Subgenomic replicons of hepatitis C virus （HCV） have been widely used for studying HCV replication.Here,we report a new subgenomic replicon based on a strain isolated from a chronically infected patient.The coding s...Subgenomic replicons of hepatitis C virus （HCV） have been widely used for studying HCV replication.Here,we report a new subgenomic replicon based on a strain isolated from a chronically infected patient.The coding sequence of HCV was recovered from a Chinese chronic hepatitis C patient displaying high serum HCV copy numbers.A consensus sequence designated as CCH strain was constructed based on the sequences of five clones and this was classified by sequence alignment as belonging to genotype 2a.The subgenomic replicon of CCH was replication-deficient in cell culture,due to dysfunctions in NS3 and NS5B.Various JFH1/CCH chimeric replicons were constructed,and specific mutations were introduced.The introduction of mutations could partially restore the replication of chimeric replicons.A replication-competent chimeric construct was finally obtained by the introduction of NS3 from JFH1 into the backbone of the CCH strain.展开更多
We developed a Gaussia luciferase (Gluc) reporter replicon of West Nile virus (WNV) and used it to quantify viral translation and RNA replication. The advantage of the Gluc replicon is that Gaussia luciferase is secre...We developed a Gaussia luciferase (Gluc) reporter replicon of West Nile virus (WNV) and used it to quantify viral translation and RNA replication. The advantage of the Gluc replicon is that Gaussia luciferase is secreted into the culture medium from cells transfected with Gluc replicon RNA, and the medium can be assayed directly for luciferase activity. Using a known Flavivirus inhibitor (NITD008), we demonstrated that the Gluc-WNV replicon could be used for antiviral screening. The Gluc-WNV-Rep will be useful for research in antiviral drug development programs, as well as for studying viral replication and pathogenesis of WNV.展开更多
AIM: To construct a tricistronic hepatitis C virus (HCV) replicon with double internal ribosome entry sites (IRESes) of only 22 nucleotides for each, substituting the encephalomyocarditis virus (EMCV) IRESes, which ar...AIM: To construct a tricistronic hepatitis C virus (HCV) replicon with double internal ribosome entry sites (IRESes) of only 22 nucleotides for each, substituting the encephalomyocarditis virus (EMCV) IRESes, which are most often used as the translation initiation element to form HCV replicons.展开更多
A high throughput screen of the Pfizer compound collection was carried out using a hepatitis C virus (HCV) genotype 1b subgenomic replicon cell line. Those confirmed hits that demonstrated broad spectrum activity with...A high throughput screen of the Pfizer compound collection was carried out using a hepatitis C virus (HCV) genotype 1b subgenomic replicon cell line. Those confirmed hits that demonstrated broad spectrum activity without overt cytotoxicity were further evaluated, leading to the identification of a series of pyrrolopyridines with excellent antiviral activity in a fully infectious HCV cell-based assay and pharmacokinetic properties.展开更多
Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has caused a devastating pandemic worldwide.Vaccines and antiviral drugs are the most promising candidates for combating this global epidemic,and scientists a...Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has caused a devastating pandemic worldwide.Vaccines and antiviral drugs are the most promising candidates for combating this global epidemic,and scientists all over the world have made great efforts to this end.However,manipulation of the SARS-CoV-2 should be performed in the biosafety level3 laboratory.This makes experiments complicated and time-consuming.Therefore,a safer system for working with this virus is urgently needed.Here,we report the construction of plasmid-based,non-infectious SARS-CoV-2 replicons with turbo-green fluorescent protein and/or firefly luciferase reporters by reverse genetics using transformation-associated recombination cloning in Saccharomyces cerevisiae.Replication of these replicons was achieved simply by direct transfection of cells with the replicon plasmids as evident by the expression of reporter genes.Using SARS-CoV-2 replicons,the inhibitory effects of E64-D and remdesivir on SARS-CoV-2 replication were confirmed,and the halfmaximal effective concentration(EC50)value of remdesivir and E64-D was estimated by different quantification methods respectively,indicating that these SARS-CoV-2 replicons are useful tools for antiviral drug evaluation.展开更多
SARS-CoV-2 causes the pandemic of COVID-19 and no effective drugs for this disease are available thus far.Due to the high infectivity and pathogenicity of this virus,all studies on the live virus are strictly confined...SARS-CoV-2 causes the pandemic of COVID-19 and no effective drugs for this disease are available thus far.Due to the high infectivity and pathogenicity of this virus,all studies on the live virus are strictly confined in the biosafety level 3(BSL3)laboratory but this would hinder the basic research and antiviral drug development of SARS-CoV-2 because the BSL3 facility is not commonly available and the work in the containment is costly and laborious.In this study,we constructed a reverse genetics system of SARS-CoV-2 by assembling the viral cDNA in a bacterial artificial chromosome(BAC)vector with deletion of the spike(S)gene.Transfection of the cDNA into cells results in the production of an RNA replicon that keeps the capability of genome or subgenome replication but is deficient in virion assembly and infection due to the absence of S protein.Therefore,such a replicon system is not infectious and can be used in ordinary biological laboratories.We confirmed the efficient replication of the replicon by demonstrating the expression of the subgenomic RNAs which have similar profiles to the wild-type virus.By mutational analysis of nsp12 and nsp14,we showed that the RNA polymerase,exonuclease,and cap N7 methyltransferase play essential roles in genome replication and sgRNA production.We also created a SARS-CoV-2 replicon carrying a luciferase reporter gene and this system was validated by the inhibition assays with known anti-SARS-CoV-2 inhibitors.Thus,such a one-plasmid system is biosafe and convenient to use,which will benefit both fundamental research and development of antiviral drugs.展开更多
