Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), the causative agent of the ongoing "porcine high fever syndrome" in China, is capable of genetic and antigenic mutations at high fre- quency. How ...Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), the causative agent of the ongoing "porcine high fever syndrome" in China, is capable of genetic and antigenic mutations at high fre- quency. How to design vaccine rationally to keep up with the ever-changing prevalent PRRSV variant is of great interest. We developed an infectious cDNA clone of an attenuated strain of Type II PRRSV, and further manipulated the infectious cDNA clone by inserting polylinker between ORF1 and ORF2, en- coding for nonstructural- or structural-protein, respectively. The cDNA was generated from the cell-attenuated virus strain, APRRS, via RT-PCR, and followed by nucleotide sequencing and molecular cloning. The full-length of the APRRS genomic RNA was determined as 15521 nucleotides in length excluding poly(A) tail, which has a 99.7% nucleotide identity with that of PRRSV Nsp strain, also a vac- cine strain. Based on the nucleotide sequencing results, the full-length cDNA clone was assembled in pBlueScript vector, under the control of T7 promoter at the immediate 5′ terminus of genome. To dis- cern the rescued viruses from that of parental virus, a Mlu I restriction site was engineered into ORF5 coding region. Upon transfection of the in vitro transcripts of both the original and Mlu I-tagged cDNAs into MA-104 cells, typical PRRSV cytopathic effects were observed. The rescued viruses from the full-length cDNA clones displayed the same virological and molecular properties. Subsequently, PCR-based mutagenesis was conducted to separate the coding regions between PRRSV nonstructural genes, ORF1, and structural proteins, ORF2-ORF7. The synthetic RNA of such mutant clone, pCSA, was infectious and the rescued virus shared similar properties with that of the parental virus. This study provided a valuable tool for development of chimeric PRRSV as vaccine candidate offering cross-protection to various genetically diversified PRRSV strains, and a platform for further develop- ment of PRRSV as a gene expression vector for recombinant vac展开更多
Enterovirus 71(EV71) is one of the main pathogens that causes hand-foot-and-mouth disease(HFMD). HFMD caused by EV71 infection is mostly self-limited; however, some infections can cause severe neurological diseases, s...Enterovirus 71(EV71) is one of the main pathogens that causes hand-foot-and-mouth disease(HFMD). HFMD caused by EV71 infection is mostly self-limited; however, some infections can cause severe neurological diseases, such as aseptic meningitis, brain stem encephalitis, and even death. There are still no effective clinical drugs used for the prevention and treatment of HFMD. Studying EV71 protein function is essential for elucidating the EV71 replication process and developing anti-EV71 drugs and vaccines. In this review, we summarized the recent progress in the studies of EV71 noncoding regions(50 UTR and 30 UTR) and all structural and nonstructural proteins, especially the key motifs involving in viral infection, replication, and immune regulation. This review will promote our understanding of EV71 virus replication and pathogenesis, and will facilitate the development of novel drugs or vaccines to treat EV71.展开更多
Middle East respiratory syndrome(MERS)is a viral respiratory disease caused by a de novo coronavirus—MERS-CoV—that is associated with high mortality.However,the mechanism by which MERS-CoV infects humans remains unc...Middle East respiratory syndrome(MERS)is a viral respiratory disease caused by a de novo coronavirus—MERS-CoV—that is associated with high mortality.However,the mechanism by which MERS-CoV infects humans remains unclear.To date,there is no effective vaccine or antibody for human immunity and treatment,other than the safety and tolerability of the fully human polyclonal Immunoglobulin G(IgG)antibody(SAB-301)as a putative therapeutic agent specific for MERS.Although rapid diagnostic and public health measures are currently being implemented,new cases of MERS-CoV infection are still being reported.Therefore,various effective