavirus induces biochemical changes associated with apoptosis. In this study, the mechanism by which the 7a protein induces apoptosis was examined. The 7a protein was tested for the ability to inhibit cellular gene expression because several proapoptotic viral proteins with this function have previously been identified. 7a protein inhibited expression of luciferase from an mRNA construct that specifically measures translation, whereas inhibitors of transcription and nucleocytoplasmic transport did not. The inhibition of translation and other cellular processes of gene expression have been associated with the induction of a stress response in cells. Western blot analysis using phosphospecific antibodies indicated that 7a protein activated p38 mitogen-activated protein kinase (MAPK), but not c-Jun N-terminal protein kinase/stress-activated protein kinase. Taken together, these data indicate that the induction of apoptosis by the 7a protein may be related to its ability to inhibit cellular translation and activate p38 MAPK.
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74
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Chow KY, Yeung YS, Hon CC, Zeng F, Law KM, Leung FC. Adenovirus-mediated expression of the C-terminal domain of SARS-CoV spike protein is sufficient to induce apoptosis in Vero E6 cells. FEBS Lett 2005; 579:6699-704. [PMID: 16310778 PMCID: PMC7094440 DOI: 10.1016/j.febslet.2005.10.065] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Revised: 10/18/2005] [Accepted: 10/25/2005] [Indexed: 02/08/2023]
Abstract
The pro-apoptotic properties of severe acute respiratory syndrome coronavirus (SARS-CoV) structural proteins were studied in vitro. By monitoring apoptosis indicators including chromatin condensation, cellular DNA fragmentation and cell membrane asymmetry, we demonstrated that the adenovirus-mediated over-expression of SARS-CoV spike (S) protein and its C-terminal domain (S2) induce apoptosis in Vero E6 cells in a time- and dosage-dependent manner, whereas the expression of its N-terminal domain (S1) and other structural proteins, including envelope (E), membrane (M) and nucleocapsid (N) protein do not. These findings suggest a possible role of S and S2 protein in SARS-CoV induced apoptosis and the molecular pathogenesis of SARS.
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Affiliation(s)
- Ken Y.C. Chow
- Department of Zoology, Kadoorie Biological Science Building, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Yin Shan Yeung
- Department of Zoology, Kadoorie Biological Science Building, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Chung Chau Hon
- Department of Zoology, Kadoorie Biological Science Building, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Fanya Zeng
- Department of Zoology, Kadoorie Biological Science Building, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Ka Man Law
- Department of Zoology, Kadoorie Biological Science Building, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Frederick C.C. Leung
- Department of Zoology, Kadoorie Biological Science Building, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
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75
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Poon LL, Leung CS, Chan KH, Yuen KY, Guan Y, Peiris JS. Recurrent mutations associated with isolation and passage of SARS coronavirus in cells from non-human primates. J Med Virol 2005; 76:435-40. [PMID: 15977248 PMCID: PMC7166449 DOI: 10.1002/jmv.20379] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Four clinical isolates of SARS coronavirus were serially passaged in two primate cell lines (FRhK4 and Vero E6). Viral genetic sequences encoding for structural proteins and open reading frames 6–8 were determined in the original clinical specimen, the initial virus isolate (passage 0) and at passages 5, 10, and 15. After 15 passages, a total of 15 different mutations were identified and 12 of them were non‐synonymous mutations. Seven of these mutations were recurrent mutation and all located at the spike, membrane, and Orf 8a protein encoding sequences. Mutations in the membrane protein and a deletion in ORF 6–8 were already observed in passage 0, suggesting these amino acid substitutions are important in the adaptation of the virus isolate in primate cell culture. A mutation in the spike gene (residue 24079) appeared to be unique to adaptation in FRhK4 cells. It is important to be aware of cell culture associated mutations when interpreting data on molecular evolution of SARS coronavirus. J. Med. Virol. 76:435–440, 2005. © 2005 Wiley‐Liss, Inc.