The 2016 Lasker-DeBakey Clinical Medical Research Award was given to three scientists working on different stages of the translational sciences on bringing a high efficacious therapy against hepatitis C virus （HCV） ...The 2016 Lasker-DeBakey Clinical Medical Research Award was given to three scientists working on different stages of the translational sciences on bringing a high efficacious therapy against hepatitis C virus （HCV） infection to a reality. An effective treatment of HCV chronic infection was developed, by a team led by Michael Sofia, using a prodrug approach and the drug PSI-7977 or Sofosbuvir was approved in 2013 less than 28 years after the initial discovery of HCV.展开更多
Several variants of concern(VOCs)have emerged since the WIV04 strain of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)was first isolated in January 2020.Due to mutations in the spike(S)protein,these VOCs ...Several variants of concern(VOCs)have emerged since the WIV04 strain of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)was first isolated in January 2020.Due to mutations in the spike(S)protein,these VOCs have evolved to enhance viral infectivity and immune evasion.However,whether mutations of the other viral proteins lead to altered viral propagation and drug resistance remains obscure.The replicon is a noninfectious viral surrogate capable of recapitulating certain steps of the viral life cycle.Although several SARS-CoV-2 replicons have been developed,none of them were derived from emerging VOCs and could only recapitulate viral genome replication and subgenomic RNA(sgRNA)transcription.In this study,SARS-CoV-2 replicons derived from the WIV04 strain and two VOCs(the Beta and Delta variants)were prepared by removing the S gene from their genomes,while other structural genes remained untouched.These replicons not only recapitulate viral genome replication and sgRNA transcription but also support the assembly and release of viral-like particles,as manifested by electron microscopic assays.Thus,the S-deletion replicon could recapitulate virtually all the post-entry steps of the viral life cycle and provides a versatile tool for measuring viral intracellular propagation and screening novel antiviral drugs,including inhibitors of virion assembly and release.Through the quantification of replicon RNA released into the supernatant,we demonstrate that viral intracellular propagation and drug response to remdesivir have not yet substantially changed during the evolution of SARS-CoV-2 from the WIV04 strain to the Beta and Delta VOCs.展开更多
ADENO-ASSOCIATED virus (AAV) was a human parvovirus considered as a gene delivery vehiclefor human gene therapy. Recombinant AAV vector (rAAV) could mediate the foreign DNAintegration into chromosome and establish a s...ADENO-ASSOCIATED virus (AAV) was a human parvovirus considered as a gene delivery vehiclefor human gene therapy. Recombinant AAV vector (rAAV) could mediate the foreign DNAintegration into chromosome and establish a stable expression in the infected cells. As a viraltransduction vector, rAAV was superior to the traditional retrovirus vector for its high safety.no pathogenicity, and capacity of infecting postmitosis cells. The current strategy for produc-展开更多
Middle East respiratory syndrome coronavirus(MERS-CoV)is the causative agent of a severe respiratory disease with a high mortality of~35%.The lack of approved treatments for MERS-CoV infection underscores the need for...Middle East respiratory syndrome coronavirus(MERS-CoV)is the causative agent of a severe respiratory disease with a high mortality of~35%.The lack of approved treatments for MERS-CoV infection underscores the need for a user-friendly system for rapid drug screening.In this study,we constructed a MERS-CoV replicon containing the Renilla luciferase(Rluc)reporter gene and a stable luciferase replicon-carrying cell line.Using this cell line,we showed that MERS-CoV replication was inhibited by combined application of lopinavir and ritonavir,indicating that this cell line can be used to screen inhibitors of MERS-CoV replication.Importantly,the MERS-replicon cell line can be used for high-throughput screening of antiviral drugs without the need for live virus handling,providing an effective and safe tool for the discovery of antiviral drugs against MERS-CoV.展开更多
基金supported by grants from the National Basic Research Priorities Program of China(2013CB911101)the National Nature Science Foundation of China(Grant 31200315)
文摘Subgenomic replicons of hepatitis C virus （HCV） have been widely used for studying HCV replication.Here,we report a new subgenomic replicon based on a strain isolated from a chronically infected patient.The coding sequence of HCV was recovered from a Chinese chronic hepatitis C patient displaying high serum HCV copy numbers.A consensus sequence designated as CCH strain was constructed based on the sequences of five clones and this was classified by sequence alignment as belonging to genotype 2a.The subgenomic replicon of CCH was replication-deficient in cell culture,due to dysfunctions in NS3 and NS5B.Various JFH1/CCH chimeric replicons were constructed,and specific mutations were introduced.The introduction of mutations could partially restore the replication of chimeric replicons.A replication-competent chimeric construct was finally obtained by the introduction of NS3 from JFH1 into the backbone of the CCH strain.