measures should be taken to prevent the serious impact of similar epidemics in the future.Further investigation of the epidemiology and pathogenesis of the virus,as well as the development of effective therapeutic and prophylactic anti-MERS-CoV infections,is necessary.For this purpose,detailed information on MERS-CoV proteins is needed.In this review,we describe the major structural and nonstructural proteins of MERS-CoV and summarize different potential strategies for limiting the outbreak of MERS-CoV.The combination of computational biology and virology can accelerate the advanced design and development of effective peptide therapeutics against MERS-CoV.In summary,this review provides important information about the progress of the elimination of MERS,from prevention to treatment.展开更多
Influenza A viruses are important human pathogens causing periodic pandemic threats. Nonstructural protein 1 （NS1） protein of influenza A virus （NS1A） shields the virus against host defense. Here, we report the cr...Influenza A viruses are important human pathogens causing periodic pandemic threats. Nonstructural protein 1 （NS1） protein of influenza A virus （NS1A） shields the virus against host defense. Here, we report the crystal structure of NS1A RNA-binding domain （RBD） bound to a double-stranded RNA （dsRNA） at 1.7A. NS1A RBD forms a homodimer to recognize the major groove of A-form dsRNA in a length-independent mode by its conserved concave surface formed by dimeric anti-parallel a-helices, dsRNA is anchored by a pair of invariable arginines （Arg38） from both monomers by extensive hydrogen bonds. In accordance with the structural observation, isothermal titration calorimetry assay shows that the unique Arg38-Arg38 pair and two Arg35-Arg46 pairs are crucial for dsRNA binding, and that Ser42 and Thr49 are also important for dsRNA binding. Agrobacterium co-infiltration assay further supports that the unique Arg38 pair plays important roles in dsRNA binding in vivo.展开更多
丙型肝炎病毒(hepatitis C virus,HCV)是单股正链的RNA病毒,全长为9.6kb,包括1个大的开放阅读框(ORF)和两侧的5′,3′非编码区(UTRs).核糖体通过进入HCV5′UTR端的内部核糖体进入位点(IRES),将HCV基因组翻译成1个聚蛋白前体.前体聚蛋白...丙型肝炎病毒(hepatitis C virus,HCV)是单股正链的RNA病毒,全长为9.6kb,包括1个大的开放阅读框(ORF)和两侧的5′,3′非编码区(UTRs).核糖体通过进入HCV5′UTR端的内部核糖体进入位点(IRES),将HCV基因组翻译成1个聚蛋白前体.前体聚蛋白被宿主和病毒的蛋白酶共同切割成为若干个具有独立功能的HCV蛋白,根据功能的不同分别命名为C、E1、E2、p7、NS2、NS3、NS4A、NS4B、NS5A和NS5B,它们不但在HCV的生活史中发挥着重要的作用,也影响着宿主细胞的信号传导、凋亡及物质代谢等一系列生化过程.近年来,随着HCV体外细胞摸型的不断发展,其病毒分子生物学方面的研究取得了很大的进展.本文从基因组结构及其编码的蛋白功能等方面阐述了HCV病毒的研究进展,为致病机理的研究及抗HCV药物的开发和疫苗研制等提供理论基础.展开更多
Severe fever with thrombocytopenia syndrome(SFTS)caused by the SFTS virus(SFTSV)is an emerging disease in East Asia with a fatality rate of up to 30%.However,the viral-host interaction of SFTSV remains largely unknown...Severe fever with thrombocytopenia syndrome(SFTS)caused by the SFTS virus(SFTSV)is an emerging disease in East Asia with a fatality rate of up to 30%.However,the viral-host interaction of SFTSV remains largely unknown.The heat-shock protein 90(Hsp90)family consists of highly conserved chaperones that fold and remodel proteins and has a broad impact on the infection of many viruses.Here,we showed that Hsp90 is an important host factor involved in SFTSV infection.Hsp90 inhibitors significantly reduced SFTSV replication,viral protein expression,and the formation of inclusion bodies consisting of nonstructural proteins(NSs).Among viral proteins,NSs appeared to be the most reduced when Hsp90 inhibitors were used,and further analysis showed that their translation was affected.Co-immunoprecipitation of NSs with four isomers of Hsp90 showed that Hsp90βspecifically interacted with them.Knockdown of Hsp90βexpression also inhibited replication of SFTSV.These results suggest that Hsp90βplays a critical role during SFTSV infection and could be a potential target for the development of drugs against SFTS.展开更多