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Affiliation(s)
- Leo L.M. Poon
- Department of Microbiology, University of Hong Kong, Pokfulam, Hong Kong
| | - Cynthia S.W. Leung
- Department of Microbiology, University of Hong Kong, Pokfulam, Hong Kong
| | - Kwok H. Chan
- Department of Microbiology, University of Hong Kong, Pokfulam, Hong Kong
| | - Kwok Y. Yuen
- Department of Microbiology, University of Hong Kong, Pokfulam, Hong Kong
| | - Yi Guan
- Department of Microbiology, University of Hong Kong, Pokfulam, Hong Kong
| | - Joseph S.M. Peiris
- Department of Microbiology, University of Hong Kong, Pokfulam, Hong Kong
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76
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Ren L, Yang R, Guo L, Qu J, Wang J, Hung T. Apoptosis induced by the SARS-associated coronavirus in Vero cells is replication-dependent and involves caspase. DNA Cell Biol 2005; 24:496-502. [PMID: 16101347 DOI: 10.1089/dna.2005.24.496] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The pathogenesis of the severe acute respiratory syndrome (SARS), a newly emerging life-threatening disease in humans, remains unknown. It is believed that the modulation of apoptosis is relevant to diseases that are caused by various viruses. To examine potential apoptotic mechanisms related to SARS, we investigated features of apoptosis induced by the SARS-associated coronavirus (SARS-CoV) in host cells. The results indicated that the SARS-CoV-induced apoptosis in Vero cells in a virus replication-dependent manner. Additionally, the downregulation of Bcl-2, the activation of casapse 3, as well as the upregulation of Bax were detected, suggesting the involvement of the caspase family and the activation of the mitochondrial signaling pathway. Although there is a positive correlation between apoptosis and virus replication, the latter is not significantly blocked by treatment with the caspase inhibitor z-DEVD-FMK. These preliminary data provide important information on both the pathogenesis and potential antiviral targets of SARS-CoV.
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Affiliation(s)
- Lili Ren
- National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republicof China
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77
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Wong SA, Chen Y, Chan CM, Chan CM, Chan PK, Chui Y, Fung KP, Waye MM, Tsui SK, Chan HE. In vivo functional characterization of the SARS-Coronavirus 3a protein in Drosophila. Biochem Biophys Res Commun 2005; 337:720-9. [PMID: 16212942 PMCID: PMC7117541 DOI: 10.1016/j.bbrc.2005.09.098] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Accepted: 09/16/2005] [Indexed: 11/30/2022]
Abstract
The Severe Acute Respiratory Syndrome-Coronavirus (SARS-CoV) 3a locus encodes a 274 a.a. novel protein, and its expression has been confirmed in SARS patients. To study functional roles of 3a, we established a transgenic fly model for the SARS-CoV 3a gene. Misexpression of 3a in Drosophila caused a dominant rough eye phenotype. Using a specific monoclonal antibody, we demonstrated that the 3a protein displayed a punctate cytoplasmic localization in Drosophila as in SARS-CoV-infected cells. We provide genetic evidence to support that 3a is functionally related to clathrin-mediated endocytosis. We further found that 3a misexpression induces apoptosis, which could be modulated by cellular cytochrome c levels and caspase activity. From a forward genetic screen, 78 dominant 3a modifying loci were recovered and the identity of these modifiers revealed that the severity of the 3a-induced rough eye phenotype depends on multiple cellular processes including gene transcriptional regulation.
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Affiliation(s)
- S.L. Alan Wong
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Yiwei Chen
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Chak Ming Chan
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - C.S. Michael Chan
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Paul K.S. Chan
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Y.L. Chui
- Clinical Immunology Unit, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Kwok Pui Fung
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Mary M.Y. Waye
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Stephen K.W. Tsui
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - H.Y. Edwin Chan
- Laboratory of Drosophila Research, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Corresponding author. Fax: +852 2603 7732.