基金supported by the National Natural Science Foundation of China (grant No. 31170158 and 31000090)the '100 Talents Project' of Chinese Academy of Sciences, China (grant No. Y002171YC1)
文摘We developed a Gaussia luciferase (Gluc) reporter replicon of West Nile virus (WNV) and used it to quantify viral translation and RNA replication. The advantage of the Gluc replicon is that Gaussia luciferase is secreted into the culture medium from cells transfected with Gluc replicon RNA, and the medium can be assayed directly for luciferase activity. Using a known Flavivirus inhibitor (NITD008), we demonstrated that the Gluc-WNV replicon could be used for antiviral screening. The Gluc-WNV-Rep will be useful for research in antiviral drug development programs, as well as for studying viral replication and pathogenesis of WNV.
基金Supported by Grants from the Study on Prevention and Control of Viral Hepatitis in the Key Program for Science and Technology Development of Hebei Province,No.10276102D
文摘AIM: To construct a tricistronic hepatitis C virus (HCV) replicon with double internal ribosome entry sites (IRESes) of only 22 nucleotides for each, substituting the encephalomyocarditis virus (EMCV) IRESes, which are most often used as the translation initiation element to form HCV replicons.
文摘A high throughput screen of the Pfizer compound collection was carried out using a hepatitis C virus (HCV) genotype 1b subgenomic replicon cell line. Those confirmed hits that demonstrated broad spectrum activity without overt cytotoxicity were further evaluated, leading to the identification of a series of pyrrolopyridines with excellent antiviral activity in a fully infectious HCV cell-based assay and pharmacokinetic properties.
基金supported by the CAMS Innovation Fund for Medical Science(CIFMS 2016-I2M-1-014)the National Key Plan for Scientific Research and Development of China(2016YFD0500300)+1 种基金National Key R&D Program of China(2020YFA0707600)Beijing Municipal Science and Technology Project(Z201100001020005)。
文摘Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has caused a devastating pandemic worldwide.Vaccines and antiviral drugs are the most promising candidates for combating this global epidemic,and scientists all over the world have made great efforts to this end.However,manipulation of the SARS-CoV-2 should be performed in the biosafety level3 laboratory.This makes experiments complicated and time-consuming.Therefore,a safer system for working with this virus is urgently needed.Here,we report the construction of plasmid-based,non-infectious SARS-CoV-2 replicons with turbo-green fluorescent protein and/or firefly luciferase reporters by reverse genetics using transformation-associated recombination cloning in Saccharomyces cerevisiae.Replication of these replicons was achieved simply by direct transfection of cells with the replicon plasmids as evident by the expression of reporter genes.Using SARS-CoV-2 replicons,the inhibitory effects of E64-D and remdesivir on SARS-CoV-2 replication were confirmed,and the halfmaximal effective concentration(EC50)value of remdesivir and E64-D was estimated by different quantification methods respectively,indicating that these SARS-CoV-2 replicons are useful tools for antiviral drug evaluation.