Hepatitis C virus(HCV)is a major cause of liver disease worldwide.HCV is able to evade host defense mechanisms,including both innate and acquired immune responses,to establish persistent infection,which results in a b...Hepatitis C virus(HCV)is a major cause of liver disease worldwide.HCV is able to evade host defense mechanisms,including both innate and acquired immune responses,to establish persistent infection,which results in a broad spectrum of pathogenicity,such as lipid and glucose metabolism disorders and hepatocellular carcinoma development.The HCV genome is characterized by a high degree of genetic diversity,which can be associated with viral sensitivity or resistance(reflected by different virological responses)to interferon(IFN)-based therapy.In this regard,it is of importance to note that polymorphisms in certain HCV genomic regions have shown a close correlation with treatment outcome.In particular,among the HCV proteins,the core and nonstructural proteins(NS)5A have been extensively studied for their correlation with responses to IFN-based treatment.This review aims to cover updated information on the impact of major HCV genetic factors,including HCV genotype,mutations in amino acids 70 and91 of the core protein and sequence heterogeneity in the IFN sensitivity-determining region and IFN/ribavirin resistance-determining region of NS5A,on virological responses to IFN-based therapy.展开更多
AIM： To investigate effects of iron on oxidative stress, heme oxygenase-1 （HMOX1） and hepatitis C viral （HCV） expression in human hepatoma ceils stably expressing HCV proteins. METHODS： Effects of iron on oxidat...AIM： To investigate effects of iron on oxidative stress, heme oxygenase-1 （HMOX1） and hepatitis C viral （HCV） expression in human hepatoma ceils stably expressing HCV proteins. METHODS： Effects of iron on oxidative stress, HMOX1, and HCV expression were assessed in CON1 cells. Measurements included mRNA by quantitative reverse transcription-polymerase chain reaction, and protein levels by Western blots. RESULTS： Iron, in the form of ferric nitrilotriacetate,increased oxidative stress and upegulated HMOX1 gene expression. Iron did not affect mRNA or protein levels of Bach1, a repressor of HMOXl. Silencing the up-regulation of HMOXl nuclear factor-erythroid 2-related factor 2 （Nrf2） by Nrf2-siRNA decreased FeNTA-mediated up-regulation of HMOXl mRNA levels. These iron effects were completely blocked by deferoxamine （DFO）. Iron also significantly decreased levels of HCV core mRNA and protein by 80%-90%, nonstructural 5A mRNA by 90% and protein by about 50% in the Con1 full length HCV replicon cells, whereas DFO increased them. CONCLUSION： Excess iron up-regulates HMOXl and down-regulates HCV gene expression in hepatoma cells. This probably mitigates liver injury caused by combined iron overload and HCV infection.展开更多
Viral nonstructural proteins in both enveloped and non-enveloped viruses play important roles in viral replication. Protein NS38 of Grass carp reovirus (GCRV), has been deduced to be a non-structural protein, and, con...Viral nonstructural proteins in both enveloped and non-enveloped viruses play important roles in viral replication. Protein NS38 of Grass carp reovirus (GCRV), has been deduced to be a non-structural protein, and, consistent with other reoviruses, is considered to cooperate with the NS80 protein in viral particle assembly. To investigate the molecular basis of the role of NS38, a complete protein was expressed in E.coli for the first time. It was found that there is a better expression of NS38 induced with IPTG at 28 ℃ rather than 37 ℃. In addition, the antiserum of NS38 prepared with purified fusion protein and injected into rabbit could be used for detecting NS38 protein expression in GCRV infected cell lysate, while there is not any reaction crossed with purified virus particle, confirming NS38 is not a component of the viral structural protein. The result reported in this study will provide evidence for further viral protein-protein and protein-RNA interaction in dsRNA viruses replication.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No. 30530580)the National Basic Research Project of China (Grant No. 2005CB523200)