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78
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Bordi L, Castilletti C, Falasca L, Ciccosanti F, Calcaterra S, Rozera G, Di Caro A, Zaniratti S, Rinaldi A, Ippolito G, Piacentini M, Capobianchi MR. Bcl-2 inhibits the caspase-dependent apoptosis induced by SARS-CoV without affecting virus replication kinetics. Arch Virol 2005; 151:369-77. [PMID: 16155806 PMCID: PMC7086587 DOI: 10.1007/s00705-005-0632-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Accepted: 08/02/2005] [Indexed: 01/20/2023]
Abstract
Vero cells transfected with either neo- or bcl-2-plasmid were infected with SARS-CoV at a high multiplicity of infection. Apoptosis appeared after the onset of CPE and completion of virus replication, and could be prevented by Bcl-2 expression. Apoptosis is likely mediated by the mitochondrial pathway, as demonstrated by its inhibition using Bcl-2, and by the activation of the caspase cascade, resulting in PARP cleavage. Prevention of apoptosis did not affect susceptibility to infection, kinetics and extent of viral replication and release, thus implying that apoptosis is not involved in facilitating release and/or dissemination of SARS-CoV in Vero cells.
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Affiliation(s)
- L Bordi
- Laboratory of Virology, National Institute for Infectious Diseases INMI L. Spallanzani, Rome, Italy
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79
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Yamate M, Yamashita M, Goto T, Tsuji S, Li YG, Warachit J, Yunoki M, Ikuta K. Establishment of Vero E6 cell clones persistently infected with severe acute respiratory syndrome coronavirus. Microbes Infect 2005; 7:1530-40. [PMID: 16269264 PMCID: PMC7110502 DOI: 10.1016/j.micinf.2005.05.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2005] [Revised: 05/07/2005] [Accepted: 05/16/2005] [Indexed: 12/28/2022]
Abstract
Little information is available on persistent infection of severe acute respiratory syndrome (SARS) coronavirus (CoV). In this study, we established persistent infection of SARS-CoV in the Vero E6 cell line. Acute infection of Vero E6 with SARS-CoV produced a lytic infection with characteristic rounding cytopathic effects (CPE) and the production of a large number of infectious particles in the culture fluid within 3 days post-infection. Upon subsequent culturing of the remaining adherent cells, the cells gradually proliferated and recovered normal morphology similar to that of the parental cells, and continued to produce large numbers of infectious viral particles during the observation period of 5 months. Among a total of 87 cell clones obtained from the persistently infected Vero E6, only four cell clones (named #13, #18, #21, and #34) were positive for viral RNA. Clones #13, #18, and #34 shifted to viral RNA-negative during subsequent cultures, while #21 continuously produced infectious particles at a high rate. The SARS-CoV receptor, angiotensin-converting enzyme 2, was almost completely down regulated from the cell surface of persistently infected cells. Western blot analysis as well as electron microscopy indicated that the ratios of spike to nucleocapsid protein in clone #21 as well as its parental persistently infected cells were lower than that in the cells in the acute phase of infection. These Vero E6 cells persistently infected with SARS-CoV may be useful for clarifying the mechanism of the persistent infection and also for elucidating the possible pathophysiologic significance of such long-term maintenance of this virus.
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Affiliation(s)
- Masanobu Yamate
- Department of Virology, Research Institute for Microbial Diseases, Osaka University, Suita, Japan
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80
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Law PTW, Wong CH, Au TCC, Chuck CP, Kong SK, Chan PKS, To KF, Lo AWI, Chan JYW, Suen YK, Chan HYE, Fung KP, Waye MMY, Sung JJY, Lo YMD, Tsui SKW. The 3a protein of severe acute respiratory syndrome-associated coronavirus induces apoptosis in Vero E6 cells. J Gen Virol 2005; 86:1921-1930. [PMID: 15958670 DOI: 10.1099/vir.0.80813-0] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
An outbreak of severe acute respiratory syndrome (SARS) occurred in China and the first case emerged in mid-November 2002. The aetiological agent of this disease was found to be a previously unknown coronavirus, SARS-associated coronavirus (SARS-CoV). The detailed pathology of SARS-CoV infection and the host response to the viral infection are still not known. The 3a gene encodes a non-structural viral protein, which is predicted to be a transmembrane protein. In this study, it was shown that the 3a protein was expressed in the lungs and intestinal tissues of SARS patients and that the protein localized to the endoplasmic reticulum in 3a-transfected monkey kidney Vero E6 cells. In vitro experiments of chromatin condensation and DNA fragmentation suggested that the 3a protein may trigger apoptosis. These data showed that overexpression of a single SARS-CoV protein can induce apoptosis in vitro.