基金supported by Grants(the National Natural Science Foundation of China#32041002,#31971161,#31900546 and#81620108020)the Guangdong Science and Technology Department(#2019A1515011332)+1 种基金the Shenzhen Science and Technology Innovation Program(JSGG20200225150431472,JCYJ20190807160615255,JCYJ20190807153203560,and KQTD20180411143323605)supported by the Guangdong Zhujiang Leading Talents Programme and the National Tenthousand Talents Program。
文摘SARS-CoV-2 causes the pandemic of COVID-19 and no effective drugs for this disease are available thus far.Due to the high infectivity and pathogenicity of this virus,all studies on the live virus are strictly confined in the biosafety level 3(BSL3)laboratory but this would hinder the basic research and antiviral drug development of SARS-CoV-2 because the BSL3 facility is not commonly available and the work in the containment is costly and laborious.In this study,we constructed a reverse genetics system of SARS-CoV-2 by assembling the viral cDNA in a bacterial artificial chromosome(BAC)vector with deletion of the spike(S)gene.Transfection of the cDNA into cells results in the production of an RNA replicon that keeps the capability of genome or subgenome replication but is deficient in virion assembly and infection due to the absence of S protein.Therefore,such a replicon system is not infectious and can be used in ordinary biological laboratories.We confirmed the efficient replication of the replicon by demonstrating the expression of the subgenomic RNAs which have similar profiles to the wild-type virus.By mutational analysis of nsp12 and nsp14,we showed that the RNA polymerase,exonuclease,and cap N7 methyltransferase play essential roles in genome replication and sgRNA production.We also created a SARS-CoV-2 replicon carrying a luciferase reporter gene and this system was validated by the inhibition assays with known anti-SARS-CoV-2 inhibitors.Thus,such a one-plasmid system is biosafe and convenient to use,which will benefit both fundamental research and development of antiviral drugs.
文摘The 2016 Lasker-DeBakey Clinical Medical Research Award was given to three scientists working on different stages of the translational sciences on bringing a high efficacious therapy against hepatitis C virus （HCV） infection to a reality. An effective treatment of HCV chronic infection was developed, by a team led by Michael Sofia, using a prodrug approach and the drug PSI-7977 or Sofosbuvir was approved in 2013 less than 28 years after the initial discovery of HCV.
基金supported by grants from the National Key Research and Development Project of China (2020YFC0845900)the China Postdoctoral Science Foundation (2020T130021ZX,2021M693198)
文摘Several variants of concern(VOCs)have emerged since the WIV04 strain of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)was first isolated in January 2020.Due to mutations in the spike(S)protein,these VOCs have evolved to enhance viral infectivity and immune evasion.However,whether mutations of the other viral proteins lead to altered viral propagation and drug resistance remains obscure.The replicon is a noninfectious viral surrogate capable of recapitulating certain steps of the viral life cycle.Although several SARS-CoV-2 replicons have been developed,none of them were derived from emerging VOCs and could only recapitulate viral genome replication and subgenomic RNA(sgRNA)transcription.In this study,SARS-CoV-2 replicons derived from the WIV04 strain and two VOCs(the Beta and Delta variants)were prepared by removing the S gene from their genomes,while other structural genes remained untouched.These replicons not only recapitulate viral genome replication and sgRNA transcription but also support the assembly and release of viral-like particles,as manifested by electron microscopic assays.Thus,the S-deletion replicon could recapitulate virtually all the post-entry steps of the viral life cycle and provides a versatile tool for measuring viral intracellular propagation and screening novel antiviral drugs,including inhibitors of virion assembly and release.Through the quantification of replicon RNA released into the supernatant,we demonstrate that viral intracellular propagation and drug response to remdesivir have not yet substantially changed during the evolution of SARS-CoV-2 from the WIV04 strain to the Beta and Delta VOCs.
文摘ADENO-ASSOCIATED virus (AAV) was a human parvovirus considered as a gene delivery vehiclefor human gene therapy. Recombinant AAV vector (rAAV) could mediate the foreign DNAintegration into chromosome and establish a stable expression in the infected cells. As a viraltransduction vector, rAAV was superior to the traditional retrovirus vector for its high safety.no pathogenicity, and capacity of infecting postmitosis cells. The current strategy for produc-
基金This study was supported by the strategic priority research program of the Chinese academy of sciences(XDB29010101).
文摘Middle East respiratory syndrome coronavirus(MERS-CoV)is the causative agent of a severe respiratory disease with a high mortality of~35%.The lack of approved treatments for MERS-CoV infection underscores the need for a user-friendly system for rapid drug screening.In this study,we constructed a MERS-CoV replicon containing the Renilla luciferase(Rluc)reporter gene and a stable luciferase replicon-carrying cell line.Using this cell line,we showed that MERS-CoV replication was inhibited by combined application of lopinavir and ritonavir,indicating that this cell line can be used to screen inhibitors of MERS-CoV replication.Importantly,the MERS-replicon cell line can be used for high-throughput screening of antiviral drugs without the need for live virus handling,providing an effective and safe tool for the discovery of antiviral drugs against MERS-CoV.