文摘Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), the causative agent of the ongoing "porcine high fever syndrome" in China, is capable of genetic and antigenic mutations at high fre- quency. How to design vaccine rationally to keep up with the ever-changing prevalent PRRSV variant is of great interest. We developed an infectious cDNA clone of an attenuated strain of Type II PRRSV, and further manipulated the infectious cDNA clone by inserting polylinker between ORF1 and ORF2, en- coding for nonstructural- or structural-protein, respectively. The cDNA was generated from the cell-attenuated virus strain, APRRS, via RT-PCR, and followed by nucleotide sequencing and molecular cloning. The full-length of the APRRS genomic RNA was determined as 15521 nucleotides in length excluding poly(A) tail, which has a 99.7% nucleotide identity with that of PRRSV Nsp strain, also a vac- cine strain. Based on the nucleotide sequencing results, the full-length cDNA clone was assembled in pBlueScript vector, under the control of T7 promoter at the immediate 5′ terminus of genome. To dis- cern the rescued viruses from that of parental virus, a Mlu I restriction site was engineered into ORF5 coding region. Upon transfection of the in vitro transcripts of both the original and Mlu I-tagged cDNAs into MA-104 cells, typical PRRSV cytopathic effects were observed. The rescued viruses from the full-length cDNA clones displayed the same virological and molecular properties. Subsequently, PCR-based mutagenesis was conducted to separate the coding regions between PRRSV nonstructural genes, ORF1, and structural proteins, ORF2-ORF7. The synthetic RNA of such mutant clone, pCSA, was infectious and the rescued virus shared similar properties with that of the parental virus. This study provided a valuable tool for development of chimeric PRRSV as vaccine candidate offering cross-protection to various genetically diversified PRRSV strains, and a platform for further develop- ment of PRRSV as a gene expression vector for recombinant vac
基金supported by the National Natural Science Foundation of China (Grant 81503118)CAMS Initiative for Innovative Medicine (CAMS-I2 M-1-010)The National Science and Technology Major Project of the Ministry of Science and Technology of China (2018ZX09711003-005-004)
文摘Enterovirus 71(EV71) is one of the main pathogens that causes hand-foot-and-mouth disease(HFMD). HFMD caused by EV71 infection is mostly self-limited; however, some infections can cause severe neurological diseases, such as aseptic meningitis, brain stem encephalitis, and even death. There are still no effective clinical drugs used for the prevention and treatment of HFMD. Studying EV71 protein function is essential for elucidating the EV71 replication process and developing anti-EV71 drugs and vaccines. In this review, we summarized the recent progress in the studies of EV71 noncoding regions(50 UTR and 30 UTR) and all structural and nonstructural proteins, especially the key motifs involving in viral infection, replication, and immune regulation. This review will promote our understanding of EV71 virus replication and pathogenesis, and will facilitate the development of novel drugs or vaccines to treat EV71.
文摘Middle East respiratory syndrome(MERS)is a viral respiratory disease caused by a de novo coronavirus—MERS-CoV—that is associated with high mortality.However,the mechanism by which MERS-CoV infects humans remains unclear.To date,there is no effective vaccine or antibody for human immunity and treatment,other than the safety and tolerability of the fully human polyclonal Immunoglobulin G(IgG)antibody(SAB-301)as a putative therapeutic agent specific for MERS.Although rapid diagnostic and public health measures are currently being implemented,new cases of MERS-CoV infection are still being reported.Therefore,various effective measures should be taken to prevent the serious impact of similar epidemics in the future.Further investigation of the epidemiology and pathogenesis of the virus,as well as the development of effective therapeutic and prophylactic anti-MERS-CoV infections,is necessary.For this purpose,detailed information on MERS-CoV proteins is needed.In this review,we describe the major structural and nonstructural proteins of MERS-CoV and summarize different potential strategies for limiting the outbreak of MERS-CoV.The combination of computational biology and virology can accelerate the advanced design and development of effective peptide therapeutics against MERS-CoV.In summary,this review provides important information about the progress of the elimination of MERS,from prevention to treatment.