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Affiliation(s)
- Patrick T W Law
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
- Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Chi-Hang Wong
- Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Thomas C C Au
- Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Chi-Pang Chuck
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Siu-Kai Kong
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Paul K S Chan
- Department of Microbiology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Ka-Fai To
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Anthony W I Lo
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Judy Y W Chan
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Yick-Keung Suen
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - H Y Edwin Chan
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Kwok-Pui Fung
- The Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Mary M Y Waye
- The Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Joseph J Y Sung
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
- Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Y M Dennis Lo
- Department of Chemical Pathology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
- Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
| | - Stephen K W Tsui
- The Croucher Laboratory for Human Genomics, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
- Centre for Emerging Infectious Diseases, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China
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81
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Timani KA, Liao Q, Ye L, Zeng Y, Liu J, Zheng Y, Ye L, Yang X, Lingbao K, Gao J, Zhu Y. Nuclear/nucleolar localization properties of C-terminal nucleocapsid protein of SARS coronavirus. Virus Res 2005; 114:23-34. [PMID: 15992957 PMCID: PMC7114095 DOI: 10.1016/j.virusres.2005.05.007] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2005] [Revised: 05/10/2005] [Accepted: 05/17/2005] [Indexed: 01/17/2023]
Abstract
A novel coronavirus (CoV) has recently been identified as the aetiological agent of severe acute respiratory syndrome (SARS). Nucleocapsid (N) proteins of the Coronaviridae family have no discernable homology, but they share a common nucleolar-cytoplasmic distribution pattern. There are three putative nuclear localization signal (NLS) motifs present in the N. To determine the role of these putative NLSs in the intracellular localization of the SARS–CoV N, we performed a confocal microscopy analysis using rabbit anti-N antisera. In this report, we show that the wild type N was distributed mainly in the cytoplasm. The N-terminal of the N, which contains the NLS1 (aa38–44), was localized to the nucleus. The C-terminus of the N, which contains both NLS2 (aa257–265) and NLS3 (aa369–390) was localized to the cytoplasm and the nucleolus. Results derived from analysis of various deletion mutations show that the region containing amino acids 226–289 is able to mediate nucleolar localization. The deletion of two hydrophobic regions that flanked the NLS3 recovered its activity and localized to the nucleus. Furthermore, deletion of leucine rich region (220-LALLLLDRLNRL) resulted in the accumulation of N to the cytoplasm and nucleolus, and when fusing this peptide to EGFP localization was cytoplasmic, suggesting that the N may act as a shuttle protein. Differences in nuclear/nucleolar localization properties of N from other members of coronavirus family suggest a unique function for N, which may play an important role in the pathogenesis of SARS.
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Affiliation(s)
- Khalid Amine Timani
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei Province 430072, PR China
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82
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Cinatl J, Michaelis M, Hoever G, Preiser W, Doerr HW. Development of antiviral therapy for severe acute respiratory syndrome. Antiviral Res 2005; 66:81-97. [PMID: 15878786 PMCID: PMC7132397 DOI: 10.1016/j.antiviral.2005.03.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Revised: 03/16/2005] [Accepted: 03/17/2005] [Indexed: 02/09/2023]
Abstract
A new disease, the severe acute respiratory distress syndrome (SARS), caused by the SARS coronavirus (SARS-CoV), emerged at the beginning of 2003 and rapidly spread throughout the world. Although the disease had disappeared in June 2003 its re-emergence cannot be excluded. The development of vaccines against SARS-CoV may take years. Therefore, the availability of effective antiviral drugs against SARS-CoV may be crucial for the control of future SARS outbreaks. In this review, experimental and clinical data about potential anti-SARS drugs is summarised and discussed. Animal model studies will be needed to help to determine which interventions warrant controlled clinical testing.
