Ectromelia virus(ECTV),a member of the Orthopoxvirus genus,serves as both a causative agent of mousepox and a pivotal surrogate model for studying highly pathogenic orthopoxviruses.Although genomic data on ECTV remain...Ectromelia virus(ECTV),a member of the Orthopoxvirus genus,serves as both a causative agent of mousepox and a pivotal surrogate model for studying highly pathogenic orthopoxviruses.Although genomic data on ECTV remains limited,we report the isolation and characterization of a novel strain,ECTV-C-Tan-GD01,obtained from rodents in Guangdong Province,China.Nanopore sequencing yielded a complete genome(199 annotated genes,including one gene truncated at the C-terminus)with inverted terminal repeats(ITRs)harboring a conserved hairpin structure.Notably,a frameshift-inducing“G”deletion in the EV159 gene resulted in the truncation of a semaphorin-like protein.In vitro assays demonstrated cell-associated viral replication kinetics,with maximum titers achieved earlier in Vero/HeLa cells(72 h)than in BHK-21/CEF cells(84 h).Murine challenge experiments revealed extreme virulence(LD50<1 plaque-forming unit(PFU)via intranasal/footpad routes)and hepatosplenic tropism.Furthermore,ECTV-C-Tan-GD01 exhibited utility in evaluating orthopoxvirus countermeasures:a single dose of vaccinia virus Tiantan(VTT)or non-replicating vaccinia virus Tiantan(NTV)conferred cross-protection,while tecovirimat(ST-246),cidofovir(CDV),and brincidofovir(initially CMX001)significantly reduced viral loads and pathology.This study establishes ECTV-C-Tan-GD01 as a dual-purpose resource for probing orthopoxvirus evolution and advancing therapeutic development.展开更多
Viral infectious clones(ICs)serve as robust platforms for studying viral biology and screening antiviral agents using reverse genetics.However,the molecular profiles and complex limitations of human coronaviruses(HCoV...Viral infectious clones(ICs)serve as robust platforms for studying viral biology and screening antiviral agents using reverse genetics.However,the molecular profiles and complex limitations of human coronaviruses(HCoVs)pose a challenge to ICs development.In this study,we report a novel platform to develop the ICs for HCoV-OC43-VR1558 using a one-step assembly method in yeast by transformation-associated recombination(TAR)technology.Recombinant HCoV-OC43-VR1558,named as rOC43(1558)-WT,was rapidly generated by TAR.In addition,recombinant HCoV-OC43-VR1558-expressing reporter genes,named as rOC43(1558)-ns2FusionRluc,was also generated based on TAR by inserting the ns2 region of the IC with Renilla luciferase(Rluc).We further characterized their replication through virus titration using 50%tissue culture infective dose(TCID50)and indirect immunofluorescence assay(IFA),luciferase reporter assay,and western blotting(WB)assay.The genetic stability of the recombinant HCoV-OC43 was assessed through viral genome sequencing following passaging in BHK-21 cells.These reporter viruses were validated as screening tools for inhibitorsin vitro by evaluating the antiviral activities of remdesivir and chloroquine.The phenotypes of HCoV-OC43-VR1558 and HCoV-OC43-VR759 were comparedin vitro andin vivo.The TAR-based one-step assembly of IC was successfully applied,facilitating the rapid generation of recombinant HCoV-OC43 and providing a useful platform for the investigation of biological mechanisms,development of vaccines and diagnostic tests,and screening inhibitors of HCoVs.展开更多
基金supported by the Natural Science Foundation of Beijing(7254390)the Youth Science Foundation of Chinese Center for Disease Control and Prevention(2024A103)to W.C.C,the National Key ResearchDevelopment Program of China(2022YFC2304100,2023YFD1800405).
文摘Ectromelia virus(ECTV),a member of the Orthopoxvirus genus,serves as both a causative agent of mousepox and a pivotal surrogate model for studying highly pathogenic orthopoxviruses.Although genomic data on ECTV remains limited,we report the isolation and characterization of a novel strain,ECTV-C-Tan-GD01,obtained from rodents in Guangdong Province,China.Nanopore sequencing yielded a complete genome(199 annotated genes,including one gene truncated at the C-terminus)with inverted terminal repeats(ITRs)harboring a conserved hairpin structure.Notably,a frameshift-inducing“G”deletion in the EV159 gene resulted in the truncation of a semaphorin-like protein.In vitro assays demonstrated cell-associated viral replication kinetics,with maximum titers achieved earlier in Vero/HeLa cells(72 h)than in BHK-21/CEF cells(84 h).Murine challenge experiments revealed extreme virulence(LD50<1 plaque-forming unit(PFU)via intranasal/footpad routes)and hepatosplenic tropism.Furthermore,ECTV-C-Tan-GD01 exhibited utility in evaluating orthopoxvirus countermeasures:a single dose of vaccinia virus Tiantan(VTT)or non-replicating vaccinia virus Tiantan(NTV)conferred cross-protection,while tecovirimat(ST-246),cidofovir(CDV),and brincidofovir(initially CMX001)significantly reduced viral loads and pathology.This study establishes ECTV-C-Tan-GD01 as a dual-purpose resource for probing orthopoxvirus evolution and advancing therapeutic development.
基金supported by the National Key Research and Development Program of China(2022YFC2304100 and 2021YFA1201003).
文摘Viral infectious clones(ICs)serve as robust platforms for studying viral biology and screening antiviral agents using reverse genetics.However,the molecular profiles and complex limitations of human coronaviruses(HCoVs)pose a challenge to ICs development.In this study,we report a novel platform to develop the ICs for HCoV-OC43-VR1558 using a one-step assembly method in yeast by transformation-associated recombination(TAR)technology.Recombinant HCoV-OC43-VR1558,named as rOC43(1558)-WT,was rapidly generated by TAR.In addition,recombinant HCoV-OC43-VR1558-expressing reporter genes,named as rOC43(1558)-ns2FusionRluc,was also generated based on TAR by inserting the ns2 region of the IC with Renilla luciferase(Rluc).We further characterized their replication through virus titration using 50%tissue culture infective dose(TCID50)and indirect immunofluorescence assay(IFA),luciferase reporter assay,and western blotting(WB)assay.The genetic stability of the recombinant HCoV-OC43 was assessed through viral genome sequencing following passaging in BHK-21 cells.These reporter viruses were validated as screening tools for inhibitorsin vitro by evaluating the antiviral activities of remdesivir and chloroquine.The phenotypes of HCoV-OC43-VR1558 and HCoV-OC43-VR759 were comparedin vitro andin vivo.The TAR-based one-step assembly of IC was successfully applied,facilitating the rapid generation of recombinant HCoV-OC43 and providing a useful platform for the investigation of biological mechanisms,development of vaccines and diagnostic tests,and screening inhibitors of HCoVs.
