Prokaryotic Expression And Serological Analysis Of FLAG-Fuseded3A Protein FMDV

Foot-and-mouth disease(FMD) is an acute,feveral and highly contagious viral disease and isaccused by Foot-and-mouth disease virus(FMDV),widely considered as one of the most infectiousanimal disease.FMD has widely spreaded aroud the world.FMDV,the prototype member of the genusAphthovirus of the family Picornaviridae,occurs as seven distinct serotypes(Euroasiatic serotypesA,O,C and Asia1and South African Territories serotypes SAT1,SAT2,and SAT3),there is nocross-protective antibodies among seven serotypes,and multiple subtypes exist in each serotype.3A protein,one of FMDV nonstructural proteins,ranges from143to153aa,almost all mutationslocate at C-terminal,preferentially occurring at positions70to110and130to150.There are two kindsof3A gene in field,one is consisted of153aa,another is composed with143aa,in which has93-102aadeletion or133-143aa deletion.The strain OZK,one of FMDV vaccine strains, has a10amino acidsdeletion corresponding to residues93~102of the other isolates within3A protein, so this strain lost thefirst B cell linear epitope within3A protein,and only infect pigs.Given this,the FLAG tag has beeninserted at92~94amino acid residues within3A protein, and then we have expressed the recombinantFLAG-tagged3A protein, shortly as3AF protein.Meanwhile,the native3A protein of wild type strainhas also exprssed as a control.The results show,both3A and3AF proteins expressed effectively inE.coli, primarily in soluble form.The anti-FLAG monoclonal antibody can specifically recognize theFLAG tag within3AF proten,but it has no reaction with3A protein. Interestingly, both3A and3AFproteins can induce antibodies against3A protein without antibodies against FLAG tag in mice.Thepresent research has laid basis for the rescue and application of FLAG markered FMDV.