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Affiliation(s)
- Jindrich Cinatl
- Institut für Medizinische Virologie, Klinikum der Johann Wolfgang Goethe-Universität, Paul Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany.
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83
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Surjit M, Liu B, Jameel S, Chow V, Lal S. The SARS coronavirus nucleocapsid protein induces actin reorganization and apoptosis in COS-1 cells in the absence of growth factors. Biochem J 2005; 383:13-8. [PMID: 15294014 PMCID: PMC1134038 DOI: 10.1042/bj20040984] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2004] [Revised: 08/02/2004] [Accepted: 08/05/2004] [Indexed: 12/13/2022]
Abstract
In March 2003, a novel coronavirus was isolated from patients exhibiting atypical pneumonia, and was subsequently proven to be the causative agent of the disease now referred to as SARS (severe acute respiratory syndrome). The complete genome of the SARS-CoV (SARS coronavirus) has since been sequenced. The SARS-CoV nucleocapsid (SARS-CoV N) protein shares little homology with other members of the coronavirus family. In the present paper, we show that SARS-CoV N is capable of inducing apoptosis of COS-1 monkey kidney cells in the absence of growth factors by down-regulating ERK (extracellular-signal-regulated kinase), up-regulating JNK (c-Jun N-terminal kinase) and p38 MAPK (mitogen-activated protein kinase) pathways, and affecting their downstream effectors. SARS-CoV N expression also down-regulated phospho-Akt and Bcl-2 levels, and activated caspases 3 and 7. However, apoptosis was independent of the p53 and Fas signalling pathways. Furthermore, activation of the p38 MAPK pathway was found to induce actin reorganization in cells devoid of growth factors. At the cytoskeletal level, SARS-CoV N down-regulated FAK (focal adhesion kinase) activity and also down-regulated fibronectin expression. This is the first report showing the ability of the N protein of SARS-CoV to induce apoptosis and actin reorganization in mammalian cells under stressed conditions.
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Affiliation(s)
- Milan Surjit
- *Virology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Road, New Delhi 110067, India
| | - Boping Liu
- †Human Genome Laboratory, Department of Microbiology, Faculty of Medicine, National University of Singapore, Kent Ridge 117597, Singapore
| | - Shahid Jameel
- *Virology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Road, New Delhi 110067, India
| | - Vincent T. K. Chow
- †Human Genome Laboratory, Department of Microbiology, Faculty of Medicine, National University of Singapore, Kent Ridge 117597, Singapore
| | - Sunil K. Lal
- *Virology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Road, New Delhi 110067, India
- To whom correspondence should be addressed (email )
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84
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Leong W, Tan H, Ooi E, Koh D, Chow VT. Microarray and real-time RT-PCR analyses of differential human gene expression patterns induced by severe acute respiratory syndrome (SARS) coronavirus infection of Vero cells. Microbes Infect 2005; 7:248-59. [PMID: 15777647 PMCID: PMC7110627 DOI: 10.1016/j.micinf.2004.11.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Revised: 11/03/2004] [Accepted: 11/03/2004] [Indexed: 12/02/2022]
Abstract
Vero E6 African green monkey kidney cells are highly susceptible to infection with the newly emerging severe acute respiratory syndrome coronavirus (SARS-CoV), and they are permissive for rapid viral replication, with resultant cytopathic effects. We employed cDNA microarray analysis to characterize the cellular transcriptional responses of homologous human genes at 12 h post-infection. Seventy mRNA transcripts belonging to various functional classes exhibited significant alterations in gene expression. There was considerable induction of heat shock proteins that are crucial to the immune response mechanism. Modified levels of several transcripts involved in pro-inflammatory and anti-inflammatory processes exemplified the balance between opposing forces during SARS pathogenesis. Other genes displaying altered transcription included those associated with host translation, cellular metabolism, cell cycle, signal transduction, transcriptional regulation, protein trafficking, protein modulators, and cytoskeletal proteins. Alterations in the levels of several novel transcripts encoding hypothetical proteins and expressed sequence tags were also identified. In addition, transcription of apoptosis-related genes DENN and hIAP1 was upregulated in contrast to FAIM. Elevated Mx1 expression signified a strong host response to mediate antiviral resistance. Also expressed in infected cells was the C-terminal alternative splice variant of the p53 tumor suppressor gene encoding a modified truncated protein that can influence the activity of wild-type p53. We observed the interplay between various mechanisms to favor virus multiplication before full-blown apoptosis and the triggering of several pathways in host cells in an attempt to eliminate the pathogen. Microarray analysis identifies the critical host–pathogen interactions during SARS-CoV infection and provides new insights into the pathophysiology of SARS.