文摘Influenza A viruses are important human pathogens causing periodic pandemic threats. Nonstructural protein 1 （NS1） protein of influenza A virus （NS1A） shields the virus against host defense. Here, we report the crystal structure of NS1A RNA-binding domain （RBD） bound to a double-stranded RNA （dsRNA） at 1.7A. NS1A RBD forms a homodimer to recognize the major groove of A-form dsRNA in a length-independent mode by its conserved concave surface formed by dimeric anti-parallel a-helices, dsRNA is anchored by a pair of invariable arginines （Arg38） from both monomers by extensive hydrogen bonds. In accordance with the structural observation, isothermal titration calorimetry assay shows that the unique Arg38-Arg38 pair and two Arg35-Arg46 pairs are crucial for dsRNA binding, and that Ser42 and Thr49 are also important for dsRNA binding. Agrobacterium co-infiltration assay further supports that the unique Arg38 pair plays important roles in dsRNA binding in vivo.
文摘丙型肝炎病毒(hepatitis C virus,HCV)是单股正链的RNA病毒,全长为9.6kb,包括1个大的开放阅读框(ORF)和两侧的5′,3′非编码区(UTRs).核糖体通过进入HCV5′UTR端的内部核糖体进入位点(IRES),将HCV基因组翻译成1个聚蛋白前体.前体聚蛋白被宿主和病毒的蛋白酶共同切割成为若干个具有独立功能的HCV蛋白,根据功能的不同分别命名为C、E1、E2、p7、NS2、NS3、NS4A、NS4B、NS5A和NS5B,它们不但在HCV的生活史中发挥着重要的作用,也影响着宿主细胞的信号传导、凋亡及物质代谢等一系列生化过程.近年来,随着HCV体外细胞摸型的不断发展,其病毒分子生物学方面的研究取得了很大的进展.本文从基因组结构及其编码的蛋白功能等方面阐述了HCV病毒的研究进展,为致病机理的研究及抗HCV药物的开发和疫苗研制等提供理论基础.
基金supported by grants from the National Natural Science Foundation of China(31900146)the key Biosafety Science and Technology Program of Hubei Jiangxia Laboratory(JXBS001)+1 种基金the Hubei Natural Science Foundation for Distinguished Young Scholars(2021CFA050)the Creative Research Group Program of Natural Science Foundation of Hubei Province(2022CFA021).
文摘Severe fever with thrombocytopenia syndrome(SFTS)caused by the SFTS virus(SFTSV)is an emerging disease in East Asia with a fatality rate of up to 30%.However,the viral-host interaction of SFTSV remains largely unknown.The heat-shock protein 90(Hsp90)family consists of highly conserved chaperones that fold and remodel proteins and has a broad impact on the infection of many viruses.Here,we showed that Hsp90 is an important host factor involved in SFTSV infection.Hsp90 inhibitors significantly reduced SFTSV replication,viral protein expression,and the formation of inclusion bodies consisting of nonstructural proteins(NSs).Among viral proteins,NSs appeared to be the most reduced when Hsp90 inhibitors were used,and further analysis showed that their translation was affected.Co-immunoprecipitation of NSs with four isomers of Hsp90 showed that Hsp90βspecifically interacted with them.Knockdown of Hsp90βexpression also inhibited replication of SFTSV.These results suggest that Hsp90βplays a critical role during SFTSV infection and could be a potential target for the development of drugs against SFTS.