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Affiliation(s)
- W.F. Leong
- Human Genome Laboratory, Department of Microbiology, Faculty of Medicine, National University of Singapore, Kent Ridge, Singapore 117597, Singapore
| | - H.C. Tan
- National Environment Agency, Singapore 228231, Singapore
| | - E.E. Ooi
- National Environment Agency, Singapore 228231, Singapore
| | - D.R. Koh
- Department of Physiology, Faculty of Medicine, National University of Singapore, Kent Ridge, Singapore 117597, Singapore
| | - Vincent T.K. Chow
- Human Genome Laboratory, Department of Microbiology, Faculty of Medicine, National University of Singapore, Kent Ridge, Singapore 117597, Singapore
- Corresponding author. Tel.: +65 6874 6200; fax: +65 6776 6872.
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85
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Tan YJ, Fielding BC, Goh PY, Shen S, Tan THP, Lim SG, Hong W. Overexpression of 7a, a protein specifically encoded by the severe acute respiratory syndrome coronavirus, induces apoptosis via a caspase-dependent pathway. J Virol 2004; 78:14043-7. [PMID: 15564512 PMCID: PMC533950 DOI: 10.1128/jvi.78.24.14043-14047.2004] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Besides genes that are homologous to proteins found in other coronaviruses, the severe acute respiratory syndrome coronavirus genome also contains nine other potential open reading frames. Previously, we have characterized the expression and cellular localization of two of these "accessory" viral proteins, 3a (previously termed U274) and 7a (previously termed U122). In this study, we further examined whether they can induce apoptosis, which has been observed clinically. We showed that the overexpression of 7a, but not of 3a or the viral structural proteins, nucleocapsid, membrane, and envelope, induces apoptosis. 7a induces apoptosis via a caspase-dependent pathway and in cell lines derived from different organs, including lung, kidney, and liver.
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Affiliation(s)
- Yee-Joo Tan
- Institute of Molecular and Cell Biology, Proteos, Singapore.
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86
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Overexpression of 7a, a protein specifically encoded by the severe acute respiratory syndrome coronavirus, induces apoptosis via a caspase-dependent pathway. J Virol 2004. [PMID: 15564512 DOI: 10.1128/jvi.78.24.14043‐14047.2004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Besides genes that are homologous to proteins found in other coronaviruses, the severe acute respiratory syndrome coronavirus genome also contains nine other potential open reading frames. Previously, we have characterized the expression and cellular localization of two of these "accessory" viral proteins, 3a (previously termed U274) and 7a (previously termed U122). In this study, we further examined whether they can induce apoptosis, which has been observed clinically. We showed that the overexpression of 7a, but not of 3a or the viral structural proteins, nucleocapsid, membrane, and envelope, induces apoptosis. 7a induces apoptosis via a caspase-dependent pathway and in cell lines derived from different organs, including lung, kidney, and liver.
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