基金Supported by A Health and Labour Sciences Research Grant from the Ministry of Health,Labour and Welfare,Japan,a SATREPS Grant from Japan Science and Technology Agency and Japan International Cooperation Agencythe Japan Initiative for Global Research Network on Infectious Diseases(J-GRID)program from the Ministry of Education,Culture,Sports,Science and Technology,Japan
文摘Hepatitis C virus(HCV)is a major cause of liver disease worldwide.HCV is able to evade host defense mechanisms,including both innate and acquired immune responses,to establish persistent infection,which results in a broad spectrum of pathogenicity,such as lipid and glucose metabolism disorders and hepatocellular carcinoma development.The HCV genome is characterized by a high degree of genetic diversity,which can be associated with viral sensitivity or resistance(reflected by different virological responses)to interferon(IFN)-based therapy.In this regard,it is of importance to note that polymorphisms in certain HCV genomic regions have shown a close correlation with treatment outcome.In particular,among the HCV proteins,the core and nonstructural proteins(NS)5A have been extensively studied for their correlation with responses to IFN-based treatment.This review aims to cover updated information on the impact of major HCV genetic factors,including HCV genotype,mutations in amino acids 70 and91 of the core protein and sequence heterogeneity in the IFN sensitivity-determining region and IFN/ribavirin resistance-determining region of NS5A,on virological responses to IFN-based therapy.
基金Supported by Grant(DK RO1 38825) and contracts(DK NO129236 and UO1 DK 06193)from the National Institutes of Health(NIDDK)
文摘AIM： To investigate effects of iron on oxidative stress, heme oxygenase-1 （HMOX1） and hepatitis C viral （HCV） expression in human hepatoma ceils stably expressing HCV proteins. METHODS： Effects of iron on oxidative stress, HMOX1, and HCV expression were assessed in CON1 cells. Measurements included mRNA by quantitative reverse transcription-polymerase chain reaction, and protein levels by Western blots. RESULTS： Iron, in the form of ferric nitrilotriacetate,increased oxidative stress and upegulated HMOX1 gene expression. Iron did not affect mRNA or protein levels of Bach1, a repressor of HMOXl. Silencing the up-regulation of HMOXl nuclear factor-erythroid 2-related factor 2 （Nrf2） by Nrf2-siRNA decreased FeNTA-mediated up-regulation of HMOXl mRNA levels. These iron effects were completely blocked by deferoxamine （DFO）. Iron also significantly decreased levels of HCV core mRNA and protein by 80%-90%, nonstructural 5A mRNA by 90% and protein by about 50% in the Con1 full length HCV replicon cells, whereas DFO increased them. CONCLUSION： Excess iron up-regulates HMOXl and down-regulates HCV gene expression in hepatoma cells. This probably mitigates liver injury caused by combined iron overload and HCV infection.
基金National Basic Research Program (973) of China ( 2009CB118701)National Natural Scientific Foundation of China (30871940, 30671615)
文摘Viral nonstructural proteins in both enveloped and non-enveloped viruses play important roles in viral replication. Protein NS38 of Grass carp reovirus (GCRV), has been deduced to be a non-structural protein, and, consistent with other reoviruses, is considered to cooperate with the NS80 protein in viral particle assembly. To investigate the molecular basis of the role of NS38, a complete protein was expressed in E.coli for the first time. It was found that there is a better expression of NS38 induced with IPTG at 28 ℃ rather than 37 ℃. In addition, the antiserum of NS38 prepared with purified fusion protein and injected into rabbit could be used for detecting NS38 protein expression in GCRV infected cell lysate, while there is not any reaction crossed with purified virus particle, confirming NS38 is not a component of the viral structural protein. The result reported in this study will provide evidence for further viral protein-protein and protein-RNA interaction in dsRNA viruses replication.
